Cometres, a simple tool for the improvement of summer comfort in residential buildings.

In summer, it is possible to achieve a satisfactory comfort in residential buildings with purely passive means as thermal inertia, possibility of cross ventilation and solar protection of the external envelope. These parameters have to be taken into account at the earliest stages of building design. Because the maximum cooling power is generally available at night and the maximum temperature occurs in the middle of the day, the calculation tools must take into account in a quite accurate way the non steady state thermal behaviour of the rooms, and the control strategies must compensate this phase displacement, while keeping the indoor climate comfortable during occupancy. We developed, on the basis on a simple RC equivalent network, a thermal dynamic model with a particular attention paid to the impact of the outdoor noise. This model, called COMETres, follows validation procedure of the TC89WG6 of the European Comity of Normalisation (CEN) which works on thermal performance of buildings in summer without mechanical cooling (prEN 13792). This simplified reference calculation method enables to calculate the indoor temperature profile for a reference warm day according to a zoning of metropolitan French territory. Used primarily for new buildings, this tool will be also be a help for retrofitting.