| With the improvement of people’s living standards and rapid economic development,people’s demand for indoor comfort is getting higher and higher,air conditioning is a necessary means to ensure indoor comfort.Therefore,reducing the energy consumption of air conditioning systems is an urgent issue for achieving carbon neutrality as soon as possible.A liquid dehumidification air conditioning system with compound direct evaporative cooling of chilled water are proposed in this paper,which decreases the demand for high-grade energy and reduces energy waste,so conducts related research on this.First,the structural form and working principle of the fresh air system are determined and the analytical models of each equipment are established.The accuracy of the main equipment models is verified through experimental and numerical solutions to provide for further construction of the complete air conditioning system.Secondly,an office building with a fresh air volume of 12.09 kg/s in Nanchang City is used as an example to analyze and simulate the main equipment in its fresh air system,and to study the influence of NTU and fluid parameters on the performance of the equipment themselves.The results show that the heat and mass transfer capacity slowly tends to the limit after increasing the NTU of dehumidifier/regenerator,evaporator and cooling tower to 4,3.5 and 2,respectively;The heat and mass transfer capacity is close to optimal for the dehumidifier solution flow rate,cooling tower and evaporator cold water flow rates of 7 kg/s,5 kg/s and 6 kg/s,respectively.Again,the effects of NTU and fluid parameters of each device on the performance of the fresh air system are studied.Under the condition of meeting the indoor temperature and humidity,the energy efficiency ratio and the exergic efficiency of the fresh air system can reach 0.72 and 0.41 respectively;The amount of variation in the performance evaluation indexes of each system is not significant when the NTU of each unit other than the surface cooler is increased to 3;When the total solution flow rate of the dehumidifier is the base working condition,the solution flow rate ratio of the two dehumidifiers reaches 1,the supply air temperature and humidity just meet the requirements;The total solution flow rate in the dehumidifier and air flow rate in the evaporator at 14 kg/s and 6.64 kg/s,respectively,result in the optimum energy efficiency ratio and the exergic efficiency.Finally,the load model of this office building is built and solved using TRNSYS,where the maximum cooling load is 496.29 k W and the cooling load index is 95.44W/m~2.The initial selection of this air conditioning system is based on the load,so that a complete air conditioning system can be built to simulate its energy consumption and energy saving.The results show that when the air conditioning fresh air system uses solar regenerative heat source for hot water supply,the total hot water energy consumption in July and August is 4.34×10~5 k Wh,the total heat handled by the fresh air is 2.65×10~5 k Wh,and the total cooling power consumption is 6.16×10~4 k Wh.Compared to conventional air conditioning systems,the energy saving rate reaches55.75%.The research in this paper demonstrates the feasibility and energy efficiency of the proposed solution dehumidification air conditioning system with composite direct evaporative cooling chilled water,and the system performance and energy consumption study can provide reference for the practical application of the system. |
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