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<span>Types of hydronic system</span> </div> </a> <button aria-controls="toc-Types_of_hydronic_system-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 Types of hydronic system subsection</span> </button> <ul id="toc-Types_of_hydronic_system-sublist" class="vector-toc-list"> <li id="toc-Basic_types" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Basic_types"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.1</span> <span>Basic types</span> </div> </a> <ul id="toc-Basic_types-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Classification" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Classification"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.2</span> <span>Classification</span> </div> </a> <ul id="toc-Classification-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Piping_arrangements" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Piping_arrangements"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.3</span> <span>Piping arrangements</span> </div> </a> <ul id="toc-Piping_arrangements-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Single-pipe_steam" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Single-pipe_steam"> <div class="vector-toc-text"> <span class="vector-toc-numb">3</span> <span>Single-pipe steam</span> </div> </a> <ul id="toc-Single-pipe_steam-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Two-pipe_steam_systems" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Two-pipe_steam_systems"> <div class="vector-toc-text"> <span class="vector-toc-numb">4</span> <span>Two-pipe steam systems</span> </div> </a> <ul id="toc-Two-pipe_steam_systems-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Two-pipe_direct_return_system" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Two-pipe_direct_return_system"> <div class="vector-toc-text"> <span class="vector-toc-numb">5</span> <span>Two-pipe direct return system</span> </div> </a> <button aria-controls="toc-Two-pipe_direct_return_system-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 Two-pipe direct return system subsection</span> </button> <ul id="toc-Two-pipe_direct_return_system-sublist" class="vector-toc-list"> <li id="toc-Advantages" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Advantages"> <div class="vector-toc-text"> <span class="vector-toc-numb">5.1</span> <span>Advantages</span> </div> </a> <ul id="toc-Advantages-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Disadvantages" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Disadvantages"> <div class="vector-toc-text"> <span class="vector-toc-numb">5.2</span> <span>Disadvantages</span> </div> </a> <ul id="toc-Disadvantages-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Two-pipe_reverse_return_system" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Two-pipe_reverse_return_system"> <div class="vector-toc-text"> <span class="vector-toc-numb">6</span> <span>Two-pipe reverse return system</span> </div> </a> <button aria-controls="toc-Two-pipe_reverse_return_system-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 Two-pipe reverse return system subsection</span> </button> <ul id="toc-Two-pipe_reverse_return_system-sublist" class="vector-toc-list"> <li id="toc-Advantages_2" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Advantages_2"> <div class="vector-toc-text"> <span class="vector-toc-numb">6.1</span> <span>Advantages</span> </div> </a> <ul id="toc-Advantages_2-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Disadvantages_2" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Disadvantages_2"> <div class="vector-toc-text"> <span class="vector-toc-numb">6.2</span> <span>Disadvantages</span> </div> </a> <ul id="toc-Disadvantages_2-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Water_loops" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Water_loops"> <div class="vector-toc-text"> <span class="vector-toc-numb">7</span> <span>Water loops</span> </div> </a> <ul id="toc-Water_loops-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Improved_efficiency_and_operating_costs" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Improved_efficiency_and_operating_costs"> <div class="vector-toc-text"> <span class="vector-toc-numb">8</span> <span>Improved efficiency and operating costs</span> </div> </a> <ul id="toc-Improved_efficiency_and_operating_costs-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Balancing" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Balancing"> <div class="vector-toc-text"> <span class="vector-toc-numb">9</span> <span>Balancing</span> </div> </a> <ul id="toc-Balancing-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Boiler_water_treatment" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Boiler_water_treatment"> <div class="vector-toc-text"> <span class="vector-toc-numb">10</span> <span>Boiler water treatment</span> </div> </a> <ul id="toc-Boiler_water_treatment-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Air_elimination" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Air_elimination"> <div class="vector-toc-text"> <span class="vector-toc-numb">11</span> <span>Air elimination</span> </div> </a> <button aria-controls="toc-Air_elimination-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 