Year-Round Energy Balances with Fiberglass Solar Screening

T HAS BECOME increasingly apparent that energy saving products with I short term payback qualities, increased longevity, low initial installation cost, and aesthetically pleasing appearance, are overdue in the world marke tplace. It is f e l t that one such product is Phiferglass Sunscreen@. Although this product has in i t s four year history undergone numerous tests to determine shading coefficients, strength, fire retarding capabilities, and is manufactured meeting criteria established by the Screen Manufacturers Association, a need was fe l t to determine results of the product under stringent laboratory conditions. The author's company's has had an ever increasing amount of inquiries from technicians in the commercial building field as to effects of our product when left in place year-round. Th,ese inquiries have prompted our authorizing the National Certified Testing Lab of Alexandria, Virginia, to institute stringent laboratory analysis of the capabilities of fiberglass solar screening. Some interesting possibilities had been implied in studies addressing the thermal performance of wind reducing porous screening and its effect on the annual energy balance. The question we sought an answer to was "Could the effect of lower thermal conductivity on heat lo& or gain come close to equalizing the potentially beneficial winter solar heat gain if the solar screens were left in place the year around?" Earlier studies by leading authorities in the fenestration field had established a heat transfer coefficient tha t they hypothesized would be attained by reducing 15 mph violent wind to 2 mph with the use of exterior mounted wind reducing porous screening. This hypothesis indicated that a reduction in wind velocity would