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.
Heat exchanger efficiency
Efficiency of the heat exchanger used in the heat exchanger of the supply and exhaust system (see "Features").
Efficiency is defined as the ratio of useful work to the energy expended. In this case, this parameter indicates how much heat taken from the exhaust air, the heat exchanger transfers to the supply air. The efficiency is calculated by the ratio between the temperature differences: you need to determine the difference between the outdoor air and the supply air after the heat exchanger, the difference between the outdoor and exhaust air, and divide the first number by the second. For example, if at an outside temperature of 0 °С, the temperature in the room is 25 °С, and the heat exchanger produces air with a temperature of 20 °С, then the efficiency of the heat exchanger will be (25 – 0)/(20 – 0)= 25/20 = 80%. Accordingly, knowing the efficiency, it is possible to estimate the temperature at the outlet of the heat exchanger: the temperature difference between the inside and outside must be multiplied by the efficiency and then the resulting number is added to the outside temperature. For example, for the same 80% at an outdoor temperature of -10 °C and an internal temperature of 20 °C, the inflow temperature after the heat exchanger will be (20 – -10)*0.8 + -10 = 30*0.8– 10 = 24 – 10 = 14 °C.
The higher the efficiency, the more heat will be returned to the room and the more savings on heating will be. At the same time, a highly efficient heat e...xchanger is usually expensive. Also note that the efficiency may vary slightly for certain values of the external and internal temperatures, while manufacturers tend to indicate the maximum value of this parameter — accordingly, in fact, it may turn out to be lower than the claimed one.
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.
Power consumption in ventilation mode
The electrical power consumed by the supply and exhaust unit in normal operating mode (for models with adjustable performance — at maximum speed) can help determine the connection requirements for the unit and estimate the cost of operation in terms of electricity bills. It should be noted that for models with an electric reheater (see "Reheater type"), this refers only to the power of the ventilation system, while the power of the reheater is provided separately (see above). Therefore, the total energy consumption during full operation will correspond to the sum of these power values.
The power consumption can also be used to some extent to assess the unit's performance: "power-hungry" units usually provide a corresponding airflow.
