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System performance of HVAC in a low energy house in the cold region of Japan.

Author(s) : TAKEDA-KINDAICHI S., NAGANO K., KATSURA T., et al.

Summary

This study describes a field test on a low energy house built in the cold region of Japan. The floor area is about 200 m2. The building envelope consists of high insulated walls and windows and a floor with high heat capacity. Totally the Q-value and C-value are 0.96 W/(m2.K) and 0.4 cm2/m2 respectively. For heating and cooling, a ground source heat pump unit made in Japan is installed. Continuous heating operation indicates that the supply temperature for floor heating can be mostly kept low between 30 and 35ºC throughout the season. The daily average heating output is 3.0 kW, where higher COP can be achieved due to the partial load operation. We can also observe a high seasonal performance. The system COP including the pumping power reaches 4.45. Besides it, acceptable thermal environment is brought about at an air changing rate of 0.5 hr-1. The room temperature is kept stable above 20ºC all day. The vertical temperatures also show uniform distributions. From the monthly electric consumption, the largest consumption is showed in January due to the heating operation. The power production by the solar photovoltaic system nearly reaches the consumption in the summer season. The total amount of the annual electric consumption consists of 37% of heating, 10% of DHW and 53% of ventilation, lighting and the rest. The real consumption, that is, the difference between the production and consumption, is observed at 24 kWh/m2, which is equivalent to 236 MJ/m2 in the primary energy amount. Totally 48% of the electric power demand can be covered by the PV system.

Details

  • Original title: System performance of HVAC in a low energy house in the cold region of Japan.
  • Record ID : 2009-0863
  • Languages: English
  • Source: 9th IEA Heat Pump Conference 2008: advances and prospects in technology, applications and markets. Conference proceedings [CD-ROM + abstracts].
  • Publication date: 2008/05/20

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