Study on operation strategy of buried pipe heat transfer system coupled with building envelope for metro stations

This paper takes a metro station as the research object,simulates its dynamic load throughout the year,determines the parameters of the ground-source heat pump,establishes a parameter model to estimate the heat pump output and power consumption,and combines the established dynamic heat transfer model to obtain a simulation model of the ground-source heat pump system coupled with the buried pipe resistance-capacitance.Taking a 10-year operation period,the outlet water temperature and heat transfer rate of the buried pipes are calculated.The heat transfer performance under different working conditions is analysed.The operation strategy with a combination of heat pump systems and cooling towers is provided.The results show that under long-term operating conditions,the buried pipe heat transfer system coupled with the building envelope may have the conditions of unit cut-down or insufficient unit output.When the load is 80% of the calculated load,the heat pump unit output can meet the demand.The cooling tower joint operation strategy can effectively reduce the outlet temperature of the buried pipe during the cooling season,and the free cooling capacity of the cooling tower can reduce the outlet temperature of the buried pipe by 1 to 2 ℃ in the transition season,which has a good ground temperature recovery effect under long-term operating conditions.