The thermodynamic aspect of a compression type heat pump （HP） is briefly described and special attention is given to investigation of condensing temperature influence on heat pump efficiency in heating mode, express...The thermodynamic aspect of a compression type heat pump （HP） is briefly described and special attention is given to investigation of condensing temperature influence on heat pump efficiency in heating mode, expressed by its coefficient of performance （COP）. Heat pumps are usually applied for the purposes of heating and cooling of energy efficient buildings where they have advantages in low-temperature systems, as it is well documented in the paper. The comparison of real thermodynamic processes with thermodynamically most favorable Camot＇s process is made. The results in the paper show that COP is diminishing with increasing of condensing temperature and also depends on real properties of working fluids. The impact of compressor efficiency for two real working media is also analyzed in the paper. There is significant diminishing of COP with diminishing of compressor efficiency. The intension of the paper is to help better understanding of this very effective and prosperous technology, and to encourage its development, production, and efficient application.展开更多
In this study the performance of an ASHPWH （air source heat pump water heater） is assessed from exergy point of view in component wise. In order to investigate the work potential of energy, the destruction on the ex...In this study the performance of an ASHPWH （air source heat pump water heater） is assessed from exergy point of view in component wise. In order to investigate the work potential of energy, the destruction on the exergy is analyzed and results are summarized for the components individually. The exergy destruction of the system is studied by considering real paths of the pressure and temperature data which are collected during the experiments of the ASHPWH under varying environmental conditions. In the following step, the evolution of the exergy destruction of the system is calculated by a code which is compiled on MATLAB along these temperature and pressure paths. The obtained results reveal the importance of the transient exergy analysis by providing detailed information about exergy destruction of the system such as where it drives up and reaches up to its max and where it drops down and evolves on a smooth path.展开更多
文摘The thermodynamic aspect of a compression type heat pump （HP） is briefly described and special attention is given to investigation of condensing temperature influence on heat pump efficiency in heating mode, expressed by its coefficient of performance （COP）. Heat pumps are usually applied for the purposes of heating and cooling of energy efficient buildings where they have advantages in low-temperature systems, as it is well documented in the paper. The comparison of real thermodynamic processes with thermodynamically most favorable Camot＇s process is made. The results in the paper show that COP is diminishing with increasing of condensing temperature and also depends on real properties of working fluids. The impact of compressor efficiency for two real working media is also analyzed in the paper. There is significant diminishing of COP with diminishing of compressor efficiency. The intension of the paper is to help better understanding of this very effective and prosperous technology, and to encourage its development, production, and efficient application.
文摘In this study the performance of an ASHPWH （air source heat pump water heater） is assessed from exergy point of view in component wise. In order to investigate the work potential of energy, the destruction on the exergy is analyzed and results are summarized for the components individually. The exergy destruction of the system is studied by considering real paths of the pressure and temperature data which are collected during the experiments of the ASHPWH under varying environmental conditions. In the following step, the evolution of the exergy destruction of the system is calculated by a code which is compiled on MATLAB along these temperature and pressure paths. The obtained results reveal the importance of the transient exergy analysis by providing detailed information about exergy destruction of the system such as where it drives up and reaches up to its max and where it drops down and evolves on a smooth path.
