Evaluation of optimal subcooling in subcritical heat pump systems
| Autor: | José Gonzálvez-Maciá, Emilio Navarro-Peris, Estefanía Hervas-Blasco, José M. Corberán, Miquel Pitarch |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
Optimal working point
Materials science 020209 energy Thermodynamics 02 engineering and technology Heat sink Transcritical cycle law.invention Refrigerant Heat exchanger design Thermal expansion valve 020401 chemical engineering Economizer law Flash-gas 0202 electrical engineering electronic engineering information engineering 0204 chemical engineering Heat pump Subcooling Mechanical Engineering Natural refrigerants Building and Construction Mechanics 6. Clean water FISICA APLICADA MAQUINAS Y MOTORES TERMICOS |
| Zdroj: | RiuNet. Repositorio Institucional de la Universitat Politécnica de Valéncia instname |
| Popis: | [EN] The performance of a transcritical cycle is highly dependent on the rejection pressure. The optimal rejection pressure depends mainly on the inlet and outlet temperatures at the heat sink (secondary fluid). For the subcritical cycles, recent studies have demonstrated that the performance of these systems depends significantly on the degree of subcooling and its optimal value varies depending on the application. This paper presents a general methodology to calculate the optimal subcooling depending on the boundary conditions. The refrigerants R290, R134a, R1234yf and R32 are analyzed. Exergy analysis is used in order to see the subcooling effect at condenser and expansion valve independently. The optimal subcooling strongly depends on the temperature lift at the secondary fluid, and it is found when two pinch points are given in the condenser, one at the condenser outlet and another one inside the condenser (at the refrigerant dew point). Part of the results of this study were developed in the mainframe of the FP7 European project "Next Generation of Heat Pumps working with Natural fluids" (NxtHPG). Part of the work presented was carried by Miguel Pitarch-Mocholi with the financial support of the PhD scholarship from the Universitat Politecnica de Valencia. The authors would like to acknowledge the Spanish "MINISTERIO DE ECONOMIA Y COMPETITIVIDAD", through the project ref-ENE2014-53311-C2-1-P-AR "Aprovechamiento del calor residual a baja temperatura mediante bombas de calor para la produccion de agua caliente" for the given support. |
| Databáze: | OpenAIRE |
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