Research On The Applicability Of Residential Fresh Air Dehumidification Hot Water Tri-function Heat Pump System

Conventional air conditioning system has the problems of energy waste and low comfort.Therefore,in recent years,the air conditioning system with independent control of temperature and humidity has become one of the hot directions in the field of HVAC due to its comfort and energy saving.However,at present,the research on the air conditioning system of independent control of temperature and humidity at home and abroad is mainly focused on public buildings and industrial buildings,and there are few researches on residential buildings.In addition,the existing researches also fail to consider the annual demand of residential hot water.In this paper,a household air conditioning hot water system with independent control of temperature and humidity is proposed for residential buildings.The system uses fresh air to bear the wet load of the house,as well as fresh air and domestic hot water load throughout the year.The paper introduces the working principle of the system.The application area is analyzed.In this paper,four high humidity cities,Guangzhou,Changsha,Hangzhou and Shanghai,were selected to do further research,and the influence of operation mode and exhaust heat exchanger on system performance was analyzed.The method of selecting the design parameters of outdoor air in summer is given.It is found that the system is suitable for hot summer and warm winter zone,mild region,hot summer and cold winter zone,and some cities in the severe cold region of the Yangtze river basin.The condensation heat recovery rate in the all-day operation mode was higher than that in the night-time operation mode,that means the system was more capable of cooling and heating at the same time.The recovery rate of condensation heat in Guangzhou is as high as 77.2%,and that in Shanghai and Changsha are above 60%.Besides,the recovery rate of condensation heat in Hangzhou is 59.45%.The energy saving effect of total heat exchanger is better than that of sensible heat exchanger.However,the energy-saving effect is affected by the operation mode and season,and the energy-saving effect is better under the all-day operation mode.When using the full heat exchanger,the energy saving rate in winter is higher than that in summer.In the transition season,Hangzhou and Guangzhou are energy-saving in the all-day operation mode,but not in the night-time operation mode,while Shanghai and Changsha are energy-saving in both modes,but the energy-saving rate decreases in the night-time operation mode.By comparing the outdoor meteorological parameters in the past 30 years,it is found that the existing outdoor design parameters of air conditioning in summer cannot meet the design requirements of the new air hot water three-in-one multi-functional heat pump system.Therefore,the selection standard of outdoor air design parameters in summer should be adjusted to not guarantee the dry bulb temperature and moisture content of50 h.The air enthalpy value corresponding to this design parameter is higher than the air enthalpy value corresponding to the outdoor design parameter of existing summer airconditioning,and the difference value is within 5k J/kg.