How to calculate heat flux in a hot water tank

[chetanladha]

Hi.
I wish to calculate the heat flux on a bottom plate of a hot water tank. Would simply (m*c*t)/area give me the correct results.
Please help?

 

[edgepflow]

Is the bottom plate sitting on the ground or elevated? Is the tank insulated?

 

[chetanladha]

Thank you for your response.
Yes the tank is insulated,and sitting on ground.

Now the upper surface of plate is in contact with the fluid (hot water). How can i find the heat flux?

 

[edgepflow]

Thank you for your response.
Yes the tank is insulated,and sitting on ground.

Now the upper surface of plate is in contact with the fluid (hot water). How can i find the heat flux?

There are some nice "freeware" packages that will compute this. PM me if you are interested.

If you want to calculate it yourself, do this:

q = U A (T-water - T-outisde)

where,

q = heat loss
U = heat transfer coefficient
A = surface area
T-water = water temperature inside tank
T-outside = outside air temperature.

The heat transfer coefficient is given by:

U = 1 / [ 1/hi + twall/kwall + tins/kins + 1/ho ]

where,

hi = natural convection heat transfer coefficient on inside of tank
twall = tank wall thickness
kwall = tank thermal conductivity
tins = insultation thickness
kins = insulation thermal conductivity
ho = natural convection heat transfer coefficient on outside of tank

Let me know if you need any help figure these values out.