| Ground-source VRV air conditioning system is a kind of air conditioning system which uses renewable energy. The system is usually studied for its performance in office buildings at present instead of residential districts, whose utilization rate is very low; Some researches of the factors affecting its performance have been gained, while how to realize the optimal operation of ground-source VRV air conditioning system and propose the control strategy of the water loop are rarely studied. Therefore, the performance simulation and optimizing operation of ground-source VRV air conditioning system in residential district were conducted in this paper. The main contents and results of the research are as follows:Firstly, the model of target residential construction in Nanjing is established with the help of DeST software, the dynamic hot and cold load all the year round is simulated and the operating energy consumption is calculated. Then its superiority to split type air conditioner in energy saving is obtained.Secondly, the soil heat balance of ground-source VRV air conditioning system is analyzed. An automatic switching operation scheme between cooling tower and buried pipe is proposed by studying the factors affecting cooling tower and host performance. The project keeps the system running effectively and solves the problem of annual soil thermal imbalance.Thirdly, a research on the performance of the host and frequency conversion of the water pump is conducted and SIMULINK module is used to establish the model of ground-source VRV air conditioning system. The COP of host and the energy consumption of pump in condition of several different control modes of water temperature in and out of host are simulated in summer and winter respectively. So is the COP of the air conditioning system.Lastly, some conclusions are obtained as follows after analyzing. The optimal pump frequency conversion control strategy under the operation condition of buried pipe in summer is temperature difference of water in and out of host set as 5 ℃ with total load rate of system below 50% and 4.5 ℃ with total load rate more than 50% with two water pumps. While in winter, it is 4 ℃ of temperature difference of water in and out of host with one variable frequency pump. What’s more, the control strategy of water pump in the running cooling tower system and the adjustment strategy of electric valve of host are proposed in this study, providing guidance for optimizing operation of ground-source VRV air conditioning system of residential area in our country. |
