# A water cooler of storage capacity 120 litres can cool water at constant rate of P

A water cooler of storage capacity 120 litres can cool water at constant rate of P In a closed circulation system (as shown schematically in the figure), the water from the cooler is used to cool an external device that generates constantly 3 kW of heat (thermal load). The temperature of water fed into the device cannot exceed 30°C and the entire stored 120 litres of water is initially cooled to 10°C. The entire system is thermally insulated. The minimum value of P (in watts) for which the device can be operated for 3 hours is :

(Specific heat of water is 4.2 kJ kg–1 K–1 and the density of water is 1000 kg m–3)

(A) 1600

(B) 2067

(C) 2533

(D) 3933