We have been experimenting with VFDs to run conventional AC Pumps using DC power of solar panels as in previous post (HP Size Solar Pumps) This is because there are a couple of good quality Solar MPPT VFDs easily available at fair prices.
However the VFD requires relatively high DC input voltage, 290 to 360VDC to run a single phase AC pump, and 440+VDC to run a three phase pump.
At sub-HP power levels the solar panels in commercially available sizes (250 to 330 Watt and 36 to 44 VDC each) are most often not going to add up to the input voltage requirements even for a VFD that will run a single phase AC pump.
To deal with this issue, there is a thought process that some kind of DC to DC boost converter can be used from low voltage DC source to raise the DC voltage in the acceptable range for to the VFD.
As a quick check a small experiment was carried out involving following components.
DC source from 8 x 60 W 36VDC array of panels but on a fully cloudy day. The open circuit voltage at the panel output was around 24 to 34 VDC.
A low cost inverter board that runs on SG3524 chip and MOSFETs, it produces approximately 50 Hz square wave AC output.
3. Salvaged transformer from a household inverter, 12-0-12V to 230V centre tapped, this is rated for around 700VA.
4. Frecon make solar VFD for single phase AC output.
The overall assembled setup is shown in the next picture.
To measure the output voltage and to view the wave pattern, a hobbyst’s oscilloscope (DSO138) was used. At the high voltage side output of the transformer a voltage divider comprising of 22kohm, 1.6kohm and 22kohm was connected. The measuring probes of the oscilloscope were connected across the central 1.6kohm resistor, thus the voltage measured on the oscilloscope is scaled down by a ratio of 1.6 : 44 (i.e. 1 : 27.5). Or in other words, the measured voltage on oscilloscope need to be multipled by 27.5 to get the actual voltage level at the transformer output.
When the DC power was applied to the inverter and VFD was connected to the transformer output, but not yet switched on, the output from transformer showed as in below picture. Oscilloscope showing 8V means the AC output was +220/-220 V peak to peak and 6.84 x 27.5 = 188 VAC RMS. The DC voltage at inverter input was seen to be in range of 12V.
In this case, the LED display of VFD showed a DC input voltage as 172 VDC. This is not really adequate for a single phase solar VFD, while it requires 290 to 360VDC input for normal operation.
When VFD was switched on, the output voltage from transformer was seen to be reduced. Oscilloscope showing 7.04V means the AC output was +193/-193 V peak to peak, and 2.21 x 27.5 = 61 VAC rms. The DC voltage at inverter input was at 6V. More importantly the waveform is highly distorted and is most likely due to not enough driving power for the transfomer of the inverter, suggestive of shortfall in power available from solar panels.
It would be fair to conclude that this conept as such is ok but the voltage levels and power efficiency need to be experimented further and evaluated.
Adequate power and volage from Solar panels need to be made available on a bright sunny day.
May be, high frequency switching with suitable ferrite or equivalent transformer need to be used.
Centrifugal pumps running on normal AC power supply are very common, fairly efficient and most importantly they are locally available from wide range of manufacturers. Their use and operation is more or less hasslefree, they are easily serviceable at nearby workshops and pricewise also they are affordable. These points are specifically important in comparison to a classical solar pump system that is available in market these days, and which potentially uses a BLDC 3 phase DC motor/pump with permanent magnets and all stainless steel body.
These standard AC pumps are available in 0.5 HP to 10s of HP of power rating, able to run on single phase (220V) or three phase (415V) AC power supply and available in formats like monoblock pumpset, openwell submersible and borewell submersible pumps.
This article discusses the use of such standard AC pumps using Solar Panels as the source of electricity.
Since solar panels generate DC voltage, it is important to have some mechanism or device to convert the DC electricity from the panels to AC power so that the pump can run on it.
A standard AC motor consumes large amounts of current during startup for a few seconds, this current can be 2 to 6 times of the normal operating current at full load. On the other hand solar panels are a current limited source of power i.e. the current output available from a given solar panel is limited by the size of panel. This means that the solar panels which would be sized and selected to meet the current requirements of the pump at normal operating load are not going to be able to start the pump in normal or traditional manner. Some kind of soft start approach is needed.
Also based on sunlight available over the day time, the output voltage, current and power from solar panels is going to vary, this needs to be maximized by making the pump run at various voltage and/or AC frequency. The standard AC motor which is expected to operate at 50 Hz power supply, can actually be made to run over a range of supply frequency (35 to 55 Hz) without any significant side effects. In this range of frequency, the output power of the motor varies almost linearly and this inherent feature can be used to match the solar panel output with the pump-motor power requirements.
All the above leads to a solution which has to be based on some sort of electronics to support following features.
DC to AC conversion
Soft start or gradually increasing voltage during startup
Output voltage and frequency modulation to optimize the power generation from the solar panels.
For 1 and 2 above there already exists a robust industrial device called Variable Frequency Drive (VFD). VFDs are often used in various industries to control the load and/or speed of standard AC motors which drive the heavy plant and machinery.
Most VFDs allow AC (single or three phase) or DC power supply as input and generate three phase AC power as output.
Internally the input AC power supply is first rectified to DC, that is what makes VFD suitable to run with Solar Panels. Then a microcontroller based circuitry drives a set of power transistors (IGBT or MOSFETs) to achieve DC to AC conversion with a SPWM (sinusoidal pulse width modulation) technique.
The output power is a sine wave with a configurable mains frequency (10 to 60 Hz as an example) but laden with spikes or chopped waveform with a carrier frequency of a few kilo-Hz. This is acceptable for standard AC motors, or rather the carrier frequency used in commercially available VFDs is optimized to keep the motors healthy and not to generate any ill-effects, especially high frequency harmonics.
The same waveform as explained and shown above, is generated in all the three phases of the output, but appropriately phase shifted by 120 degrees from each other. That makes a nice power source for a three phase AC motor.
During startup the VFD outputs a lower frequency of say 10 Hz and correspondingly lower pulse width (effectively a reduced AC voltage at the output). It is then gradually increased over a period of 5 to 15 seconds to normal operating frequency of 50 Hz. That is how a soft start is implemented.
VFDs have a simple and basic keypad with start, stop, menu buttons. Keypad permits setting of various configurable parameters, and also displays the operating status/errors if any.
Connectivity with external controlls is also provided, which allows dynamically setting the output frequency and voltage, external start and stop commands etc.
A fewer brands of VFDs have started manufacturing VFDs with additional features as below.
Customized phaseshift of 90/110 degrees (instead of 120) between the three output phases, to emulate the 3 wire power supply of a single phase capacitor run motor.
Changes to output frequency at runtime based on an inbuilt MPPT (maximum power point tracking) algorithm, essential for solar panels.
With the concept explained so far as above, we have carried out a few real life tests using a VFD and borewell submersible pump.
Equipment used is listed below
FRECON Make Solar VFD, model number FR150T – 2S – 2.2B -H, this accepts single phase AC input or DC input and gives out 3 phase 220 VAC. Has configuration settings to connect a single phase motor across the three U V W output terminals, and also has a MPPT algorithm in-built into it. It is not a Make In India brand but has ample presence of local dealer network in India. Build wise seems a good robust build.
Kirloskar make borewell submersible pump model Jalaraj KP4-1009 with 10 stages impeller, single phase 1 HP, 220VAC oil filled motor.
An unbranded borewell submersible pump, 10 stages, 0.5 HP 220VAC water filled motor, purchased from local market.
