An old building with three sustainable heating systems
The heat pump at the heart of energy efficiency and self-sufficiency
Eight years ago, the Böttcher family fell in love with an almost 40-year-old detached house in Egestorf in the Lüneburg Heath.
The houseowner Matthias realised from the outset that he wanted to renovate the house to make it more energy efficient. He designed his own heating system, which is designed for sustainability, independence and reliability.
Data and facts:
- Year of construction: 1972
- Conversion time (heating system): Self-managed conversion since 12/2021, installation of the heat pump (without pipework) within 3 hours
- Heated living space: 250 m2 (2 residential units)
- Number of residents and users of the heating system: 5
- Electricity consumption of the heat pump (02/2023 - 08/2023): 1,750 kWh
- Refurbishment measures:
Installation of underfloor heating in parts of the building, insulation of pipework and storage tank, partial replacement of windows
Anything but standard: three different systems supply the heat for heating and hot water in the Böttchers' home: a wood gasification boiler, a solar thermal system and a System E heat pump with the natural refrigerant R290. Together, they supply heat to five large buffer storage tanks with a total volume of 4,500 litres.
A photovoltaic system with a peak output of 16 kilowatts supplies the required energy and can also transfer its surplus production to two battery storage units. With their energy system, the Böttcher family is largely self-sufficient, requiring only a small amount of electricity from their electricity supplier.
The plans for the interaction between the various components of his heating system were drawn up by Matthias Böttcher himself. As a trained service technician for heat pumps, he knows exactly what he needs to bear in mind when renovating with heat pumps: ‘It was important to me not to rely on just one technology, but to create a system in which I can utilise the best of different heating systems and thus maximise energy and cost savings. If one heat source fails, we still have at least two other systems that can take over - so an energy crisis almost never hits us.’
The system is controlled centrally, so that the heating system that can currently produce the cheapest heat is always the first to be used. The heat pump is the latest system in the network. ‘We opted for a Dimplex System E heat pump because, firstly, it can be optimally adjusted for a mixed heating distribution system consisting of underfloor heating, panel radiators and old ribbed radiators,’ says Matthias Böttcher, ’and secondly, because I can be sure with this heat pump that it will work with the other components of the system without any problems - it does its job exactly when and how the overall system requires it to.’
For combination with renewable energies, such as a wood boiler or a solar thermal system, the heat pump can be blocked via the so-called regenerative mode if a sufficiently high temperature level is available in the regenerative storage tank.
In a bivalent system with an existing oil or gas boiler, the heat pump manager takes over comprehensive control. If required, it can access the fossil heat generator to optimise efficiency. In addition to controlling mixed and unmixed heating circuits, the heat pump manager takes care of domestic hot water preparation and can even control swimming pool heating if required. The special feature: System E is characterised by simple electrical connection options using colour-coded function blocks, which, together with the intelligent ‘EasyOn’ commissioning wizard, ensures effortless installation.
The requirements for all components of the heating system were high - including the heat pump: ‘Although the heating distribution system with radiators is getting on in years, it still works perfectly, so it should not be replaced immediately. Nevertheless, a heat pump should also provide energy-efficient heating. The prerequisite for this is that large quantities of water can be moved through the system at a correspondingly high flow temperature, and not every appliance can do this. Dimplex System E heat pumps, on the other hand, can. And it still remains efficient and quiet. An absolutely convincing combination.’
System E has been specially developed for efficient operation with radiators and achieves the highest efficiency ratings of A+++ even at flow temperatures of 55°C.
The new heat pump system is now a centrepiece of the Böttcher family's complex heating system, which will continue to evolve over the coming years. The WPM Touch heat pump manager, which regulates the heat pump and the heating curve of the living rooms, ensures the right temperature in all weathers. And System E also controls the temperature of the pool in the garden in conjunction with the solar system - and who knows what else is to come...