PRESENTATIONON

PROJECT REPORT WASTE HEAT RECOVERY SYSTEMFROM DOMESTIC REFRIGERATOR

BY: GROUP-IIFINAL YEARMECHANICAL DEPARTMENTU.I.E.T C.S.J.M UNIVERSITYKANPUR

PROJECT INCHARGEEr. Arpit SrivastavaDept. of Mechanical EngineeringUIET CSJM University Kanpur

Waste Heat Recovery System From Domestic Refrigerator

SANDEEP KR. YADAV(272) DEEPAK PATEL(253) YASHWANT KR. JAISWAL(290)KRISHNA PRAKASH(294) MOHAMMAD ADIL(297)

CONTENTS

Introduction

Different recovery systems

System Description

Design of Heat Exchanger

Design Of Oven

Fabrication And Assembly Works

Results

Conclusion

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

DIFFERENT HEAT RECOVERY SYSTEM

• HRSG in gas power plant or turbine

• HVAC in steam power plant

• WHRS in refrigeration plant

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

SYSTEM DESCRIPTION

•SECTION “A”- HEAT EXCHANGER.

•SECTION “B”- OVEN.

•SECTION “C”- PIPE

Fig 2

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

CLASSIFICATION OF HEAT EXCHANGER

Classification- On the basis of flow

(a) Parallel flow (b) Counter flow

Fig 4

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.

DESIGN OF HEAT EXCHANGER

Applying heat transfer equation

heat transfer(1-2)= heat transfer(1-3)

45−40lnቀ𝑟2𝑟1ቁ2𝜋𝑘𝑟𝑒𝑓𝑙= ((45−30)/[ቌ lnቀ𝑟2𝑟1ቁ2𝜋𝑘𝑟𝑒𝑓𝑙ቍ+ቌ

lnቀ𝑟3𝑟2ቁ2𝜋𝑘𝑡ℎ𝑒𝑟𝑚𝑎𝑐𝑜𝑙 ∗𝑙ቍ +(1/(2])

Putting all known values , we get;

Now calculating the value of r2 by hit and trial method:-

r2 LHS RHS

2.8 3 7.223 3 4.775

3.2 3 3.653.3 3 3.333.4 3 3.033

3 =

So r2=3.4mmFor 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 = 88.392 W

Power required running the compressor (work done on refrigerant) =

1/8 HP = 1/8×746 =93.25 W

Qcondensor = QEVOPORATOR + W COMPRESSOR

=88.392+93.25=181.642Watt

Assume efficiency of heat exchanger is 70%So heat absorb by heat exchanger =QA

0.7

QA=127.149 WattSo heat receave by pipe through condenser is 127.149 watt.

WHY OVEN?• COMPLIMENT OF REFRIGERATOR• LESS POWER REQUIRED• ECONOMICALLY VIABLE

Fig 5

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

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

CONCEPTS & DESIGN

• Since the temperature of air inside oven varies with time t initially

Q= ()844.2 joulesT = 300 secondsL = 0.6 meters

FABRICATION AND ASSEMBLY

• Parts of domestic refrigerator are as follows- CompressorModified Air cooled CondenserCapillary TubePlate type EvaporatorParallel type heat exchanger Insulated pipe Insulated Cabin

[4]

Fabrication of Insulated Cabin 5.2.1 Material Used: Galvanized Iron Sheet

5.2.2 Process used - Sheet metal forming.

Fig 7

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

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.

• 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.

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.

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)665673.

• [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.102-110

• [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.