Application Study Of Air Conditioning System Based On Heat Pipe In Nearly Zero-energy Building

Low energy building and even nearly zero-energy building are the future direction of architectural research and development,reducing energy consumption of air conditioning system is one of the key.For this problem,combined with the actual nearly zero-energy demonstration project,a highly efficient energy-saving air conditioning system is proposed,which comprehensively utilizes solar and geothermal energy,changes the temperature in the room through the radiation terminal,and uses underground heat pipe auxiliary energy supply.Combined with the PMV-PPD evaluation index,the comfort of indoor conditions is studied.The results show that the indoor design temperature can be increased to 28℃in summer or reduced to 18℃in winter,which is still able to meet the requirements of human comfort.Using FLUENT simulation software,the feasibility of the direct heating of the heat pipe on the ground side of the air conditioning system is studied,and the operation effects of the inorganic heat transfer element,the traditional heat pipe and the ordinary metal rod are analyzed and compared.The results show that the three schemes increase the indoor temperature by 12℃,8℃,1℃,and the inorganic heat transfer element and the traditional heat pipe have good effect.Using eQUEST simulation software and pinch technology,the energy consumption and the heat exchanger network optimization of the air conditioning system applied to the nearly zero-energy demonstration project are studied.The results show that the annual heating capacity of the whole building is 13.41kWh/(m~2·a),the annual cooling capacity is 14.10kWh/(m~2·a),which meets the energy consumption control index;the air-conditioned room’s temperature meets the requirements throughout the year;in the energy system,the proportion of renewable energy is between 80%and 90%,and the proportion of electricity is only between 20%and 10%;the heat exchange network needs external addition of 11.42k W heat under the winter conditions;the temperature difference between the hot and cold logistics’Temperature-Enthalpy line is higher than that of pinch point and the heat transfer network needs to be optimized.The results show that the application of the air conditioning system in the nearly zero-energy building is feasible.This paper can provide some guidance for energy saving design of air conditioning system in the nearly zero-energy building.