Prototypes developments

Download Annex 49 Report part 4 – Heat pump prototype developments and testing for nZEB application

 
Prototype developments of heat pumps for nZEB
Besides the monitoring of marketable heat pumps treated in the Annex 49 report part 2, also prototype heat pumps for the application in nearly Zero Energy Buildings have been developed and tested in Annex 49, which are treated in this report.
Thereby, the developments were dedicated to highly integrated heat pumps developments, on the one hand regarding the functionality of the heat pump, i.e. multiple building integrated services in one packaged unit, and on the other hand regarding compactness of the compo-nents/unit. Moreover, the integration of cooling function has been a focus of the deve¬loped prototypes:
At IWT of TU Graz, a façade integrated cooling device with 2 kW cooling capacity has been developed by simulations, proto¬typing and monitoring in two test cells of the campus of Graz Technical University. The prototype heat pump is covered by façade integrated PV-modules, which are sufficient to supply the module during summer cooling operation due to good load match. The unit can cover about 40% of the space heating demand of the adjacent room for Graz climate data. Different operation modes like grid independent and grid coupled operation, with and without battery storage as well as different cooling options by fan coils or cooling ceiling have been investigated. Further developments encompass facace integration of larger units.
At the IET of OST Eastern Switzerland University of Applied Sciences, an unglazed absorber component has been tested for night time cooling application. The components is already market available for space heating and DHW application, and the objective is to integrated free cooling function in the system configuration. Cooling capacities, though, are strongly depending on the weather conditions. At clear sky and moderate nighttime temperatures between 23-13 °C, cooling capacities up to 250 W/m2 have been measured, while for cloudy sky values are in the range of 100 W/m2 were measured.
At the CEEE of the University of Maryland, a roving comforter (RoCo) unit, which is a personal-sized heat pump that cools indoor air to guarantee occupants comfort has been developed as several prototypes and is now in the market introduction. Energy analysis in office buildings for 9 climates revealed that RoCo can provide up to 49% energy savings in mild climate, such as San Francisco, CA, and 9% energy savings in hot climate, such as Phoenix, AZ. PCM development is another focus of the project, both regarding good latent heat capacity and thermal conductivity as well as regarding lowering costs and VCC integration. Field testing showed that RoCo can provide 10 W effective cooling, reducing body temperature by 1 K and heart rate by 9 BPM. Most people expressed a better thermal sensation with RoCo.
At the ORNL a long-term development of the Integrated Heat Pump (IHP) for the space heating and cooling as well as DHW and dehumidification function has been carried out. A ground-source and three air-source variants have been designed, lab tested and simulated and subsequently field testing. Field tests results for the different prototypes variant are summarised with implications to market state and introduction. While the ground-source variant is already on the market for several years, for the gas-driven air-source variant, a value engineering is carried out in order to improve cost-competitiveness.
At NIST campus the Net Zero Energy Residential Testing Facility (NZERTF) has been designed and operated for several years. The test house with tunable loads is a dedicated testing platform for nZE technologies. As contribution to the Annex 49 two air source heat pumps, a conventional ducted system and a small duct high velocity system has been extensively testing in space heating and cooling mode. Further testing incorporate among other also the ground-source IHP variant.