Waste water recovery in combination with heat pump(s) - measurements
The project tests how heat pumps can be integrated into energy renovation and new build by covering the heat demand. The heat pump is used to recover heat from the building's wastewater before the wastewater is fed to the sewer system. In this way, the solution contributes to increasing the electrification of the total energy consumption of buildings, and it becomes more economically attractive to invest in heat pumps, as an alternative to oil and natural gas boilers and in district heating areas. Wastewater heat recovery makes it possible to develop the innovative PVT-E energy plants for CO2-negative energy supplies. Because of the solution's built-in storage potential, it can also be included in Smart Grid concepts.
Large amounts of heat are flushed out with the waste water. In newer homes, consumption for heating domestic hot water is up to half of the home's heat consumption. This amount of energy is usually just lost in the sewer. An effective recovery of this part of heat therefore represents a great potential for reducing the heat consumption in homes. The potential is documented and demonstrated, but in practice not exploited due to a number of barriers.
The project will show that this potential can be exploited through a combination with heat pumps. The waste water is a supplement or alternative to traditional heat sources for heat pumps and helps heat pumps to be used in several places and run with higher efficiency.
The focus is on larger homes, multi-story housing or close/low housing with a common sewer system. We will analyze plants that supply only hot water and plants that also supply space heating. Installations with heat pump for domestic hot water can only potentially cover the entire heat demand, supplemented by direct electricity. Installations that also supply for heating can potentially supply all heat to the home with supplementary heat source to the heat pump, so that existing gas or oil stoves can be shut down. The combination with PVT (combined solar cell and solar collector) is a new technology that is favorable and which will therefore be included in the project. The demonstration will be through participation in development work and planning in connection with ongoing projects. A number of projects will be followed and analyzed and passed on through experience and design parameters.
The technology is relevant in new construction and in connection with renovation. The target group for the project is the construction industry broad, consultants, housing organizations, project developers, etc.
Large amounts of heat are flushed out with the wastewater. In newer well insulated homes, consumption for heating domestic hot water is up to 40% of the buildings heat consumption. This amount of energy is usually just lost in the sewer. An effective recovery of this part of heat therefore represents a great potential for reducing the heat consumption in buildings. The potential is documented and demonstrated, but in practice not exploited due to several barriers such as lack of references and design rules as well as cost.
The project shows that the potential can be exploited by use of special heat exchanger systems and heat pumps. The wastewater is a supplement or alternative to traditional heat sources for heat pumps, resulting in exploitation of more heat pumps and operation with higher efficiency.
The focus is on larger residential housing like multifamily housing and terraced housing with a common sewer system. We have analysed plants that supply only hot water as well as plants that also supply space heating.
The technology is relevant in both new construction and in connection with renovation. This project has focused on tests of heat pumps that are integrated into the energy supply of renovated buildings to cover part of the heat demand. The heat pumps are used to recover heat from the building's wastewater on the way to the sewer system. In this way, the solutions contribute to increase the electrification of the total energy consumption of buildings. The potential high efficiency of the heat pump (COP) and surplus power from PV panels on the buildings during summer makes it more attractive to install such heat pumps, as an alternative to oil and natural gas boilers, and as well in district heating supplied areas.
The project shows that the heat pumps can operate efficiently with COP's of above 4, and that costs reductions are possible. The learning curve shows a clear trend towards lower cost as bidders get more use to the technology and more standardized solutions are introduced. Combined with attractive financing sources and utilization of PV power during summer, the systems can be justified economically, especially in connection with upgrading of social housing and as well in connection with new buildings.
The project also shows the need of professional adjustments and commissioning during start-up, continuous surveillance service with phone notifications and a caretaker to reset heat pump alarms when occasionally needed to ensure continuous operation. Otherwise, the operation has been trouble-free and robust with no breakdowns.
The target group for the project is the construction industry, consultants, housing organizations and project developers.
Key figures
Category
Participants
| Partner | Subsidy | Auto financing |
|---|---|---|
| METRO THERM A/S | ||
| Boligselskabet KAB | ||
| Stengården, afd. 8 under Stenløse-Ølstykke Boligforening | ||
| Rubrik |
