Question

A refrigerating system operates on the reversed Carnot cycle. The higher temperature of the refrigerant in the system is 35°C and the lower temperature is – 15°C. The capacity is to be 12 tonnes. Neglect all losses. 

Determine : 

(i) Co-efficient of performance. 

(ii) Heat rejected from the system per hour. 

(iii) Power required.

Answer 1

(i) T₁ = 273 + 35 = 308 K 

T₂ = 273 – 15 = 258 K 

Capacity = 12 tonne

(ii) Heat rejected from the system per hour :

Thus, heat rejected/hour = Refrigerating effect/hour + Work input/hour 

= 12 × 14000 + 32558 = 200558 kJ/h.

(iii) Power required :

Power required = \(\cfrac{Work input/hour}{60\times60}\) = \(\cfrac{32558}{60\times60}\) = 9.04 kW.