Evaporator Design

This is too much like homework for me.

You could contact:

VOGT TUBE-ICE MACHINES

But, they may not want to show a potential competitor their wares.

How come in this age of environmental awareness and concern,refrigerants such as R22, which havent been used in any new manufactured refrigeration equipment in Europe for some years now because of its environmental impact,are still being considered in other parts of the world?

There are alternatives.........more efficient,less stress on the components fitted,and you will be doing your bit as an engineer to contribute to the above.