About Us

Skilancer Solar is the brainchild of IIT Jodhpur alumni Neeraj Kumar with 3 years of work experience in the solar industry and Manish Kumar Das, an instrumentation engineer with 10 years of experience. The company specialises in providing permanent professional cleaning services [MCS] of solar panels of commercial parks and establishments. Some of our clients include Hindustan Petroleum, Adani, Ambit Energy and Unilink Group.

The solar module in order to produce power requires direct irradiance (meaning that this light is directly coming from the sun).However, other than internal factors (such as refractive index of glass, refractive index of EVA, composition of glass, etc.) there are various external factors as well which affect the amount of irradiance entering the solar module. One such factor is soiling and the loss of power associated with such factor is known as soiling loss. Soiling refers to accumulation of soil, dust particles, etc. on the solar module. This soil accumulation hampers the solar irradiance to pass into the solar module. This primarily leads to reduction of power output from the solar module. This reduced power output may remain till the module is cleaned which may not be soon enough. The result of soiling is that it leads to loss of money if not tackled properly. The effect on plant owner would be they would lose money due to reduced energy generation. Hence it is important to understand the factors effecting soiling, the factors that necessitate cleaning cycle.

The factors affecting soiling and the power loss are as follows:

Climatic conditions:  

The local climatic condition in conjunction with the geographical location of the solar power plant can have significant effect on soiling. The local conditions may be extremely dry/humid or a combination of extreme dry and humid weather (in few cases). This in addition with the continuous flowing wind would deliver soil and dust particles on the solar module.

Tilt angle of modules:  

The tilt angle of modules is known to affect the production of a PV power plant. It is known that the optimum tilt angle is the latitude of a particular location. However due to increased shadow length at such higher angles and/or space constraints, the tilt angle is usually kept at lower angles. However, it is a lesser known fact that such lower tilt angles (as low as 5° in few cases) causes an increased deposition of dust. A factor of energy loss due to soiling (generally between 3 to 5%) is considered while designing the power plant. However, power loss as high as 10-12% may be observed and are reported due to decrease of such tilt angle

Type of liquid used for cleaning:  

This factor can be directly attributed to the chemical composition of the liquid and its direct effect on the glass surface. Few droplets of the cleaning liquid always tend to stick to the solar glass when the module is cleaned. This liquid while evaporates may leave behind few of its deposits which usually vary in thickness. This would result in decrease in transmittance from the glass (as shown in figure below) which directly leads to loss of power output from module. Additionally, the varying chemical composition primarily reacts with the glass surface (and its ARC) which may either causes the dust to stick and settle on the glass

While the above mentioned parameters are important as they give information on how soiling loss occur and the factors which affect them. With soiling in place on the module, it is important to clean such modules to regain its power output. However there are few crucial factors which affect cleaning cycle. These factors are as follows:

Power gain vs frequency of cleaning: 

It is a known fact that cleaning of solar module is important. But it is necessary to understand what exactly should be the cycle time as cleaning cycle is usually associated with a cost. The outcome of the cleaning cycle is that the energy output of the cleaned array (and/or the power plant)increases which would lead to increase in revenue. However it is important to understand whether such increase in revenue would offset the cost of cleaning. Additionally it is also important to understand how often the cleaning cycle is required and would such regular cleaning offset its cost. The energy gain vs the no. of cleaning cycle is shown in Figure below, it is clear that there would be more than 25% of energy lost if no cleaning cycle is undertaken for a month. For one biweekly, one weekly and twice weekly cycle the energy output increases accordingly. For a country like Abu Dhabi where the local climatic conditions are dry and dusty, it makes sense to clean the solar panel once or twice in a week however for country like India, once in a week or two week cleaning cycle is fine.

Effect on module components (primarily Glass, EVA): 

While the above two points could be physically visualized and easily monitored, effect on module components cannot be seen. This is because once the dust starts settling over the glass, it would decorate the quality of glass. Additionally, with the dust longer settling on the glass, there are chances that it, along with moisture could seep-in to the module. This seep in addition to module power loss (in short term) leads to deterioration of module quality in long term and finally rendering the module useless. Such module (if not changed immediately) could have a significant effect on power output of the entire module array.

We can safely say that soiling has adequate impacts both at plant and module level. Thus it is important to keep the plant clean. However for number of cycles per week/month, one may keep it after a thorough evaluation of performance, cost and availability of resources. It is also suggested that the cleaning of power plants are carried out only by distilled water and/or suggested liquid by the module manufacturer/EPC provider. Additionally, we have seen many cases where performance of plant is gauged by its Performance Ratio (PR)(a ratio of how efficiently the plant is performing to the expected value). In few of those plants, we have seen that there is dust settlement on the irradiance meter (pyranometer) as well. Many a cases, these meter are located at such places where cleaning them may either be difficult or forgotten as it is unnoticeable. This decrease offsets the decrease of energy output of plant and the PR of the plants almost remains constant. Thus it is suggested that proper cleaning cycle is undertaken of such meters as well.The underestimation of soiling losses is due to a particularly stealthy effect. In most cases, the irradiance sensor suffers from the same amount of dirt that is covering the solar PV panels. Consequently, the measured irradiance level decreases, despite the actual irradiance remaining the same. The decrease in measured irradiance balances out the decrease in electricity generation of the panels, thus the PR does not change, effectively hiding the losses.

Fully‐automated cleaning devices are installed on each row of a PV system and are stored at a parking station at one side of each row. They are programmed to move along a single module row only. Most of the devices have an error detection system and take weather conditions in consideration before they operate.

All fully‐automated products operate with an on-board battery, although some devices may be additionally charged by their own PV modules. Fully automated devices may have an additional railsystem installed; obstructions between tables (space, steps and tilt) must be taken into account. As the name implies, fully automated devices do not require any manual labour for the cleaning process or for the positioning of the devices. Fully‐auto‐ mated devices can also operate during the night.

Design:  

The design of the device was a rolling brush that traverses along an array of solar panels. The device would attach to the array using rollers that grip the frame of the panels and use them as rails to roll along the panel. The system cleans the panel using a spinning brush to clear any dust or debris. Ideally, the device would not use water and would not need to be connected to any source of water.

Functional Analysis:  

We devised a system that moves along the length of an array of panels, cleaning the entire array. This design was selected primarily for its simplicity. Its component subsystems have been observed to function well in other applications. The device moves across a row of panels and cleans using a spinning array of brushes. The system will move using soft rubber wheels driven by an electric motor. The rotating brush system will be mounted on a rotating axle which is also spun by the main drive motor. Using a single motor is advantageous for both cost and simplicity. However, the drive motor will need to deliver high torque in order to function effectively. To reduce the stress on both the system and the panel surface, a series of lighter cleaning cycles will be used rather than a single more intense cleaning. This device will run across a row of panels and back to its original position. The device will be powered by an internal battery. At the end of each cleaning cycle, the system will return to a docking station at the end of the panel where it will recharge the battery. The dock system will act as an extended platform next to the panels to allow the system to move off the panel surface, so it does not obstruct sunlight from any part of the panel.The system uses a motorized brush to clean the surface of the panel array. The system is moved along the panel by two sets of motorized wheels, with one set located at either end of the device. The entire system is driven by a compact high-torque DC motor. The entire system is controlled by anonboard microcontroller which is paired with a dedicated motor controller. This control system is able to fully automate the system’s cleaning process with the ability to schedule cleanings at any given time.

Salient features of the robots:  

• Artificially Intelligent
• Safe & Reliable
• Internet Connected
• Energy Independent Operation
• No Water Required
• Autonomous
• Daily Cleaning of PV Modules