stlbill
07-22-2015, 01:52 PM
Hello,
<Deep Breath>...
Thanks in part to this cooler Summer I have finally convinced my Wife we need a heater. I've read, "There is no such thing as too big of a heater." I think this might not be true. Someone please correct my newbie math:
Questions, first, explicit details follow:
1. Is my math even close to correct?
2. If we turn the heater on when the intake water is 82 degrees will the water returning to the pool be 98 and could that burn someone standing near a return?
3. Last question is about efficiency. I believe 1 gallon of propane is about 100,000 BTUs. Does this mean the heater will use 4 gallons per hour of operation?
Pool information:
Viking Gulf Shores model fiberglass outdoor IG pool built so that long sides are approximately North and South. House is less than 10 feet to East and timberline is up slight hill no more than 50 feet to the East. Climate is St. Louis, Missouri USA.
Officially the Gulf Shores is a 19,000 gallon pool, but we often fill it 1-2 inches above the ideal depth for skimmer effectiveness. Estimate 20,000 gallons.
For thermal efficiency guesses: Proposed heater is 400,000 BTU propane installed outside patio fence approximately 50 pipe feet from where water will enter the pool up to 4 underwater returns. All pipes will be underground between heater to pool.
Pump is Hayward 1.5 HP IG Superpump with 1.5 inch plumbing. Filter is 72 ft^2 Hayward DE. Pressure is usually 11-20 PSI depending on return and intake routing, if pressure gauge is accurate. I do not have a flow meter installed currently, but expect to have one added as part of this upgrade. The pump is rated at up to 70 GPM, but I expect I am circulating about 50 GPM.
The pool will be covered with a 12 mil solar "blue top/black bottom" cover except when in-use.
Now for the math and assumptions:
1. A heater advertised as 400,000 BTU introduces at most 400,000 BTUs of heat per hour not including thermal losses.
2. If 50 gallons flows through the heat exchanger per minute that is 3,000 gallons per hour.
3. 400,000 BTUs per hour into 3,000 gallons (25,000 pounds) of water is about a 16 degree rise at the returns which will mix with the other 17,000 gallons of water.
Hope I give you enough information to answer my questions.
Thank you in advance!
-Bill
<Deep Breath>...
Thanks in part to this cooler Summer I have finally convinced my Wife we need a heater. I've read, "There is no such thing as too big of a heater." I think this might not be true. Someone please correct my newbie math:
Questions, first, explicit details follow:
1. Is my math even close to correct?
2. If we turn the heater on when the intake water is 82 degrees will the water returning to the pool be 98 and could that burn someone standing near a return?
3. Last question is about efficiency. I believe 1 gallon of propane is about 100,000 BTUs. Does this mean the heater will use 4 gallons per hour of operation?
Pool information:
Viking Gulf Shores model fiberglass outdoor IG pool built so that long sides are approximately North and South. House is less than 10 feet to East and timberline is up slight hill no more than 50 feet to the East. Climate is St. Louis, Missouri USA.
Officially the Gulf Shores is a 19,000 gallon pool, but we often fill it 1-2 inches above the ideal depth for skimmer effectiveness. Estimate 20,000 gallons.
For thermal efficiency guesses: Proposed heater is 400,000 BTU propane installed outside patio fence approximately 50 pipe feet from where water will enter the pool up to 4 underwater returns. All pipes will be underground between heater to pool.
Pump is Hayward 1.5 HP IG Superpump with 1.5 inch plumbing. Filter is 72 ft^2 Hayward DE. Pressure is usually 11-20 PSI depending on return and intake routing, if pressure gauge is accurate. I do not have a flow meter installed currently, but expect to have one added as part of this upgrade. The pump is rated at up to 70 GPM, but I expect I am circulating about 50 GPM.
The pool will be covered with a 12 mil solar "blue top/black bottom" cover except when in-use.
Now for the math and assumptions:
1. A heater advertised as 400,000 BTU introduces at most 400,000 BTUs of heat per hour not including thermal losses.
2. If 50 gallons flows through the heat exchanger per minute that is 3,000 gallons per hour.
3. 400,000 BTUs per hour into 3,000 gallons (25,000 pounds) of water is about a 16 degree rise at the returns which will mix with the other 17,000 gallons of water.
Hope I give you enough information to answer my questions.
Thank you in advance!
-Bill