Hot tub heated with solar.

bob eck

Take a look at using triangle tube pool and spa heat exchangers.

Big Will

We installed Solar storage

for domestic and heating in slab. The Primary storage tank is a Buderus with two coils. The customer wants to heat his hot tub with the solar when possible. My first thought is a brazed plate heat exchanger with cupero nickle plates. I am worried about the chemicals eating the heat exchanger.

hot_rod

what about their skin?

if the chemicals are strong enough to eat away copper, yikes!

Copper boilers have been used for a long time on pools and spas.

There are a number of stainless and Ti stainless heat exchangers available for pool and spa use.

How much of a spa and how much of a load? Is it mainly to dump excess solar? Or are you trying to heat all or a portion of the spa?

Use the output specs from the SRCC website to see how much energy you could expect to have available, after the DHW load is handled.

Consider a dual coil tank that has a stainless steel coil. Heat Flo is one brand that comes to mind. Perhaps the spa water could flow right into the coil?

Regardless keeping the spa chemistry is the key to a long lasting HX whatever the material.

hr

Derheatmeister

Maxiflo from TT

I am interfacing a 9 panel system to a Hottub next week! we will use the "Maxiflo" from Triangle like we have done before!
works great! Good luck.Richard.

Edit: just make sure that you use the SS nipple kit with the sensing port before you adapt to the PVC!

tim smith

Hot tub would be a great solar dump location?? would it not

Kevin Koenig_4

Plate HX's

You will have signigigantly better heat transfer abilitys using braised plate heat exchangers in this application. The shell and tube are reliable but the performance of a plate with relatevely low differential temperatures blows the shell and tube away. Be sure to plce it at the discharge of the filter and use flanged connections when going fron metal to plastic pipe. A MRHL is also important here. If the spa flow gets too low the outlet side of the HX may melt the pvc piping. See attached link. B&G manufactures these in Buffalo N.Y. Kevin http://www.bellgossett.com/literature/files/6826.pdf

Kevin Koenig_4

Plate Heat Exchangers

Plate heat exchangers will give you considerably better performance in this application. Be sure to locate it at the outlet of the filter and before any chlorine is injected. Shell and tube type is reliable but can't come even close to the performance of a plate. You may need a MRHL at the outlet of the pool side in the event the flow drops too low. This can damage plastic piping. B&G manufactures there own plate heat exchangers in Buffalo N.Y. http://www.bellgossett.com/literature/files/6826.pdf