A management device estimates an air temperature inside a data collection apparatus as an estimated air temperature, based on operation data received from an air conditioner and meteorological data received from a server via a communication device. When the estimated air temperature is higher than an operable temperature of the communication device, the management device performs control to decrease the air temperature inside the data collection apparatus. When a ventilation-in-progress air temperature is higher than the operable temperature of the communication device, the management device transmits to a breaker device a command to stop the communication device, thereby decreasing the air temperature inside the data collection apparatus. When the ventilation-in-progress air temperature is lower than or equal to the operable temperature of the communication device, the management device transmits to the breaker device a command to run the ventilation device, thereby decreasing the air temperature inside the data collection apparatus.