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refrigerant flow heat pump</title> <meta name="description" content="Search results for: variable refrigerant flow heat pump"> <meta name="keywords" content="variable refrigerant flow heat pump"> <meta name="viewport" content="width=device-width, initial-scale=1, minimum-scale=1, maximum-scale=1, user-scalable=no"> <meta charset="utf-8"> <link href="https://cdn.waset.org/favicon.ico" type="image/x-icon" rel="shortcut icon"> <link href="https://cdn.waset.org/static/plugins/bootstrap-4.2.1/css/bootstrap.min.css" rel="stylesheet"> <link href="https://cdn.waset.org/static/plugins/fontawesome/css/all.min.css" rel="stylesheet"> <link href="https://cdn.waset.org/static/css/site.css?v=150220211555" rel="stylesheet"> </head> <body> <header> <div class="container"> <nav class="navbar navbar-expand-lg navbar-light"> <a class="navbar-brand" href="https://waset.org"> <img src="https://cdn.waset.org/static/images/wasetc.png" alt="Open Science Research Excellence" title="Open Science Research 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method="get" action="https://publications.waset.org/abstracts/search"> <div id="custom-search-input"> <div class="input-group"> <i class="fas fa-search"></i> <input type="text" class="search-query" name="q" placeholder="Author, Title, Abstract, Keywords" value="variable refrigerant flow heat pump"> <input type="submit" class="btn_search" value="Search"> </div> </div> </form> </div> </div> <div class="row mt-3"> <div class="col-sm-3"> <div class="card"> <div class="card-body"><strong>Commenced</strong> in January 2007</div> </div> </div> <div class="col-sm-3"> <div class="card"> <div class="card-body"><strong>Frequency:</strong> Monthly</div> </div> </div> <div class="col-sm-3"> <div class="card"> <div class="card-body"><strong>Edition:</strong> International</div> </div> </div> <div class="col-sm-3"> <div class="card"> <div class="card-body"><strong>Paper Count:</strong> 9186</div> </div> </div> </div> <h1 class="mt-3 mb-3 text-center" style="font-size:1.6rem;">Search results for: variable refrigerant flow heat pump</h1> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">9186</span> A Study on Changing of Energy-Saving Performance of GHP Air Conditioning System with Time-Series Variation</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Ying%20Xin">Ying Xin</a>, <a href="https://publications.waset.org/abstracts/search?q=Shigeki%20Kametani"> Shigeki Kametani</a> </p> <p class="card-text"><strong>Abstract:</strong></p> This paper deals the energy saving performance of GHP (Gas engine heat pump) air conditioning system has improved with time-series variation. There are two types of air conditioning systems, VRF (Variable refrigerant flow) and central cooling and heating system. VRF is classified as EHP (Electric driven heat pump) and GHP. EHP drives the compressor with electric motor. GHP drives the compressor with the gas engine. The electric consumption of GHP is less than one tenth of EHP does. In this study, the energy consumption data of GHP installed the junior high schools was collected. An annual and monthly energy consumption per rated thermal output power of each apparatus was calculated, and then their energy efficiency was analyzed. From these data, we investigated improvement of the energy saving of the GHP air conditioning system by the change in the generation. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=energy-saving" title="energy-saving">energy-saving</a>, <a href="https://publications.waset.org/abstracts/search?q=variable%20refrigerant%20flow" title=" variable refrigerant flow"> variable refrigerant flow</a>, <a href="https://publications.waset.org/abstracts/search?q=gas%20engine%20heat%20pump" title=" gas engine heat pump"> gas engine heat pump</a>, <a href="https://publications.waset.org/abstracts/search?q=electric%20driven%20heat%20pump" title=" electric driven heat pump"> electric driven heat pump</a>, <a href="https://publications.waset.org/abstracts/search?q=air%20conditioning%20system" title=" air conditioning system"> air conditioning system</a> </p> <a href="https://publications.waset.org/abstracts/2488/a-study-on-changing-of-energy-saving-performance-of-ghp-air-conditioning-system-with-time-series-variation" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/2488.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">298</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">9185</span> Numerical Investigation of Flow and Heat Transfer Characteristics of a Natural Refrigerant within a Vortex Tube</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Mirza%20Popovac">Mirza Popovac</a> </p> <p class="card-text"><strong>Abstract:</strong></p> This paper investigates the application of the vortex tubes towards increasing the efficiency of high temperature heat pumps based on natural refrigerants, by recovering a part of the expansion work within the refrigerant cycle. To this purpose the 3D Navier-Stokes solver is used to perform a set of numerical simulations, investigating the vortex tube performance. Firstly, the fluid flow and heat transfer characteristics are analyzed for standard configurations of vortex tubes, and the obtained results are validated against the experimental and numerical data available in literature. Subsequently, different geometry specifications are analyzed, as well as the interplay between relevant heat pump operating conditions and the properties of natural refrigerants. Finally, the characteristic curve of performance will be derived for investigated vortex tubes specifications when used within high temperature heat pumps. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=heat%20pump" title="heat pump">heat pump</a>, <a href="https://publications.waset.org/abstracts/search?q=vortex%20tube" title=" vortex tube"> vortex tube</a>, <a href="https://publications.waset.org/abstracts/search?q=CFD" title=" CFD"> CFD</a>, <a href="https://publications.waset.org/abstracts/search?q=natural%20refrigerant" title=" natural refrigerant"> natural refrigerant</a> </p> <a href="https://publications.waset.org/abstracts/105555/numerical-investigation-of-flow-and-heat-transfer-characteristics-of-a-natural-refrigerant-within-a-vortex-tube" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/105555.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">141</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">9184</span> Post Occupancy Evaluation of the Green Office Building with Different Air-Conditioning Systems</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Ziwei%20Huang">Ziwei Huang</a>, <a href="https://publications.waset.org/abstracts/search?q=Jian%20Ge"> Jian Ge</a>, <a href="https://publications.waset.org/abstracts/search?q=Jie%20Shen"> Jie Shen</a>, <a href="https://publications.waset.org/abstracts/search?q=Jiantao%20Weng"> Jiantao Weng</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Retrofitting of existing buildings plays a critical role to achieve sustainable development. This is being considered as one of the approaches to achieving sustainability in the built environment. In order to evaluate the different air-conditioning systems effectiveness and user satisfaction of the existing building which had transformed into green building effectively and accurately. This article takes the green office building in Zhejiang province, China as an example, analyzing the energy consumption, occupant satisfaction and indoor environment quality (IEQ) from the perspective of the thermal environment. This building is special because it combines ground source heat pump system and Variable Refrigerant Flow (VRF) air-conditioning system. Results showed that the ground source heat pump system(EUIa≈25.6) consumes more energy than VRF(EUIb≈23.8). In terms of a satisfaction survey, the use of the VRF air-conditioning was more satisfactory in temperature. However, the ground source heat pump is more satisfied in air quality. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=post-occupancy%20evaluation" title="post-occupancy evaluation">post-occupancy evaluation</a>, <a href="https://publications.waset.org/abstracts/search?q=green%20office%20building" title=" green office building"> green office building</a>, <a href="https://publications.waset.org/abstracts/search?q=air-conditioning%20systems" title=" air-conditioning systems"> air-conditioning systems</a>, <a href="https://publications.waset.org/abstracts/search?q=ground%20source%20heat%20pump%20system" title=" ground source heat pump system"> ground source heat pump system</a> </p> <a href="https://publications.waset.org/abstracts/88345/post-occupancy-evaluation-of-the-green-office-building-with-different-air-conditioning-systems" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/88345.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">196</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">9183</span> Experimental Analysis of the Influence of Water Mass Flow Rate on the Performance of a CO2 Direct-Expansion Solar Assisted Heat Pump </h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Sabrina%20N.%20Rabelo">Sabrina N. Rabelo</a>, <a href="https://publications.waset.org/abstracts/search?q=Tiago%20de%20F.%20Paulino"> Tiago de F. Paulino</a>, <a href="https://publications.waset.org/abstracts/search?q=Willian%20M.