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The current study uses a new methodology where the assessment of building cooling demand savings is obtained through a redefined concept of the Climatic Cooling Potential (CCP). This concept allows for the direct estimation of energy savings in buildings by the use of different passive cooling systems at a large spatiotemporal scale. In this paper, we apply this method to assess the impact of climate change on the future potential of Direct Ventilation and Evaporative Cooling. To do so, a set of high resolution climate simulations for the Iberian Peninsula for present and future climate, performed using the Weather Research and Forecasting model (WRF), were used. Three passive cooling simulations were conducted: the first one employs the hindcast simulation where WRF is forced by the reanalysis ERA-Interim for the 1989–1999 period (hindcast); the second employs the EC-EARTH forced historical run ranging from 1970 to 2000 (historical) and the third also forced EC-EARTH but for 2070–2100 (future). An eleven-year period was extracted from the historical run and validated against the first, the hindcast. The similitude of the results provided confidence on the ability of the EC-EARTH forced runs to correctly simulate climate and thus allowing the assessment of the effect of climate change in the outcome of the passive systems and cooling demand savings in buildings. The results show that the CCP conserves its spatial heterogeneity for both historical and future, but presents lower values for the future due to the increase in temperatures. Nevertheless, this reduction is mostly below 20% over the entire Iberian Peninsula along the annual cycle, for both Direct Ventilation and Evaporative Cooling. This means that even in the context of a changing climate, these kind of systems can still offer valuable reductions on the cooling demand of buildings. Furthermore, most of the reductions in the CCP, caused by the increase in temperatures, can be surpassed by increasing the flow rate or can even be compensated by the increase in Cooling Demand as a consequence of the rising temperatures. [ABSTRACT FROM AUTHOR]

In the present study a new methodology allowing the assessment of building's cooling demand savings by the use of ventilated passive cooling systems is presented in a twofold innovative way. Firstly, using a redefined concept of the climatic cooling potential (CCP), which allows for the direct estimation of savings in building's cooling demand by the use of different passive cooling systems on a large spatiotemporal scale. Secondly, this assessment relies on high resolution climate dataset built using a regional climate model covering the Iberian Peninsula (IP) with a 9 km horizontal spacing and the period between 1989 and 2008. Here, the CCP concept is applied for direct ventilation and evaporative cooling, in such a way that it allows for a comparison with the building monthly cooling demand, providing a direct assessment on the cooling demand savings for any building, for three air flow rates. The results show that CCP is asymmetrically distributed both spatially and temporally within the IP. During the cooling season CCP values are above 1 kWh per m 3 of building and 3 kWh per m 3 of building, for direct ventilation and evaporative cooling, respectively. Evaporative cooling provides a less heterogeneous annual cycle of CCP than direct ventilation, with a relative difference in the south and central part of the Iberian Peninsula superior to 100% during summer. Nonetheless, despite the consistently higher values offered by evaporative cooling, in the coastal regions the relative difference between the two systems drops to less than 10% due to the higher moisture in the air. For the case of a typical office room in the region of Lisbon, in the month of August, the cooling demand savings provided by the use of direct ventilation and evaporative cooling can represent more than 27% and 40% of the cooling demand, respectively. [ABSTRACT FROM AUTHOR]

The objective of this article is to develop and test a simplified method to compute the savings in building cooling demand by use of passive cooling systems based on ventilation (direct night ventilation, air–soil heat exchangers, controlled thermal phase-shifting, evaporative cooling, as well as possible combinations thereof). The systems are characterized in terms of a climatic cooling potential, independently of any building, which is then compared to the cooling load of a particular building. The method is tested against an extensive numerical simulation campaign, combining diverse passive cooling systems and sizes with diverse constructive and operational modes for an administrative building situated in Geneva. The key point of the simplified method is to choose an appropriate time resolution, for taking into account the building thermal inertia. Although best results are obtained with a daily resolution, good results are also obtained with monthly data, where an overestimation of the passive cooling fraction remains less than 20% in half of the cases. This opens way for using the method for first assessing the potential of these passive cooling techniques on a large spatiotemporal scale, for which integrated building and system simulation becomes prohibitive. [ABSTRACT FROM AUTHOR]