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Thread: Ambient Temperature?

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    Default Ambient Temperature?

    Got a qusetion,
    I have an outdoor spa that i keep at a constant temp of 34 dg. when I go to use it I up the temp to whatever, lets say 38 dg (I like it hot).

    the system is computer controlled adn maintaines the temp at 34 dg independant of outside temp.


    Assuming winter temps


    My question, would it use more energy, apart from initial energy to heat water, to keep it constant at say 38 dg as compared to 34 dg?

    My thinking is that the fall in temp due to outside temp would be quicker at 38 dg than at 34 dg

    Am I wrong?

    thanks for looking in.

    porkop
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    Cool

    Quote Originally Posted by porkop View Post
    Got a qusetion,
    I have an outdoor spa that i keep at a constant temp of 34 dg. when I go to use it I up the temp to whatever, lets say 38 dg (I like it hot).

    the system is computer controlled adn maintaines the temp at 34 dg independant of outside temp.


    Assuming winter temps


    My question, would it use more energy, apart from initial energy to heat water, to keep it constant at say 38 dg as compared to 34 dg?

    My thinking is that the fall in temp due to outside temp would be quicker at 38 dg than at 34 dg

    Am I wrong?

    thanks for looking in.

    porkop

    G'Day Cobber,
    Without going into specific figures, the energy required to hold it above ambient is more if holding at 38C than at 34C, a well as the time to reheat.
    But you would have to calculate the usage and idle times as well as the gradient loss of energy when cooling.
    Whoa, a lot more involved in giving an answer than you envisage.

    Kindest Regards, " The Druid ".

    Last edited by beer4life; 18-05-11 at 09:06 PM.

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    Default

    Assuming winter temps the answer is yes.

    38 deg has more heat to give up than 34 deg, thats why hot water approaches freezing quicker than cold water.

    Cheers
    Casull

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    Default

    Thanks guys, just the info I was looking for.

    Probaly best to heat to required temp from 34 dg the few times a week than holding it higher all the time.

    Might have to sit in there with a few ale's thinking about this.

    Thanks again
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    That's why I run my spa on gas porkop.
    When you want to have a spa it will heat up from cold to hot in about 40 minutes.
    No need for a thermal cover.
    At the moment I'm using an old 2.4 meter mesh dish as the cover, keeps the leaves out yet still breathes

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    Quote Originally Posted by weirdo View Post
    That's why I run my spa on gas porkop.
    When you want to have a spa it will heat up from cold to hot in about 40 minutes.
    No need for a thermal cover.
    At the moment I'm using an old 2.4 meter mesh dish as the cover, keeps the leaves out yet still breathes
    I thought about gas butbthe extra expense along with building the gazebo that went around it, it's position in the back yard etc etc made it prohibitive.

    Stuck with electricity.

    Must say this though, the other morning, after the previous nights spa, set tempt 38 in the evening, had spa, set it back to 34, was still above 34 the next morning! Hadn't yet cooled down below the 0.5 dg threshold of setting that started the heat pump backup. Was a cold night also. Pretty happy with it's heat retention characteristics.

    And when heating, raises about one degree every half hour of so. Uses a small 80 watt circulator pump to move water around better than having to havebthe main pump runningnfor hours.
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    Quote Originally Posted by casull View Post
    Assuming winter temps the answer is yes.

    38 deg has more heat to give up than 34 deg, thats why hot water approaches freezing quicker than cold water.

    Cheers
    Casull
    How in the hell do you substantiate that ridiculous claim?



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    Unhappy Legionaires Disease.

    Quote Originally Posted by porkop View Post
    Thanks guys, just the info I was looking for.

    Probaly best to heat to required temp from 34 dg the few times a week than holding it higher all the time.

    Might have to sit in there with a few ale's thinking about this.

    Thanks again
    Legionnaires Disease,
    Oh Boy, you guys are sure flirting with your maker.



    Please desist so that I can continue to have the pleasure of your company.
    Kindest Regards, " The Druid ".

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    Quote Originally Posted by beer4life View Post
    Legionnaires Disease,
    Oh Boy, you guys are sure flirting with your maker.



    Please desist so that I can continue to have the pleasure of your company.
    Kindest Regards, " The Druid ".
    Hygiene is always important.
    That website has a vested interest in trying to sell you their products.
    So I'd take that with a grain of salt.
    How many people have you heard of catching legionnaires from spa use?
    That's not to say it's impossible but definitely not that likely

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    Quote Originally Posted by beer4life View Post
    How in the hell do you substantiate that ridiculous claim?


    I think you'll find this has been discussed here before. It stems from the fact that if you put two ice cube trays of water in the freezer at the same time - one with hot water, and one with room temp - the hot water one will freeze first. There is some technical reason for it that I dont know or understand (I think Trash will probably be able to explain) - but a quick google will probably reveal all the answers.

    Cheers.
    When I was a kid, I used to have an imaginary friend. I thought he went everywhere with me. I could talk to him and he could hear me, and he could grant me wishes and stuff too. But then I grew up, and stopped going to church.

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    Quote Originally Posted by Mods View Post
    I think you'll find this has been discussed here before. It stems from the fact that if you put two ice cube trays of water in the freezer at the same time - one with hot water, and one with room temp - the hot water one will freeze first. There is some technical reason for it that I dont know or understand (I think Trash will probably be able to explain) - but a quick google will probably reveal all the answers.

    Cheers.
    I remember that, wasnt it also disscussed on jjj with doctor karl?



    As to legionnaires, this is a real concern now

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    Quote Originally Posted by beer4life View Post
    How in the hell do you substantiate that ridiculous claim?


    Perhaps you should do some research first

    Cheers

    casull

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    Last edited by Hakko; 22-05-11 at 05:09 PM. Reason: wrong post

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