The concept of collecting solar radiation for heat is familiar to us all. Each of us has enjoyed the rewards of passive radiant heat collection while sitting in the sun at a window or in our car on a cold sunny day. The glass allows the short wavelengths of the sun’s radiation to enter and in striking the interior surfaces become long-wave radiation and radiant heat. Yet, we generally live and work in structures that use very limited quantities of this solar radiant heat source, choosing to use conventional heat sources and fuels (gas, oil, electricity) that are easily converted to radiant heat and controlled throughout the day and night, regardless of the weather.
Across much of North America, there is enough radiant solar energy hitting the roof of an insulated house on a winter day to totally replace the heat loss over 24 hours. The same structures that we heat by conventional means receive an enormous amount of radiant heat energy from the sun. On a typical January day in Indianapolis at ~40° north latitude, the available radiant energy from the sun averages 994 Btu/day for each square foot of vertical wall surface open to the sun and 1034 Btu/ sqft/day on a surface with a 45° pitch (Purdue University Cooperative Extension Service Bulletin AE-108 (http://www.ces.purdue.edu/extmedia/AE/AE-108.html). A 20x40 ft single story house, with the longest wall facing south and 8x40 ft= 320 sqft exposed to the sun, would have a total solar radiant exposure of 318,000 Btu/day. The south facing roof with a 45° pitch (14x40 ft= 560 sqft) would have a solar exposure of 579,000 Btu/day.
In the 1970s, architects and early pioneer “green builders” began to design methods of capturing this unused solar radiant energy with solar walls, attached sunspaces, and more advanced radiant collection systems, e.g. solar envelop homes. In the past four decades, solar walls have advanced from passive spaces for collecting and retaining solar radiant heat to active systems using fans and/or heat exchangers to transfer the radiant heat to living spaces. The evolution of these systems was stimulated by individual home and business owners seeking to diminish their conventional heat requirements with a vast array of collection methods and materials. Their innovations have been followed by more advanced manufactured solar hot air devices and systems.
Today, there are several marketed solar hot air systems that actively and efficiently draw hot air from a solar collector mounted on the wall or roof to directly warm interior spaces. These simple forced solar air heat designs are widely recognized as some of the most cost effective and efficient renewable energy systems in use. The marketed systems typically pay for themselves in reduced heat costs in just 3-5 years.
For all the advancement in our solar air heater design, most of the collectors have one thing in common; they look like solar collection systems. In many communities, the black panels on the walls or roof are both common and accepted. However, in many other communities, and for many homeowners, the changes to the home’s appearance required to incorporate a solar air heater on the home’s south facing exposures is prohibitive. Thus, this efficient and cost effective renewable heating technology is dramatically underutilized across North America.
eVANTICO, Inc. (evantico.com) has designed the SOLYTE product line to overcome these barriers and expand the use of this highly efficient and cost effective technology for supplemental home heating. The durable device is designed for roof installation and will provide years of efficient renewable solar heating for the home. Two sizes are offered.
Solar radiation passes through tempered solar glass and is absorbed by the specifically designed corrugated/perforated coated aluminum absorber plate with >80% efficiency in collecting the sun’s radiant energy. Air is drawn from the living space, through the back of the solar heat device on the roof where the air temperature is >110°F during operation; heated air is returned to the room. A digital room thermostat controls the circulation fan. A separate thermostat in the solar collector ensures only hot air is circulated.
The SOLYTE product line is engineered to provide homeowners, architects and builders with the performance of a highly efficient solar heat collector without looking like one. The double-frame construction gives the SOLYTE durability with the appearance of a conventional skylight. This unique design has the performance and appearance to please the most discriminating homeowner and allows the SOLYTE to be installed in many locations where other solar collectors would not be desired.