Experimental And Modeling Analysis Of The Ground Heat Exchanger Direct Cooling Of Office Buildings In Hot Summer And Cold Winter Areas

It is an effective way to utilize natural cold energy by Combining the capillary net work radiation system with soil energy storage technology.In this paper,an experimental system that is made up of the ground source heat pump&capillary radiant ceiling and can cool the room down without refrigeration units in Wuhan.Through the ground heat exchanger direct cooling system experiment in summer,we obtained the operational characteristics of the ground heat exchanger direct cooling system,which is used in office buildings in hot summer and cold winter areas.As the experimental results show,the ground heat exchanger direct cooling system can provide a maximum cooling capacity of0.55 kW for an area of 35m~2 laboratory in the hot summer and cold winter area,under the condition that the indoor temperature is lower than 27°C.This period of time is mainly distributed in the initial and final stages of the cooling season,and during that time the capillary seat cooling capacity can reach 25W/m~2.Based on the previous experimental data,this paper establishes a simulation model of the ground heat exchanger direct cooling system to research the operating characteristics of the ground heat exchanger direct cooling system in the cold season in Wuhan office buildings.Comparing of room temperature simulation results in summer when no cooling measures were taken in the room,using the ground heat exchanger direct cooling technology can reduce the indoor average temperature by 6.9 and the indoor peak temperature by 9.7°C.The author applies the simulation model to the office buildings of 6typical cities in the middle and lower reaches of the Yangtze river.It is found that the cooling season of typical cities in the middle and lower reaches of the Yangtze river in summer is more than 4 months and the time that the indoor temperature below 27°C is 43to 52 days when we only run the ground heat exchanger direct cooling system.This paper briefly analyzes the common control strategies of central air conditioning systems and use the simplified model predictive control(MPC)method to optimize the experimental room control system.This paper establishes a TRNSYS simulation model of massive office building cooling tower+chiller cooling system,the ground source heat pump+radiant ceiling cooling system and the ground heat exchanger direct cooling system.We obtain the energy consumption data in the building cooling period under the typical annual meteorological conditions in Wuhan.In the initial and final stages of the cooling season,The average COP of the system can reach 4.17 throughout the cooling season,when adopt the ground heat exchanger direct cooling system.Comparing with only the ground source heat pump unit as a cold source,it can save 22%energy.Comparing with the central air-conditioning system that Using a conventional water-cooled unit as a cold source and a fan coil as the end,it can save 34%energy.