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We also carry Matrix, B.P., G.E., Sharp, Sanyo, Uni-Solar, Mitsubishi, Photon, Suntech, ALPS Solar Photovoltaic Panels

AIR COLLECTOR SYSTEM

Solar air collectors are similar in operation to liquid collectors with one major exception. Air is circulated through the collector and is the medium of heat transfer. Since air will not freeze under any normal circumstances on the planet, all of the techniques and equipment needed to protect liquid systems can be ignored. Air collectors are being used successfully today for such diverse applications as composting toilets, heating water and benzene removal from the earth. Their main functions are for solar space heating of homes and buildings.

When solar air systems were installed in the late 1970’s, most collectors were of questionable construction, with efficiencies of 40 to 50%. By 1985, efficiencies had risen to 60 to 70% and collectors were built with life spans up to fifty years. All high quality air collectors today have three things in common: an enclosure made of aluminum or steel, insulation on the back and sides and low iron, tempered glass glazing on the front. Collectors normally have a single glazing with a dead air space between the glass and the absorber plate.Absorber plates are made of aluminum, steel or copper. The plate is coated on the side facing the sun with black paint or a selective surface process. Selective surfaces (black chrome) increase efficiency by limiting reradiated energy back through the glazing. Air collector absorber plates should be dimpled or corrugated to create air turbulence that helps "wash" the heat from the plate.

When installed properly a 4 foot x 8 foot air collector can provide 25 to 50% of the energy needed to heat a 400 to 800 square foot space depending on climate and building construction. This makes air collector systems ideal for zone type heating systems. We normally use a separate blower, control and ducting system for every 32 to 64 square feet of collector area. The blower pulls air from the cold air inlet of the space through the collector and blows the heated air back to the hot air outlet. Optimum performance is achieved with a squirrel cage blower of approximately 200 to 400 cubic feet per minute of air flow. Smaller blowers can be used and performance is slightly effected, but they must be of a squirrel cage configuration. The system is controlled by a simple, reliable bi-metal switch in the collector which turns the blower on at 110° and off at 90°. This gives automatic operation with each sun cycle. An interior thermostat or manual switch wired in series with the bi-metal switch allows the occupant to "call for heat" or shut the system off when heat is not required. The system is completed with the addition of a backdraft damper in the duct system to prevent nighttime cooling from thermosyphoning.

Hot air rises and cold air falls. This concept of air movement, called natural convection, is important in any space heating project no matter what fuel is used. Wood stoves are superior to fireplaces in heating mainly because the stove causes a convection current of air throughout the room or building. Most fireplaces only radiate heat into the immediate area. Although this concept is ignored in designing many modern fossil fueled heating systems, it is an integral part of all successful solar heating installations. If a solar heating system works with natural convection, hot air rising and cold air falling, then the result in comfort level can exceed expectations.

Almost everyone today only lives in half their house - the bottom half. We need heat the most when the weather is cold and we are sedentary (sitting or lying down). In any building with little air movement the air tends to stagnate or stratify. Air temperature rises approximately 1°F. per foot. The ceiling of an A-frame house can be 20 to 25° hotter than the floor. Any good space heating system is designed around the fact that we live near the floor and the heat is at the ceiling. The cold air inlet to the heating system is the key to efficiency and comfort. To heat any given space, the cold air must be removed and circulated through the heater; therefore, the inlet must be ducted so it is on or near the floor. If the inlet is placed on the ceiling, the heater will tend to recirculate the hot air and leave the floor cold. The hot air supply may be placed at the ceiling or on the floor with little difference in performance. If placed on the floor, the hot air rises to the ceiling within a short distance. Since collectors are normally installed on the roof of the building being heated, it is best to place the hot air outlet in the ceiling to shorten the duct run. A system installed in this manner de-stratifies, or mixes, the air in a building like a ceiling fan, in addition to supplying solar heat.

The orientation of air collectors for heating in the winter. The collector should face within 30° of true south and

The main niche for air collectors in the solar industry is supplying 25 to 50% of required energy for space heating. Additional storage is not required in most cases. A normal, well insulated house has enough interior mass alone to store enough heat for three to four hours after sundown, if the temperature is raised 10°F. (i.e.,68° starting, 78° ending). More massive construction, such as adobe or brick, can store even more thermal energy. Due to their complexity, large rock and water storage systems are rarely cost-effective. They often require extraordinary maintenance.

The best features of air collector systems are simplicity and reliability. The collectors are relatively simple devices. A well-made blower can be expected to have a 10 to 20 year life span if properly maintained, and the controls are extremely reliable. Since air will not freeze, no heat exchanger is required. By using packaged insulated flex duct, the installation can be accomplished by anyone with a little mechanic ability. All this adds up to a quick payback.

ARTICLE BY: " OUR SOLAR MANUFACTURER OUT WEST "

PASSIVE SOLAR HEATING SYSTEM - SINGLE COLLECTOR - OHIO
 SCHWARK ELECTRICAL INC. SERVICED - 2001
CHANGED COLLECTOR PANEL & SERVICED SYSTEM
SET-IN SERVICE 1985

PASSIVE SOLAR HEATING SYSTEM - DOUBLE COLLECTORS - OHIO
SCHWARK ELECTRICAL INC. SERVICED - 2001
CHANGED COLLECTOR PANELS & SERVICED SYSTEM
SET-IN SERVICE 1980

SUN AIRE PASSIVE SOLAR HEATING SYSTEM - SINGLE COLLECTOR SYSTEM - NEW MEXICO
SOLD NOVEMBER 2007 - INSTALLATION SUB-CONTRACTED OUT
PURCHASED ON-LINE: SCHWARK ELECTRICAL INC.

AWAITING PICTURES - BEING INSTALLED
SHOULD BE POSTED IN 7 - 14 DAYS

COPYRIGHT 2001-2007 SCHWARK ELECTRICAL INC.

ALL RIGHTS RESERVED ERIC L. SCHWARK