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class="vector-toc-numb">2</span> <span>Common applications</span> </div> </a> <ul id="toc-Common_applications-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Psychrometric_properties" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Psychrometric_properties"> <div class="vector-toc-text"> <span class="vector-toc-numb">3</span> <span>Psychrometric properties</span> </div> </a> <button aria-controls="toc-Psychrometric_properties-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Psychrometric properties subsection</span> </button> <ul id="toc-Psychrometric_properties-sublist" class="vector-toc-list"> <li id="toc-Dry-bulb_temperature_(DBT)" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Dry-bulb_temperature_(DBT)"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.1</span> <span>Dry-bulb temperature (DBT)</span> </div> </a> <ul id="toc-Dry-bulb_temperature_(DBT)-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Wet-bulb_temperature_(WBT)" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Wet-bulb_temperature_(WBT)"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.2</span> <span>Wet-bulb temperature (WBT)</span> </div> </a> <ul id="toc-Wet-bulb_temperature_(WBT)-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Dew_point_temperature" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Dew_point_temperature"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.3</span> <span>Dew point temperature</span> </div> </a> <ul id="toc-Dew_point_temperature-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Humidity" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Humidity"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.4</span> <span>Humidity</span> </div> </a> <ul id="toc-Humidity-sublist" class="vector-toc-list"> <li id="toc-Specific_humidity" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#Specific_humidity"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.4.1</span> <span>Specific humidity</span> </div> </a> <ul id="toc-Specific_humidity-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Absolute_humidity" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#Absolute_humidity"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.4.2</span> <span>Absolute humidity</span> </div> </a> <ul id="toc-Absolute_humidity-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Relative_humidity" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#Relative_humidity"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.4.3</span> <span>Relative humidity</span> </div> </a> <ul id="toc-Relative_humidity-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Specific_enthalpy" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Specific_enthalpy"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.5</span> <span>Specific enthalpy</span> </div> </a> <ul id="toc-Specific_enthalpy-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Specific_volume" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Specific_volume"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.6</span> <span>Specific volume</span> </div> </a> <ul id="toc-Specific_volume-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Psychrometric_ratio" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Psychrometric_ratio"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.7</span> <span>Psychrometric ratio</span> </div> </a> <ul id="toc-Psychrometric_ratio-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Humid_heat" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Humid_heat"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.8</span> <span>Humid heat</span> </div> </a> <ul id="toc-Humid_heat-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Pressure" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Pressure"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.9</span> <span>Pressure</span> </div> </a> <ul id="toc-Pressure-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Psychrometric_charts" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Psychrometric_charts"> <div class="vector-toc-text"> <span class="vector-toc-numb">4</span> <span>Psychrometric charts</span> </div> </a> <button aria-controls="toc-Psychrometric_charts-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Psychrometric charts subsection</span> </button> <ul id="toc-Psychrometric_charts-sublist" class="vector-toc-list"> <li id="toc-Terminology" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Terminology"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.1</span> <span>Terminology</span> </div> </a> <ul id="toc-Terminology-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Locating_parameters_on_chart" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Locating_parameters_on_chart"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.2</span> <span>Locating parameters on chart</span> </div> </a> <ul id="toc-Locating_parameters_on_chart-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-How_to_read_the_chart:_fundamental_examples" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#How_to_read_the_chart:_fundamental_examples"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.3</span> <span>How to read the chart: fundamental examples</span> </div> </a> <ul id="toc-How_to_read_the_chart:_fundamental_examples-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Mollier_diagram" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Mollier_diagram"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.4</span> <span>Mollier diagram</span> </div> </a> <ul id="toc-Mollier_diagram-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-See_also" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#See_also"> <div class="vector-toc-text"> <span class="vector-toc-numb">5</span> <span>See also</span> </div> </a> <ul id="toc-See_also-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-References" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#References"> <div class="vector-toc-text"> <span class="vector-toc-numb">6</span> <span>References</span> </div> </a> <ul id="toc-References-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-External_links" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#External_links"> <div class="vector-toc-text"> <span class="vector-toc-numb">7</span> <span>External links</span> </div> </a> <ul id="toc-External_links-sublist" class="vector-toc-list"> </ul> </li> </ul> </div> </div> </nav> </div> </div> <div class="mw-content-container"> <main id="content" class="mw-body"> <header class="mw-body-header vector-page-titlebar"> <nav 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class="firstHeading mw-first-heading"><span class="mw-page-title-main">Psychrometrics</span></h1> <div id="p-lang-btn" class="vector-dropdown mw-portlet mw-portlet-lang" > <input type="checkbox" id="p-lang-btn-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-p-lang-btn" class="vector-dropdown-checkbox mw-interlanguage-selector" aria-label="Go to an article in another language. Available in 18 languages" > <label id="p-lang-btn-label" for="p-lang-btn-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--action-progressive mw-portlet-lang-heading-18" aria-hidden="true" ><span class="vector-icon mw-ui-icon-language-progressive mw-ui-icon-wikimedia-language-progressive"></span> <span class="vector-dropdown-label-text">18 languages</span> </label> <div class="vector-dropdown-content"> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="interlanguage-link interwiki-ar mw-list-item"><a href="https://ar.wikipedia.org/wiki/%D9%82%D9%8A%D8%A7%D8%B3_%D8%A7%D9%84%D8%B1%D8%B7%D9%88%D8%A8%D8%A9" title="قياس الرطوبة – Arabic" lang="ar" hreflang="ar" data-title="قياس الرطوبة" data-language-autonym="العربية" data-language-local-name="Arabic" class="interlanguage-link-target"><span>العربية</span></a></li><li class="interlanguage-link interwiki-ca mw-list-item"><a href="https://ca.wikipedia.org/wiki/Psicrometria" title="Psicrometria – Catalan" lang="ca" hreflang="ca" data-title="Psicrometria" data-language-autonym="Català" data-language-local-name="Catalan" class="interlanguage-link-target"><span>Català</span></a></li><li class="interlanguage-link interwiki-de mw-list-item"><a href="https://de.wikipedia.org/wiki/Psychrometrie" title="Psychrometrie – German" lang="de" hreflang="de" data-title="Psychrometrie" data-language-autonym="Deutsch" data-language-local-name="German" class="interlanguage-link-target"><span>Deutsch</span></a></li><li class="interlanguage-link interwiki-el mw-list-item"><a href="https://el.wikipedia.org/wiki/%CE%A5%CE%B3%CF%81%CE%BF%CE%BC%CE%B5%CF%84%CF%81%CE%AF%CE%B1" title="Υγρομετρία – Greek" lang="el" hreflang="el" data-title="Υγρομετρία" data-language-autonym="Ελληνικά" data-language-local-name="Greek" class="interlanguage-link-target"><span>Ελληνικά</span></a></li><li class="interlanguage-link interwiki-es mw-list-item"><a href="https://es.wikipedia.org/wiki/Psicrometr%C3%ADa" title="Psicrometría – Spanish" lang="es" hreflang="es" data-title="Psicrometría" data-language-autonym="Español" data-language-local-name="Spanish" class="interlanguage-link-target"><span>Español</span></a></li><li class="interlanguage-link interwiki-fa mw-list-item"><a href="https://fa.wikipedia.org/wiki/%D8%B1%D8%B7%D9%88%D8%A8%D8%AA%E2%80%8C%D8%B3%D9%86%D8%AC%DB%8C" title="رطوبت‌سنجی – Persian" lang="fa" hreflang="fa" data-title="رطوبت‌سنجی" data-language-autonym="فارسی" data-language-local-name="Persian" class="interlanguage-link-target"><span>فارسی</span></a></li><li class="interlanguage-link interwiki-fr mw-list-item"><a href="https://fr.wikipedia.org/wiki/Psychrom%C3%A9trie" title="Psychrométrie – French" lang="fr" hreflang="fr" data-title="Psychrométrie" data-language-autonym="Français" data-language-local-name="French" class="interlanguage-link-target"><span>Français</span></a></li><li class="interlanguage-link interwiki-gl mw-list-item"><a href="https://gl.wikipedia.org/wiki/Psicrometr%C3%ADa" title="Psicrometría – Galician" lang="gl" hreflang="gl" data-title="Psicrometría" data-language-autonym="Galego" data-language-local-name="Galician" class="interlanguage-link-target"><span>Galego</span></a></li><li class="interlanguage-link interwiki-ko mw-list-item"><a href="https://ko.wikipedia.org/wiki/%EC%8A%B5%EA%B3%B5%EA%B8%B0%EC%84%A0%EB%8F%84" title="습공기선도 – Korean" lang="ko" hreflang="ko" data-title="습공기선도" data-language-autonym="한국어" data-language-local-name="Korean" class="interlanguage-link-target"><span>한국어</span></a></li><li class="interlanguage-link interwiki-hr mw-list-item"><a href="https://hr.wikipedia.org/wiki/Psihrometrija" title="Psihrometrija – Croatian" lang="hr" hreflang="hr" data-title="Psihrometrija" data-language-autonym="Hrvatski" data-language-local-name="Croatian" class="interlanguage-link-target"><span>Hrvatski</span></a></li><li class="interlanguage-link interwiki-it mw-list-item"><a href="https://it.wikipedia.org/wiki/Psicrometria" title="Psicrometria – Italian" lang="it" hreflang="it" data-title="Psicrometria" data-language-autonym="Italiano" data-language-local-name="Italian" class="interlanguage-link-target"><span>Italiano</span></a></li><li class="interlanguage-link interwiki-hu mw-list-item"><a href="https://hu.wikipedia.org/wiki/Pszichrometria" title="Pszichrometria – Hungarian" lang="hu" hreflang="hu" data-title="Pszichrometria" data-language-autonym="Magyar" data-language-local-name="Hungarian" class="interlanguage-link-target"><span>Magyar</span></a></li><li class="interlanguage-link interwiki-ja mw-list-item"><a href="https://ja.wikipedia.org/wiki/%E6%B9%BF%E3%82%8A%E7%A9%BA%E6%B0%97%E7%B7%9A%E5%9B%B3" title="湿り空気線図 – Japanese" lang="ja" hreflang="ja" data-title="湿り空気線図" data-language-autonym="日本語" data-language-local-name="Japanese" class="interlanguage-link-target"><span>日本語</span></a></li><li class="interlanguage-link interwiki-sc mw-list-item"><a href="https://sc.wikipedia.org/wiki/Psicrometria" title="Psicrometria – Sardinian" lang="sc" hreflang="sc" data-title="Psicrometria" data-language-autonym="Sardu" data-language-local-name="Sardinian" class="interlanguage-link-target"><span>Sardu</span></a></li><li class="interlanguage-link interwiki-sh mw-list-item"><a href="https://sh.wikipedia.org/wiki/Psihrometrija" title="Psihrometrija – Serbo-Croatian" lang="sh" hreflang="sh" data-title="Psihrometrija" data-language-autonym="Srpskohrvatski / српскохрватски" data-language-local-name="Serbo-Croatian" class="interlanguage-link-target"><span>Srpskohrvatski / српскохрватски</span></a></li><li class="interlanguage-link interwiki-th mw-list-item"><a href="https://th.wikipedia.org/wiki/%E0%B9%84%E0%B8%8B%E0%B9%82%E0%B8%84%E0%B8%A3%E0%B9%80%E0%B8%A1%E0%B8%97%E0%B8%A3%E0%B8%B5" title="ไซโครเมทรี – Thai" lang="th" hreflang="th" data-title="ไซโครเมทรี" data-language-autonym="ไทย" data-language-local-name="Thai" class="interlanguage-link-target"><span>ไทย</span></a></li><li class="interlanguage-link interwiki-tr mw-list-item"><a href="https://tr.wikipedia.org/wiki/Psikrometri" title="Psikrometri – Turkish" lang="tr" hreflang="tr" data-title="Psikrometri" data-language-autonym="Türkçe" data-language-local-name="Turkish" class="interlanguage-link-target"><span>Türkçe</span></a></li><li class="interlanguage-link interwiki-zh mw-list-item"><a href="https://zh.wikipedia.org/wiki/%E6%B8%AC%E6%BF%95%E5%AD%B8" title="測濕學 – Chinese" lang="zh" hreflang="zh" data-title="測濕學" data-language-autonym="中文" data-language-local-name="Chinese" class="interlanguage-link-target"><span>中文</span></a></li> </ul> <div class="after-portlet after-portlet-lang"><span class="wb-langlinks-edit wb-langlinks-link"><a href="https://www.wikidata.org/wiki/Special:EntityPage/Q899784#sitelinks-wikipedia" title="Edit interlanguage links" class="wbc-editpage">Edit links</a></span></div> </div> </div> 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href="/wiki/File:Cloud_forest_mount_kinabalu-withHygrom.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/8/8f/Cloud_forest_mount_kinabalu-withHygrom.jpg/220px-Cloud_forest_mount_kinabalu-withHygrom.jpg" decoding="async" width="220" height="210" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/8/8f/Cloud_forest_mount_kinabalu-withHygrom.jpg/330px-Cloud_forest_mount_kinabalu-withHygrom.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/8/8f/Cloud_forest_mount_kinabalu-withHygrom.jpg/440px-Cloud_forest_mount_kinabalu-withHygrom.jpg 2x" data-file-width="781" data-file-height="744" /></a></span></td></tr><tr><th class="sidebar-heading" style="background:#C7E6A5;"> Specific concepts</th></tr><tr><td class="sidebar-content"> <div class="plainlist"> <ul><li><a href="/wiki/Dew_point" title="Dew point">Dew point</a></li> <li><a href="/wiki/Dew_point_depression" title="Dew point depression">Dew point depression</a></li> <li><a class="mw-selflink selflink">Psychrometrics</a></li></ul> </div></td> </tr><tr><th class="sidebar-heading" style="background:#C7E6A5;"> General concepts</th></tr><tr><td class="sidebar-content"> <div class="hlist"> <ul><li><a href="/wiki/Atmosphere_of_Earth" title="Atmosphere of Earth">Air</a></li> <li><a href="/wiki/Concentration" title="Concentration">Concentration</a></li> <li><a href="/wiki/Density" title="Density">Density</a></li> <li><a href="/wiki/Dew" title="Dew">Dew</a></li> <li><a href="/wiki/Evaporation" title="Evaporation">Evaporation</a></li> <li><a href="/wiki/Humidity_buffering" title="Humidity buffering">Humidity buffering</a></li> <li>(<a href="/wiki/Atmospheric_pressure" title="Atmospheric pressure">Atm.</a>) <a class="mw-selflink-fragment" href="#Pressure">Pressure</a></li> <li><a href="/wiki/Water#Liquid_water" title="Water">Liquid water</a></li> <li><a href="/wiki/Avogadro%27s_law" title="Avogadro's law">Avogadro's law</a></li> <li><a href="/wiki/Nucleation" title="Nucleation">Nucleation</a></li> <li><a href="/wiki/Thermodynamic_equilibrium" title="Thermodynamic equilibrium">Thermodynamic equilibrium</a></li></ul> </div></td> </tr><tr><th class="sidebar-heading" style="background:#C7E6A5;"> Measures and instruments</th></tr><tr><td class="sidebar-content"> <div class="hlist"> <ul><li><a href="/wiki/Heat_index" title="Heat index">Heat index</a></li> <li><a href="/wiki/Saturation_vapor_density" title="Saturation vapor density">Sat. vap. density</a></li> <li><a href="/wiki/Mixing_ratio" title="Mixing ratio">Mixing ratio</a></li> <li><a href="/wiki/Water_activity" title="Water activity">Water activity</a></li> <li><a href="/wiki/Humidity_indicator" class="mw-redirect" title="Humidity indicator">H. indicator</a> <ul><li><a href="/wiki/Humidity_indicator_card" title="Humidity indicator card">card</a></li></ul></li> <li><a href="/wiki/Hygrometer" title="Hygrometer">Hygrometer</a></li> <li><a href="/wiki/Dry-bulb_temperature" title="Dry-bulb temperature">Dry</a>/<a href="/wiki/Wet-bulb_temperature" title="Wet-bulb temperature">Wet-bulb temperature</a></li></ul> </div></td> </tr><tr><td class="sidebar-navbar"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><style data-mw-deduplicate="TemplateStyles:r1239400231">.mw-parser-output .navbar{display:inline;font-size:88%;font-weight:normal}.mw-parser-output .navbar-collapse{float:left;text-align:left}.mw-parser-output .navbar-boxtext{word-spacing:0}.mw-parser-output .navbar ul{display:inline-block;white-space:nowrap;line-height:inherit}.mw-parser-output .navbar-brackets::before{margin-right:-0.125em;content:"[ "}.mw-parser-output .navbar-brackets::after{margin-left:-0.125em;content:" ]"}.mw-parser-output .navbar li{word-spacing:-0.125em}.mw-parser-output .navbar a>span,.mw-parser-output .navbar a>abbr{text-decoration:inherit}.mw-parser-output .navbar-mini abbr{font-variant:small-caps;border-bottom:none;text-decoration:none;cursor:inherit}.mw-parser-output .navbar-ct-full{font-size:114%;margin:0 7em}.mw-parser-output .navbar-ct-mini{font-size:114%;margin:0 4em}html.skin-theme-clientpref-night .mw-parser-output .navbar li a abbr{color:var(--color-base)!important}@media(prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .navbar li a abbr{color:var(--color-base)!important}}@media print{.mw-parser-output .navbar{display:none!important}}</style><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Humidity" title="Template:Humidity"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Humidity" title="Template talk:Humidity"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Humidity" title="Special:EditPage/Template:Humidity"><abbr title="Edit this template">e</abbr></a></li></ul></div></td></tr></tbody></table> <p><b>Psychrometrics</b> (or <b>psychrometry</b>, from <a href="/wiki/Greek_language" title="Greek language">Greek</a> <i> </i>ψυχρόν<i> (psuchron)</i> 'cold' and <i> </i>μέτρον<i> (metron)</i> 'means of measurement';<sup id="cite_ref-1" class="reference"><a href="#cite_note-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-2" class="reference"><a href="#cite_note-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> also called <b>hygrometry</b>) is the field of engineering concerned with the physical and <a href="/wiki/Thermodynamic" class="mw-redirect" title="Thermodynamic">thermodynamic</a> properties of <a href="/wiki/Gas" title="Gas">gas</a>-<a href="/wiki/Vapor" title="Vapor">vapor</a> <a href="/wiki/Mixture" title="Mixture">mixtures</a>. </p> <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="History">History</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Psychrometrics&action=edit&section=1" title="Edit section: History"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>With the inventions of the hygrometer and thermometer, the theories of combining the two began to emerge during the sixteenth and seventeenth centuries. In 1818, a German inventor, <a href="/wiki/Ernst_Ferdinand_August" title="Ernst Ferdinand August">Ernst Ferdinand August</a> (1795-1870), patented the term “psychrometer”, from the Greek language meaning “cold measure”. The psychrometer is a <a href="/wiki/Hygrometer" title="Hygrometer">hygrometric</a> instrument based on the principle that dry air enhances evaporation, unlike wet air, which slows it. <sup id="cite_ref-3" class="reference"><a href="#cite_note-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="Common_applications">Common applications</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Psychrometrics&action=edit&section=2" title="Edit section: Common applications"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1251242444">.mw-parser-output .ambox{border:1px solid #a2a9b1;border-left:10px solid #36c;background-color:#fbfbfb;box-sizing:border-box}.mw-parser-output .ambox+link+.ambox,.mw-parser-output .ambox+link+style+.ambox,.mw-parser-output .ambox+link+link+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+style+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+link+.ambox{margin-top:-1px}html body.mediawiki .mw-parser-output .ambox.mbox-small-left{margin:4px 1em 4px 0;overflow:hidden;width:238px;border-collapse:collapse;font-size:88%;line-height:1.25em}.mw-parser-output .ambox-speedy{border-left:10px solid #b32424;background-color:#fee7e6}.mw-parser-output .ambox-delete{border-left:10px solid #b32424}.mw-parser-output .ambox-content{border-left:10px solid #f28500}.mw-parser-output .ambox-style{border-left:10px solid #fc3}.mw-parser-output .ambox-move{border-left:10px solid #9932cc}.mw-parser-output .ambox-protection{border-left:10px solid #a2a9b1}.mw-parser-output .ambox .mbox-text{border:none;padding:0.25em 0.5em;width:100%}.mw-parser-output .ambox .mbox-image{border:none;padding:2px 0 2px 0.5em;text-align:center}.mw-parser-output .ambox .mbox-imageright{border:none;padding:2px 0.5em 2px 0;text-align:center}.mw-parser-output .ambox .mbox-empty-cell{border:none;padding:0;width:1px}.mw-parser-output .ambox .mbox-image-div{width:52px}@media(min-width:720px){.mw-parser-output .ambox{margin:0 10%}}@media print{body.ns-0 .mw-parser-output .ambox{display:none!important}}</style><table class="box-Unreferenced_section plainlinks metadata ambox ambox-content ambox-Unreferenced" role="presentation"><tbody><tr><td class="mbox-image"><div class="mbox-image-div"><span typeof="mw:File"><a href="/wiki/File:Question_book-new.svg" class="mw-file-description"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/9/99/Question_book-new.svg/50px-Question_book-new.svg.png" decoding="async" width="50" height="39" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/9/99/Question_book-new.svg/75px-Question_book-new.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/9/99/Question_book-new.svg/100px-Question_book-new.svg.png 2x" data-file-width="512" data-file-height="399" /></a></span></div></td><td class="mbox-text"><div class="mbox-text-span">This section <b>does not <a href="/wiki/Wikipedia:Citing_sources" title="Wikipedia:Citing sources">cite</a> any <a href="/wiki/Wikipedia:Verifiability" title="Wikipedia:Verifiability">sources</a></b>.<span class="hide-when-compact"> Please help <a href="/wiki/Special:EditPage/Psychrometrics" title="Special:EditPage/Psychrometrics">improve this section</a> by <a href="/wiki/Help:Referencing_for_beginners" title="Help:Referencing for beginners">adding citations to reliable sources</a>. Unsourced material may be challenged and <a href="/wiki/Wikipedia:Verifiability#Burden_of_evidence" title="Wikipedia:Verifiability">removed</a>.