EXCESS Result Update: PVT as key technology for Positive Energy Buildings

12 February 2024

EXCESS Result Update: PVT as key technology for Positive Energy Buildings

The EXCESS project is in its final year, and with it, constructions and refurbishments at our four demo sites are not only progressing, but results keep trickling in from their real-life use and testing.

Amongst which is the application of the Dual Sun Photovoltaic Thermal (PVT) hybrid solar collector, which combines photovoltaic (PV) and solar thermal technologies into a single system.  Thereby the PVT is offering the potential for simultaneous electricity and heat generation.

The PVTs have been implemented across different EXCESS demo sites. First results show that the technology is particularly useful in case of limited roof spaces on the houses. In principle promising applications are PVT for Domestic Hot Water (DHW) production, PVT for coupling with groundsource heat pumps and PVT as single source for water to water heatpumps. Also, the system cools the  the panel and thereby increases the efficiency of the PV panel by more than 10%. The coupling with groundsource heatpumps is tested in two EXCESS demos, in the Belgian demo in Hasselt and the Finish demo building in Kalasatama Finland.

In the Finnish demo a combined system of PVT and geothermal heatpump with 600m deep boreholes and 79kWp PVT acts as seasonal storage that stores the heat energy from the sun in summer to increase the efficiency in winter. The system is part of a 8 floor multistorey building. In the Belgian demo, a cluster of buildings being owned by a social housing company, has shown that
PVT, while being more expensive than PV, can reduce the depth of drillings, which brings economic savings making PVT a relevant alternative.

Overall, the findings show that the application and replication potential depends on several factors among others on the climate zone. The highest replication potential for PVT can currently be assumed to be in the Nordics, where heating demand is high and  ground source heatpumps are already commonly available. PVT acts as an additional heat source or can be useful if the collector is undersized e.g. when building usage is changing or if too less space for drilling is available. In central Europe PVT has a high potential to be used for DHW, or combined with a groundsource heatpump but is competing with airsource heatpumps. In the case of the Belgian demo, a centralized groundsource heatpump however was the preferred solution compared to individual airsource heatpumps. In Southern Europe finally applications with a high replication potential for PVT are using this technology for DHW or for heating swimming pools.

Both, in the Finnish and Belgian demos, the testing and monitoring has started and the resulting data will provide additional insights on the efficiency of the systems in the coming weeks.

If you are interested to find out more about EXCESS solutions for the demo sites, their testing and other results, please contact us under info@positive-energy-buildings.eu or click here for more.

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