Research On Long-time Operational Performance Of Heating For Ground Coupled Heat Pump System In Severe Cold Area

The ground source heat pump is one of green air-conditioning technology， whichcan solve the shortage of energy and realize the sustainable development of our countyin21st century. With the improvement of awareness of energy conservation，peoplehave paid a lot of attention to the energy saving and environmental protection featuresof this technology. But in the severe cold regions，the long-time application of groundcoupled heat pump will cause the temperature decrease of the surrounding soil，becausethe load difference between summer and winter seasons，and the low temperature of soilwill influence the long-time operation of heat pump. Based on the previous research，this paper will discuss the long-time operational performance of heat pump heatingsystem.In order to study the long-term operational characteristics of ground coupled heatpump system. In this paper，the TRNSYS software has carried on the long-termnumerical simulation for the heat pump system。First of all，I selected a certain officebuilding in Harbin region，and then，designed the ground coupled heat pump system，which including the buried pipe heat exchanger system、interior radiant floor andheating system equipment selection, etc. For the sake of the system is running good，Ichose the optimal design parameters based on the previous research in the process ofdesign，such as: the hole diameter、borehole spacing and tube flow velocity，etc. Finally，I used the TRNSYS software to establish the whole soil source heat pump system，andset the reasonable parameters for models in simulation according to the designedparameters.This paper includes two kinds of projects：the ground coupled heat system has a setof buried tube heat exchanger，which take heat from a piece of the soil annually；Another system has two sets of the underground buried pipe system，which take heatfrom the two pieces of soil alternatively in years. According to simulation data resultsand graphs，I analyzed the operational parameters of the two systems respectively，which includes how the temperature of soil changes respectively in a cycle and long-time period、the temperature change of heat transfer medium exported buried tubeheat exchanger、COP of heat pump，etc. And，I got the maximum cycle of normaloperation about the two systems.Finally，I also worked up a rough calculation for theeconomics of heat pump systems，and studied the influence of lower soil temperature onthe long-term operational economics of the systems.This paper provides some theoretical basis for the application of ground coupledheat pump system in severe cold regions. what is more，it lays foundation for the furtherresearch and the optimization of operating performance. to a certain extent, the resultscan be reference of practical engineering application.