Surith Nivas M1, Vishnu Vardhan D2, Raam kumar PH3, Sai ......This paper outlines the implementation...

Copyright © 2013 SciResPub. IJOART

Photovoltaic Driven Dual Purpose Thermoelectric Refrigerator

for Rural India

Surith Nivas M1, Vishnu Vardhan D

2, Raam kumar PH

3, Sai Prasad S

4 , Ramya.K

5

1, 2, 3, 4&5 Department of Electrical and Electronics Engineering, RMK Engineering College, Chennai, India.

Email: [email protected], [email protected], [email protected], [email protected], [email protected]

ABSTRACT

This paper outlines the implementation of photovoltaic driven refrigerator cum heating system powered from solar panels

with a battery bank. Different from conventional refrigeration systems, thermoelectric refrigeration, based on the Peltier

effect, does not require any compressor, expansion valves, absorbers, condensers or solution pumps. Moreover, it does not

require working fluids or any moving parts, which is friendly to the environment and results in an increase in reliability. It

simply uses electrons rather than refrigerants as a heat carrier. Nowadays, thermoelectric refrigeration devices have a distinct

place in medical applications, electronic applications, scientific equipment and other applications, where a high-precision

temperature- -control is essential We demonstrate a Novel, Refrigeration cum Heater utilizing 3 Thermoelectric (Te) modules

mounted around a load cabinet. The Performance of this model is Experimentally Evaluated with an Aluminium cabinet.

The device is powered by a Non-conventional energy resource, here PV Cells. The cabinet can attain a temperature of about

8°C(min) till 200°C(max).The difference between the existing methods and this model, is that a thermoelectric cooling sys-

tem refrigerates without use of mechanical devices(Conventional Condenser fins and Compressor) and without refrigerant

too. Since the Peltier module is compact in size, a refrigeration or heating system can be designed according to the user’s

requirements (in desired size and shape).

Keywords : Photovoltaic system, thermoelectric refrigeration, peltier module, solar heater

1 INTRODUCTION

developed model of commercial thermoelectric

refrigertors with finned heat exchanger is established. The aim

of this chapter is to present some fundamental aspects of the

direct thermoelectric conversion. Thermoelectric systems are

solid-state heat devices that either convert heat directly into

electricity or transform electric power into thermal power for

heating or cooling. Such devices are based on thermoelectric

effects involving interactions between the flow of heat and

electricity through solid bodies. These phenomena, called See-

beck effect and Peltier effect, can be used to generate electric

power and heating or cooling. Solar energy is the most low

cost, competition free, universal source of energy as sunshine's

throughout. This energy can be converted into useful electrical

energy using photovoltaic technology .The steady state reduc-

tion of price per peak watt and simplicity with which the in-

stalled power can be increased by adding panels are attractive

features of PV technology.

Thermoelectric refrigeration replaces the three main work-

ing parts with: a cold junction, a heat sink and a DC power

source. The refrigerant in both liquid and vapor form is re-

placed by two dissimilar conductors. The cold junction (evap-

orator surface) becomes cold through absorption of energy by

the electrons as they pass from one semiconductor to another,

instead of energy absorption by the refrigerant as it changes

from liquid to vapor. The compressor is replaced by a DC

power source which pumps the electrons from one semicon-

ductor to another. A heat sink replaces the conventional con-

denser fins, discharging the accumulated heat energy from the

system. The difference between two refrigeration methods,

then, is that a thermoelectric cooling system refrigerates with-

out use of mechanical devices, except perhaps in the auxiliary

sense, and without refrigerant.

.

Fig 1 Block Diagram

A

International Journal of Advancements in Research & Technology, Volume 2, Issue 6, June-2013 ISSN 2278-7763

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Hardware Requirements:

Thermoelectric module (Tec1-12703HT)

PIC Microcontroller (16F877A)

Temperature sensor (LM35Dz)

Power storage battery (12v,7.2Ah)

Solar panel (12v,5w,750mA)

Relay (10A,24VDC)

Relay driver (ULN2003)

LCD

2 PRINCIPLE OF SOLAR POWER GENERATION

The principle of power generation behind the solar cells con-

sists of the utilization of the photovoltaic effect of semiconduc-

tors. When such a cell is exposed to light, electron-hole pairs

are generated in proportion to the intensity of the light. Solar

cells are made by bonding together p-type and n-type semi-

conductors. The negatively charged electrons move to the n-

type semiconductor while the positively charged holes move

to the p-type semiconductor. They collect at both electrodes to

form a potential. When the two electrodes are connected by a

wire, a current flows and the electric power thus generated

can be transferred to an outside application.

