Heat pump combined with condensing boiler
In cooperation with a supplier of energy plants we are going to examine in practice, a combination of a heat pump and a condensing gas-fired boiler in a boiler room that provides central-heating to a building.
In cooperation with a supplier of energy plants we are going to examine in practice, a combination of a heat pump and a condensing gas-fired boiler in a boiler room that provides central-heating to a building.
By establishing a system consisting of a heat pump combined with a gas-fired condensing boiler, the synergy of the two technologies can be combined so as to achieve a high COP-factor for the heat pump, while the condensing of the boiler will be more efficiently, without adaption of the existing heating system.
The test is intended to provide clarification about whether the combination in practice provides the expected energy efficiency improvement of the boiler, how the relation between the heating capacity of the heat pump and the boiler should be, and how operational strategy can be adapted to varying electricity prices over the day.
The project idea was to take two known components: a condensing boiler and a heat pump and build them together in a new and unconventional way. The heat pump is used to reduce the return temperature of the boiler, increasing the condensation of the flue gas and improve boiler efficiency.
It has not been possible to obtain the promised COP value of 3.46, The average COP value was 3.08 in the reference year - lowest in May to August. It is not fully uncovered why the promised COP value is not achieved, but it is probably due to a combination of:
- short ground collectors in relation to the operating hours (7,900 hours in one year) and
- high operating temperature (57°K) in the summer months.
In comparison to the boiler operating without the heat pump, the boiler efficiency was improved by 3.3 %. The energy savings was 26%, which is higher than the expected 10-20%. The saving on heating costs was 12% and is entirely due to a partial reimbursement of the electricity tax. If the partial reimbursement of electricity tax is not included, this project has no economic benefit.
Key figures
Category
Participants
| Partner | Subsidy | Auto financing |
|---|---|---|
| ROBERT BOSCH A/S | ||
| Ejerforeningen Nørrelundparken |
