07 September 2016
Since the mid of the 1990ties low energy buildings with a significantly reduced energy consumption down to ultra-low energy standard (typical space heating energy need of 15 kWh/(m2a)) have been realised. Based on the political strategies for the building sector in terms of meeting the climate protection targets, the building concepts are currently extended to derive a nearly zero energy balance, which requires on the one hand an energy-efficient building envelope and on the other hand energy-efficient building system technologies amended by an on-site renewable energy production.
IEA HPT Annex 40 is to investigate heat pumps for the application in nearly zero energy buildings. Due to the unique features of the heat pump, the application in nearly zero energy buildings can be particularly beneficial. Besides the high performance of the heat pump in combination with adapted systems of low supply temperatures, which can be installed in buildings with high performance building envelopes due to the low space heating loads, also the integration options of heat pumps with other building technologies can be an advantage of the heat pump application in these buildings.
In the Task 3 of the IEA HPT Annex 40 technology development of heat pumps adapted to the application in nearly or net zero energy buildings have been performed. These developments are related to different aspects.
• Performance improvements of the different operation modes which can be covered by the heat pump, e.g. space heating, space cooling, domestic hot water (DHW) and dehumidification
• Multifunctional operation of heat pumps for different building services, also in simultaneous operation mode, e.g. combined space cooling and DHW production
• Integration options of the heat pump with other building system technology, e.g. solar components, which are installed in the building envelope and which could be used as heat source and heat sink.
• Design and commissioning of test houses and platforms which enable the test of nZEB technology under reproducible conditions
Due to these developments, the heat pump application in nZEB can be even better performing than in the application in normal low energy buildings. On the other hand, it can be easier to reach the nZEB balance by application of adapted heat pumps with better performance, since less energy has be generated on-site to reach the balance.
This report on Task 3 covers the technology developments performed under IEA HPT Annex 40. It is partly linked also to lab-testing and field testing of components as well as to simulation work done for the prototypes and has therefore also a connection to the field testing performed in Task 4 of the Annex and the case studies by simulations in Task 2.
The results presented in this report relate to the
• Development of integrated heat pump (IHP) variants at Oak Ridge National Laboratory (ORNL) in the USA
• Integration of heat pumps and solar components as solar assisted heat pumps at CANMET Energy of Natural Resources Canada and in Switzerland
• Development of high performance dehumidification units for air-conditioning, e.g. in office buildings in Japan
• Commission and monitoring at the net Zero Energy Residential Testing Facility (NZERTF) at the campus of the National Institute of Standards and Technologies (NIST)