Study The Heat Transfer Of Ground Heat Exchanger Based On Uncertainty Analysis

The ground source heat pump air conditioning system uses low grade greenrenewable energy from soil to heating and cooling, which has a good energy savingeffect.Conventional design of ground heat exchanger is based on deterministicfactors.But many factors influenced the process of the heat exchanger heattransfer,including the thermal properties of soil, boundary conditions and initialconditions, has significant uncertainty. which will lead to problems in designing andconstruction of ground source heat pump systems, like increasing capital cost, orinadequate heat transfer of ground heat exchangers.Therefore, this project studies ground heat exchanger heat transfer process usingMonte Carlo simulation method,which including the non-deterministic factors such assoil thermal properties, boundary conditions, buried structure. Include the following:First, stochastic analysis the factors of ground heat exchanger heat transfer’seffects,which including geotechnical media thermal properties,boundary conditions,ground structures. By analysing the sensitivity about these non-deterministic factors:soil temperature, soil thermal conductivity, thermal diffusivity soil, drilling radius, fluidflow rate, pipe diameter, pipe spacing; establishing ground heat exchanger random heattransfer model based on the existing model theory; determining statistical laws of therandom parameters, then sampling randomly from these factors. and take these samplesinto the ground heat exchanger model to make stochastic simulation calculation usingMonte Carlo simulation method.By stochastic simulation to the processes of underground pipe heat transfer, we getthe distribution about borehole radial temperature and outlet water temperature, thenstochastic analysis to simulation results.Finally, use ground source heat pump system of JiMo for calculation examples,proposed Ground source heat pump reliability design method, and compared with thetraditional design method about the length of bore.