Fig 2 Principle Of PV Cell

3 THERMOELECTRIC MODULE

Heat absorbed at the cold junction is pumped to the hot junc-tion at a rate proportional to carrier current passing through the circuit and the number of couple. The semiconductor ma-terials are N and P type, and are so named because either they have more electrons than necessary to complete a perfect mo-lecular lattice structure (N-type) or not enough electrons to complete a lattice structure (P-type). The extra electrons in the N-type material and the holes left in the P-type material are

called "carriers" and they are the agents that move the heat energy from the cold to the hot junction. Heat absorbed at the cold junction is pumped to the hot junction at a rate propor-tional to carrier current passing through the circuit and the number of couple. Good thermoelectric semiconductor mate-rials such as bismuth telluride greatly impede conventional heat conduction from hot to cold areas, yet provide an easy flow for the carriers. In addition, these materials have carriers with a capacity for transferring more heat.

Fig 3 Dimensions of Peltier module

Sno Item Symbol Parameter

1. Input voltage max.

Vmax 15.4V

2. Max. current

Imax 3.3A

3. Max. heating temperature

Tmax 200°C

4. Min. cooling temperature

Tmin 6°C

Fig 4 Specifications Of Peltier Module

The high performance of the thermoelectric coolers, produced

allows us to increase the rate of cooling and reach a larger

temperature difference in relation to the environment. Ther-

moelectric coolers are optimized for source voltage 12V and

perform high cooling as well heating at low power consump-

tion

4 PIC MICRO CONTROLLER (16F877A)

PIC microcontroller is used to monitor heating and cooling inside the cabinet. It also controls the relay driver to change the mode(Heating mode or Cooling mode).

Fig 5 Crystal Oscillator Circuit


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The above circuit is the crystal oscillator that supplies frequen-cy to trigger the logic gates in microcontroller. The microcon-troller we use here has only 35 single-word instructions to learn .All single-cycle instructions except for program branch-es, which are two-cycle. Operating speed: DC – 20 MHz clock input DC 200ns instruction cycle. It has 10-bit, up to 8-channel Analog-to-Digital Converter (A/D). it has Analog Comparator module with - Two analog comparators Programmable on-chip voltage reference (VREF) module Programmable input multiplexing from device inputs and internal voltage refer-ence, Comparator outputs are externally accessible. Special features of this include 100,000 erase/write cycle Enhanced Flash program memory typical, 1,000,000 erase/write cycle Data EPROM memory typical, Data EEPROM Retention > 40 years, Self-reprogrammable under software control, In-Circuit Serial Programming™ (ICSP™) via two pins, Single-supply 5V In-Circuit Serial Programmingcomplete cycle, otherwise con-duction will overlap. It also has CMOS technologies that in-cludes following features of Low-power, high-speed Flash/EEPROM technology, Fully static design, Wide operat-ing voltage range (2.0V to 5.5V), Commercial and Industrial temperature ranges, Low-power consumption.

5 LM35 PRECISION CENTIGRADE TEMPERATURE

SENSORS

In this system the temperature prevailing inside the alumini-um cabinet is measured using LM35DZ sensor whose output is given to microcontroller to interpret it into Celsius values. Its general description includes the LM35 series are precision integrated-circuit temperature sensors, whose output voltage is linearly proportional to the Celsius (Centigrade) tempera-ture. The LM35 thus has an advantage over linear temperature sensors calibrated in ° Kelvin, as the user is not required to subtract a large constant voltage from its output to obtain con-venient Centigrade scaling. The LM35 does not require any external calibration or trimming to provide typical accuracies of ±1⁄4°C at room temperature and ±3⁄4°C over a full −55 to +150°C temperature range. Low cost is assured by trimming and calibration at the wafer level. The LM35’s low output im-pedance, linear output, and precise inherent calibration make interfacing to readout or control circuitry especially easy. It can be used with single power supplies, or with plus and mi-nus supplies. As it draws only 60 μA from its supply, it has very low self-heating, less than 0.1°C in still air.

Fig 6 LM35DZ circuit diagram

The LM35 is rated to operate over a −55° to +150°C tempera-

ture range, while the LM35C is rated for a −40° to +110°C range (−10° with improved accuracy). The LM35 series is available packaged in hermetic TO-46 transistor packages, while the LM35C, LM35CA, and LM35D are also available in the plastic TO-92 transistor package. The LM35D is also avail-able in an 8-lead surface mount small outline package and a plastic TO-220 package. 6 RELAY (10A, 24VDC)

Here Relay is used to reverse the supply to change the mode

i.e. to switch form cooling processes to heating vice versa. RW

Series Relay covers switching capacity by 10A in spite of min-

iature size to comply with user’s wide selection. RWH is ap-

proved C-UL & TÜV safety standard. The employment of

suitable plastic materials is applied under high temperature

condition and various chemical solutions. Complete protective

construction is designed form dust and soldering flux. If re-

quired, plastic sealed type is available for washing procedure.

