Heating with a heat pump: is that climate-friendly? - Utopia.de

Anyone who researches sustainable heating often ends up with the heat pump. We explain to you how climate-friendly the technology really is and how it works.

The heating structure in Germany was as follows in 2020: almost 50 percent of households heated with natural gas. Another 25 percent got their heat from heating oil. At 17.1 percent, district heating is the last major pillar of heating sources. The remaining households obtained heat from various sources: wood and wood pellets, coal, electricity and also with the help of a heat pump. These numbers pose a major ecological problem - they do not fit with our climate goals. A rethinking and practical implementation is urgently needed. Read more about this in this article: Why a heat transition is necessary.

In 2020, 40 percent more heat pumps were installed than in the previous year. In newly built buildings, heat pumps are even ahead of gas heating (38.7 percent) at 46 percent. But overall, just 2.6 percent of German households use this heat source.

Heat pumps are relatively climate-friendly. If you operate them with green electricity, they are mathematically almost CO2-neutral in operation. Here you can find out exactly what a heat pump is, what subsidies are available for it and you will get an overview of the advantages and disadvantages. Also, a heat pump is not necessarily the best solution for everyone. In order for it to be meaningful, certain factors must apply.

What is a heat pump and how does it work?

The basic principle of the heat pump is very old. However, heat pumps have only been mass-produced since the 1990s. Until a few years ago, it was more of a niche product.

A heat pump consists of three parts:

1. A system that extracts thermal energy from the surrounding sources,
2. the pump that makes use of the environmental heat obtained,
3. and the system that distributes and stores the heat .

How it works: The heat pump makes use of the physical principle that there is thermal energy in all materials. Even if their temperature is below zero degrees Celsius. Thermal energy is nothing but the movement of atoms and molecules. The warmer something is, the faster these particles move.

1. In the beginning, the heat pump requires drive energy in the form of electricity. However, this is not lost, but is added to the heat energy gained in the course of the process.
2. The initially liquid refrigerant circulating in the heat pump extracts heat from the environment and evaporates in the process. During this process, it changes its state of aggregation.
3. The heat pump can use the drive energy to compress the heated refrigerant.
4. During compression, the particles of the substance accelerate, generating friction and thus heat. The so-called flow temperature is created. This is between 30 and 50 degrees warm.
5. The heat is transferred to the heating system, which leads into the house, via a heat exchanger.
6. The refrigerant becomes liquid again when it cools down and is returned into the heat pump.
7. The cycle can start all over again.

Almost everyone has some kind of heat pump at home, except this The principle here is reversed: the refrigerator. This will make it easier for you to visualize the process. A liquid coolant absorbs the thermal energy from inside the refrigerator and channels it outside. Thus, the temperature inside decreases. You can usually feel that it's warm at the back of the fridge. This is also the reason why you can even use a heat pump as an air conditioner in summer.

What types of heat pumps are there and what makes them different?

A certain parameter is helpful for understanding the following paragraph: the so-called annual performance factor, abbreviated to JAZ. It shows the relationship between the electricity required and the heating energy produced. The JAZ is very important for anyone who wants to compare heat pumps. An example of the calculation: With a supply of 5,000 kilowatt hours of electrical energy, a heat pump produces 20,000 kilowatt hours of heating energy. Here the JAZ would be four. Four times more heat is produced than electricity is consumed.

The main types of heat pumps are as follows:

When does a heat pump make sense?

As indicated at the beginning, the heat pump is not a blanket solution for a clean heat source. According to the consumer center, under certain circumstances it is more inefficient and its advantages turn negative. That's why you should take a closer look in advance if you're thinking about using a heat pump. According to the consumer center, these are some of the conditions that must be met:

1. The heat pump only makes sense from a JAZ from 3. The higher the JAZ, the more efficient the heating system. Therefore, a heat pump with the high ACV is always to be preferred. If a heat pump has a very low ACV, it can become a real energy waster. It should also be noted that in reality the JAZ is often below the number specified by the manufacturer. It is therefore better to count on a more efficient heat pump from the start.
2. A heat pump requires certain infrastructural requirements. For example, are drilling possible? Heat pumps are designed more for houses and not, for example, for condominiums.
3. A heat pump only makes sense if the house is well insulated. Otherwise it would become unnecessarily expensive in terms of electricity consumption and another heat source would be more efficient.
4. A heat pump almost always requires surface heating (floor or wall) for its operation. This is because the heat produced is usually no more than 50 degrees Celsius. A small radiator, as we know it from oil or gas heaters, would therefore not be enough to heat an entire room. You should therefore clarify whether, for example, underfloor heating can be installed in your home.

There are many other such factors that play a role in the decision for a heat pump. Therefore, you should always seek expert advice beforehand.

Cons:

Our conclusion on the heat pump

Heat pumps are an important step towards a more climate-friendly society. They have great potential to be the heat source of the future because they work without burning fossil fuels. For them, no raw material has to be cultivated, as is the case with burning wood. There is great opportunity in this independence.

On the other hand, the potential of heat pumps depends on many factors. It's hard not to lose track of things. What is certain is that the development of this technology is not yet over - for example in terms of efficiency. In order to make progress in research, heat pumps that are already in operation need to be monitored. At the Fraunhofer Institute ISE, for example, there are still opportunities to get involved. If you don't want to rule out a heat pump, be sure to get an expert opinion. Possibly all conditions are favorable for you, so that a heat pump makes sense.

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