</span> <span class="date-container"><i>(<span class="date">March 2021</span>)</i></span><span class="hide-when-compact"><i> (<small><a href="/wiki/Help:Maintenance_template_removal" title="Help:Maintenance template removal">Learn how and when to remove this message</a></small>)</i></span></div></td></tr></tbody></table> <p>Although the principles of psychrometry apply to any physical system consisting of gas-vapor mixtures, the most common system of interest is the mixture of water vapor and air, because of its application in <a href="/wiki/HVAC" class="mw-redirect" title="HVAC">heating, ventilation, and air-conditioning</a> and <a href="/wiki/Meteorology" title="Meteorology">meteorology</a>. In human terms, our <a href="/wiki/Thermal_comfort" title="Thermal comfort">thermal comfort</a> is in large part a consequence of not just the temperature of the surrounding air, but (because we cool ourselves via perspiration) the extent to which that air is saturated with water vapor. </p><p>Many substances are <a href="/wiki/Hygroscopy" title="Hygroscopy">hygroscopic</a>, meaning they attract water, usually in proportion to the relative humidity or above a <a href="/wiki/Critical_relative_humidity" title="Critical relative humidity">critical relative humidity</a>. Such substances include cotton, paper, cellulose, other wood products, sugar, <a href="/wiki/Calcium_oxide" title="Calcium oxide">calcium oxide</a> (burned lime) and many chemicals and fertilizers. Industries that use these materials are concerned with relative humidity control in production and storage of such materials. Relative humidity is often controlled in manufacturing areas where flammable materials are handled, to avoid fires caused by the static electricity discharges that can occur in very dry air. </p><p>In industrial drying applications, such as drying paper, manufacturers usually try to achieve an optimum between low relative humidity, which increases the drying rate, and energy usage, which decreases as exhaust relative humidity increases. In many industrial applications it is important to avoid <a href="/wiki/Condensation" title="Condensation">condensation</a> that would ruin product or cause corrosion. </p><p>Molds and fungi can be controlled by keeping relative humidity low. Wood destroying fungi generally do not grow at relative humidities below 75%. </p> <div class="mw-heading mw-heading2"><h2 id="Psychrometric_properties">Psychrometric properties</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Psychrometrics&action=edit&section=3" title="Edit section: Psychrometric properties"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="mw-heading mw-heading3"><h3 id="Dry-bulb_temperature_(DBT)"><span id="Dry-bulb_temperature_.28DBT.29"></span>Dry-bulb temperature (DBT)</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Psychrometrics&action=edit&section=4" title="Edit section: Dry-bulb temperature (DBT)"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Dry-bulb_temperature" title="Dry-bulb temperature">Dry-bulb temperature</a></div> <p>The dry-bulb temperature is the temperature indicated by a thermometer exposed to the air in a place sheltered from direct solar radiation. The term dry-bulb is customarily added to temperature to distinguish it from wet-bulb and dew point temperature. In meteorology and psychrometrics the word temperature by itself without a prefix usually means dry-bulb temperature. Technically, the temperature registered by the dry-bulb thermometer of a psychrometer. The name implies that the sensing bulb or element is in fact dry. <a href="/wiki/World_Meteorological_Organization" title="World Meteorological Organization">WMO</a> provides a 23-page chapter on the measurement of temperature.<sup id="cite_ref-4" class="reference"><a href="#cite_note-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="Wet-bulb_temperature_(WBT)"><span id="Wet-bulb_temperature_.28WBT.29"></span>Wet-bulb temperature (WBT)</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Psychrometrics&action=edit&section=5" title="Edit section: Wet-bulb temperature (WBT)"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Wet-bulb_temperature" title="Wet-bulb temperature">Wet-bulb temperature</a></div> <p>The thermodynamic wet-bulb temperature is a <a href="/wiki/Thermodynamic_properties" class="mw-redirect" title="Thermodynamic properties">thermodynamic property</a> of a mixture of air and water vapor. The value indicated by a wet-bulb thermometer often provides an adequate approximation of the thermodynamic wet-bulb temperature. </p><p>The accuracy of a simple wet-bulb thermometer depends on how fast air passes over the bulb and how well the thermometer is shielded from the radiant temperature of its surroundings. Speeds up to 5,000 ft/min (~60 mph, 25.4 m/s) are best but it may be dangerous to move a thermometer at that speed. Errors up to 15% can occur if the air movement is too slow or if there is too much radiant heat present (from sunlight, for example). </p><p>A wet bulb temperature taken with air moving at about 1–2 m/s is referred to as a <b>screen temperature</b>, whereas a temperature taken with air moving about 3.5 m/s or more is referred to as <b>sling temperature</b>. </p><p>A <a href="/wiki/Psychrometer" class="mw-redirect" title="Psychrometer">psychrometer</a> is a device that includes both a dry-bulb and a wet-bulb thermometer. A <b>sling psychrometer</b> requires manual operation to create the airflow over the bulbs, but a <b>powered psychrometer</b> includes a fan for this function. Knowing both the dry-bulb temperature (DBT) and wet-bulb temperature (WBT), one can determine the relative humidity (RH) from the psychrometric chart appropriate to the air pressure. </p> <div class="mw-heading mw-heading3"><h3 id="Dew_point_temperature">Dew point temperature</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Psychrometrics&action=edit&section=6" title="Edit section: Dew point temperature"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Dew_point_temperature" class="mw-redirect" title="Dew point temperature">Dew point temperature</a></div> <p>The saturation temperature of the moisture present in the sample of air, it can also be defined as the temperature at which the vapour changes into liquid (condensation). Usually the level at which water vapor changes into liquid marks the base of the cloud in the atmosphere hence called condensation level. So the temperature value that allows this process (condensation) to take place is called the 'dew point temperature'. A simplified definition is the temperature at which the water vapour turns into "dew" (Chamunoda Zambuko 2012). </p> <div class="mw-heading mw-heading3"><h3 id="Humidity">Humidity</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Psychrometrics&action=edit&section=7" title="Edit section: Humidity"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Humidity" title="Humidity">Humidity</a></div> <div class="mw-heading mw-heading4"><h4 id="Specific_humidity">Specific humidity</h4><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Psychrometrics&action=edit&section=8" title="Edit section: Specific humidity"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Specific humidity is defined as the mass of water vapor as a proportion of the mass of the moist air sample (including both dry air and the water vapor); it is closely related to humidity ratio and always lower in value. </p> <div class="mw-heading mw-heading4"><h4 id="Absolute_humidity">Absolute humidity</h4><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Psychrometrics&action=edit&section=9" title="Edit section: Absolute humidity"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The mass of water vapor per unit mass of dry air containing the water vapor. This quantity is also known as the water vapor density.<sup id="cite_ref-5" class="reference"><a href="#cite_note-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading4"><h4 id="Relative_humidity">Relative humidity</h4><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Psychrometrics&action=edit&section=10" title="Edit section: Relative humidity"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Is a ratio, expressed in percent, of the amount of atmospheric moisture present relative to the amount that would be present if the air was saturated. </p> <div class="mw-heading mw-heading3"><h3 id="Specific_enthalpy">Specific enthalpy</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Psychrometrics&action=edit&section=11" title="Edit section: Specific enthalpy"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Analogous to the specific enthalpy of a pure substance. In psychrometrics, the term quantifies the total energy of both the dry air and water vapour per kilogram of dry air. </p> <div class="mw-heading mw-heading3"><h3 id="Specific_volume">Specific volume</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Psychrometrics&action=edit&section=12" title="Edit section: Specific volume"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Analogous to the specific volume of a pure substance. However, in psychrometrics, the term quantifies the total volume of both the dry air and water vapour per unit mass of dry air. </p> <div class="mw-heading mw-heading3"><h3 id="Psychrometric_ratio">Psychrometric ratio</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Psychrometrics&action=edit&section=13" title="Edit section: Psychrometric ratio"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The <b>psychrometric ratio</b> is the ratio of the <a href="/wiki/Heat_transfer_coefficient" title="Heat transfer coefficient">heat transfer coefficient</a> to the product of <a href="/wiki/Mass_transfer_coefficient" title="Mass transfer coefficient">mass transfer coefficient</a> and humid heat at a wetted surface. It may be evaluated with the following equation:<sup id="cite_ref-6" class="reference"><a href="#cite_note-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-7" class="reference"><a href="#cite_note-7"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup> </p> <dl><dd><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle r={\frac {h_{c}}{k_{y}c_{s}}}\,}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>r</mi> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <msub> <mi>h</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>c</mi> </mrow> </msub> <mrow> <msub> <mi>k</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>y</mi> </mrow> </msub> <msub> <mi>c</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>s</mi> </mrow> </msub> </mrow> </mfrac> </mrow> <mspace width="thinmathspace" /> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle r={\frac {h_{c}}{k_{y}c_{s}}}\,}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/7fdd70ea511b29964158ec73dee9a2fdc38b04ab" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -2.671ex; width:9.641ex; height:6.176ex;" alt="{\displaystyle r={\frac {h_{c}}{k_{y}c_{s}}}\,}"></span></dd></dl> <dl><dd>where: <dl><dd><b><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle r}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>r</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle r}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/0d1ecb613aa2984f0576f70f86650b7c2a132538" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.049ex; height:1.676ex;" alt="{\displaystyle r}"></span></b> <span class="nowrap"> </span> = psychrometric ratio, dimensionless</dd> <dd><b><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle