Patent Publication Number: US-2021175844-A1

Title: Waterless System for Cleaning Solar Panels

Description:
FIELD OF INVENTION 
     The present invention relates to waterless system for cleaning solar cells. More specifically, the present invention relates to a pneumatic cleaning system employed for cleaning solar cells. 
     BACKGROUND 
     Growing interest in renewable energy has led the solar photovoltaic industry to expand notably in the last decade. However, a big issue that is often overlooked is keeping panels clean. The output of a solar panel is mainly affected by different environmental factors like dust, color, irradiance, shading, etc. Also, accumulation of waste like bird poop on the panels results in reduced efficiency of the solar panel. 
     In order to overcome the said problem, various systems have been devised. Liquid based systems are one of the popular cleaning systems which provide water dependent cleaning of the panels. Considering water shortage all around the globe, utilization of water based systems is not a wise approach for cleaning panels. Also, autonomous cleaning robots have been introduced but such systems are only economical on a larger scale due to both installation costs and the fact that custom-made parts are needed to fit the plant. Moreover, these conventional cleaning systems are less efficient as dust particles tend to gradually accumulate on the PV surface making the cleaning task more difficult. 
     Therefore, a cleaning system which overcomes the hurdles of existing/conventional systems and offers an efficient, sustainable and cost effective solution to the aforesaid problem needs to be devised. 
     SUMMARY 
     A waterless system for cleaning solar panels is disclosed. The waterless system includes one or more solar panels with a nano coating. The system includes at least one compressor. The compressor pressurizes air at a predefined pressure. An air tank is coupled to the at least one compressor for storing pressurized air. The system includes at least one shut-off valve coupled to the air tank for regulating the flow of the pressurized air. The system includes a microprocessor for directing the opening and closing of the compressor and the shut-off valve. A frame is mounted on top of the one or solar panels for facilitating air flow and coupled to the shut-off valve. At least one work station includes a nozzle assembly for release of the pressurized air for cleaning purposes. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The following summary/description of illustrative embodiments, is better understood when read in conjunction with the appended drawings. For the purpose of illustrating the present disclosure, exemplary constructions of the disclosure are shown in the drawings. However, the disclosure is not limited to specific methods and instrumentalities disclosed herein. Moreover, those in the art will understand that the drawings are not to scale. 
         FIG. 1  illustrates an exemplary architecture of a waterless system in accordance with an embodiment of the present invention. 
         FIG. 2  illustrates an exemplary working of the waterless system  100  in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
     Prior to describing the invention in detail, definitions of certain words or phrases used throughout this patent document will be defined: the terms “include” and “comprise”, as well as derivatives thereof, mean inclusion without limitation; the term “or” is inclusive, meaning and/or; the phrases “coupled with” and “associated therewith”, as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, or the like; Definitions of certain words and phrases are provided throughout this patent document, and those of ordinary skill in the art will understand that such definitions apply in many, if not most, instances to prior as well as future uses of such defined words and phrases. 
     Wherever possible, same reference numbers will be used throughout the drawings to refer to same or like parts. Moreover, references to various elements described herein are made collectively or individually when there may be more than one element of the same type. However, such references are merely exemplary in nature. It may be noted that any reference to elements in the singular may also be construed to relate to the plural and vice-versa without limiting the scope of the disclosure to the exact number or type of such elements unless set forth explicitly in the appended claims. 
     Particular embodiments of the present disclosure are described herein below with reference to the accompanying drawings, however, it is to be understood that the disclosed embodiments are merely examples of the disclosure, which may be embodied in various forms. Well-known functions or constructions are not described in detail to avoid obscuring the present disclosure in unnecessary detail. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present disclosure in virtually any appropriately detailed structure. 
     The present invention discloses a waterless system for cleaning solar panels. The waterless system is a pneumatic cleaning system which employs pressurized air jet (pneumatic). Hence, use of water and associated water cost is eliminated. The present invention is an automated system and operated via a microprocessor. The microprocessor may be programmable logic controller. The waterless system causes reduction in the cost of manual operation. The waterless system cleans the solar panels in a way that all the dust, bird poop and all kinds of dirt are wiped out. From the aforesaid, the waterless system is a greener, more efficient and cost effective approach in cleaning the solar panels as compared to the conventional systems. 
     The waterless system is a portable assembly which includes one or more components. The components of the waterless system may be assembled/dissembled upon use. As shown in  FIG. 1 , the waterless system  100  includes a frame  101 . The frame  101  may be installed at the top edges of a solar panel. In an embodiment, the frame  101  is inclined at an angle with respect to a horizontal base, say ground at the top of the solar panel. The angle may correspond to the angle of inclination of the solar panel with respect to the horizontal base. The dimensions of the frame  101  may be dependent upon the size of solar panel for which it is employed. The height of the frame  101  may be such that it creates minimum shadow on the corresponding solar panel. 