Air elimination subsection</span> </button> <ul id="toc-Air_elimination-sublist" class="vector-toc-list"> <li id="toc-Water-loop_system" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Water-loop_system"> <div class="vector-toc-text"> <span class="vector-toc-numb">11.1</span> <span>Water-loop system</span> </div> </a> <ul id="toc-Water-loop_system-sublist" class="vector-toc-list"> <li id="toc-Free_air" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#Free_air"> <div class="vector-toc-text"> <span class="vector-toc-numb">11.1.1</span> <span>Free air</span> </div> </a> <ul id="toc-Free_air-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Entrained_air" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#Entrained_air"> <div class="vector-toc-text"> <span class="vector-toc-numb">11.1.2</span> <span>Entrained air</span> </div> </a> <ul id="toc-Entrained_air-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Dissolved_air" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#Dissolved_air"> <div class="vector-toc-text"> <span class="vector-toc-numb">11.1.3</span> <span>Dissolved air</span> </div> </a> <ul id="toc-Dissolved_air-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> </ul> </li> <li id="toc-Accommodating_thermal_expansion" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Accommodating_thermal_expansion"> <div class="vector-toc-text"> <span class="vector-toc-numb">12</span> <span>Accommodating thermal expansion</span> </div> </a> <ul id="toc-Accommodating_thermal_expansion-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Automatic_fill_mechanisms" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Automatic_fill_mechanisms"> <div class="vector-toc-text"> <span class="vector-toc-numb">13</span> <span>Automatic fill mechanisms</span> </div> </a> <ul id="toc-Automatic_fill_mechanisms-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Safety_mechanisms" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Safety_mechanisms"> <div class="vector-toc-text"> <span class="vector-toc-numb">14</span> <span>Safety mechanisms</span> </div> </a> <ul id="toc-Safety_mechanisms-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Typical_schematic_with_control_devices_shown" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Typical_schematic_with_control_devices_shown"> <div class="vector-toc-text"> <span class="vector-toc-numb">15</span> <span>Typical schematic with control devices shown</span> </div> </a> <ul id="toc-Typical_schematic_with_control_devices_shown-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-See_also" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#See_also"> <div class="vector-toc-text"> <span class="vector-toc-numb">16</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"> <a class="vector-toc-link" href="#References"> <div class="vector-toc-text"> <span class="vector-toc-numb">17</span> <span>References</span> </div> </a> <ul id="toc-References-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 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</div> </div> </nav> <h1 id="firstHeading" class="firstHeading mw-first-heading"><span class="mw-page-title-main">Hydronics</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. 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href="https://be.wikipedia.org/wiki/%D0%A6%D0%B5%D0%BF%D0%BB%D0%B0%D0%B2%D0%B0%D1%8F_%D1%81%D0%B5%D1%82%D0%BA%D0%B0" title="Цеплавая сетка – Belarusian" lang="be" hreflang="be" data-title="Цеплавая сетка" data-language-autonym="Беларуская" data-language-local-name="Belarusian" class="interlanguage-link-target"><span>Беларуская</span></a></li><li class="interlanguage-link interwiki-cs mw-list-item"><a href="https://cs.wikipedia.org/wiki/Teplovod" title="Teplovod – Czech" lang="cs" hreflang="cs" data-title="Teplovod" data-language-autonym="Čeština" data-language-local-name="Czech" class="interlanguage-link-target"><span>Čeština</span></a></li><li class="interlanguage-link interwiki-hy mw-list-item"><a href="https://hy.wikipedia.org/wiki/%D5%8B%D5%A5%D6%80%D5%B4%D5%A1%D5%B5%D5%AB%D5%B6_%D6%81%D5%A1%D5%B6%D6%81" title="Ջերմային ցանց – Armenian" lang="hy" hreflang="hy" data-title="Ջերմային ցանց" data-language-autonym="Հայերեն" data-language-local-name="Armenian" class="interlanguage-link-target"><span>Հայերեն</span></a></li><li class="interlanguage-link interwiki-ja mw-list-item"><a href="https://ja.wikipedia.org/wiki/%E7%86%B1%E6%BA%90%E8%A8%AD%E5%82%99" title="熱源設備 – Japanese" lang="ja" hreflang="ja" data-title="熱源設備" 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-no mw-list-item"><a href="https://no.wikipedia.org/wiki/Vannb%C3%A5ren_varme" title="Vannbåren varme – Norwegian Bokmål" lang="nb" hreflang="nb" data-title="Vannbåren varme" data-language-autonym="Norsk bokmål" data-language-local-name="Norwegian Bokmål" class="interlanguage-link-target"><span>Norsk bokmål</span></a></li><li class="interlanguage-link interwiki-pl mw-list-item"><a href="https://pl.wikipedia.org/wiki/Sie%C4%87_ciep%C5%82ownicza" title="Sieć ciepłownicza – Polish" lang="pl" hreflang="pl" data-title="Sieć ciepłownicza" data-language-autonym="Polski" 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searchaux" style="display:none">Use of liquid or gaseous water in heating or cooling systems</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 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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 article <b>needs additional citations for <a href="/wiki/Wikipedia:Verifiability" title="Wikipedia:Verifiability">verification</a></b>.