Heat exchange ventilator

A heat exchange ventilator comprising:

• a casing in which an exhaust air passage through which indoor air is discharged out of a room and a supply air passage through which outdoor air is supplied into the room are independently formed;
• a blower unit including an exhaust blower to generate an exhaust airflow going through the exhaust air passage and an air supply blower to generate a supply airflow going through the supply air passage;
• a heat exchanger to cause heat exchange between the supply airflow and the exhaust airflow;
• a temperature adjustment coil provided downstream of the heat exchanger in the supply air passage to heat or cool supply air that is the outdoor air passing through the supply air passage;
• a supply air temperature measurement unit provided downstream of the temperature adjustment coil in the supply air passage to measure a supply air temperature that is a temperature of the supply air passed through the temperature adjustment coil;
• and
• control circuitry to control operation of the blower unit and the temperature adjustment coil, wherein
• the control circuitry performs blowing temperature moderation control of performing ventilation by controlling operation of at least one of the blower unit and the temperature adjustment coil so as to moderate a blowing temperature of the supply air blown out from the casing, the controlling being based on a result of comparison between a lower limit blowing temperature defining a lower limit of the blowing temperature of the supply air blown out from the casing, an upper limit blowing temperature defining an upper limit of the blowing temperature of the supply air blown out from the casing, and the supply air temperature, and
• the control circuitry is configured to:
• during the heating operation of the temperature adjustment coil, compare the upper limit blowing temperature with the supply air temperature, and change a heating capacity of the temperature adjustment coil to a value selected from a plurality of values on the basis of the comparison between the upper limit blowing temperature and the supply air temperature, the plurality of values including three or more values to be selected, so as to make an amount of heating in the temperature adjustment coil smaller as the supply air temperature is closer to the upper limit blowing temperature;
• and
• during the cooling operation of the temperature adjustment coil, compare the lower limit blowing temperature with the supply air temperature, and change a cooling capacity of the temperature adjustment coil to a value selected from a plurality of values on the basis of the comparison between the lower limit blowing temperature and the supply air temperature, the plurality of values including three or more values to be selected, so as to make an amount of cooling in the temperature adjustment coil smaller as the supply air temperature is closer to the lower limit blowing temperature.