Energy Meter Secure Make, single phase 220VAC 30 Amps, 3200 pulses for 1 KWH unit consumption.
Power was taken from normal household AC supply
Water flow and pressure measurement was carried out using conventional simple techniques.
Normal AC power supply was connected to the input of VFD
Output terminals of the VFD were connected to the pump as given in the user guide of the VFD, i.e. U>>Y, V>>R, W>>B
Two different voltage settings were used for testing at 100% and 80% of normal using F00.16 configuration of VFD.
Valve in the delivery line was kept open in such a way as to be near the operating point to get 2.5 to 3.5 bar pressure and around 1800 LPH flow.
Below are few images and videos related to the tests carried out.
The VFD was tried in two different wiring arrangements. Two wire output mode: This is as per connection F08.00 = 1, whereby the run capacitor of the motor would be kept in circuit and only two wires of the VFD output were connected to the motor starter. In this case it was seen that the motor draws relatively more current untill it starts rotating and there after settles down to normal operating current. The starting current in this case is not as high as it would be otherwise on normal AC power supply, but still higher than running current. This is expected to be so and likely due to the inadequate capacitance at lower starting frequency. Three wire output mode: This is as per connection F08.00 = 2, as shown in figure 2.11 In this case the motor draws steadily and gradually increasing current until it stabilizes to the normal running current. This is a very important and useful aspect of the connection arrangement supported by this VFD since it will help deployment of optimum capacity of solar panels.
It is essential to carry out similar tests with input power taken from suitably selected solar panels at various time of the day.
An online calculator for panel capacity is presented here at the below link. This will be useful to select the panel ratings for a given pump capacity.
On 30-March-2022 this VFD and 1HP single phase pump was installed at a farm site in Murbad.
Total of 1600 Watt Solar Panels are used to drive the VFD which is a mixed set as below. 8 x 100 Watt 18 V in series with ( ( 4 x 100 Watt 46 V in series ) x 2 such strings in parallel )
It was seen that pump delivers 3000 to 3600 LPH water at about 30 feet total head, panel side voltage found to be in the order of 300 to 330 VDC, the VFD appropriately keeps regulating the output frequency from 35 to 50 Hz in order to maximize the solar energy generation from the panels and the VFD output voltage was seen to be in range of 160 to 220 VAC.
Long term trial run is planned and results will be published.
We see solar panels installed at various places but not in use due to various reasons like
Battery not existing or damaged / end of life
Devices powered from the panels no more existing or damaged beyond repairs.
Few from the set of panels are damaged / glass broken.
These panels are in various sizes starting from as small as 20 watt to 250 or 300 watt per panel and in numbers ranging from 1 to 8 or 12 at any one given site.
Such installations are a common sight in rural areas, in form of Grampanchayat Solar Street Lights, and at Z P Schools where a battery based solar electric system was previously installed. Such ZP school systems, as far as we have seen, are in range of 1 to 2 KW solar panels capacity and provided with fairly large size batteries.
Besides providing power in case of outage of electricity from MSEDCL, these solar systems were seemingly intended to supply daily electricity to the school and in turn reduce the consumption and to lead to lower or zero bill charges every month.
At the ZP schools where a battery based solar system has been installed, most often, after 2-3 years if not less, the useful life of the original supplied battery has expired and there are no arrangements to procure a new set of batteries.
In such cases the existing battery can not store the electricity generated by the panels and thus the school has to consume electricity from the grid through the energy meter provided by MSEDCL.
The connection provided to ZP schools by MSEDCL often is set to have a tariff category named LT Public Services Govt. Education. This tariff category has a monthly fixed charge (स्थिर आकार ) of 343 INR, which means that even if there is no energy consumption in a month, the school needs to pay this much amount towards electricity bill every month.
To summarize, such schools do have solar panels and dead batteries and on the other hand end up paying electricity bill every month.
Most schools need to pay bill from their funds whatever available or rely on Grampanchayat team to pay the bills. It is more often meticulous followup and related hassles of potentially untimely payments, sometimes leading to disconnection of electric supply to the school.
We propose that such sites are best suited for using the existing panels in a net metering arrangement with MSEDCL for the school.
We have carried out a survey to know what is the most important concern of the school teachers when it comes to electric supply, and below are the findings from schools in Murbad taluka of Thane district.
महावितरणकडून तांत्रिक कामांमुळे/दोषामुळे काही कालावधीसाठी वीजपुरवठा खंडीत होणे – ह्यापासून मुक्तता आवश्यक
वीजबिल भरण्याची अनियमितता, कटकट, खिशाला कात्री, निधीची कमतरता, बिल ना भरल्यामुळे वीजपुरवठा खंडीत केला जाण्याची भिती – ह्यापासून मुक्तता आवश्यक
As can be seen the majority of survey participants have expressed an opinion that reduction in the monthly electric bills is more important.
As a part of net metering arrangement, there is no need to install/maintain any batteries, electricity units generated from solar panels are used internally for school consumption and any excess are exported to electric grid.
The net metering approach involves following steps.
Permission for Solar Net Metering installation is to be formally obtained from MSEDCL for the consumer number of the school, through the online application form, application fees 590 INR need to be paid.
Existing solar panels are used to produce electricity.
If needed, the support structure for the panels may have to be reconstructed, approx cost 10000 INR.
DC electricity generated by panels is converted to AC power using a Solar Grid Tie Inverter, approx cost 23000 INR. The inverter is the only component that may need servicing in a very rare case, but comes with a 5 years warranty.
A Generation meter is installed which records the electricity units produced by the solar panels. Approx cost 1200 INR.
A Net meter is installed to measure the units Imported from and Exported to the MSEDCL grid, approx cost 2800 INR.
Net Meter is provided to MSEDCL for testing, fees 590 INR
Net Metering agreement as per standard content given by MSEDCL is prepared and printed on 200 INR stamp-paper to be handed over to MSEDCL.
MSEDCL, after site inspection, will hook up the net meter replacing the old meter.
Solar readings are then captured regularly by MSEDCL staff and billing as per the readings is initiated by MSEDCL as standard process.
As can be seen a total expenditure of about 45000 INR is necessary for a 2 KW system with existing panels to be put to use.
Near 0 amount of monthly power bill and no more fear of power disconnection for school.
Utilization of an important asset which otherwise would have simply been a waste/idle, namely the solar panels.
Green energy initiative put to practice.
All of this for about 20+ years, thus saving money for the Grampanchayat.
Starting in early 2021, and funded by Malati Vaidya Smruti Trust, a solar net metering installation has been successfully completed for consumer number 019000002570, Z.P. School, Milhe, Mhasa Dhasai Road, Murbad.
2 KW old panels were available from a not-in-use solar pump in custody of the Grampanchayat, who handed over the panels to school for the solar net metering project.
Just rececntly solar billing has started and school is seeing excess units exported to MSEDCL, these will be converted to monetary credit in the electricity bill for the school in month of March or April. Thereafter the credit amount will get utilized to pay off for the monthly fixed charges of subsequent months.
Request For Support
We seek contributors and donors to fund such projects and thus put to use the idling infrastructure (mainly the solar panels) and help the schools reduce their electric bills as much as possible.
For irrigation of small farms where water source is available nearby (either an open well, pond, lake or any such water body) it is possible to use small pumps and operate them on solar panels.
