This document summarizes a senior design project to develop a cooling system for solar panels. The system aims to improve solar panel efficiency by preventing overheating. It uses flowing water within an insulated chamber behind the panels to conduct heat away. Testing showed the cooling system reduced panel temperatures by 16.9°C compared to an uncooled panel, increasing power output by 4%. While heat transfer to the water was lower than expected, the design demonstrates proof of concept. Potential improvements include using molded thermoplastics, adding insulation, and including fins to further transfer heat.

1. MEC 440
Senior Design: Solar
Photovoltaic Heat
Recovery
Group H
Jackie Chen Matthew Stevens
Luis Lituma Xie Zheng

2. The Problem

3. Abstract
 The efficiency of Solar Panels decreases as their
temperature increases, decreasing their overall power
output.
 The goal of this project is to improve solar photovoltaic
panel efficiencies by cooling them when they overheat
and recovering thermal energy for future use.

4. Existing Products
 Integra Global Solmaks
 Clean and cool down the solar panel with working fluid

5. Existing Products cont’d
 Solar panels with thermal glued cooling tube array
 A flat-plate photovoltaic solar panel, with an array of water-
cooling tubes affixed against the backside.

6. Existing Products cont’d
 Thin film PV module with conductive cooling envelope
 The cooling mechanism is accomplished through replacement of
existing laminate layers between thin film stack layers with a
conductive and reflective material, such as copper or aluminum.
Conductive cooling envelope

7. Product Design Specifications
 Core Features:
 Capacity to cool panels such that they do not exceed
designated temperature limit (45 degrees Celsius).
 Retrofittable with solar cell modules within the size of 24 x 18
inches.
 A well insulated outer frame to effectively recover heat through
the working fluid for re-use.
 An automated control system which actuates the cooling
system after temperatures exceed a designated maximum.

8. Product Design Specifications
Cont’d
 Safety Constraints and Design Standards
 The weight of the solar cell module and cooling system
combined should not exceed a standard uniform dead load
pressure of 5 lb/ft2.
 The combined system should be as similar in form to that of the
standard solar photovoltaic module in terms of shape as
possible, to minimize wind exposure. There should be between
3 and 6 inches of clearance between the module and the
rooftop surface.

9. Final Concept
Single winding rectangular duct
• Advantages
• Allows insulation of fluid
ducting, increasing total
thermal energy recovered.
• Reduces the wind load.
• More ducting surface
• Longer duration of contact
• Lengthwise pathing simplifies
construction
• Disadvantages
• May be moderately heavy and
unsuitable.
• Require machining for parts
• Require additional components
for centering and clamping.

10. SOLAR PANEL COOLING
SYSTEM ASSEMBLY

11. SOLAR PANEL COOLING
SYSTEM ASSEMBLY

12. Sub Assembly 1:
COOLING CHAMBER ASSEMBLY

13. Sub Assembly 1:
COOLING CHAMBER ASSEMBLY

14. Sub Assembly 2:
Panel Centering Supports

15. Bill of Materials
MACHINE PARTS
PART ASSEMBLY UNIT COST Q TOTAL
BOTTOM PLATE COOLING CHAMBER $115.21 1 $115.21
WALLS, DIVISIONS COOLING CHAMBER $12.18 9 $109.62
TOP CONDUCTING PLATE COOLING CHAMBER $268.38 1 $268.38
LONG CENTERING SUPPORTS PANEL SUPPORT $82.21 2 $164.42
SHORT CENTERING SUPPORTS PANEL SUPPORT $5.90 2 $11.80
SUBTOTAL $669.43
HARDWARE & EPOXY
DESCRIPTION ASSEMBLY UNIT COST Q TOTAL
10-32 x 1"L SCREWS PANEL SUPPORT $1.24 2 $2.48
JB WATER-WELD EPOXY COOLING CHAMBER $5.47 8 $43.76
SUBTOTAL $46.24
TEMPERATURE CONTROL SYSTEM
DESCRIPTION ASSEMBLY UNIT COST Q TOTAL
INTELLI-CIRCUIT CONTROLELR SOLAR PANEL COOLING SYSTEM $189.00 1 $189.00
SUBTOTAL $189.00

16. Bill of Materials
MATERIAL DESCRIPTION SUBTOTAL
MACHINE PARTS 669.43
HARDWARE & EPOXY 46.24
TEMPERATURE CONTROL SYSTEM 189.00
TOTAL 904.67

