Mech Wash

Overview

There are various ways to clean a solar panel which help maximize the efficiency output produced by the solar panel.  Certain cleaning methods are conventional which include using a hose or rainwater to clean the surface of a solar panel.  Other cleaning methods use an expensive device such as a drone or a robot for the same cleaning purpose.  Team 15 is determined to provide a practical cleaning device that can extend the efficiency of a solar panel.  Unlike conventional cleaning methods, Team 15 will engineer a device that does not use water or chemicals on the surface of the solar panel.  The device will be an inexpensive, semi-autonomous brush that will swipe across the solar panel to clear any dust and debris that will interfere with the solar panel’s efficiency.  This device will provide solar panel makers and customers an alternative to clean their solar panels.

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Phase I – Design Inputs

The purpose of phase 1 is to outline the specifications that are required for the project, develop various concepts, and select a concept based off of the product requirement specifications (PRS). The team distributed a survey to current solar panel owners in order to determine what was most important to solar panel owners when it came to cleaning their solar panel. The majority of solar panel owners wanted the cleaning device to be inexpensive and have low maintenance. The intended use of the cleaning device is for dry, arid climates, such as Nevada.

Some potential hazards were anticipated for the project, and various PRS items were used to eliminate injury to the device or user. For example, one PRS item is to cover the circuits from moisture and inclement weather as shown in Fig. 1. Most automated solar panel cleaners are $1000 or more depending on how many arrays need to be cleaned. In order to combat this, the team set a limit on the cost of the device at $600, listed in the PRS.

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Fig. 1: Product requirement specifications that outlines the design inputs of the project.

The Solar Panel Cleaner concept was chosen from three different designs: Wiper Blade, Belt Brush System, and Translating Brush. As shown in Fig. 2, the Wiper Blade and Belt Brush System designs either did not satisfy the PRS or was too complicated to complete within the time allotted.

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Fig. 2: On the left, the Wiper Blade design did not satisfy the PRS requirement of not using water. On the right, the Belt Brush System design had too many moving parts which made the design more complicated in comparison to the Translating Brush design.

The design that was chosen was the Translating Brush design, shown in Fig. 3, because it was a simple design with only one degree of freedom and satisfied the PRS.

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Fig. 3: Translating Brush design includes a brush the same length of the panel to translate from one edge of the panel to the other by means of a track on the top and bottom of the panel.

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Phase 2 – Design Outputs

Phase 2 shows how the project design will meet the design inputs. A top level drawing of the device is shown in Fig. 4 which demonstrates all the components that were incorporated into the project.The drawing shows two separate components of the project which includes: solar panel stand, and Solar Panel Cleaning device. The cleaning device is the main focus of the project. The device was designed to be attached to the solar panel stand preventing any modification to the solar panel module.

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Fig. 4: Top level drawing of the Solar Panel Cleaner device.

The main components of the device were separated into five different sub assembly models. As shown in Fig. 5, the new motor sub assembly are the components that make up how the motor is attached to the brush, as well as how the motor is attached to the pinion. The set-screw coupler attaches the pinion axle to the motor axle.    

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Fig. 5: Sub assembly drawing of the New Motor Sub.

The brush connector is important, because it connects many of the parts together, including: the brush, linear bearing, and angled motor brush attachment. The screws that connect the brush to the brush connector are oriented in the center of the part, as shown in Fig. 6.

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Fig. 6: Part drawing of the Brush Connector.

The electrical schematic, shown in Fig. 7, displays how an Arduino was used to store the code of the device which allowed it to autonomously translate across the panel.  A motor and two ultrasonic sensors were connected to the Arduino to control the movement of the device.

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Fig. 7: Electrical schematic of the Arduino connections to the motor and ultrasonic sensors.


Phase 3 – Verification and Validation

Verification

There were several verifications made by using codes already in place that govern the engineering field.  These codes ensured the team was staying within general guidelines.

Validation

The before and after images show how we tested the device by using dirt as the debris for the device to clean.


Phase 4 – Fabrication

Fabrication was well underway, during March 2016, after the prototype was chosen. The machine most commonly used by the team was the CNC Mill in order to drill holes into parts to allows bolts to connect the two parts together, such as the geared rack and geared rack holder shown in Fig. 7.

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Fig. 7: Using the CNC Mill to precisely drill into the geared rack.

A hand drill was used for other parts that were not so important to have a precise fit, such as the connection between the geared rack holder and stand shown in Fig. 8.

 

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Fig. 8: Hand drilling into the stand and geared rack holder.

The team also press fitted the geared pinion to an axle to prevent slipping from the pinion and axle.


Final Prototype

 

Benefits

  • Autonomous
    • Lower labor costs
  • Inexpensive
  • Easy installation
  • No water or chemicals
  • Regain lost efficiency
  • Quiet during cleaning process

Limitations

  • Cannot detect obstacles
  • Low speed
  • Dry substances only
  • Only programmable by technical personnel

Future Possibilities

  • Improve motor
  • Aesthetics
  • Wifi/bluetooth control
  • Solar battery
  • Add safety features

Meet the Team

Pedro Alvarado – Speaker and team contact who wants to work on renewable energy, such as, geothermal and solar.

Qiyu An – In charge of arduino and circuits who wants to find a job in data processing & any type of communication recording to data transition.

Kelly Shaner – Writer, task manager, and Solidworks operator who wants to obtain an engineering job, and then go back to school to study more.

Beverly Ma – Mathematician, writer, and organizer who wants to continue BS-MS program for Master’s in Mechanical Engineering with emphasis in fluid structure interactions.

Travis Smith – In charge of quality assurance and mediator who wants to work on biotechnology, with emphasis on applied heat transfer and fluid mechanics principles.


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