According to the pictures the model of Sun Frost is a R-4. The R-4 unit has a slightly larger refrigerator compartment (3.91 cubic feet) than the RFVB-134a refrigerator compartment (1.8 cubic feet). The Sun Frost R-4 is a refrigerator only model whereas the RFVB-134a has a freezer for making ice packs for vaccine carriers . Due to the lack of a freezer the R-4 uses (8 amp/hours/day at 70 degrees) and (12 amp/hours/day at 90 degrees). In this situation the R-4 is good idea. The R-4 is being used is a hospital and probably does not need to produce ice packs. The lack of the freezer provides more refrigerator capacity and reduces the energy use.