17. FEA using SolidWorks
𝑇 𝑤𝑎𝑡𝑒𝑟,𝑖𝑛 = 15°𝐶
𝑇𝑝𝑎𝑛𝑒𝑙 = 45°𝐶
𝑇𝐴𝑀𝐵 = 22°𝐶
𝑇 𝑤𝑎𝑡𝑒𝑟,𝑜𝑢𝑡 = 25°𝐶
@ 300 𝐺𝑃𝐻
Simulation Assumptions:
·Conditions similar to those in San Diego, CA on an August afternoon
·Steady fully developed water flow, entering at 15°C and 300 GPH.
·Negligible effects of convection on the panel and cooling system.
Summary of Results:
· Panel Temperature reaches a minimum of 42°C after 2 min. of
cooling
· Panel Temperature will not exceed maximum threshold for 28 min.
thereafter
· Temperature of bottom surface of copper plate increases with time
approaching
A maximum of near 42.5C after 10 minutes, indicating heat is in fact
being conducted
Away from the panel towards the water.
· An outlet water temperature of approximately 25°C, an increase of
10°C a result of the panel cooling process.

18. FABRICATION
COOLING CHAMBER ASSY
COOLING CHAMBER ASSY

19. FABRICATION
FINAL ASSY
SOLAR PANEL
COOLING SYSTEM ASSY

20. TESTING
SPECIAL THANKS TO THE ENERGY TECHNOLOGIES LAB STAFF
FOR ALL THEIR SUPPORT

21. TESTING

22. TESTING

23. Testing Results
y = -2E-05t2 + 0.0465t + 24.175
y = 2E-07t3 - 0.0002t2 + 0.0247t + 53.979
0
10
20
30
40
50
60
0 100 200 300 400 500 600 700 800
PanelSurfaceTemperature,T(°C)
time, t (seconds)
PANEL SURFACE TEMPERATURE VS. TIME
PANEL TEMPERATURE W/O COOLING PANEL SURFACE TEMPERATURE W/ COOLING
Uncooled temperature reaches its maximum at 54.4 C
Cooled temperature reaches its local minimum at 36.1 C

24. Uncooled Assembly
 Temperature rises 26.1 C from ambient.
 Power drops by 4.38% to 1.72 Watts.
23.9°C
27.6°C
30.3°C
31.1°C
33.6
36.9°C
36.4°C
41.9°C
43.3°C
44.2°C
45.3°C
46.9°C
48.3°C
°49.2C
1.72
1.73
1.74
1.75
1.76
1.77
1.78
1.79
1.8
1.81
0 100 200 300 400 500 600 700 800 900
SOLARPANELPOWEROUTPUT,P(W)
Time (s)
SOLAR PANEL POWER OUTPUT VS. TIME

25. Cooled Assembly
 Temperature drops 16.9 degrees to local min at 37.5 C.
 Power output increases by 4% at peak.
54°C
54°C
53°C
52.8°C
52.0°C
48°C
46°C
42°C
38°C
36.7°C
36.4°C
36°C
37°C
°38C
1.69
1.7
1.71
1.72
1.73
1.74
1.75
1.76
1.77
1.78
1.79
0 100 200 300 400 500 600 700 800 900
SOLARPANELPOWEROUTPUT,P(W)
Time (s)
SOLAR PANEL POWER OUTPUT VS. TIME

26. Results
 Verification of existing theory and successful proof of
concept.
 Successful increase in maximum power output and
efficiency in PV panel.
 Insufficient retention of heat in working fluid – increase
in about 3 degrees C at most.
 Weight of completed assembly with water can meet
PDS criteria but creates limit on roof coverage.

27. POTENTIAL IMPROVEMENTS
 CONSIDER USING MOLDED THERMOPLASTIC FOR COOLING CHAMBER
- This method for manufacturing was originally considered, but was never taken into consideration taken
associated lead times and costs associated with plastic molding processes. Using a molded design would
ultimately facilitate both the manufacturing and installation processes.
 USE INSULATION WITHIN THE CHAMBER
- While the system clearly demonstrates an ability to cool the surface of the solar panel within the desired range
of temperatures, our goal for the outlet temperature of the water for heating was not what initially expected. One
obvious culprit can be found in losses through the walls of the cooling chamber. A modification including the
addition of insulation would reduce the heat lost through the walls of the cooling system and increase the outlet
temperature of the water.
 THE ADDITION OF FINS FROM THE BOTTOM SURFACE OF THE COPPER
PLATE WHICH EXTEND TOWARDS THE MIDDLE OF THE COOLING
CHANNELS
- Another means of increasing the heat transferred to the water is the addition of conductive finned surfaces
extending from the copper plate and into the cooling chamber channels. Such fins could also be made of a
copper material, or any other suitable conductor.

28. SPECIAL THANKS TO:
 PROFESSOR’S GE AND ROSATI
 OUR ADVISOR, PROFESSOR DAVID J. JAE-SEOK HWANG
 THE SOLAR RACING TEAM
 PROFESSOR KEN TESTA, SEAN STOLL, AND GLENN MUSANO