Many people dread the sort of summer heat waves that we have seen over the past few years. This has encouraged professionals to develop solutions to ensure thermal comfort in our homes. They draw on two processes that we tend to confuse: cooling and air conditioning. In reality, they have very different features. What are they?
Air conditioning: an overall solution for home comfort
Air conditioning is a technique that consists of changing, controlling and regulating the climatic conditions (temperature, humidity, dust level, etc.) in a home or workplace. It aims to ensure favourable conditions for occupants all year round.
The air-conditioning process usually incorporates different features:
- Air quality: treating dust by filtering the air it supplies or recirculates.
- Air temperature: changed according to the season.
- Hygrometry: the ambient humidity controlled by humidifying and dehumidifying the air.
- Air speed.
- The noise level of the installation.
Air-conditioning systems enable the temperature of a room to be lowered by 6 to 8°C. However, it is advisable not to create a difference of more than 7°C between the temperature inside and outside an area (particularly because this can cause colds). There are two types of system:
- Direct expansion systems, which use liquid refrigerant as heat-transfer liquid, to transfer heat from air-conditioned rooms to the outside.
- Chilled-water systems, which use water to transport cool air around the building. For chilled-water systems, a network of multi-layer or carbon steel pipes is particularly suitable.
Because they involve energy consumption in summer, air conditioning systems are considered to be energy-intensive, and French regulations impose various restrictions on their use.
Cooling: a solution that is still not sufficiently well-known
Cooling consists of lowering the temperature of a living space or workplace to obtain an optimum temperature for comfort or use. This concept is consistent with an energy saving approach and features in the French Thermal Regulation 2012 (RT2012). Indeed, cooling does not necessarily require energy-intensive equipment to achieve a good level of thermal comfort in homes. Nevertheless, the resulting drop in temperature does not usually exceed a difference of 3 to 4°C in relation to the original temperature. Furthermore, the cooling process does not take into account the humidity and quality of the air.
Cooling is often offered as an option as part of a heating system. In many cases, it uses the same emitters as those used for heating, simply requiring the installation of a reversible heat pump. This is the case with certain active radiators or underfloor heating. With an underfloor heating installation, you just need to ensure that the control system is reversible and that the manifold is also adapted to this reversibility, so that the floor can be used for cooling.
In many cases, a cooling system is sufficient to bring comfort in summer, without having to resort to installing an expensive air-conditioning system.
The cooling process is still less well-known than air conditioning, which remains the most popular method when it comes to ensuring thermal comfort in summer. However, as it can lower the original temperature of an area (living or workspace) by 3 to 4°C, cooling is effective and can be used as a simple option as part of a heating system, particularly in the case of underfloor heating.