छोटे खेतों की सिंचाई के लिए जहां पानी का स्रोत पास में उपलब्ध है (या तो एक खुला कुआं, तालाब, झील या ऐसा कोई जल निकाय) छोटे पंपों का उपयोग करना और उन्हें सौर पैनलों पर संचालित करना संभव है।
These pumps are easily available at reasonable prices online as well as in local market in most of the cities and small towns accessible to farmers. They are used very commonly in battery operated backpack sprayers used for pesticides.
ये पंप अधिकांश शहरों और छोटे शहरों में ऑनलाइन और साथ ही स्थानीय बाजार में उचित मूल्य पर आसानी से उपलब्ध हैं। वे आमतौर पर कीटनाशकों के लिए उपयोग किए जाने वाले बैटरी चालित बैकपैक स्प्रेयर में उपयोग किए जाते हैं।
This post explains some important aspects of this type of pumps for use at small irrigation sites.
यह पोस्ट छोटे सिंचाई स्थलों पर उपयोग के लिए इस प्रकार के पंपों के कुछ महत्वपूर्ण पहलुओं की व्याख्या करता है।
Such a pump is run by a DC motor and has a PVC block head where positive displacement of water is achieved by action of miniaturized pistons inside the block.
ऐसा पंप डीसी मोटर द्वारा चलाया जाता है और इसमें पीवीसी ब्लॉक हेड होता है जहां ब्लॉक के अंदर छोटे पिस्टन की क्रिया द्वारा पानी का दबाव बढाया जाता है।
A pump having single motor is often priced at 550 to 650 INR and delivers upto 3 LPM water and claims to generate pressure of 70 PSI or 5 Bar i.e. upto 50 meters of height.
सिंगल मोटर वाले एक पंप की कीमत अक्सर 550 से 650 रुपये होती है और यह 3 लिटर प्रति मिनिट तक पानी दे सकता है और 70 पीएसआई या 5 बार यानी 50 मीटर ऊंचाई तक का दबाव उत्पन्न करने का दावा करता है।
Pump with twin motor is also available and priced at 1000 INR, delivers 5 to 6 LPM of water at similar pressure.
दो मोटर वाला पंप भी उपलब्ध है और इसकी कीमत लगभग 1000 रुपये है, समान दबाव पर 5 से 6 लीटर पानी की आपूर्ति करता है।
Next two images show a single motor and dual or twin motor pump.
अगली दो छवियां एकल मोटर और दोहरी या जुड़वां मोटर पंप दिखाती हैं।
The DC Motor used is a DC motor with brushes and follows a standard specification named as 775 motor, some details can be found here.
The motor can be operated over a wide range of DC supply voltage (6 to 36VDC) but the pump manufacturers normally mark the pump for operation in range of 12 to 14.5 VDC only.
We have installed such pumps at a couple of sites and safely connected to solar panels of 12VDC nominal (or 18VDC MPPT voltage). The motor of the pump nicely works with the electricity generated by solar panel during the daytime. As the intensity of sunlight changes throughout the day, the output flow of water varies and is acceptable for the irrigation purposes.
Inlet and outlet of the pump is however a non-standard (or at least not easily available) tubing size. Most suppliers provide a PVC/HDPE tube with threaded PVC nut to attach to the pump outlet nozzle, but the connectors with standard pipe sizes (say 0.5 or 1 inch nominal bore pipe) are difficult to find.
We have used a typical nozzle connection seen in pictures and created a simple skid mounted assembly of this type of pumps, eiether one pump on the skid or 2 on the skid as per the requirements.
With 2 pumps on the skid it is seen that 150 to 200 watt panels are adequate for operation throughout the day. For single pump a panel of 75 to 100 watt is appropriate.
Next few images explain the mounting approach we have used and is only a suggestion. Any suitable alternative can be followed that meets the needs and materials availability at the installation site.
Single Pump Skid
Dual Pump Skid
Front view of the pump skid with inlet and outlet pipes on left side.
Seen from top at an angle / 3-D view.
Left Side View
Right Side View
Pump and motor must never be submerged in water and water must not get into the motor.
DC power supply polarity needs to be correctly followed. Green wires to be connected to negative terminal of the battery or solar panels, and red wire to positive terminal.
DC supply voltage must never exceed 18 volts.
In no case, AC supply / mains supply shall be applied to the motor, it is hazardous besides the fact that it will permanently damage the motor.
Testing of pump without water by supplying DC power for a second or say two seconds is ok, but must not run the motor for longer duration without water.
At the inlet pipe a suitable filter in form of nylon mesh is highly recommended. The internal piston mechanism of the pump is too small to get clogged by smallest of the particles.
This type of pump can generally start from dry run and can self prime in a few seconds, but if it does not do so, please do not run it dry for long time. Instead open the nozzles and check if any clogging or blockages. Try to pull water from outlet nozzle or pipe by sucking the air.
The pump can lift water from upto 5-6 feet on the suction side, however it is better to keep the suction pipe length as small as possible.
It is recommended to install a footvalve at end of the suction pipe submerged inside the water, it is best to attach a filter mesh around the footvalve.
Make sure that the pump skid is mounted on a sturdy platform or base. Alternatively pump can be suspeneded firmly inside an openwell clearly above the water level.
Use solar panels of 12VDC nominal voltage only, any higher voltage panels if connected to the pump will damage the same. It is better to first check the nameplate on the backside of the solar panel before connecting for the first time. The nameplate should read 12VDC nominal and/or 17-18 VDC MPPT or maximum power voltage.
Single pump skid is suitable to operate with 75 to 100 Watt panel and dual pump skid with 150 to 200 Watts. Excessively higher wattage of the solar panels must be avoided.
This type of pump is supposed to be used for intermittent duty only however through our experimentation in actual sites, we find that using the pump every day for 3 to 5 hours is fine.
Connect the outlet pipe with suitable coupling or union with the delivery pipe to be arranged at the site to suit the distance of the final delivery location away from the water source.
Ensure that the inlet and outlet pipe connections do not lead to forces on the pipes or the skid.
If in doubt please reach out to us through email or phone.
Update on 21-Sep-2022
We have taken measurements of the pressure and flow generated from this type of mini pump and the videos below are useful to understand the performance.
It was seen that when operating with a 16VDC power adapter one twin pump could produce 2 Bar pressure (20 mtr water column equivalent).
At 1.5 bar the pump delivered 180 LPH and at 1.0 bar the pump could deliver 300 LPH of water flow.
For our community projects executed by Malati Vaidya Smruti Trust and Water Group, we often need data collected from various locations like lat long and dimensions of an existing bandhara wall (weir) on a river, or sequencial path of lat long points from a borewell to a nearby school.
This data can be captured on smartphones which are commonly available with local people nowadays, using various apps like My Tracks. But most such apps need the internet / data connection to be always enabled / available on the phone. At most of the locations which are remote areas, mobile network and data connectivity are not available.
मालती वैद्य स्मृती ट्रस्ट आणि वॉटर ग्रुपद्वारे राबविल्या गेलेल्या आमच्या सामुदायिक प्रकल्पांसाठी आम्हाला अनेकदा वेगवेगळ्या ठिकाणांहून माहिती गोळा करावी लागते जसे की एखाद्या अस्तित्त्वात असलेल्या बंधाराच्या भिंतीच्या जागेवर जाऊन त्याची लांबी, रुंदी, अक्षांश आणि रेखांश नोंदी घेणे किंवा एखाद्या बोअरवेलपासून शाळेपर्यंतचा मार्ग आणि त्यावरील नोंद करावयाचे अक्षांश आणि रेखांश.
