D4FC – phase 2
PassivOffices 4 Devon at Devonshire Gate Project
April 2013
Unlike the domestic situation heat gains are predominantly during day from solar gain and in-use 8-20 activities. During unoccupied hours this heat can be purged.
Intelligent Ventilation Control
Passive ventilation strategies rely on external air to help cool the building. If external air temperatures are hotter than inside than this can increase the levels of internal overheating. Rather than cool the building down.
In future climate change scenarios there will be increased incidents of hotter external air temperatures than inside.
cost neutral
Intelligent ventilation control involves ensuring that openings are closed to minimum fresh air levels under this scenario.
This could be done manually via a simple temperature warning system or automatically via temperature sensors, BMS system and actuated opening control.
A MVHR system has already been included in the scheme and this provides an ideal strategy to enable this system when windows close. Coupled with ground cooling or other such cooling elements such as exhaust air heat pump or dessicant wheel will enhance this strategy further.
A mixed mode approach could be adopted whereby the MVHR system is enabled for minimum fresh air volumes and if coupled to ground cooling system would further reduce the effects of overheating.
Daylight Design and Daylight Dimming
Ensuring good daylight design in internal spaces helps reduces lighting loads associated energy consumption and internal gains which increases overheating. The optimum has to be designed when sizing, selecting glazing types and the shape of windows to ensure good daylights levels internally, reducing heat loss in winter, and minimising solar gain during the summer. It can also be beneficial in the whole building energy analysis to optimise solar gain in winter.
Reducing internal gains in office buildings will be a key strategy in ensuring buildings can be passively designed to adapt to future climate change scenarios. Reductions in internal gains can help reduce the reliance on energy intensive air conditioning equipment. And adopt more passive measures.
Reducing internal loads such as from lighting can have a significant impact on overheating levels.
A simple strategy using current technology is to ensure lighting systems are designed to switch off when not required provided adequate daylight levels are being met.
Gale & Snowden Architects
Final Report
cost neutral
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