non intrusive exhaust gas heat recovery system

0 downloads 0 Views 1MB Size Report
Bread Toaster. • Ambulance. • Safari rides. Hot. Box. Cold Water. Inlet. Hot Water Outlet. • To recover heat from exhaust pipe and used it to maintain items ...
NON INTRUSIVE EXHAUST GAS HEAT RECOVERY SYSTEM FOR AN AUTOMOBILE: A PRELIMINARY INVESTIGATION David Neihguk, Aravindh TR, Samir Rawte Mahindra & Mahindra Ltd.

Finding out what customers want without directly asking them

• “Some customers do carry food items on board while driving, especially in long trips.” - SUV customer survey at Mahindra Dealership in Chennai

• Most Taxi drivers driving at night frequently stops at highway tea stalls to have a cup of coffee to keep themselves awake for the trip.

The answer to this is “Hot Box” SAE INTERNATIONAL

Paper # 2013-01-2808

2

Objectives

• To recover heat from exhaust pipe and used it to maintain items temperature at 63°C (Food Safety Temperature Control, UK).

Expected Customer Benefits & Applications: • Hot Water • Milk, Tea, Coffee • Soup • Curries • Keep food warm • Instant food-Maggie • Pop Corn • Chapattis Application • Tourism Vehicles • Bread Toaster • Ambulance • Safari rides

SAE INTERNATIONAL

Hot Water Outlet

Hot Box

Cold Water Inlet

Paper # 2013-01-2808

3

Working Principle

Parallel flow concentric tube heat exchanger

Hot Box Unit

Exhaust Gas Flow

Hot Water Outlet

Cold Water Inlet

Inlet Port

Hot Box

Outlet Port Double Pipe Heat Exchanger Intermediate Exhaust Pipe

SAE INTERNATIONAL

Paper # 2013-01-2808

Flow Direction

4

Hot Box Circuit

Hot Water Outlet

Water Inlet

Hot water Inlet Return line

Hot Box

Hot Water Outlet

Cold Water Inlet

Swi tch

Pump

Heat Exchanger Unit

Hot Box

Heat exchanger

SAE INTERNATIONAL

Paper # 2013-01-2808

6

Optimization of heat exchanger length

Table : Optimization of Heat Exchanger length

S.No

Length (mm)

Volume (L)

Temperature (o C)

1

500

4.4

208

2

450

4

198

3

400

3.5

186

4

350

3.1

173

5

300

2.6

158

6

250

2.2

140

7

200

1.7

121

8

150

1.3

98

9

100

0.8

73

Figure : Optimization of length of Primary Heat Exchanger SAE INTERNATIONAL

Paper # 2013-01-2808

7

Simulation results

Fig: Contours temperature variation in Water regime & Exhaust Gas

SAE INTERNATIONAL

Paper # (if applicable)

Fig: Exhaust Pipe temperature

8

Simulation results

Graph: Comparison of Outlet water temperature(K) SAE INTERNATIONAL

Paper # (if applicable)

9

Testing Results

Table : Results of Static testing T1 T2 T3 T4 T5

Initial 34 34 31 31 31

After 15 minutes 95 90 37 34 39

Table 3. Results of Dynamic testing at 10 kmph

T1 T2 T3 T4 T5

Initial 36 38 36 33 36

Final 121 111 45 35 50

Table 4. Results of Dynamic testing at Highway Driving

where T T1 T2 T3 T4 T5

Temperature in degree Celsius Exhaust gas temperature before heat exchanger Exhaust gas temperature after heat exchanger Hot Box temperature Cold water temperature Hot water temperature

SAE INTERNATIONAL

Paper # 2013-01-2808

T1 T2 T3 T4 T5

Initial 36 38 36 31 36

Final 348 336 82 33 94

10

LMTD

The Log mean temperature difference for a parallel flow double pipe heat exchanger is given by equation:

The log mean temperature difference for the three cases are as given below

SAE INTERNATIONAL

Testing Condition

LMTD

Static At 10 kmph

55.85 72.75

Highway driving

276.89

Temperature measurement at highway driving condition

400

Temperature in degC

350 300 250 T1

200

T2 T5

150

1st Stop

100

T3

2nd Stop 65 deg C Hot Box Temperature

50 0 0

1000

2000

3000

4000 5000 Time in Seconds 45 minutes for Data logger preparation 48 minutes for Hot Box to reach and Security Clearances 65 deg C despite two stops in between

Results T1 T2 Initial 117.27 112.12 Maximum 347.87 335.82

SAE INTERNATIONAL

T3 35.66 82.27

T4 32.78 32.78

T5 LMTD 32.78 93.87 277.79

Paper # 2013-01-2808

6000

7000

8000

Abbreviations T1= Exhaust Gas Temperature before Heat Exchanger T2= Exhaust Gas Temperature after Heat Exchanger T3= Hot Box Temperature T4= Cold Water Temperature T5= Hot Water Temperature 12

Proof of Concept demonstrated in SUV

• Hot Box Temperature (T3) of 82 deg C and Hot Water Temperature (T5) of 94 deg C achieved within less than 30 minutes of driving in Highway. • T1 and T2 are Exhaust Gas Temperature at Inlet and Outlet respectively

SAE INTERNATIONAL

Paper # 2013-01-2808

13

Conclusions

• Adequate amount of heat energy can be recovered from the exhaust gas. • Further work needs to be done including the control strategies to regulate the hot box temperature. • Design of components to make the water fit for drinking is a challenge.

SAE INTERNATIONAL

Paper # 2013-01-2808

14

THANK YOU

SAE INTERNATIONAL

Paper # 2013-01-2808

15