12A at 120VAC for RW & 12A at 240VAC for RWH are UL ap-

proved. It is used for Domestic Appliances, Office Machines,

Audio Equipment, Coffee-Pots, Control units, etc.

Fig 7 Relay Circuit Diagram

7 RELAY DRIVER

Here relay driver is used to drive the relay by providing 0V to

switch on relay with 5V input from micro controller and vice

versa. The ULN2003 is a monolithic high voltage and high

current Darlington transistor arrays. It consists of seven NPN

Darlington pairs that features high-voltage outputs with

common-cathode clamp diode for switching inductive loads.

The collector-current rating of a single Darlington pair is

500mA. The Darlington pairs may be paralleled for higher

current capability. Applications include relay drivers, hammer

drivers, lamp drivers, display drivers(LED gas discharge),line

drivers, and logic buffers. The ULN2003 has a 2.7kW series

base resistor for each Darlington pair for operation directly

with TTL or 5V CMOS devices.


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Fig 8 Circuit Of Relay Driver ULN2003

8 LCD DISPLAY

A liquid crystal display (commonly abbreviated LCD) is a

thin, flat display device made up of any number of color or

monochrome pixels arrayed in front of a light source or reflec-

tor.

Fig 9 Interfacing Lcd With Pic 16f877a

It is often utilized in battery-powered electronic de-

vices because it uses very small amounts of electric power. In

this system LCD is used to display the current temperature

values in °C along with indication whether system is in cool-

ing mode or heating mode. It receives input regarding this

information from the micro controller.

9 WORKING OF THE MODEL

The source for our refrigeration cum heater system is renewa-

ble energy resource, here PV cells, are used. The power from

the solar panel is given to two batteries (12V,7.25A). From bat-

teries the power is delivered to peltier modules(3 nos) con-

nected in parallel each attached to their respective heat sinks.

Once the module gets the supply, it starts functioning (either

cooling or heating according to its respective mode).

The battery also supplies DC fan +fin (Heat Sink). PIC Micro-

controller receives 5V from the A.C power source i.e through

Step down transformer (230V to

12V),

Fig 10 Circuit Diagram

which monitors cooling and heating of the cabinet. Tempera-

ture sensor-LM35 series are precision integrated-circuit tem-

perature sensors, whose output voltage is linearly proportion-

al to the Celsius (Centigrade) temperature is kept inside the

cabinet, whose output is given to PIC microcontroller which is

programmed to interpret the voltage into Centigrade tempera-

ture values displayed in the LCD. In the cooling mode, PIC

microcontroller allows power to the module till the tempera-

ture reaches minimum temperature and it maintains the

same(once the temperature rises from the minimum tempera-

ture it restores the supply). For heating process, the supply

given to the modules are reversed with the help of relay.

Fig 11 Arial View Of The Model

Once the terminals are reversed, the heating process starts.

During heating, PIC microcontroller allows power to the

module till the temperature reaches maximum point and it

maintains the same (once the temperature falls below the max-

imum point the supply is restored) such that the temperature

is maintained inside the cabinet.


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Fig 12 Performance Analyses Between Existing

And Thermoelectric Model (cooling Graph)

The above graph depicts the plot of time in minutes and load

temperature in degree Celsius for thermoelectric model and

existing domestic model. From the graph, it is clear that ther-

moelectric model attains the minimum temperature about 8°C

in 40 minutes and maintains the same, where as the existing

model takes 1hour to attain the same. Further the thermoelec-

tric model maintains 8°C for nearly 5hours and then it starts

decreasing as shown. where as in existing model negative

temperature is achieved after 4 hours 10 minutes of time. This

is the only disadvantage of the thermoelectric model in which

the time taken to freeze is more.

Fig 13 Performance Analyses Between Existing

And Thermoelectric Model (Heating Graph)

This graph depicts the time taken to heat cabinet from 8°C.

This is the deviation observed from domestic refrigeration

system and thermoelectric refrigeration system. Thus both

Heating & Cooling are achieved using Peltier modules and it

is experimentally evaluated.

Table 1: Comparison Between Existing Heator And

Proposed Model

Table 2: Comparison Between Existing Refrigeration

Model And Proposed Model

Existing heater

system :

Thermoelectric heater :

Cannot be operated

during power outages.

