Comparison Daikin VKM100GBM vs Daikin VKM100GB

Additional functions provided in the design of the unit in addition to ventilation.

— Recuperator. A heat exchanger that prevents "blowing" heat from the room during the cold season. The principle of operation of the heat exchanger is that it takes energy from the blown air and transfers it to the incoming one — thus, ventilation sends relatively cool air out and supplies preheated air into the room. The use of a heat exchanger can significantly reduce heat loss and, accordingly, heating costs — the amount of heat returned in the most advanced heat exchangers can reach 97% (see "Heat exchanger efficiency"). At the same time, such systems are often passive and do not themselves consume energy (and where it is required, the consumption is still lower than the amount of saved heat). Naturally, this function is found only in full-size, supply and exhaust units (see "Type of ventilation"). Note that external recuperators are also produced, which can be supplemented with ventilation units that do not have this function; however, an integrated heat exchanger is often more convenient and efficient.

— Heater. The built-in heater intended for heating the air coming into the room. At the same time, in contrast to the heat exchanger described above, energy is used...for heating from a third-party source — an electric heater or a water heat exchanger (see "Heater type"). This method of heating requires additional energy costs, and water circuits are also quite troublesome to connect. But it is much more efficient: if the air supplied from the heat exchanger into the room cannot be warmer than the air blown out, then this is not a problem for the heater. This function is mainly used to raise the temperature of the supply air supplied from the heat exchanger (built-in or separate) to the temperature of the extract air and thus avoid unnecessary heat losses.

— Cooler. A built-in system that reduces the temperature of the air supplied to the room. Simplified, this function can be called a "built-in air conditioner" — because air conditioners are usually used to cool the air in hot weather. In fact, in some cases, installing an air ventilation unit with a cooler can eliminate the need for separate air conditioners. On the other hand, such systems are quite complex and expensive, and therefore they are used rarely, mainly among centralized units(see "System").

— Humidifier. A system that increases the humidity of the air supplied to the room. The peculiarity of the human body is such that the feeling of a comfortable climate depends not on the absolute, but on the relative humidity of the surrounding air. Relative humidity, on the other hand, depends not only on the actual amount of water vapour in the air but also on temperature: physical laws are such that as the temperature rises, relative humidity drops, even though the amount of moisture in the air remains unchanged. In fact, this leads to the fact that during the cold season, the heated outside air begins to seem dry. To avoid this effect in climate technology, including air ventilation units, humidification systems may be provided. Note that such systems usually require either a connection to the water supply system or regular refilling of the water tank.

— Ionizer. A system that saturates the air entering the room with negatively charged ions. The effect of such ions on the climate is positive — the air feels fresher, ionization contributes to the sedimentation of contaminants on the floor and walls and provides a bactericidal effect. In addition, it is believed that ionized air is good for health, improves immunity and recovers from injuries and illnesses.

The noise level produced by the air ventilation unit in normal operation.

This parameter is indicated in decibels, while the decibel is a non-linear unit: for example, a 10 dB increase gives a 100 times increase in sound pressure level. Therefore, it is best to evaluate the actual noise level using special tables.

The quietest modern ventilation units produce about 27–30 dB — this is comparable to the ticking of a wall clock and allows you to use such equipment without restrictions even in residential premises (this noise does not exceed the relevant sanitary standards). 40dB is the daytime noise limit for residential areas, comparable to average speech volume. 55–60 dB — the norm for offices, corresponds to the level of loud speech or sound background on a secondary city street without heavy traffic. And in the loudest, they give out 75–80 dB, which is comparable to a loud scream or the noise of a truck engine. There are also more detailed comparison tables.

When choosing according to the noise level, it should be taken into account that the noise from the air movement through the ducts can be added to the noise of the ventilation unit itself. This is especially true for centralized systems (see "System"), where the length of the ducts can be significant.

Static pressure created by the air handling unit at the inlet.

This parameter is required for calculations related to the selection of the installation for a ventilation system with long air ducts. The static pressure must be equal to the resistance of the duct network at a given air flow. More detailed information about this parameter and its application can be found in special sources.