Design and fabrication of a Solar based Thermoelectric Refrigeration System. In the modern world global warming has become an important issue and all engineers of the world are trying to reduce global warming by inventing such devices and equipments which emit very low amount of gases and hence are less dangerous for life on Earth. Coefficient of performance of refrigerators having compressors decreases with decrease in capacity so for low capacity refrigerators, thermoelectric refrigerator is usually preferred in such cases. They have long life and require low maintenance. Solar thermoelectric refrigerator has been investigated in this project. The objective is to theoretically design a small scale solar based thermoelectric refrigerator compartment which operates on Peltier effect. This work details the analytical modeling of the key components of the thermoelectric refrigerator, which includes hot and cold side sinks, thermoelectric module, and solar panel. The effect of major parameters on the overall system performance is also mathematically studied. One cannot refuse the use of refrigeration systems in our daily life, refrigerators are used not only in kitchens but in shops and industries also. Compression refrigeration systems gives very good performance but refrigerants used in them are hazardous to the environment and human beings also because these refrigerants react with the ozone layer and cause depletion of ozone layer. Thermoelectric refrigerator is a refrigerator which is different from typical refrigerators that have compressors and it can substitute vapour compression refrigeration system for small scale applications and can reduce the number of chlorofluorocarbons. Methods of Refrigeration There are 2 methods of refrigeration  Cyclic Refrigeration   Non Cyclic Refrigeration 1.1.1 Cyclic Refrigeration System Cyclic refrigeration system is a system in which heat is removed from low temperature source and is rejected to high temperature sink with the help of external work. It is further divided into 2 types  Vapor Compression Cycle   Vapor Absorption Cycle 1.1.1.1 Vapor Compression Cycle Vapor Compression Refrigeration Cycle is almost 200 years old, and it is still in use. According to scientists and environmental engineers Vapor Compression 18 The cycle is environmentally harmful and inefficient but it is still applicable in the industrial sphere. In Figure 1.1 It can be seen that Vapor Compression Refrigeration Cycle involves four components: compressor, condenser, expansion valve/throttle valve and evaporator. It is a compression process; a compressor is used with the aim to raise the refrigerant pressure, as it flows from an evaporator. The high-pressure refrigerant from the compressor enters a condenser/heat exchanger where heat is removed after the heat removal process high-pressure fluid enters the expansion valve where fluid expands and is converted from high pressure to low-pressure fluid, this low pressure enter

2. Design and Fabrication of Solar
Thermoelectric Refrigeration System
Mechanical Engineering Dept. HITEC 2
GROUP MEMBERS
Syed Ali Bilal (16-ME-032)
Muhammad Saad (16-ME-060)
Sami Ullah (16-ME-108)
H. M Usman Nadeem (16-ME-140)
Supervisor: Dr. Abdul Waheed Badar
Co-Supervisor: Mam Attiya Sadiq

3. To Design Solar based
thermo electric
refrigeration system
To Fabricate Model
To Perform Experiments
Objectives
Design and Fabrication of Solar Thermoelectric Refrigeration System

4. • Design of Evaporator
• Design of Thermo Electric Module
• Design of Condenser
• Design of Solar PV Panel
Design
• Market Survey & Purchase Of Materials
• Model Manufacturing And Fabrication
• Assembling
Fabrication
• Detailed Performance Analysis
Experimentation
Design and Fabrication of Solar Thermoelectric Refrigeration System

5. Mechanical Engineering Dept. HITEC 5
Gantt Chart
Design and Fabrication of Solar Thermoelectric Refrigeration System

6. Step # 1
Cooling Load
Calculation
Step # 2
Modeling of
Evaporator
Step # 3
Design of
Thermoelectric
Modules
Step # 4
Modeling of
Condenser
Step # 5
Modeling of Solar PV
Panel
Step # 6
Procurement and
Fabrication
Step # 7
Installation of
Thermoelectric
Modules
Step # 8
Comparison of
Experimental &
Theoretical Results
Step # 9
Study Final Results
&
Report Writing
Flow Chart (Methodology)

7. Literature reviews
• Solid device that converts
electrical energy into
thermal energy
• Operates on Peltier effect
• Hot side is attached to a
heat sink while the cool
side goes below room
temperature.
Mechanical Engineering Dept. HITEC
7
Thermoelectric Module
Design and Fabrication of Solar Thermoelectric Refrigeration System

8. Mechanical Engineering Dept. HITEC 8
Model
Refrigerator
Design and Fabrication of Solar Thermoelectric Refrigeration System

