Cooling with underfloor heating: Energy-efficient alternative to air conditioning
Published: 04.06.2024 | Reading Time: 5 minutes
This text is machine translated.
When temperatures rise in summer, it quickly becomes unbearably hot in offices, apartments and houses. Rooms exposed to direct sunlight are particularly difficult to keep cool. Air conditioning systems and air conditioners are one way of keeping a cool head indoors despite the heat. However, they blow into the room, are not exactly quiet and installation often fails due to local conditions or costs.
Underfloor heating with a heat pump and cooling function makes air conditioning systems superfluous. With heat pump cooling, your rooms are cooled via the water pipes of the heating system. The heating surfaces in the floor or ceiling extract the heat from the indoor air and dissipate it outside. In this way, the heating system can keep work and living spaces warm in winter and provide comfortable, efficient and cost-effective air conditioning in summer.
Natural and economical cooling via underfloor heating helps to prevent heat build-up, improves concentration and increases well-being. Heating and cooling in one system is characterized by lower initial costs and less maintenance. Thanks to its dual function, the heat pump is useful almost all year round and not just in a few summer weeks.
Little electricity is required for cooling, which makes the technology environmentally friendly and keeps your operating costs low. In addition, the heat pump can be easily combined with renewable energy sources such as PV systems. In this way, you sustainably reduce the primary energy consumption and CO2 emissions of your building.
Cooling via the underfloor heating or ceiling heating is stepless, draught-free and without annoying fan noise. The even heat dissipation over a large area keeps the room temperature at a comfortable level everywhere and avoids local cold zones. The gentle supply of cold is advantageous for a pleasant room climate at the workplace and at night for a restful sleep.
As no cooled air swirls around, no dust, pollen or pathogens are spread around the room. This also makes floor cooling interesting for allergy sufferers.
When cooling buildings with heat pumps, the panel heating works like a refrigerator: the low-temperature heating water flows through the pipe system, absorbing the thermal energy from the rooms and heating up in the process. The heat exchanger in the heat pump extracts some of the thermal energy from the water and transports it outside. Brine/water and water/water heat pumps release the extracted heat into the cold ground or groundwater, air/water heat pumps into the outside air.
A positive side effect of geothermal heat pumps is that the energy supplied to the ground via the heat pump air conditioning at the end of the summer period heats the ground, depending on the subsoil. It is available as geothermal energy into the fall for efficient heating via the heat pump.
Active cooling
Active systems work with a reversible heat pump and achieve a high cooling capacity with moderate power consumption. Active cooling uses the compressor in the heat pump. It compresses the heat transfer medium used for heat exchange, the temperature of which rises. This leads to a higher temperature difference and consequently to an active transfer of room heat from the floor circuit. A 4-way valve and a second expansion valve ensure that the flow direction in the refrigerant circuit is switched and hot water is supplied regardless of the operating mode.
Passive cooling
Passive cooling systems work with a pump to circulate water, but without a compressor. In passive cooling or “natural cooling”, the heat pump only uses the natural temperature difference between the indoor air heated in summer and the cooler ground. A 3-way valve, additional hydraulic components and a circulation pump bypass the compressor. Technical complexity and power consumption are lower than with active cooling.
Passive cooling is considered a particularly energy-saving and ecological method of building air conditioning. Compared to active cooling using panel heating or air conditioning, however, the cooling capacity is limited. Passive cooling with underfloor heating requires foresighted planning. Activate the cooling as early as possible to prevent rooms from heating up at higher outside temperatures.
Dew point monitoring is an important aspect of room cooling via underfloor heating. It prevents moisture damage in cooling mode due to condensation on the heating pipes in the building and on floor coverings.
The natural moisture in the air can condense on cooled surfaces and form droplets. To prevent condensation from forming in the first place, the underfloor heating must not cool too deeply. Dew point monitoring takes care of this. It regulates the cooling capacity of the heat pump and the flow temperature in the water circuit so that the temperature does not fall below the dew point.
If the rooms are already equipped with water-powered panel heating in the floors, ceilings or walls, the effort required for cooling is low. Heating systems with water-supplied fan coil units or concrete core temperature control can also be considered as cooling surfaces. Systems with classic radiators are designed for high temperatures in the water circuit and not for comparatively cold water. Radiators are therefore not suitable for room cooling.
Heat pumps with an integrated cooling option as standard have the air conditioning system on board ex works, while a cooling function can often be easily and inexpensively retrofitted to other models. The prerequisite is a suitable water/water, brine/water or air/water heat pump that can be used as a heat sink. No additional installations are required in the rooms to be cooled.
If you are already using a reversible heat pump, it is usually possible to convert it for active and passive cooling. Otherwise, you should consider upgrading to Natural Cooling with passive cooling. Natural Cooling boxes contain all the necessary components and simplify the conversion.
If you are planning a new build or renovation of your heating system, an economical underfloor heating system for heating and cooling is quick and easy to install. We offer systems for residential and commercial buildings as well as industrial floor heating with cooling.