FIRST AND SECOND LAW ANALYSIS OF A LABORATORY AMMONIA/WATER ABSORPTION HEAT PUMP

• Published in: International journal of air-conditioning and refrigeration 2010, 18(2), , pp.117-129
• Main Authors: MOSER, HARALD, RIEBERER, RENÉ
• Format: Article
• Language: English
• Subjects: 기계공학
• ISSN: 2010-1325; 2010-1333
• DOI: 10.1142/S2010132510000253

At the Institute of Thermal Engineering, a small-capacity ammonia/water absorption heat pumping unit with about 5 kW cooling capacity has been constructed and tested in the laboratory. For all heat exchangers, standard plate heat exchangers have been used. The heat pump has been designed to operate in a wide operating range in order to enable different temperature levels for ice production, residential cooling, and heating applications. To identify potential for improvements, a thermodynamic analysis using both the first and the second law of thermodynamics has been carried out in order to locate irreversibilities associated with inefficient processes and to calculate the exergy loss of each component. Therefore the exergy losses of the main components have been separated into one part which is caused by the heat transfer and another part which originates from internal irreversibilities, e.g., from mixing processes. Furthermore, sensitivity calculations have been performed by varying the temperature levels of the heat sources and the heat sink in order to investigate the different component losses at different operating conditions. The results show that the component exergy losses depend particular on the temperature level of both the heat sources and the heat sink. At low temperature lifts, the exergy losses of the absorber and generator are dominant and with increasing temperature lift, the exergy losses of the dephlegmator and the rectification column become considerable.