Power to Heat as a building block of modern heating and energy concepts

The energy transition in the building sector is increasingly being determined by one central question: what happens to the electricity generated by photovoltaic systems if it cannot be consumed directly in the household at the moment of production? With the rapid expansion of PV modules on residential and commercial buildings, the proportion of surplus energy that is neither fed into the grid nor used immediately is growing. This is precisely where concepts such as Power to Heat are gaining in importance, because they build a direct bridge between electricity generation and heat utilisation.

Converting electricity into heat and storing this heat efficiently is not a new technical principle. What is new, however, is the combination of modulating power, compact design and systemic integration into existing heating and storage structures. This transforms Power to Heat from a theoretical addition to a practical solution for many types of buildings – from new builds to existing properties.

Cosmo as a component manufacturer in the heating sector

Cosmo has been active in the market as a manufacturer for the sanitary and heating industry for around two decades. The focus is not on its own heat generators, but on components related to heat distribution and heat generators. These include buffer storage tanks, control technology, pump groups and solutions for surface heating systems such as underfloor heating. This positioning makes it possible to combine different heat generators and energy sources without committing to a single heating system. Against the backdrop of the growing PV market, Cosmo is focusing on the question of how surplus solar power can be used sensibly. The answer is a modulating power-to-heat module that is specifically tailored to the company's own buffer storage tanks. The aim is to convert electrical energy from photovoltaic systems directly into heating water and store it in the storage tank.

Modulating power-to-heat module for PV surpluses

The system presented does not rely on a fixed power level, but works in a modulating manner. This means that the feed-in power flexibly adapts to the actual available PV surplus. Even small amounts of power of a few hundred watts can be used, while with higher surpluses, the feed-in power increases to the kilowatt range. This prevents electricity from remaining unused or only being able to be processed in large increments. The surplus electricity is fed directly into the buffer storage tank via the power-to-heat module. There, heating water is heated, which is then available either for domestic hot water preparation or for space heating. The storage tank acts as a thermal energy storage unit, which can absorb large amounts of energy compared to electrical battery storage units. The close coordination between the module, storage tank and control system is technically crucial. The pump group ensures that the heating water is circulated in a targeted manner and the storage tank is charged when power is available. The control system continuously monitors the available amounts of electricity and adjusts operation accordingly.

Advantages over conventional solutions

A key difference to many competing products is the compact design and low entry threshold. The module works reliably even at very low feed-in capacities and increases its output continuously as the PV surplus grows. This enables continuous use of solar power even in changing weather conditions. The system concept can be summarised in several points:

• Direct conversion of PV electricity into heating energy
• Modulating operation instead of fixed power levels
• Integration into existing buffer storage tanks
• Increase in own consumption of solar power
• Relief of the electricity grid through lower feed-in

Extensive electric heating as a further approach

In addition to the power-to-heat module, Cosmo also presents solutions for fully electric heating of buildings. A central element here is a heating fleece that can be integrated directly into walls, ceilings or floors. The fleece is operated at low voltage and delivers a defined heating output per square metre. It is installed over a large area under a filler or behind wall coverings, integrating the system invisibly into the building structure.

In well-insulated new buildings, this concept opens up the possibility of completely dispensing with classic water-based heating systems. In combination with photovoltaics and, if necessary, an electric storage unit, fully electric heating can be achieved. The Building Energy Act also provides for subsidies for such concepts, which further increases their attractiveness. In existing buildings, heating fleece is currently used primarily as a problem solver. Typical applications can be found in window reveals or critical wall areas where mould tends to form. Targeted heating of surfaces can reduce moisture problems without the need for extensive structural measures.

Classification in the context of the energy transition

The solutions presented show that the energy transition in the building sector is not being driven solely by new heat generators. At least as important are intelligent components that sensibly direct and link existing energy flows. Power to heat is not a substitute for heat pumps or other heating systems, but rather a complementary component that is becoming increasingly important, especially with high PV penetration. In this environment, Cosmo positions itself as a supplier of systemically coordinated components that can be flexibly combined with different heating and energy systems. The combination of buffer storage, modulating power control and surface heating solutions illustrates that the focus is not on individual products, but on functioning overall concepts. In the long term, it is precisely this system perspective that is likely to determine how efficiently and economically renewable energies can be used in existing buildings. Power to heat is less a short-term trend and more a logical step towards a more electrified and, at the same time, heat-oriented energy supply.