Heating systems utilizing heat pumps harness ambient warmth to achieve multiple savings in energy consumption for heating purposes. In this article, discover how heat pumps operate, their benefits and drawbacks, pricing considerations, and heating cost savings.
The Rise of Renewable Energy Usage
In recent years, the utilization of renewable energy sources has gained significant momentum. When coupled with environmental considerations, the integration of renewable energy sources results in even more compelling narratives. Heat pumps seamlessly fit into this narrative as one of the cleanest sources of heating energy, also being the most cost-effective.
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Unlike other renewable energy sources like solar energy and wind power, heat from the surroundings (earth, water, air) remains consistently available throughout the year. Notably, in Switzerland, every third new construction is equipped with some form of heat pump, while in Sweden, it’s 7 out of 10, and in Germany and Iceland, one-quarter of new constructions.
Today, technical flaws in these systems, which experienced their initial expansion in the early 1980s, have been rectified, making this heating method highly reliable.
Operating Principle of Heating Heat Pumps
Heat pumps are devices facilitating the transfer of thermal energy from a lower-temperature environment (earth, water, air) to a higher-temperature system (central heating) using additional energy – namely electricity to power the compressor.
The operating principle of heat pumps is straightforward and can be likened to that of a refrigerator. In fact, it’s the same principle. For instance, in a heat pump system utilizing thermal energy from groundwater, the operational principle is as follows: Water with an average temperature of 12 to 15 degrees Celsius (approximately 35.6°F to 59°F) is extracted from a well and introduced into a Freon evaporator. Freon, evaporating at a very low temperature, absorbs a portion of the thermal energy from the groundwater, and the cooled water returns to its natural underground flow.
The Freon, having absorbed some of the thermal energy from the groundwater during the evaporation phase at low temperature, returns to the compressor where it is compressed, releasing thermal energy transferred to the central heating system through another heat exchanger. Similar to how Freon in the heating system absorbs the temperature of the groundwater and transfers it to the heated building, a refrigerator absorbs temperature from its interior where the food is stored and transfers it to the room via the heat exchanger (the black grid behind the refrigerator).
Thus, through this process, the heating system utilizing a heat pump produces 4 kW of thermal energy for every 1 kW of electrical energy invested. It might seem like a perpetual motion machine or a device contradicting the basic principles of physics and thermodynamics by producing energy from nothing, but that’s not the case.
The heat pump simply extracts thermal energy from the surroundings and transfers it to the building, with the costs being the energy consumed by the compressor, operational costs, and system losses.
Types of Heat Pumps
Depending on the environment or the most efficient method to “harvest” thermal energy from the surroundings, various heat pump systems exist:
- Water-to-Water Heat Pump: Works on the previously explained principle. Thermal energy is extracted from groundwater and transferred to the water in the central heating system. This heating type is the most efficient but also the most demanding in terms of installation and initial investment.
- Ground Source Heat Pump: Extracts thermal energy from the ground and transfers it to the water in the central heating system via pipes. The installation is similar to water-to-water systems. There’s a system with horizontal pipe laying beneath the ground surface, which is simpler but less efficient. It’s crucial to ensure that the surface over which the pipes are laid doesn’t bear significant weight at any given time to prevent damage. Additionally, pipes are laid on land where there’s no possibility of constructing another building, making this solution suitable for rural properties with ample space. While laying collectors one meter deep in the ground requires extensive earthworks and relatively large free land area around the property, digging ground probes using modern drilling equipment requires less time and fewer preparatory works. For installations with ground probes, determining the probe layout and drilling depth is crucial, and the installation of probes heavily depends on the characteristics of the soil, which are determined on-site.
- Air-to-Water Heat Pump: Extracts heat from external air and transfers it to the water heating the home. Installation of this pump requires minimal investment.
- Air-to-Air Heat Pump: Functions similarly to all the previous types, except instead of transferring heat to water, it transfers heat extracted from external air to the air inside the heated spaces.
Is Installing a Heat Pump Worth It?
The cost of installing a heating system using a heat pump depends on the type of heat pump used (water-to-water, ground source, air-to-water, etc.), and the most suitable solution depends on the property itself, its location, surroundings, etc. Approximately, a water-to-water heat pump, which draws energy from groundwater, costs around €3,500 to €4,000 for a 150-square-meter house, with the entire system costing around €7,000 (1000 euros is approximately 1070 dollars).
Investing in a heat pump system is significantly higher compared to other heating systems, so in this case, it takes a minimum of five years for the initial cost to pay off. The water-to-water heat pump system is more expensive than the air-to-water system but is much more efficient and stable at low temperatures. Heat pumps where the heat source is the air are much cheaper and easier to maintain. Practically, with them, there’s no maintenance; once installed, the Freon is filled, and they operate for years without issues, much like air conditioning units.
Prices of air-to-water heat pumps range from €3,500, with the best-selling models having a power of eight kilowatts and costing around €4,000, while pumps with a power of 16 kilowatts cost over €8,000 (1000 euros is approximately 1070 dollars). The conclusion is evident – investing in a heating system with heat pumps requires significant initial investments, which are too high for most, and actual heating savings can only be realized after several years, with noticeable reductions in bills being apparent only for larger properties.
The relatively high price is the main reason why such heating systems are much more popular in the most developed countries, where there’s more money, but also a greater emphasis on environmental preservation.
Foto: LG