ME421 Heat Exchanger Design Drain Water Heat Recovery System Project Presentation

OUTLINE Problem Definition Available Solutions Application Data Solution Procedure Results and Discussions Conclusion

Heat wasted during shower PROBLEM DEFINITION Heat wasted during shower

AVAILABLE SOLUTIONS Gravity Film Heat Exchanger

APPLICATION DATA Parameter Magnitude Unit (SI) Hot Inlet Temperature 37 °C Hot Outlet Temperature 23 Cold Inlet Temperature 11 Cold Outlet Temperature 25 Cold Water Mass Flow Rate 0.2 kg/s Hot Water Mass Flow Rate Hot Side Fouling Factor 0.00005 m.K/W Cold Side Fouling Factor 0.0000086

SOLUTION PROCEDURE Initial Assumptions: Steady state and steady flow processes Plate dimensions based on MIT 522 [1] Negligible potential and kinetic energy change Equal inlet & outlet mass flow rates Single pass counter flow arrangement Safety factor

SOLUTION PROCEDURE (Cont’d) Iteration method to find Nt U Ae Nt G Re Nu h U Rechecking of Nt using calculated U Pressure drop and pump power calculations Comparison of ΔPallowable and ΔPcalculated

RESULTS and DISCUSSIONS Cleaned and Fouled Heat Transfer Rates Chevron Angle ranging between 30° - 70°

RESULTS and DISCUSSIONS (Cont’d) Parameter Magnitude Number of Plates 7 Effective Heat Transfer Area 1.463 m2 Fouled Heat Transfer Coefficient 933 W/m2.K Required Pump Work 24.5 W Heat Transfer Rate 1.17x104 W Net Heat Recovery

WELL DONE