Heat pumps in existing buildings – Phase 1b. Prototype testing
The project is a research study of optimal use of heat pumps in existing buildings using wastewater as heat source. A pragmatic approach is used to solve problems, which have so far prevented using heat pumps together with wastewater. In continuation of concept study in Phase 1a, the focus is on system design, components and practical verification.
This Phase 1b project deals prototype testing of heat pumps in existing buildings using wastewater as a heat source. The work is based on the results from Phase 1a, where concept and overall design sketches were developed and described based on model calculations and measurements using an early experimental setup. Phase 1a has shown good potential, but also the need for further development of systems and components including practical operation. Legal, social and other technical issues were also studied.
Phase 1b develops and describes the different prototype designs of heat absorber, measuring performance as a function of fouling as well as maintenance needs. This is done with five wastewater wells at Havnehusene in Aarhus and by converting one well in Skovgårdsparken, which was part of Phase 1a. The project is an important base for further research on exploiting the heat from wastewater; a technology which has so far not been possible. Both projects have Brabrand Housing Association as client. The project is a prerequisite for Brabrand Housing Association to use the technology in large scale. Similarly, the housing association Ringården also in Aarhus has also shown interest.
This report is the final report on the ELFORSK project "347-029 Heat pumps in existing buildings - Phase 1b. System design, components and verification", with a project period from February 2015 to May 2019. The purpose of the project was to investigate, develop and demonstrate possible system and component designs for heat recovery from waste water in new and existing multi-storey dwellings.
"The project team estimates that there is still a great potential for recovering heat from wastewater"
The project builds on a previous ELFORSK-project entitled "345-046 Heat pumps in existing buildings - Phase 1". Here, the purpose was to develop and test a technology for recovering heat from gray and black waste water from existing residential buildings. The report from this project is available on ELFORSK's web-site and can be downloaded here: https://elforsk.dk/sites/elforsk.dk/files/me-dia/dokumenter/elforsk/Slutrapport_3.0.pdf.
In the present project, two specific buildings (Havnehusene and Skovgårdsparken), both of which belong to Brabrand Housing Association, have been used as a starting point. In the Havnehusene, a total of five spiral heat exchangers were designed, produced and installed in five associated energy wells. In Skovgårdsparken, an existing well was drilled to a further 6 m depth, in which a specially designed steel heat exchanger was immersed and installed.
Despite scant measurement results from the project's prototypes, based on this project, the project team estimates that there is still a great potential for recovering heat from wastewater. Some valuable experiences have been gained, which form the basis for the further work of developing solutions for the purpose. It is important to take into account the prerequisites and scope of application, and the concept can be extremely promising under the right circumstances. This applies, for example.
The presence of a large and stable flow of wastewater, a short distance from the heat source to the exchanger, avoids unnecessary heat loss to the ground. In addition, the concept finds its greatest justification in installations where the main supply form is natural gas and / or there is cheap solar cell power available to supply heat pump, etc.
Key figures
Category
Participants
| Partner | Subsidy | Auto financing |
|---|---|---|
| Teknologisk Institut | ||
| GEO HEAT EX ApS | ||
| Brabrand Boligforening |