     The frame  101  of the waterless system  100  may include a plurality of pipes  101   a  and a plurality of attachments. The pipes  101   a  may be constructed of any strong, durable and inert material. The pipes  101   a  may include without limitation, flexible hoses, chlorinated polyvinyl chloride pipes, aluminum pipes, etc. The pipes  101   a  may in turn be connected via connectors  101   b . Each connector  101   b  and pipe  101   a  may mate with each other via a plurality of threads. However, any other means to connect two pipes  101   a  may also be employed. The pipes  101   a  may include a provision to prevent leakage. For example, the pipes  101   a  may be coated or covered with armour. 
     The attachments of the waterless system  100  may include without limitation, one or more of a compressor  103 , an aftercooler  105 , a moisture collector  107 , an air tank  109 , a shut-off valve  111 , at least one drain  113 , at least one work station  115 , and at least one drain trap  117 . 
     The compressor  103  may be any kind of air compressor known in the art such as a reciprocating compressor, a rotary screw compressor, a rotary vane compressor, a rolling piston, a scroll compressor, a diaphragm compressor, an air bubble compressor or may even be a direct drive compressor. The compressor  103  may be connected to an air source at one end. The compressor  103  compresses the air from the air source to a predefined pressure to yield compressed air (or pressurized air). The pressure applied in the compressor  103  may range between 30 to 240 psi. 
     The compressor  103  may release the compressed air based upon environmental conditions. In an embodiment, the waterless system  100  includes one or more sensors which sense the environmental conditions. 
     The compressor  103  may be sequentially followed by the aftercooler  105  and the moisture collector  107 . The aftercooler  105  may be any type of heat exchanger known in the art which functions to cool the discharge from the compressor  103 . The aftercooler  105  reduces the amount of water vapour present in the compressed air by condensing the water vapour into liquid form. 
     The moisture collector  107  removes moisture from the waterless system  100  which is generated by the aftercooler  105 . The moisture collector  107  may be any type of moisture collector known in the art and may utilize without limitation, silica gel, calcium chloride, etc. to absorb moisture. 
     The air tank  109  is placed next to the moisture collector  107 . The air tank  109  is also coupled to the compressor  109 . The air tank  109  serves as a reservoir to store the compressed air obtained from the compressor  103 . The size of the air tank  109  may be large enough to accommodate the compressed air discharged from the compressor  103 . Also large surface area of the air tank  109  helps in dissipating heat from the compressed air. 
     The air tank  109  is a concealed chamber with an input line  109   a  and an output line  109   b . As shown in  FIG. 1 , the input line  109   a  is connected to the compressor  103  while the output line  109   b  provides a channel to discharge the compressed air further to the subsequent components of the waterless system  100 . The air tank  109  may include a discharge valve  109   c  placed at its bottom. The discharge valve  109   c  functions to empty the air tank  109  in case of any leakage repair, etc. Moreover, it may also be utilized to drain out the presence of any trace of water. Optionally/additionally, the air tank  109  may include a pressure indicator which displays the pressure of the compressed air. 
     The storage of compressed air in air tank  109  helps to control the pulsating flow of the compressed air from the compressor  103 . It also helps the compressed air to further cool and condense the moisture present thereof. The pressure in the air tank  109  is held higher than the system operating pressure to compensate pressure loss in the pipes. 
     A shut-off valve  111  may be disposed at a predetermined distance from the air tank  109 . The shut-off valve  111  may be coupled to the air tank  109 . The shut-off valve  111  functions to regulate and monitor the direction flow of compressed air. The shut-off valve  111  is a programmable device (in conjunction with a microprocessor). The shut-off valve  111  may be in open or close state depending upon the requirement. In an embodiment, a solenoid valve is used for the same purpose. 
     The waterless system  100  may include a drain  113 . The drain  113  may be a manual or an automatic drain. Preferably, in order to automate the waterless system  100 , automatic drains, for example, float operated drains, electronic sensor drains and electronic timer drains may be employed. The drain  113  acts as a receiver to hold the condensate of the compressed air. 
     The work station  115  is the main component of the waterless system  100  which performs cleaning of the solar panel. Each solar panel may have a single work station  115  or optionally multiple work stations  115  may be employed for cleaning the solar panel. The number of work stations  115  may depend upon the size of the solar panel system. The work stations  115  may be disposed on the frame  101  along the length on either side as shown in  FIG. 1 . The work stations  115  may be placed at a height lower than the frame  101 . For this arrangement, the work stations  115  may be supported on the frame  101  with the help of additional pipes which help in mounting the work stations  115  at a lower level. The work station  115  may include, without limitation, one or more of a shut-off valve  115   a , an air filter  111   b , a pressure regulator  111   c , a lubricator reservoir  111   d  and a nozzle assembly  111   e.    
     The shut-off valve  115   a  may be structurally similar to the shut-off valve  111  and is employed for the similar purpose. The air filter  115   b  is placed next to the shut-off valve  115   a . The air filter  115   b  is a device which may be composed of one or more fibrous materials. The fibrous materials in turn remove contaminants like solid particulates such as dust, pollen, mould, and bacteria from the air. The air filter  115   b  may additionally/optionally include a catalyst or an absorbent to enhance the filtering efficiency of the air filter  115   b . Therefore, the air filter  115   b  filters the compressed air to result in contaminant free compressed air which is subsequently dispensed. 
