“…For the purpose of balancing the magnitude and unit differences, each output variable F was normalized as (Chiandussi et al, ): where p 1 , p 2 , and p 3 represents the input variable combination (air temperature, air velocity, and precooling time) and F n is the normalized value of the function. Different combinations of air velocity (0.58, 5, 10 m s −1 ), air temperature (0, −15, and −30°C) and precooling time (2, 4, and 6 hr) were considered.…”