# The Effect of Heat Sink Properties on Solar Cell Cooling Systems
## 5 Tendency of Heat Sink Properties  
The heat sink material affects the performance of solar cells. Furthermore, the high working temperature of solar panels affects their performance [27]. Heat resulting from solar radiation is released into the environment using a heat sink [11]. Heat dissipation by the heat sink is influenced by the value of its thermal conductivity. Furthermore, the contact area affects the amount of heat generated. Increasing the number of fins increases the contact area with the air. Figure 4 shows the lower working temperature as the number of fins increased using Cu-Al materials. Each variation of the experiment results in a different level of efficiency. Increasing the working temperature resulted in a decrease in solar panel efficiency. The use of 15 fins resulted in the lowest working temperature of 55.4 \({}^{\circ}\)C. The highest working temperature was 64.6 \({}^{\circ}\)C which result from the use of 15 fins. Using 10 fins resulted in a temperature that was 2.1 \({}^{\circ}\)C lower than that achieved with 5 fins. Fifteen fins achieved a working temperature that was 1.2 \({}^{\circ}\)C lower than that achieved with 10 fins. The addition of 5 fins provided a higher impact than the changes made to the material used. The results of the experimental method and the simulation of the temperature decrease trend are similar. Figure 5 shows the comparison between the modeling trend and the experimental trend. Figure 4: Relationship of solar radiation intensity to working temperature. Figure 3: Experimental process: (**a**) Laptop, (**b**) Adam data logger, (**c**) solar power meter, (**d**) amperemeter and voltmeter, (**e**) variable resistor, (**f**) photovoltaic (PV) with heat sinks, (**g**) PV without heat sinks, (**h**) anemometer, and (**i**) fan blower. Increasing the cooling capacity increased the efficiency of solar panels. The efficiency of solar panels with fins can be seen in Figure 6. The greater the number of fins used, the better the cooling performance obtained. As a result, good cooling increased the efficiency. A change in efficiency occurred when 5 and 10 fins increased efficiency by 0.61%. The use of 15 fins was only able to increase efficiency by 0.21%. This difference in increase can be caused by differences in the _Isc_ and _Voc_ values in the temperature range of 55-61 \({}^{\circ}\)C. The addition of the number of fins may cause turbulence of the airflow that occurs in the heat sink. This turbulence increases the volume of air flowing on the surface of the heat sink. Contact between the fins and air causes heat dissipation. Figure 7 shows that the greater the number of fins, the more heat dissipation occurs. Heat dissipation is affected by the cross-sectional area of the heat-releasing component. The area in contact with air increases with the rise in the number of fins. The constant increase is due to the smaller air contact gap that occurs. As a result, the effect of the addition of fins is similar to that of increasing the thickness of the base, which leads to poor heat dissipation. Figure 5: Experimental vs. modeling. Figure 6: Graph of the relationship between working temperature and efficiency. Increasing from 5 to 10 fins has a better effect than increasing from 10 to 15 fins. This is because increasing the number of fins increases the contact area with air. However, when the gap between the fins is narrow, air passes too quickly over the surface of the fins. The shorter the contact, the less effective the heat dissipation. In addition to the number of fins, the material used also affects cooling performance. Research on the use of materials was conducted using 10 fins, where the improvement from 5 to 10 fins was greater than that of the increase from 10 fins to 15 fins. Figure 8 shows the heat sink with Cu-Cu material has the lowest temperature of 53.7 \({}^{\circ}\)C. The highest temperature was obtained in Al-Al material with a temperature of 59.0 \({}^{\circ}\)C. The conductivity value of copper is higher than that of aluminum.