THERMAL SCIENCE

International Scientific Journal

Thermal Science - Online First

Jianhui Niu

,

Chenyang Zhang

,

Yuzhou Wu

,

Zelong An

,

Shuxue Xu

online first only

Experimental study on air source heat pump coupled capillary floor radiant heating

ABSTRACT
In the process of global energy sustainable development, increasing the utilization of renewable energy in buildings and constructing zero-carbon buildings has become one of the important ways to alleviate global warming. In this situation, air source heat pumps are widely used because of its energy saving and stable performance. Air source heat pump coupled capillary floor radiant heating (ACFRH) uses refrigerant as a heat transfer medium to directly heat the room floor, with no pump consumption and secondary heat transfer loss. In order to better study its temperature and heating characteristics under different capillary spacing and different outdoor temperature, an ACFRH experimental device was built in the artificial environment control room. The results show that the smaller the capillary spacing, the greater the vertical temperature difference of the floor. When the outdoor ambient temperature is -5°C and the capillary spacing is 80 mm, the vertical temperature difference is 2.3°C, the surface temperature difference at different horizontal positions is 0.8°C, and 6.4°C from the compressor discharge section to the condensate outlet section. The heating capacity and heating COP of the system are maintained at about 1.99kW and 3.85, respectively.
KEYWORDS
Air source heat pump, capillary floor radiant, temperature characteristic, heating performance
PAPER SUBMITTED: 2024-11-09
PAPER REVISED: 2025-05-07
PAPER ACCEPTED: 2025-05-12
PUBLISHED ONLINE: 2025-07-05
DOI REFERENCE: https://doi.org/10.2298/TSCI241109096N
REFERENCES
  1. Ke, Z. K., et al., Energy Consumption and Carbon Emissions of Nearly Zero-Energy Buildings in Hot Summer and Cold Winter Zones of China, Sustainability, 15 (2023), 14, 11453
  2. Wang, N., et al., Performance Research and Multi-Objective Optimization of Concentrating Photovoltaic/Thermal Coupled Air Source Heat Pump Heating System, Energy, 296 (2024), 131008
  3. Cao, X. D., et al., Building Energy-Consumption Status Worldwide and the State-of-the-Art Technologies for Zero-Energy Buildings During the Past Decade, Energy and Buildings, 128 (2016), pp.198-213
  4. Song, Y. Y., et al., Using the Degree-Day Method to Analyze Central Heating Energy Consumption in Cities of Northern China, Sustainability, 16 (2024), 3, 1008
  5. Yu, Y. Z., et al., Effect of Implementing Building Energy Efficiency Labeling in China: A Case Study in Shanghai, Energy Policy, 133 (2019), 110898
  6. Zhang, S., et al., Renewable Energy Systems for Building Heating, Cooling and Electricity Production with Thermal Energy Storage, Renewable and Sustainable Energy Reviews, 165 (2022), 112560
  7. Zeng, Y. J., et al., Research on Energy Savings of an Air-Source Heat Pump Hot Water System in a College Student's Dormitory Building, Sustainability, 15 (2023), 13, 10006
  8. Chen, Q., et al., Energy, Emissions, Economic Analysis of Air-Source Heat Pump with Radiant Heating System in Hot-Summer and Cold-Winter Zone in China, Energy for Sustainable Development, 70 (2022), pp.10-22
  9. Wu, C.L., et al., Low-Temperature Air Source Heat Pump System for Heating in Severely Cold Area: Long-Term Applicability Evaluation, Building and Environment, 208 (2022), 108594
  10. Wu, C.L., et al., Optimizing the Selection and Combined Operation of Multiple Air-Source Heat Pumps for Sustainable Heating Systems, Energy and Buildings, 310 (2024), 114052
  11. Xu, S.X., et al., Experimental Investigation of an Air Source Heat Pump with Multigroup Heat Pipe Radiators, Solar Energy, 260 (2023), pp.137-146
  12. Zheng, X.J., et al., Performance of the Air Source Heat Pump Assisted Solar Heating System Combined with PCM Floor, Applied Thermal Engineering, 239 (2024), 122115