माय ट्रॅक्स सारख्या विविध अॅप्सचा वापर करून आजकाल स्थानिक लोकांकडे सहज उपलब्ध असणाऱ्या स्मार्टफोनमध्ये हा डेटा नोंद केला जाऊ शकतो. परंतु अश्या बर्याच अॅप्ससाठी फोनवर उपलब्ध असलेले इंटरनेट / डेटा कनेक्शन गरजेचे असते. दुर्गम भागातील बर्याच ठिकाणी, मोबाइल नेटवर्क आणि डेटा कनेक्टिव्हिटी उपलब्ध नसते .
This requires that there needs to be some offline data collection mechanism, which will also allow submitting the data to central data server/repository whenever the data connectivity is available.
या समस्येवर मात करण्यासाठी एखादी ऑफलाइन डेटा संकलन प्रणाली असणे आवश्यक आहे, ज्याद्वारे जेव्हा कधी डेटा कनेक्टिव्हिटी उपलब्ध असेल तेव्हा ऑफलाईन पद्धतीने नोंद केलेला डेटा सेंट्रल सर्व्हर/रेपॉजिटरीमध्ये पाठवता येऊ शकेल.
We find that, ODK collect – which is a free to use app, can be the most (if not the best) suited and user friendly option for this purpose.
थोडी शोधाशोध केल्यावर आम्हाला असे आढळले की, ओडीके कलेक्ट – जे वापरण्यासाठी विनामूल्य आहे, या कामी बरेचसे योग्य आणि वापरकर्त्यांच्या दृष्टीने अनुकूल पर्याय होऊ शकते.
Pre-requisitesfor the End User
साधारण वापरकर्त्यांसाठी पूर्वतयारी
End User is a person who will be given the task of capturing data using the forms created by admin user.
User should have an android based smartphone with mobile data or wifi connection that has to be operational from his home or one such place.
User needs to have created his Google email id and it needs to be active.
Google drive app installed on phone.
ODK Collect app installed and configured on phone.
साधारण वापरकर्ता ही अशी व्यक्ती आहे जी उपलब्ध फॉर्मचा वापर करुन माहिती संकलनाचे (डेटा कॅप्चर) काम करील.
वापरकर्त्याकडे मोबाइल डेटा किंवा वायफाय कनेक्शनसह Android आधारित स्मार्टफोन असावा. डेटा /वायफाय कनेक्शन त्याच्या घरातून किंवा किमान एका तरी ठिकाणी कार्यरत असणे गरजेचे आहे.
वापरकर्त्याने त्याचा Google ईमेल आयडी तयार करणे आवश्यक आहे आणि ई-मेल सक्रिय असणे आवश्यक आहे.
फोनवर Google ड्राइव्ह अॅप इन्स्टॉल केलेले पाहीजे
ओडीके कलेक्ट अॅप फोनवर स्थापित आणि सेट-अप केलेले पाहीजे.
Setting up ODK Collect App (All Users)
ODK कलेक्ट अॅप सेट अप करणे (सर्व वापरकर्ते – साधारण तसेच अॅडमिन वापरकर्ते )
These steps, as a part of Setting up ODK Collect app, require data connectivity enabled on your mobile phone.
On your smartphone go to Play Store, Search app by name ODK Collect, Download and install the app.
When the ODK Collect app is started it will show its home page as below.
ओडीके कलेक्ट अॅप सेट-अप करताना आपल्या मोबाइल फोनवर डेटा कनेक्टिव्हिटी सुरू केलेली असणे आवश्यक आहे. आपल्या स्मार्टफोनमध्ये प्ले स्टोअरवर जा, ओडीके कलेक्ट नावाचे अॅप शोधा, अॅप डाउनलोड करा आणि इन्स्टॉल करा. जेव्हा ओडीके कलेक्ट अॅप सुरू होईल तेव्हा खालील प्रमाणे मुख्य पृष्ठ दिसेल .
In right top corner menu of the app, you can see options as below.
Select General Settings
Select option Server
Select Type and Choose the value Google drive,Google sheets
Select option Google account and when prompted choose or type your Google email id.
In General Settings select Option User and device Identity, a new page will show up as below.
In this page select option Form metadata
A new screen will show up, in this screen select options User Name, Phone Number, Email Address one at a time and set correct values for each of these three parameters.
For user name make sure that your name (say first name and last name seperated by space or underscore character) will not duplicate with any other person’s name working on the same survey.
Include underscore or suffix (say 2001) or simply enter your Gmail id in the User Name field, so as to always make sure of it to be unique.
The fourth parameter is Device ID, let the value whatever it is set on this parameter as a defualt, be left as it is.
Fetching Form Master Data (End User)
Fetching Form Master Data requires data connectivity enabled on your mobile phone.
After the ODK Collect app is configured as given in previous step, then on the main page of the app click button Get Blank Form.
It will show a popup message with some text saying Reading Files.
After some time it will show contents of the Google drive for you as the Google drive user. If you are a form designer yourself and if you have created any forms, then the same will be shown here in the list.
In the lower side buttons click Shared with Me, this is required so as to get access to forms that other form designers / admin users may have shared with you.
Once clicked it will show Reading Files message.
Then it will show the list of files available /accessible to you as may have been shared with you.
It will show Files and Folders shared with you by other Google Drive users. A form file is most often a .xml file, as seen in few samples in the above image. Please contact your team lead / admin user in your group who can give you the exact names of the working forms for getting access to those forms.
Once the form name/form file name is know to you, select the form file on which you have been asked to capture the data, and then click Download Selected button at lower part of screen. It will show some saying – Fetching files, let it complete the processing.
After successful fetching of the form, it will show success message as below.
Capture Data At Actual Site Location (End User)
Data capture work can be performed entirely in offline mode and network connection and mobile data on the phone is not necessary.
If the survey includes any questions or data elements to capture Geo Location point (lat long) then GPS on the phone MUST BE enabled with high accuracy.
On main page of the ODK Collect app, click Fill blank form button. On the following page the forms fetched/downloaded so far will be displayed.
Select a form that you want to use for data capture, then the app will go on asking questions from that form sequentially, and it will allow navigation through the questions.
Questions and their response entry fields are different based on each question type as may have been configured by the Admin User.
Please go on responding with appropriate answers till the end.
Answer/response to some of the questions may be mandatory so user can not go to next question untill values are captured.
A single Geo location point where latitude and longitude needs to be capture will appear something like below.
With GPS enabled on your phone, wait for some time till the accuracy improves to 2 or 4 meters or better and then click Save GeoPoint button. Image shown below only a sample, and was captured indoors when no GPS satellite was accessible to the phone, hence it shows very poor accuracy of more than 20 meters.
Once saved the GeoPoint will appear like below, after ensuring the accuracy value, proceed to Next or capture the point again by clicking the button Change Location.
Next sample question is for capturing a GeoTrace (multiple Geo points).
Most likely if mobile network and data connection is not available then the map may not show at all or will show with very coarse resolution, refer next image.
It is important to use the correct method for capturing the points in a Geo Trace. By clicking the first icon with + sign, at the right side edge of the page, select the Automatic location recording option, specify values for Recording Interval and Accuracy Requirement as shown and then click Start.
This is to be used while the end user walks around the object / entity being surveyed. For example if the user is capturing the GeoTrace near an open-well or a river, then the user needs to walk around the boundary with the auto option enabled. You can see that the ODK Collect app will record points continously every 10 or 20 seconds.
Once the boundary of interest is traversed as adequate then click the lowermost option for save which shows a disk icon.
