Summer Bypass
Both the Brink Renovent Excellent 300 and 400 heat recovery units are fitted with a summer bypass
facility (it is not fitted in the Compact 180 heat recovery unit).
Summer Bypass is a way of introducing cool air, usually at night, after a hot day.
In normal conditions it is not necessary, but a period of hot weather can lead to a build up of heat in
the building, which usually accumulates at the top of the building. It is then desirable to supply
cooler air from the outside which hasn’t been warmed by the heat exchanger. In this instance, the
bypass damper opens when the interior air temperature exceeds a preset temperature (normally
22 °C but this is adjustable) and the exterior air temperature is warmer than a preset minimum of
10 °C (also adjustable) but cooler than the extracted air.
If the outside temperature is higher than the interior temperature (i.e. the extracted air) then the
bypass will remain closed as the extracted air will tend to cool the incoming warmer air, although this
will gradually result in an increase in the internal temperature. This assumes that this is happening on
a hot sunny day, but at night, the outside temperature will drop and as soon as the temperature of
the outside air falls below that of the interior temperature (i.e. the extracted air), then the bypass
opens to let in the cooler air without it going through the heat exchanger.
It will do this until the interior temperature has reached a comfortable level again when it will revert
to normal operation.
For maximum benefit, the inlet and supply ducting should be well insulated.
This makes it possible to supply cooler, fresh air from the exterior that does not pass through the heat
exchanger so it is not warmed by the extracted air. Fresh air supplied through the bypass is still
filtered, so maintaining the air quality, irrespective of the bypass setting.
Whilst the bypass has some
beneficial effects, it should not be relied upon as a method for cooling the building.
The operation of the bypass valve can be adjusted in the settings menu (see chapter 13 of the Brink
Installation manual).
