COOLBACK ENABLES PV MODULES TO YIELD MORE OUTPUT
It is a proven fact that a cooler PV module produces more output. The patented COOLBACK® technology stimulates natural convection and radiation to reduce a module’s operational temperature. Effective temperature management significantly reduces power losses from heat in PV cells, allowing cells to produce more energy.
COOLBACK® has the added benefit of preventing dust & dirt buildup, another factor that affects module temperature and reduces output. Traditional frame/backsheet modules have a rim that captures airborne particles. This is especially true in arid environments. COOLBACK’s frameless structure is engineered without a rim to tackle this issue.
The nominal cell output of a PV module is stated in manufacturers’ fact sheets at Standard Test Conditions (STC). These conditions are at cell temperature of 25oC and 1.000 Watts/m2 irradiation with Air Mass Number 1,5.
The nominal operating cell temperatures (NOCT) however are substantially above 25oC. At NOCT test settings (800 Watts/m2, air temperature 25oC, windspeed of 1 m/s) the cell is around 45oC.
PV cells produce less energy at high temperatures. Every degree above STC (25oC) delivers a decline of 0,4 – 0,5% of Power (this number is the temperature coefficient of the cells). If a PV module produces 300 Watts under STC, it delivers at 45oC degrees (45oC – 25oC = 20oC degrees hotter) an output of 20oC * 0,5% = 10% less. The 300 Watts are lowered to 270 Watts. The heat loss, in this case, is 30Wp of the nominal output. This 10% is the average heat loss PV Modules face in general.
Ambient air temperatures can exceed 25oC, and horizontal irradiation can surpass 800 Watts/m2. Air measuring 40oC with irradiation above 1.000 Watts/m2 is not exceptional, especially not in the more interesting solar harvesting locations. We know module temperatures reach 70oC – 90oC easily in these cases, resulting in heat losses of more than 30%.
A module’s lower operational temperature directly contributes to extra output. In fact, it decreases the heat losses significantly. The patented COOLBACK® technology achieves this by combining a backsheet that contains aluminum with aluminum gutter-shaped cooling elements that extend the surface on the reverse side of a module.
COOLBACK® increases a module’s surface area by 5 times. The larger surface area is designed with ventilation profiles and louvers to stimulate convection and radiation, which cools a module’s operational temperature.