Thermal And Economic Performance Of A Solar Membrane Liquid Desiccant Air Conditioning System

Refrigeration and air-conditioning equipment is increasingly widely used under the premise of development in people's living standards and economic.But there are a lot of problems caused by air-conditioning equipment,such as destruction of the environment,reduction of the quality of gas,energy shortages and so on.Therefore,there are increasingly demand to research and develop new energy-saving,environmental protection and comfortable and healthy air-conditioning system.And liquid desiccant air conditioning system received more and more attention in recent years.This is mainly because the liquid desiccant air conditioning system can be more efficient control of humidity,more strong in desiccant performance,more environmentally friendly compared to traditional air conditioning systems.It has a low power consumption,can be operated under full air,and the system can use low grade heat source.In addition,the system can also get rid of bacteria,dust and other harmful substances of the air.Thus,we are increasingly being widely use liquid desiccant air conditioning systems,allowing this system to dehumidify fresh air.This paper presents a solar membrane liquid desiccant air conditioning system to research.In the solar membrane liquid desiccant air conditioning system,the liquid-to-air membrane energy exchanger is used for humid air dehumidification and dilute desiccant solution regeneration.The presence of dehumidifier droplets in supply air and exhaust air limits the use of direct-contact liquid desiccant air conditioning systems in commercial and residential applications.The liquidto-air membrane energy exchanger can solve this problem because it uses a semipermeable membrane to separate the air and the liquid so as to heat and heat it without touching the liquid dehumidifier.In this paper,TRNSYS building energy simulation software is used to simulate eight different system configurations,which are mainly different in heating systems and air systems.4 heating systems are as follows:(1)natural gas boiler.(2)electric heat pump.(3)solar thermal system with natural gas boiler for spare.(4)solar thermal system with electric heat pump for backup.Studied two air systems: one with an energy recovery ventilator,and the other without.The influence of the collector area and storage volume of hot water tank relative to collector area on the annual solar fraction,annual collector efficiency and life cycle cost are studied by parametric method.The size of the solar thermal system allows the system to minimize the life cycle cost and to assess the economic and environmental performance of the system by calculating initial costs,annual operating costs,life cycle costs,payback periods and annual carbon dioxide emissions.The results show that the use of solar thermal systems to meet the thermal energy required to regenerate the diluted dehumidifier liquid can significantly enhance the economic and environmental performance of the system and when using a natural gas boiler as a backup heating system and without using an energy recovery ventilator the effect is more obvious.