  13. Jia, J., et al., Field Test on Performance of an Air Source Heat Pump System Using Novel Gravity-Driven Radiators as Indoor Heating Terminal, Frontiers in Energy Research, 9 (2021), 765781
  14. Bai, X.X., et al., An Experimental Study on Achieving Even-Frosting for an Air Source Heat Pump Using a Novel Dual-Fan Outdoor Coil, Energy and Buildings, 255 (2022), 111695
  15. Li, H.J., et al., Experimental Study on Performance of Medium-Pressure Air-Supply Heat Pump Air Conditioning System for Pure Electric Bus, Thermal Science, 25 Part B (2021), 3, pp.2311-2318
  16. Prashantha, B.G., et al., Design and Analysis of Thermoacoustic Air Source Heat Pump Water Heaters, International Journal of Air-Conditioning and Refrigeration, 32 (2024), 1, pp.1-14
  17. Hu, B., et al., Performance Evaluation of Different Heating Terminals Used in Air Source Heat Pump System, International Journal of Refrigeration, 98 (2019), pp.274-282
  18. Ye, J.Y., et al., Experimental Study on the Heating and Humidifying Performance of Fan Coil Units with Humidification Modules in Severe Cold Regions, Energy and Buildings, 276 (2022), 112500
  19. Liu, D., et al., Comparative Analysis of Heating Characteristics of Convective-Radiant Systems Using Various Terminal Air Source Heat Pumps, Energy and Buildings, 301 (2023), 113701
  20. Hu, F.C., et al., Simulation and Analysis of Air Source Heat Pump Used in Different Heating Terminal of Beijing Rural House, Procedia Engineering, 205 (2017), pp.397-404
  21. Xu, S.X., et al., Investigation of Air-Source Heat Pump Using Heat Pipes as Heat Radiator, International Journal of Refrigeration, 90 (2018), pp.91-98
  22. Shao, S.L., et al., Thermodynamic and Economic Analysis of the Air Source Heat Pump System with Direct-Condensation Radiant Heating Panel, Energy, 225 (2021), 120195
  23. Dong, X., et al., Energy and Exergy Analysis of Solar Integrated Air Source Heat Pump for Radiant Floor Heating without Water, Energy and Buildings, 142 (2017), pp.128-138
  24. Wang, H.B., et al., Experimental and Numerical Study on Thermal Performance of a Novel Direct Expansion Air-Source Heat Pump Heating System, Frontiers in Energy Research, 9 (2022), 765221
  25. Zhao, M., et al., Performance Comparison of Capillary Mat Radiant and Floor Radiant Heating Systems Assisted by an Air Source Heat Pump in a Residential Building, Indoor and Built Environment, 26 (2017), 9, pp.1292-1304
  26. Zeng, Z.C., et al., Experimental Research and Thermodynamics Analysis of Direct Radiant Floor Heating System with Air Source Heat Pump (in Chinese), Acta Energiae Solaris Sinica, 32 (2011), 8, pp.1151-1157
  27. Cui, M.M., et al., Experimental Study on Direct Floor Radiant Heating with Air Source Heat Pump (in Chinese), Journal of Appliance Science & Technology, 4 (2022), pp.96-100
  28. Zheng, C.X., et al., Defrosting Performance Improvement of Air-Source Heat Pump Combined Refrigerant Direct-Condensation Radiant Floor Heating System with Phase Change Material, Energies, 13 (2020), 18, 4594
  29. Niu, J.H., et al., Experimental Research of Heating Characteristics on an Air Source Heat Pump System with Capillary Direct Floor Radiant, International Journal of Refrigeration, 170 (2025), pp.224-235
  30. Xu, X.S., et al.,‘Coal-to-electricity'Project is ongoing in North China, Energy, 191 (2020), 116525
  31. Shao, S.L., et al., Thermal Performance Analysis of a New Refrigerant-Heated Radiator Coupled with Air-Source Heat Pump Heating System, Applied Energy, 247 (2019), pp.78-88
  32. Dong, J.K., et al., An Experimental Study on a Novel Radiant-Convective Heating System Based on Air Source Heat Pump, Energy and Buildings, 158 (2018), 1, pp. 812-821
  33. Dang, P.F. et al., Performance Analysis of a New Type of Heat Pump System with Natural Convection Heat Sink (In Chinese), Refrigeration and Air Conditioning, 36 (2022), 2, pp.196-202
PDF VERSION [DOWNLOAD]
Experimental study on air source heat pump coupled capillary floor radiant heating