After save click the values captured are displayed in a page like below.
Go throgh all the questions in the survey and capture the data to the fullest possible detail and accuracy. Please follow the instructions that may have been included by the Admin User for each question.
There can be various question types included in the survey as below.
Lat long – GeoPoint
Lat long list – GeoTrace
At the end of the survey questions the ODK Collect app will show a button Save Form and Exit, click that button to save the data captured.
Until so far the data captured is on the user’s phone and yet to be sent to the central common data repository/storage.
Send Form, Submit Data (End User)
Once you are done with the data capture as above you can / should submit the data.
For this you need mobile/data connection on your phone.
This activity can be performed from any location other than the survey site where mobile network or wifi connection is available and enabled on your phone.
Once your phone gets the data connection, then on main page of the ODK Collect app, click Send finalised form button..
It will show a page where all the form which can be submitted will be displayed. Select one or more forms which are ready to submit and click Send Selected button.
It will show Sending Form message, and finally it will show success.
Form submission success.
If any error occurs, please take a screenshot on your phone and send it to the admin user or entire team, so that suggestion about what to do on such error can be given.
User can view all the submitted/sent forms. By clicking the button View Sent Form on the home page of the ODK Collect app.
Any of the sent forms can be selected/touched/clicked and in the next page the app will show list of all questions in that form with captured data / answers shown briefly.
Pre-requisites for Survey Admin user
Admin user is a person who will prepare the survey questions and release the survey to the end users for data capture.
For each form to be used for data capture, below are the pre-requisites for admin user, these are in addition to all the prerequisites as applicable to the End User.
Create a blank Google spreadsheet in Google drive.
In Google Drive share the spreadsheet to all the data capture users, by adding their Google email Id.
Note down / copy the sharable URL of the spreadsheet file.
Create a Form layout using online form builder utility at this web site https://build.getodk.org/ This will require a login user id for yourself to be created first time.
Add the desired type and sequence of various questions.
Include the meta data system fields like user and phone number.
Specify the spreadsheet URL in the form properties – submission URL of the newly created form. Each form must have a different and distinct spreadsheet associated with it.
Export the form to local filesystem as XML format
Upload the form XML file in the Google drive.
In Google drive Share the form XML file to all the data capture users, by adding their Google email Id.
Avoid modifying the form design once the form is released for data capture and some data is already captured by the End Users.
If an existing form must be modified, deleting or renaming any existing question / field shall be avoided. Label and captions can be altered.
If a new question / field is to be added then corresponding field name must be added to the data capture Google spreadsheet as a new column after all existing columns and name of the new question / field needs to be manually entered as column label.
It is an interactive user interface for creating a data capture/survey form with various types of input fields or survey questions that can be added to the form. The instructions for form creation are not given here in details, and admin users are encouraged to explore the form builder web page, use the online documentation / help and get started with real forms that they want to create.
It is seen that it is best for the Admin users understand the form builder by doing hands on work.
Overall – How it Works / Conceptual Details
So far the activities to be carried out by End User and Admin User were exaplained.
For a given form, it may be so that one or more users are asked to capture data using the same form but for various different survey objects (locations or sites), as below.
User 1 – Location 1, Location 2
User 2 – Location 3, location 4 and location 5
User 3 – Location 1, location 3 and location 6
The data captured by multiple users as above will result in 8 instances of the same form captured on 3 different mobile phones of the 3 different end users. Notice that for Location 1 and Location 3 two different users were asked to capture the data, this may be intentional or otherwise.
All this data gets saved into respective mobile phones and when forms are sent by the users, it gets saved on the Google drive of the form creator user in a structured manner. There will be 2 each responses /datasets captured for Location 1 and Location 3, whereas other locations will have only one dataset.
The data captured from all users after they sent their respective forms needs to be programmatically fetched and interpreted, organized, processed and saved into some databse where it can be displayed or represented in a manner required by the project team.
With a question of type GeoTrace below processing can be useful to better understand the data captured.
To display the set of points as a track on Google map for all the points.
To calculate the perimeter distance and area of the boundary identified by the points.
To group various survey objects (say water-bodies) by their range/span of GeoTrace values.
All of the above.
We are in process of implementing a utility which can do such type of data processing using the data collected in ODK forms.
This will be deployed in our web site https://www.pbodas.in/ and will be made available to the logged in users. The users will need to permit the portal to access their respective Google drive files.
ODK Collect also works with a backend server instead of Google sheets, but that most often is a paid option which requires some server hosting and associated infrastructure management. Using Google sheets as the data capture mechanism is easier and free of cost as of now. Hence the same is highly recommended for community work and projects.
Please use ODK Collect app as explained above and provide your comments / feedback on this article.
सोलर पॅनल च्या सहाय्याने वीज निर्मिती करून त्या विजेचा वापर घरामध्ये करता यावा यासाठी महावितरणच्या नेट मीटरिंग पॉलिसीनुसार प्रकल्प सुरू करणे.
विजेचे बिल जवळपास शून्य रूपये (स्थिर आकाराव्यतिरिक्त – वहन आकार, वीज शुल्क इत्यादी घटक धरून) यावे यासाठी सोलर पॅनेल्सची आवश्यक ती क्षमता ठरविली जाईल.
प्रकल्प उभारण्याचा प्रारंभिक खर्च पार्टिसिपेटरी पद्धतीने केला जाईल. त्यासाठी सेवाभावी संस्था आणि ज्या घरांमध्ये वीज वापरावयास द्यावयाची आहे त्यांच्याकडून काही प्रमाणात निधी उभारला जाईल.
प्रकल्पाचा दरमहा येणारा खर्च (यामध्ये प्रामुख्याने महावितरणला भरावयाच्या वीज बिलाची रक्कम समाविष्ट आहे) वापरकर्त्यांकडून भागविला जाईल. या प्रकल्पामध्ये बॅटरीची आवश्यकता नसते त्यामुळे दर दोन-तीन वर्षांनी बॅटरी बदलावी लागते तो खर्च इथे लागू होणार नाही.
या प्रकल्पाचा फायदा असा की वापरकर्त्यांना विज बिल खूप कमी येईल आणि त्यामुळे वीज बिल भरण्याची टाळाटाळ करण्याचे प्रमाण बरेच कमी होईल, अशा पद्धतीने हे महावितरण साठी सुद्धा सोयीचे राहील.
दोन किलोवॅट इतक्या क्षमतेचा सोलर नेट मीटरिंग प्रकल्प करावयाचा आहे. याचा खर्च साधारणपणे ९० ते ९५ हजार रुपये इतका होतो, यामधून दरमहा 210 युनिट इतकी घरगुती वापराची (सिंगल फेज) वीज उपलब्ध होते.
महावितरणच्या LT I (B): LT Residential या टेरीफप्रमाणे 210 युनिट साठी एकूण बिलाची रक्कम 1441 रूपये अधिक 102 रुपये स्थिर आकार (1543 रूपये) इतकी होईल. प्रतिवर्षी वीज बिलामध्ये 17292 रुपयांची बचत होईल.
या हिशोबाने प्रकल्पाचा खर्च साधारण साडे पाच वर्षांमध्ये वसूल होईल आणि त्यापुढे 18 ते 20 वर्षे मोफत वीज उपलब्ध होत राहील, यामध्ये महावितरण’कडून येणारे वीज बिल (ज्यामध्ये प्रामुख्याने फक्त स्थिर आकार असेल) मात्र दरमहा भरत राहावे लागेल.