h_{c}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <msub> <mi>h</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>c</mi> </mrow> </msub> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle h_{c}}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/d06972075e10d9390c826454530d3e2a6351dc45" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:2.283ex; height:2.509ex;" alt="{\displaystyle h_{c}}"></span></b> <span class="nowrap"></span> = convective heat transfer coefficient, W m<sup>−2</sup> K<sup>−1</sup></dd> <dd><b><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle k_{y}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <msub> <mi>k</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>y</mi> </mrow> </msub> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle k_{y}}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/c03d994b4735244db4b14200c7500bc3fb98f5f2" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.005ex; width:2.261ex; height:2.843ex;" alt="{\displaystyle k_{y}}"></span></b> <span class="nowrap"></span> = convective mass transfer coefficient, kg m<sup>−2</sup> s<sup>−1</sup></dd> <dd><b><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle c_{s}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <msub> <mi>c</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>s</mi> </mrow> </msub> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle c_{s}}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/75b83e050da28fa0d83e2aa786963805742ab756" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:2.01ex; height:2.009ex;" alt="{\displaystyle c_{s}}"></span></b> <span class="nowrap"></span> = humid heat, J kg<sup>−1</sup> K<sup>−1</sup></dd></dl></dd></dl> <p>The psychrometric ratio is an important property in the area of psychrometry, as it relates the absolute humidity and saturation humidity to the difference between the dry bulb temperature and the <a href="/wiki/Adiabatic_saturation_temperature" class="mw-redirect" title="Adiabatic saturation temperature">adiabatic saturation temperature</a>. </p><p>Mixtures of air and water vapor are the most common systems encountered in psychrometry. The psychrometric ratio of air-water vapor mixtures is approximately unity, which implies that the difference between the adiabatic saturation temperature and wet bulb temperature of air-water vapor mixtures is small. This property of air-water vapor systems simplifies drying and cooling calculations often performed using psychrometric relationships. </p> <div class="mw-heading mw-heading3"><h3 id="Humid_heat">Humid heat</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Psychrometrics&action=edit&section=14" title="Edit section: Humid heat"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p><b>Humid heat</b> is the constant-pressure <a href="/wiki/Specific_heat" class="mw-redirect" title="Specific heat">specific heat</a> of moist air, per unit mass of the dry air.<sup id="cite_ref-8" class="reference"><a href="#cite_note-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup> The humid heat is the amount of heat required to change the temperature of unit mass of a water vapor - air mixture by 1 °C. </p> <div class="mw-heading mw-heading3"><h3 id="Pressure">Pressure</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Psychrometrics&action=edit&section=15" title="Edit section: Pressure"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Many psychrometric properties are dependent on <a href="/wiki/Pressure" title="Pressure">pressure</a> concept: </p> <ul><li><a href="/wiki/Vapor_pressure" title="Vapor pressure">vapor pressure</a> of water;</li> <li><a href="/wiki/Atmospheric_pressure" title="Atmospheric pressure">atmospheric pressure</a> at the location of the sample.</li></ul> <div class="mw-heading mw-heading2"><h2 id="Psychrometric_charts">Psychrometric charts</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Psychrometrics&action=edit&section=16" title="Edit section: Psychrometric charts"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p><sup id="cite_ref-9" class="reference"><a href="#cite_note-9"><span class="cite-bracket">[</span>9<span class="cite-bracket">]</span></a></sup> </p> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:PsychrometricChart.SeaLevel.SI.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/9/9d/PsychrometricChart.SeaLevel.SI.svg/350px-PsychrometricChart.SeaLevel.SI.svg.png" decoding="async" width="350" height="256" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/9/9d/PsychrometricChart.SeaLevel.SI.svg/525px-PsychrometricChart.SeaLevel.SI.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/9/9d/PsychrometricChart.SeaLevel.SI.svg/700px-PsychrometricChart.SeaLevel.SI.svg.png 2x" data-file-width="1409" data-file-height="1031" /></a><figcaption>A psychrometric chart for sea-level elevation</figcaption></figure> <div class="mw-heading mw-heading3"><h3 id="Terminology">Terminology</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Psychrometrics&action=edit&section=17" title="Edit section: Terminology"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>A psychrometric chart is a graph of the thermodynamic parameters of moist air at a constant pressure, often equated to an elevation relative to sea level. The <a href="/wiki/ASHRAE" title="ASHRAE">ASHRAE</a>-style psychrometric chart, shown here, was pioneered by <a href="/wiki/Willis_Carrier" title="Willis Carrier">Willis Carrier</a> in 1904.<sup id="cite_ref-10" class="reference"><a href="#cite_note-10"><span class="cite-bracket">[</span>10<span class="cite-bracket">]</span></a></sup> It depicts these parameters and is thus a graphical <a href="/wiki/Equation_of_state" title="Equation of state">equation of state</a>. The parameters are: </p> <ul><li><a href="/wiki/Dry-bulb_temperature" title="Dry-bulb temperature">Dry-bulb temperature</a> (<i>DBT</i>) is that of an air sample, as determined by an ordinary thermometer. It is typically plotted as the <a href="/wiki/X-axis" class="mw-redirect" title="X-axis">abscissa (horizontal axis)</a> of the graph. The SI units for temperature are <a href="/wiki/Kelvin" title="Kelvin">kelvins</a> or <a href="/wiki/Degrees_Celsius" class="mw-redirect" title="Degrees Celsius">degrees Celsius</a>; other units are <a href="/wiki/Degrees_Fahrenheit" class="mw-redirect" title="Degrees Fahrenheit">degrees Fahrenheit</a> and <a href="/wiki/Degrees_Rankine" class="mw-redirect" title="Degrees Rankine">degrees Rankine</a>.</li> <li><a href="/wiki/Wet-bulb_temperature" title="Wet-bulb temperature">Wet-bulb temperature</a> (<i>WBT</i>) is that of an air sample after it has passed through a constant-pressure, ideal, adiabatic saturation process, that is, after the air has passed over a large surface of liquid water in an insulated channel. In practice this is the reading of a thermometer whose sensing bulb is covered with a wet sock evaporating into a rapid stream of the sample air (see <a href="/wiki/Hygrometer" title="Hygrometer">Hygrometer</a>). When the air sample is pre-saturated with water, the WBT will read the same as the DBT. The slope of lines of constant WBT is the ratio between the heat of vaporization of water and the specific heat of dry air, roughly 0.4.</li> <li><a href="/wiki/Dew_point" title="Dew point">Dew point</a> temperature (<i>DPT</i>) is the temperature at which a moist air sample at the same pressure would reach water vapor "saturation." At this point further removal of heat would result in water vapor condensing into liquid water fog or, if below <a href="/wiki/Freezing_point" class="mw-redirect" title="Freezing point">freezing point</a>, solid <a href="/wiki/Hoarfrost" class="mw-redirect" title="Hoarfrost">hoarfrost</a>. The dew point temperature is measured easily and provides useful information, but is normally not considered an independent property of the air sample as it duplicates information available via other humidity properties and the saturation curve.</li> <li><a href="/wiki/Relative_humidity" class="mw-redirect" title="Relative humidity">Relative humidity</a> (<i>RH</i>) is the ratio of the mole fraction of water vapor to the mole fraction of saturated moist air at the same temperature and pressure. RH is dimensionless, and is usually expressed as a percentage. Lines of constant RH reflect the physics of air and water: they are determined via experimental measurement. The concept that air "holds" moisture, or that moisture "dissolves" in dry air and saturates the solution at some proportion, is erroneous (albeit widespread); see <a href="/wiki/Relative_humidity" class="mw-redirect" title="Relative humidity">relative humidity</a> for further details.</li> <li><a href="/wiki/Mixing_ratio" title="Mixing ratio">Humidity ratio</a> is the proportion of mass of water vapor per unit mass of dry air at the given conditions (DBT, WBT, DPT, RH, etc.). It is also known as the moisture content or mixing ratio. It is typically plotted as the <a href="/wiki/Y-axis" class="mw-redirect" title="Y-axis">ordinate (vertical axis)</a> of the graph. For a given DBT there will be a particular humidity ratio for which the air sample is at 100% relative humidity: the relationship reflects the physics of water and air and must be determined by measurement. The dimensionless humidity ratio is typically expressed as grams of water per kilogram of dry air, or <a href="/wiki/Grain_(unit)" title="Grain (unit)">grains</a> of water per pound of air (7000 grains equal 1 pound).</li> <li><a href="/wiki/Specific_enthalpy" class="mw-redirect" title="Specific enthalpy">Specific enthalpy</a>, symbolized by <i>h</i>, is the sum of the internal (heat) energy of the moist air in question, including the heat of the air and water vapor within. Also called heat content per unit mass. In the approximation of ideal gases, lines of constant enthalpy are parallel to lines of constant WBT. Enthalpy is given in (SI) joules per kilogram of air, or BTU per pound of dry air.</li> <li>Specific volume is the volume of the mixture (dry air plus the water vapor) containing one unit of mass of "dry air". The SI units are cubic meters per kilogram of dry air; other units are cubic feet per pound of dry air. The inverse of specific volume is usually confused as the density of the mixture.