1. WASTE HEAT RECOVERY SYSTEM FROM DOMESTIC REFRIGERATOR
PRESENTATION ON
PROJECT REPORT
WASTE HEAT RECOVERY SYSTEM
FROM DOMESTIC REFRIGERATOR
BY: GROUP-II
FINAL YEAR
MECHANICAL DEPARTMENT
U.I.E.T C.S.J.M UNIVERSITY
KANPUR
PROJECT INCHARGE
Er. Arpit Srivastava
Dept. of Mechanical Engineering
UIET CSJM University
Kanpur

2. Waste Heat Recovery System From Domestic Refrigerator
SANDEEP KR. YADAV(272)
DEEPAK PATEL(253)
YASHWANT KR. JAISWAL(290)
KRISHNA PRAKASH(294)
MOHAMMAD ADIL(297)

3. CONTENTS Introduction Different recovery systems System Description
Design of Heat Exchanger
Design Of Oven
Fabrication And Assembly Works
Results
Conclusion

4. INTRODUCTION
In domestic refrigerator a part of heat gets wasted out from condenser
Wasted heat can be utilized
system is technically feasible and economically viable
Fig 1

5. DIFFERENT HEAT RECOVERY SYSTEM
HRSG in gas power plant or turbine
HVAC in steam power plant
WHRS in refrigeration plant

6. SYSTEM DESCRIPTION
Tested a WHRS and experimented to recover condensation heat from domestic refrigerator of 165 liter.
By suitably retrofitting the WHRS in the unit , considerable waste heat is recovered.
This heat is utilized for different purposes

7. SYSTEM DESCRIPTION SECTION “A”- HEAT EXCHANGER. SECTION “B”- OVEN.
SECTION “C”- PIPE
Fig 2

8. HEAT EXCHANGER
A heat exchanger is a device used to transfer heat between one or more fluids. The fluids may be separated by a solid wall to prevent mixing or they may be in direct contact.
They are widely used in space heating, refrigeration, air conditioning, power stations, chemical plants, petrochemical plants, petroleum refineries, natural-gas processing, and sewage treatment.
Fig 3

9. CLASSIFICATION OF HEAT EXCHANGER
On the basis of flow
(a) Parallel flow (b) Counter flow
Fig 4

10. WHY COUNTER FLOW IN WHRS?
The counter-flow heat exchanger has three significant advantages over the parallel flow design:-
The more uniform temperature difference between the two fluids minimizes the thermal stresses throughout the exchanger.
The outlet temperature of the cold fluid can approach the highest temperature of the hot fluid.
The more uniform temperature difference produces a more uniform rate of heat transfer throughout the heat exchanger.

11. DESIGN OF HEAT EXCHANGER
Applying heat transfer equation
heat transfer(1-2)= heat transfer(1-3)
+(1/( ℎ 𝑎𝑖𝑟 2𝜋 𝑟 3 𝑙)])

12. 3 = ln[ 𝑟 2 2.5 × 6 𝑟 2 0.5 × 𝑒 0.4 ] ln( 𝑟 2 2.5 ) r2 LHS RHS 2.8 3
Putting all known values , we get;
Now calculating the value of r2 by hit and trial method:-
3 = ln[ 𝑟 × 6 𝑟 × 𝑒 0.4 ] ln( 𝑟 ) r2
LHS
RHS
2.8 3
7.22
4.775
3.2
3.65
3.3
3.33
3.4
3.033

13. So r2=3.4mm
For Refrigerator of 165 liters capacity, given data from Kirloskar Ltd manual follows- [1]
Refrigerator cooling capacity (amount of refrigeration produced or heat extracted in refrigerator) =76 kcal/hr
= 76×4.187×1000×3600
= W
Power required running the compressor (work done on refrigerant) =
1/8 HP = 1/8×746 =93.25 W
Qcondensor = QEVOPORATOR + W COMPRESSOR =
= Watt

14. Assume efficiency of heat exchanger is 70%
So heat absorb by heat exchanger =QA
𝜂= 𝑄 𝐴 𝑄 𝐶𝑂𝑁𝐷𝐸𝑁𝐶𝐸𝑅
0.7= 𝑄 𝐴
QA= Watt
So heat receave by pipe through condenser is watt.

