Hybrid ventilation free-cooling simulation in Energy Plus. Application on ashopping center retrofitting, in Portugal.

Buildings take a great share on the total energyconsumption and C02 emissions in Portugal.Poorly thought buildings pollute the urbanspace, and contribute to the increasing buildingssector energy demand. When thinking inretrofitting old buildings, the common thoughtis that huge amounts of money must be spent onit. This paper, presents a case study on a poorlyenergy performing commercial building, wherea hybrid ventilation free-cooling technique isused to demonstrate its potentiality to efficientlydecrease building energy consumption, withoutrequiring huge investments. The originalbuilding configuration, without free-cooling,originates high inside temperatures throughoutthe year. The energy needed for space coolingrepresents 48% of total building annualconsumption.Generally, results show that hybridventilation free-cooling, using the coldmountain air at nighttime has a great potentialfor reducing energy consumption, of the orderof 10% of total building climatization energydemand. Sensitivity analysis providedparametric knowledge about the performance ofthe technique when applied to this buildingunder different conditions. A reduction of142 tC02/year, in the total building Carbonemission is estimated.