प्रकल्पासाठी लागणाऱ्या सामग्रीचा तपशील
या प्रकल्पाकरीता खालील घटक / सामग्री / यंत्रणा आवश्यक असतात, दिलेली किंमत २ किलोवॅट क्षमतेसाठी आहे
सोलर पॅनेल्स – ४६००० रुपये
ग्रीड टाय इन्व्हर्टर – २३००० रुपये
वाहतूक खर्च – ४००० रुपये
विजेचा मीटर (नेट मीटर आणि जनरेशन मीटर) – ६००० रुपये
एम सी बी स्विचेस, केबल्स, इत्यादी – ७००० रुपये
पॅनल बसवण्यासाठी आधाराचे स्ट्रक्चर – ३०००
वीजमंडळाची वाढीव लोड फी, सोलर अर्जाची फी आणि मीटर तपासणी फी – ५००० रुपये
इंस्टॉलेशन चार्जेस – सहभागामधून करावयाचे असल्यामुळे ० रुपये धरले आहेत.
ह्या प्रकल्पामध्ये बॅटरी नसते म्हणून बॅटरीचे पाणी तपासणे किंवा तत्सम दुरुस्ती लागू होत नाही. तसेच दर २ ते ३ वर्षानी बॅटरी बदलण्याचा खर्च करावा लागत नाही.
पॅनल वर जमा होणारी धूळ १०-१५ दिवसामधून एकदा सकाळच्या किंवा संध्याकाळच्या ऊन कमी असेल अश्या वेळी पाण्याने धुवून काढायला हवी.
दगडफेक आणि चोरी यापासून पॅनलचे संरक्षण करायला हवे. ह्या प्रकल्पाच्या उपयोगितेच्या अनुभवातून सामाजिक जाणीव निर्माण होईल तसतसे हे प्रकार बंद होतील.
याव्यतिरिक्त कुठलाही देखभाल दुरुस्तीचा खर्च नाही .
मोठ्या कुटुंबासाठी, ज्यांची २ – ३ – ४ स्वतंत्र घरे आहेत परंतु जवळजवळ किंवा एकत्र असतील त्यांनी हा प्रकल्प राबवल्यास एक विजेची जोडणी सोलर प्रकल्पासह घ्यावी. जेथे दरमहा विजेचा वापर खूपच कमी किंवा नगण्य असेल तेथे हा प्रकल्प तितकासा किफायतशीर होणार नाही. साधारणपणे दरमहा १८० किंवा अधिक युनिटे वापर असेल तर हा प्रकल्प खूपच सोयीचा आहे.
प्रकल्प बसवण्याच्या खर्चाची रक्कम योग्य आणि शक्य त्या मार्गाने गोळा करून प्रकल्प कार्यान्वित करता येईल.
त्यानंतर दरमहा वीजमंडळाकडून बिल येईल ते वापरकर्त्यांनी विभागून वाटून घ्यावे आणि बिल भरणा करावा.
वीज बिलाची रक्कम कशी ठरविली जाते?
त्या त्या महिन्यामधे सोलर पॅनल मधून निर्माण झालेली वीजेची युनिटे आणि घरामध्ये प्रत्यक्ष वापर झालेली वीजेची युनिटे यामधील फरकानुसार बिल ठरविले जाते.
एखाद्या महिन्यात वीजनिर्मिती जास्त झाली आणि विजेचा वापर कमी झाला तर जास्तीची युनिट आपल्याला पुढच्या महिन्यात वापरण्यासाठी उपलब्ध होतात.
Internet of Things (IoT) is about connecting various devices (sensors, controllers, display units, alarms and any such instrument/equipment) with each other using public internet and may partly run through private network of the end user.
With this primary capabaility, IoT opens out many opportunities for systems control, remote data monitoring and to execute commands that carry out various operations based on desired conditions.
With improved data connectivity and availability + the reducing prices of electronic devices, IoT is picking up fast and more importantly it is also getting easier for hobbyists and individuals to deploy IoT projects all by themselves.
Besides the hardware and software to implement any IoT project, what is equally important is a consistent and fairly reliable mechanism to receive and store the data points in a (near) real time manner.
Setting up such a data store can turn out costly, but there are many such online services available. For industry grade volumes and quality of service/reliability, such data logging services providers offer various plans with different charge structures.
For hobbyist and DIY users, most if not all these online services offer a free option but obviously with limited resources granted to the user.
A few of the popular service providers are listed below, this is just a very small list.
Let us see how to open an account and create a data logging channel with one of the service providers, namely thingspeak.com
Create an account with ThingSpeak
From your computer or mobile phone connected to internet, open the web browser and go to the URL link ThingSpeak SignUp
Enter your email address and Country and First Name, Last Name on the sign-in page, then click Proceed / Next / Continue button. We recommend using the same personal Google email id as you use on your mobile phone google account.
It will warn you about your email address being personal email id. Refer the image below. Please Tick / Select the check box near Use this email… and click Continue button. After this it will display a message mentioning about having sent a link to your email address.
Open your e-mail box and find the mail received from ThingSpeak, check if the email has gone into spam folder. Please ask for resending the mail again, if required, by clicking the Send Me the Mail Again link.
Locate the URL link available in the email that you received and click the link or button or copy paste that URL link in a new browser tab/window. Please keep the previous tab/window of ThingSpeak still open for further use.
This new tab/window (not shown here) which you opened from your email by clicking the verification link / button – will show some message like your account/email after successful verification. This is actually a mathworks account which is another website like ThingSpeak, both of which share common authentication and some other such few features.
After this verification is successful, resume in the previous ThingSpeak tab/window, by clicking the Continue button.
It will take you to sing-up page where you will be asked to specify your user id and password for ThingSpeak login. Please set a valid user id and password for your ThingSpeak account, this is entirely different and not connected with your email address. Remember and/or note down the user id and password for future use.
Then proceed to login to ThingSpeak web site or you will be automatically logged into ThingSpeak.
At the first login it may ask for some additional information like – what purpose you plan to use ThingSpeak for, (refer next image). Please specify non-commercial/ personal use and click ok.
A channel is one identifiable register/data store to capture data.
For example let us say – a user has 2 different locations where he /she wants to monitor the ambient temperature and humidity at every 5 minutes continuously.
To be able to do this the user will setup the needed sensors at the respective locations and data acquired by the sensors will have to be posted to some internet based URL. This URL will receive the data values and store them for later use and analysis.
For this example, the user needs to have two different registers or data stores one per location and each register needs to support at least three fields (namely timestamp, Temperature in deg C., Humidity in %).
So it is like two readings one each for the two locations, comprising of 3 field values each will be received and saved every 5 minutes. That is 576 readings per day and over 2 years it will be around 0.42 million or 420000 readings. Each reading is about 40 bytes say, so just 16 MB of data over 2 years. The data volume for these two datastores is not really that high, but it is important that the datastore has to provide a reliable and continously available mechanism of data logging.
When translated in the terminology of ThingSpeak, this means two channels one each with 3 fields of data are necessary to be created.
Thingspeak allows upto 4 channels to be created by every user having a free account.
So let us see how to create a channel.
After the ThingSpeak login account has been created and successfully logged in, it is required that a new channel be created in the page shown below.
Click the New Channel button, the website will take you to next page.
On this page specify a channel name and select / tick against all the 8 fields shown in the page. Then click Save Channel button. There are other two buttons provided as below
Clear Channel – This clears the old data that may have been captured so far in this channel. It is recommended to not clear the channel unless you are sure that you want to lose the data forever.