     The lubricator reservoir  115   d  may be placed next to the pressure regulator  115   c . The lubricator reservoir  115   d  stores a lubricator for lubricating the components of the waterless system  100 . Any lubricator which provides the following advantages: excellent rust and corrosion protection, high oxidation stability to maintain its viscosity and provide long service life, non-foaming, demulsibility properties to shed water and filterability without the worry of lubricant additive depletion, may be used in the waterless system  100 . 
     The nozzle assembly  115   e  may be detachably connected to the work station  115 . The nozzle assembly  115   e  may have predefined dimensions. The nozzle assembly  115   e  may be flexible assembly which may be angled at a particular inclination for providing more ease in cleaning of the solar panel. 
     The nozzle assembly  115   e  may include a tube  115   f  and a nozzle  115   g . The nozzle  115   g  may be a pipe or tube of varying cross sectional area. The nozzle  115   g  may be used to direct or modify the flow of air. The nozzle  115   g  may also control the rate of flow, speed, direction, mass, shape, and/or the pressure of the compressed air that emerges from them. The nozzle  115   g  increases the velocity of compressed air at the expense of its pressure energy. The nozzle  115   g  of the waterless system  100  is a wide angled nozzle and delivers a compressed air jet to clean the solar panel. 
     The drain trap  117  may be placed along the width of the frame  101 . The drain trap  117  functions in removing liquid continuously and automatically without wasting air or gas. 
     In an embodiment, the components of waterless system  100  as disclosed above may vary based upon different environmental conditions and customized for different sizes of solar plants. For example, the waterless system  100  may include increased number of nozzle assemblies  115   e  for geographical locations prone to dusty weather such as desserts and/or when the size of solar plant is more. 
     The waterless system  100  as elaborated above may be mounted over a solar panel system. In order to enhance the cleaning efficiency of the waterless system  100  furthermore, the corresponding solar panel(s) may be coated with a coating/solution. The coating may be performed over a top surface of a solar panel. The solution may be a nano solution which may be for example, based on silicon by Si—O—Si bond. In an embodiment, the coating is a glass nano coating. The solution may be such that the glass surface of solar panel is rendered non sticky and slippery. The solution may have a flash point near 16° C. and self-igniting at approximately 200° C. 
     Nano coatings may be applied safely since they are chemically inert, tasteless, and colorless and have mild aroma. Further, nano coatings are stable in various environmental conditions and resist as well as protect surfaces against dirt, scratches and impacts. Nano coatings impart a glossy finish having a wet appearance with excellent durability to the surface. Several coating layers may be applied over the glass surface to result in better coverage. 
       FIG. 2  represents the working of the waterless system  100 . The waterless system  100  is an automated system with the microprocessor which controls synchronized operation of all the components of waterless system  100 . It must be noted that  FIG. 2  represents an exemplary working which substantiates the activation of a single work station. However, the waterless system  100  is additionally equipped to selectively activate few or all work stations out of multiple work stations at a time. 
     The waterless system  100  is switched on and subsequently, the compressor  103  starts to charge the air at step  201 . At step  203 , once the air is charged and reaches a predefined pressure, the compressor  103  stops automatically. 
     The microprocessor may determine the predefined pressure based upon the environmental conditions as sensed by the one or more sensors. The waterless system  100  may additionally include a pressure sensor which senses the pressure of compressed air at regular intervals, for example in every 2 minutes and transmits the same to the microprocessor. As soon as the pressure of the compressed air reaches the predefined pressure, the microprocessor signals the compressor  103  to stop. 
     The compressed air having predefined pressure is then stored in the air tank  109  after passing through the aftercooler  105  and moisture collector  107  at step  205 . It is important to note that the pressure of the compressed air is maintained at the predefined pressure while its storage. 
     At step  207 , the microprocessor activates the shut-off valves  111  and  115   a  to start the cleaning operation. The compressed air from the air tank  109  then flows through the frame  101  and subsequently flows through the work station  115 . 
     A timer is actuated to auto start the cleaning operation for an optimum time. The timer may be set for a predetermined period of time and at regular intervals throughout the day (or a timer value). The timer value may be selected by the microprocessor. The microprocessor may refer to the look up tables for selecting the timer value dependent upon the environmental conditions. 
     At step  209 , the compressed air is dispensed via the wide angle nozzle  115   g  to the corresponding solar panel. 
     The foregoing description of preferred embodiments of the present disclosure provides illustration and description, but is not intended to be exhaustive or to limit the disclosure to the precise form disclosed. Modifications and variations are possible in light of the above teachings or may be acquired from practice of the disclosure. 
     No element, act, or instruction used in the description of the present disclosure should be construed as critical or essential to the invention unless explicitly described as such. Also, as used herein, the article “a” is intended to include one or more items. Where only one item is intended, the term “one” or similar language is used.