In June 2021, WIND my ROOF tested the latest version of the WindBox® in the wind tunnel of the scientific and technical center for the building industry (CSTB in French) in Nantes. The objective was to validate the prototype, in order to start the industrialization and the first installations in 2022.
WIND TUNNEL TESTS IN PREPARATION FOR INDUSTRIALIZATION
The operation of the WindBox had already been validated in November 2019 during previous tests, in the same CSTB wind tunnel in Nantes. The fourth version had since been optimized, with a new geometry favoring aerodynamics. An effort to rationalize the number of parts and assembly time had also been made, with a view to deploying the modules.
The wind tunnel trials, supervised by Hervé Brebion and Jean-Paul Bouchet on the CSTB side, and by Yanis Maacha on the WIND my ROOF side, consisted of three tests.
Test 1: module performance
Heat vein
The objective of the first two days was to evaluate the power output of the wind turbine as a function of wind speeds. The WindBox was placed in the center of the vein and exposed to winds from 4 m/s to 20 m/s (14,4 km/h to 72 km/h). These tests allowed to qualify the energy performances of the wind turbine, validating the power curve shown on the right.
Test 1: module performance
Heat vein
The objective of the first two days was to evaluate the power output of the wind turbine as a function of wind speeds. The WindBox was placed in the center of the vein and exposed to winds from 4 m/s to 20 m/s (14,4 km/h to 72 km/h). These tests allowed to qualify the energy performances of the wind turbine, validating the power curve shown on the right.
Test 2: performance and snow resistance
Heat vein
Performance tests were then carried out under extreme climatic conditions, with temperatures ranging from -5°C to -15°C and with snow generation.
The results make it possible to quantify the power loss caused by snow. For example, when the rotor blades are covered with 3 cm of snow, a power loss of 30% is recorded for winds of 8 m/s (28.8 km/h). Temperatures, however, do not cause any problems for the turbine operation and do not damage the overall system.
Test 2: performance and snow resistance
Heat vein
Performance tests were then carried out under extreme climatic conditions, with temperatures ranging from -5°C to -15°C and with snow generation.
The results make it possible to quantify the power loss caused by snow. For example, when the rotor blades are covered with 3 cm of snow, a power loss of 30% is recorded for winds of 8 m/s (28.8 km/h). Temperatures, however, do not cause any problems for the turbine operation and do not damage the overall system.
Test 3: extreme wind resistance
Aerodynamic vein
The last test aimed to qualify the resistance of the wind module in case of strong winds and storms, in order to prevent any risk of tearing and breaking. The resistance was tested along two axes, the first with a frontal wind (0°), the second with a lateral wind (90°). The safety flap was raised to 20 m/s (72 km/h) to stop the electricity production and to secure the WindBox.
In both cases, the target wind speed of 50 m/s (180 km/h) was reached.
The wind tunnel tests and the impact of these high winds on the WindBox have highlighted two areas of improvement before the series production:
- The rear grill attachment system and a rotor blade came loose from their supports at 46 m/s (165 km/h), due to the loosening of the bolts holding them in place. On the production version, rivets replace the bolts for optimal resistance.
- The fixing feet, welded on a roof waterproofing model have plasticized (irreversible deformation). On future installations, a ballast system will reduce the stresses due to extreme winds.
Test 3: extreme wind resistance
Aerodynamic vein
The last test aimed to qualify the resistance of the wind module in case of strong winds and storms, in order to prevent any risk of tearing and breaking. The resistance was tested along two axes, the first with a frontal wind (0°), the second with a lateral wind (90°). The safety flap was raised to 20 m/s (72 km/h) to stop the electricity production and to secure the WindBox.
In both cases, the target wind speed of 50 m/s (180 km/h) was reached.
The wind tunnel tests and the impact of these high winds on the WindBox have highlighted two areas of improvement before the series production:
- The rear grill attachment system and a rotor blade came loose from their supports at 46 m/s (165 km/h), due to the loosening of the bolts holding them in place. On the production version, rivets replace the bolts for optimal resistance.
- The fixing feet, welded on a roof waterproofing model have plasticized (irreversible deformation). On future installations, a ballast system will reduce the stresses due to extreme winds.
LET THE INDUSTRIALIZATION BEGIN!
These wind tunnel tests validated the performance of the WindBoxes and qualified their resistance under extreme weather conditions. With the prototype series validated, WIND my ROOF began deploying a machined version with the help of SEGULA Technologies, through its subsidiary SIMRA. The teams have worked together to deliver the first eight modules in May 2022!
For more information on this partnership, click here!
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