Impact of Solar Reflectance Attenuation and Roof Cleaning on a Cool Roof: Assessing Return on Investment for Facility Management

Abstract

Research has shown roofing systems with high solar reflectance and thermal emissivity lead to less heat absorption, a consequential reduction in cooling load demand, and a resultant reduction on energy expenditure. Studies on energy savings from cool roof coatings have been conducted for decades and when compared to more traditional roofing systems have demonstrated energy savings ranging from 2-40%, with average savings estimated at 20%. The 20% average is widely used by cool roof industry professionals, designers, and contractors to market and sell the technology in the commercial sector to owners and owner representatives researching new roofs. While the 20% energy savings is a documented average, unfortunately there is no average roof. Each roof is unique considering size, materials, and location to name a few. In addition, the ability of the cool roof to maintain the original solar reflectance is integral to realizing energy savings. The case study calculated project payback for a 20-year cool roof design using both 30% and 20% estimated annual energy savings. In addition, building material specifications and solar reflectance attenuation in respect to reductions in cooling energy were projected into the payback calculations. Lastly, the cost impact of cleaning maintenance was added to the calculations to provide an analysis on affect to anticipated payback schedules. The results showed cleaning costs only added 1 year to project paybacks and saved over 262,244 kWh over 20 years.

Effects of Natural Weathering on the Performance of High Solar Reflective Index Paint Surfaces Exposed in Harsh Climatic Conditions of United Arab Emirates

“…The Cool Roof Rating Council (CRRC), USA, determined that the SRI should be evaluated at the beginning and after 3 years of natural exposure to ascertain cool roof efficacy. This 3-year time period was recommended by most cool coatings manufacturers between the cleaning procedures and adapted by other major certification bodies, such as Energy Star and European Cool Roof Council (ECRC) [26]. However, this requirement of periodic maintenance varies based on location and depends on numerous factors, such as building characteristics, the specific type, and the properties of the coating.…”

Effects of Natural Weathering on the Performance of High Solar Reflective Index Paint Surfaces Exposed in Harsh Climatic Conditions of United Arab Emirates

“…The Cool Roof Rating Council (CRRC), USA determined that SRI should be evaluated at the beginning and after 3-years of natural exposure to ascertain cool roof efficacy. This 3-year time period was recommended by most cool coatings manufacturers between the cleaning procedures and adapted by other major certification bodies such as Energy Star and European Cool Roof Council (ECRC) [19]. However, this requirement of periodic maintenance varies based on location and depends on numerous factors such as building characteristics, the specific type, and the properties of the coating.…”

Archives of Thermodynamics

“…Analysis of these technologies is given by, among others, Santamouris [25,26]. One of options is application of cool roofs, that is, roofs with lowered surface temperatures of roofing covers [27][28][29]. Materials characterized with high reflectivity of solar irradiance and with high thermal emissivity [18,21,30,31] are applied to construct the cool roofs.…”