The roof is the part of the building most subjected to the solar radiation, so we can work on it. We can use light painting changing albedo to improve the reflection coefficient instead transmission and adsorption coefficient, limiting the heat through the external envelope; or we can use green roof, this type of solution is interesting because the thickness of soil can improve the thermal mass and the thermal insulation of the roof without any type of insulting material, and with the help of the plants can reduce a lot the incident solar radiation, this is due thanks to the leaves that reflect a big part of solar radiation, making a sensation of fresh in the room under the roof; it can create also advantages for rain because ground can adsorb store and gradually release the water instead traditional roofs, that flow all the water rain in the street. Green roof to be efficient require a good maintenance to assure the plants life, and to avoid damage on the substructure.
OTHER STRATEGIES
Another strategies to consider is the thermal mass that can adsorb a good quantity of solar energy during days and release it during night, but in this type of climate is better to consider light envelope with consideration to ventilation respect to the thermal mass. Also using evaporative cooling, it can be not useful in this type of climate due to the very high relative humidity of the air in the external environment.
Saint Petersburg