Design Solution · HVAC & Energy
Design Solution · Dream about it
Overnight purge of exposed mass provides daytime cooling.
Exposed heavy structure is cooled overnight by purging cool night air, then absorbs heat through the following day acting as a passive heat sink. Dynamic thermal modelling confirms the spaces meet TM52 and ESFA overheating criteria without active cooling.
Overnight purging of cool night air through a building with exposed concrete or masonry structure charges the thermal mass as a passive heat sink, which then absorbs heat through the occupied day and delays or eliminates the need for active cooling. This is a well-established passive cooling strategy, and the record strengthens the claim slightly by citing TM52 and ESFA overheating compliance verified through dynamic thermal modelling — that is a more substantive assurance than a bare assertion, though it is modelling evidence rather than post-occupancy verification. The conditions for the strategy to perform are specific: the building needs exposed thermal mass (false ceilings undermine it), reliable overnight temperature differentials between exterior and slab (diminishing under future climate projections), and controllable openings that can be secured against security and weather risk. Climate change is the long-run risk to plan around — the strategy relies on cool nights, which become less frequent under warming scenarios, and a design that performs today may need to be supplemented with active cooling in future decades, so the HVAC installation should be scoped with that possibility in mind.
#thermal mass #night purge #passive cooling