What I am looking for?

I am trying to find a source which is stating typical heat loss coefficient of a thermal energy storage or a buffer tank.


Most of the resources I've found so far, rather than stating the heat loss rate in the format of W/m^2k, they are stated in the form of normal standing loss values. This is not helpful in my case where I am using heat loss equations to estimate the possible losses.

Aim & objective

Aim The aim of my research is develop an open-source user friendly interface to characterize the output of low emission carbon sources.

Objective To characterize the heat loss rate of the storage unit considering the temperature of the water inside the tank.

Note: Formerly, one of the readers replied to a question of mine, that this platform is meant for non-professional individuals having troubles with their home system. I can say that I am a non-professional when it comes to commercial heating systems and I will not have any commercial gain from my project (through your advice).

Specific Question

Can you direct me to a source which is stating the typical heat loss coefficient (in W/m^2.K) values for thermal energy storage(s) (a.k.a buffer tank) deployed for residential or small commercial sites within the size range of 500 to 5000 liters.


1 Answer 1


The standby losses you see quoted should conform to a testing standard that would allow deriving the heat loss coefficient.

For hot water storage, I would expect typical tanks to have between 2 and 4 inches of foam insulation, so aged R-Values R10-R12 (hr*ft^2*F/btu)/RSI 1.76-2.11(K*m^2/W) on the low end and double that on the high end, with 2 inches being by far the most common.

  • Thank you for the recommendation. Is there any source that you provide so I can use and cite these numbers. Jun 12, 2016 at 19:33
  • What do you mean by low end and high end? Jun 14, 2016 at 11:27

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