By enabling efficient heat transfer from the district heating network to residential and commercial buildings, the heat exchanger plays a key role when we want to use heat supplied by the municipal heating system. However, few people have extensive experience in this area, and when connecting a house to the municipal network, many questions arise, such as how to choose the right heat exchanger, which is indispensable here. We will try to address the most important aspects and answer the key questions, including: how to select a heat exchanger for the municipal network.
✅ A heat exchanger for district heating is an essential component without which connecting a house to the municipal heating network would not be possible. Its main task is to transfer thermal energy from the municipal network to residential and commercial buildings. Simply put, it acts as an intermediary that ensures safe and efficient heat delivery. Thanks to its thoughtful design and simple operating principle, the heat exchanger forms the foundation of this solution. The heat exchange (more precisely, the transfer of heat from the municipal network to our heating system) occurs automatically. The device uses basic physical principles, is not electrical, and operates independently.
A plate heat exchanger for the municipal network operates on the principle of transferring thermal energy between two media that do not come into direct contact – meaning they do not mix. This minimizes heat loss and increases the energy efficiency of the entire system. It is hard to imagine hot medium from the district heating network directly entering our radiators or underfloor heating (UFH), and then visiting other houses in the city. This would be technically unfeasible due to the expected rapid pressure losses in the municipal circuits. Hence, a plate heat exchanger that only has thermal contact and extracts only thermal energy from the hot medium of the municipal heating network – is indispensable and required.
There is a certain range of heat exchangers available on the market – various types exist. However, plate heat exchangers are used in municipal heating systems. They enable high energy efficiency at relatively lower costs and smaller dimensions. Using other heat exchangers – such as tubular ones – is possible, but not necessarily cost-effective and takes up more space in the boiler room. Therefore, plate models have gradually replaced older types.
Each of these types has specific features that make it suitable for different operating conditions and system requirements.
✅ Plate heat exchangers are among the most popular devices used in connecting houses, apartments, or blocks to municipal heating systems. Their construction is based on a set of thin plates that enable efficient heat exchange between two media while preventing them from mixing. Thanks to their compact design, they offer a large heat exchange surface – which seems to be their greatest advantage.
It can be argued that the production of plate heat exchangers, which were first patented before World War II, paved the way for the widespread development of district heating in Europe and worldwide. Without an easy-to-produce, efficient, and relatively inexpensive heat exchanger variant – the rapid development of municipal heating networks after World War II would have been much slower, as connecting additional houses and public utility buildings would have been more expensive and challenging.
Insulation of the heat exchanger plays a crucial role in reducing energy losses in municipal heating systems. Thanks to it, losses emitted by the heat exchanger in the boiler room are minimized – and almost all energy from the heating plant reaches our central heating system.
Modern insulating materials, such as polypropylene foams, significantly reduce heat loss. This not only saves money for users but also contributes to sustainable development. Every saved kilowatt-hour means less environmental impact and greater care for our planet – although most of us are probably more convinced by the money saved.
Selecting the appropriate heat exchanger when connecting a house, apartment, or service building to district heating is crucial because choosing one that is too small will result in an underheated home. Too small a plate surface area would mean that the amount of heat transferred is insufficient.
In the past, heating plants supplied very hot medium – which in freezing months reached temperatures of up to 100-110 degrees Celsius. Such a hot medium meant that heat exchangers could be quite small, as such a supply always ensured that we had 60-70 degrees in our radiators. Today, things are different. An increasing percentage of thermal energy produced in heating plants comes from low-temperature systems, such as solar heating, electric heating, or cogeneration technology. Additionally, houses have lower demand – building thermomodernization is ongoing, many are already insulated, and many residents have switched to underfloor heating or low-temperature radiators. As a result, heating plants supply much cooler medium, often in the range of 65-80 degrees. This means that the heat exchanger should be slightly oversized – carefully selected to ensure everything works as it should.
✅☑️ The primary factor in selection is the ratio of plate surface area to the house's surface area.
When deciding on a heat exchanger, several key aspects should be considered:
The size of the heat exchanger connections is, of course, very important, but it is impossible to specify what a particular house needs. The issue should be consulted with a specialist (after inspecting the house) – specifically, a plumber who will ultimately perform the connection. They should determine the connection size based on an inspection of the central heating system. In single-family homes, it is most often 1 inch, in small new-build houses sometimes 3/4", but in houses with older heating systems, even 5/4" connections may appear.
No. Generally, proper selection always involves some oversizing, which is beneficial – unlike an undersized heat exchanger. Technically, there are no contraindications to using a larger heat exchanger when connecting a building to the heating plant – in fact, there is a benefit. It lies in the fact that a larger heat exchanger potentially has a longer lifespan without a noticeable drop in efficiency. Heat exchangers, like any device, age over time, experiencing a linear decline in efficiency (due to the accumulation of dirt and deposits on the plates). A larger device, i.e., a model with some plate reserve, ensures that the efficiency drop becomes noticeable much later.
✅ No, this is a myth. As mentioned, a properly selected heat exchanger must be slightly oversized, meaning a bit larger. A heated house where radiators are turned down has the characteristic that the water returning to the heat exchanger (which should absorb heat from the heating network) – remains hot. In this case, it essentially stops absorbing heat significantly. As a result, the actual heat consumption is not higher.
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