Home’s Water Can Be Heated With Solar Panels
QUESTION: I live in a warm climate. I would like to install two water-heating solar panels on my roof and connect them to my electric hot water tank so that hot water from the roof enters the tank through the cold water inlet. Will you please discuss this in your column?
ANSWER: Over the years, a number of designs have evolved for heating water with solar panels. One common system uses an antifreeze solution circulating through the solar panel. The system also uses a storage tank that functions as a heat exchanger. It transfers heat from the antifreeze solution to the domestic water. By using two sets of coils, the system prevents the potable water supply from being contaminated if antifreeze should leak.
In areas where the temperature never drops below freezing, you can run potable water from the collector directly into the water heater.
Also, some designs do away with a water heater. The collector’s capacity is large enough so that it serves directly as the water heater.
Collectors are usually installed facing south and tilted on an angle. Since the angle of the sun changes with the seasons, the collector’s angle becomes a compromise. A rule of thumb is that the collector panels have a tilt equal to latitude plus 5 degrees measured from horizontal.
If the collector panels are mounted on the roof, make sure to mount them on brackets that provide adequate strength. Solar panels are subject to uplifting force by wind striking the undersides, and they should be built to withstand gusts of 100 mph.
For more information, contact the Real Goods Trading Corp., 966 Mazzoni St., Ukiah, CA 95482; (800) 762-7325. The company sells solar heating products and provides design and installation information.
Pump Can Help Water Move Up to House
Q: Our home is higher than the houses in the surrounding area. The municipal water system that we are connected to does not seem to deliver adequate pressure for our elevation. Is there a device that can boost our water pressure?
A: You need a booster pump, a pressure tank and a pressure switch. There are various size pumps, but because water pressure for residences is usually between 30 and 50 psi (pounds per square inch) you can get a pump that boosts the pressure 25 psi above street pressure.
The pump should be connected to the inlet water pipe and discharge into the pressure tank. The tank’s outlet should be connected to the house water distribution pipe. The pressure tank can be quite small and will function only to maintain the pressure. The pump is activated whenever water is drawn.
Depending on your requirements, you could get a larger tank with more storage capacity. The water will be stored under pressure until it is needed. As water is drawn from the system, the pressure in the tank will decrease. Upon reaching a preset minimum pressure, the switch will activate the pump.
ITT Bell & Gossett manufactures the type of centrifugal pump that you need. Write the company at 8200 N. Austin Ave., Morton Grove, IL 60053; or call (800) 542-6655. Ask for a distributor in your area. The distributor should be able to provide you with the name of a plumbing supply house in your area that can sell you the parts.
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To submit questions, write to Popular Mechanics, Reader Service Bureau, 224 W. 57th St., New York, NY 10019. The most interesting questions will be answered in future columns.
