Electricity amount generated by photovoltaic panels decreases with increase in their surface temperatures. Therefore, various methods are used to decrease the surface temperatures of photovoltaic panels. In recent years, as one of these methods, there are some studies on using thermoelectric coolers. In this study, a photovoltaic panel is cooled by a thermoelectric cooler, and effect of decrease in surface temperature with the result of this cooling on performance is investigated theoretically and experimentally. Experiments are conducted for two different days and their results are compared with each other. By using the thermoelectric cooler, average temperature decreases are obtained to be 3.1 degrees C and 4.9 degrees C for two different days. Also, increases in energy and power generation with the rates of 7.3% and 6.7% are occurred. In this way, average rates of power increase for unit temperature drop are found to be 2.3% and 1.2%. In addition, average rates of performance increasement for unit temperature drop are around 2.0% and 1.1%. Theoretical surface temperature and power generation values obtained from photovoltaic panel with a thermoelectric cooler that was modelled thermodynamically are compared with measured data, and consentient results are achieved. Modelling is extended by using hourly typical meteorological data. It is seen that the difference between surface temperatures of the panels reaches up to 12.7 degrees C in July. While annual energy generation from the reference photovoltaic panel is 11854.82 Wh, annual energy generation from the photovoltaic panel with a thermoelectric cooler is 14285.74 Wh with the increase of 20.5%. In conclusion, it is said that using a thermoelectric cooler on a photovoltaic panel may increase its energy generation and performance monthly with the average of 19.6%.