The engineering services strategy developed by XCO2 for the Family Visitor Centre of Wormwood Scrubs prison in Hammersmith was focused on improving the environmental performance of the building to enhance daylight, thermal comfort, efficiency and end user comfort.

Key to achieving comfort and efficiency was the combination of natural and mechanical ventilation strategies, including a supply and extract system with heat recovery. Main spaces, such as a large flexizone are naturally ventilated, with manually openable low level windows and actuators operating high level clerestory windows that allow warm air to extract naturally.

The natural ventilation system is controlled via an independent system with a combination of temperature sensors and CO2 sensors set to open the high level ventilation when the internal CO2 concentration exceeds 1350ppm. The internal and external temperature sensors open high level vents if the internal temperatures exceed 24oC.

Space and hot water heating is provided via a high efficiency gas boiler that feeds into the calorifier, air handling unit heating coil and an underfloor heating system. The underfloor heating works primarily via radiation producing very subtle stratification and ensuring heat loss is very close to the heat delivered to maintain comfort levels. A rainwater harvesting system provides water for flushing WCs in order to reduce the potable water demands of the building.