Measured Energy Savings from the Application of Reflective Roofs in 3 AT&T Regeneration Buildings.

摘要

Energy use and environmental parameters were monitored in three AT&T regeneration buildings during the summer of 2000. These buildings are constructed with concrete and are about 14.9 m2 in size (160 ft2; 10x16 ft). The buildings were initially monitored for about 1 1/2 months to establish a base condition. Then, the roofs of the buildings were painted with a white coating and the monitoring was continued. The original roof reflectances were about 26%; after the application of roof coatings the reflectivities increased to about 72%. In two of these buildings, we monitored savings of about 0.5kWh per day (30 Wh/m2 per day (3 Wh/ft2)). The third building showed a reduction in air-conditioning energy use of about 13kWh per day (860 Wh/m2 (80 Wh/ft2)). These savings probably resulted from the differences in the performance (EER) of the two dissimilar AC units in this building. The estimated annual savings for two of the buildings are about 125kWh per year (8.6 kWh/m2 (0.8 kWh/ft2)); at a cost of $0.1/kWh, savings are about $12.5 per year. Obviously, it costs significantly more than this amount to coat the roofs with reflective coating, particularly because of the remote locations of these buildings. However, since the prefabricated roofs are already painted green at the factory, painting them with white (reflective) color would bring no additional cost. Hence the payback time for having reflective roofs is nil, and the reflective roofs save an accumulated 3750 kWh over 30 years of the life of the roof.