Your Questions About Solar Panels For Home Use In The Philippines

Henry Dover answers:

Try 3,500 Watt for a central home air conditioner and 150 watts for a fridge, however a fridge works in bursts and there’s a high demand when the compressor starts so it’s really takes about 1,000 watts. If you’re grid tied, the peaks aren’t a problem, you just draw from the grid and feed it back slowly. If you run off batteries, they are 50% efficient at charging. The inverters to produce AC power are about 65% efficient. If you are grid tied, you can design for your average use. If you are running grid free then you have to design for peak loads. Batteries help with the peak loads but at the 50% charging rate, the need for a battery room, they’re expensive and they can explode. You will want a backup such as a generator or grid tied incase the Sun doesn’t come back in one day.

If we just use your numbers, 500 watts for AC for 12 hours, 40 W for fridge, 100 W for TV but say for 4 hours each night then you have 500 * 12 + 40 * 24 + 100 * 4 = 7,360 Watt Hours per day. Take into account the 50% efficiency of batteries and the 65% efficiency of the inverter and you have 7,360 / ( 0.5 * 0.65 ) = 22,646 Watt hours. Assume 8 hours of usable sunshine and 9 days out of 10 of usable sun and you’ll need 22,646 / 8 * 10 / 9 = 3,145 watts. To last two nights and one day to survive one day of no sun, you would need to store 1.5 * 22,646 Watt Hours = 33,969 watt hours which would be 33,969 / 12 = 2,831 Amp Hours.

So you would want about 32 100 Watt solar panels which would cover about 256 square feet, you would need 48 lead acid batteries of 60 Amp Hours each. A charge controller and an inverter.

These are just rough guesses but it sounds like you would need $16,000 of panels, $5,000 in controllers and inverter, and $4,800 in batteries for a total of $25,800. If your power from the grid is 10 cents per kwh, this investment would represent a 1.8% per year loss. Since the 10 year US Treasury bonds pays 2.24% per year, this would not be a rational decision. You’ll have to hope for government incentives to make this project viable.

Note, lighting isn’t part of the calculations but you can just trim down your TV viewing time.

Henry Dover answers:

Http://www.sophilcor.com/ is a Philippine source for solar products
Sulit has several dealers listed too in classified
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http://www.sulit.com.ph/index.php/classifieds+directory/q/solar+panels

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Here is a solar water heater here http://philippinestuff.wordpress.com/2009/09/15/solar-water-heater/
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A friend from Greenpeace gave me the contact number of their Climate and Energy Campaigner who can give you the details on where to get a solar panel. Please call Abby Jabines at 0917-8864767.
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Their office has a basic solar panel set-up that can power everything except A/Cs and refrigerators, I think. Since I cannot afford it, I’m doing the Greenpeace “Take action” campaign (http://www.greenpeace.org/international/campaigns/climate-change/take_action) na lang