1 ME421 Heat Exchanger Design Drain Water Heat Recovery System Project Presentation Group #5

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

3 PROBLEM DEFINITION Heat wasted during shower

4 AVAILABLE SOLUTIONS Gravity Film Heat Exchanger(GFX) Gravity Film Heat Exchanger(GFX)

5 PROPOSED SOLUTION Gasketed Plate Heat Exchanger: High Area/Volume Ratio High Area/Volume Ratio Low Cost compared to GFX Low Cost compared to GFX Easy to clean Easy to clean Flexible Design Flexible Design

6 APPLICATION DATA ParameterMagnitude Unit (SI) Hot Inlet Temperature 37°C Hot Outlet Temperature 23°C Cold Inlet Temperature 11°C Cold Outlet Temperature 25°C Cold Water Mass Flow Rate 0.2kg/s Hot Water Mass Flow Rate 0.2kg/s Hot Side Fouling Factor m.K/W Cold Side Fouling Factor m.K/W Maximum Allowable Pressure Drop 16bar

7 SOLUTION PROCEDURE Initial Assumptions: Steady state and steady flow processes Steady state and steady flow processes Negligible potential and kinetic energy change Negligible potential and kinetic energy change Equal inlet & outlet mass flow rates Equal inlet & outlet mass flow rates Single pass counter flow arrangement Single pass counter flow arrangement Safety factor Safety factor Plate dimensions based on MIT 522 [1] Plate dimensions based on MIT 522 [1] L v, L h, b, t, D p, β, Φ L v, L h, b, t, D p, β, Φ

8 SOLUTION PROCEDURE (Cont’d) Procedure: Iteration method to find N t Iteration method to find N t U A e N t G Re Nu h U U A e N t G Re Nu h U Rechecking of N t using calculated U Rechecking of N t using calculated U Pressure drop and pump power calculations Pressure drop and pump power calculations Comparison of ΔP limit and Δp calculated Comparison of ΔP limit and Δp calculated Pump power calculations Pump power calculations

9 RESULTS and DISCUSSIONS N t ranging between 3 and 11 Pressure Drop (Pa) Pressure Drop vs Number of Plates (N t )

10 RESULTS and DISCUSSIONS (Cont’d) β values : 30 °,45 °,50 °,60 °,65° Heat Recovery (W) Heat Recovery vs Chevron Angle (β)

11 RESULTS and DISCUSSIONS (Cont’d) Pump Power (W) N t ranging between 3 and 11 Pump Power vs Number of Plates (N t ) Pump Power (W)

12 RESULTS and DISCUSSIONS (Cont’d) β values : 30 °,45 °,50 °,60 °,65° Pressure Drop (Pa) Pressure Drop vs Chevron Angle (β)

13 RESULTS and DISCUSSIONS (Cont’d) ParameterMagnitude Number of Plates 7 Effective Heat Transfer Area m 2 Fouled Heat Transfer Coefficient 933 W/m 2.K Required Pump Work 24.5 W Heat Transfer Rate 1.17 x 10 4 W Net Heat Recovery 1.17 x 10 4 W

14 CONCLUSION Preheated. Preheated.