ME421 Heat Exchanger Design

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

description

ME421 Heat Exchanger Design. Drain Water Heat Recovery System Project Presentation Group #5. OUTLINE. Problem Definition Available Solutions Proposed Solution Application Data Solution Procedure Results and Discussions Conclusion. PROBLEM DEFINITION. Heat wasted during shower. - PowerPoint PPT Presentation

Transcript of ME421 Heat Exchanger Design

Page 1: ME421 Heat Exchanger Design

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ME421 Heat Exchanger Design

Drain Water Heat Recovery System

Project Presentation

Group #5

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OUTLINE

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

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PROBLEM DEFINITION

Heat wasted during shower

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AVAILABLE SOLUTIONS

Gravity Film Heat Exchanger(GFX)

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PROPOSED SOLUTION

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

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APPLICATION DATAParameter Magnitude 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 0.2 kg/s

Hot Water Mass Flow Rate 0.2 kg/s

Hot Side Fouling Factor 0.00005 m.K/W

Cold Side Fouling Factor 0.0000086 m.K/W

Maximum Allowable Pressure Drop 16 bar

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SOLUTION PROCEDURE

Initial Assumptions:

Steady state and steady flow processes Negligible potential and kinetic energy change Equal inlet & outlet mass flow rates Single pass counter flow arrangement Safety factor Plate dimensions based on MIT 522 [1] Lv, Lh, b, t, Dp, β, Φ

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SOLUTION PROCEDURE (Cont’d)

Procedure:

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 ΔPlimit and Δpcalculated

Pump power calculations

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RESULTS and DISCUSSIONS

Nt ranging between 3 and 11

Pre

ssur

e D

rop

(Pa)

Pressure Drop vs Number of Plates (Nt)

2 3 4 5 6 7 8 9 10 11 127.2 10

4

7.3 104

7.4 104

7.5 104

7.6 104

7.7 104

7.8 104

7.9 104

8 104

p t.c

p t.h

Nt

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RESULTS and DISCUSSIONS (Cont’d)

20 27.5 35 42.5 50 57.5 65 72.5 806 10

3

7.75 103

9.5 103

1.125 104

1.3 104

1.475 104

1.65 104

1.825 104

2 104

Qc W( )

Qf W( )

β values : 30 ° ,45 ° ,50 ° ,60 ° ,65°

Hea

t R

ecov

ery

(W)

Heat Recovery vs Chevron Angle (β)

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RESULTS and DISCUSSIONS (Cont’d)Pum

p P

ow

er

(W)

Nt ranging between 3 and 11

Pump Power vs Number of Plates (Nt)

Pum

p P

ow

er

(W)

2 3 4 5 6 7 8 9 10 11 1224.5

24.833

25.167

25.5

25.833

26.167

26.5

Wp

Nt

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RESULTS and DISCUSSIONS (Cont’d)

β values : 30 ° ,45 ° ,50 ° ,60 ° ,65°

Pre

ssure

Dro

p (

Pa)

Pressure Drop vs Chevron Angle (β)

20 30 40 50 607.3 10

4

7.35 104

7.4 104

7.45 104

7.5 104

p t.c

p t.h

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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 1.17x104 W

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CONCLUSION

Preheated .