Spa temp and energy usage

[Nhbeacon]

So Sales beat me to the addition of warm bodies to the circulating water, now what happens when the icy mug of beer makes contact with the water? Or when the condensation freezes on the cover while you are in the tub, what does that do to the rate of heat loss? Then when the foam forms on the tub, does that act as an insulator?

I get enough of math word problems with my High school students in my Resource room, funny how the thread went the way of my week. But I think I did learn something.
Jan

[stuart]

Well, I check at home in the morning as I am checking my regular mail ( and trying to decide whether or not to order viagra or some "extensions" ) then I check at night when I get home ( assuming I can get computer time from my 14 y/o son.  

I agree with rocket, your a great addition. Although with a name like "rocket" he's probably been on the same viagra website you have!  

Here's a thought for you, try the viagra on your hair and you won't need the extensions!

be carefull with that stuff around a 14 year old boy though, by the time you get it away from him he could wind up with 3rd degree burns on both hands!!

[rocket]

Not only is this a fun and enjoyable forum but I actually am learning a few things too.  I hope that the otential spa customers enjoy this as much as we do.  

[Vinny]

Here's the answer to the bodies in the water.

Yes, if the water is at 95 and you have 6 bodies at 98.6 then the bodies will try to warm the water. Now with this said - I'm talking about just sitting there, it's NOT doing anything fun and exciting in the tub - all bets are off then (would there be water left then?); if the bodies have enough energy to continuously make more heat then eventually the bodies will raise the temperature. The body tries to produce heat when it senses a lowering of it's temperature - that's why people shiver.

One of the laws of thermodynamics is that warm bodies will try to warm objects near them. That's why if you sit next to a window (closed!) in the winter you get cold - your body is trying to warm the window.

Windsurfdog, you see how being a Techno Geek is; a pondering thought gets us to explain all the mysteries of life - See I told you a wealth of useless information!

[windsurfdog]

Windsurfdog, you see how being a Techno Geek is; a pondering thought gets us to explain all the mysteries of life - See I told you a wealth of useless information!

I wouldn't say useless at all, Vinman.....
Thanks to all that contributed both scientifically and humorously......I certainly agree with rocket, nhbeacon, stuart, salesdvl and others.....this forum is both informational AND enjoyable.  (Now if I could just understand how Wisoki's panties got so wadded.....)

[Chas]

I wouldn't say useless at all, Vinman.....
Thanks to all that contributed both scientifically and humorously......I certainly agree with rocket, nhbeacon, stuart, salesdvl and especially Chas.....this forum is both informational AND enjoyable.  (Now if I could just understand how Wisoki's panties got so wadded.....)
 

Perhaps he needs to run them through his dishwasher with the dry cycle off and no soap.

[SerjicalStrike]

Heat Loss - calculating the rate of heat loss due to conductance

Q = k A (Tb- Ta) / d, where

Q is the heat lost due to conduction
k is the thermal conductivity of the tub's insulation layer
A is the surface area through which the heat is being lost
Tb is the temperature of the tub
Ta is the temperature of the surrounding air
d is the thickness of the tub's insulating layer


WAAAY to tired to try and plug numbers in this morning.  Maybe after I get out in the fresh air on my first delivery.

[Top_Cat]

I regularly warm my tub water by having 8 friends with 103 degree fevers get into the tub and pee in the water.

Temp goes from 98 to 99 instantaneously. This makes it a HTP tub, I guess.

[Chas]

Heat Loss - calculating the rate of heat loss due to conductance

Q = k A (Tb- Ta) / d, where

Q is the heat lost due to conduction
k is the thermal conductivity of the tub's insulation layer
A is the surface area through which the heat is being lost
Tb is the temperature of the tub
Ta is the temperature of the surrounding air
d is the thickness of the tub's insulating layer


WAAAY to tired to try and plug numbers in this morning.  Maybe after I get out in the fresh air on my first delivery.

Then that would make it a linear relationship??

[windsurfdog]

Heat Loss - calculating the rate of heat loss due to conductance

Q = k A (Tb- Ta) / d, where

Q is the heat lost due to conduction
k is the thermal conductivity of the tub's insulation layer
A is the surface area through which the heat is being lost
Tb is the temperature of the tub
Ta is the temperature of the surrounding air
d is the thickness of the tub's insulating layer


WAAAY to tired to try and plug numbers in this morning.  Maybe after I get out in the fresh air on my first delivery.

Good stuff, serj....the only other consideration in actual heat loss then is the cover and how often it is removed.  Seems that your equation is based upon the cover being opened.  I would guess a cover closed equation with time and cover characteristics factored coupled with a cover open equation with time factored would get us close to a total heat loss amount over a given amount of time.  And like Chas and others pointed out, a wind factor should be considered as well.  Once again, trying to boil all of it down, if your equation is valid (and it sure looks good to me), it looks as if tub temperature is but a minor consideration in total heat loss which is a reflection of energy usage.  Food for thought.......

Top Cat said:

I regularly warm my tub water by having 8 friends with 103 degree fevers get into the tub and pee in the water.
 
Temp goes from 98 to 99 instantaneously. This makes it a HTP tub, I guess.

TC, I hope you don't mind when I say that I'll stick to my methods of tub energy consumption and you can have yours!  And please don't be offended should I decline your generous offer for a soak in your tub!

[windsurfdog]

Then that would make it a linear relationship??

Good question, Chas!

[Vinny]

Yes it does.

If it was log function it would involve a number to a power:

    n
  e

this is a log function!

Hey maybe being a Techno Geek isn't all that bad!

Vinny

[salesdvl]

Not only is this a fun and enjoyable forum but I actually am learning a few things too.  I hope that the otential spa customers enjoy this as much as we do.  

I meant to ask this before, Rocket, was that supposed to be "Potential" or "Oriental" ?

[stuart]

Here's the answer to the bodies in the water.

Ya gotta wonder how many times a statement like this  has been made by guys with names like Vinny...? Fugetaboutit!

[windsurfdog]

Ya gotta wonder how many times a statement like this  has been made by guys with names like Vinny...? Fugetaboutit!

ROFLMAO.........You're slaying me here.......