A comparison is made between an ice-slurry solution with different inlet ice mass fractions and an R404a refrigerant utilised in an evaporator with constant heat power and fixed geometry. The comparison is obtained using a parameter that represents the ratio between the total real entropy variation and the exchanged heat. This parameter, introduced by Grazzini and Ferraro (2000), shows that an ice-slurry solution is better than an R404a as refrigerant fluid, when considering a particular heat exchanger. The heat exchanger used is of a finned tube type with an in-line tube bank. Results show that with the same heat power ice-slurry entropy variation is lower than that given by R404a.