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What exactly is a heat pump?
Heat pumps use free ambient heat to generate energy for heating or hot water.
Depending on the season, we might sometimes walk across the garden lawn with thick boots on, and sometimes barefoot. All the while, the temperature just a few meters under our feet remains constant the whole year round. Ten metres below ground, it’s about 15 degrees Celsius. This is a high enough temperature for heating and for heating water for taking a shower or a bath. All that’s needed is a geothermal probe and a heat pump.
Heat pumps 'collect' the heat from the ground and concentrate it until heat is generated that can be transferred to a hot water storage tank, for example. In principle, they work like a refrigerator – only the other way round. How so? A refrigerator works by removing the heat from the food and releasing it externally. With a heat pump, the aim is to harness the heat from the environment to use it for heating or for making hot warmer.
Turning ambient heat into energy
The heat from the environment is used to heat a liquid coolant in the heat pump, causing it to evaporate. After this, a compressor is used to turn the heated, gaseous coolant into the required density and then to compress it. During this process, the coolant becomes even water. In the heat pump, the hot, gaseous coolant now transfers its heat to a heating system or hot water storage tank, after which it cools and becomes liquid again. The coolant is then further 'relaxed' and able to expand via what is known as an expansion or throttle valve, reducing the pressure of the coolant flowing through the system. As a result, it continues to cool down and can then absorb heat from its surroundings again. The heat pump cycle is then ready to start again.
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How the environment provides us with free energy
Modern heat pumps can work very economically. Depending on the model, only part of the usual amount of electricity is required to generate the heat needed for heating or for making hot water. The heat pump takes exponentially more energy from the ground, the groundwater or the air.
The resources are available for free and are inexhaustible. As a basic rule, the higher the initial temperature of the heat source, the less electricity is required and the more efficient the heat pump is. The efficiency is increased even further if the target temperature is not too high. Heat pumps are therefore particularly suitable for installation in well-insulated houses that can be heated at relatively low temperatures. This is the case if, for example, underfloor heating is installed that runs on a low flow temperature.
The heat pump is 100 percent climate-neutral
Sound good? A heat pump can be up to 100 percent climate-neutral if the electricity needed to operate it is also generated from renewable energy, for example if green electricity is used or the heat pump is combined with a photovoltaic system on the roof of the house. Anyone planning to purchase a heat pump should pay attention to a number of key points: selecting the right heat source (preferably soil), the optimum size, tolerable noise emissions and an environmentally friendly refrigerant.
The Federal Government provides funding for purchasing and installing efficient and environmentally friendly heat pumps in private homes. For a geothermal heat pump with a probe, minimum grants of €4,500 are available under the Market Incentive Programme for 'Heat from Renewables' (MAP), for example.