“Building Integrated photovoltaics with cost effective cooling” Karantagli Eleni (Ms Environmental Science Dep. University of Patras) Tripanagnostopoulos Georgios (Material Science Dep. University of Patras) Innovation Week on RES

What is therefore, more obvious than to cool the modules in order to increase efficiency? Temperature of PV Efficiency of PV

Two technologies in one module

In addition, heat from PV modules is transmitted to the building, mainly during summer, the building temperature rises over the acceptable comfort level and more electrical energy is needed to cover the increased load of the air conditioning system to reject this undesirable heat out to the ambient and to cool the building.

Also, during the installation of PV on the roof there is an empty space, about 10 cm, which will take advantage of, for our purpose.

“Heat Removal Unit” (HRU)

Hybrid Photovoltaic/Thermal Solar Energy Systems PVT/WATER PVT/AIR

PV’s characteristics Conergy Q 50PI Maximum Power (P MPP ) 50W Tolerance of Power +/-5% Rated Voltage (V MPP ) 16.5V Rated Current (I MPP ) 3.05A Open Circuit Voltage(V oc ) 20.0V Open Circuit Current (I sc ) 3.47A Maximum System Voltage 600V (insol. 1000W/m 2 AM 1.5 CEL T. 25 o C) MODEL CONSTRUCTION

Thermocouples

Experimental instruments Equipment: I-V system Pyranometer Temperature sensor

Azimuth 30 o Connection to water net

Experimental Procedure Tpv-f(°C)Tpv-b(°C) 12: :1562,568,1 13:3763,568,5 13:4164,569,1 Ir(W/m2)Ta(°C) 937,0233,5 First Stage: 69,1 °C 64,5 °C

Experimental Procedure First Stage: V(V)I(A)P(W) 1,932,8685,5 3,212,8679,2 5,192,86614,9 7,32,8620,9 12,082,79233,7 13,422,64335,5 13,842,4533,9 14,42,2532,4 14,72,14631,5 152,03130,5 15,31,89329,0 15,61,7527,3 15,91,57625,1 16,21,4723,8 16,51,219,8 180,3215,8 18,250,1562,8 Ir(W/m2)Ta(°C) 937,0233,5 Tpv-f(°C)Tpv-b(°C) 12: :1562,568,1 13:3763,568,5 13:4164,569,1 P max =35,469 W/m 2

Experimental Procedure Ir(W/m2)Ta(°C)flow 898,6234,20,0119kg/s Second Stage: Tin(°C)Tout(°C)Tpv-f(°C)Tpv-b(°C) 14:0025,227,760,463,7 T PV-b max = 69,1 °C T PV-b min = 63,7 °C

Experimental Procedure Second Stage: Ir(W/m2)Ta(°C)flow 898,6234,20,0119kg/s Tin(°C)Tout(°C)Tpv-f(°C)Tpv-b(°C) 14:1325,826,861,36464 V(V)I(A)P(W) 2,0472,9256,0 3,222,9349,4 52,914,5 6,982,92520,4 12,12,84434,4 13,422,66635,778 13,82,59535,811 14,412,41334,8 14,72,29233,7 152,16932,5 15,32,0431,2 15,61,89529,6 15,91,75327,9 16,21,57825,6 16,51,3923,023,0 180,56510,2 18,540, P max =35,811 W/m 2

Experimental Procedure Ir(W/m2)Ta(°C)flow 867,934,90,0334kg/s Third Stage: Tin(°C)Tout(°C)Tpv-f(°C)Tpv-b(°C) 14:3523,524,124,158,060,0 14:4322,823,759,060,3 T PV-b max = 64,1 °C T PV-b low = 60,0 °C

Experimental Procedure Third Stage: V(V)I(A)P(W) 2,0442,9486,0 3,212,9479,5 5,12,94315,0 6,982,93920,5 12,12,86134,6 13,442,67235,912 13,82,59835,852 14,422,42634,983 14,72,33834,4 152,2333,5 15,32,08631,9 15,61,95630,5 15,91,80428,7 16,21,66126,9 16,51,50824,9 180,58910,6 18,540,1913,5 P max =35,912 W/m 2 Tin(°C)Tout(°C)Tpv-f(°C)Tpv-b(°C) 14:3523,524,124,158,060,0 14:4322,823,759,060,3 Ir(W/m2)Ta(°C)flow 867,934,90,0334kg/s

Experimental Procedure Tpv-f (°C) Tpv-b (°C) 14: :0057,763,2 15:0558,565,5 15:1061,366,4 15:1559,567 15:2059,167,5 15:2558,367,3 Ir(W/m2)Ta(°C) 937,0233,3 Forth Stage: 67,3 °C 58,3 °C

Experimental Procedure Ir(W/m2)Ta(°C)flow 898,6232,00,0119kg/s Fifth Stage: Tin(°C)Tout(°C)Tpv-f(°C)Tpv-b(°C) 15:3123,324,524,5-63,2 15:4323,324,456,161,5 T PV-b min = 61,5 °C

Conclusions We observed a considerably reduction of PV temperature, which resulted an electrical efficiency improvement from 11,1% (without water flow) to 12.2% (with water flow). The second observation was the higher flow rate resulted to better cooling effect and in shorter time. On the opposite the higher flow rate of water resulted to lower temperature rise of it.

Suggestments - Improvements Decrease the distance between HRU and PV’s back side Increase of HRU surface The water circulation pipes of HRU could be metallic instead of plastic, but we must consider the additions of the cost To adapt a real installation on building inclined roof the suggested system should be tested with natural air flow under PV module

Thank you for your attention! Karantagli Lena Tripanagnostopoulos Georgios