Fraunhofer ISE

  das Haus

definitions and explanations

  Building


  heated area:  196 m²

  space heating demand: ca. 100 kWh/m²a

  number in household:  3-4


  Heating System


  thermal power:  11 kW

  heat source:  outside air and exhaust air

  heat distribution:  floor heating


  Evaluation

  

The heat source for the system is outside air. For DHW a second heat pump using exhaust air as heat source is installed. The heating circuit contains a buffer storage. The system uses a separate heat pump for DHW where a DHW storage is integrated additionally. The usage of exhaust air as heat source for DHW creates good preconditions for the heat pump's efficiency as the exhaust air 's temperature is usually higher than the outside air. In addition, underfloor heating further contributes to good efficiency values as this distribution system can be operated with relatively low inlet tempertures.   

In 2010, efficiency amounted to 3.4 and was significantly higher compared to the average of 2.9. The good value results from low inlet temperatures in the heating circuit and the exhaust air's temperature for the second heat pump. Both back-up heaters have a share of 1 % of the total electrical energy demand which is below the average of 4 % and as a consequence positively influences efficiency. The share of DHW in 2010 amounted to 6 % and thus was far below the average of 19 % which also had a positive effect on efficiency.

anlagenschema Click on the picture to see current data

energy balances and seasonal performance factors SPF:

2008

2009

2010

2011

2012

2013

2014

2015

gelb compressor & controller (HP1 & HP2) grau fan (HP1 & HP2)
schwarz Back-up heaters (HP1 & HP2) rot space heating blau DHW gruen SPF
strom average energie average AZ average
Click on the chart to see the average monthly data

Average daily temperatures:

anlagenschema anlagenschema anlagenschema Outside air                           Heating circuit                DHW circuit



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