Modeling and application of direct-expansion solar-assisted heat pump for water heating in subtropical Hong Kong

Direct hot water production consumes about 4% of the total energy use in Hong Kong, and about 20% when considering only the domestic sector. For water heating the energy sources are mostly town gas, liquefied petroleum gas and electricity. The use of heat pump or solar water heating, particularly the solar-assisted heat pump options, is not popular. In this paper, the potential application of a unitary type direct-expansion solar-assisted heat pump (DX-SAHP) system was examined. A numerical model of the DX-SAHP system was first introduced. From the simulation results with the use of the Typical Meteorological Year (TMY) weather data of Hong Kong, the system was found achieving a year-average coefficient of performance (COP) of 6.46, which is much better than the conventional heat pump system performance. The potential use of DX-SAHP therefore deserves further evaluation.

[1]  P. Ineichen,et al.  A new simplified version of the perez diffuse irradiance model for tilted surfaces , 1987 .

[2]  Bin-Juine Huang,et al.  Performance characteristics of integral type solar-assisted heat pump , 2001 .

[3]  M. Chandrashekar,et al.  A comparative study of solar assisted heat pump systems for canadian locations , 1982 .

[4]  L. W. Crow.  Weather year for energy calculations , 1984 .

[5]  Tin-Tai Chow,et al.  Performance analysis of a photovoltaic heat pump , 2008 .

[6]  Abdullah Akbulut,et al.  Performance characteristics and energy-exergy analysis of solar-assisted heat pump system , 2008 .

[7]  Ruzhu Wang,et al.  Experimental performance analysis and optimization of a direct expansion solar-assisted heat pump water heater , 2007 .

[8]  John Z. Lin,et al.  Generation of a typical meteorological year for Hong Kong , 2006 .

[9]  Ruzhu Wang,et al.  Study on a direct‐expansion solar‐assisted heat pump water heating system , 2003 .

[10]  S. Ito,et al.  PERFORMANCE OF A HEAT PUMP USING DIRECT EXPANSION SOLAR COLLECTORS 1 Paper presented at the ISES Sol , 1999 .

[11]  T. Freeman,et al.  Performance of combined solar-heat pump systems , 1979 .

[12]  Tin-Tai Chow,et al.  Numerical study of desirable solar-collector orientations for the coastal region of South China , 2004 .

[13]  R. Reid,et al.  The Properties of Gases and Liquids , 1977 .

[14]  Ruzhu Wang,et al.  Performance of a multi-functional direct-expansion solar assisted heat pump system , 2006 .

[15]  Bin-Juine Huang,et al.  Heat-pipe enhanced solar-assisted heat pump water heater , 2005 .

[16]  D. Jung,et al.  Capillary tube selection for HCFC22 alternatives , 1999 .

[17]  Hongxing Yang,et al.  Potential application of solar thermal systems for hot water production in Hong Kong , 2009 .