<sup id="cite_ref-11" class="reference"><a href="#cite_note-11"><span class="cite-bracket">[</span>11<span class="cite-bracket">]</span></a></sup> However, to obtain the actual mixture density (<span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \rho }"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>ρ</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \rho }</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/1f7d439671d1289b6a816e6af7a304be40608d64" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:1.202ex; height:2.176ex;" alt="{\displaystyle \rho }"></span>) one must multiply the inverse of the specific volume by unity plus the humidity ratio value at the point of interest:<sup id="cite_ref-12" class="reference"><a href="#cite_note-12"><span class="cite-bracket">[</span>12<span class="cite-bracket">]</span></a></sup></li></ul> <dl><dd><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \rho ={\frac {M_{da}+M_{w}}{V}}\,=\left({\frac {1}{v}}\right)(1+W)}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>ρ</mi> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mrow> <msub> <mi>M</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>d</mi> <mi>a</mi> </mrow> </msub> <mo>+</mo> <msub> <mi>M</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>w</mi> </mrow> </msub> </mrow> <mi>V</mi> </mfrac> </mrow> <mspace width="thinmathspace" /> <mo>=</mo> <mrow> <mo>(</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mn>1</mn> <mi>v</mi> </mfrac> </mrow> <mo>)</mo> </mrow> <mo stretchy="false">(</mo> <mn>1</mn> <mo>+</mo> <mi>W</mi> <mo stretchy="false">)</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \rho ={\frac {M_{da}+M_{w}}{V}}\,=\left({\frac {1}{v}}\right)(1+W)}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/057062801b8ce793b76a9f89d22848b36ca9c404" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -2.505ex; width:33.395ex; height:6.176ex;" alt="{\displaystyle \rho ={\frac {M_{da}+M_{w}}{V}}\,=\left({\frac {1}{v}}\right)(1+W)}"></span></dd></dl> <dl><dd>where: <dl><dd><b><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle M_{da}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <msub> <mi>M</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>d</mi> <mi>a</mi> </mrow> </msub> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle M_{da}}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/13a3b592d4b4b5b9886c53d2ab77c94e1a42c04e" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:4.216ex; height:2.509ex;" alt="{\displaystyle M_{da}}"></span></b> <span class="nowrap"> </span> = mass of dry air</dd> <dd><b><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle M_{w}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <msub> <mi>M</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>w</mi> </mrow> </msub> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle M_{w}}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/bd43aab3f1711f5a0c782b39560e44d029e81b83" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:3.663ex; height:2.509ex;" alt="{\displaystyle M_{w}}"></span></b> <span class="nowrap">  </span> = mass of water vapor</dd> <dd><b><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle V}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>V</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle V}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/af0f6064540e84211d0ffe4dac72098adfa52845" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.787ex; height:2.176ex;" alt="{\displaystyle V}"></span></b> <span class="nowrap">      </span> = total volume</dd> <dd><b><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle v}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>v</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle v}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/e07b00e7fc0847fbd16391c778d65bc25c452597" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.128ex; height:1.676ex;" alt="{\displaystyle v}"></span></b> <span class="nowrap">       </span> = moist air specific volume, m<sup>3</sup> kg<sup>−1</sup></dd> <dd><b><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle W={\frac {M_{w}}{M_{da}}}\,}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>W</mi> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <msub> <mi>M</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>w</mi> </mrow> </msub> <msub> <mi>M</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>d</mi> <mi>a</mi> </mrow> </msub> </mfrac> </mrow> <mspace width="thinmathspace" /> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle W={\frac {M_{w}}{M_{da}}}\,}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/6fbaefb8541ededcbf72bbdb35f0b65d0c4e4661" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -2.338ex; width:10.973ex; height:5.676ex;" alt="{\displaystyle W={\frac {M_{w}}{M_{da}}}\,}"></span></b> = humidity ratio</dd></dl></dd></dl> <p>The psychrometric chart allows all the parameters of some moist air to be determined from any three independent parameters, one of which must be the pressure. Changes in <i>state</i>, such as when two air streams mix, can be modeled easily and somewhat graphically using the correct psychrometric chart for the location's air pressure or elevation relative to sea level. For locations at not more than 2000 ft (600 m) of altitude it is common practice to use the sea-level psychrometric chart. </p><p>In the <i>ω</i>-<i>t</i> chart, the dry bulb temperature (<i>t</i>) appears as the abscissa (horizontal axis) and the humidity ratio (<i>ω</i>) appear as the ordinate (vertical axis). A chart is valid for a given air pressure (or elevation above sea level). From any two independent ones of the six parameters dry bulb temperature, wet bulb temperature, relative humidity, humidity ratio, specific enthalpy, and specific volume, all the others can be determined. There are <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \left({6 \atop 2}\right)=15}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mrow> <mo>(</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac linethickness="0"> <mn>6</mn> <mn>2</mn> </mfrac> </mrow> <mo>)</mo> </mrow> <mo>=</mo> <mn>15</mn> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \left({6 \atop 2}\right)=15}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/043b517c74cbb876fd605fb7fd894b1df7f00083" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -2.505ex; width:10.564ex; height:6.176ex;" alt="{\displaystyle \left({6 \atop 2}\right)=15}"></span> possible <a href="/wiki/Combination" title="Combination">combinations</a> of independent and derived parameters. </p> <div class="mw-heading mw-heading3"><h3 id="Locating_parameters_on_chart">Locating parameters on chart</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Psychrometrics&action=edit&section=18" title="Edit section: Locating parameters on chart"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a href="/wiki/Dry-bulb_temperature" title="Dry-bulb temperature">Dry-bulb temperature</a>: These lines are drawn straight, not always parallel to each other, and slightly inclined from the vertical position. This is the <i>t</i>–axis, the abscissa (horizontal) axis. Each line represents a constant temperature.</li></ul> <ul><li><a href="/wiki/Dew_point_temperature" class="mw-redirect" title="Dew point temperature">Dew point temperature</a>: From the state<sup class="noprint Inline-Template" style="margin-left:0.1em; white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Please_clarify" title="Wikipedia:Please clarify"><span title="state is undefined (December 2023)">clarification needed</span></a></i>]</sup> point follow the horizontal line of constant humidity ratio to the intercept of 100% RH, also known as the <i>saturation curve</i>. The dew point temperature is equal to the fully saturated dry bulb or wet bulb temperatures.</li></ul> <ul><li><a href="/wiki/Wet-bulb_temperature" title="Wet-bulb temperature">Wet-bulb temperature</a>: These lines are oblique lines that differ slightly from the enthalpy lines. They are identically straight but are not exactly parallel to each other. These intersect the saturation curve at DBT point.</li></ul> <ul><li><a href="/wiki/Relative_humidity" class="mw-redirect" title="Relative humidity">Relative humidity</a>: These hyperbolic lines are shown in intervals of 10%. The saturation curve is at 100% RH, while dry air is at 0% RH.</li></ul> <ul><li><a href="/wiki/Mixing_ratio" title="Mixing ratio">Humidity ratio</a>: These are the horizontal lines on the chart. Humidity ratio is usually expressed as mass of moisture per mass of dry air (pounds or kilograms of moisture per pound or kilogram of dry air, respectively). The range is from 0 for dry air up to 0.03 (lbmw/lbma) on the right hand <i>ω</i>-axis, the ordinate or vertical axis of the chart.</li></ul> <ul><li><a href="/wiki/Specific_enthalpy" class="mw-redirect" title="Specific enthalpy">Specific enthalpy</a>: These are oblique lines drawn diagonally downward from left to right across the chart that are parallel to each other. These are not parallel to wet bulb temperature lines.</li></ul> <ul><li><a href="/wiki/Specific_volume" title="Specific volume">Specific volume</a>: These are a family of equally spaced straight lines that are nearly parallel.</li></ul> <p>The region above the saturation curve is a two-phase region that represents a mixture of saturated moist air and liquid water, in thermal equilibrium. </p><p>The protractor on the upper left of the chart has two scales. The inner scale represents sensible-total heat ratio (SHF). The outer scale gives the ratio of enthalpy difference to humidity difference. This is used to establish the slope of a condition line between two processes. The horizontal component of the condition line is the change in sensible heat while the vertical component is the change in latent heat.<sup id="cite_ref-13" class="reference"><a href="#cite_note-13"><span class="cite-bracket">[</span>13<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-14" class="reference"><a href="#cite_note-14"><span class="cite-bracket">[</span>14<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-15" class="reference"><a href="#cite_note-15"><span class="cite-bracket">[</span>15<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="How_to_read_the_chart:_fundamental_examples">How to read the chart: fundamental examples</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Psychrometrics&action=edit&section=19" title="Edit section: How to read the chart: fundamental examples"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Psychrometric charts <sup id="cite_ref-16" class="reference"><a href="#cite_note-16"><span class="cite-bracket">[</span>16<span class="cite-bracket">]</span></a></sup> are available in SI (metric) and IP (U.S./Imperial) units. They are also available in low and high temperature ranges and for different pressures. </p> <ul><li>Determining relative humidity: The percent relative humidity can be located at the intersection of the vertical dry bulb and diagonally down sloping wet bulb temperature lines. Metric (SI): Using a dry bulb of 25 °C and a wet bulb of 20 °C, read the relative humidity at approximately 63.5%. U.S/Imperial (IP): Using a dry bulb of 77 °F and a wet bulb of 68 °F, read the relative humidity at approximately 63.5%. In this example the humidity ratio is 0.0126 kg water per kg dry air.</li> <li>Determining the effect of temperature change on relative humidity: For air of a fixed water composition or <i>moisture ratio</i>, find the starting relative humidity from the intersection of the wet and dry bulb temperature lines. Using the conditions from the previous example, the relative humidity at a different dry bulb temperatures can be found along the horizontal humidity ratio line of 0.0126, either in kg water per kg dry air or pounds water per pound dry air.</li></ul> <dl><dd>A common variation of this problem is determining the final humidity of air leaving an air conditioner evaporator coil then heated to a higher temperature. Assume that the temperature leaving the coil is 10°C (50°F) and is heated to room temperature (not mixed with room air), which is found by following the horizontal humidity ratio from the dew point or saturation line to the room dry bulb temperature line and reading the relative humidity. In typical practice the conditioned air is mixed with room air that is being infiltrated with outside air.</dd></dl> <ul><li>Determining the amount of water to be removed or added in lowering or raising relative humidity: This is the difference in humidity ratio between the initial and final conditions times the weight of dry air.</li></ul> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Mollier.pdf" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/5/59/Mollier.pdf/page1-350px-Mollier.pdf.jpg" decoding="async" width="350" height="270" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/5/59/Mollier.pdf/page1-525px-Mollier.pdf.