WO2019207599A1

WO2019207599A1 - An automated mechanism for cleaning solar power system

Info

Publication number: WO2019207599A1
Application number: PCT/IN2019/050328
Authority: WO
Inventors: Vinit PARADESHI; Ashwini CHAUDHARY; Niket DESHMUKH
Original assignee: HINGMIRE, Rashmi
Priority date: 2018-04-26
Filing date: 2019-04-24
Publication date: 2019-10-31
Also published as: AU2019260040A1

Abstract

An automated mechanism for cleaning a solar power system comprising solar energy generating modules such as solar panels, concentrating mirrors and the like that are utilized for generating power. A control mechanism operates in conjunction with a water storage system, water reclaiming unit and a fabricated boom structure with a pop up rotary impact sprinkler to periodically disperse water onto multiple of solar energy generation modules. Compressed hot air is dispensed by the sprinkler ensures the drying of the washed solar energy generating modules. The automated solar system cleaning mechanism capable of being compacted on portable trolley except the water reclaim unit. As a result of this automated cleaning mechanism, dust and debris are removed from the solar energy generating modules and prevented from further settling thereby allowing the solar energy generation modules to generate power at optimal efficiency.

Description

TILTE: AN AUTOMATED MECHANISM FOR CLEANING

SOLAR POWER SYSTEM

DESCRIPTION OF INVENTION

Field of Invention:

This invention relates to a cleaning of solar power system.

More particularly, the invention is related to an automated mechanism of cleaning the solar power system using a fixed system.

More particularly, the invention is related to an automated solar power system cleaning mechanism which is compacted on portable trolley.

Background of Invention:

Renewable energy system is playing vital role in the tackling the challenges posed by the global climate change. Majority of the countries in the world where there is abundance of sunlight, including India, are trying to convert maximum solar energy into usable form of energy. Photovoltaic (PV) solar energy is an efficient and renewable energy source. PV systems use crystalline silicon or thin film to convert sunlight into electricity without producing air pollution or hazardous wastes.

It has been stated by many luminaries in the world that the use of direct sun radiation on Solar panel(s) can potentially produce more than enough energy to meet world needs. The efficiency of the solar cells depends upon the ratio of the amount of light it receives to the amount of power it generates. The power output delivered from a solar photovoltaic (PV) module highly depends on the amount of irradiance, which reaches the solar cells. Many factors determine the ideal output or optimum yield in a photovoltaic module. However, the environment is one of the contributing parameters which directly affect the photovoltaic performance. Electrical characteristics of PV (Voltage and current) are varied with respect to shading due to soiling. Shading due to soiling is divided in two categories, namely, soft shading such as air pollution, and hard shading which occurs when a solid such as accumulated dust blocks the sunlight.

Soft shading affects the current of the PV module, but the voltage remains the same. For soft shading the voltage of the PV module will remain constant, and only the lower irradiance being absorbed by the solar cells leads to a decrease in current from the PV module.

In the case of hard shading, all of the cells of a PV module are shaded, and no power will be delivered by the PV module. Hard shading on some cells of a PV module will cause a decrease in voltage of the PV module, but because the unshaded cells still receive solar irradiance, the current will remain constant. The shaded cell acts as a resistance to current generated from the other cells. This causes the shaded cell to heat up and leads to a hot spot that can eventually damage the module.

Occurrence of dust storms and high concentration of airborne particles that may get accumulated on PV modules can further worsen PV performance. Soiling on PV modules can be a potential showstopper for the PV technology deployment. Such Dust storms are widely seen in desert-like areas across globe and more prominently in gulf region.

The solar facilities operation hardly gets appropriate attention to reduce the losses in a long time. There are vulnerable to, often overlooked, on-site omnipresent practicalities such as deposition of dust, bird droppings, sand, tree leaves and salted water-stains can significantly degrade the efficiency of solar installations. In recent research works and investigations revealed realize how significant performance loss caused by soiling of PV modules. Soiling accounts for dirt, snow, and other foreign matter on the surface of the PV module that prevents solar radiation from reaching the solar cells. The potential energy loss depends on the level of dirt and soiling solar panels have accumulated. Due to soiling loss average daily efficiency reduction of 0.2% in days without rainfall in dry weather & Annual losses caused by this trend due to soiling ranges from 1.5% to 6.2% depending on the location of the PV plant. It reduces output power from PV between 2% - 50 % in different areas. During one- month period power output may reduce from 87% to 75%. Dust accumulation reduce peak power around 18%.

