The IIR has just published a new Informatory Note on passive cooling prepared by Renato Lazzarin, President of IIR Section E on Air conditioning, heat pumps and energy recovery.
Passive cooling concerns different applications including the prevention and reduction of heat gains, and heat dissipation. Heat dissipation technology aims to exchange the excess heat between a building and a lower temperature sink such as the sky, the ground, the water, or the ambient air.
Passive cooling technologies can contribute significantly to reducing energy demand for air conditioning. The potential advantages are strongly bound to local conditions which need to be carefully considered by designers.
Characteristics of the ground, availability of aquifers, daily variations in ambient temperature all year long and air humidity levels are some of the parameters to be evaluated after the implementation of heat gain prevention and reduction measures.
Under the most favourable conditions, passive cooling can completely fulfil the cooling demand of a building, possibly assisted by appropriate cold storage through the concurrent use of several technologies. Such an approach is made possible by integrated building design.
However, even where the possible contribution is only marginal, hybrid systems can be designed by coupling one or more passive technologies with conventional cooling technologies, allowing significant energy savings.
The note also includes a series of recommendations aimed at developing passive cooling:
- A thermal coupling between the building and the sink.
- The heat dissipation processes that are considered.
- Coupling of the room to be cooled with the ground or an aquifer.
- Night ventilation cooling.
- Radiative cooling towards the sky.
- Evaporative cooling.
A summary for policymakers outlining the main conclusions and recommendations of this Informatory Note is also available at no charge.