The Study Of Solar Energy And Ground Source Heat Pump Air-conditioning System Based On The Liquid Desiccant

In recent years, in the research and development of green energy technologies, solar energy and shallow geothermal energy had been applied more and more widely in the field of the building energy conservation, and had been widely recognized and favored by everyone. Although solar energy and shallow geothermal energy are clean energy, and all widely exist, but with the deepening and exploration of the application, we will find that if we just have a single use of the shallow geothermal energy or solar energy, that all have some defects. Although solar energy is inexhaustible, it is affected by the seasons, time, location and other factors, these problems caused the energy flow density of solar radiation instability and the discontinuities of its application; while the shallow soil store a large amount of low taste heat, if we only use this part of heat, it will cause unbalance problems of the underground heat, especially in the cold region of the north of China, if this continues, the average soil temperature will decrease, at the same time, it increase the burden of heat pump unit and it also increases energy consumption. This research is intended to make a comprehensive application of solar energy technology, heat pump technology and liquid dehumidification technology in the field of building energy conservation, the combined use of the three technology, to achieve complementary advantages, and ultimately achieve the purpose of energy saving and environmental protection.This paper selects a certain office building of Ji’nan as the construction model, using TYPE56 module of TRNSYS software, set specific parameters of the model according to the actual situation of the building, and we get the maximum cooling load is 342.27kw, the maximum heat load is 260.91kw, and the accumulation of heat absorption and accumulation of heat dissipation are imbalance, the imbalance rate reached 22%, and by the simulation we know that the cumulate amount of latent heat load in summer accounted for 42.4%. According to the office building, we use the software of TRNSYS to establish the simulation system of ground source heat pump that run separately, to simulate the changes of parameters of the system operating 1 year and 20 year. According to the simulation we will find that with the longer running time, the inlet and outlet water temperature of the buried pipe showed a downward trend, and the energy efficiency value of ground source heat pump unit also has a downward trend year by year, the soil temperature also has an obvious downward trend, the soil temperature fall from the initial setting temperature 15.2 degrees to 12.5 degrees, the decreasing amplitude is 17.8%.Because Ji’nan is located in the zone of hot summer and cold winter, and the humidity is bigger, in view of the imbalance problem of the hot and cold when the ground source heat pump running separately, this paper set up the solar energy and ground source heat pump air-conditioning system based on the liquid desiccant on this basis. In summer, we use liquid desiccant to undertake the heat load of building, and the solar energy as the heat source of the regeneration, allow the ground source heat pump refrigerating in high temperature conditions; In winter,we use the recharging technology of solar energy to assist ground source heat pump heating, to improve the performance of heat pumps. Through the establishment of solar energy and ground source heat pump system, using TRNSYS software to simulate the system operation situation of composite system in high temperature and low temperature conditions. Through the simulation, the thermal efficiency of the collector in the heating season is between 0.3～0.5, it can match well with the solar energy and heat pump system; The solar energy and ground source heat pump system can solve the perennial declined problems of the ground resulting from the heat pump run alone year by year, the average temperature of the soil is stable at about 15.2℃; and the water temperature of the inlet and outlet of the buried tube and the energy efficiency values of heat pump are maintained at a relatively stable state, but through the comparison we can see that, the composite system with liquid desiccant compared with the conventional ground source heat pump system is:in summer, the COP of heat pump unit increased from 5 to 6.5%, an increase of 30%; the COP of the system increased from 3.2 to 4, an increase of 25%.In high temperature conditions, the temperature of water supply of heat pump steady at 20 degrees, it can meet the cooling requirements. Through the simulation analysis, it also plays a guiding role for us applying this system to actual engineering.