An adiabatic heat exchanger is used to heat cold water at 12°C entering at a rate of 4 kg/s by hot water entering at 95°C at rate of 2.5 kg/s. If the exit temperature of hot water is 50°C, the exit temperature of cold water is

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C_w=4.18 "kJ/kg-C"
Tcold_1=12 "C"
m_dot_cold=4 "kg/s"
Thot_1=95 "C"
Thot_2=50 "C"
m_dot_hot=2.5 "kg/s"
Q_loss=0 "kJ/s"
"The rate form of energy balance for a steady-flow system is E_dot_in = E_dot_out"
m_dot_hot*C_w*(Thot_1-Thot_2)=m_dot_cold*C_w*(Tcold_2-Tcold_1)+Q_loss 
"Some Wrong Solutions with Common Mistakes:"
Thot_1-Thot_2=W1_Tcold_2-Tcold_1 "Equating temperature changes of fluids"
W2_Tcold_2=90 "Taking exit temp of cold fluid=inlet temp of hot fluid"

An Adiabatic Heat Exchanger Is Used to Heat Cold Water