Solar Hot Water

Gary FlomenhoftBSME, MAPP, CEEResearch AssociateGund Institute, SNR

Developing world renewable energy workshops

SOLAR HOT WATER SYSTEMS

Collectors-POOL

Collectors-POOL

Collectors-Flat Plate

Collectors-Flat Plate

Collectors-Evacuated tube

Collectors-Evacuated tube

Passive Batch Heater

Passive Thermosyphon

Freeze Protection-Draindown

Solar Collector 6. Collector Return Breaker 11. Tank Drain 2. Vent/Vacuum 7. Collector Supply 12. Tank Drain Fitting

3. Hot Water to Taps 8. Drain Down Valve 13. DHW Electric Tank 4. Cold Feed 9. Circulating Pump 14. Immersion

Heater 5. Tempering Valve 10. Drain

Freeze Protection-Draindown

The Sunspool draindown valve was popularly installed in the 1980's, but is no longer manufactured.

Draindown systems have proven to be the most problematic of all freeze protection systems. They are vulnerable to frozen vacuum breakers and air vents, damaged sensors or wiring, lack of proper pipe drainage, and malfunctions with the draindown valve. This type of system is rarely installed new any more, and is not recommended.

Freeze Protection-Drainback

Drainback

Drainback

Drainback system

Freeze Protection-Closed Loop

External heat exchanger

W/solar tank

External heat exchanger and expansion tank

External heat exchanger

External heat exchanger

Heat and Hot Water

Wood backup

Installation

Installation

Sizing Solar Hot Water

Conservation:Turn down Thermostat to 120-125degWrap the water heater with insulating blanketFix drips in faucetsEfficient showerhead and faucet aeratorsInsulate hot water pipes in unheated space

Sizing Solar Hot Water

US Usage:

15-30 gallons per day/person

Family of 4 = 80 gallons

One square foot/.75 gallon of collector in NE= 107 sq ft

100% in summer, and 40% in winter

Instantaneous backup