Heating, water/SWG circulation for a new in-ground spa

[eco-help]

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Forgot to add:
Spa will spillover to pool &
I did see in the Hayward SWG Wiki about temperature >92 causing overamp = use less salt..
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We are looking into a new spa (8' round) as an addition / renovation of existing pool.

Pool company is saying they will use the existing pump to heat the spa / pool with a valve to switch water flow from one to the other. They will run a new line to the spa to accomplish this.

How many degrees of temperature per hour could I expect from the heater (to heat the spa)?

How will this impact pool / spa water / chlorine circulation / generation?

Anything I or the pool company haven't considered?

Thank you!

 

[mknauss]

Will you be using your Heat Pump to heat the spa? It will be quite slow. Spa heat normally needs a gas heater unless you are willing to wait several hours to heat the spa.

When you heat the spa, you isolate from the pool system. When you are done with the spa, the system intermingles. Each time you wish to use the spa, you re-heat the water for the spa.

 

[eco-help]

Will you be using your Heat Pump to heat the spa? It will be quite slow. Spa heat normally needs a gas heater unless you are willing to wait several hours to heat the spa.

Yes exactly I will be using the HP for the spa and want to know for every hour how many degrees can I expect it to heat?

When you heat the spa, you isolate from the pool system. When you are done with the spa, the system intermingles. Each time you wish to use the spa, you re-heat the water for the spa.

Got it thank you.

 

[flynwill]

Yes exactly I will be using the HP for the spa and want to know for every hour how many degrees can I expect it to heat?

That is a fairly straightforward calculation, but you need the know the volume of your proposed SPA. Rough guess based on an average of 3' deep for 8' round is 150 cubic-feet = 1122 GAL = 9363 lbs. A BTU is the amount of heat needed to heat one lb of water on degree F. I couldn't find your HP specs but guessing that it's output probably about 75,000 BTU/hr when trying to reach SPA temperatures, works out to about 18 degrees F per hour.

 

[eco-help]

That is a fairly straightforward calculation, but you need the know the volume of your proposed SPA. Rough guess based on an average of 3' deep for 8' round is 150 cubic-feet = 1122 GAL = 9363 lbs. A BTU is the amount of heat needed to heat one lb of water on degree F. I couldn't find your HP specs but guessing that it's output probably about 75,000 BTU/hr when trying to reach SPA temperatures, works out to about 18 degrees F per hour.

Thank you!
I don't know depth just that it is 8' round.. I will find out..

I did a search and one site shows 135,000 BTU... factoring the age of unit (>10yrs and assuming HP's become less efficient over time) 75K would seem to be a decent compromise.
So just about 3hrs to heat from 50degrees to 104.. (assuming I did that right) doesn't seem too bad at all!

 

[flynwill]

The available heat output is related to the difference in temperature between the water. The rating numbers you find are for 80 degree water with 80 degree air. (Zero difference). But if you look closer at the specifications there will usually be rating for 80 degree water and 50 degree air (30 degree difference). Heating 100 degree water from 70 degree air is probably compable (but likely slightly worse). And yes age is a factor, but mostly because the evaporator coils get dirty and/or corroded. Keeping the coils clean by hosing them out once or twice a year will help the efficiency.

 

[eco-help]

The available heat output is related to the difference in temperature between the water. The rating numbers you find are for 80 degree water with 80 degree air. (Zero difference). But if you look closer at the specifications there will usually be rating for 80 degree water and 50 degree air (30 degree difference). Heating 100 degree water from 70 degree air is probably compable (but likely slightly worse). And yes age is a factor, but mostly because the evaporator coils get dirty and/or corroded. Keeping the coils clean by hosing them out once or twice a year will help the efficiency.

Thank you. Seems that as long as we plan ahead in the morning we should be ok.

 

[eco-help]

Link to Aqua Cal SQ155 documents (owners manual, brochure, etc)

AquaCal HeatWave SuperQuiet Heat Pump 135,000 BTU's - SQ155 - INYOPools.com

SQ155 - AquaCal HeatWave SuperQuiet Heat Pump 135,000 BTU's

www.inyopools.com

If this violates a forum rule please delete this.

Thanks again

 

[eco-help]

Update: We decided no to in-ground spa, now looking into hot tubs... thanks everyone for helping with this.

 

[CedarChuck]

Update: We decided no to in-ground spa, now looking into hot tubs... thanks everyone for helping with this.

The in ground spas are ethnically pleasing but with today's/tomorrow's energy prices they really don't make sense any more. My Sundance Optima is 18 and still running strong. Highly recommend that brand.