%20Duarte"> Willian M. Duarte</a>, <a href="https://publications.waset.org/abstracts/search?q=Samer%20Sawalha"> Samer Sawalha</a>, <a href="https://publications.waset.org/abstracts/search?q=Luiz%20Machado"> Luiz Machado</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Energy use is one of the main indicators for the economic and social development of a country, reflecting directly in the quality of life of the population. The expansion of energy use together with the depletion of fossil resources and the poor efficiency of energy systems have led many countries in recent years to invest in renewable energy sources. In this context, solar-assisted heat pump has become very important in energy industry, since it can transfer heat energy from the sun to water or another absorbing source. The direct-expansion solar assisted heat pump (DX-SAHP) water heater system operates by receiving solar energy incident in a solar collector, which serves as an evaporator in a refrigeration cycle, and the energy reject by the condenser is used for water heating. In this paper, a DX-SAHP using carbon dioxide as refrigerant (R744) was assembled, and the influence of the variation of the water mass flow rate in the system was analyzed. The parameters such as high pressure, water outlet temperature, gas cooler outlet temperature, evaporator temperature, and the coefficient of performance were studied. The mainly components used to assemble the heat pump were a reciprocating compressor, a gas cooler which is a countercurrent concentric tube heat exchanger, a needle-valve, and an evaporator that is a copper bare flat plate solar collector designed to capture direct and diffuse radiation. Routines were developed in the LabVIEW and CoolProp through MATLAB software’s, respectively, to collect data and calculate the thermodynamics properties. The range of coefficient of performance measured was from 3.2 to 5.34. It was noticed that, with the higher water mass flow rate, the water outlet temperature decreased, and consequently, the coefficient of performance of the system increases since the heat transfer in the gas cooler is higher. In addition, the high pressure of the system and the CO<sub>2</sub> gas cooler outlet temperature decreased. The heat pump using carbon dioxide as a refrigerant, especially operating with solar radiation has been proven to be a renewable source in an efficient system for heating residential water compared to electrical heaters reaching temperatures between 40 °C and 80 °C. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=water%20mass%20flow%20rate" title="water mass flow rate">water mass flow rate</a>, <a href="https://publications.waset.org/abstracts/search?q=R-744" title=" R-744"> R-744</a>, <a href="https://publications.waset.org/abstracts/search?q=heat%20pump" title=" heat pump"> heat pump</a>, <a href="https://publications.waset.org/abstracts/search?q=solar%20evaporator" title=" solar evaporator"> solar evaporator</a>, <a href="https://publications.waset.org/abstracts/search?q=water%20heater" title=" water heater"> water heater</a> </p> <a href="https://publications.waset.org/abstracts/87164/experimental-analysis-of-the-influence-of-water-mass-flow-rate-on-the-performance-of-a-co2-direct-expansion-solar-assisted-heat-pump" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/87164.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">176</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">9182</span> Evaluation of Low-Global Warming Potential Refrigerants in Vapor Compression Heat Pumps</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Hamed%20Jafargholi">Hamed Jafargholi</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Global warming presents an immense environmental risk, causing detrimental impacts on ecological systems and putting coastal areas at risk. Implementing efficient measures to minimize greenhouse gas emissions and the use of fossil fuels is essential to reducing global warming. Vapor compression heat pumps provide a practical method for harnessing energy from waste heat sources and reducing energy consumption. However, traditional working fluids used in these heat pumps generally contain a significant global warming potential (GWP), which might cause severe greenhouse effects if they are released. The goal of the emphasis on low-GWP (below 150) refrigerants is to further the vapor compression heat pumps. A classification system for vapor compression heat pumps is offered, with different boundaries based on the needed heat temperature and advancements in heat pump technology. A heat pump could be classified as a low temperature heat pump (LTHP), medium temperature heat pump (MTHP), high temperature heat pump (HTHP), or ultra-high temperature heat pump (UHTHP). The HTHP/UHTHP border is 160 °C, the MTHP/HTHP and LTHP/MTHP limits are 100 and 60 °C, respectively. The refrigerant is one of the most important parts of a vapor compression heat pump system. Presently, the main ways to choose a refrigerant are based on ozone depletion potential (ODP) and GWP, with GWP being the lowest possible value and ODP being zero. Pure low-GWP refrigerants, such as natural refrigerants (R718 and R744), hydrocarbons (R290, R600), hydrofluorocarbons (R152a and R161), hydrofluoroolefins (R1234yf, R1234ze(E)), and hydrochlorofluoroolefin (R1233zd(E)), were selected as candidates for vapor compression heat pump systems based on these selection principles. The performance, characteristics, and potential uses of these low-GWP refrigerants in heat pump systems are investigated in this paper. As vapor compression heat pumps with pure low-GWP refrigerants become more common, more and more low-grade heat can be recovered. This means that energy consumption would decrease. The research outputs showed that the refrigerants R718 for UHTHP application, R1233zd(E) for HTHP application, R600, R152a, R161, R1234ze(E) for MTHP, and R744, R290, and R1234yf for LTHP application are appropriate. The selection of an appropriate refrigerant should, in fact, take into consideration two different environmental and thermodynamic points of view. It might be argued that, depending on the situation, a trade-off between these two groups should constantly be considered. The environmental approach is now far stronger than it was previously, according to the European Union regulations. This will promote sustainable energy consumption and social development in addition to assisting in the reduction of greenhouse gas emissions and the management of global warming. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=vapor%20compression" title="vapor compression">vapor compression</a>, <a href="https://publications.waset.org/abstracts/search?q=global%20warming%20potential" title=" global warming potential"> global warming potential</a>, <a href="https://publications.waset.org/abstracts/search?q=heat%20pumps" title=" heat pumps"> heat pumps</a>, <a href="https://publications.waset.org/abstracts/search?q=greenhouse" title=" greenhouse"> greenhouse</a> </p> <a href="https://publications.waset.org/abstracts/189024/evaluation-of-low-global-warming-potential-refrigerants-in-vapor-compression-heat-pumps" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/189024.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">34</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">9181</span> Dynamic Modeling of Energy Systems Adapted to Low Energy Buildings in Lebanon</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Nadine%20Yehya">Nadine Yehya</a>, <a href="https://publications.waset.org/abstracts/search?q=Chantal%20Maatouk"> Chantal Maatouk</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Low energy buildings have been developed to achieve global climate commitments in reducing energy consumption. They comprise energy efficient buildings, zero energy buildings, positive buildings and passive house buildings. The reduced energy demands in Low Energy buildings call for advanced building energy modeling that focuses on studying active building systems such as heating, cooling and ventilation, improvement of systems performances, and development of control systems. Modeling and building simulation have expanded to cover different modeling approach i.e.: detailed physical model, dynamic empirical models, and hybrid approaches, which are adopted by various simulation tools. This paper uses DesignBuilder with EnergyPlus simulation engine in order to; First, study the impact of efficiency measures on building energy behavior by comparing Low energy residential model to a conventional one in Beirut-Lebanon. Second, choose the appropriate energy systems for the studied case characterized by an important cooling demand. Third, study dynamic modeling of Variable Refrigerant Flow (VRF) system in EnergyPlus that is chosen due to its advantages over other systems and its availability in the Lebanese market. Finally, simulation of different energy systems models with different modeling approaches is necessary to confront the different modeling approaches and to investigate the interaction between energy systems and building envelope that affects the total energy consumption of Low Energy buildings. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=physical%20model" title="physical model">physical model</a>, <a href="https://publications.waset.org/abstracts/search?q=variable%20refrigerant%20flow%20heat%20pump" title=" variable refrigerant flow heat pump"> variable refrigerant flow heat pump</a>, <a href="https://publications.waset.org/abstracts/search?q=dynamic%20modeling" title=" dynamic modeling"> dynamic modeling</a>, <a href="https://publications.waset.org/abstracts/search?q=EnergyPlus" title=" EnergyPlus"> EnergyPlus</a>, <a href="https://publications.waset.org/abstracts/search?q=the%20modeling%20approach" title=" the modeling approach"> the modeling approach</a> </p> <a href="https://publications.waset.org/abstracts/97232/dynamic-modeling-of-energy-systems-adapted-to-low-energy-buildings-in-lebanon" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/97232.