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/5/59/Mollier.pdf/page1-700px-Mollier.pdf.jpg 2x" data-file-width="1650" data-file-height="1275" /></a><figcaption>Mollier Diagram (Chart), IP Units</figcaption></figure> <div class="mw-heading mw-heading3"><h3 id="Mollier_diagram">Mollier diagram</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Psychrometrics&action=edit&section=20" title="Edit section: Mollier diagram"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The "Mollier <i>i</i>-<i>x</i>" (Enthalpy – Humidity Mixing Ratio) diagram, developed by <a href="/wiki/Richard_Mollier" title="Richard Mollier">Richard Mollier</a> in 1923,<sup id="cite_ref-17" class="reference"><a href="#cite_note-17"><span class="cite-bracket">[</span>17<span class="cite-bracket">]</span></a></sup> is an alternative psychrometric chart, preferred by many users in Germany, Austria, Switzerland, the Netherlands, Belgium, France, Scandinavia, Eastern Europe, and Russia.<sup id="cite_ref-18" class="reference"><a href="#cite_note-18"><span class="cite-bracket">[</span>18<span class="cite-bracket">]</span></a></sup> </p><p>The underlying psychrometric parameter data for the psychrometric chart and the Mollier diagram are identical. At first glance there is little resemblance between the charts, but if the chart is rotated by ninety degrees and looked at in a mirror the resemblance becomes apparent. The Mollier diagram coordinates are enthalpy and humidity ratio. The enthalpy coordinate is <i>skewed</i> and the lines of constant enthalpy are parallel and evenly spaced. The ASHRAE psychrometric charts since 1961 use similar plotting coordinates. Some psychrometric charts use <i>dry-bulb temperature</i> and <i>humidity ratio</i> coordinates. </p> <div style="clear:both;" class=""></div> <div class="mw-heading mw-heading2"><h2 id="See_also">See also</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Psychrometrics&action=edit&section=21" title="Edit section: See also"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1184024115">.mw-parser-output .div-col{margin-top:0.3em;column-width:30em}.mw-parser-output .div-col-small{font-size:90%}.mw-parser-output .div-col-rules{column-rule:1px solid #aaa}.mw-parser-output .div-col dl,.mw-parser-output .div-col ol,.mw-parser-output .div-col ul{margin-top:0}.mw-parser-output .div-col li,.mw-parser-output .div-col dd{page-break-inside:avoid;break-inside:avoid-column}</style><div class="div-col"> <ul><li><a href="/wiki/Air" class="mw-redirect" title="Air">Air</a></li> <li><a href="/wiki/Air_conditioning" title="Air conditioning">Air conditioning</a></li> <li><a href="/wiki/Carnot_cycle" title="Carnot cycle">Carnot cycle</a></li> <li><a href="/wiki/Cromer_cycle" title="Cromer cycle">Cromer cycle</a></li> <li><a href="/wiki/Dalton%27s_law" title="Dalton's law">Dalton's law of Partial Pressures</a></li> <li><a href="/wiki/Dew_point" title="Dew point">Dew point</a></li> <li><a href="/wiki/Dry-bulb_temperature" title="Dry-bulb temperature">Dry-bulb temperature</a></li> <li><a href="/wiki/Evaporative_cooling" class="mw-redirect" title="Evaporative cooling">Evaporative cooling</a></li> <li><a href="/wiki/Humidity" title="Humidity">Humidity</a></li> <li><a href="/wiki/Operative_temperature" title="Operative temperature">Operative temperature</a></li> <li><a href="/wiki/Relative_humidity" class="mw-redirect" title="Relative humidity">Relative humidity</a></li> <li><a href="/wiki/Wet-bulb_temperature" title="Wet-bulb temperature">Wet-bulb temperature</a></li></ul> </div> <div class="mw-heading mw-heading2"><h2 id="References">References</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Psychrometrics&action=edit&section=22" title="Edit section: References"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1239543626">.mw-parser-output .reflist{margin-bottom:0.5em;list-style-type:decimal}@media screen{.mw-parser-output .reflist{font-size:90%}}.mw-parser-output .reflist .references{font-size:100%;margin-bottom:0;list-style-type:inherit}.mw-parser-output .reflist-columns-2{column-width:30em}.mw-parser-output .reflist-columns-3{column-width:25em}.mw-parser-output .reflist-columns{margin-top:0.3em}.mw-parser-output .reflist-columns ol{margin-top:0}.mw-parser-output .reflist-columns li{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .reflist-upper-alpha{list-style-type:upper-alpha}.mw-parser-output .reflist-upper-roman{list-style-type:upper-roman}.mw-parser-output .reflist-lower-alpha{list-style-type:lower-alpha}.mw-parser-output .reflist-lower-greek{list-style-type:lower-greek}.mw-parser-output .reflist-lower-roman{list-style-type:lower-roman}</style><div class="reflist"> <div class="mw-references-wrap mw-references-columns"><ol class="references"> <li id="cite_note-1"><span class="mw-cite-backlink"><b><a href="#cite_ref-1">^</a></b></span> <span class="reference-text"><style data-mw-deduplicate="TemplateStyles:r1238218222">.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/6/65/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/d/d6/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/a/aa/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("//upload.wikimedia.org/wikipedia/commons/4/4c/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}</style><cite id="CITEREFHenry_George_Liddell,_Robert_Scott" class="citation cs2">Henry George Liddell, Robert Scott, <a rel="nofollow" class="external text" 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ZVDI 67(9)</span> </li> <li id="cite_note-18"><span class="mw-cite-backlink"><b><a href="#cite_ref-18">^</a></b></span> <span class="reference-text">Todorovic, B., ASHRAE Transactions DA-07-024 (113-1), 2007</span> </li> </ol></div></div> <div class="mw-heading mw-heading2"><h2 id="External_links">External links</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Psychrometrics&action=edit&section=23" title="Edit section: External links"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1235681985">.mw-parser-output .side-box{margin:4px 0;box-sizing:border-box;border:1px solid #aaa;font-size:88%;line-height:1.25em;background-color:var(--background-color-interactive-subtle,#f8f9fa);display:flow-root}.mw-parser-output .side-box-abovebelow,.mw-parser-output .side-box-text{padding:0.25em 0.9em}.mw-parser-output .side-box-image{padding:2px 0 2px 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rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1126788409"> <div class="side-box-flex"> <div class="side-box-image"><span class="noviewer" typeof="mw:File"><span><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/9/99/Wiktionary-logo-en-v2.svg/40px-Wiktionary-logo-en-v2.svg.png" decoding="async" width="40" height="40" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/9/99/Wiktionary-logo-en-v2.svg/60px-Wiktionary-logo-en-v2.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/9/99/Wiktionary-logo-en-v2.svg/80px-Wiktionary-logo-en-v2.svg.png 2x" data-file-width="512" data-file-height="512" /></span></span></div> <div class="side-box-text plainlist">Look up <i><b><a href="https://en.wiktionary.org/wiki/psychrometrics" class="extiw" title="wiktionary:psychrometrics">psychrometrics</a></b></i> or <i><b><a href="https://en.wiktionary.org/wiki/psychrometry" class="extiw" title="wiktionary:psychrometry">psychrometry</a></b></i> in Wiktionary, the free dictionary.</div></div> </div> <ul><li><a rel="nofollow" class="external text" href="http://wcec.ucdavis.edu/resources/software-resource-applications/">Western Cooling Efficiency Center</a> Psych: An Open Source Psychrometric Plug-in for Microsoft Excel by Kevin Brown.</li> <li><a rel="nofollow" class="external text" href="http://xchanger.com/calculators/psychrometric-temperaturehumidity-calculator">Xchanger Inc, webpage</a> Calculator for humidity, dew point, mass flows & heat flux for variable pressure systems with compressors, blowers, vacuum pumps and heat exchangers.</li> <li><a rel="nofollow" class="external text" href="https://web.archive.org/web/20070305134609/http://www.issi1.com/corwin/calculator/vapor.html">Corwin's Calculators</a> Calculator for humidity, dew point.</li> <li><a rel="nofollow" class="external text" href="http://www.powerknot.com/how-to-read-and-use-a-psychrometric-chart.html">How to read and use a psychrometric chart</a></li> <li><a rel="nofollow" class="external text" href="https://www.flycarpet.net/en/psyonline">Free Online Interactive Psychrometric Chart</a></li> <li><a rel="nofollow" class="external text" href="https://www.psychrosim.com">Psychrometric Chart Calculator and Sketcher</a></li></ul> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><style data-mw-deduplicate="TemplateStyles:r1236075235">.mw-parser-output .navbox{box-sizing:border-box;border:1px solid #a2a9b1;width:100%;clear:both;font-size:88%;text-align:center;padding:1px;margin:1em auto 0}.mw-parser-output .navbox .navbox{margin-top:0}.mw-parser-output .navbox+.navbox,.mw-parser-output .navbox+.navbox-styles+.navbox{margin-top:-1px}.mw-parser-output .navbox-inner,.mw-parser-output .navbox-subgroup{width:100%}.mw-parser-output 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colspan="2"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239400231"><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:HVAC" title="Template:HVAC"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:HVAC" title="Template talk:HVAC"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:HVAC" title="Special:EditPage/Template:HVAC"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Heating,_ventilation,_and_air_conditioning" style="font-size:114%;margin:0 4em"><a href="/wiki/Heating,_ventilation,_and_air_conditioning" title="Heating, ventilation, and air conditioning">Heating, ventilation, and air conditioning</a></div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%">Fundamental <br />concepts</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0;text-align: middle;"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Air_changes_per_hour" title="Air changes per hour">Air changes per hour</a></li> <li><a href="/wiki/Bake-out" title="Bake-out">Bake-out</a></li> <li><a href="/wiki/Building_envelope" title="Building envelope">Building envelope</a></li> <li><a href="/wiki/Convection" title="Convection">Convection</a></li> <li><a href="/wiki/Dilution_(equation)" title="Dilution (equation)">Dilution</a></li> <li><a href="/wiki/Domestic_energy_consumption" title="Domestic energy consumption">Domestic energy consumption</a></li> <li><a href="/wiki/Enthalpy" title="Enthalpy">Enthalpy</a></li> <li><a href="/wiki/Fluid_dynamics" title="Fluid dynamics">Fluid dynamics</a></li> <li><a href="/wiki/Gas_compressor" class="mw-redirect" title="Gas compressor">Gas compressor</a></li> <li><a href="/wiki/Heat_pump_and_refrigeration_cycle" title="Heat pump and refrigeration cycle">Heat pump and refrigeration cycle</a></li> <li><a href="/wiki/Heat_transfer" title="Heat transfer">Heat transfer</a></li> <li><a href="/wiki/Humidity" title="Humidity">Humidity</a></li> <li><a href="/wiki/Infiltration_(HVAC)" title="Infiltration (HVAC)">Infiltration</a></li> <li><a href="/wiki/Latent_heat" title="Latent heat">Latent heat</a></li> <li><a href="/wiki/Noise_control" title="Noise control">Noise control</a></li> <li><a href="/wiki/Outgassing" title="Outgassing">Outgassing</a></li> <li><a href="/wiki/Particulates" title="Particulates">Particulates</a></li> <li><a class="mw-selflink selflink">Psychrometrics</a></li> <li><a href="/wiki/Sensible_heat" title="Sensible heat">Sensible heat</a></li> <li><a href="/wiki/Stack_effect" title="Stack effect">Stack effect</a></li> <li><a