Peak power and cooling energy savings of high-albedo roofs

In the summers of 1991 and 1992, we monitored peak power and cooling energy savings from high-albedo coatings at one house and two school bungalows in Sacramento, California. We collected data on air-conditioning electricity use, indoor and outdoor temperatures and humidities, roof and ceiling surface temperatures, inside and outside wall temperatures, insolation, and wind speed and direction. Applying a high-albedo coating to one house resulted in seasonal savings of 2.2 kWh/d (80% of base case use), and peak demand reductions of 0.6 kW. In the school bungalows, cooling energy was reduced 3.1 kWh/d (35% of base case use), and peak demand by 0.6 kW. The buildings were modeled with the DOE-2.1E program. The simulation results underestimate the cooling energy savings and peak power reductions by as much as twofold.