Overview
System type: Custom-designed drainback solar hot water/radiant heat
Production: 5.92 million Btu per month average
Climate: High desert (7,000 ft. elevation; -2°F design temperature)
Domestic hot water produced annually: 95% of DHW; 75% of total heating & DHW load
Solar Equipment
Collectors: Six Apricus AP-30
Collector installation: Roof-mounted, south-facing, parallel to the roof (approx. 45° tilt)
Heat transfer fluid: Distilled water
Circulation pump: Grundfos 26-99SF
Pump controller: Resol DeltaSol Pro
Storage
Tanks: Two 250-gal. insulated polypropylene tanks, 200 gal. water level
Heat exchanger: Custom site-built, 180 ft., 3/4-in. coiled copper
Backup DHW: Two 40-gal., electric water heaters
System Performance Metering
Thermometer: Digital, built into solar controller
Flow meter: Pentair LDF239B flow meter
Radiant Floor System
Tubing: Rehau cross-linked PEX
Amount of tubing: 2,900 ft.
Number of zones: 6
Circulation pump: Grundfos 26-64SF
Pump Controller: Wirsbo
Tempering valve: Honeywell AM101R-UT, set to 110°F
Backup Radiant Heat: Two 30-gal. electric water heaters
