How does it work?  
The basic principle of a transport refrigeration unit is largely equal to an air conditioner. Only some components are made differently.

Transport refrigerators are used to transport temperature sensitive products or perishable goods. Like food stuff, flowers, medicines etc.

Vans are therefore often equipped with transport refrigerators. ALR NV has a large list of compressor brackets and a few reliable brands of transport refrigerators, we can install a transport refrigerator in most delivery vans or transport vehicles.
Click to enlarge.

Click to enlarge.