Can be operated during

power outages as power is

given from PV cells.

Induction coil is

used for heating which

consumes large amount

of power.

Heat is derived from pel-

tier module which consumes

less power.

The cost of heating

water with electricity

can be quite large.

Electricity is not at all an

aspect here as heater works on

power obtained from PV cells

which saves maximum cost.

The system is prone

to corrosion.

Heat exchanger which is

Teflon coated is made of stain-

less steel and is corrosion free.

Existing refrigeration

model

Thermoelectric re-

frigeration model

Emits chlouro-fluoro

carbon. (CFC’s).

It is very Eco-

Friendly.

Uses refrigerant for

cooling.

It doesn’t require re-

frigerant

Life span with mean

time between failures is

87,600 working hours.

Long life with mean

time between failures is

200,000 hours.

Moving parts such us

compressors, condensers are

present.

No moving parts.


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10 TOTAL COST

Sno Components

name

Quantity Cost

1 Peltier module (tec1-

12703ht)

3 Rs.2102

($12.90/pcs )

2 Solar Panel(12v,5w) 1 Rs.500

($1.8/watt )

3 PCB 1 Rs.1075

4 Battery (12v,7.2Ah) 2 Rs.1600

(2x800)

5 Relay driver

(ULN2003)

1 Rs.20

6 DC fan +fin 3 Rs.375

(3x125)

7 Relay board 1 Rs.500

8 LCD 1 Rs.150

9 PIC 16F877A 1 Rs.130

10 Transformer (235V to

12V)

1 Rs.200

11 Temperature sensor

(LM35DZ)

1 Rs.32

12 Aluminium cabinet 1 Rs.425

Total cost Rs.7109

11 FUTURE SCOPE

To build a real time model replacing both air conditioner

and room heater in one system, i.e Thermo Electric Hot

And Cold Room Conditioner.

12 CONCLUSION

This paper has evaluated the working of Peltier module for producing effective heating and cooling placed inside an alu-minium cabinet. By using a temperature sensor inside the cab-inet surface, we get the corresponding temperature values for each instant which are displayed in an LCD (Liquid crystal display). The graph between temperature produced inside the cabinet against corresponding time interval are also presented and results are in line with the predictions. The advantages of the thermoelectric heater cum refrigeration on comparison with the existing heater and refrigeration system are elaborat-

ed. The physical dimensions and specifications of the Peltier module are presented. It is observed that the life span of ther-mo electric heater cum refrigeration system is more than twice the life span of existing conventional refrigeration or heater system. The principle of solar panel along with its specifica-tions and dimensions are displayed. As the future relies heavi-ly on Non conventional energy resources, the Solar powered thermoelectric heater cum refrigeration system will definitely be a large aspect in terms of energy saving capacity and the fact that the system is eco-friendly. The important aspect to be noted is that it is an one time investment and is maintenance free. 12 REFERENCES [1]Taylor, R.A.; Solbrekken, G.L. "Comprehensive system-level optimization of thermoelectric devices for electronic cooling applications", Components and Packaging Technologies, IEEE Transactions on, On page(s): 23 - 31 Volume: 31, Issue: 1, March 2008.