<span class="hide-when-compact"> Please help <a href="/wiki/Special:EditPage/Hydronics" title="Special:EditPage/Hydronics">improve this article</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 removed.<br /><small><span class="plainlinks"><i>Find sources:</i> <a rel="nofollow" class="external text" href="https://www.google.com/search?as_eq=wikipedia&q=%22Hydronics%22">"Hydronics"</a> – <a rel="nofollow" class="external text" href="https://www.google.com/search?tbm=nws&q=%22Hydronics%22+-wikipedia&tbs=ar:1">news</a> <b>·</b> <a rel="nofollow" class="external text" href="https://www.google.com/search?&q=%22Hydronics%22&tbs=bkt:s&tbm=bks">newspapers</a> <b>·</b> <a rel="nofollow" class="external text" href="https://www.google.com/search?tbs=bks:1&q=%22Hydronics%22+-wikipedia">books</a> <b>·</b> <a rel="nofollow" class="external text" href="https://scholar.google.com/scholar?q=%22Hydronics%22">scholar</a> <b>·</b> <a rel="nofollow" class="external text" href="https://www.jstor.org/action/doBasicSearch?Query=%22Hydronics%22&acc=on&wc=on">JSTOR</a></span></small></span> <span class="date-container"><i>(<span class="date">July 2022</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><b>Hydronics</b> (from <a href="/wiki/Ancient_Greek_language" class="mw-redirect" title="Ancient Greek language">Ancient Greek</a> <i> <a href="https://en.wiktionary.org/wiki/hydro" class="extiw" title="wikt:hydro">hydro-</a></i> 'water') is the use of <a href="/wiki/Liquid_water" class="mw-redirect" title="Liquid water">liquid water</a> or gaseous water (<a href="/wiki/Steam" title="Steam">steam</a>) or a water solution (usually <a href="/wiki/Glycol" class="mw-redirect" title="Glycol">glycol</a> with water) as a <a href="/wiki/Heat_transfer" title="Heat transfer">heat-transfer</a> medium in <a href="/wiki/Heating_system" title="Heating system">heating</a> and <a href="/wiki/Cooling" title="Cooling">cooling</a> systems.<sup id="cite_ref-:0_1-0" class="reference"><a href="#cite_note-:0-1"><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> The name differentiates such systems from <a href="/wiki/Oil_cooling" title="Oil cooling">oil</a> and <a href="/wiki/Refrigerant" title="Refrigerant">refrigerant</a> systems. </p><p>Historically, in large-scale commercial buildings such as <a href="/wiki/High-rise" class="mw-redirect" title="High-rise">high-rise</a> and <a href="/wiki/Campus" title="Campus">campus</a> facilities, a hydronic system may include both a chilled and a heated water loop, to provide for both heating and <a href="/wiki/Air_conditioning" title="Air conditioning">air conditioning</a>. <a href="/wiki/Chiller" title="Chiller">Chillers</a> and <a href="/wiki/Cooling_tower" title="Cooling tower">cooling towers</a> are used either separately or together as means to provide water cooling, while <a href="/wiki/Boiler" title="Boiler">boilers</a> heat water. A recent innovation is the <a href="/wiki/Chiller_boiler_system" title="Chiller boiler system">chiller boiler system</a>, which provides an efficient form of <a href="/wiki/HVAC" class="mw-redirect" title="HVAC">HVAC</a> for homes and smaller commercial spaces. </p> <figure class="mw-default-size mw-halign-right" typeof="mw:File/Thumb"><a href="/wiki/File:Hydronic_Unit_Heater.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/d/d3/Hydronic_Unit_Heater.jpg/220px-Hydronic_Unit_Heater.jpg" decoding="async" width="220" height="147" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/d/d3/Hydronic_Unit_Heater.jpg/330px-Hydronic_Unit_Heater.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/d/d3/Hydronic_Unit_Heater.jpg/440px-Hydronic_Unit_Heater.jpg 2x" data-file-width="6000" data-file-height="4000" /></a><figcaption>A hydronic fan unit heater used for maintaining warmth within an industrial setting. The fan draws cool, ambient air through the heat exchanger around the perimeter of the housing with pipes carrying hot glycol, and expels it out the centre.</figcaption></figure> <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="District_heating">District heating</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Hydronics&action=edit&section=1" title="Edit section: District heating"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1236090951">.mw-parser-output .hatnote{font-style:italic}.mw-parser-output div.hatnote{padding-left:1.6em;margin-bottom:0.5em}.mw-parser-output .hatnote i{font-style:normal}.mw-parser-output .hatnote+link+.hatnote{margin-top:-0.5em}@media print{body.ns-0 .mw-parser-output .hatnote{display:none!important}}</style><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/District_heating" title="District heating">District heating</a></div> <p>Many larger cities have a district heating system that provides, through underground piping, publicly available high temperature hot water and chilled water. A building in the service district may be connected to these on payment of a service fee. </p> <div class="mw-heading mw-heading2"><h2 