An oil having a specific heat of 2100 J/(kg K) enters an oil cooler at 82°C at the rate of 2.5 kg/s. The cooler is a counterflow unit with water as the coolant, the transfer area being 28 m² and the overall heat transfer coefficient being 570 W/(m² K). The water enters the exchanger at 27°C. Determine the water rate required if the oil is to leave the cooler at 38°C.

GIVEN

• Counterflow heat exchanger - water cools oil
• Oil specific heat (c_po) = 2100 J/(kg K)
• Oil temperatures
• T_o,in = 82°C
• T_o,out = 38°C
• Oil flow rate (m_o) = 2.5 kg/s
• Transfer area (A) = 28 m²
• The overall heat transfer coefficient (U) = 570 W/(m² K)
• Water inlet temperature (T_w,in) = 27°C
• 

Transcribed Image Text:

Ol mo = 2,5 kg/s Ta,out = 38°C To,ln = 82°C. Tudn = 27°C Water