Small Off-Grid Solar Hot Water Collectors

1. Off-Grid Solar Hot Water Collector:

This video illustrate how a Sunmaxx hot water collector works

http://www.youtube.com/watch?v=SPt93nX8iwI

It is a Sunmaxx - 55 gallons tank + 20 evacuated tube system, for $1,300

China made smaller system for 20 gallon tank + 10 evacuated tube, price is $750

2. China made 20 gallon Bare bone Solar Collector: $199.99 plus $30 shipping

1) Size:40" x 40" x 1".

2) Absorber area: 10 square feet. 

3) Weight: 10 lb.

4) Capacity: Minimum 20 gallons of hot water

5) Made of 8 copper tubes and aluminum fins with highly efficient absorber coating (all

metal, no plastic). Ultrasonic welding. Made in China.

6) Heating Fluids:

Water 

Water is nontoxic and inexpensive. With a high specific heat, and a very low viscosity, it's easy to pump. Unfortunately, water has a relatively low boiling point and a high freezing point. It can also be corrosive if the pH (acidity/alkalinity level) is not maintained at a neutral level. Water with a high mineral content (i.e., "hard" water) can cause mineral deposits to form in collector tubing and system plumbing.  Distilled water is a good choice!

Glycol/water mixtures 

You may consider using Propylene Glycol (non-toxic antifreeze liquid) in the collector-radiator loop, mixed with water in concentrations that will prevent damage from freezing to the lowest anticipated temperatures in your region.

Glycol/water mixtures have a 50/50 or 60/40 glycol-to-water ratio. Ethylene and propylene glycol are "antifreezes." Ethylene glycol is extremely toxic and should only be used in a double-walled, closed-loop system. You can use food-grade propylene glycol/water mixtures in a single-walled heat exchanger, as long as the mixture has been certified as nontoxic. Make sure that no toxic dyes or inhibitors have been added to it. Most glycols deteriorate at very high temperatures. You must check the pH value, freezing point, and concentration of inhibitors annually to determine whether the mixture needs any adjustments or replacements to maintain its stability and effectiveness. 

3. 12V Water heat Fork -$59.99 plus shipping, drawing power from 12V battery pack!

    Unlike the instant Electrical Water Heat, need 3~5KW for instant hot water!

    This consumes only 200 watts power from the Solar, Wind generator or 12V battery!

    Good back up heater for solar hot water when the heat sensor detects temp in water tank 

    lower than 120F!

    110VAC - heating element is only $7.99/pc

4. Solar 5 Gallon hot water bag or bigger Plastic Water tanks

You can even use a black PVC bag or a large plastic PVC containers to make hot water.

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