These work by heating a boundary layer of air, typically less than 5mm thick, on the external surface of a pre-finished steel collector which is fixed to a southerly wall elevation. This boundary layer is drawn through micro-perforations in the collector into a cavity and at its simplest then circulated through a building using a fan.
The transpired solar collector is installed as an additional micro perforated pre-finished steel skin onto an existing (or new) structurally sound wall (metal and non-metal), creating a cavity between the wall and the metal skin.
Negative air pressure created within the cavity by a ventilation fan draws ambient outside air through the micro perforations in the transpired solar collector’s surface. This outside air is then heated as it passes through the perforations and collected within the cavity. Fresh heated air from the cavity is then fed either directly into the building as ventilation air (industrial applications), or ducted into a HVAC unit (commercial & residential applications), where it is used as a pre-heater to the main heating system.
A transpired solar collector can collect around 50% of the energy falling on its surface which equates to approximately 500wp/m2 of the collector’s surface area and can deliver around 250KWH/m2 per year or up to 50% of space heating requirements depending on building configuration and usage.
Application on SBEC building
The Colorcoat Prisma® Anthracite solar collector installed in front of the bay area, feeds large volumes of pre-heated air into the prototyping bay, reducing the need for non-renewable heat sources. Depending on the incident solar radiation and the temperature internally and externally, the incoming air from the transpired solar collector can either be fed directly into the building or be boosted by natural gas to maintain a comfortable internal environment.
For part of the building the Colorcoat Prisma® cassette façade solar collector in Linden Green (specifically designed for commercial applications) provides pre-heated make up ventilation air to air handling units used to distribute the heated fresh air internally. When necessary incoming air temperature can be boosted by the heat pump but this demand is expected to be low due to the heat recovery system (of expelled air) in place.
The Linden Green cassette façade solar collector in the other part of the building works in the same way but the heating/cooling load is shared between ventilation air and contact heating from under floor systems.