id="Types_of_hydronic_system">Types of hydronic system</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Hydronics&action=edit&section=2" title="Edit section: Types of hydronic system"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="mw-heading mw-heading3"><h3 id="Basic_types">Basic types</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Hydronics&action=edit&section=3" title="Edit section: Basic types"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Hydronic systems can include the following kinds of distributions:<sup id="cite_ref-:0_1-1" class="reference"><a href="#cite_note-:0-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> </p> <ul><li>Chilled water systems</li> <li>Hot water systems</li> <li>Steam systems</li> <li>Steam condensate systems</li> <li>Ground source heat pump systems</li></ul> <div class="mw-heading mw-heading3"><h3 id="Classification">Classification</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Hydronics&action=edit&section=4" title="Edit section: Classification"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Hydronic systems are further classified in five ways: </p> <ul><li>Flow generation (forced flow or gravity flow)</li> <li>Temperature (low, medium, and high)</li> <li>Pressurization (low, medium, and high)</li> <li>Piping arrangement</li> <li>Pumping arrangement</li></ul> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Train_snow_melting,_hydronic.jpeg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/2/24/Train_snow_melting%2C_hydronic.jpeg/170px-Train_snow_melting%2C_hydronic.jpeg" decoding="async" width="170" height="227" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/2/24/Train_snow_melting%2C_hydronic.jpeg/255px-Train_snow_melting%2C_hydronic.jpeg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/2/24/Train_snow_melting%2C_hydronic.jpeg/340px-Train_snow_melting%2C_hydronic.jpeg 2x" data-file-width="1536" data-file-height="2048" /></a><figcaption>Snow melting hydronics</figcaption></figure> <div class="mw-heading mw-heading3"><h3 id="Piping_arrangements">Piping arrangements</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Hydronics&action=edit&section=5" title="Edit section: Piping arrangements"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Hydronic systems may be divided into several general piping arrangement categories: </p> <ul><li>Single or one-pipe</li> <li>Two pipe steam (direct return or reverse return)</li> <li>Three pipe</li> <li>Four pipe</li> <li>Series loop</li></ul> <div class="mw-heading mw-heading2"><h2 id="Single-pipe_steam">Single-pipe steam</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Hydronics&action=edit&section=6" title="Edit section: Single-pipe steam"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:2006_400x700_one_pipe_steam_radiator.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/f/f1/2006_400x700_one_pipe_steam_radiator.jpg/170px-2006_400x700_one_pipe_steam_radiator.jpg" decoding="async" width="170" height="298" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/f/f1/2006_400x700_one_pipe_steam_radiator.jpg/255px-2006_400x700_one_pipe_steam_radiator.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/f/f1/2006_400x700_one_pipe_steam_radiator.jpg/340px-2006_400x700_one_pipe_steam_radiator.jpg 2x" data-file-width="400" data-file-height="700" /></a><figcaption>Single-pipe steam radiator</figcaption></figure> <p>In the oldest modern hydronic heating technology, a single-pipe steam system delivers steam to the <a href="/wiki/Radiator" title="Radiator">radiators</a> where the steam gives up its heat and is <a href="/wiki/Condensation" title="Condensation">condensed</a> back to water. The radiators and steam supply pipes are pitched so that <a href="/wiki/Gravity" title="Gravity">gravity</a> eventually takes this condensate back down through the steam supply piping to the boiler where it can once again be turned into steam and returned to the radiators. </p><p>Despite its name, a radiator does not primarily heat a room by radiation. If positioned correctly a radiator will create an air convection current in the room, which will provide the main heat transfer mechanism. It is generally agreed that for the best results a steam radiator should be no more than one to two inches (2.5 to 5cm) from a wall. </p><p>Single-pipe systems are limited in both their ability to deliver high volumes of steam (that is, heat)<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (January 2014)">citation needed</span></a></i>]</sup> and the ability to control the flow of steam to individual radiators<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (January 2014)">citation needed</span></a></i>]</sup> (because closing off the steam supply traps condensate in the radiators). Because of these limitations, single-pipe systems are no longer preferred. </p><p>These systems depend on the proper operation of thermostatic air-venting valves located on radiators throughout the heated area. When the system is not in use, these valves are open to the atmosphere, and radiators and pipes contain air. When a heating cycle begins, the boiler produces steam, which expands and displaces the air in the system. The air exits the system through the air-venting valves on the radiators and on the steam pipes themselves. The thermostatic valves close when they become hot; in the most common kind, the vapor pressure of a small amount of alcohol in the valve exerts the force to actuate the valve and prevent steam from leaving the radiator. When the valve cools, air enters the system to replace the condensing steam. </p><p>Some more modern valves can be adjusted to allow for more rapid or slower venting. In general, valves nearest to the boiler should vent the slowest, and valves furthest from the boiler should vent the fastest.