Determining the efficiency of an Upright Cabinet Evap Coil

[Kevin Breckle]

We are currently doing a number of test and thought I would throw out for some advise and opinions.

1) What is an Ideal TD for an 12ft Upright Cabinet to ensure it is efficient.
2) Best Place to measure from - Ie. After EV, Mid Coil and After Coil
3) Believing Mid Coil should be closet to zero
4) We using Hot Gas Defrost so we don't use a heater

[750 Valve]

There are a lot of details that you need to provide to answer the first question.

Assuming you are meaning designing a cabinet and not trying to optimise a current design's performance can you advise

- what is the temp you want to achieve?
- what stock will be stored in it or is it just for general use?
- is cabinet RH% important in the application?

The larger the coil surface the smaller the TD can be and therefore you can run a higher SST to achieve the temp which = better efficiency. A balance of capital outlay, ongoing energy consumption and RH to provide a general storage condition would see a 5K to 6K TD used as a design.

To truly work out capacity I would be using a flow meter in the liquid line and use the coil SST and suction line as it leaves the refrigerated space to take enthalpy measurements from.

I am not sure what you mean by point 3, are you referring to LMTD?