CO₂ carbon dioxide sensor
A built-in sensor that determines the content of carbon dioxide in the room.
The CO₂ carbon dioxide sensor controls the operation of ventilation and performs two functions at once: it prevents a critical increase in the level of carbon dioxide in the air and at the same time provides energy savings. Recall that carbon dioxide is emitted by people when they breathe, and its high content in the air leads to a deterioration in well-being and even serious health problems. Thus, if the sensor detects an increased concentration of CO2, it increases the intensity of ventilation, providing an additional supply of fresh air. When the concentration of carbon dioxide drops, the intensity of work decreases (up to a complete shutdown if there are no people in the room and the CO2 content does not change); this avoids unnecessary electricity consumption.
Maximum noise level
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.
External static pressure
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.
Minimum operating temperature
The lowest outdoor air temperature at which the ventilation unit can be safely used; more precisely, the minimum inlet air temperature at which the unit can operate normally, without malfunctions, for an indefinitely long time.
It is worth choosing according to this parameter taking into account the climate in which it is planned to use the unit: the device should normally tolerate at least the average winter temperature, and it is best to have some reserve in case of a harsh winter. However, many modern models allow operation at -10 °C and below, and in the most cold-resistant ones, the temperature minimum can reach -35 °C. So choosing a unit for a temperate climate is usually not a problem. Also note that if an installation that is ideally suited for all other parameters cannot cope with low temperatures, the situation can be corrected by using an additional heater at the inlet of the ventilation system.
Note that if the minimum temperature is not indicated in the characteristics, it is best to proceed from the fact that this model requires a temperature not lower than 0 °C. In other words, in cold weather, it is worth using only the equipment for which this possibility is directly stated.
Remote control
The presence
of a remote control in the delivery set of the air ventilation unit.
This configuration is provided in most decentralized models (see "System"). However, it is often found in centralized ones. The possibility of a remote control provides additional convenience for the user — you do not need to approach the unit every time. In addition, many control functions can be transferred to the remote control, making the installation itself more compact (this is true for the mentioned decentralized equipment, which has a rather small size).
Note that the remote control can be both portable and wall-mounted, designed to be permanently in one place (like a wall light switch).
EC fan
The presence
of an EC fan(fans) in the design of the air handling unit.
This term refers to fans with synchronous brushless motors, also known as EC motors. Such motors are more advanced than traditional asynchronous ones: in particular, they provide very uniform rotation, allow precise control of speed, have high efficiency, and generate almost no heat (which is extremely important in the presence of a cooler, see "Features"), and also efficiently operate over a wide temperature range. In addition, the noise level of such motors is noticeably lower, and the service life is longer. The main disadvantage of EC fans is the traditionally high price.
