How does a heat pump work?

What is the operating principle of a heat pump?

A heat pump is a device that converts electrical energy into heat. However, its operation isn't as simple as that of a radiator or electric heater. This device utilizes thermodynamic processes such as compression, cooling, expansion, and heating of a heating medium. Because compression raises the temperature, we can extract this higher temperature indoors through a heat exchanger. Later, during expansion, the temperature drops significantly (up to -20 degrees Celsius). If the outside temperature is higher than the temperature of the expanded heating medium, after heating the medium, it can be recompressed, and the heat extracted. The space heating process occurs in a closed cycle.

How does a heat pump collect energy from outside the building?

Depending on the type of heat pump, it can extract heat from the environment (air-source heat pumps) or the ground (ground-source heat pumps). Heat exchangers are an important element of a heat pump. They are responsible for transferring thermal energy to the interior of the building and for extracting cooling from the working fluid on the exterior of the building. 

Types of heat pumps

What are the differences between a split and monoblock heat pump?

A monoblock system assumes that the entire system, with the heating medium, is outdoors, and from there, heat is drawn for central heating and domestic hot water. In a split system, the heating medium system is more complex, as it enters the apartment/house, where a heat exchanger is located to extract the generated heat from the medium. This involves certain losses in the medium's compression due to the longer transport distance. Interestingly, split systems are cheaper. Therefore, both choices will be successful: one has lower investment costs, and the other lower operating costs.

Comparison of ground and air pumps

The key differences between them are price and efficiency. Ground-source heat pumps are more expensive due to the required groundwork. These include vertical drilling or horizontal installation, usually depending on the available ground area for installation or soil parameters. It's difficult to estimate the difference in investment costs, but it typically ranges from 10-401 TP3T. Because the underground temperature remains stable throughout the year, reaching as much as 10 degrees Celsius, its COP is also constant. This is a crucial parameter, providing information on how many kWh of heat will be generated per kWh of electricity supplied to the pump. In the case of an air-source heat pump, this COP is lower on average throughout the year and fluctuates depending on the air temperature. 

Because the external unit of an air-source heat pump is usually located somewhere near the house, the compressor, fan, and possibly other components generate some noise. This noise is comparable to that of a refrigerator, so in most cases, it's a minor aspect of this type of heat pump.

Heat pumps are also used for air conditioning, so they can also operate in reverse circulation. In this case, ground-source heat pumps are also much more effective, requiring significantly less energy to cool rooms than air-source heat pumps.

Heat pump installation

What are the costs of installing a heat pump and how is the heat pump installed?

Of course, it depends on whether you choose a monobloc or split heat pump, ground-source or air-source, the surface area you want to heat, the building's insulation, whether it will be the building's primary heat source, and the specific manufacturer. These factors mean that the price of a pump, including installation, can range from PLN 25,000 to as much as PLN 140,000. However, it's important to remember that numerous subsidy programs are available for this technology, so it's worth contacting us for details.

In the case of ground PCs, earthworks additionally extend the installation time, while the standard installation time was approximately 2-4 working days by a team of technical workers.

Are additional underfloor heating installations needed?

Generally, in most cases, this won't be necessary. However, it's worth discussing a specific project with our specialist to ensure that your home's heating will be as efficient when switching from a gas or oil boiler to a heat pump, for example.

Financing and subsidies for heat pumps

What subsidies are available for the purchase and installation of a heat pump?

The program most investors take advantage of is the government's "Clean Air" program, which has been running for several years. It allows for reimbursement of up to PLN 70,000, depending on the planned dismantling of the previous heat source and heating system, the purchase of the heat pump system, and installation services. Even higher subsidies are available if, in addition to the heating system, the owner plans to thermally modernize the building or install a photovoltaic system. Importantly, the program takes into account the participant's income criteria. Those with the lowest incomes can count on the highest subsidies, while those earning over PLN 135,000 per year are not eligible for any subsidies.

What other grants are available besides Clean Air?

What to pay attention to when choosing the best heat source

Heat pump efficiency

A pump's COP (Coefficient of Power) is its ability to convert electricity into heat. In the case of heat pumps, this coefficient is greater than 1. 

The higher the value, the better for your energy bills. For high COPs, just a few kilowatts of energy are enough to provide sufficient heat most days of the year. 

If we have been using electric heating so far, the COP coefficient shows us how much we will save on heating costs if we start using a heat pump. 

Installation costs and operating costs

The price range of devices on the market is very wide and usually depends on the technology, power, efficiency, durability, and ease of use. Installation prices by different teams may also vary. 

The cost of operating a heat pump is not only related to the amount of energy consumed by the heat pump and electricity prices, but also to the cost of periodic inspections. In the case of heat pumps, it's advisable to annually check the condition of the system components and, if necessary, top up the heating medium. Often, these inspections are also crucial to maintaining the manufacturer's warranty.

Pump power and operating temperature range

The power of a heating device is selected based on many factors: usable area, insulation thickness, heating profile, and number of household members. The selected heat pump technology, the presence of an alternative heat source, and the type of heating system (underfloor heating or radiators) are also important. Companies offering heating systems often input this data into the systems, which returns the thermal energy demand. They then convert this data into thermal power. After taking into account the COP coefficient, the analysis results in the heat pump's electrical power. Based on this result, a specific device is selected to meet the heating demand. 

Temperature range is crucial for air-to-air heat pumps because outdoor air temperatures fluctuate significantly throughout the year, causing the COP to fluctuate between 0.9 and 5. When the air temperature drops below -20 degrees Celsius, the heating medium must be heated by a heating element to maintain the appropriate indoor temperature. The electric heating element, of course, consumes energy, which significantly reduces the COP. Such low temperatures have become extremely rare in recent years, which is why air-to-air heat pumps are becoming increasingly popular. 

Service – comfort of use and mobile access

Heat pump systems are now highly automated, and most even have mobile apps for monitoring and controlling their operation, receiving alarms, and contacting the installer or manufacturer's service center. If this convenience is important to you, our consultant will certainly present you with solutions that meet your needs.

Summary

Heat pumps are somewhat more complex systems than gas boilers or electric heating. Because they utilize heat that occurs naturally in nature—in the air, in the ground, or in bodies of water—they are classified as renewable energy sources. 

There is also a solution on the market called a hybrid heat pump, which is normally powered to a specific outside air temperature and then uses gas fuel, most often natural gas, for central heating and a domestic hot water tank. 

A heat pump can also work very well with photovoltaics, a small wind turbine, an energy storage device or a heat buffer, allowing you to create a partially independent energy system based on renewable energy sources that will ensure low operating costs for your household or farm.