How to Connect a Solar Panel to a Water Machine
Any household appliance can be powered by solar energy. A solar panel produces direct current (DC) electricity. This power must be converted to alternating current (AC) electricity in order for the solar panel to provide energy to appliances running on 115-volt AC power. A single solar panel will not provide enough power to run many appliances, but a 50-watt panel should be able to run an energy-efficient water cooler. A battery, a charge controller and a small inverter will also be required. Does this Spark an idea?
Instructions
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Unplug the water cooler. Look behind the unit for the label showing how much energy the cooler uses in kilowatt-hours (kWh) each day. Look also for the current in amps the cooler uses when running. Although a water cooler runs only part of the time, the solar energy system must be capable of providing enough current to run the small compressor in the cooler.
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Look at the back of the solar panel or consult the installation manual. Look for the rated power of the solar panel in watts. The energy produced by the solar panel is estimated by multiplying its power in watts by the average number of hours of sunshine each day in your location. As an example, if we take a location where there are five hours a day of sunshine on average over the year, a 50-watt solar panel will produce approximately 250 watt-hours of electricity each day. An efficient water cooler will use fewer than 200 watt-hours of electricity per day, so this solar panel would produce enough electricity to run the cooler.
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Determine the size of the charge controller and the power of the inverter. The charge controller must be sized to handle the maximum current produced by the solar panel. The inverter must be able to provide enough power to start up and run the compressor in the cooler. If the cooler takes 4 amps when the compressor is running, it is using 4 amps multiplied by 115 volts, which equals 460 watts of power. Compressors take more than their rated power to get started. So choose an inverter capable of providing this peak load.
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Calculate how many batteries you will need. A 12-volt battery will store about 1,200 watt-hours of electricity, so a single 12-volt battery should provide enough energy storage to run the water cooler for several days when fully charged.
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Decide where you want to place the battery. It should be inside the house in a cool, well-ventilated space. Measure the distance in feet from the solar panel to the battery, tracing the line the wires will take. The inverter should be installed not too far from the water cooler. Decide where the inverter will be placed and measure the distance in feet from the battery to the inverter. Add this distance to the first measurement and double it. You will need to buy this length of copper wire.
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Go to a store that supplies solar energy equipment--or go on the Internet--and buy the battery, the charge controller, the inverter and the copper wire. Check with the supplier what thickness of copper wire he recommends.
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Install the charge controller on a wall close to the battery and install the inverter close to the cooler. Follow the instructions in the installation manual for the charge controller and connect the solar panel to the controller. Then connect the controller to the battery. Finally, connect the charge controller to the inverter. Turn on the charge controller and let the battery charge for a day when there is plenty of sunshine. Then turn on the inverter and plug in the water cooler.
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Tips & Warnings
Some water coolers heat water as well as chill it. These appliances take more current and use more energy. If you only want cool water and not hot water, unplug the cooler and disconnect the heating element. Otherwise, you will probably need more than one solar panel, a second battery and a more powerful inverter. To find more detailed information on the average hours of sun in your location, consult the table given in the second reference.
References
- Photo Credit Solar hoch auf dem dach image by DevilGB from Fotolia.com
