[PV Robot Front Line] Cleaner Robot by Sinfonia Technology
Washes panel surfaces using water, brush, wiper
Fig. 7: Cleaning route examples. The robot has the capability to automatically come down to the lowest point of the panels and wait for a refill if it runs out of water or power halfway. (source: Sinfonia Technology)
Sinfonia Technology Co Ltd unveiled the "solar panel cleaner robot Resola" prototype 1 in November 2013 (Fig. 1). The company is planning to release an upgraded mass-produced model as a new product in the fall of 2014 (Fig. 2). Robot cleaners make us visualize iRobot Corp's "Roomba," and the "Resola" is like a solar panel version of the Roomba. It recognizes the surrounding environment with its sensors and cleans solar panels, automatically tracking its route according to its own decision. While the Roomba vacuums dusts, the Resola wets and cleans panels with a brush and a wiper.
To be priced at about 1.2 million yen
Provided with a built-in Li-ion battery and a water tank (2.7L), the Resola can clean about 75m2 (45 panels) in 30 to 45 minutes with a full tank; the tank will run out of water in about the same length of time. The rechargeable battery runs the robot for about five hours per charge and can then be replaced with another one (Fig. 3). The body weighs 22 to 23kg when the tank is full, which can be carried by one person (Fig. 4).
It can be used on panels tilted at 5 to 20° and run across panels spaced up to 3cm lengthwise, 5cm widthwise and 1cm up or down from each other. The Resola is compatible with both single- and poly-crystalline silicon panels but incompatible with thin-film types such as CIS and amorphous silicon panels. Sinfonia Technology's suggested retail price is about ¥1.2 million (approx US$11,685).
I witnessed the prototype 1's demonstration on the test panels at Sinfonia Technology's Ise Plant. The Resola was placed facing upward on the lower left corner of an array (unit of connected panels) tilted at 20°, and switched on. In a few seconds, it started climbing up the 20° slope. It detected that it had reached the upper end of the panel, stopped and rotated right by 90°.
The cleaning process started from here. The Resola sprayed water forward, horizontally running on the upper edge of the panels from left to right (Fig. 5). It washed the wet panel surface with the nylon rotational brush attached under the body and pushed away the dirty water with the wiper. The water ran down the 20° tilted panel toward the bottom.
President suggests idea himself, commercializes cleaner
The Resola detected that it had reached the right end of the array, turned downward by 90° and stopped after moving down a little (Fig. 6). Rotating left by 90°, it started running and cleaning horizontally from right to left this time. By repeating these actions, the robot washed the panels in series from the upper side (Fig. 7). As the panels were sloping, the water containing the dirt and dust gradually ran down the panels and was eventually removed when the Resola, running along the lower edge of the panels, pushed the water off under the mounting systems (Fig. 8).
"We assumed a usage that a robot automatically cleans solar panels while a mega (large-scale) solar power plant is being inspected," said Mitsuo Tsume, manager of the New Business Planning Div, Sinfonia Technology. As far as I saw, in the prototype 1's demonstration, this concept was already achieved. Product Development Manager Nakamura said, "It was exceptional that we could shape the idea into a product in just six months."
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