9. Mechanical Engineering Dept. HITEC 9
Exploded View of Components
Fins
TEC Modules
Fan
Design and Fabrication of Solar Thermoelectric Refrigeration System

10. Module
hot side
Module
cold side
Inside Fan
cold side
fins
Hot side
fins
Fan
Inside Refrigerator
Wall
Section View

11. Mechanical Engineering Dept. HITEC 11
TEC Module
• Module = TEC-12706
• Maximum temperature
difference of 75oC assumed
60oC due to losses.
Tcold =
-10oC
Thot =
50oC
(1500 rpm
Design and Fabrication of Solar Thermoelectric Refrigeration System

12. Mechanical Engineering Dept. HITEC 12
Design of Cold Sink
• Heat Transfer For Freezing
Cooling Load
= 0.595 kW
Q֗total
Q֗total= 120.08 W
N = 11 Modules
• Heat Transfer For Cooling
Design and Fabrication of Solar Thermoelectric Refrigeration System

13.  Comparison
Mechanical Engineering Dept. HITEC 13
Evaporator Design Required Area (m2) No of Fins
Free Convection
(Without Fins ) 4.949 ----
Free Convection (With
Fins ) 2.4595 561
Forced Convection
(Without Fins ) 0.9327 ----
Forced Convection
(With Fins ) 0.915 194
Design of Cold Sink
Design and Fabrication of Solar Thermoelectric Refrigeration System

14. Mechanical Engineering Dept. HITEC 14
Design of Hot Sink
• Heat Transfer For Cooling
𝐐𝐇 = 𝐐𝐄 + 𝐖𝐓
QE =120.80 W
WT = 982.08 W
Cooling Load
= 1102.16 W
Q֗total
Design and Fabrication of Solar Thermoelectric Refrigeration System

15. Mechanical Engineering Dept. HITEC 15
Design of Hot Sink
Heat transfer for forced convection (with fins)
Design and Fabrication of Solar Thermoelectric Refrigeration System
𝑨𝒇𝒊𝒏 = 𝑷𝒍 + 𝑨𝒕𝒊𝒑 𝒏
𝑨𝒖𝒏𝒇𝒊𝒏 = 𝑨𝒏𝒐−𝒇𝒊𝒏 − 𝒏𝑨𝒕𝒊𝒑
Fan R
TH =600C
Tꝏ= 25 0C
Sopt

16. Mechanical Engineering Dept. HITEC 16
Design of Hot Sink
Heat transfer for forced convection (with fins)
Design and Fabrication of Solar Thermoelectric Refrigeration System
𝑨𝒇𝒊𝒏 = 𝑷𝒍 + 𝑨𝒕𝒊𝒑 𝒏
𝑨𝒖𝒏𝒇𝒊𝒏 = 𝑨𝒏𝒐−𝒇𝒊𝒏 − 𝒏𝑨𝒕𝒊𝒑
Sopt
𝐀𝐬= 1.311 𝐦𝟐
For number of fins;
𝐧 = 𝟑𝟎𝟕 𝐟𝐢𝐧𝐬

17. Mechanical Engineering Dept. HITEC 17
Design of Hot Sink
Heat transfer for forced convection (without fins)
Design and Fabrication of Solar Thermoelectric Refrigeration System
Dh
TH=600C
Tꝏ= 25 0C
𝐀𝐬= 2.1155 𝐦𝟐

18.  Comparison
Mechanical Engineering Dept. HITEC 18
Condenser Design Required Area (m2) No of Fins No of Modules
Forced Convection
(Without Fins )
2.1155 ---- 11
Forced Convection
(With Fins )
1.311 307 13
Design of Hot Sink
Design and Fabrication of Solar Thermoelectric Refrigeration System

19. Mechanical Engineering Dept. HITEC
• Q.
C = heat pumped by the module expressed in
watts
• α= seebeck co efficient in Vk-1
• R = resistance of thermoelectric module in
ohms
• Kt = thermal conductivity in Wm-1k-1.
Electrical Power Calculations
19
Design and Fabrication of Solar Thermoelectric Refrigeration System

20. Freezing Case Cooling Case
Q֗E = 595W Q֗E = 120.8W
α = 0.507 v/k α =0.049 v/k
R =1.96 ohm R=1.99 ohm
K=0.587 w/k K=0.541 w/k
Number of
modules=63
Number of
modules=11
Power=5596W Power=982.08W
COP =0.107 COP =0.135
Mechanical Engineering Dept. HITEC
Electrical Calculations Comparison
20
Design and Fabrication of Solar Thermoelectric Refrigeration System