Delete Channel – This deletes the channel altogether. It is strongly recommend to not click this ever, especially after any of the field device is using the channel.
Important Parameters of the Channel
Please note down the Channel Id, Name and Read and Write API Keys, as it shows in the web page in the API Keys tab. Once the channel is created the Keys and Channel Id can be used by any device/software so that the data to be collected by any field sensor or device can be posted to the channel. These values can be altered any-time by the the user login who created the channel, but if the channel keys are setup in any IoT device as a part of one time configuration then the altered values (especially the Read and Write API keys) need to be updated in all the devices and programs where the old keys were used.
Verifying the channel
Once the channel is created it can be tested by executing below commands in browser address bar.
Write to Channel https://api.thingspeak.com/update?api_key=WRITE_KEY&field1=123456&field2=0.56
The above comamnd submits and saves one data point with values of two fields to the respective thingspeak channel with matching WRITE_KEY.
This comamnd retrieves 20 data point from the thingspeak channel specified by the CHANNEL_ID
View the data graphically
Thingspeak provides a nice and simple way to view the datapoints. It would be a good activity to explore this part in details to understand what options it gives to view the data, i.e. various types of graph, number of datapoints to be viewed etc. https://thingspeak.com/channels/CHANNEL_ID/private_show
Since the concept was posted in the previous blog Mini Weather Station, many friends and readers reverted with various points and questions.
Trying to address them here.
Open for comments and more questions please….
Why DIY Weather station
Do It Yourself gives a full control and understanding about what and how a certain thing is being implemented and it gives a very good hands on experience. Starting with concepts till actual deployment of the gadget, a DIY weather station is your own mechanism to accurately and directly measure and record the climate and climate changes in your area.
What all you need, is below…
A ventilated outdoor space, it can be a balcony / terrace, but no direct sunlight and no direct rainfall, at least where the device will be mounted.
A continously available WiFi data network.
Source of electricity to power the device.
Enthusiasm to participate in climate change and related activities.
Weather already on my cell phone.
Yes, smartphones of current generation do have some kind of temperature and weather data displayed on the home screen.
Even if there is one such sensor, the temperature displayed from time to time will be at various places including indoor and outdoor as the phone is carried along by the user. And we want to record and track the weather conditions at a specific open ambient place.
On most common phones i.e. without a temperature sensor as a part of their hardware, the displayed value is often fetched from some weather services website like AccuWeather
Real time data shown from such websites is a fairly complicated calculation, which involves the actual readings from the nearby weather stations (official, public, private, owned by government bodies or institutions) + the data continuously recorded by weather satellites at various locations. Weather satellites donot measure actual temperature but infer the values based on infra-red scanning of the earths surface. How does weather satellite work
So the correctness of the temperature displayed on the home screen of your phone is dependent on several factors like the distance from the nearest weather station and weather satellites.
Also it is important that we should be able to record data at regular intervals and later be able to compare the values year over year in form of daily, weekly, monthly and yearly min,max and average/median temperatures. Most weather services websites donot provide historical datapoints easily and free of cost.
There are not many known/closely located weather stations in India, or at least information about them and their readings are not published.
Looking at all the above points, it will be meaningful to have more weather stations through public participatory approach at various places. The data can be valuable in terms of analysing the effect of trees, water bodies, streets congested with traffic, and seasonal changes on the ambient temperature.
Why invest in a weather station?
This is purely optional and voluntary. If anyone wants to participate, it is for his/her own interest in and commitment towards protecting the environment and addressing issues related to the environment. There are many many ways in which efforts can be put in to preserve our environment. Participating in this weather station initiative is just one of them.
The cost of components used in the DIY weather station is about 1100 to 1300 INR. We are happy to assemble/package the components in a working unit and provide to the participants willing to install at their place. The recurring cost of operations is mainly in two parts.
Cost of the wifi data – It is estimated that the unit will post 100 characters of data over your local wifi connection every 2 to 5 minutes, that is about 72KB of data per day, lets say not more than 1 MB per day. This is really not much of data for an existing internet connection. With current data quota values supported by most of the broadband and mobile service providers, this is not likely to incurr any additional costs.
Cost of electricity to run the device – It is measured to consume between 2 to 3 watts of electrical power continuously, this means that within 14 to 20 days of operation the device will consume 1KWH unit of electricity, amouting to about 4 to 8 INR, which means an additional monthly electricity bill of about 10 to 12 INR
Don’t have a WiFi connection
In such a case, a dedicated mobile-SIM based data connection with a WiFi dongle can be arranged, but that will mean additional costs.
One time cost of the dongle device – approximately 1000 INR for most service providers.
Recurring monthly cost of service provider – It is approximately 100 INR at a minimum with most of the service providers in India. If there is any service provider which supports much lesser monthly charges with low data quota per day (we are ok even at, as low as 10-20 MB per day, literally) then it will be more practical.
याआधीच्या भागामध्ये आपण घरगुती वापराच्या विजेच्या युनिट बद्दल माहीती करून घेतली. आता आपण पाहूया की सौर विजेचा पर्याय कसा काय आहे ते.
In previous articles we discussed about the units of electricity for household usage. Now we will see how can solar electricity be useful to us.
सोलर पॅनल वापरून वीजनिर्मिती करता येतेच, परंतु सौर ऊर्जेची उपलब्धता दर दिवशी आणि ऋतुमानाप्रमाणे बदलत राहते, इतकेच कशाला, निरभ्र लख्ख सूर्यप्रकाश देणारे आकाश केवळ ५ – १० मिनिटांमधे ढगांनी व्यापले जाऊन सूर्यप्रकाश अचानक कमी होतो. त्यामुळे सोलर पॅनेल्स मधून निर्माण होणारी वीज ही सततच सूर्यप्रकाशाच्या तीव्रतेनुसार कमी जास्त होत राहणार. थोडक्यात काय तर सौरविजेची उपलब्धता आणि आपल्या घरामध्ये त्या त्या वेळी किती वीजवापर सुरु असेल ह्या दोन गोष्टींचा ताळमेळ राहात नाही. याउलट वीजजाळ्यामधून आपल्याला हवी तेव्हा आणि हवी तितकीच वीज वापरायला घेता येते.
Though it is very much possible to generate electricity using solar panels, the instantaneous availability of solar electricity varies every day and across seasons. In fact even on a given day, the clear sky can suddenly turn cloudy and due to reduced sunlight, the solar electricity generation will come down. Thus the solar electricty generated at any time will keep fluctuating based on sunlight. In short there is very less likely to be a match between the solar electricity generated and the electricity needed for consumption. On the other hand if we consume electricity from the electric grid, it can, at all times, supply as much and only that much electricity being consumed.
उदारणार्थ खालील आलेखामध्ये सकाळी साडेसात वाजल्यापासून सायंकाळी साडेपाच वाजेपर्यंत सौरवीजनिर्मितीचे प्रमाण पहायला मिळते आहे. एकतर सूर्य जसा डोक्यावर येऊ लागतो तसे निर्मिती वाढते, परंतु अधूनमधून ढगाळ हवामानामुळे वीजनिर्मिती अचानक कमी झाल्याचे स्पष्टपणे दिसते आहे.