<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (January 2014)">citation needed</span></a></i>]</sup> Ideally, steam should reach each valve and close each and every valve at the same time, so that the system can work at maximal efficiency; this condition is known as a "balanced" system.<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (February 2016)">citation needed</span></a></i>]</sup> </p> <div class="mw-heading mw-heading2"><h2 id="Two-pipe_steam_systems">Two-pipe steam systems</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Hydronics&action=edit&section=7" title="Edit section: Two-pipe steam systems"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>In two-pipe steam systems, there is a return path for the condensate and it may involve <a href="/wiki/Condensate_pump" title="Condensate pump">pumps</a> as well as gravity-induced flow. The flow of steam to individual radiators can be modulated using manual or automatic <a href="/wiki/Valve" title="Valve">valves</a>. </p> <div class="mw-heading mw-heading2"><h2 id="Two-pipe_direct_return_system">Two-pipe direct return system</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Hydronics&action=edit&section=8" title="Edit section: Two-pipe direct return system"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The return piping, as the name suggests, takes the most direct path back to the boiler. </p> <div class="mw-heading mw-heading3"><h3 id="Advantages">Advantages</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Hydronics&action=edit&section=9" title="Edit section: Advantages"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Lower cost of return piping in most (but not all) applications, and the supply and return piping are separated. </p> <div class="mw-heading mw-heading3"><h3 id="Disadvantages">Disadvantages</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Hydronics&action=edit&section=10" title="Edit section: Disadvantages"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>This system can be difficult to balance due to the supply line being a different length than the return; the further the heat transfer device is from the boiler, the more pronounced the pressure difference. Because of this, it is always recommended to: minimize the distribution piping pressure drops; use a pump with a <span class="define-content" style="padding-left:0.1em; padding-right:0.1em; color:var(--color-subtle, #54595d); border:1px solid var(--border-color-subtle, #c8ccd1);">flat head characteristic</span><sup class="noprint Inline-Template Template-Define" style="margin-left:0.1em; white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Manual_of_Style" title="Wikipedia:Manual of Style"><span title="flat head characteristic (January 2016)">when defined as?</span></a></i>]</sup>, include balancing and flow-measuring devices at each terminal or branch circuit; and use control valves with a <span class="define-content" style="padding-left:0.1em; padding-right:0.1em; color:var(--color-subtle, #54595d); border:1px solid var(--border-color-subtle, #c8ccd1);">high head loss</span><sup class="noprint Inline-Template Template-Define" style="margin-left:0.1em; white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Manual_of_Style" title="Wikipedia:Manual of Style"><span title="high head loss (January 2016)">when defined as?</span></a></i>]</sup> at the terminals. </p> <div class="mw-heading mw-heading2"><h2 id="Two-pipe_reverse_return_system">Two-pipe reverse return system</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Hydronics&action=edit&section=11" title="Edit section: Two-pipe reverse return system"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The two-pipe reverse return configuration which is sometimes called 'the three-pipe system' is different from the two-pipe system in the way that water returns to the boiler. In a two-pipe system, once the water has left the first radiator, it returns to the boiler to be reheated, and so with the second and third etc. With the two-pipe reverse return, the return pipe travels to the last radiator in the system before returning to the boiler to be reheated. </p> <div class="mw-heading mw-heading3"><h3 id="Advantages_2">Advantages</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Hydronics&action=edit&section=12" title="Edit section: Advantages"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The advantage with the two-pipe reverse return system is that the pipe run to each radiator is about the same, this ensures that the frictional resistance to the flow of water in each radiator is the same. This allows easy balancing of the system. </p> <div class="mw-heading mw-heading3"><h3 id="Disadvantages_2">Disadvantages</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Hydronics&action=edit&section=13" title="Edit