[2]Fukutani, K.; Shakouri, Ali "Design of Bulk Thermoelectric

Modules for Integrated Circuit Thermal Management", Com-

ponents and Packaging Technologies, IEEE Transactions on, On

page(s): 750 - 757 Volume: 29, Issue: 4, Dec. 2006

[3]Campbell, L.A.; Wagner, R.; Simons, R.E. "Analysis and

characterization of thermoelectric module and heat exchanger

performance in a hybrid system cooling application", Semi-

conductor Thermal Measurement and Management Symposium

(SEMI-THERM), 2011 27th Annual IEEE, On page(s): 48 – 53

[4]Solbrekken, G.L.; Yazawa, K.; Bar-Cohen, A. "Heat driven

cooling of portable electronics using thermoelectric technolo-

gy", Advanced Packaging, IEEE Transactions on, On page(s): 429

- 437 Volume: 31, Issue: 2, May 2008

[5]Sharp, Jeff; Bierschenk, Jim; Lyon, H.B. "Overview of Solid-

State Thermoelectric Refrigerators and Possible Applications

to On-Chip Thermal Management", Proceedings of the IEEE, On

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[6]Alley, Randy G. ; Soto, Marco A. ; Kwark, Leon ; Crocco, Paul ; Koester David; “Modeling and Validation of On-Die Cooling of Dual-Core CPU using Embedded Thermoelectric Devices” Semiconductor Thermal Measurement and Management Symposium, 2008. Semi-Therm 2008. Twenty-fourth Annual IEEE Digital Object Identifier: 10.1109/STHERM.2008.4509370 Publication Year: 2008 , Page(s): 77 - 82 [7]Snyder, G. Jeffrey ; Soto, Marco A. ; Alley, Randy G. ; Con-ner, “ Hot spot cooling using embedded thermoelectric cool-ers” Bob Semiconductor Thermal Measurement and Manage-ment Symposium, 2006 IEEE Twenty-Second Annual IEEE Digital Object Identifier: 10.1109/STHERM.2006.1625219 Publication Year: 2006 , Page(s): 135 – 143 [8]Koester; david ; Venkatasubramanian, Rama ; Conner, Bob ;


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Snyder, G. Jeffrey “Embedded thermoelectric coolers for semi-conductor hot spot cooling”Thermal and Thermomechanical Phenomena in Electronics Systems, 2006. ITHERM '06. The Tenth Intersociety Conference on Digital Object Identifier: 10.1109/ITHERM.2006.1645384 Publication Year: 2006 , Page(s): 491 – 496

[9]Simons, Robert E. Int. Bus. Machines, Poughkeepsie, NY, USA Chu, Richard C. Semiconductor Therma Embedded thermoelectric coolers for semiconductor hot spot cooling l Measurement and Management Symposium, 2000. Sixteenth Annual IEEE Page(s): 1 - 9 Meeting Date : 21 Mar 2000-23 Mar 2000 Conference Location : San Jose, CA Print ISBN: 0-7803-5916-X INSPEC Accession Number: 6635951 Digital Object Identifier : 10.1109/STHERM.2000.837055

[10]STEVENS, JAMES W. HEAT TRANSFER AND THERMOELECTRIC

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PUBLICATIONS MEETING DATE : 29 AUG 1999-02 SEP 1999 ISSN :

1094-2734 PRINT ISBN: 0-7803-5451-6 INSPEC ACCESSION

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Surith Nivas. M is currently pursuing

his B.E (Department of Electrical and

Electronics Engineering) in RMK Engi-

neering College, Anna University,

Chennai. He has received BEST STU-

DENT AMBASSADOR AWARD at

Waves’12 conducted by COLLEGE OF

ENGINEERING, GUINDY, Chennai.

His area of interest is Applied thermal Engineering, micropro-

cessor. Currently he is a member in Institute of Electrical and

Electronics Engineers.

Vishnu Vardhan. D is currently pur-

suing his B.E (Department of Electri-

cal and Electronics Engineering) in

RMK Engineering College, Anna Uni-

versity, Chennai.He is receiving Prime

Minister Merit scholarship for Ex ser-

vicemen wards, provided by Central

Government of India. His area of in-

terests includes Wind Energy forecast-

ing and analysis, Renewable Energy, Applied thermal Engi-

neering, Special Electric Machines. Currently he is a member

in Institute of Electrical and Electronics Engineers.

Raam Kumar.PH is currently pursuing his

B.E (Department of Electrical and Electron-

ics Engineering) in RMK Engineering Col-

lege, Anna University, Chennai. He is re-

ceiving central sector merit scholarship

from ministry of Human Resources(HR)

GOVERNMENT OF INDIA. His area of

interest is Applied thermal Engineering,

Transmission & Distribution. Currently he is a member in In-

stitute of Electrical and Electronics Engineers

Sai Prasad.S is currently pursuing his B.E

(Department of Electrical and Electronics

Engineering) in RMK Engineering College,

Anna University, Chennai. His area of in-

terest is Applied thermal Engineering, Spe-

cial Electric Machines. Currently he is a

member in Institute of Electrical and Elec-

tronics Engineers.

Ramya.K is an assistant professor in Elec-

trical and Electronics Engineering depart-

ment, RMK Engineering College,

Kavaraipettai, India. She obtained her M.E.

in Power electronics and drives from Jeru-

salem college of engineering ,Chennai, In-

dia. She has published 6 Technical papers

in National and International conferences proceedings. She

has 0.75 years of teaching experience. She has received

AWARD from the governor of TamilNadu, HIS EXCELLENCY

THIRU.SURJIT SINGH BARNALA for her UG Project in the

year 2010 through AIMO. She also received swamykannu best

project award for her PG project in the year 2012. She topped

Anna University Rank 1 in her PG. Her research interest in-

cludes areas of resonant converters, induction motor drives

and renewable sources. Ms K. Ramya is a member of Institute

of Electrical and Electronics Engineers.


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