Theoretical model and experimental validation of a direct-expansion solar assisted heat pump for domestic hot water applications Articles uri icon

published in

publication date

  • September 2012

start page

  • 704

end page

  • 715


  • 1


  • 45

International Standard Serial Number (ISSN)

  • 0360-5442

Electronic International Standard Serial Number (EISSN)

  • 1873-6785


  • This paper has shown the development of a theoretical model to determine the operating parameters and consumption of a domestic hot water (DHW) installation, which uses a direct-expansion solar assisted heat pump (DXSAHP) with refrigerant R-134a, a compressor with a rated capacity of 1.1 kW and collectors with a total area of 5.6 m(2). The model results have been compared and validated the experimental results obtained with the equipment installed at the University Carlos III, South of Madrid. The analysis was conducted over the course of a year, and the results have been represented depending on the meteorological and process variables of several representative days. Taking into account the thermal losses of the installation and the dependency on the operating conditions, the acquired experimental coefficient of performance is between 1.7 and 2.9, while the DHW tank temperature over the course of the study is 51 degrees C.


  • solar collector; heat pump; direct expansion; water heater; efficiencies