section: Disadvantages"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The installer or repair person cannot trust that every system is self-balancing without properly testing it. </p> <div class="mw-heading mw-heading2"><h2 id="Water_loops">Water loops</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Hydronics&action=edit&section=14" title="Edit section: Water loops"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Modern systems almost always use heated water rather than steam. This opens the system to the possibility of also using chilled water to provide <a href="/wiki/Air_conditioning" title="Air conditioning">air conditioning</a>. </p><p>In homes, the water loop may be as simple as a single pipe that "loops" the flow through every radiator in a zone. In such a system, flow to the individual radiators cannot be modulated as all of the water is flowing through every radiator in the zone. Slightly more complicated systems use a "main" pipe that flows uninterrupted around the zone; the individual radiators tap off a small portion of the flow in the main pipe. In these systems, individual radiators can be modulated. Alternatively, a number of loops with several radiators can be installed, the flow in each loop or zone controlled by a <a href="/wiki/Zone_valve" title="Zone valve">zone valve</a> connected to a <a href="/wiki/Thermostat" title="Thermostat">thermostat</a>. </p><p>In most water systems, the water is circulated by means of one or more <a href="/wiki/Circulator_pump" title="Circulator pump">circulator pumps</a>. This is in marked contrast to steam systems where the inherent pressure of the steam is sufficient to distribute the steam to remote points in the system. A system may be broken up into individual heating <i>zones</i> using either multiple circulator pumps or a single pump and electrically operated <a href="/wiki/Zone_valve" title="Zone valve">zone valves</a>. </p> <div class="mw-heading mw-heading2"><h2 id="Improved_efficiency_and_operating_costs">Improved efficiency and operating costs</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Hydronics&action=edit&section=15" title="Edit section: Improved efficiency and operating costs"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>There have been considerable improvements in the efficiency and therefore the operating costs of a hydronic heating system with the introduction of insulating products. </p><p>Radiator Panel system pipes are covered with a fire rated, flexible and lightweight elastomeric rubber material designed for thermal insulation. Slab Heating efficiency is improved with the installation of a thermal barrier made of foam. There are now many product offerings on the market with different energy ratings and installation methods. </p> <div class="mw-heading mw-heading2"><h2 id="Balancing">Balancing</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Hydronics&action=edit&section=16" title="Edit section: Balancing"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Most hydronic systems require <a href="/wiki/Hydronic_Balancing" class="mw-redirect" title="Hydronic Balancing">balancing</a>. This involves measuring and setting the flow to achieve an optimal distribution of energy in the system. In a balanced system every radiator gets just enough hot water to allow it to heat up fully. </p> <div class="mw-heading mw-heading2"><h2 id="Boiler_water_treatment">Boiler water treatment</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Hydronics&action=edit&section=17" title="Edit section: Boiler water treatment"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Residential systems may use ordinary tap water, but sophisticated commercial systems often add various chemicals to the system water. For example, these added chemicals may: </p> <ul><li>Inhibit <a href="/wiki/Corrosion" title="Corrosion">corrosion</a></li> <li><a href="/wiki/Antifreeze" title="Antifreeze">Prevent freezing</a> of the water in the system</li> <li>Increase the boiling point of the water in the system</li> <li>Inhibit the growth of <a href="/wiki/Mold_(fungus)" class="mw-redirect" title="Mold (fungus)">mold</a> and <a href="/wiki/Bacteria" title="Bacteria">bacteria</a></li> <li>Allow improved leak detection (for example, <a href="/wiki/Dye" title="Dye">dyes</a> that <a href="/wiki/Fluorescence" title="Fluorescence">fluoresce</a> under <a href="/wiki/Ultraviolet_light" class="mw-redirect" title="Ultraviolet light">ultraviolet light</a>)</li></ul> <div class="mw-heading mw-heading2"><h2 id="Air_elimination">Air elimination</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Hydronics&action=edit&section=18" title="Edit section: Air elimination"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>All hydronic systems must have a means to eliminate air from the system. A properly designed, air-free system should continue to function normally for many years. </p><p>Air causes irritating system noises, and interrupts proper heat transfer to and from the circulating fluids. In addition, unless reduced below an acceptable level, the <a href="/wiki/Oxygen" title="Oxygen">oxygen</a> dissolved in water causes <a href="/wiki/Corrosion" title="Corrosion">corrosion</a>. This corrosion can cause rust