In order to bring solar power a step closer to par with conventional sources of energy, efficiency rates or performance of solar system must improve. Big Solar energy projects or solar farms have huge number of solar panels installed and manual cleaning of each and every solar panel is a toiling task associated with massive costs.

Therefore, a specific configuration/mechanism has to be developed in order to harness maximum amount of energy from the solar system in a cost effective manner. Automated cleaning method prevents dust accumulation on the surface of solar arrays & improves performance of solar system.

The prior art reveals that there have been attempts to develop a manual or remote controlled solar panel cleaning system. In the existing state of the art, generally wet cleaning system uses a manual cleaning system with a hose, wiper, brush and water. Another wet cleaning system uses a manual cleaning with a jet spray or fix type sprinkler system. Following patent and non patent literature describes the existing state of the art.

Patent Publication No. W02016197013 - Solar Energy Collection Panel Cleaning System

The prior art describes an apparatus, method and system for cleaning a solar panel includes a solar panel, one or more fluid reservoirs, a fluid dispenser at a first side of a solar panel, a mechanism for providing pressurized fluid to the fluid dispenser from the fluid reservoir(s), and a mechanism for dispensing the fluid from the dispenser.

The invention applied for uses pop up rotary impact sprinklers for dispensing cleaning medium (water or air) which ensures uniform sprinkling of water on each module and impact action ensures proper cleaning of modules. The invention applied for also uses multi level reclaim water collector which ensures maximum recycling of water. The invention applied for uses fabricated boom structure which is used to hold sprinklers on solar array structure. The invention applied for uses of wireless control system & remote monitoring system for effective cleaning. The invention applied for has minimal operational cost as compared to the prior art of which the vibration system is bound to attract significant costs.

Patent Publication No. CN103084360A - Full Automatic Intelligent Cleaning Device of Photovoltaic Power Station Modules

The prior art describes a fully automatic intelligent cleaning device of photovoltaic power station modules, in particular to a high efficiency dust cleaning device for various long or short square photovoltaic modules of a large scale photovoltaic power station. The device described herein is in physical contact with the panels by a roller brush which may cause friction and face wear and tear of the surface of panels as well as the cleaning system and operation of which is controller remotely or manually. This prior art uses roller brush for both wet and dry cleaning.

The invention applied for uses a fully automatic system which is either fixed or mounted on a movable trolley. Additionally, the cleaning mechanism of the invention applied for does not damage the solar panel surface.

None of these related art references describe a method or a mechanism of enhancing the efficiency of solar power generation using an automated cleaning mechanism which is safe as well as cost effective. Accordingly, the present invention describes a method and a system of automatic cleaning of solar system.

Object of Invention:

The primary object of the invention is to provide a method and system of improving efficiency and performance of solar power system that overcomes many of the shortcoming of the prior art disclosed above;

Another object of the invention is to enhance performance of solar power system using automated cleaning mechanism;

Another object of the invention is to provide an automated cleaning mechanism for cleaning the solar power system wherein the solar power system is contact free from the cleaning mechanism and hence damage proof; Further object of the invention is to use the automated wet cleaning method for cleaning the solar power system;

Another object of the invention is to provide an automated solar power system cleaning mechanism which is fixed on to the solar power generating modules;

Another object of the invention is to provide an automated solar power system cleaning mechanism which is compacted on portable trolley;

Another object of the present invention to provide a new and improved method and system for cleaning the solar system wherein the technological disadvantages as outlined above including and related to the relatively large costs are reduced or substantially overcome.

Summary of Invention:

Accordingly present invention, An automated mechanism for cleaning solar power system describes a method and a system of automatic cleaning of solar system using wet cleaning method.

The automated system comprises a control mechanism, a power supply unit, a water reservoir, pumping unit, rotary impact sprinkler with a pop up spindle for dispensing water onto the solar array for cleaning, multiple sensors for controlling and feedback mechanism and water reclaim system.