href="/wiki/Thermal_comfort" title="Thermal comfort">Thermal comfort</a></li> <li><a href="/wiki/Thermal_destratification" title="Thermal destratification">Thermal destratification</a></li> <li><a href="/wiki/Thermal_mass" title="Thermal mass">Thermal mass</a></li> <li><a href="/wiki/Thermodynamics" title="Thermodynamics">Thermodynamics</a></li> <li><a href="/wiki/Vapour_pressure_of_water" title="Vapour pressure of water">Vapour pressure of water</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Technology</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0;text-align: middle;"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Absorption-compression_heat_pump" title="Absorption-compression heat pump">Absorption-compression heat pump</a></li> <li><a href="/wiki/Absorption_refrigerator" title="Absorption refrigerator">Absorption refrigerator</a></li> <li><a href="/wiki/Air_barrier" title="Air barrier">Air barrier</a></li> <li><a href="/wiki/Air_conditioning" title="Air conditioning">Air conditioning</a></li> <li><a href="/wiki/Antifreeze" title="Antifreeze">Antifreeze</a></li> <li><a href="/wiki/Automobile_air_conditioning" class="mw-redirect" title="Automobile air conditioning">Automobile air conditioning</a></li> <li><a href="/wiki/Autonomous_building" title="Autonomous building">Autonomous building</a></li> <li><a href="/wiki/Building_insulation_material" title="Building insulation material">Building insulation materials</a></li> <li><a href="/wiki/Central_heating" title="Central heating">Central heating</a></li> <li><a href="/wiki/Central_solar_heating" title="Central solar heating">Central solar heating</a></li> <li><a href="/wiki/Chilled_beam" title="Chilled beam">Chilled beam</a></li> <li><a href="/wiki/Chilled_water" title="Chilled water">Chilled water</a></li> <li><a href="/wiki/Constant_air_volume" title="Constant air volume">Constant air volume</a> (CAV)</li> <li><a href="/wiki/Coolant" title="Coolant">Coolant</a></li> <li><a href="/wiki/Cross_ventilation" title="Cross ventilation">Cross ventilation</a></li> <li><a href="/wiki/Dedicated_outdoor_air_system" title="Dedicated outdoor air system">Dedicated outdoor air system</a> (DOAS)</li> <li><a href="/wiki/Deep_water_source_cooling" title="Deep water source cooling">Deep water source cooling</a></li> <li><a href="/wiki/Demand_controlled_ventilation" title="Demand controlled ventilation">Demand controlled ventilation</a> (DCV)</li> <li><a href="/wiki/Displacement_ventilation" title="Displacement ventilation">Displacement ventilation</a></li> <li><a href="/wiki/District_cooling" title="District cooling">District cooling</a></li> <li><a href="/wiki/District_heating" title="District heating">District heating</a></li> <li><a href="/wiki/Electric_heating" title="Electric heating">Electric heating</a></li> <li><a href="/wiki/Energy_recovery_ventilation" class="mw-redirect" title="Energy recovery ventilation">Energy recovery ventilation</a> (ERV)</li> <li><a href="/wiki/Firestop" title="Firestop">Firestop</a></li> <li><a href="/wiki/Forced-air" title="Forced-air">Forced-air</a></li> <li><a href="/wiki/Forced-air_gas" title="Forced-air gas">Forced-air gas</a></li> <li><a href="/wiki/Free_cooling" title="Free cooling">Free cooling</a></li> <li><a href="/wiki/Heat_recovery_ventilation" title="Heat recovery ventilation">Heat recovery ventilation</a> (HRV)</li> <li><a href="/wiki/Hybrid_heat" title="Hybrid heat">Hybrid heat</a></li> <li><a href="/wiki/Hydronics" title="Hydronics">Hydronics</a></li> <li><a href="/wiki/Ice_storage_air_conditioning" title="Ice storage air conditioning">Ice storage air conditioning</a></li> <li><a href="/wiki/Kitchen_ventilation" title="Kitchen ventilation">Kitchen ventilation</a></li> <li><a href="/wiki/Mixed-mode_ventilation" title="Mixed-mode ventilation">Mixed-mode ventilation</a></li> <li><a href="/wiki/Microgeneration" title="Microgeneration">Microgeneration</a></li> <li><a href="/wiki/Passive_cooling" title="Passive cooling">Passive cooling</a></li> <li><a href="/wiki/Passive_daytime_radiative_cooling" title="Passive daytime radiative cooling">Passive daytime radiative cooling</a></li> <li><a href="/wiki/Passive_house" title="Passive house">Passive house</a></li> <li><a href="/wiki/Passive_ventilation" title="Passive ventilation">Passive ventilation</a></li> <li><a href="/wiki/Radiant_heating_and_cooling" title="Radiant heating and cooling">Radiant heating and cooling</a></li> <li><a href="/wiki/Radiant_cooling" class="mw-redirect" title="Radiant cooling">Radiant cooling</a></li> <li><a href="/wiki/Radiant_heating" class="mw-redirect" title="Radiant heating">Radiant heating</a></li> <li><a href="/wiki/Radon_mitigation" title="Radon mitigation">Radon mitigation</a></li> <li><a href="/wiki/Refrigeration" title="Refrigeration">Refrigeration</a></li> <li><a href="/wiki/Renewable_heat" title="Renewable heat">Renewable heat</a></li> <li><a href="/wiki/Room_air_distribution" title="Room air distribution">Room air distribution</a></li> <li><a href="/wiki/Solar_air_heat" title="Solar air heat">Solar air heat</a></li> <li><a href="/wiki/Solar_combisystem" title="Solar combisystem">Solar combisystem</a></li> <li><a href="/wiki/Solar_cooling" class="mw-redirect" title="Solar cooling">Solar cooling</a></li> <li><a href="/wiki/Solar_heating" class="mw-redirect" title="Solar heating">Solar heating</a></li> <li><a href="/wiki/Thermal_insulation" title="Thermal insulation">Thermal insulation</a></li> <li><a href="/wiki/Thermosiphon" title="Thermosiphon">Thermosiphon</a></li> <li><a href="/wiki/Underfloor_air_distribution" title="Underfloor air distribution">Underfloor air distribution</a></li> <li><a href="/wiki/Underfloor_heating" title="Underfloor heating">Underfloor heating</a></li> <li><a href="/wiki/Vapor_barrier" title="Vapor barrier">Vapor barrier</a></li> <li><a href="/wiki/Vapor-compression_refrigeration" title="Vapor-compression refrigeration">Vapor-compression refrigeration</a> (VCRS)</li> <li><a href="/wiki/Variable_air_volume" title="Variable air volume">Variable air volume</a> (VAV)</li> <li><a href="/wiki/Variable_refrigerant_flow" title="Variable refrigerant flow">Variable refrigerant flow</a> (VRF)</li> <li><a href="/wiki/Ventilation_(architecture)" title="Ventilation (architecture)">Ventilation</a></li> <li><a href="/wiki/Water_heat_recycling" title="Water heat recycling">Water heat recycling</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Components</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0;text-align: middle;"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Air_conditioner_inverter" class="mw-redirect" title="Air conditioner inverter">Air conditioner inverter</a></li> <li><a href="/wiki/Air_door" title="Air door">Air door</a></li> <li><a href="/wiki/Air_filter" title="Air filter">Air filter</a></li> <li><a href="/wiki/Air_handler" title="Air handler">Air handler</a></li> <li><a href="/wiki/Air_ioniser" title="Air ioniser">Air ionizer</a></li> <li><a href="/wiki/Air-mixing_plenum" title="Air-mixing plenum">Air-mixing plenum</a></li> <li><a href="/wiki/Air_purifier" title="Air purifier">Air purifier</a></li> <li><a href="/wiki/Air_source_heat_pump" title="Air source heat pump">Air source heat pump</a></li> <li><a href="/wiki/Attic_fan" title="Attic fan">Attic fan</a></li> <li><a href="/wiki/Automatic_balancing_valve" title="Automatic balancing valve">Automatic balancing valve</a></li> <li><a href="/wiki/Back_boiler" title="Back boiler">Back boiler</a></li> <li><a href="/wiki/Barrier_pipe" title="Barrier pipe">Barrier pipe</a></li> <li><a href="/wiki/Blast_damper" title="Blast damper">Blast damper</a></li> <li><a href="/wiki/Boiler" title="Boiler">Boiler</a></li> <li><a href="/wiki/Centrifugal_fan" title="Centrifugal fan">Centrifugal fan</a></li> <li><a href="/wiki/Ceramic_heater" title="Ceramic heater">Ceramic heater</a></li> <li><a href="/wiki/Chiller" title="Chiller">Chiller</a></li> <li><a href="/wiki/Condensate_pump" title="Condensate pump">Condensate pump</a></li> <li><a href="/wiki/Condenser_(heat_transfer)" title="Condenser (heat transfer)">Condenser</a></li> <li><a href="/wiki/Condensing_boiler" title="Condensing boiler">Condensing boiler</a></li> <li><a href="/wiki/Convection_heater" title="Convection heater">Convection heater</a></li> <li><a href="/wiki/Compressor" title="Compressor">Compressor</a></li> <li><a href="/wiki/Cooling_tower" title="Cooling tower">Cooling tower</a></li> <li><a href="/wiki/Damper_(flow)" title="Damper (flow)">Damper</a></li> <li><a href="/wiki/Dehumidifier" title="Dehumidifier">Dehumidifier</a></li> <li><a href="/wiki/Duct_(flow)" title="Duct (flow)">Duct</a></li> <li><a href="/wiki/Economizer" title="Economizer">Economizer</a></li> <li><a href="/wiki/Electrostatic_precipitator" title="Electrostatic precipitator">Electrostatic precipitator</a></li> <li><a href="/wiki/Evaporative_cooler" title="Evaporative cooler">Evaporative cooler</a></li> <li><a href="/wiki/Evaporator" title="Evaporator">Evaporator</a></li> <li><a href="/wiki/Exhaust_hood" class="mw-redirect" title="Exhaust hood">Exhaust hood</a></li> <li><a href="/wiki/Expansion_tank" title="Expansion tank">Expansion tank</a></li> <li><a href="/wiki/Fan_(machine)" title="Fan (machine)">Fan</a></li> <li><a href="/wiki/Fan_coil_unit" title="Fan coil unit">Fan coil unit</a></li> <li><a href="/wiki/Fan_filter_unit" title="Fan filter unit">Fan filter unit</a></li> <li><a href="/wiki/Fan_heater" title="Fan heater">Fan heater</a></li> <li><a href="/wiki/Fire_damper" title="Fire damper">Fire damper</a></li> <li><a href="/wiki/Fireplace" title="Fireplace">Fireplace</a></li> <li><a href="/wiki/Fireplace_insert" title="Fireplace insert">Fireplace insert</a></li> <li><a href="/wiki/Freeze_stat" title="Freeze stat">Freeze stat</a></li> <li><a href="/wiki/Flue" title="Flue">Flue</a></li> <li><a href="/wiki/Freon" title="Freon">Freon</a></li> <li><a href="/wiki/Fume_hood" title="Fume hood">Fume hood</a></li> <li><a href="/wiki/Furnace_(house_heating)" class="mw-redirect" title="Furnace (house heating)">Furnace</a></li> <li><a href="/wiki/Gas_compressor" class="mw-redirect" title="Gas compressor">Gas compressor</a></li> <li><a href="/wiki/Gas_heater" title="Gas heater">Gas heater</a></li> <li><a href="/wiki/Gasoline_heater" title="Gasoline heater">Gasoline heater</a></li> <li><a href="/wiki/Grease_duct" title="Grease duct">Grease duct</a></li> <li><a href="/wiki/Grille_(architecture)" title="Grille (architecture)">Grille</a></li> <li><a href="/wiki/Ground-coupled_heat_exchanger" title="Ground-coupled heat exchanger">Ground-coupled heat exchanger</a></li> <li><a href="/wiki/Ground_source_heat_pump" title="Ground source heat pump">Ground source heat pump</a></li> <li><a href="/wiki/Heat_exchanger" title="Heat exchanger">Heat exchanger</a></li> <li><a href="/wiki/Heat_pipe" title="Heat pipe">Heat pipe</a></li> <li><a href="/wiki/Heat_pump" title="Heat pump">Heat pump</a></li> <li><a href="/wiki/Heating_film" title="Heating film">Heating film</a></li> <li><a href="/wiki/Heating_system" title="Heating system">Heating system</a></li> <li><a href="/wiki/HEPA" title="HEPA">HEPA</a></li> <li><a href="/wiki/High_efficiency_glandless_circulating_pump" title="High efficiency glandless circulating pump">High efficiency glandless circulating pump</a></li> <li><a href="/wiki/High-pressure_cut-off_switch" class="mw-redirect" title="High-pressure cut-off switch">High-pressure cut-off switch</a></li> <li><a href="/wiki/Humidifier" title="Humidifier">Humidifier</a></li> <li><a href="/wiki/Infrared_heater" title="Infrared heater">Infrared heater</a></li> <li><a