and scale to build up on the piping. Over time these particles can become loose and travel around the pipes, reducing or even blocking the flow as well as damaging pump seals and other components. </p> <div class="mw-heading mw-heading3"><h3 id="Water-loop_system">Water-loop system</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Hydronics&action=edit&section=19" title="Edit section: Water-loop system"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Water-loop systems can also experience air problems. Air found within hydronic water-loop systems may be classified into three forms: </p> <div class="mw-heading mw-heading4"><h4 id="Free_air">Free air</h4><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Hydronics&action=edit&section=20" title="Edit section: Free air"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Various devices such as manual and automatic air vents are used to address free air which floats up to the high points throughout the system. Automatic air vents contain a valve that is operated by a float. When air is present, the float drops, allowing the valve to open and bleed air out. When water reaches (fills) the valve, the float lifts, blocking the water from escaping. Small (domestic) versions of these valves in older systems are sometimes fitted with a <a href="/wiki/Schrader_valve" title="Schrader valve">Schrader-type air valve fitting</a>, and any trapped, now-compressed air can be bled from the valve by manually depressing the valve stem until water rather than air begins to emerge. </p> <div class="mw-heading mw-heading4"><h4 id="Entrained_air">Entrained air</h4><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Hydronics&action=edit&section=21" title="Edit section: Entrained air"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Entrained air is air bubbles that travel around in the piping at the same velocity as the water. Air "scoops" are one example of products which attempt to remove this type of air. </p> <div class="mw-heading mw-heading4"><h4 id="Dissolved_air">Dissolved air</h4><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Hydronics&action=edit&section=22" title="Edit section: Dissolved air"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Dissolved air is also present in the system water and the amount is determined principally by the temperature and pressure (see <a href="/wiki/Henry%27s_Law" class="mw-redirect" title="Henry's Law">Henry's Law</a>) of the incoming water. On average, tap water contains between 8-10% dissolved air by volume. </p><p>Removal of dissolved, free and entrained air can only be achieved with a high-efficiency air elimination device that includes a coalescing medium that continually scrubs the air out of the system. Tangential or centrifugal style air separator devices are limited to removal of free and entrained air only. </p> <div class="mw-heading mw-heading2"><h2 id="Accommodating_thermal_expansion">Accommodating thermal expansion</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Hydronics&action=edit&section=23" title="Edit section: Accommodating thermal expansion"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Water expands as it heats and contracts as it cools. A water-loop hydronic system must have one or more <a href="/wiki/Expansion_tank" title="Expansion tank">expansion tanks</a> in the system to accommodate this varying volume of the working fluid. These tanks often use a rubber diaphragm pressurised with <a href="/wiki/Compressed_air" title="Compressed air">compressed air</a>. The expansion tank accommodates the expanded water by further air compression and helps maintain a roughly constant pressure in the system across the expected change in fluid volume. Simple <a href="/wiki/Cistern" title="Cistern">cisterns</a> open to atmospheric pressure are also used. </p><p><br /> Water also expands drastically as it vaporizes, or flashes, into steam. Sparge pipes can help accommodate flashing that may occur as high pressure condensate enters a lower pressure region.<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="Automatic_fill_mechanisms">Automatic fill mechanisms</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Hydronics&action=edit&section=24" title="Edit section: Automatic fill mechanisms"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Hydronic systems are usually connected to a water supply (such as the public water supply). An automatic valve regulates the amount of water in the system and also prevents <a href="/wiki/Backflow_prevention_device" title="Backflow prevention device">backflow</a> of system water (and any water treatment chemicals) into the water supply. </p> <div class="mw-heading mw-heading2"><h2 id="Safety_mechanisms">Safety mechanisms</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Hydronics&action=edit&section=25" title="Edit section: Safety mechanisms"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Excessive heat or pressure may cause the system to fail. At least one combination over-temperature and over-pressure <a href="/wiki/Relief_valve" title="Relief valve">relief valve</a> is always fitted to the system to allow the steam or water to vent to the atmosphere in case of the failure of some mechanism (such as the boiler temperature control) rather than allowing the catastrophic bursting of the piping, radiators, or boiler. The relief valve usually has a manual operating handle to allow testing and the flushing of contaminants (such as grit) that may cause the valve to leak under otherwise-normal operating conditions. </p><p><br /> Rapid condensation of steam can also lead to <a href="/wiki/Water_hammer" title="Water hammer">water hammer</a>, which during rapid volume change from gas to liquid leads to a powerful vacuum force. This can damage and destroy fittings, valves and equipment. Proper design and the addition of vacuum breakers reduce or eliminate the risk of these problems.