The control mechanism is programmed to automatically clean the solar system. The cleaning period, intervals of the cleaning and days of cleaning are calculated based on controlling and feedback mechanism such as the data provided by weather station, dust sensor, LDR sensor output, image processing provided by CCTV and drone surveillance system. The cleaning mechanism can be fixed with the solar power generating system and the said mechanism can be compacted on a portable trolley as well. The cleaning mechanism is fixed in such way that the solar power system remains contact free from the cleaning mechanism ensuring damage proof system with optimal efficiency. Brief Description of Drawings

The accompanying drawings constitute a part of this specification, and illustrate one or more embodiments of the invention. Embodiments of the invention are described below with a working example and with reference to the accompanying drawings wherein:

Fig. 1 is the flow chart of automated mechanism for cleaning solar energy generating system/module constructed in accordance with the present invention;

Fig. 2 is the schematic diagram of the automated mechanism for cleaning solar energy generating system/modules. The depicted system describes a control mechanism connected with the system and the sensors via control cables (38);

Fig. 3 is the schematic diagram of the automated mechanism for cleaning solar energy generating system. The depicted system describes a control mechanism connected with the system and the sensors via wi-fi, transmitter and receiver, Bluetooth, GSM and LAN network (14);

Fig. 4 is the schematic diagram of the multilevel water reclaim unit (18) of the automated mechanism for cleaning solar energy generating system;

Fig. 5 is the diagram of the boom structure with perforated mounting unit (39), angle setting nut bolt (40), degree adjustment slot (41) and sprinkler holding clamp (42);

Fig. 6 is the perspective view of the boom structure fixed on portable van (55) with vertical mounting rod (43), vertical rod mounting clamp (44), horizontal mounting rod (45), tension spring (46), degree adjustment disk (47) and sprinkler holding rod (48);

Fig. 7 is the perspective view of a sprinkler unit (17) mounted on a pop up spindle (59). The rotary impact pop up sprinkler is a water lubricated drive with an arc setting ranging from 0° - 360° and radius of nozzle (60) trajectory ranging from 1 m - 16 m;

Fig. 8 is the diagram of the portable trolley carrying solar PV panel (5), pumping unit (10), pop up rotary impact sprinkler (17), inlet pipe (35), control cable (38) and boom structure (56); Fig. 9 is the diagrammatic representation of the portable trolley carrying the automated cleaning mechanism for cleaning solar energy generating system/modules.

Detailed Description of the Drawing:

The present invention relates generally to an automated mechanism for cleaning a solar energy generating system/modules.

In the context of the present application, solar energy generation system comprises solar energy generating modules (34) such as solar panels, concentrating mirrors and the like that are utilized for generating power. In accordance with varying embodiments, a control mechanism operates in conjunction with a water storage system (58) and a fabricated boom structure (56) with a pop up rotary impact sprinkler (17) to periodically disperse water onto multiple of solar energy generation modules. Subsequently, compressed hot air is dispensed by the sprinkler (17) ensuring the drying of the solar energy generating modules. As a result of this automated cleaning mechanism, dust and debris are removed from the solar energy generating modules and prevented from further settling thereby allowing the solar energy generation modules to generate power at optimal efficiency.

Various features of the embodiments disclosed herein can be used alone, or in varying combinations with each other and are not intended to be limited to the specific combination described herein.

In one embodiment constructed in accordance with the present invention, the automated solar system cleaning mechanism is a fixed system.

In another embodiment constructed in accordance with the present system, the automated solar system cleaning mechanism is compacted on portable trolley (55) except the water reclaim unit (18).

In one embodiment constructed in accordance with the present invention, the master controller (1) has control cables (38) to receive and send the commands to the system. In another embodiment, the master controller (1) is configured to be compatible with wireless communication mode such as Wi-Fi or bluetooth or LAN network (14). In another embodiment, the master controller (1) is configured to be compatible with existing SCADA system (28) for remote monitoring and control.

In another embodiment, the master controller (1) is configured to control the cleaning system via mobile application (29).

The programmable master controller (1) is connected to the power supply source (32) and a protection system panel (8).

Power supply (32) & protection system (8) provides power to automatic cleaning system. It consisted solar PV (Photo Voltaic) system or readily available nearest source of power. In case of solar PV system, solar inverter converts DC (Direct Current) power supplied by PV array to lph/3ph AC (Alternate Current) power to power up the automatic cleaning system.

Protection unit having inbuilt protections to automatic cleaning system against issues such as short circuit, over voltage, under voltage, sudden variations, leakage current, ground faults etc.

Power supply & protection system provide power to master controller (1), pumping unit (10), air compressor unit (9), water heating elements (3), auxiliary supply to solenoid valves (15), sensors, CCTV, Human Machine Interface- HMI (27), Monitoring unit (30).