href="/wiki/Inverter_compressor" title="Inverter compressor">Inverter compressor</a></li> <li><a href="/wiki/Kerosene_heater" title="Kerosene heater">Kerosene heater</a></li> <li><a href="/wiki/Louver" title="Louver">Louver</a></li> <li><a href="/wiki/Mechanical_room" title="Mechanical room">Mechanical room</a></li> <li><a href="/wiki/Oil_heater" title="Oil heater">Oil heater</a></li> <li><a href="/wiki/Packaged_terminal_air_conditioner" title="Packaged terminal air conditioner">Packaged terminal air conditioner</a></li> <li><a href="/wiki/Plenum_space" title="Plenum space">Plenum space</a></li> <li><a href="/wiki/Pressurisation_ductwork" title="Pressurisation ductwork">Pressurisation ductwork</a></li> <li><a href="/wiki/Process_duct_work" title="Process duct work">Process duct work</a></li> <li><a href="/wiki/Radiator_(heating)" title="Radiator (heating)">Radiator</a></li> <li><a href="/wiki/Radiator_reflector" title="Radiator reflector">Radiator reflector</a></li> <li><a href="/wiki/Recuperator" title="Recuperator">Recuperator</a></li> <li><a href="/wiki/Refrigerant" title="Refrigerant">Refrigerant</a></li> <li><a href="/wiki/Register_(air_and_heating)" title="Register (air and heating)">Register</a></li> <li><a href="/wiki/Reversing_valve" title="Reversing valve">Reversing valve</a></li> <li><a href="/wiki/Run-around_coil" title="Run-around coil">Run-around coil</a></li> <li><a href="/wiki/Sail_switch" title="Sail switch">Sail switch</a></li> <li><a href="/wiki/Scroll_compressor" title="Scroll compressor">Scroll compressor</a></li> <li><a href="/wiki/Solar_chimney" title="Solar chimney">Solar chimney</a></li> <li><a href="/wiki/Solar-assisted_heat_pump" title="Solar-assisted heat pump">Solar-assisted heat pump</a></li> <li><a href="/wiki/Space_heater" title="Space heater">Space heater</a></li> <li><a href="/wiki/Smoke_canopy" title="Smoke canopy">Smoke canopy</a></li> <li><a href="/wiki/Smoke_damper" title="Smoke damper">Smoke damper</a></li> <li><a href="/wiki/Smoke_exhaust_ductwork" title="Smoke exhaust ductwork">Smoke exhaust ductwork</a></li> <li><a href="/wiki/Thermal_expansion_valve" title="Thermal expansion valve">Thermal expansion valve</a></li> <li><a href="/wiki/Thermal_wheel" title="Thermal wheel">Thermal wheel</a></li> <li><a href="/wiki/Thermostatic_radiator_valve" title="Thermostatic radiator valve">Thermostatic radiator valve</a></li> <li><a href="/wiki/Trickle_vent" title="Trickle vent">Trickle vent</a></li> <li><a href="/wiki/Trombe_wall" title="Trombe wall">Trombe wall</a></li> <li><a href="/wiki/TurboSwing" title="TurboSwing">TurboSwing</a></li> <li><a href="/wiki/Turning_vanes_(HVAC)" title="Turning vanes (HVAC)">Turning vanes</a></li> <li><a href="/wiki/Ultra-low_particulate_air" title="Ultra-low particulate air">Ultra-low particulate air</a> (ULPA)</li> <li><a href="/wiki/Whole-house_fan" title="Whole-house fan">Whole-house fan</a></li> <li><a href="/wiki/Windcatcher" title="Windcatcher">Windcatcher</a></li> <li><a href="/wiki/Wood-burning_stove" title="Wood-burning stove">Wood-burning stove</a></li> <li><a href="/wiki/Zone_valve" title="Zone valve">Zone valve</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Measurement<br />and control</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0;text-align: middle;"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Air_flow_meter" title="Air flow meter">Air flow meter</a></li> <li><a href="/wiki/Aquastat" title="Aquastat">Aquastat</a></li> <li><a href="/wiki/BACnet" title="BACnet">BACnet</a></li> <li><a href="/wiki/Blower_door" title="Blower door">Blower door</a></li> <li><a href="/wiki/Building_automation" title="Building automation">Building automation</a></li> <li><a href="/wiki/Carbon_dioxide_sensor" title="Carbon dioxide sensor">Carbon dioxide sensor</a></li> <li><a href="/wiki/Clean_air_delivery_rate" title="Clean air delivery rate">Clean air delivery rate</a> (CADR)</li> <li><a href="/wiki/Control_valve" title="Control valve">Control valve</a></li> <li><a href="/wiki/Gas_detector" title="Gas detector">Gas detector</a></li> <li><a href="/wiki/Home_energy_monitor" title="Home energy monitor">Home energy monitor</a></li> <li><a href="/wiki/Humidistat" title="Humidistat">Humidistat</a></li> <li><a href="/wiki/HVAC_control_system" title="HVAC control system">HVAC control system</a></li> <li><a href="/wiki/Infrared_thermometer" title="Infrared thermometer">Infrared thermometer</a></li> <li><a href="/wiki/Intelligent_buildings" class="mw-redirect" title="Intelligent buildings">Intelligent buildings</a></li> <li><a href="/wiki/LonWorks" title="LonWorks">LonWorks</a></li> <li><a href="/wiki/Minimum_efficiency_reporting_value" title="Minimum efficiency reporting value">Minimum efficiency reporting value</a> (MERV)</li> <li><a href="/wiki/Normal_temperature_and_pressure" class="mw-redirect" title="Normal temperature and pressure">Normal temperature and pressure</a> (NTP)</li> <li><a href="/wiki/OpenTherm" title="OpenTherm">OpenTherm</a></li> <li><a href="/wiki/Programmable_communicating_thermostat" title="Programmable communicating thermostat">Programmable communicating thermostat</a></li> <li><a href="/wiki/Programmable_thermostat" title="Programmable thermostat">Programmable thermostat</a></li> <li><a class="mw-selflink selflink">Psychrometrics</a></li> <li><a href="/wiki/Room_temperature" title="Room temperature">Room temperature</a></li> <li><a href="/wiki/Smart_thermostat" title="Smart thermostat">Smart thermostat</a></li> <li><a href="/wiki/Standard_temperature_and_pressure" title="Standard temperature and pressure">Standard temperature and pressure</a> (STP)</li> <li><a href="/wiki/Thermographic_camera" class="mw-redirect" title="Thermographic camera">Thermographic camera</a></li> <li><a href="/wiki/Thermostat" title="Thermostat">Thermostat</a></li> <li><a href="/wiki/Thermostatic_radiator_valve" title="Thermostatic radiator valve">Thermostatic radiator valve</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Professions,<br />trades,<br />and services</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0;text-align: middle;"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Architectural_acoustics" title="Architectural acoustics">Architectural acoustics</a></li> <li><a href="/wiki/Architectural_engineering" title="Architectural engineering">Architectural engineering</a></li> <li><a href="/wiki/Architectural_technologist" title="Architectural technologist">Architectural technologist</a></li> <li><a href="/wiki/Building_services_engineering" title="Building services engineering">Building services engineering</a></li> <li><a href="/wiki/Building_information_modeling" title="Building information modeling">Building information modeling</a> (BIM)</li> <li><a href="/wiki/Deep_energy_retrofit" title="Deep energy retrofit">Deep energy retrofit</a></li> <li><a href="/wiki/Duct_cleaning" class="mw-redirect" title="Duct cleaning">Duct cleaning</a></li> <li><a href="/wiki/Duct_leakage_testing" title="Duct leakage testing">Duct leakage testing</a></li> <li><a href="/wiki/Environmental_engineering" title="Environmental engineering">Environmental engineering</a></li> <li><a href="/wiki/Hydronic_balancing" title="Hydronic balancing">Hydronic balancing</a></li> <li><a href="/wiki/Kitchen_exhaust_cleaning" title="Kitchen exhaust cleaning">Kitchen exhaust cleaning</a></li> <li><a href="/wiki/Mechanical_engineering" title="Mechanical engineering">Mechanical engineering</a></li> <li><a href="/wiki/Mechanical,_electrical,_and_plumbing" title="Mechanical, electrical, and plumbing">Mechanical, electrical, and plumbing</a></li> <li><a href="/wiki/Mold_growth,_assessment,_and_remediation" class="mw-redirect" title="Mold growth, assessment, and remediation">Mold growth, assessment, and remediation</a></li> <li><a href="/wiki/Refrigerant_reclamation" title="Refrigerant reclamation">Refrigerant reclamation</a></li> <li><a href="/wiki/Testing,_adjusting,_balancing" title="Testing, adjusting, balancing">Testing, adjusting, balancing</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Industry <br />organizations</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0;text-align: middle;"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Air_Conditioning,_Heating_and_Refrigeration_Institute" title="Air Conditioning, Heating and Refrigeration Institute">AHRI</a></li> <li><a href="/wiki/Air_Movement_and_Control_Association" title="Air Movement and Control Association">AMCA</a></li> <li><a href="/wiki/ASHRAE" title="ASHRAE">ASHRAE</a></li> <li><a href="/wiki/ASTM_International" title="ASTM International">ASTM International</a></li> <li><a href="/wiki/Building_Research_Establishment" title="Building Research Establishment">BRE</a></li> <li><a href="/wiki/BSRIA" title="BSRIA">BSRIA</a></li> <li><a href="/wiki/Chartered_Institution_of_Building_Services_Engineers" title="Chartered Institution of Building Services Engineers">CIBSE</a></li> <li><a href="/wiki/Institute_of_Refrigeration" title="Institute of Refrigeration">Institute of Refrigeration</a></li> <li><a href="/wiki/International_Institute_of_Refrigeration" title="International Institute of Refrigeration">IIR</a></li> <li><a href="/wiki/Leadership_in_Energy_and_Environmental_Design" class="mw-redirect" title="Leadership in Energy and Environmental Design">LEED</a></li> <li><a href="/wiki/Sheet_Metal_and_Air_Conditioning_Contractors%27_National_Association" title="Sheet Metal and Air Conditioning Contractors' National Association">SMACNA</a></li> <li><a href="/wiki/Uniform_Mechanical_Code" title="Uniform Mechanical Code">UMC</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Health and safety</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0;text-align: middle;"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Indoor_air_quality" title="Indoor air quality">Indoor air quality</a> (IAQ)</li> <li><a href="/wiki/Passive_smoking" title="Passive smoking">Passive smoking</a></li> <li><a href="/wiki/Sick_building_syndrome" title="Sick building syndrome">Sick building syndrome</a> (SBS)</li> <li><a href="/wiki/Volatile_organic_compound" title="Volatile organic compound">Volatile organic compound</a> (VOC)</li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">See also</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0;text-align: middle;"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/ASHRAE_Handbook" title="ASHRAE Handbook">ASHRAE Handbook</a></li> <li><a href="/wiki/Building_science" title="Building science">Building science</a></li> <li><a href="/wiki/Fireproofing" title="Fireproofing">Fireproofing</a></li> <li><a href="/wiki/Glossary_of_HVAC_terms" title="Glossary of HVAC terms">Glossary of HVAC terms</a></li> <li><a href="/wiki/Warm_Spaces" title="Warm Spaces">Warm Spaces</a></li> <li><a href="/wiki/World_Refrigeration_Day" title="World Refrigeration Day">World Refrigeration Day</a></li> <li><a href="/wiki/Template:Home_automation" title="Template:Home automation">Template:Home automation</a></li> <li><a href="/wiki/Template:Solar_energy" title="Template:Solar energy">Template:Solar energy</a></li></ul> </div></td></tr></tbody></table></div>    </div><noscript><img src="https://login.wikimedia.org/wiki/Special:CentralAutoLogin/start?type=1x1" alt="" width="1" height="1" style="border: none; position: absolute;"></noscript> <div class="printfooter" data-nosnippet="">Retrieved from "<a dir="ltr" href="https://en.wikipedia.org/w/index.php?title=Psychrometrics&oldid=1252197041">https://en.wikipedia.org/w/index.php?title=Psychrometrics&oldid=1252197041</a>"</div></div> <div id="catlinks" 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