For this project, The Technical University of Denmark (DTU) has analyzed a number of solar heating systems, examining the energy savings that can be obtained from different systems, houses and energy systems. The project shows that annual energy savings for new solar heating systems in detached houses are high, between 300 and 2090 kWh per m2 solar collector.
Project description
In the summer 2007 the project Energy savings for solar heating systems" was started. Solar collector manufacturers were invited to install "state of the art" solar heating systems for one family houses in Department of Civil Engineering's test facility for solar heating systems. Velux A/S and Batec A/S installed solar domestic hot water systems and Thermo-Sol installed a solar combi system in the test facility. In the test facility measurements of the thermal performance of the systems are carried out and simulation models used to calculate the yearly thermal performance of the systems, are validated by means of the measurements. Calculations of the yearly thermal performance of the systems will be carried out with the validated models, and a number of calculations with different designs of the systems will be carried out in order to inspire the manufacturers in their efforts to improve their systems. Information meetings will be organized open for all interested. Information on solar heating systems, on the project and on energy savings for solar heating systems will be given. The three manufacturers will participate in the meetings and the tested systems will be shown. In this way interested home owners will get in contact with manufacturers and researchers. In this project Energy savings for solar heating systems, phase 2, a number of solar solar heating systems with different designs and sizes will be installed in one family houses owned by the interested participants in the information meetings. The energy consumption of the houses before and after installation of the solar heating system will be recorded and analysed. In this way the energy savings of a large number of solar heating systems with different designs can be determined. It will be elucidated how differently designed solar heating systems, houses and energy systems will influence the energy savings of solar heating systems
Results
Energy savings for a number of new solar heating systems in one family houses have been determined by means of information on the energy consumption of the houses before and after installation of the solar heating systems. The investigated solar heating systems are marketed by Velux Danmark A/S, Sonnnenkraft Scandinavia A/S and Batec Solvarme A/S. Solar domestic hot water systems as well as solar combi systems are included in the investigations The houses have different auxiliary energy supply systems: Natural gas boilers, oil fired burners, electrical heating and district heating. Some of the houses have a second auxiliary energy supply system. The collector areas vary from 1.83 m2 to 9.28 m2. Some of the solar heating systems are based on energy units with a new integrated natural gas boiler and a heat storage for the solar heating system. The existing energy systems in the houses are for most of the houses used as the auxiliary energy systems for the solar heating systems. The yearly energy savings for the houses where the only change is the installation of the solar heating system vary from 300 kWh per m2 solar collector to 1300 kWh per m2 solar collector. The average yearly energy savings is about 670 kWh per m2 solar collector for these solar heating systems. The energy savings per m2 solar collector is not influenced by the solar heating system type, the company marketing the system, the auxiliary energy supply system, the collector area, the collector tilt, the collector azimuth, the energy consumption of the house or the location of the house. The yearly energy savings for the houses with solar heating systems based on energy units including a new natural gas boiler vary from 790 kWh per m2 solar collector to 2090 kWh per m2 solar collector. The average yearly energy savings is about 1520 kWh per m2 solar collector for these solar heating systems. The energy savings per m2 solar collector for these systems are also not influenced by the solar heating system type, the company marketing the system, the auxiliary energy supply system, the collector area, the collector tilt, the collector azimuth, the energy consumption of the house or the location of the house. That is, yearly energy savings for new solar heating systems in one family houses are high, ranging from 300 kWh per m2 solar collector to 2090 kWh per m2 solar collector. If the existing energy system is used as the back up energy system for the solar heating system typical yearly energy savings vary from 500 kWh per m2 solar collector to 800 kWh per m2 solar collector. For solar heating systems with a new energy unit including a new natural gas boiler typical yearly energy savings vary from 1000 kWh per m2 solar collector to 2000 kWh per m2 solar collector