The master controller (1) is programmed to automatically clean the solar system. The cleaning period, intervals of the cleaning and days of cleaning are calculated based on controlling and feedback mechanism such as the data provided by weather station (23), dust sensor, LDR (Light Depending Register) sensor output (19), image processing provided by CCTV (26) and drone surveillance system (25).

Master controller (1) receives signal from water level controller & based on input, Master controller sends command to inlet control solenoid valve (15) to fill water in reservoir (2) from RO water system (13). After filling up the reservoir (2), Master controller (1) receives the signal from water level controller (21) & master controller shuts down the inlet valve. Controller gives command to pumping system to start of cleaning cycles as per programmed instructions. After completion of cleaning cycle, controller gives command to air compressor unit (9) to start drying action. Compressed hot air ensures complete drying of modules.

Immersion type water heater coils are used in water reservoir for heating the water during winters to clear the ice on the solar panels. Temperature sensor provides data to controller for controlled heating of water.

The system uses pop up rotary impact sprinkler (17) for dispensing the water on to the solar modules. Sprinkler rotors are spaced depending upon the solar system size and array configuration.

Sprinkler heads also allows fine-tuning arc settings through the top of the sprinkler, without any complex disassembly required. Rotor Sprinkler features an adjustable 0° - 360° arc for versatile coverage. A Rain curtain (33) is formed while cleaning which ensures uniform and effective cleaning of the surface. The rotary sprinkler provides water-saving efficiency and uniform water distribution for consistent results. A durable rubber cover helps to prevent dirt from entering the rotor while a large water screen helps to minimize clogs. The water-lubricated gear drive delivers long-lasting performance. Sprinklers (17) provide the perfect simulation of rain & rain curtain of sprinklers ensure uniform water sprinkling on solar PV module. Angular degree adjustment (41) of rotor sprinkler allows to change the trajectory & direction of water flow which ensure uniform distribution of water on surface. Impact action of sprinkler ensures the proper cleaning of solar modules. Adjustable nozzle trajectory of sprinkler helps to cover maximum solar photovoltaic array.

Further embodiment of the invention has a fabricated boom structure (56) which is used to hold sprinklers on solar array (34) structure. Location of mounting depends on spray pattern to cover maximum solar array (34). Direction of flow & trajectory may be upward or downward depending on spray pattern & mounting arrangement.

The present invention has a multi level water recollection unit (18). Reclaim water flows through the spiral shape copper tubing mounted on back side of solar PV module. Reclaimed water can be recycled after filtration & pumped to main reservoir. Reclaim unit has following operation modes as per the requirement: During summer season, reclaimed water extracts waste heat from solar PV module & helps to reduce the cell temperature which enhances the PV cell efficiency. In particular, the filtered reclaimed water passes through heat exchanger (53). The heat exchanger extracts heat and yields hot water which can be used for various applications.

During winter season, particularly when it snows, the pre heated water flows through the reclaim water copper tubing which helps to melt the snow situated on solar PV modules.

Working example of Invention:

The automated cleaning mechanism for cleaning the solar power system is tested at megawatt (MW) scale solar power project. The controller is programmed to start the operation of automated mechanism daily at 8:00 pm for five minutes cycle on a system having one module mounting structure comprises of eighty solar PV modules.

Solar system performance is monitored by using SCADA (Supervisory Control and Data Acquisition) system. After installation of automatic cleaning mechanism, string performance data is fetched (cleaned by the present automated mechanism for cleaning solar power generating system/modules) from SCADA system & compared randomly with other strings data (which are not cleaned by the present mechanism of invention applied for). All strings are connected in parallel manner hence string voltage is fairly constant. String power is directly proportional to string current hence the strings current data was monitored randomly & prepared the resulting data bank for analysis.

Master controller (1) checks on the water level in the reservoir (2) and accordingly commands RO (Reverse Osmosis) purifier (13) to fill the water reservoir (2) if empty by switching on the Inlet control valve (15).

Depending upon the data feedback from the surveillance system, the programmed master controller (1) starts cleaning cycle by giving command to the pumping unit (10). The pumping unit (10) sends signal to sprinkler (17) to dispense water on the solar power system. Depending upon the availability of water and pressure thereof, either one or all of the sprinklers (17) can be switched on. If water availability and requisite pressure is low then one sprinkler dispenses water at a time for a defined time interval and thereafter second sprinkler is switched on after turning off the previous one thereby cleaning the solar array (34) maintaining optimal efficiency and with saving of water.

