Heat pumps are the most energy-efficient form of heating for properties.
This is how the heat pump works
The operation of heat pumps is based on the refrigerant process familiar from refrigerators and freezers. A heat pump consists of an evaporator, a condenser, a compressor and an expansion valve. In an air heat pump, the outdoor and indoor units correspond to the evaporator and the condenser. The outdoor and indoor units are connected by copper refrigerant pipes. Refrigerant pipes transport the refrigerant heated in the evaporator to the compressor, which raises the pressure in the refrigerant. As a result of the work of the compressor, the temperature of the refrigerant rises to a temperature of 50 – 68 °C, depending on the heat pump. After the compressor, the hot gas goes to the condenser, where, after turning into a liquid, it releases the thermal energy bound from the outside air or the collection circuit to heat the apartment. When cooling the apartment, the outdoor and indoor units of the air heat pump work in the opposite direction, i.e. the refrigerant circulates in the opposite direction in the process.
Heat pumps are always heat sources, they do not replace the ventilation of the house. It is often mistaken to think that the air heat pump changes the outside air inside, but this is not the case.
In geothermal heat, the outdoor unit is replaced by a heat well or collection circuit that can be placed in the ground or water. Heat is obtained more evenly from the collection circuit or heat well all year round.
With a heat pump, the property's total energy demand does not decrease, but the heat production is enhanced, based on the efficiency ratio, i.e. the so-called to the SCOP value. The SCOP value indicates how many kilowatts of heat can be produced with one kilowatt of electricity.
The part of the air heat pump and air-water heat pump that is placed outside the building is the outdoor unit, which uses the heat energy obtained from the air for the refrigerant. The process works because even in the cold outside air there is thermal energy that can be used. In geothermal heat, there is refrigerant only in the machine of the indoor unit of the geothermal heat pump, such as in refrigerators. Instead, antifreeze circulates in the borehole or collection circuit, from which the heat is further transferred to the refrigerant. Geothermal circuits use environmentally friendly antifreeze.
How do I choose a suitable heat pump?
- There are many types of heat pumps. The site, the site's heat distribution method and the resident's needs determine whether air, air-water, or geothermal heat is suitable for him. So it doesn't matter what kind of heat pump you choose. A professional can best help in the selection.
- The property's heat distribution (floor heating, radiator heating, etc..) has a very large effect on the choice of heat pump, as well as on the efficiency of the heat pump. Whether we want 35-degree water or 60-degree water in the heating network has a significant impact on the energy savings achieved with the heat pump.
- Ground source heat pump and Air-to-water heat pump are the actual heat sources of the house. In new production, they are currently the two most popular forms of heating. In renovation sites, a geothermal heat pump or air-to-water heat pump is installed to replace an existing heating device, e.g. a wood, chip, oil, pellet or natural gas boiler, electric or district heating device.
Heat pump installation
Installation of all heat pumps is always the work of a professional, whether it is an air, air-to-water, or geothermal heat pump. Professionals know how to dimension the equipment correctly and choose the optimal location so that the heat distribution is as efficient as possible. In Finland, professional qualifications are supervised and awarded by the Center for Security Technology, i.e. Tukes.
How do I choose a suitable air source heat pump?
- The mutual differences between air heat pumps are small, and the most significant differences are the size and power variability between different models. The most important thing in dimensioning is to find the right size pump for the space to be cooled or heated.
- The openness of the premises, the ventilation of the apartment, the location of the outdoor unit and the energy class of the house also affect the selection of an air source heat pump.
- All air source heat pumps have a filter that collects the dust particles floating in the indoor air, and many have reported that the quality of the room air has improved immediately after purchasing the pump. Because of this, the air heat pump is also very good for households with pets or homes with allergies. The filter must be cleaned approximately every two weeks by vacuuming or washing. The plasma filters in high-quality air heat pumps remove, for example, odors and pollen from the air.
- Remote control is an almost indispensable piece of equipment for both cottage and home use. Remotely operated heat pumps save time and money significantly. Faults can be accessed remotely and errors can be fixed remotely.
- Maintenance heat refers to a temperature of about 16 degrees, with which the cabin stays at a suitable temperature all year round, even when empty, without needlessly consuming energy. With remote control, you can heat the cabin via the Internet.
Indoor unit
It is recommended to place the indoor unit in a central place, from where the air flows evenly and unhindered to different parts of the apartment. Since the indoor unit blows air downwards, it should be placed close to the ceiling line. Many people place the indoor unit over a doorway, for example. It is good to choose the location of the indoor unit first, as it is the most visible part of the air source heat pump for the residents. When using cooling, it is good to remember that the air heat pump only cools the air downwards from the indoor unit. In a two-story house, a pump installed in the stairwell at the level of the mezzanine cools the lower floor, but not the upper floor. Many people have had to learn this so-called "the hard way".
Outdoor unit no more than 15 meters away from the indoor unit
Since the location of the indoor unit is often chosen first, the location of the outdoor unit is determined based on that. The maximum length of the refrigerant piping is theoretically 15 meters, so the outdoor unit cannot be placed further than this from the indoor unit. However, it is good to note that it further improves the efficiency, the shorter the pipe length can be. The most optimal situation is when the pipe length between the indoor unit and the outdoor unit can be kept below five meters. In the placement of the outdoor unit, air directions or solar radiation are of little importance. It is recommended to place the outdoor unit close to the ground, but above the snow line, as condensation usually drains from the unit. The outdoor unit should be monitored from time to time to ensure that it does not accumulate, for example, ice in winter or tree leaves in autumn, etc.
Remember these when choosing an air source heat pump:
- Make sure that there is a suitable central and spacious place for the indoor unit in the apartment. Sometimes it is necessary to make small changes in the interior in order to get a suitable space for the indoor unit. Even if at first the pump is a new acquaintance, we have found that once the heat pump has become a part of our customer's everyday life, he will never want to give it up.
- Choose a professional with a lot of experience, high-quality products, and a good maintenance guarantee as the supplier and installer of the device. Ask the seller and installer of the device for calculations of savings and detailed information about the features of the device. At the same time, you will test the expertise and familiarity of the supplier of the device.
Kalle Lyytikäinen
managing director