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">221</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">9180</span> Making Heat Pumps More Compatible with Environmental and Climatic Conditions</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Erol%20Sahin">Erol Sahin</a>, <a href="https://publications.waset.org/abstracts/search?q=Nesrin%20Adiguzel"> Nesrin Adiguzel</a> </p> <p class="card-text"><strong>Abstract:</strong></p> In this study, the effects of air temperature and relative humidity on the operation of the heat pump were examined experimentally. The results were analyzed in an energy and exergetic way. Two heat pumps were used in the experimental system established for experimental analysis. With the first heat pump, the relative humidity and temperature of atmospheric air are reduced. The air at low humidity and temperature is given heat and water vapor to the desired extent on the channel that reaches the other heat pump. Effects of the air reaching the desired humidity and temperature in the 2nd heat pump; temperature, humidity, pressure, flow, and current are detected by meters. The measured values and the exergy yield and thermodynamic favor ratios of the system and its components were determined. In this way, the effects of temperature and relative humidity change in the heat pump and components were tried to be revealed. Relative humidity in the air caused a significant increase in the loss of exergy in the evaporator. This has shown that cooling machines experience greater exergy in areas with high relative humidity. The highest COPSM values were determined to be at 30% and 40%, which is the least relative humidity values. The results showed that heat pump exergy efficiency was affected by increased temperature and relative humidity. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=relative%20humidity" title="relative humidity">relative humidity</a>, <a href="https://publications.waset.org/abstracts/search?q=effects%20of%20relative%20humidity%20on%20heat%20pumps" title=" effects of relative humidity on heat pumps"> effects of relative humidity on heat pumps</a>, <a href="https://publications.waset.org/abstracts/search?q=exergy%20analysis" title=" exergy analysis"> exergy analysis</a>, <a href="https://publications.waset.org/abstracts/search?q=exergy%20analysis%20in%20heat%20pumps" title=" exergy analysis in heat pumps"> exergy analysis in heat pumps</a>, <a href="https://publications.waset.org/abstracts/search?q=exergy%20efficiency" title=" exergy efficiency"> exergy efficiency</a> </p> <a href="https://publications.waset.org/abstracts/164432/making-heat-pumps-more-compatible-with-environmental-and-climatic-conditions" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/164432.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">128</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">9179</span> Experimental Investigation of Gas Bubble Behaviours in a Domestic Heat Pump Water Heating System</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=J.%20B.%20Qin">J. B. Qin</a>, <a href="https://publications.waset.org/abstracts/search?q=X.%20H.%20Jiang"> X. H. Jiang</a>, <a href="https://publications.waset.org/abstracts/search?q=Y.%20T.%20Ge"> Y. T. Ge</a> </p> <p class="card-text"><strong>Abstract:</strong></p> The growing awareness of global warming potential has internationally aroused interest and demand in reducing greenhouse gas emissions produced by human activity. Much national energy in the UK had been consumed in the residential sector mainly for space heating and domestic hot water production. Currently, gas boilers are mostly applied in the domestic water heating which contribute significantly to excessive CO<sub>2</sub> emissions and consumption of primary energy resources. The issues can be solved by popularizing heat pump systems that are attributable to higher performance efficiency than those of traditional gas boilers. Even so, the heat pump system performance can be further enhanced if the dissolved gases in its hot water circuit can be efficiently discharged.  To achieve this target, the bubble behaviors in the heat pump water heating system need to be extensively investigated. In this paper, by varying different experimental conditions, the effects of various heat pump hot water side parameters on gas microbubble diameters were measured and analyzed. Correspondingly, the effect of each parameter has been investigated. These include varied system pressures, water flow rates, saturation ratios and heat outputs. The results measurement showed that the water flow rate is the most significant parameter to influence on gas microbubble productions. The research outcomes can significantly contribute to the understanding of gas bubble behaviors at domestic heat pump water heating systems and thus the efficient way for the discharging of the associated dissolved gases.   <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=heat%20pump%20water%20heating%20system" title="heat pump water heating system">heat pump water heating system</a>, <a href="https://publications.waset.org/abstracts/search?q=microbubble%20formation" title=" microbubble formation"> microbubble formation</a>, <a href="https://publications.waset.org/abstracts/search?q=dissolved%20gases%20in%20water" title=" dissolved gases in water"> dissolved gases in water</a>, <a href="https://publications.waset.org/abstracts/search?q=effectiveness" title=" effectiveness"> effectiveness</a> </p> <a href="https://publications.waset.org/abstracts/64540/experimental-investigation-of-gas-bubble-behaviours-in-a-domestic-heat-pump-water-heating-system" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/64540.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">266</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">9178</span> An Experimental Investigation of the Variation of Evaporator Efficiency According to Load Amount and Textile Type in Hybrid Heat Pump Dryers</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Gokhan%20Sir">Gokhan Sir</a>, <a href="https://publications.waset.org/abstracts/search?q=Muhammed%20Ergun"> Muhammed Ergun</a>, <a href="https://publications.waset.org/abstracts/search?q=Onder%20Balioglu"> Onder Balioglu</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Nowadays, laundry dryers containing heaters and heat pumps are used to provide fast and efficient drying. In this system, as the drying capacity changes, the sensible and latent heat transfer rate in the evaporator changes. Therefore, the drying time measured for the unit capacity increases as the drying capacity decreases. The objective of this study is to investigate the evaporator efficiency according to load amount and textile type in hybrid heat pump dryers. Air side flow rate and system temperatures (air side and refrigeration side) were monitored instantly, and the specific moisture extraction rate (SMER), evaporator efficiency, and heat transfer mechanism between the textile and hybrid heat pump system were examined. Evaporator efficiency of heat pump dryers for cotton and synthetic based textile types in load amounts of 2, 5, 8 and 10 kg were investigated experimentally. As a result, the maximum evaporator efficiency (%72) was obtained in drying cotton and synthetic based textiles with a capacity of 5 kg; the minimum evaporator efficiency (%40) was obtained in drying cotton and synthetic based textiles with a capacity of 2 kg. The experimental study also reveals that capacity-dependent flow rate changes are the major factor for evaporator efficiency. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=evaporator" title="evaporator">evaporator</a>, <a href="https://publications.waset.org/abstracts/search?q=heat%20pump" title=" heat pump"> heat pump</a>, <a href="https://publications.waset.org/abstracts/search?q=hybrid" title=" hybrid"> hybrid</a>, <a href="https://publications.waset.org/abstracts/search?q=laundry%20dryer" title=" laundry dryer"> laundry dryer</a>, <a href="https://publications.waset.org/abstracts/search?q=textile" title=" textile"> textile</a> </p> <a href="https://publications.waset.org/abstracts/112239/an-experimental-investigation-of-the-variation-of-evaporator-efficiency-according-to-load-amount-and-textile-type-in-hybrid-heat-pump-dryers" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/112239.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">139</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">9177</span> Performance Analysis of Air Conditioning System Working on the Vapour Compression Refrigeration Cycle under Magnetohydrodynamic Influence</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Nikhil%20S.%20Mane">Nikhil S. Mane</a>, <a href="https://publications.waset.org/abstracts/search?q=Mukund%20L.%20Harugade"> Mukund L. Harugade</a>, <a href="https://publications.waset.org/abstracts/search?q=Narayan%20V.%20Hargude"> Narayan V. Hargude</a>, <a href="https://publications.waset.org/abstracts/search?q=Vishal%20P.%20Patil"> Vishal P. Patil</a> </p> <p class="card-text"><strong>Abstract:</strong></p> The fluids exposed to magnetic field can enhance the convective heat transfer by inducing secondary convection currents due to Lorentz force. The use of magnetohydrodynamic (MHD) forces in power generation and mass transfer is increasing steadily but its application to enhance the convective currents in fluids needed to be explored. The enhancement in convective heat transfer using MHD forces can be employed in heat exchangers, cooling of molten metal, vapour compression refrigeration (VCR) systems etc. The effective increase in the convective heat transfer without any additional energy consumption will lead to the energy efficient heat exchanging devices. In this work, the effect of MHD forces on the performance of air conditioning system working on the VCR system is studied. The refrigerant in VCR system is exposed to the magnetic field which influenced the flow of refrigerant. The different intensities of magnets are used on the different liquid refrigerants and investigation on performance of split air conditioning system is done under different loading conditions. The results of this research work show that the application of magnet on refrigerant flow has positive influence on the coefficient of performance (COP) of split air conditioning system. It is also observed that with increasing intensity of magnetic force the COP of split air conditioning system also increases. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=magnetohydrodynamics" title="magnetohydrodynamics">magnetohydrodynamics</a>, <a href="https://publications.waset.org/abstracts/search?q=heat%20transfer%20enhancement" title=" heat transfer enhancement"> heat transfer enhancement</a>, <a href="https://publications.waset.org/abstracts/search?q=VCRS" title=" VCRS"> VCRS</a>, <a href="https://publications.waset.org/abstracts/search?q=air%20conditioning" title=" air conditioning"> air conditioning</a>, <a href="https://publications.waset.org/abstracts/search?q=refrigeration" title=" refrigeration"> refrigeration</a> </p> <a href="https://publications.waset.org/abstracts/81030/performance-analysis-of-air-conditioning-system-working-on-the-vapour-compression-refrigeration-cycle-under-magnetohydrodynamic-influence" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/81030.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">212</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">9176</span> Performance of the Hybrid Loop Heat Pipe</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Nandy%20Putra">Nandy Putra</a>, <a href="https://publications.waset.org/abstracts/search?q=Imansyah%20Ibnu%20Hakim"> Imansyah Ibnu Hakim</a>, <a href="https://publications.waset.org/abstracts/search?q=Iwan%20Setyawan"> Iwan Setyawan</a>, <a href="https://publications.waset.org/abstracts/search?q=Muhammad%20Zayd%20A.I"> Muhammad Zayd A.I</a> </p> <p class="card-text"><strong>Abstract:</strong></p> A two-phase cooling technology of passive system sometimes can no longer meet the cooling needs of an increasingly challenging due to the inherent limitations of the capillary pumping for example in terms of the heat flux that can lead to dry out. In this study, intended to overcome the dry out with the addition of a diaphragm, they pump to accelerate the fluid transportation from the condenser to the evaporator. Diaphragm pump installed on the bypass line. When it did not happen dry out then the hybrid loop heat pipe will be work passively using a capillary pressure of wick. Meanwhile, when necessary, hybrid loop heat pipe will be work actively, using diaphragm pump with temperature control installed on the evaporator. From the results, it can be said that the pump has been successfully overcome dry out and can distribute working fluid from the condenser to the evaporator and reduce the temperature of the evaporator from 143°C to 100°C as a temperature controlled where the pump start actively at set point 100°C. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=hybrid" title="hybrid">hybrid</a>, <a href="https://publications.waset.org/abstracts/search?q=heat%20pipe" title=" heat pipe"> heat pipe</a>, <a href="https://publications.waset.org/abstracts/search?q=dry%20out" title=" dry out"> dry out</a>, <a href="https://publications.waset.org/abstracts/search?q=assisted" title=" assisted"> assisted</a>, <a href="https://publications.waset.org/abstracts/search?q=pump" title=" pump "> pump </a> </p> <a href="https://publications.waset.org/abstracts/32171/performance-of-the-hybrid-loop-heat-pipe" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/32171.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">352</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">9175</span> Numerical and Experimental Investigation of Impeller Trimming on Fluid Flow inside a Centrifugal Pump</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Rouhollah%20Torabi">Rouhollah Torabi</a>, <a href="https://publications.waset.org/abstracts/search?q=Ashkan%20Chavoshi"> Ashkan Chavoshi</a>, <a href="https://publications.waset.org/abstracts/search?q=Sheyda%20Almasi"> Sheyda Almasi</a>, <a href="https://publications.waset.org/abstracts/search?q=Shima%20Almasi"> Shima Almasi</a> </p> <p class="card-text"><strong>Abstract:</strong></p> In this paper the effect of impeller trim on centrifugal pump performance is studied and the most important effect which is decreasing the flow rate, differential head and efficiency is analyzed. For this case a low specific speed centrifugal pump is simulated with CFD. Total flow inside the pump including the secondary flow in sidewall gap which form internal leakage is modeled simultaneously in CFX software. The flow field in different area of pumps such as inside impeller, volute, balance holes and leakage through wear rings are studied. To validate the results experimental tests are done for various impeller diameters. Results also compared with analytic equations which predict pump performance with trimmed impeller. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=centrifugal%20pump" title="centrifugal pump">centrifugal pump</a>, <a href="https://publications.waset.org/abstracts/search?q=CFD" title=" CFD"> CFD</a>, <a href="https://publications.waset.org/abstracts/search?q=impeller" title=" impeller"> impeller</a>, <a href="https://publications.waset.org/abstracts/search?q=trim" title=" trim"> trim</a> </p> <a href="https://publications.waset.org/abstracts/24849/numerical-and-experimental-investigation-of-impeller-trimming-on-fluid-flow-inside-a-centrifugal-pump" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/24849.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">414</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">9174</span> Simulation of Internal Flow Field of Pitot-Tube Jet Pump</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Iqra%20Noor">Iqra Noor</a>, <a href="https://publications.waset.org/abstracts/search?q=Ihtzaz%20Qamar"> Ihtzaz Qamar</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Pitot-tube Jet pump, single-stage pump with low flow rate and high head, consists of a radial impeller that feeds water to rotating cavity. Water then enters stationary pitot-tube collector (diffuser), which discharges to the outside. By means of ANSYS Fluent 15.0, the internal flow characteristics for Pitot-tube Jet pump with standard pitot and curved pitot are studied. Under design condition, realizable k-e turbulence model and SIMPLEC algorithm are used to calculate 3D flow field inside both pumps. The simulation results reveal that energy is imparted to the flow by impeller and inside the rotor, forced vortex type flow is observed. Total pressure decreases inside pitot-tube whereas static pressure increases. Changing pitot-tube from standard to curved shape results in minimum flow circulation inside pitot-tube and leads to a higher pump performance. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=CFD" title="CFD">CFD</a>, <a href="https://publications.waset.org/abstracts/search?q=flow%20circulation" title=" flow circulation"> flow circulation</a>, <a href="https://publications.waset.org/abstracts/search?q=high%20pressure%20pump" title=" high pressure pump"> high pressure pump</a>, <a href="https://publications.waset.org/abstracts/search?q=impeller" title=" impeller"> impeller</a>, <a href="https://publications.waset.org/abstracts/search?q=internal%20flow" title=" internal flow"> internal flow</a>, <a href="https://publications.waset.org/abstracts/search?q=pickup%20tube%20pump" title=" pickup tube pump"> pickup tube pump</a>, <a href="https://publications.waset.org/abstracts/search?q=rectangle%20channels" title=" rectangle channels"> rectangle channels</a>, <a href="https://publications.waset.org/abstracts/search?q=rotating%20casing" title=" rotating casing"> rotating casing</a>, <a href="https://publications.waset.org/abstracts/search?q=turbulence" title=" turbulence"> turbulence</a> </p> <a href="https://publications.waset.org/abstracts/132118/simulation-of-internal-flow-field-of-pitot-tube-jet-pump" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/132118.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">160</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">9173</span> Hydraulic Optimization of an Adjustable Spiral-Shaped Evaporator</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Matthias%20Feiner">Matthias Feiner</a>, <a href="https://publications.waset.org/abstracts/search?q=Francisco%20Javier%20Fern%C3%A1ndez%20Garc%C3%ADa"> Francisco Javier Fernández García</a>, <a href="https://publications.waset.org/abstracts/search?q=Michael%20Arneman"> Michael Arneman</a>, <a href="https://publications.waset.org/abstracts/search?q=Martin%20Kipfm%C3%BCller"> Martin Kipfmüller</a> </p> <p class="card-text"><strong>Abstract:</strong></p> To ensure reliability in miniaturized devices or processes with increased heat fluxes, very efficient cooling methods have to be employed in order to cope with small available cooling surfaces. To address this problem, a certain type of evaporator/heat exchanger was developed: It is called a swirl evaporator due to its flow characteristic. The swirl evaporator consists of a concentrically eroded screw geometry in which a capillary tube is guided, which is inserted into a pocket hole in components with high heat load. The liquid refrigerant R32 is sprayed through the capillary tube to the end face of the blind hole and is sucked off against the injection direction in the screw geometry. Its inner diameter is between one and three millimeters. The refrigerant is sprayed into the pocket hole via a small tube aligned in the center of the bore hole and is sucked off on the front side of the hole against the direction of injection. The refrigerant is sucked off in a helical geometry (twisted flow) so that it is accelerated against the hot wall (centrifugal acceleration). This results in an increase in the critical heat flux of up to 40%. In this way, more heat can be dissipated on the same surface/available installation space. This enables a wide range of technical applications. To optimize the design for the needs in various fields of industry, like the internal tool cooling when machining nickel base alloys like Inconel 718, a correlation-based model of the swirl-evaporator was developed. The model is separated into 3 subgroups with overall 5 regimes. The pressure drop and heat transfer are calculated separately. An approach to determine the locality of phase change in the capillary and the swirl was implemented. A test stand has been developed to verify the simulation. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=helically-shaped" title="helically-shaped">helically-shaped</a>, <a href="https://publications.waset.org/abstracts/search?q=oil-free" title=" oil-free"> oil-free</a>, <a href="https://publications.waset.org/abstracts/search?q=R-32" title=" R-32"> R-32</a>, <a href="https://publications.waset.org/abstracts/search?q=swirl-evaporator" title=" swirl-evaporator"> swirl-evaporator</a>, <a href="https://publications.waset.org/abstracts/search?q=twist-flow" title=" twist-flow"> twist-flow</a> </p> <a href="https://publications.waset.org/abstracts/126336/hydraulic-optimization-of-an-adjustable-spiral-shaped-evaporator" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/126336.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">108</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">9172</span> Condensation Heat Transfer and Pressure Drop of R-134a Flowing inside Dimpled Tubes</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Kanit%20Aroonrat">Kanit Aroonrat</a>, <a href="https://publications.waset.org/abstracts/search?q=Somchai%20Wongwises"> Somchai Wongwises</a> </p> <p class="card-text"><strong>Abstract:</strong></p> A heat exchanger is one of the vital parts in a wide variety of applications. The tube with surface modification is generally referred to as an enhanced tube. With this, the thermal performance of the heat exchanger is improved. A dimpled tube is one of many kinds of enhanced tube. The heat transfer and pressure drop of two-phase flow inside dimpled tubes have received little attention in the literature, despite of having an important role in the development of refrigeration and air conditioning systems. As a result, the main aim of this study is to investigate the condensation heat transfer and pressure drop of refrigerant-134a flowing inside dimpled tubes. The test section is a counter-flow double-tube heat exchanger, which the refrigerant flows in the inner tube and water flows in the annulus. The inner tubes are one smooth tube and three dimpled tubes with different helical pitches. All test tubes are made from copper with an inside diameter of 8.1 mm and length of 1500 mm. The experiments are conducted over mass fluxes ranging from 300 to 500 kg/m²s, heat flux ranging from 10 to 20 kW/m², and condensing temperature ranging from 40 to 50 ˚C. The results show that all dimpled tubes provide higher heat transfer coefficient and frictional pressure drop compared to the smooth tube. In addition, the heat transfer coefficient and frictional pressure drop increase with decreasing of helical pitch. It can be observed that the dimpled tube with lowest helical pitch yields the heat transfer enhancement in the range of 60-89% with the frictional pressure drop increase of 289-674% in comparison to the smooth tube. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=condensation" title="condensation">condensation</a>, <a href="https://publications.waset.org/abstracts/search?q=dimpled%20tube" title=" dimpled tube"> dimpled tube</a>, <a href="https://publications.waset.org/abstracts/search?q=heat%20transfer" title=" heat transfer"> heat transfer</a>, <a href="https://publications.waset.org/abstracts/search?q=pressure%20drop" title=" pressure drop"> pressure drop</a> </p> <a href="https://publications.waset.org/abstracts/105152/condensation-heat-transfer-and-pressure-drop-of-r-134a-flowing-inside-dimpled-tubes" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/105152.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">215</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">9171</span> Variable Refrigerant Flow (VRF) Zonal Load Prediction Using a Transfer Learning-Based Framework</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Junyu%20Chen">Junyu Chen</a>, <a href="https://publications.waset.org/abstracts/search?q=Peng%20Xu"> Peng Xu</a> </p> <p class="card-text"><strong>Abstract:</strong></p> In the context of global efforts to enhance building energy efficiency, accurate thermal load forecasting is crucial for both device sizing and predictive control. Variable Refrigerant Flow (VRF) systems are widely used in buildings around the world, yet VRF zonal load prediction has received limited attention. Due to differences between VRF zones in building-level prediction methods, zone-level load forecasting could significantly enhance accuracy. Given that modern VRF systems generate high-quality data, this paper introduces transfer learning to leverage this data and further improve prediction performance. This framework also addresses the challenge of predicting load for building zones with no historical data, offering greater accuracy and usability compared to pure white-box models. The study first establishes an initial variable set of VRF zonal building loads and generates a foundational white-box database using EnergyPlus. Key variables for VRF zonal loads are identified using methods including SRRC, PRCC, and Random Forest. XGBoost and LSTM are employed to generate pre-trained black-box models based on the white-box database. Finally, real-world data is incorporated into the pre-trained model using transfer learning to enhance its performance in operational buildings. In this paper, zone-level load prediction was integrated with transfer learning, and a framework was proposed to improve the accuracy and applicability of VRF zonal load prediction. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=zonal%20load%20prediction" title="zonal load prediction">zonal load prediction</a>, <a href="https://publications.waset.org/abstracts/search?q=variable%20refrigerant%20flow%20%28VRF%29%20system" title=" variable refrigerant flow (VRF) system"> variable refrigerant flow (VRF) system</a>, <a href="https://publications.waset.org/abstracts/search?q=transfer%20learning" title=" transfer learning"> transfer learning</a>, <a href="https://publications.waset.org/abstracts/search?q=energyplus" title=" energyplus"> energyplus</a> </p> <a href="https://publications.waset.org/abstracts/191023/variable-refrigerant-flow-vrf-zonal-load-prediction-using-a-transfer-learning-based-framework" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/191023.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">28</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">9170</span> Numerical Simulation of Erosion Control in Slurry Pump Casing by Geometrical Flow Pattern Modification Analysis</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=A.%20R.%20Momeninezhad">A. R. Momeninezhad</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Erosion of Slurry Pumps in Related Industries, is one of the major costs in their production process. Many factories in extractive industries try to find ways to diminish this cost. In this paper, we consider the flow pattern modifications by geometric variations made of numerical simulation of flow inside pump casing, which is one of the most important parts analyzed for erosion. The mentioned pump is a cyclone centrifugal slurry pump, which is operating in Sarcheshmeh Copper Industries in Kerman-Iran, named and tagged as HM600 cyclone pump. Simulation shows many improvements in local wear information and situations for better and more qualified design of casing shape and impeller position, before and after geometric corrections. By theory of liquid-solid two-phase flow, the local wear defeats are analyzed and omitted. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=flow%20pattern" title="flow pattern">flow pattern</a>, <a href="https://publications.waset.org/abstracts/search?q=slurry%20pump" title=" slurry pump"> slurry pump</a>, <a href="https://publications.waset.org/abstracts/search?q=simulation" title=" simulation"> simulation</a>, <a href="https://publications.waset.org/abstracts/search?q=wear" title=" wear"> wear</a> </p> <a href="https://publications.waset.org/abstracts/24651/numerical-simulation-of-erosion-control-in-slurry-pump-casing-by-geometrical-flow-pattern-modification-analysis" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/24651.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">457</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">9169</span> Effect of Internal Heat Generation on Free Convective Power Law Variable Temperature Past Vertical Plate Considering Exponential Variable Viscosity and Thermal Diffusivity</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Tania%20Sharmin%20Khaleque">Tania Sharmin Khaleque</a>, <a href="https://publications.waset.org/abstracts/search?q=Mohammad%20Ferdows"> Mohammad Ferdows</a> </p> <p class="card-text"><strong>Abstract:</strong></p> The flow and heat transfer characteristics of a convection with temperature-dependent viscosity and thermal diffusivity along a vertical plate with internal heat generation effect have been studied. The plate temperature is assumed to follow a power law of the distance from the leading edge. The resulting governing two-dimensional equations are transformed using suitable transformations and then solved numerically by using fifth order Runge-Kutta-Fehlberg scheme with a modified version of the Newton-Raphson shooting method. The effects of the various parameters such as variable viscosity parameter β_1, the thermal diffusivity parameter β_2, heat generation parameter c and the Prandtl number Pr on the velocity and temperature profiles, as well as the local skin- friction coefficient and the local Nusselt number are presented in tabular form. Our results suggested that the presence of internal heat generation leads to increase flow than that of without exponentially decaying heat generation term. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=free%20convection" title="free convection">free convection</a>, <a href="https://publications.waset.org/abstracts/search?q=heat%20generation" title=" heat generation"> heat generation</a>, <a href="https://publications.waset.org/abstracts/search?q=thermal%20diffusivity" title=" thermal diffusivity"> thermal diffusivity</a>, <a href="https://publications.waset.org/abstracts/search?q=variable%20viscosity" title=" variable viscosity"> variable viscosity</a> </p> <a href="https://publications.waset.org/abstracts/57379/effect-of-internal-heat-generation-on-free-convective-power-law-variable-temperature-past-vertical-plate-considering-exponential-variable-viscosity-and-thermal-diffusivity" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/57379.