After water cleaning with water, air compressor unit (9) is switched on to dry the solar power system so that water droplets do not interfere in the functioning of the system.

The water used to clean the dust and debris on solar power system is reclaimed via a multilevel water reclaim unit (18).

The reclaimed water is passed through the filtering unit (11). Depending upon the weather and the season, the filtered water is passed further. During summer season or on hot and sunny days, the filtered water passes through the heat exchanger (53) which absorbs heat from the water, then cold water is passed into the reclaim pumping unit (12). The cold water then passes through the copper tubes fixed on the back side of the solar power system. The cold water cools the system and prevents any damage that might happen due to excess heating during summers. During winter season, the filtered water is allowed to pass through a water heating element (52). The Hot water is passed through the reclaim pumping unit (12) and then through Copper tubes it is passed so that the ice or snow accumulated on solar power system can melt.

It is observed that performance of solar power generating system/modules improves at least 4% and can even go up to 10%.

Following table demonstrates the increase in efficiency of the solar power generating system using the automated cleaning mechanism in the invention applied for.

Claims

Claims: We claim,

1. An automated system configured to clean the solar power system, the said system comprising:

a) A power supply unit (32);

b) A master controller (1);

c) A pumping unit (10) and piping system;

d) A sprinkler unit (17);

e) A boom structure (56);

f) A water reclaim unit (18);

g) An air compressor unit (9);

h) A surveillance sensor unit;

i) A wireless control system (14);

j) A remote monitoring and control system (30).

2. The system as claimed in Claim 1, wherein the master controller (1) monitors system performance and controls operations.

3. The system as claimed in Claim 1, wherein the sprinkler unit (17) is a rotary impact sprinkler with a pop up spindle (59).

4. The system as claimed in Claim 1, wherein the sprinkler unit is a water lubricated drive with an arc setting ranging from 0° - 360° and radius of nozzle (60) trajectory ranging from 1 m - 16 m which forms a rain curtain (33) during the cleaning process.

5. The system as claimed in Claim 1, wherein the boom structure (56) is a sprinkler unit (17) holding structure with perforated mounting structure (39) and has an angular degree adjustment slot (41) configured for rotation of 0° - 180° .

6. The system as claimed in Claim 1, wherein the water reclaim unit (18) comprises a reclaim water collector , filter, heat exchanger (53), heater (52), copper tubing, pumping unit (12), control valve and a controller (54). The system as claimed in Claim 1, wherein the surveillance system comprises CCTV (26), a drone surveillance (25) and a Light Dependent Resistor (LDR) sensor (19).

7. The system as claimed in Claim 1, wherein the wireless control system comprises wi-fi, transmitter and receiver, Bluetooth, GSM and LAN network (14).

8. The system as claimed in Claim 1, wherein the automated solar system cleaning mechanism is compacted on portable trolley (55) except the water reclaim unit (18).

9. A method of automatic cleaning of solar power system, the said method comprising:

i. Monitoring the solar power system using remote monitoring and control system (30);

ii. initiating cleaning cycle using the programmed master controller (1) which commands to the pumping unit (10);

iii. signaling the inlet control solenoid valve (15) to fill water in the reservoir (2) from Reverse Osmosis water system (13);

iv. shutting down the inlet valve (15) after filling up the water reservoir (2); v. signaling the pop up rotary sprinkler (17) to dispense water on the solar power system;

vi. formation of rain curtains on to the solar power system;

vii. commanding the multi level water recollection unit (18) to reclaim the used water and pass it through filter (11) and then through spiral shape copper tubes fixed on the back side of the solar power system;

viii. sending command to air compressor unit (9) to start drying action.

10. The method as claimed in Claim 10, wherein the filtered reclaimed water, during summer season, passes through the heat exchanger (53) which absorbs heat from the water and then cold water is passed into the reclaim pumping unit (12) to pass through the copper tubes which cool the solar power system resulting efficient performance.

11. The method as claimed in Claim 10, wherein the filtered reclaimed water, during winter season is passed through a water heating element (52) which heats up the water and then the Hot water is passed through the reclaim pumping unit (12) which then passes through Copper tubes in order to melt the snow accumulated on solar power system.