When our engineers are onsite carrying out annual health checks on our installations, they collect metered data from the sites that have heat meters installed for RHI purposes. This information tells us how much heat is being generated by the heat pump. As we always fit electricity meters on our heat pump installations, we are able to see how much electricity is being used to generate the heat and therefore calculate the seasonal performance factor (SPF) of the system since it was first switched on. This enables us to compare and contrast different heat pump manufacturers, different collector designs, the performance of different building types and different types of heat emitters and the effect of additional loads such as swimming pools and cooling.
Looking at the latest data added to our systems from recent annual maintenance visits for two very different buildings, the numbers highlight the high performance of our systems.
Site 1 - New build private house with additional period cottages heated from a centralised plant room. 51kW CTC GSHP system from horizontal collector array installed to provide all heating and hot water. Heating delivery via a mix of UFH and radiators.
- SPF - 4.06
Site 2 - Existing 1980's Church. 100kW Ecoforest inverter driven GSHP from boreholes installed to provide all heating. Heating delivery via radiators.
- SPF - 4.08
If we look at data we have collected when servicing other companies’ installations, we see a different story. One recent system we surveyed was shown to be running at an SPF of 2.1 whilst doing heating only. Some investigation uncovered that the heating was set to run at 50 degrees even when the outdoor temperature was 22 degrees. This misconfiguration makes the heat pump more expensive to run than an oil boiler.
A full recommissioning of the system will be required to set the system up correctly. Luckily this site has the main elements of an efficient system in place. It is just badly put together and commissioned. Not all sites are as lucky and we regularly see poor performing systems with frozen ground arrays or boreholes which require much more extensive remedial works to bring them back up to an acceptable efficiency.
If you are considering a ground source heat pump it is important to satisfy yourself that the quoted expected SPF for the system is realistic and obtainable. Contact isoenergy today and start enjoying a return on your investment earlier than the unfortunate owners of the system above. By choosing to save money on the installation costs, they have lost money with the higher running costs.
