Frigoscandia spiral freezer

[ASAD]

Hi to all,

A client of ours, has a Frigoscandia spiral freezer.

Model – GC 400-06-25-06 NS CCR.

The evaporator is a flooded type.

Working conditions: (-40) / 45.

refrigerant- R-22.

A rack/stand, with two handbell screw compressors: RC12 + RC11.

Attached are two sketches that describe the system.

I have a few questions regarding the system:

1. We want to change the refrigerant (R-22) to a different type, which would you recommend?

2. How would you call the tank that is by the evaporator (figure 1)?

3. The valve that is located after the solenoid (figure 2) is a globe type. It is not a regulation valve. When the solenoid valve is opened, all the refrigerant runes to the evaporator, without going through the expansion valve (Danfoss TEX-2) of the compressors economizers. (the easy way), which means we are losing capacity.

What do you think about that?

4. We would like to increase the capacity and we thought about cooling the liquid that enters the evaporator by adding a heat exchanger.

We thought about doing that in two different ways:

a. With an external cooling unit, by cooling the liquid down to (-40).

b. Like an economizer – the liquid will cool down by itself.

What do you think about that?