<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-heading2"><h2 id="Typical_schematic_with_control_devices_shown">Typical schematic with control devices shown</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Hydronics&action=edit&section=26" title="Edit section: Typical schematic with control devices shown"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Four_Pipe_Systems.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/1/1b/Four_Pipe_Systems.jpg" decoding="async" width="480" height="346" class="mw-file-element" data-file-width="480" data-file-height="346" /></a><figcaption>Symbols</figcaption></figure> <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=Hydronics&action=edit&section=27" title="Edit section: See also"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a href="/wiki/Aquastat" title="Aquastat">Aquastat</a></li> <li><a href="/wiki/Central_heating" title="Central heating">Central heating</a></li> <li><a href="/wiki/Hydronic_balancing" title="Hydronic balancing">Hydronic balancing</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/Uniform_Mechanical_Code" title="Uniform Mechanical Code">Uniform Mechanical Code</a></li></ul> <div style="clear:both;" class=""></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=Hydronics&action=edit&section=28" 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"><ol class="references"> <li id="cite_note-:0-1"><span class="mw-cite-backlink">^ <a href="#cite_ref-:0_1-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-:0_1-1"><sup><i><b>b</b></i></sup></a></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 class="citation web cs1"><a rel="nofollow" class="external text" href="https://epubs.iapmo.org/2021/UMC/#p=10">"2021 Uniform Mechanical Code"</a>. <i>epubs.iapmo.org</i> (Code book). IAPMO. 2021. pp. ix, 16<span class="reference-accessdate">. Retrieved <span class="nowrap">2022-07-22</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=epubs.iapmo.org&rft.atitle=2021+Uniform+Mechanical+Code&rft.pages=ix%2C+16&rft.date=2021&rft_id=https%3A%2F%2Fepubs.iapmo.org%2F2021%2FUMC%2F%23p%3D10&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHydronics" class="Z3988"></span></span> </li> <li id="cite_note-2"><span class="mw-cite-backlink"><b><a href="#cite_ref-2">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSiegenthaler2012" class="citation book cs1">Siegenthaler, John (2012). <i>Modern Hydronic Heating</i> (Third ed.). Cengage Learning. p. 3.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Modern+Hydronic+Heating&rft.pages=3&rft.edition=Third&rft.pub=Cengage+Learning&rft.date=2012&rft.aulast=Siegenthaler&rft.aufirst=John&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHydronics" class="Z3988"></span></span> </li> <li id="cite_note-3"><span class="mw-cite-backlink"><b><a href="#cite_ref-3">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFHall2017" class="citation web cs1">Hall, Norm (2017-05-15). <a rel="nofollow" class="external text" href="https://www.deppmann.com/blog/monday-morning-minutes/medium-and-high-pressure-steam-vented-flash-tank-trim/">"Medium and High Pressure Steam Vented Flash Tank Trim"</a>. <i>RL Deppmann</i><span class="reference-accessdate">. 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Retrieved <span class="nowrap">2022-07-22</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Plant+Engineering&rft.atitle=Plant+Engineering+%7C+Water+hammer+in+steam+systems%3A+cause+and+effect&rft.date=2006-09-01&rft.aulast=Harms&rft.aufirst=Bill&rft_id=https%3A%2F%2Fwww.plantengineering.com%2Farticles%2Fwater-hammer-in-steam-systems-cause-and-effect%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHydronics" class="Z3988"></span></span> </li> </ol></div></div> <div class="navbox-styles"><style data-mw-deduplicate="TemplateStyles:r1129693374">.mw-parser-output .hlist dl,.mw-parser-output .hlist ol,.mw-parser-output .hlist ul{margin:0;padding:0}.mw-parser-output .hlist dd,.mw-parser-output .hlist dt,.mw-parser-output .hlist li{margin:0;display:inline}.mw-parser-output .hlist.inline,.mw-parser-output .hlist.inline dl,.mw-parser-output .hlist.inline ol,.mw-parser-output .hlist.inline ul,.mw-parser-output .hlist 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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 href="/wiki/Psychrometrics" title="Psychrometrics">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 class="mw-selflink selflink">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 href="/wiki/Psychrometrics" title="Psychrometrics">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> 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