| To make use of the dehumidification and air cleaning effect of silica gel rotor andthe efficient heat transfer effect of heat pump, the high temperature heat pump anddesiccant wheel (HTHP&DW) air conditioning system is put forward. Energy on bothsides of the heat pump is fully used and contributes to the cooling process. Thecondensing heat from the condenser is used to regenerate the rotor and theevaporating heat from the evaporator is used to cool the process air. Within the system,the sensible and latent heat load are handled independently and the balance betweenheat and cold and the self-regeneration are achieved, which can reduce theenvironment impact and save energy.Three integrated designs for summer and winter use are provided based on thetheory analysis and the experimental investigation is carried out for the feasibility ofone-stage and two-stage air conditioning system. One-stage HTHP&DW system isadopted and its corresponding air conditioning unit is built.Theoretical and experimental analysis of a new refrigerant mixtures named BY-3is conducted and its function of high efficient heat collect is approved. Consideringthe dehumidification effect of desiccant wheel, the experimental investigation of thecoupling of heat pump to solid desiccant rotor is carried out. The results shows thatthe maximum adiabatic efficiency is obtained when the regeneration temperature isbetween60~65℃. Then the experiment on HTHP&DW system is conducted in theextensive hot and humid environment. It is demonstrated, when mixture refrigerant ofBY-3is involved in the air source heat pump, the supply air temperatures are in therange of20±1℃as expected except that when in the extreme hot environment(above36℃) and the regeneration temperatures can satisfy the regenerationrequirement of desiccant without adding any heat. Also it is found that outdoor airtemperature, humidity ratio and regeneration air flow rate have great impact on theperformance of heat pump based on the coefficient of performance (COP) evaluated.The maximum COP of heat pump for cooling is2.26and that for heating is2.76. Theaverage dehumidification efficiency of HTHP&DW system is32.7%in summer.The performance of desiccant wheel in the running HTHP&DW system isevaluated based on the indexes of moisture removal capacity, dehumidification effectiveness, dehumidification coefficient of performance and sensible energy ratio.The results show that the higher effect on the dehumidification capability is due to theregeneration temperature and outdoor air humidity ratio rather than the outdoor airtemperature and the ratio between regeneration and process air flow rates. Besides,regression models between the performance indexes and variables are obtained whichcan be used to easily predict the behavior of desiccant wheel. The experiment data andpredicted amounts are compared and satisfactory consistencies are achieved.The result of exergy analysis shows that the exergy efficiency of the compressoris the lowest which should be improved; exergy efficiency of whole system is8.17%that167%greater than the system with additional heater, which significant improvesthe efficiency of energy use.A simulated program of traditional compress-vapor air conditioning system ismade with VB. Comparing the performance of HTHP&DW system with traditionalsystem, the energy saving is up to38.8%in the typical condition. It is also found thatthe potential of energy saving is greater in the hot dry environment than in the hothumid environment. |
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