Author Topic: Reverse use of heating coil in Solar hot water tank  (Read 1662 times)

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Offline Sunsheat

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Reverse use of heating coil in Solar hot water tank
« on: March 19, 2013, 08:37:10 PM »
I am working on plans for a new hot water system utilising Solar panels and a Wet back wood fire.
Unlike  one of the  "conventional" systems of putting one or both external heating water systems through a closed coil inside the tank, the concept is to open circuit the solar and wetback water through the tank and heat  the house water through a coil in the tank.
Has any one had experience of this system and can you offer advice for specifying the setup?
The system will probably use a custom built copper tank of approx 250 - 270 L and would operate at around 40 kpa .. . .
thanks . . .


Offline Plumber

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The name of the system or "hot water cylinder" your referring to is called "elephant" These systems were installed many years ago for various reasons including being able to run a radiator on the low pressure side, disadvantage is the temperature drop you will get when running the tap (shower) for a longer period of time (especially these days when everything is medium to mains pressure), temperature fluctuation plus the heat transfer time is very noticeable if your heat source cant keep up heating the large body of water on demand. It's critical to get the right cylinder with the correct heat exchanger as modern models have the heat exchanger placed for the ideal reverse function. For the correct application though, this system is brilliant. By the way im not sure where it got its name "elephant" from (I can only guess) so if anyone can shed some light on that, it would be greatly appreciated.  ::)
Please note that the advice I am giving is only my opinion and not necessarily a fact.  Please refer to our terms and conditions.

Offline integrated

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Re: Reverse use of heating coil in Solar hot water tank
« Reply #2 on: March 19, 2013, 09:32:18 PM »
the property and client need to have there energy need modelled, that will determine store size and heat exchanger requirements - as well as solar absorbtion requirements and boiler size

there are solar/consultancy companies in the business section that will be willing to help on specific system design

good luck!!

Offline Smith Titos

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Re: Reverse use of heating coil in Solar hot water tank
« Reply #3 on: April 18, 2013, 08:17:41 PM »
seems to be an interesting project best of luck to you

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