Performance comparison of capillary mat radiant and floor radiant heating systems assisted by an air source heat pump in a residential building

Abstract

The radiant heating system assisted by an air source heat pump has been widely applied in China for its effective energy conservation, high comfort performance and flexible utilization. Because the coefficient of performance of the system is strictly controlled by the supply water temperature heated by the air source heat pump, an efficient radiant terminal with low-temperature supply water is of significance to the coefficient of performance. In this research, the energy-saving feature of the capillary mat radiant heating system was first proved theoretically based on the influence of the heat transfer temperature difference on the coefficient of performance of the air source heat pump. In order to compare the performances of the capillary mat radiant and floor radiant heating systems, an experiment platform of two different radiant terminals assisted by an air source heat pump was established in a residential building in Xi’an, China. Experimental results showed that, to satisfy the indoor heating requirements, the supply and return water temperatures ought to be 35.0℃ and 30.9℃, respectively, and for the capillary mat radiant heating system, 43.9℃ and 38.8℃, respectively, for the floor radiant heating system. However, the electricity consumption of the capillary mat radiant heating system is 45% less than that of the floor radiant heating system. Thus, our study validated the energy-saving potential of the capillary mat radiant heating system assisted by an air source heat pump.

Keywords

Capillary mat radiant heating Floor radiant heating Air source heat pump Coefficient of performance Energy saving

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References

. China's building energy efficiency targets: challenges or opportunities? Indoor Built Environ 2012; 21: 609–613.

. Energy demand for hot water supply for indoor environments: problems and perspectives. Indoor Built Environ 2014; 24: 5–10.

Hesaraki

Holmberg

. Demand-controlled ventilation in new residential buildings: consequences on indoor air quality and energy savings. Indoor Built Environ 2013; 24: 162–173.

Dong

Yao

Shen

Zhang

. A review of heat pump systems for heating and cooling of buildings in China in the last decade. Renew Energ 2015; 84: 30–45.

Chua

Chou

Yang

. Advances in heat pump systems: a review. Appl Energy 2010; 87: 3611–24.

Wang

Jiang

Yang

. Field test investigation of a double-stage coupled heat pumps heating system for cold regions. Int J Refrig 2005; 28: 672–679.

Shan

Yang

. Assessment of an integrated active solar and air-source heat pump water heating system operated within a passive house in a cold climate zone. Renew Energ 2016; 87: 1059–1066.

Chai

Jiang

. Experimental investigation of air-source heat pump for cold regions. Int J Refrig 2003; 26: 12–18.

Hewitt

Huang

Anderson

Quinn

. Advanced air source heat pumps for UK and European domestic buildings. Appl Therm Eng 2011; 31: 3713–3719.

10.

Tian

Ouyang

. Experimental and numerical study on aerodynamic noise of outdoor unit of room air conditioner with different grilles. Int J Refrig 2009; 32: 1112–1122.

11.

Ding

. Effect of deflecting ring on noise generated by outdoor set of a split-unit air conditioner. Int J Refrig 2006; 29: 505–513.

12.

Rhee

Kim

. A 50 year review of basic and applied research in radiant heating and cooling systems for the built environment. Build Environ 2015; 91: 166–190.

13.

Zhang

Cai

Wang

. Experimental and numerical analysis of lightweight radiant floor heating system. Energy Build 2013; 61: 260–266.

14.

Guo

Chen

Wang

Chen

. Experimental study on frost growth and dynamic performance of air source heat pump system. Appl Therm Eng 2008; 28: 2267–2278.

15.

Mikeska

Svendsen

. Study of thermal performance of capillary micro tubes integrated into the building sandwich element made of high performance concrete. Appl Therm Eng 2013; 52: 576–584.

16.

Zhao M, Gu ZL, Kang WB, Liu X, Zhang LY, Jin LW and Zhang QL. Experimental investigation and feasibility analysis on a capillary radiant heating system based on solar and air source heat pump dual heat source. Applied Energy 2016. http://dx.doi.org/10.1016/j.apenergy.2016.02.043.

17.

Chen

Jing

Shi

Fan

. Anslysis of factors influencing the COP of heat pump and energy saving methods. Fluid Machinery 2007; 35: 64–68.

18.

GB 50736-2012. Design code for heating ventilation and air conditioning of civil buildings, Beijing: The Standardization Administration of China (SAC), China Building Industry Press, 2012.