National Austrian Networking Workshop in the frame of the IEA HPT Annex 49 held at AIT in Vienna

On Thursday, January 16, a 4-hour networking workshop organised by the Austrian national team in IEA HPT Annex 49 was held at the Austria Institute of Technology (AIT), Vienna. The Workshop was attended by about 25 stakeholders from the Austrian heating industry. The objective of the workshop was to present national results of the Austrian Annex 49 contribution and discuss the results with the attendees.

C. Köflinger (AIT) and F. Ochs (UIBK) gave a welcome to all the attendees, introducing AIT and the programme of the workshop and the Austrian FFG project in IEA HPT Annex 49. Austrian participants are UIBK, TU Graz and AIT.

Then, as introduction, C. Wemhoener presented an outline of the international IEA HPT Annex 49 collaboration, mentioning the different implementations of nZEB in the EU member states. Interim results on a methodology to compare ambition levels of the different implementation was outlined. Moreover, C. Wemhoener presents project examples for the integration of heat pumps in a low-temperature grid in Germany and monitoring results of an nZEB in Switzerland.

F. Ochs of UIBK and A. Heinz of TU Graz followed with an analysis of the national implementation of nZEB in Austria for residential and office buildings. There are two pathways to fulfil the requirements in Austria, and different system technology solutions are possible. As conclusion, for both the residential and the office buildings, the requirements are relatively easy to fulfil, so the ambitious targets for nZEB envisaged in the EU EPBD-Directive are not adequately addressed. Consequently, the Austrian requirements are recommended to be tightened.

R. Hammerling of Wien Energie collaborates with the AIT in the integration of heat pumps with the multiple heat sources for a new-built neighbourhood Aspern. The heat source comprise ground water, ground, heat recovery from garage air and solar thermal and solar PV/T collectors . Experience from monitoring shows that in detail many problems occur in the connection of the systems, but as conclusion, there are also benefits by integrating the different heat sources in terms of regeneration of heat sources and favourable operation conditions.

P. Horn of AIT presented conclusion of a case study for non-residential nZEB, which have been modeled in order to facilitate the commissioning phase. Even though the modelling of the system is a high initial expenditure, the controller settings and strategies can be tested beforehand with the model. This is a big benefit for the commissioning and helps to analyse malfunctions of the system afterwards.

Furthermore, a monitoring project and a prototype heat pump development are part of the Austrian contribution to IEA HPT Annex 49.
F. Ochs showed results of the heat pump integration and optimisation in two nZEB multi-family passive buildings where a three-year monitoring and accompanying modelling and simulations are carried out. The project proves a successive improvement of the heat pump system by the simulation studies based on the monitoring data, but reaching the nZEB balance in larger residential buildings can be challenging. Thus, a high-performance building envelope and a good system performance are prerequisites to reach the NZE balance.
A. Heinz gave insight in a prototype development of a façade-integrated heat pump at TU Graz. Monitoring took place in two test cells on the university campus. Accompanying simulations confirm, that the system is suited for covering the space cooling demand at good comfort conditions for the adjacent room, but for Graz climate, the space heating cannot be entirely covered due to capacity limitations of the prototype. Nevertheless, the development is promising and shall be further investigated.
As concluding presentation C. Wemhoener presented different aspects on the design and performance of speed-controlled air-to-water heat pumps which have been investigated by simulations as Swiss contribution. Both in space heating and DHW operation performance increase is possible with speed-control, but simulations also confirm that existing design rules can still be applied for speed-controlled heat pumps. Also, aspects of energy flexibility have been investigated, which may reduce the cost depending on the market conditions, but may at the same time increase the energy consumption.
The workshop was accompanied by a lab visit of the heat pump testing labs at AIT and after the workshop the discussion was continued in a get-together event with hot sausage and cold beer, provided by simultaneous heat pump operation.

Presentations of the workshop can be downloaded under publications