How does an air heat pump work?
An air source heat pump is one of the most popular solutions in the field of building heating and cooling. It operates by extracting heat from the outdoor air and transferring it to indoor spaces. By utilizing renewable energy, air source heat pumps help save on heating costs. If you want to find out exactly how air source heat pumps work, read the article below. Air source heat pumps are characterized by simple and fast installation and high efficiency. During winter, they can provide warmth to spaces, while in summer, they can be used for cooling. This makes them a versatile and economical solution for both single-family homes and industrial facilities.
What Are Air Source Heat Pumps?
Air source heat pumps are devices that utilize energy from the external environment - the air to heat or cool spaces or to heat domestic water in homes and buildings. By utilizing renewable energy from the surroundings, heat pumps are more energy-efficient and environmentally friendly than traditional heating systems based on fossil fuel combustion.
Air source heat pumps can be used in both new buildings and for the modernization of existing heating systems. They can also be used in conjunction with other heat sources, such as solar collectors. When installing an air source heat pump, it is important to provide adequate space for the device and perform regular maintenance to maintain its efficiency. Heat pumps are becoming an increasingly popular solution in the field of energy-efficient heating technologies, providing users with financial savings and reducing greenhouse gas emissions.
Types of Air Source Heat Pumps - Classification by Medium
We distinguish two main types of air source heat pumps based on the medium used. The first type is the air-to-air heat pump, where heat is extracted from the outdoor air and transferred indoors. The second type is air-to-water, where heat is extracted from the outdoor air and transferred to the heating system to heat water. Below, we describe each of these types in more detail.
Air-to-Air Heat Pump
Air-to-air heat pumps are inexpensive, widely used, and can serve two functions - heating the indoor air or cooling it (the pump then functions as an air conditioner). Heat is extracted from the outdoor air and transferred to indoor spaces. As a result, air-to-air heat pumps are quite energy-efficient and environmentally friendly.
In winter, they can effectively heat interiors, providing thermal comfort. On hot days, they can act as air conditioners, removing heat outside and providing pleasant cooling. Due to their versatility, air-to-air heat pumps are a good solution for homes and buildings with various thermal needs.
Air-to-Water Heat Pump
Air-to-water heat pumps are efficient heating systems that can serve as the main source of heat in homes and buildings. They utilize energy from the outdoor air to produce heat, which is then transferred to the heating system.
Moreover, air-to-water heat pumps are also used to heat domestic hot water in households. This not only provides warmth for heating spaces but also supplies hot water for daily use. This is a significant advantage over air-to-air heat pumps. These benefits make them a popular choice for individuals who want to efficiently heat both indoor air and domestic water.
Types of Air Source Heat Pumps - Classification by Construction
Types of air source heat pumps can be divided by construction into monoblock and split pumps. Monoblock consists of a single unit containing all components (compressor, condenser, evaporator with fan, expansion valve, and circulation pump). These pumps are easy to install and do not require much space, but they are less energy-efficient. Split-type pumps mean that the indoor and outdoor units are separated. The indoor unit is installed inside the building, and the outdoor unit is installed outside. These pumps are more energy-efficient but require more work during installation.
Monoblock Air Source Heat Pump
Monoblock air source heat pump is a device that can be mounted either inside or outside the building. Internal placement results in more noise but longer lifespan due to controlled conditions regarding temperature and humidity. On the other hand, outdoor installation reduces the noise generated by the device during operation, but in this case, it will be necessary to protect the installation from freezing.
Monoblock pumps are one of the most commonly chosen types of heat pumps due to their numerous advantages. One of them is the possibility of quick and easy installation, making it an ideal solution even for small facilities.
Split Air Source Heat Pump
Split-type air source heat pump consists of two units (external and internal) connected by pipes. It is a device that is installed and filled with refrigerant by an appropriately trained and authorized installer. The installation of a split-type pump is a precise process that requires accuracy and knowledge of the system's operation principles. The installer must also know how to handle refrigerant safely. The installation requires proper site preparation and connection to the power supply. Air source heat pumps of the split type are popular due to their energy efficiency and the possibility of dividing the system into external and internal parts, which eliminates the noise problem in the building. Their advantages also include:
- no risk of freezing due to filling the installation with refrigerant instead of water,
- easy transportation,
- low heat loss.
Operation Scheme of Air Source Heat Pumps
Air source heat pumps are becoming increasingly popular and effective heating devices. Their main function is to use the heat available in the outdoor air to heat domestic hot water and heat or cool the house.
The operation scheme of these devices is based on the use of a thermodynamic cycle, which allows for the extraction of heat from the external environment and its transfer to the inside of the building. Thanks to heat pumps, significant energy savings can be achieved, speeding up the return on investment. The principle of their operation will be explained in more detail below.
First Cycle and Lower Heat Source
The lower heat source is the place from which heat is extracted and transferred to the heating system. In an air source heat pump, this is the outdoor air.
In the first cycle, a fan draws air from outside the building and delivers it to the evaporator. In the evaporator (a type of heat exchanger), there is a refrigeration system filled with refrigerant. The temperature difference between the refrigerant and the air allows heat transfer between these media. The refrigerant absorbs heat from the air, even when the temperature outside is negative. As the refrigerant absorbs heat from the air, it evaporates, changing its state from liquid to gas. In the next step, the heated and expanded gas is transported to the second cycle.
Second Cycle
The gas-like working fluid enters the compressor, where it is compressed (increasing pressure) and heated to an even higher temperature. Then the compressor pumps the vaporized refrigerant to the condenser.
Third Cycle and Upper Heat Source
The upper heat source in an air source heat pump is a term used to describe the heating system used to heat the air or domestic hot water in the building.
In the third cycle, the working fluid in the form of compressed gas at high temperature enters the condenser (heat exchanger), where condensation takes place, i.e., the gas is converted into a liquid. The condenser is washed with heating water. As a result of this process, heat is transferred, and the heating water used to heat the building is heated, while the working fluid is cooled and liquefied.
The final step is the return of the liquefied refrigerant to the evaporator through the expansion valve, where there is a decrease in pressure and temperature of the refrigerant to values achieved at the beginning in the evaporator.
The above cycles repeat cyclically.
If you want to install a monoblock air source heat pump - and to protect it from freezing, you decide to fill the circuit with glycol - you will need to select the appropriate plate heat exchanger - to connect the glycol circuit with the heating circuit in the house. In our offer, you will find a full catalog of heat exchangers designed for connecting heat pumps - both small units and quite large systems.