21. Mechanical Engineering Dept. HITEC
Th : Temperature of hot side of module
Tc : Temperature of cold side of module
W: Power of one module
Number of modules
given by
COP =Q.
C /W
Electrical Power Calculations
21
Design and Fabrication of Solar Thermoelectric Refrigeration System

22. 1)
Declination
2) Sunrise
and Sunset
hour angle
3) Day
Length
4)
Irradiance
Solar Panel Calculations
Design and Fabrication of Solar Thermoelectric Refrigeration System

23. Design and Fabrication of Solar Thermoelectric Refrigeration System
Solar Panel Calculations
n is the day of the year
  23.45 sin [360(284+n365)]
Declination is given by the formula
s  cos-1( tan.tan )
Sunrise and Sunset hour angle is given by the
formula

24. Third step is to find Day Length or Sunshine
hours
In the fourth step Irradiance is found by using given
formula ( ≠s , value depends upon the time of
calculations)
Design and Fabrication of Solar Thermoelectric Refrigeration System
Solar Panel Calculations
N 
2s 15

25. • Solar panel calculations are done by taking data of shortest
day of year i.e 22 December
• =15 ( as the supposed time of calculations were 1 pm)
Design and Fabrication of Solar Thermoelectric Refrigeration System
Solar Panel Calculations
Declination  -23.45 degree
Sunrise and
Sunset hour angle
S 73.159 degree
Day Length N 9.754 hrs
Irradiance G0 731 W/m2

26. Design and Fabrication of Solar Thermoelectric Refrigeration System
Design Integration of PV Panel

27. Design and Fabrication of Solar Thermoelectric Refrigeration System
Design Integration of PV Panel

28. APPLIANCES
RATED
POWER
(W)
QUANTITY Watt
(W)
SUPPOSED
RUN TIME
TOTAL
POWE
R
(WH)
THERMOELECTRIC
MODULES
89.28 11 982.08 2Hrs 1964.16
LED
2 01 2 2Hrs 4
FANS
4 06 24 2Hrs 48
Total Wattage
1008.08
Power/Day
2016.16
Safety Factor
15 % 302.424
Net Power/Day
2318.58
4
Design and Fabrication of Solar Thermoelectric Refrigeration System
Design Integration of PV Panel

29. As we have,
For Battery Bank (DOD = 50 %) So we will multiply Amp
per day by 2
𝐴𝑚𝑝 𝑝𝑒𝑟 𝑑𝑎𝑦 =
𝑁𝑒𝑡 𝑝𝑜𝑤𝑒𝑟 𝑝𝑒𝑟 𝑑𝑎𝑦 × 𝐼𝑛𝑣𝑒𝑟𝑡𝑜𝑟 𝑙𝑜𝑠𝑒𝑠
𝑂𝑝𝑒𝑟𝑎𝑡𝑖𝑛𝑔 𝑉𝑜𝑙𝑡𝑎𝑔𝑒𝑠
𝐴𝑚𝑝 𝑝𝑒𝑟 𝑑𝑎𝑦 =
2318.584 × 1.1
12
= 212.536𝐴𝐻
Design and Fabrication of Solar Thermoelectric Refrigeration System
Design Integration of PV Panel

30. PV Generation = 20.1  5.5 = 110.55
No of PV modules = Required
Output/Available Input
No of PV modules = 212.536/ 110.55 2
PV Generation = PSH * PV Rating
Design and Fabrication of Solar Thermoelectric Refrigeration System
Design Integration of PV Panel

31. Operating Voltages 12V
Invertor Losses 1.1
Amp/Day 212.536 AH
Battery Bank 425.07 AH
Safety Factor 20% 85.014
Net Battery Bank 510.21 AH
Panel Amp 20.1
Amp/Day 110.55
No of Panel 1.92 or 2
Design and Fabrication of Solar Thermoelectric Refrigeration System
Design Integration of PV Panel

32. Design and Fabrication of Solar Thermoelectric Refrigeration System
Conclusion
• Thermoelectric Refrigerators are
environmental friendly and their COP is
enhanced using forced convection.
• As it can be seen from graph the relation
between cop and cooling load is linear. As we
increase cooling load our cop will increase and
vice versa.

