The Properties Research On Compound Condensation/Evaporation Of Four Functional Heat Pump

With the development of heat pump technology, it has been widely used as building cooling and heating source in recent years.And due to small initial investment, convenient installation,the air-source heat pump, which is specially suitable for the medium and small public buildings,has been widely used in most parts of China. However, the air-source heat pump will bring about a mount of heat emissions,which will cause environmental thermal pollution as well as a waste of energy. At the same time, the air evaporator is easy to frost and the efficiency is low when the unit works in conditions of high humidity in cold winter. For the shortcomings of the air source heat pump,a compound condensation/evaporation of four functional heat pump is designed in this paper, which is able to recover condensating heat for sanitary hot water and avoid frosting.Finally, theoretical and experimental analysis has been done for its performance,which proves this unit a novel multi-function heat pump of energy conservation and enviromental protection.The structure of the compound condensation/evaporation heat pump of four functions was designed in this paper. And the operating condition modes as well as the technical features and advantages were introduced.According to the above,the air-source heat pump unit was modified.And an experimental system was also built, which included water system and control system.In this paper, the exergy method was brought in for analyzing the performance of this system.Due to the exergy metod, each part model was built.as well as some exergy flow diagrams of the unit were draw under different working modes.And then Analog simulations were made with simulink for the unit analysis.The exergy loss of the components and exergy efficiency of the unit were analyzed with condensing and evaporating temperature changing under conventional condensation,evaporation mode.also the temperature of sanitary hot water, exergy loss and efficiency of the unit change over time were analyzed under refrigeration-sanitary hot water and sanitary hot water modes.According to the results, The unit exergy efficiency increased by 5% during the refrigeration-sanitary hot water mode,while it increased by 30% under the sanitary hot water mode.To analyze the performance for the unit, experiments were made for the changes of performance parameters.Accoring to the results, it was concluded that the integrated coefficient of performance is greatly improved opposed to the conventional air-source heat pump,and it is about 1-fold.Comparing the experimental results with simulation ones,the changes of the unit performance are basically the same.