Solar Collectors

Types• Back-pass solar collectors

– Used to heat air– Glazed surface– May be integrated with thermal mass

• Concentrating solar collectors– Best suited for clear skies– Steam production– Concentrates light at absorber which can increase efficiency at high temperature– Four forms: parabolic trough, parabolic dish, power tower, stationary solar collectors

• Trombe Wall– Thermal mass designed to radiate heat during the night– Glass to allow sunlight through– With added salt fillers stored energy changes from 200 cal/day to 80,000 cal/day

• Batch Solar Collectors– Water heating– Glazed water collectors

• Solar cookers• Liquid Solar Collectors

– Vacuum tubing

Manufacturers and ProductsSES Dish Stirling System Technology• Designers of large, industrial solar dish systems• Product made of huge concentrator (dish reflectors) and power

conversion unit (hydrogen heating that runs pistons)Industrial Solar Technology• Roof mount parabolic troughs• Specifications – IST Roof Mounted Trough (RMT) System• Reflective Module Size 120.75 in. x 45.2 in. (3067 mm x

1148 mm)• Gross Aperture Area 37.9 ft2 (3.52 m2) • Net Aperture Area 35 ft2 (3.25 m2)• Concentrator Weight 55 lb (25 kg)• Materials of Construction Aluminum• Reflective Surface Coated polished aluminum• With 1120 ft^2 area, produces 52 kWth

Manufacturers and Products

•Solarco Manufacturing Ltd.

•24 Tube Kit

•$2,100

•Works down to -40 Celcius

•93% light allowed in

•3.6 ft x 4.9 ft

Reflecting Surfaces

• Cool roofs– White surfaces preferred– Metal surfaces offer high albedos but low

thermal emittance– Reduce heating costs in hot environments

Reflecting Options

• Coatings ($.75 – $1.50 per square foot)– Elastomeric– Polyurethane– Acrylic

• Single-ply Membranes ($1.50 – $3.00)– Semi-flexible– EPDM, PVC, TPO

• Reflective tiles ($3.00)– Pigments allow for 70% reflection of sun’s energy

• Metal roofs ($2.00 and up)– With additional pigments will reflect infrared as well

Areas of further exploration

• Alternating cool roof/warming roof material?

• Designing our own trough system for heat

• Pigments for roofing

• Integration of a trough system

• Current research into reflecting light (moisture barriers)