Al_eng
Mechanical
- Jul 22, 2020
- 6
Hello I'm looking for advice on if I'm approaching this problem in the correct way whilst trying to keep it simple.
I'm designing a rectangular stainless steel cooling tank which will be located outside with no insulation.
I have 170kg/hr of water at 90°C entering a tank under gravity flow, I need the water leaving the tank to be less than 60°C (also under gravity flow).
I've made a guess on the dimensions of the tank to give a starting point to the calculations. Area of water in contact with the tank walls of 0.675m^2 and a wall thickness of 6mm
Outside mean average summer temperature 14°C
I've calculated the heat loss from the tanks walls:-
q = 15 W/mK x 0.675m^2 x [ (60°C - 14°C) / 0.006m ] = 77.6 kW
I've calculated the heat gain from the hot water entering:-
Q = 170kg/hr x 4190 J/Kg °C x (90°C - 60°C) = 5.9 kW
As the heat loss from the tank is more than the heat gain am I right in saying the temperature of water leaving the tank will be less than 60°C?
I know there's a lot of factors I haven't taken into consideration to try to keep it simple such as lower night temperatures, wind, heat from the sun (tank positioned in a shaded location)
I was also planning designing the tank with baffle plates to promote free mixing to help with the assumption that the contents of the tank will reach a temperature equilibrium.
Thanks in advance
I'm designing a rectangular stainless steel cooling tank which will be located outside with no insulation.
I have 170kg/hr of water at 90°C entering a tank under gravity flow, I need the water leaving the tank to be less than 60°C (also under gravity flow).
I've made a guess on the dimensions of the tank to give a starting point to the calculations. Area of water in contact with the tank walls of 0.675m^2 and a wall thickness of 6mm
Outside mean average summer temperature 14°C
I've calculated the heat loss from the tanks walls:-
q = 15 W/mK x 0.675m^2 x [ (60°C - 14°C) / 0.006m ] = 77.6 kW
I've calculated the heat gain from the hot water entering:-
Q = 170kg/hr x 4190 J/Kg °C x (90°C - 60°C) = 5.9 kW
As the heat loss from the tank is more than the heat gain am I right in saying the temperature of water leaving the tank will be less than 60°C?
I know there's a lot of factors I haven't taken into consideration to try to keep it simple such as lower night temperatures, wind, heat from the sun (tank positioned in a shaded location)
I was also planning designing the tank with baffle plates to promote free mixing to help with the assumption that the contents of the tank will reach a temperature equilibrium.
Thanks in advance
