Coil Sizing for ammonia refrigeration system

[Ehtisham Ahmed]

Hi there,
I am student at a university and have been given a project of designing a ammonia refrigeration system having a blast freezer and a cold room. I have calculated all the load values and now need to calculate the surface area and length of the coil. How do i do that and please explain in simple terms as i am a student :p

[Peter_1]

You don't need to select a coil but an evaporator for both rooms.
Take 1st a catalog of a manufacturer of NH3 coolers and study first the selection criteria

[Ehtisham Ahmed]

But my project supervisor has asked me to find out the coil sizing. He asked to use the formula q=uadeltat and has already given me the delta t which is 5 and load for my cold room is about 17kw and blastfreezer is 40.11kw

[Magoo]

q = k factor x TD' K / thickness x 10 -3
k factor aluminium = 205w/m.K
1% carbon steel = 43 w/m.K
stainless steel = 16w/m.K
reference info from www engineers toolbox

[Ehtisham Ahmed]

i am a bit confused here, does this formula give me the thickness? and how do i find the length of the coil and surface area of the coil?