15. WHY OVEN? COMPLIMENT OF REFRIGERATOR LESS POWER REQUIRED
ECONOMICALLY VIABLE
Fig 5

16. Principle
The transient respond of the body can be determine by relating its rate of change of internal energy with convection exchange at the surface
Initially transient condition
Steady state later
Heat transfer through convection
[5]
Fig 6

17. Energy Supply Oven use low grade energy to work
It use the waste heat, which is release to atmosphere
The refrigerant circulates through tubes ("refrigerant lines") that travel throughout the oven.
This circulated refrigerant dissipate heat to the air inside oven

18. CONCEPTS & DESIGN
Since the temperature of air inside oven varies with time t initially
𝑻 𝒕 − 𝑻 𝒐 𝑻 𝒊 − 𝑻 𝒐 = 𝒆 −𝒉 𝑨 𝒔 𝒕 𝝆𝑽𝑪
𝐐(𝐭)=𝐡𝐀(𝐓𝐨−𝐓𝐢)[𝐭+ 𝝆𝑽𝒄 𝒉𝑨 𝒆 −𝒉 𝑨 𝒔 𝒕 𝝆𝑽𝑪 ]
Q= 𝝆𝑽𝑪( 𝑻 𝒕 − 𝑻 𝒊 )
𝑄=844.2 joules
T = 300 seconds
L = 0.6 meters

19. FABRICATION AND ASSEMBLY
Parts of domestic refrigerator are as follows-
Compressor
Modified Air cooled Condenser
Capillary Tube
Plate type Evaporator
Parallel type heat exchanger
Insulated pipe
Insulated Cabin
[4]

20. Fabrication of Insulated Cabin
5.2.1 Material Used: Galvanized Iron Sheet
5.2.2 Process used - Sheet metal forming.
Fig 7

21. Fabrication of Cabin
Inner box and outer box of insulated cabin are made up of Galvanized iron sheet. After defining dimensions, sheet metal working is performed. The cabin is painted by silver color.
Insulation material- here thermo Cole is used for insulation purpose and it is of 3.5cm thickness.
After forming all parts of cabin
it is assembled in well manner
as shown in
Fig 8

22. RESULTS The main aim is to use waste heat for domestic purposes.
Waste heat from condenser is utilised.
All above analysis results in utilisation of waste heat.
COP of refrigerator is also increased.

23. Actual COP of refrigerator
COPactual = 0.948
Improved COP of refrigerator
COPimproved= 0.98
Improvement in COP
= − x100
= 3.3%
COP improved varies than the actual calculated because of following errors.
1. Heat outleak while opening or closing the door cannot be exactly evaluated.
2. Actual COP is different than the value taken because the refrigerator is old.
3. Air may leak in or out because of old gasket.

24. CONCLUSION
Suitable heat recovery system can be designed and developed for every household refrigerator.
The experimentation has shown that such a system is practically feasible.
Technical analysis has shown that it is economically viable.
If this can be started from individual level then it can sum up and enormous effect can be obtained. Thus with small addition in cost if we recover and reuse the waste heat, then definitely we can progress towards energy conservation and simultaneously achieve our day today function.
In present situation where everybody in a home is moving out, this combination of refrigerator and food warmer is definitely a boom to efficient
house wife.

25. REFERANCES
[1] S.C.Kaushik, M.Singh., Feasibility and Design studies for heat recovery from a refrigeration system with a Canopus heat exchanger, Heat Recovery Systems & CHP, Vol.15(1995)
[2] P.Sathiamurthi, PSS.Srinivasan, Studies on waste heat recovery and utilization. Globally competitive eco-friendly technologies engineering National conference, (2005)39.
[3] P.Sathiamurthi, PSS.Srinivasan “Design and Development of Waste Heat Recovery System for air Conditioning Unit, European Journal of Scientific Research,Vol.54 No.1 (2011), pp
[4] C.P. Arora, Refrigeration and Air conditioning PHI Publications, 2010.
[5] Er.R.K.Rajput, Heat and Mass Transfer, 4e McGraw Hill Publication 2012
[6] Design and Development of Waste Heat of domestic refrigerator
[7] Frank P. Incropera and David P. Dewitt, Fundamentals of heat and Mass Transfer 5e, Wiley India edition, 2008.