SPF Institut für SolartechnikProjektleiterin SPF
+41 58 257 41 80vera.guetle@ost.ch
Due to the necessary decarbonization of the heat supply, heat pumps are becoming increasingly important for domestic hot water preparation. However, the relatively high requirements for hot water preparation and distribution temperatures for hygiene reasons often cannot be met with current heat pump concepts without the additional use of electric immersion heaters, and the system efficiency of the heat pump and storage tank combination often falls well short of the technical possibilities in the field. This project compares different concepts for hot water preparation with heat pumps in multi-family houses. The focus is on hygiene requirements and efficiency. The aim is to develop and investigate new approaches to achieve significantly higher efficiency in apartment buildings with hot water circulation. Only natural refrigerants are to be used. The project is co-financed by the Swiss Federal Office of Energy (SFOE) and involves the Institute of Energy Systems (IES) at the OST, Lucerne University of Applied Sciences and Arts (HSLU) and various industrial partners.
The importance of hydraulic balancing of heat distribution systems for energy-efficient building operation and resident comfort has long been recognized. Nevertheless, it can be stated that there is a lack of expertise and still far too often insufficient implementations occur in practice. Companies have also noticed this gap and have developed new products or solutions. The aim of this research project is to investigate how well and reliably these solutions for automatic hydraulic balancing work, and what benefits they provide in terms of comfort and energy efficiency. For this purpose, the products will be installed in real systems and tested by means of a hardware-in-the-loop procedure. The effects on a virtual building modeled in detail can be tracked and evaluated in real time. The results are presented to the professional community in the form of factsheets that enable an independent comparison.
Introduced in 2002, the "SPF Solar Glass Certificate" has become a widely used tool for quality assurance in the solar thermal industry worldwide and was extended to solar glass for PV modules in 2012. As part of the certification, the influence of transmission, its change due to solarization and the incidence angle modifier (IAM) on the performance of the end product (i.e. solar thermal collector, PV module) is condensed into a single factor. However, the certification process for glass for PV modules is relatively complex and therefore time-consuming and cost-intensive. In addition, colored glass cannot always be evaluated correctly. The demand for colored PV modules, especially for building integrated photovoltaics, is constantly increasing. The aim of the CoSoG4PV project, is to extend the certification process to colored solar glass and to simplify the certification process. Therefore, a new measurement device is being developed at SPF and the methodology for the SPF Solarglass PV certificate is being adapted.
Thermal stratification is an important parameter in the energy evaluation of storage tanks. The electrical energy consumption in a heat pump system can be up to 40 % lower with a well stratified storage tank than with a poorly stratified thermal energy storage.
In the StorEx project, SPF introduced stratification efficiency as a key performance indicator and at the same time a method for measuring it, which has already become established in Switzerland.
An alternative to this is the measurement of the storage tank according to the EN 12977-3 standard with a subsequent simulation with a calibrated model.
In order for the «thermal stratification» to become a generally, or internationally, recognized characteristic value for thermal storage tanks with a clearly defined measurement procedure, it is important that these two procedures are investigated in a comparative measurement. This is the aim of this project.
In the project HpCosy the basics for a decentralized brine-water heat pump system for flats in
multi-family houses will be developed and investigated. This "Comfort System" includes the functions heating, cooling and domestic hot water preparation, whereby the latter can optionally be controlled with the consideration of availability of own photovoltaic electricity as an individual system or in a swarm (cooperation for self-consumption).
The project is being carried out on behalf of the Swiss Federal Office of Energy and in collaboration with other partners from industry and research.
