Reduced air conditioning load and running costs

Night Purge

There is a method to replace indoor heat with outside air at night. This is called "Night Purge." Since the outside temperature is lower at night than during the day in summer, it is also called "nighttime introduction of outside air," "nighttime cooling," or "nighttime ventilation." It is the same as outdoor air cooling in that it uses outside air, but the effect is different.
Peak loads tend to occur when the air conditioning is started, but by actively introducing outside air at night or early in the morning to cool the room, it is possible to shift the start time of the air conditioning the next morning and peak times.

Night purging is used as an air conditioning method in office buildings and large facilities in semi-cold and cold regions, but it is also effective to open ventilation windows at night to perform night purging (introduction of outside air) in some agricultural and production facilities. Cooling the parts of the room that have accumulated heat is important to reduce the air conditioning load. Heat is generated from many devices and lights in the air-conditioned space, and internal heat exists even during the night when there is no sunlight. As long as heat is generated in a closed space, the temperature will gradually rise.

If ventilation is promoted here, the temperature outside is lower than the temperature inside, so outside air can be brought in to cool the room.

Night purge is more effective if it takes in outside air and expels heat at the same time. It moves the air taken in from the interior zone to the perimeter zone. In other words, by hitting the air against the interior side (perimeter zone) of the south and west exterior walls where heat has accumulated during the day and then exhausting it as is, it is possible to cool not only the heated air but also the high temperature exterior walls that have accumulated heat during the day. This can reduce the running costs of the air conditioning.