Renewable ventilative cooling? Insights from an Irish perspective

The future needs of indoor spaces in our buildings are likely to be cooling focused. With the widespread use of air-conditioning (AC) on the horizon there is now a need to ensure our systems perform as renewables (under the relevant definitions). A key part of tackling the uptake in energy intensive AC is likely to be the balancing of AC with renewable natural and mechanical ventilative cooling (VC). It is evident that a total reliance on AC could have significant ramifications for any building sector emissions targets but could also leave building occupants vulnerable to power outages from increased pressure on electricity grids. It is therefore critical that existing design practices encourage the use of passive systems, which take advantage of natural and renewable sources of energy be they as primary, supplementary, or secondary cooling systems or featured as part of a hybrid cooling system. To address this, the aim of this work was to determine the potential renewable energy contribution that natural ventilative cooling systems (NVCs) or mechanical ventilative cooling systems (MVCs) can have under favourable conditions in a temperate climate. Three different stages to this evaluation are presented: 1) a cooling demand using cooling degree hour (CDH) analysis in current and future conditions, 2) a simplified design stage evaluation of the potential of single-sided NVC and MVC, and 3) a calculation of the seasonal performance factor for NVC and MVC systems. In addition to this, the potential for NVC is discussed in relation to the existing building stock in Ireland. Initial results indicate that the NVC potential in supply terms is currently outstripping demand by greater than 3.5 times. Current calculations for NVC and MVC renewable status show a strong basis for their consideration in future, but more detail is required. The results also indicate that NVC and MVC systems are likely to be a renewable source that is currently not officially accounted for.