33. Design and Fabrication of Solar Thermoelectric Refrigeration System
Conclusion
• Alteration in the connections of thermoelectric
modules ,converts the refrigerator into oven.
120.8 500 1000 1500 2000
COP=Q֗C/Power 0.135 0.5 1.018 1.5 2.036
0.135
0.5
1.018
1.5
2.036
0
0.5
1
1.5
2
2.5
COP=Q֗
C
/POWER
COOLING LOAD
Cooling Load vs COP
COP=Q֗C/Power Linear (COP=Q֗C/Power)

34. [1] Dr.S.Sreenatha Reddy, " Design and fabrication of thermo
electric refrigerator” IJTRSD, April 2019.
[2] Shen., Xiao., Chen & Wang., Investigation of a novel
thermoelectric radiant air-conditioning system. Journal of Energy
and Buildings, 59, 123–132, (2012).
[3] Yadav and Nirves., Review on Thermoelectric materials and
applications. International Journal for Scientific Research &
Development, 1,413-417, (2013).
[4] D.Astrain,J.G.Vian,M.Domınguez: “Increase of COP in the
thermoelectric refrigeration by optimization of heat dissipation”
Applied Thermal Engineering 23 (2003) 2183– 2200
34
Design and Fabrication of Solar Thermoelectric Refrigeration System
Reference
Mechanical Engineering Dept. HITEC

35. [5] Hongxia Xi, Lingai Luo, Gilles Fraisse: “Development and
applications of solar-based thermoelectric technologies”
Renewable and Sustainable Energy Reviews 11 (2007) 923
[6] Rong-Rong Hea, Huai-Yu Zhong, “Theoretical and
Experimental Investigations of Thermoelectric Refrigeration Box”
p. China, October 2017
[7] Dongarae V.K, Kinarae R.V, Parkar M.H, “ Design and
development of thermoelectric refrigerator”, April 2018
[8] Prof. D.S Vidhya,” Peltier Module for Heating and Coolling”,
March 2018
[9] Loii Kar Kin, Khairul Habib, “Analytic Investigation of
thermoelectric performance for cooling application”, June 2018
Mechanical Engineering Dept. HITEC
35
Design and Fabrication of Solar Thermoelectric Refrigeration System
Reference

36. 36

37. Extra Slides
Mechanical Engineering Dept. HITEC 37
Design and Fabrication of Solar Thermoelectric Refrigeration System

38. Mechanical Engineering Dept. HITEC 38
Design and Fabrication of Solar Thermoelectric Refrigeration System
Design of Evaporator
• Heat Transfer From Compartment
Walls
• Heat Transfer For Freezing
Q֗freezing= (m Cp ∆T)a.f + mhfg +
(m Cp ∆T)b.f
Q֗freezing= 0.5 kW
Tamb:
25oC
Ti: -
5oC
Qw
all Qfre
ez
Cooling Load
= 0.588 kW
Q֗total
Q֗total

39. Mechanical Engineering Dept. HITEC 39
Design and Fabrication of Solar Thermoelectric Refrigeration System
Design of Evaporator
• Heat Transfer For Cooling
Tamb:
25oC
Ti:
5oC
Qw
all Qcooli
ng
Cooling Load
Q֗total=
146.86 W

40. Mechanical Engineering Dept. HITEC 40
Design and Fabrication of Solar Thermoelectric Refrigeration System
Where
g = Gravitational Acceleration
Tf = Film Temperature
Ts=-
100C
Tꝏ= 25
0C
So
pt
Heat transfer for freezing case free
convection (with fins)
Design of Evaporator

41. Mechanical Engineering Dept. HITEC 41
Design and Fabrication of Solar Thermoelectric Refrigeration System
Design of Evaporator
For number of fins;
Ts=-
100C
Tꝏ= 25
0C
So
pt

42. Mechanical Engineering Dept. HITEC 42
Design and Fabrication of Solar Thermoelectric Refrigeration System
Design of Evaporator
=-100C
= 25 0C
Heat transfer for freezing case free
convection (without fins)
d
As=4.949 m2

43. Mechanical Engineering Dept. HITEC 43
Design and Fabrication of Solar Thermoelectric Refrigeration System
Design of Evaporator
Heat transfer for freezing case forced
convection (with fins)
Ts=-100C
Tꝏ= 25
0C
So
pt

44. Mechanical Engineering Dept. HITEC 44
Design and Fabrication of Solar Thermoelectric Refrigeration System
Design of Evaporator
For number of fins;
Ts=-100C
Tꝏ= 25
0C
So
pt