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">353</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">9168</span> The Modification of the Mixed Flow Pump with Respect to Stability of the Head Curve</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Roman%20Klas">Roman Klas</a>, <a href="https://publications.waset.org/abstracts/search?q=Franti%C5%A1ek%20Pochyl%C3%BD"> František Pochylý</a>, <a href="https://publications.waset.org/abstracts/search?q=Pavel%20Rudolf"> Pavel Rudolf</a> </p> <p class="card-text"><strong>Abstract:</strong></p> This paper is focused on the CFD simulation of the radiaxial pump (i.e. mixed flow pump) with the aim to detect the reasons of Y-Q characteristic instability. The main reasons of pressure pulsations were detected by means of the analysis of velocity and pressure fields within the pump combined with the theoretical approach. Consequently, the modifications of spiral case and pump suction area were made based on the knowledge of flow conditions and the shape of dissipation function. The primary design of pump geometry was created as the base model serving for the comparison of individual modification influences. The basic experimental data are available for this geometry. This approach replaced the more complicated and with respect to convergence of all computational tasks more difficult calculation for the compressible liquid flow. The modification of primary pump consisted in inserting the three fins types. Subsequently, the evaluation of pressure pulsations, specific energy curves and visualization of velocity fields were chosen as the criterion for successful design. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=CFD" title="CFD">CFD</a>, <a href="https://publications.waset.org/abstracts/search?q=radiaxial%20pump" title=" radiaxial pump"> radiaxial pump</a>, <a href="https://publications.waset.org/abstracts/search?q=spiral%20case" title=" spiral case"> spiral case</a>, <a href="https://publications.waset.org/abstracts/search?q=stability" title=" stability"> stability</a> </p> <a href="https://publications.waset.org/abstracts/22872/the-modification-of-the-mixed-flow-pump-with-respect-to-stability-of-the-head-curve" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/22872.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">397</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">9167</span> Flow Field Analysis of a Liquid Ejector Pump Using Embedded Large Eddy Simulation Methodology</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Qasim%20Zaheer">Qasim Zaheer</a>, <a href="https://publications.waset.org/abstracts/search?q=Jehanzeb%20Masud"> Jehanzeb Masud</a> </p> <p class="card-text"><strong>Abstract:</strong></p> The understanding of entrainment and mixing phenomenon in the ejector pump is of pivotal importance for designing and performance estimation. In this paper, the existence of turbulent vortical structures due to Kelvin-Helmholtz instability at the free surface between the motive and the entrained fluids streams are simulated using Embedded LES methodology. The efficacy of Embedded LES for simulation of complex flow field of ejector pump is evaluated using ANSYS Fluent®. The enhanced mixing and entrainment process due to breaking down of larger eddies into smaller ones as a consequence of Vortex Stretching phenomenon is captured in this study. Moreover, the flow field characteristics of ejector pump like pressure velocity fields and mass flow rates are analyzed and validated against the experimental results. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=Kelvin%20Helmholtz%20instability" title="Kelvin Helmholtz instability">Kelvin Helmholtz instability</a>, <a href="https://publications.waset.org/abstracts/search?q=embedded%20LES" title=" embedded LES"> embedded LES</a>, <a href="https://publications.waset.org/abstracts/search?q=complex%20flow%20field" title=" complex flow field"> complex flow field</a>, <a href="https://publications.waset.org/abstracts/search?q=ejector%20pump" title=" ejector pump"> ejector pump</a> </p> <a href="https://publications.waset.org/abstracts/65909/flow-field-analysis-of-a-liquid-ejector-pump-using-embedded-large-eddy-simulation-methodology" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/65909.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">297</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">9166</span> Simulation of Ammonia-Water Two Phase Flow in Bubble Pump</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Jemai%20Rabeb">Jemai Rabeb</a>, <a href="https://publications.waset.org/abstracts/search?q=Benhmidene%20Ali"> Benhmidene Ali</a>, <a href="https://publications.waset.org/abstracts/search?q=Hidouri%20Khaoula"> Hidouri Khaoula</a>, <a href="https://publications.waset.org/abstracts/search?q=Chaouachi%20Bechir"> Chaouachi Bechir</a> </p> <p class="card-text"><strong>Abstract:</strong></p> The diffusion-absorption refrigeration cycle consists of a generator bubble pump, an absorber, an evaporator and a condenser, and usually operates with ammonia/water/ hydrogen or helium as the working fluid. The aim of this paper is to study the stability problem a bubble pump. In fact instability can caused a reduction of bubble pump efficiency. To achieve this goal, we have simulated the behaviour of two-phase flow in a bubble pump by using a drift flow model. Equations of a drift flow model are formulated in the transitional regime, non-adiabatic condition and thermodynamic equilibrium between the liquid and vapour phases. Equations resolution allowed to define void fraction, and liquid and vapour velocities, as well as pressure and mixing enthalpy. Ammonia-water mixing is used as working fluid, where ammonia mass fraction in the inlet is 0.6. Present simulation is conducted out for a heating flux of 2 kW/m² to 5 kW/m² and bubble pump tube length of 1 m and 2.5 mm of inner diameter. Simulation results reveal oscillations of vapour and liquid velocities along time. Oscillations decrease with time and with heat flux. For sufficient time the steady state is established, it is characterised by constant liquid velocity and void fraction values. However, vapour velocity does not have the same behaviour, it increases for steady state too. On the other hand, pressure drop oscillations are studied. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=bubble%20pump" title="bubble pump">bubble pump</a>, <a href="https://publications.waset.org/abstracts/search?q=drift%20flow%20model" title=" drift flow model"> drift flow model</a>, <a href="https://publications.waset.org/abstracts/search?q=instability" title=" instability"> instability</a>, <a href="https://publications.waset.org/abstracts/search?q=simulation" title=" simulation"> simulation</a> </p> <a href="https://publications.waset.org/abstracts/66839/simulation-of-ammonia-water-two-phase-flow-in-bubble-pump" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/66839.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">262</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">9165</span> Innovative Pump Design Using the Concept of Viscous Fluid Sinusoidal Excitation</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Ahmed%20H.%20Elkholy">Ahmed H. Elkholy</a> </p> <p class="card-text"><strong>Abstract:</strong></p> The concept of applying a prescribed oscillation to viscous fluids to aid or increase flow is used to produce a maintenance free pump. Application of this technique to fluids presents unique problems such as physical separation; control of heat and mass transfer in certain industrial applications; and improvement of some fluid process methods. The problem as stated is to obtain the velocity distribution, wall shear stress and energy expended when a pipe containing a stagnant viscous fluid is externally excited by a sinusoidal pulse, one end of the pipe being pinned. On the other hand, the effect of different parameters on the results are presented. Such parameters include fluid viscosity, frequency of oscillations and pipe geometry. It was found that the flow velocity through the pump is maximum at the pipe wall, and it decreases rapidly towards the pipe centerline. The frequency of oscillation should be above a certain value in order to obtain meaningful flow velocity. The amount of energy absorbed in the system is mainly due to pipe wall strain energy, while the fluid pressure and kinetic energies are comparatively small. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=sinusoidal%20excitation" title="sinusoidal excitation">sinusoidal excitation</a>, <a href="https://publications.waset.org/abstracts/search?q=pump" title=" pump"> pump</a>, <a href="https://publications.waset.org/abstracts/search?q=shear%20stress" title=" shear stress"> shear stress</a>, <a href="https://publications.waset.org/abstracts/search?q=flow" title=" flow"> flow</a> </p> <a href="https://publications.waset.org/abstracts/48529/innovative-pump-design-using-the-concept-of-viscous-fluid-sinusoidal-excitation" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/48529.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">315</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">9164</span> Effect of Flow Holes on Heat Release Performance of Extruded-Type Heat Sink</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Jung%20Hyun%20Kim">Jung Hyun Kim</a>, <a href="https://publications.waset.org/abstracts/search?q=Gyo%20Woo%20Lee"> Gyo Woo Lee</a> </p> <p class="card-text"><strong>Abstract:</strong></p> In this study, the enhancement of the heat release performance of an extruded-type heat sink to prepare the large-capacity solar inverter thru the flow holes in the base plate near the heat sources was investigated. Optimal location and number of the holes in the baseplate were determined by using a commercial computation program. The heat release performance of the shape-modified heat sink was measured experimentally and compared with that of the simulation. The heat sink with 12 flow holes in the 18-mm-thick base plate has a 8.1% wider heat transfer area, a 2.5% more mass flow of air, and a 2.7% higher heat release rate than those of the original heat sink. Also, the surface temperature of the base plate was lowered 1.5°C by the holes. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=heat%20sink" title="heat sink">heat sink</a>, <a href="https://publications.waset.org/abstracts/search?q=forced%20convection" title=" forced convection"> forced convection</a>, <a href="https://publications.waset.org/abstracts/search?q=heat%20transfer" title=" heat transfer"> heat transfer</a>, <a href="https://publications.waset.org/abstracts/search?q=performance%20evaluation" title=" performance evaluation"> performance evaluation</a>, <a href="https://publications.waset.org/abstracts/search?q=flow%20holes" title=" flow holes"> flow holes</a> </p> <a href="https://publications.waset.org/abstracts/8516/effect-of-flow-holes-on-heat-release-performance-of-extruded-type-heat-sink" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/8516.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">533</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">9163</span> Modelling and Simulation of the Freezing Systems and Heat Pumps Using Unisim® Design</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=C.%20Patrascioiu">C. Patrascioiu</a> </p> <p class="card-text"><strong>Abstract:</strong></p> The paper describes the modeling and simulation of the heat pumps domain processes. The main objective of the study is the use of the heat pump in propene–propane distillation processes. The modeling and simulation instrument is the Unisim<sup>®</sup> Design simulator. The paper is structured in three parts: An overview of the compressing gases, the modeling and simulation of the freezing systems, and the modeling and simulation of the heat pumps. For each of these systems, there are presented the Unisim<sup>®</sup> Design simulation diagrams, the input–output system structure and the numerical results. Future studies will consider modeling and simulation of the propene–propane distillation process with heat pump. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=distillation" title="distillation">distillation</a>, <a href="https://publications.waset.org/abstracts/search?q=heat%20pump" title=" heat pump"> heat pump</a>, <a href="https://publications.waset.org/abstracts/search?q=simulation" title=" simulation"> simulation</a>, <a href="https://publications.waset.org/abstracts/search?q=unisim%20design" title=" unisim design"> unisim design</a> </p> <a href="https://publications.waset.org/abstracts/42425/modelling-and-simulation-of-the-freezing-systems-and-heat-pumps-using-unisim-design" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/42425.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">363</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">9162</span> Experimental Analysis of the Plate-on-Tube Evaporator on a Domestic Refrigerator’s Performance</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Mert%20Tosun">Mert Tosun</a>, <a href="https://publications.waset.org/abstracts/search?q=Tu%C4%9Fba%20Tosun"> Tuğba Tosun</a> </p> <p class="card-text"><strong>Abstract:</strong></p> The evaporator is the utmost important component in the refrigeration system, since it enables the refrigerant to draw heat from the desired environment, i.e. the refrigerated space. Studies are being conducted on this component which generally affects the performance of the system, where energy efficient products are important. This study was designed to enhance the effectiveness of the evaporator in the refrigeration cycle of a domestic refrigerator by adjusting the capillary tube length, refrigerant amount, and the evaporator pipe diameter to reduce energy consumption. The experiments were conducted under identical thermal and ambient conditions. Experiment data were analysed using the Design of Experiment (DOE) technique which is a six-sigma method to determine effects of parameters. As a result, it has been determined that the most important parameters affecting the evaporator performance among the selected parameters are found to be the refrigerant amount and pipe diameter. It has been determined that the minimum energy consumption is 6-mm pipe diameter and 16-g refrigerant. It has also been noted that the overall consumption of the experiment sample decreased by 16.6% with respect to the reference system, which has 7-mm pipe diameter and 18-g refrigerant. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=heat%20exchanger" title="heat exchanger">heat exchanger</a>, <a href="https://publications.waset.org/abstracts/search?q=refrigerator" title=" refrigerator"> refrigerator</a>, <a href="https://publications.waset.org/abstracts/search?q=design%20of%20experiment" title=" design of experiment"> design of experiment</a>, <a href="https://publications.waset.org/abstracts/search?q=energy%20consumption" title=" energy consumption"> energy consumption</a> </p> <a href="https://publications.waset.org/abstracts/105362/experimental-analysis-of-the-plate-on-tube-evaporator-on-a-domestic-refrigerators-performance" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/105362.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">153</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">9161</span> Numerical Investigation of Flow Characteristics inside the External Gear Pump Using Urea Liquid Medium</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Kumaresh%20Selvakumar">Kumaresh Selvakumar</a>, <a href="https://publications.waset.org/abstracts/search?q=Man%20Young%20Kim"> Man Young Kim</a> </p> <p class="card-text"><strong>Abstract:</strong></p> In selective catalytic reduction (SCR) unit, the injection system is provided with unique dosing pump to govern the urea injection phenomenon. The urea based operating liquid from the AdBlue tank links up directly with the dosing pump unit to furnish appropriate high pressure for examining the flow characteristics inside the liquid pump. This work aims in demonstrating the importance of external gear pump to provide pertinent high pressure and respective mass flow rate for each rotation. Numerical simulations are conducted using immersed solid method technique for better understanding of unsteady flow characteristics within the pump. Parametric analyses have been carried out for the gear speed and mass flow rate to find the behavior of pressure fluctuations. In the simulation results, the outlet pressure achieves maximum magnitude with the increase in rotational speed and the fluctuations grow higher. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=AdBlue%20tank" title="AdBlue tank">AdBlue tank</a>, <a href="https://publications.waset.org/abstracts/search?q=external%20gear%20pump" title=" external gear pump"> external gear pump</a>, <a href="https://publications.waset.org/abstracts/search?q=immersed%20solid%20method" title=" immersed solid method"> immersed solid method</a>, <a href="https://publications.waset.org/abstracts/search?q=selective%20catalytic%20reduction" title=" selective catalytic reduction"> selective catalytic reduction</a> </p> <a href="https://publications.waset.org/abstracts/69334/numerical-investigation-of-flow-characteristics-inside-the-external-gear-pump-using-urea-liquid-medium" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/69334.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">280</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">9160</span> Flow Boiling Heat Transfer at Low Mass and Heat Fluxes: Heat Transfer Coefficient, Flow Pattern Analysis and Correlation Assessment</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Ernest%20Gyan%20Bediako">Ernest Gyan Bediako</a>, <a href="https://publications.waset.org/abstracts/search?q=Petra%20Dancova"> Petra Dancova</a>, <a href="https://publications.waset.org/abstracts/search?q=Tomas%20Vit"> Tomas Vit</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Flow boiling heat transfer remains an important area of research due to its relevance in thermal management systems and other applications. Despite the enormous work done in the field of flow boiling heat transfer over the years to understand how flow parameters such as mass flux, heat flux, saturation conditions and tube geometries influence the characteristics of flow boiling heat transfer, there are still many contradictions and lack of agreement on the actual mechanisms controlling heat transfer and how flow parameters impact the heat transfer. This work thus seeks to experimentally investigate the heat transfer characteristics and flow patterns at low mass fluxes, low heat fluxes and low saturation pressure conditions which are of less attention in literature but prevalent in refrigeration, air-conditioning and heat pump applications. In this study, flow boiling experiment was conducted for R134a working fluid in a 5 mm internal diameter stainless steel horizontal smooth tube with mass flux ranging from 80- 100 kg/m2 s, heat fluxes ranging from 3.55kW/m2 - 25.23 kW/m2 and saturation pressure of 460 kPa. Vapor quality ranged from 0 to 1. A well-known flow pattern map created by Wojtan et al. was used to predict the flow patterns noticed during the study. The experimental results were correlated with well-known flow boiling heat transfer correlations in literature. The findings show that, heat transfer coefficient was influenced by both mass flux and heat fluxes. However, for an increasing heat flux, nucleate boiling was observed to be the dominant mechanism controlling the heat transfer especially at low vapor quality region. For an increasing mass flux, convective boiling was the dominant mechanism controlling the heat transfer especially in the high vapor quality region. Also, the study observed an unusual high heat transfer coefficient at low vapor qualities which could be due to periodic wetting of the walls of the tube due to slug flow pattern and stratified wavy flow patterns. The flow patterns predicted by Wojtan et al. flow pattern map were mixture of slug and stratified wavy, purely stratified wavy and dry out. Statistical assessment of the experimental data with various well-known correlations from literature showed that, none of the correlations reported in literature could predicted the experimental data with enough accuracy. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=flow%20boiling" title="flow boiling">flow boiling</a>, <a href="https://publications.waset.org/abstracts/search?q=heat%20transfer%20coefficient" title=" heat transfer coefficient"> heat transfer coefficient</a>, <a href="https://publications.waset.org/abstracts/search?q=mass%20flux" title=" mass flux"> mass flux</a>, <a href="https://publications.waset.org/abstracts/search?q=heat%20flux." title=" heat flux."> heat flux.</a> </p> <a href="https://publications.waset.org/abstracts/157649/flow-boiling-heat-transfer-at-low-mass-and-heat-fluxes-heat-transfer-coefficient-flow-pattern-analysis-and-correlation-assessment" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/157649.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">116</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">9159</span> Performance Analysis of High Temperature Heat Pump Cycle for Industrial Process</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Seon%20Tae%20Kim">Seon Tae Kim</a>, <a href="https://publications.waset.org/abstracts/search?q=Robert%20Hegner"> Robert Hegner</a>, <a href="https://publications.waset.org/abstracts/search?q=Goksel%20Ozuylasi"> Goksel Ozuylasi</a>, <a href="https://publications.waset.org/abstracts/search?q=Panagiotis%20Stathopoulos"> Panagiotis Stathopoulos</a>, <a href="https://publications.waset.org/abstracts/search?q=Eberhard%20Nicke"> Eberhard Nicke</a> </p> <p class="card-text"><strong>Abstract:</strong></p> High-temperature heat pumps (HTHP) that can supply heat at temperatures above 200°C can enhance the energy efficiency of industrial processes and reduce the CO₂ emissions connected with the heat supply of these processes. In the current work, the thermodynamic performance of 3 different vapor compression cycles, which use R-718 (water) as a working medium, have been evaluated by using a commercial process simulation tool (EBSILON Professional). All considered cycles use two-stage vapor compression with intercooling between stages. The main aim of the study is to compare different intercooling strategies and study possible heat recovery scenarios within the intercooling process. This comparison has been carried out by computing the coefficient of performance (COP), the heat supply temperature level, and the respective mass flow rate of water for all cycle architectures. With increasing temperature difference between the heat source and heat sink, ∆T, the COP values decreased as expected, and the highest COP value was found for the cycle configurations where both compressors have the same pressure ratio (PR). The investigation on the HTHP capacities with optimized PR and exergy analysis has also been carried out. The internal heat exchanger cycle with the inward direction of secondary flow (IHX-in) showed a higher temperature level and exergy efficiency compared to other cycles. Moreover, the available operating range was estimated by considering mechanical limitations. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=high%20temperature%20heat%20pump" title="high temperature heat pump">high temperature heat pump</a>, <a href="https://publications.waset.org/abstracts/search?q=industrial%20process" title=" industrial process"> industrial process</a>, <a href="https://publications.waset.org/abstracts/search?q=vapor%20compression%20cycle" title=" vapor compression cycle"> vapor compression cycle</a>, <a href="https://publications.waset.org/abstracts/search?q=R-718%20%28water%29" title=" R-718 (water)"> R-718 (water)</a>, <a href="https://publications.waset.org/abstracts/search?q=thermodynamic%20analysis" title=" thermodynamic analysis"> thermodynamic analysis</a> </p> <a href="https://publications.waset.org/abstracts/136516/performance-analysis-of-high-temperature-heat-pump-cycle-for-industrial-process" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/136516.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">149</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">9158</span> A Note on MHD Flow and Heat Transfer over a Curved Stretching Sheet by Considering Variable Thermal Conductivity </h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=M.%20G.%20Murtaza">M. G. Murtaza</a>, <a href="https://publications.waset.org/abstracts/search?q=E.%20E.%20Tzirtzilakis"> E. E. Tzirtzilakis</a>, <a href="https://publications.waset.org/abstracts/search?q=M.%20Ferdows"> M. Ferdows</a> </p> <p class="card-text"><strong>Abstract:</strong></p> The mixed convective flow of MHD incompressible, steady boundary layer in heat transfer over a curved stretching sheet due to temperature dependent thermal conductivity is studied. We use curvilinear coordinate system in order to describe the governing flow equations. Finite difference solutions with central differencing have been used to solve the transform governing equations. Numerical results for the flow velocity and temperature profiles are presented as a function of the non-dimensional curvature radius. Skin friction coefficient and local Nusselt number at the surface of the curved sheet are discussed as well. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=curved%20stretching%20sheet" title="curved stretching sheet">curved stretching sheet</a>, <a href="https://publications.waset.org/abstracts/search?q=finite%20difference%20method" title=" finite difference method"> finite difference method</a>, <a href="https://publications.waset.org/abstracts/search?q=MHD" title=" MHD"> MHD</a>, <a href="https://publications.waset.org/abstracts/search?q=variable%20thermal%20conductivity" title=" variable thermal conductivity"> variable thermal conductivity</a> </p> <a href="https://publications.waset.org/abstracts/85972/a-note-on-mhd-flow-and-heat-transfer-over-a-curved-stretching-sheet-by-considering-variable-thermal-conductivity" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/85972.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">195</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">9157</span> Thermodynamics Analysis of Transcritical HTHP Cycles Using Eco-Friendly Refrigerant and low-Grade Waste Heat Recovery: A Theoretical Evaluation</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Adam%20Y.%20Sulaiman">Adam Y. Sulaiman</a>, <a href="https://publications.waset.org/abstracts/search?q=Donal%20F.%20Cotter"> Donal F. Cotter</a>, <a href="https://publications.waset.org/abstracts/search?q=Ming%20J.%20Huang"> Ming J. Huang</a>, <a href="https://publications.waset.org/abstracts/search?q=Neil%20J.%20Hewitt"> Neil J. Hewitt</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Decarbonization of the industrial sector in developed countries has become indispensable for addressing climate change. Industrial processes including drying, distillation, and injection molding require a process heat exceeding 180°C, rendering the subcriticalHigh-Temperature heat pump(HTHP) technique unsuitable. A transcritical HTHP utilizing ecologically friendly working fluids is a highly recommended system that incorporates the features of high-energy efficiency, extended operational range, and decarbonizing the industrial sector. This paper delves into the possibility and feasibility of leveraging the HTTP system to provide up to 200°C of heat using R1233zd(E) as a working fluid. Using a steady-state model, various transcritical HTHP cycle configurations aretheoretically compared,analyzed, and evaluatedin this study. The heat transfer characteristics for the evaporator and gas cooler are investigated, as well as the cycle's energy, exergetic, and environmental performance. Using the LMTD method, the gas cooler's heat transfer coefficient, overall length, and heat transfer area were calculated. The findings indicate that the heat sink pressure level, as well as the waste heat temperature provided to the evaporator, have a significant impact on overall cycle performance. The investigation revealed the potential challenges and barriers, including the length of the gas cooler and the lubrication of the compression process. The basic transcritical HTTP cycle with additional IHX was demonstrated to be the most efficient cycle across a variety of heat source temperatures ranging from 70 to 90 °C based on theoretical energetic and exergetic performance. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=high-temperature%20heat%20pump" title="high-temperature heat pump">high-temperature heat pump</a>, <a href="https://publications.waset.org/abstracts/search?q=transcritical%20cycle" title=" transcritical cycle"> transcritical cycle</a>, <a href="https://publications.waset.org/abstracts/search?q=refrigerants" title=" refrigerants"> refrigerants</a>, <a href="https://publications.waset.org/abstracts/search?q=gas%20cooler" title=" gas cooler"> gas cooler</a>, <a href="https://publications.waset.org/abstracts/search?q=energy" title=" energy"> energy</a>, <a href="https://publications.waset.org/abstracts/search?q=exergy" title=" exergy"> exergy</a> </p> <a href="https://publications.waset.org/abstracts/146603/thermodynamics-analysis-of-transcritical-hthp-cycles-using-eco-friendly-refrigerant-and-low-grade-waste-heat-recovery-a-theoretical-evaluation" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/146603.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">163</span> </span> </div> </div> <ul class="pagination"> <li class="page-item disabled"><span class="page-link">&lsaquo;</span></li> <li class="page-item active"><span class="page-link">1</span></li> <li class="page-item"><a class="page-link" href="https://publications.waset.org/abstracts/search?q=variable%20refrigerant%20flow%20heat%20pump&page=2">2</a></li> <li class="page-item"><a class="page-link" href="https://publications.waset.org/abstracts/search?q=variable%20refrigerant%20flow%20heat%20pump&page=3">3</a></li> <li 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