Study on Feasibility of Accumulating Solar Energy into Soil for Improving the Imbalance of Heat Injection and Extraction in GHP System

  • Kai Liu
  • Nan Wang
  • Wanlong Cai
  • Xinke WangEmail author
  • Fenghao Wang
  • Bo Xiao
Conference paper
Part of the Environmental Science and Engineering book series (ESE)


Geothermal heat pump system (GHP) is efficient to utilize renewable energy in cooling and heating of building. However, the major problem is that the coefficient of performance (COP) of GHPs will decay after a long-time operation because of the imbalanced energy injection into and extraction from the ground. It is an effective way to apply solar collectors in the GHPs to collect thermal energy in the non-heating season and deliver the heat into ground, which may relief the imbalance. In our research, a demo project of solar-assisted geothermal heat pump system (SAGHP) in a rural building in Xi’an was built up, which delivers hot water from solar collector into soil from September 1 to November 14, 2018. For analyzing the effectiveness of elevating the ground temperature, a TRNSYS model was established, verified by the measured data in the project, and served for simulating three systems, which including the SAGHPs without accumulating solar energy in soil, the SAGHPs with accumulating thermal energy in soil in summer, and the SAGHPs with accumulating thermal energy in soil in autumn. The comparison of systems showed the significance of thermal storage in Xi’an and the feasibility of thermal injection in autumn for solar collection for improving the heat imbalance of GHPs.


Ground source heat pump Solar energy Soil thermal storage The rural buildings TRNSYS 



This project was financially supported by China Construction Science & Technology Group Co., Ltd. (Grant No. CSCEC-2016-Z-6).


  1. 1.
    Ozgener, O., Hepbasli, A.: A review on the energy and exergy analysis of solar assisted heat pump systems. Renew. Sustain. Energy Rev. 11(3), 482–496 (2007)CrossRefGoogle Scholar
  2. 2.
    Cai, W., Wang, F., Liu, J., et al.: Experimental and numerical investigation of heat transfer performance and sustainability of deep borehole heat exchangers coupled with ground source heat pump systems. Appl. Therm. Eng. 149, 975–986 (2019)CrossRefGoogle Scholar
  3. 3.
    Verma, V., Murugesan, K.: Experimental study of solar energy storage and space heating using solar assisted ground source heat pump system for Indian climatic conditions. Energy Build. 139, 569–577 (2017)CrossRefGoogle Scholar
  4. 4.
    Yin, L.: Simulation study on TRNSYS based solar-earth source heat pump system. Taiyuan University of Technology, Taiyuan, China (2013)Google Scholar
  5. 5.
    Liu, L., Zhu, N., Zhao, J.: Thermal equilibrium research of solar seasonal storage system coupling with ground-source heat pump. Energy 99, 83–90 (2016)CrossRefGoogle Scholar
  6. 6.
    Wang, F., Liu, Z., Li, Z.: Performance analysis of seasonal soil heat storage air conditioning system in solar ground coupled heat pump. In: International Conference on Electronic and Mechanical Engineering and Information Technology 2011, EMEIT, Harbin, Heilongjiang, China, IEEE, 12–14 Aug 2011Google Scholar
  7. 7.
    Ucar, A., Inalli, M.: Thermal and economic comparisons of solar heating systems with seasonal storage used in building heating. Renew. Energy 33(12), 2532–2539 (2008)CrossRefGoogle Scholar
  8. 8.
    Tong, C., Li, X., Duanmu, L.: Research on heat transfer characteristics of soil thermal storage in the non-heating season. Procedia Eng. 205, 3293–3300 (2017)CrossRefGoogle Scholar

Copyright information

© Springer Nature Singapore Pte Ltd. 2020

Authors and Affiliations

  1. 1.China Northwest Architecture Design and Research Institute Co. LTD.Xi’anChina
  2. 2.School of Human Settlements and Civil EngineeringXi’an Jiaotong UniversityXi’anChina
  3. 3.Xi’an Meteorological AdministrationXi’anChina

Personalised recommendations