An ice skating rink is located in a building where the air is at T_air = 20°C and the walls are at T_w = 25°C. The convection heat transfer coefficient between the ice and the surrounding air is h = 10 W/m² · K. The emissivity of ice is ε = 0.95. The latent heat of fusion of ice is h_if = 333.7 kJ/kg and its density is 920 kg/m³.

(a) Calculate the refrigeration load of the system necessary to maintain the ice at T_s = 0°C for an ice rink of 12 m by 40 m.

(b) How long would it take to melt d = 3 mm of ice from the surface of the rink if no cooling is supplied and the surface is considered insulated on the back side?

Transcribed Image Text:

Refrigerator load Tw = 25°C Tair = 20°C h = 10 W/m².K grad ¿conv Insulation mfu T, = 0°C - Control volume Ice