Listeroid to heat and run a hot tub?

[Tom]

A long time buddy of mine was over today and was oggling the 'roid. So any way he wants one bad and is trying to figure out what to do with it and we came up with the idea to heat and run a hot tub. Use the generator to run the jets and pump and heat the water in the water jacket of the engine. Add a little scented biodiesel and who knows, it could be the start of a new fad.

[LowGear]

And hook the engine platform up to the hot tub and have massage vibrator seating.  I think we're going somewhere with this innovation.

Casey

[ronmar]

Well lets do some numbers...  A 4-6 person hot tub will have 400-500 gallons of water in it?  That is 3200-4000 pounds of water.  To heat that much water from say 50F to 80F will take between 96KBTU and 120KBTU.  A 6/1 puts out about 17KBTU/HR from the cooling system at full load.  The heat alone from the engine would take between 5.6 and 7.1 hours to heat that much water 30F.  The jet pumps wouldn't be needed during warmup, so the 3KW of electric power could be used for electric heating elements.  Each KW sent to an electric water heating element is good for about 3413 BTU, so that is about another 10.2KBTU per hour at a 3KW electrical load..  The combined rates make for 27.2KBTU/HR and at that rate would heat the tub 30F in between 3.5 and 4.4 hours?  80F is not a real hot tub, so for 90F, those times would be 33% longer.  For 100F would take around 66% longer.  These times will also be longer due to evaporative cooling if the tub is not covered...  

Now what might be cool is a small wood fired boiler thermosiphoning to the tub to warm the water, and a lister driving the pumps for circulation and to maintain the heat when you are actually using the tub:)

[Roark]

An idea for anyone looking for heat-storage:  Take a peek at a hot-tub design made by "Sof-Tub".  These are made entirely from very thick structural foam.  They're known for their insulating capabilities.  (They use the heat from the pump motor to heat the tub.  It takes a couple of days to reach a comfy temp, but once it's there, it stays very warm). The sides and bottom are heavy-duty semi-flexible foam 4 to 6 inches thick. The top of the tub is sealed with a removable foam cover about 6 inches thick.  A very well insulated system indeed.  They hold about 400 gallons.

You can often find these things, discarded by owners who don't know how to take care of them, for next to nothing.    Rarely is the foam damaged.  Usually it's the liner that's shot, and it's often repairable with very little effort. (They come with a repair kit).   If the entire liner is missing, consider taking the whole schmutz down to your local spray-in bed-liner guy and have him shoot the inside with polyurea.  

These tubs might made an ideal thermal storage system for someone.

Roark

[LowGear]

Our tub has got to be at least a 4 person unit.  We can run it at 102 degrees on a 120 volt * 15 amp circuit which means 1800 watts (1.8 KW) or less.  Always remember what Barbie said.  "Math is hard!"

I think the Soft-Tub things are neat too but getting one to work as a massage chair would be tricky.

LowGear

[xyzer]

Now what might be cool is a small wood fired boiler thermosiphoning to the tub to warm the water, and a lister driving the pumps for circulation and to maintain the heat when you are actually using the tub:)

I've done that...First we were in the middle of nowhere and thought lets build a hot tub...Our first venture we had a 6' dia galvanized water trough and laid an aluminum siphon in upside down (its hanging low in the water) with a weed burner blowing through the siphon tube...took awhile but it worked....don't touch the tube!!!!. Our next outing I had a hemispherical steel forging from work welded a plate to the bottom of it and had a hose in and a hose out run to the hot tub....built a fire and kept it going worked well...it could have used larger hose ....it would build pressure and the steam would blow the water out of the heater then fill back up and repeat the process...awww the good old days! Now I guess a lister waiting for a power failure could be kept busy!
Dave   

[Tom]

This could raise the Lister CD up a few notches on the chick magnet scale. 

[xyzer]

This could raise the Lister CD up a few notches on the chick magnet scale. 

Hmmm..........let me think ...... yea it was a good chick magnet! We had great time in the hot tub.....wait now I remember! My buddy and I married em....hmmm they don't like our way of hot tubing anymore?!!! What went wrong?!.....it must have been the wedding cake

[Tom]

That'll do it.

[Roark]

Here ya go.    $400, complete and ready-to-run, and it seats six.   Has an R-factor of something like 40+, too.

http://cgi.ebay.com/SOFT-HOT-TUB-JUCCUZZI_W0QQitemZ130284256156QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item130284256156&_trksid=p3286.c0.m14&_trkparms=66%3A2%7C65%3A15%7C39%3A1%7C240%3A1318

Disclaimer: I have no financial or proprietary interest in this.  Don't know the guy. Don't know the item personally.  Just did an eBay search and it popped-up.

Roark

[AdeV73]

Here ya go.    $400, complete and ready-to-run, and it seats six.   Has an R-factor of something like 40+, too.

http://cgi.ebay.com/SOFT-HOT-TUB-JUCCUZZI_W0QQitemZ130284256156QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item130284256156&_trksid=p3286.c0.m14&_trkparms=66%3A2%7C65%3A15%7C39%3A1%7C240%3A1318

Disclaimer: I have no financial or proprietary interest in this.  Don't know the guy. Don't know the item personally.  Just did an eBay search and it popped-up.

The seller pulled it already. He must have seen this thread.... 

PS: Is the R-factor the same thing as WAF ?

[Doug]

Why not justa 4 stroke outboard.....

The unwanted guests have to sit near the prop

[ronmar]

You know, You could also direct the listeroid exhaust into the water system for bubbles in the tub and reduced exhaust noise:)

[mobile_bob]

ya and burn baby oil and you would come out of the hot tub
nice and baby butt soft



bob g

[Tom]

What an amazingly creative bunch of  people.