Research and development of the hybrid ground-coupled heat pump technology in China

The hybrid ground-coupled heat pump (HGCHP) systems with supplemental heat rejecter/supplier can effectively solve heat imbalance problems in the subsurface, and consequently improve the operation performance of the geothermal systems. For example, solar energy and/or industrial waste heat may be used as stable heat sources for underground heat storage in northern China with higher heating load, and cooling towers are installed to release heat into the air in southern China, where more cooling demand is needed. This paper reviews and discusses different HGCHP systems, which have been applied in China. And based on the heat transfer model of vertical borehole heat exchangers (BHE) for HGCHP systems, physical and mathematical models of multistage series circuits are developed to illustrate the heat transfer process of the underground thermal storage. A set of parameters, such as borehole spacing, heat recharging rate fractions and thermal properties of soils, which affect the thermal performance of the ground heat exchangers are analyzed, and the optimal solutions are discussed for engineering application.

[1]  Alvin C.K. Lai,et al.  Full-scale temperature response function (G-function) for heat transfer by borehole ground heat exchangers (GHEs) from sub-hour to decades , 2014 .

[2]  Alan S. Fung,et al.  Performance prediction of a hybrid solar ground-source heat pump system , 2012 .

[3]  Yan Gao,et al.  Thermal performance and operation strategy optimization for a practical hybrid ground-source heat-pump system , 2014 .

[4]  Hongxing Yang,et al.  Feasibility study on novel hybrid ground coupled heat pump system with nocturnal cooling radiator for cooling load dominated buildings , 2011 .

[5]  Alvin C.K. Lai,et al.  Analytical model for short-time responses of ground heat exchangers with U-shaped tubes: Model development and validation , 2013 .

[6]  Yang Hongxing,et al.  Study on hybrid ground-coupled heat pump systems , 2008 .

[7]  Pingfang Hu,et al.  Study on intermittent operation strategies of a hybrid ground-source heat pump system with double-cooling towers for hotel buildings , 2014 .

[8]  Z. Fang,et al.  Heat transfer analysis of boreholes in vertical ground heat exchangers , 2003 .

[9]  Min Li,et al.  Short-time performance of composite-medium line-source model for predicting responses of ground heat exchangers with single U-shaped tube , 2014 .

[10]  Alvin C.K. Lai,et al.  New temperature response functions (G functions) for pile and borehole ground heat exchangers based on composite-medium line-source theory , 2012 .

[11]  Hua Dong,et al.  Numerical simulation of the performance of a solar-earth source heat pump system , 2006 .

[12]  Shengwei Wang,et al.  Performance analysis of hybrid ground source heat pump systems based on ANN predictive control , 2014 .

[13]  A. Lai,et al.  Thermodynamic optimization of ground heat exchangers with single U-tube by entropy generation minimization method , 2013 .

[14]  Alvin C.K. Lai,et al.  Analytical solution to heat conduction in finite hollow composite cylinders with a general boundary condition , 2013 .

[15]  Jinggang Wang,et al.  Study on hybrid ground-coupled heat pump system for air-conditioning in hot-weather areas like Hong Kong , 2010 .

[16]  F. Wang,et al.  Numerical simulation of solar assisted ground-source heat pump heating system with latent heat energy storage in severely cold area , 2008 .

[17]  Jeffrey D. Spitler,et al.  Simulation of hybrid ground-coupled heat pump with domestic hot water heating systems using HVACSIM+ , 2008 .

[18]  Wenxing Shi,et al.  A potential solution for thermal imbalance of ground source heat pump systems in cold regions: Ground source absorption heat pump , 2013 .

[19]  Ming Dong,et al.  Experimental performance analysis of a solar assisted ground source heat pump system under different heating operation modes , 2015 .

[20]  Z. Fang,et al.  A finite line‐source model for boreholes in geothermal heat exchangers , 2002 .