Is Solar still cost efficient in Ontario?

I have three solar panels that need to run most of the day in order to keep my pool at a comfortable temperature
http://www.wsetech.com/Solar%20Heater%20Yukon.jpg

the problem is that recently the Ontario government changed their electricity rates to this
http://www.hydroone.com/TOU/Publishi...ummer_2011.jpg
off-peak (shown in green below) 5.1¢/kWh
mid-peak (shown in yellow below) 8.1¢/kWh
on-peak (shown in red below) 10.0¢/kWh

Considering that I need to run my 3/4HP motor during peak time at 10.0c/kWh hour, I am wondering if it is still cost efficient to have my solar panels, or if I should just filter my water at night and use my gas heater when ever I need heat.

How would I calculate the electricity usage of my electrical motor?

How would I calculate how much it would cost to heat my pool with gas assuming 20¢/m³ of gas?

Does this add up?

.75 Hp = .56kWh
@.80% efficiency = .45kWh
to run the pump for 8 hours at peak time is 0.45kWh * 10c * 8h = 36 cents?:confused:

Gas
79 to 86 =7F
1 BTU is required to raise 1 pound of water by 1F
lets assume 1 gallon weighs 8 pounds
To raise the temperature of 10,000 gallons of water by 7F requires
10,000 * 8 * 7 = 560 000 BTU

1 cubic meter of gas contains 36267 BTU and costs 20 cents.
assuming 80% efficiency, therefore 29000 BTU at 20 cents.
560,000/29,000=19.31 19.31*.2=$3.86

So to heat with gas will cost approx. $4 dollar, what my solar panels can do in 8 hours for 36 cents, does this add up?:confused:

Splash,
Think you went the wrong way with the efficiency. 80% eff would put you at 0.71 KW.
I don't know how accurate those numbers are but the most accurate way would be to measure the real current draw under actual load and calculate from there.
Theoretically it's 756 watts per HP but the motor efficiencies vary widely.
Al

Is that snow in the picture?

Carl

I'm also in Ontario and subjected to Time Of Use Rates. I have a 1hp motor which as stated is about 746 watts or .75 kwh. Because they never run at 100% efficiency let just say that your 3/4 hp draws the same as a 1 hp is rated at while I calculate my 1hp at 1kwh or 75% efficient. At peak rates your paying $1.80 a day. Less than you spend at Timmy's for coffee. As far as the gas usage I turned my Rapak 255 gas heater on and went to the gas meter and timed the amount of flow per minute. I came up with about 2.00 /hr to run the heater. I get approximately 1 degrees rise per hour in my pool. I've looked at a few solar heaters and based on the initial investment it has never been worthwhile to purchase or even build one. I can run my heater for hundreds of hours for the same money which I never do. I use the heater to get the temp up at the beginning of the season ..let the solar blanket maintain it through the week and then a bit on the weekend depending on weather and/or occasion eg. pool party, spouse whining etc ;) The fact that you have a solar system already would make me believe that you're way ahead in just running your pump 24 hrs a day.

Yes that is snow in the picture but that is not my installation but a picture from the manufacturer.
These particular panels are capable of heating water even in winter.
Here is a picture of my panels.
http://i1194.photobucket.com/albums/...solarpanel.jpg

I measured the current draw with an Amprobe and got 9.1 Amps
9.1Amps * 120Volts = 1092W or 1.1KW
So this means that it will cost 11 ¢ per hour to run my pump.
It takes my solar heaters eight hours to raise the pool temp from
26C to 30C, so that will only cost me less than a dollar.

I am now satisfied that my solar panels, in terms of dollar value compared
to gas are unbeatable.

Thanks for your help everyone!
Glenn you are absolutely right, the upfront fee for the panels may not be worth it for everyone.
My cost was under $500 each, I did the installation myself so saved my self some money there.