दिनांक – ३० सप्टेंबर २०२० / Date – 30-Sep-2020
ठिकाण – ठाणे ४००६०२ / Place – Thane 400602
सौर पॅनल क्षमता – ४८० वॅट / Solar Panels Capacity – 480 watt
उभा अक्ष – य – वीजनिर्मिती वॅट मधे / Vertical Axis Y – Electricty generated Watts
आडवा अक्ष – क्ष – वेळ तास:मिनिटे / Horizontal Axis X – Time HH: MM
The graph shows how the solar electricity generation varies over time on a typical day.
सौरवीज आणि वीज जाळ्यातली (ग्रीडमधून मिळणारी) वीज ह्या दोघांमध्ये हा मुख्य फरक आहे – हा मुद्दा सतत लक्षात ठेवावा लागतो .
म्हणून सोलर पॅनल मधून निर्माण होणारी वीज साठवून ठेवण्याची आणि नंतर आवश्यकतेनुसार वापरायला मिळेल अशी काहीतरी सोय अत्यावश्यक आहे.
Solar electricity and grid electricity are drastically different from each other in this aspect of availability. and this point needs to be remembered at all times.
Hence it is required that there has to be a way to store electricity generated from solar panels and later make it available for use when needed.
वीज साठवण्याचे सोपे साधन म्हणजे बॅटरी किंवा विजेरी.
ह्यामध्ये वेगवेगळ्या रासायनिक द्रव्यांचा अथवा संयुगांचा आणि काही ठराविक धातूंच्या पट्ट्यांचा वापर करून वीज साठवण्याची क्षमता निर्माण केलेली असते.
बॅटरी चार्ज केली जाते तेव्हा बाहेरून पुरवलेली वीज / विद्युत प्रवाह वापरून एका विशिष्ठ प्रकारची रासायनिक अभिक्रिया होते आणि बॅटरीमध्ये ऊर्जा साठविली जाते. याउलट जेव्हा बॅटरीद्वारे एखादे विजेचे उपकरण चालवले जाते तेव्हा विरुद्ध प्रकारची रासायनिक क्रिया होते आणि बॅटरी डिस्चार्ज होते किंवा उतरते. जेवढी ऊर्जा साठवलेली असेल त्याप्रमाणात ऊर्जा वापरायला घेऊ शकतो.
ह्या प्रकाराला चार्ज आणि डिस्चार्ज सायकल असे म्हटले जाते.
साहजिकच जितक्या मोठ्या प्रमाणात वीज साठवून ठेवायची असेल तितकी मोठ्या आकाराची (आणि किमतीचीदेखील) बॅटरी वापरणे आवश्यक असते. कुठल्याही बॅटरीचा महत्वाचा भाग हा असतो की – बॅटरी पूर्णपणे निरुपयोगी होईपर्यंत किती वेळा चार्ज आणि डिस्चार्ज करता येईल. बॅटरी बनवण्याच्या तंत्रज्ञानानुसार आणि प्रकारानुसार ज्या काही चार्ज-डिस्चार्ज सायकलची संख्या शक्य असते तितकी वापरून झाली की बॅटरी निकामी तरी होते किंवा अतिशय कमी क्षमतेने काम करू लागते.
चांगल्या दर्जाच्या बॅटरीला चार्ज-डिस्चार्ज सायकल खूप जास्त असायला हव्यात.
आजकाल विविध प्रकारच्या बॅटरी उपलब्ध आहेत.
त्यामध्ये बऱ्याच काळापासून स्थिरावलेला आणि प्रचलित प्रकार म्हणजे लेड एसिड बॅटरी –
ही खूप जड आणि जाड असते, द्रवरूपात आम्ल भरलेले असते त्यामुळे जेथे बॅटरी एकाच ठिकाणी कायमस्वरूपी ठेवायची आहे फक्त तेथेच ही सोयीची होते. तुलनेने किंमत कमी आहे, परंतु हिचे आयुर्मान / चार्ज-डिस्चार्ज सायकल्स सुद्धा कमी असतात.
दुसरा अलीकडच्या काळात प्रचलित होत असलेला प्रकार म्हणजे लिथियम बॅटरी, वजनाने हलकी आणि जास्त आयुर्मान – अर्थातच महाग.
The commonly known approach to store electricity is a battery which is based on chemical reactions between metals/non-metals and acid or such liquids. During the charging process a specific chemical reaction happens and electric energy is stored in chemical form. Later when the electricity is consumed, a reverse chemical reaction occurs and battery discharges or drains.
Such a process is called as one charge-discharge cycle. After the permissible charge-discharge cycles are exhausted, the battery goes almost dead/useless and needs to be replaced.
Obviously a good battery needs to have large number of such charge-discharge cycles and it needs to have large enough the storage capacity based on usage requirements.
There are two popular battery types
Lead Acid: An old timer, heavy, contains acid in liquid form, good for stationary applications, relatively lower priced but also less number of charge-discharge cycles.
Lithum Based: Relatively new, light weight, usable on the move, costlier but also supports more charge-discharge cycles.
बॅटरीच्या क्षमतेकरीता विद्युतभार (व्होल्टेज) आणि प्रवाहक्षमता (अँपिअर-अवर ) अशी दोन परीमाणे प्रचलित आहेत.
उदाहरणार्थ : घरातील इन्व्हर्टर साठी १२ वोल्ट आणि १८० अँपिअर-अवर ची एखादी बॅटरी सामान्यतः बसविलेली पाहायला मिळेल.
सोप्या भाषेत सांगायचे तर अशी बॅटरी १२ वोल्टवर चालणाऱ्या उपकरणामधून १८० अँपिअर इतका करंट एक तासभर प्रवाहित करु शकेल.
किंवा १८ अँपिअर १० तासाकरिता
किंवा २ अँपिअर ९० तासाकरिता
आणि अश्या प्रकारे १२ x १८० = २१६० वॅट अवर = २.१६ के डब्ल्यू एच (KWH) इतकी विद्युत ऊर्जा ही बॅटरी साठवून ठेवू शकेल आणि हवी तेव्हा पुरवू शकेल.
मात्र हे असे करताना बॅटरी चे एक चार्ज आणि डिस्चार्ज सायकल संपले असे होईल.
Typically a battery is specified by its voltage and current rating as an example, a household inverter battery would be a 12 VDC 180 Amp-Hour capacity. That means it can push 180 ampere current through an electrical appliance operating at 12V for one hour, or 18 ampere for 10 hours or 2 amperes for 90 hours.
This way such a battery can store and supply 12×180 = 2160 watt-hour = 2.16 KWH of electrical energy.
अशी एक बॅटरी घेऊन आपण तिला सोलर पॅनल मध्ये दिवसा सूर्यप्रकाशात निर्माण होणाऱ्या विजेने चार्ज करूया आणि सूर्यप्रकाश नसेल तेव्हा (सकाळी, संध्याकाळी आणि रात्री ) गरजेनुसार बॅटरी मध्ये साठवलेल्या विजेचा वापर करूया.
असे गृहीत धरलेले आहे की पॅनल मध्ये निर्माण होणारी वीज आणि आपल्याला दिवसाभरामध्ये संपूर्ण २४ तासांमध्ये वापरण्यासाठी लागणाऱ्या वीजेचे प्रमाण हे एकमेकांशी साधारणपणे मिळतीजुळते आहे /असेल.
आणि अशी ही बॅटरीवर आधारित प्रणाली / सिस्टीम दररोज आपल्याला वीजपुरवठा करीत राहील. दररोज २ युनिट इतका वीजवापर असेल आपल्या बॅटरीच्या ०.७५ ते १ चार्ज डिस्चार्ज सायकल दररोज वापरल्या जातील.
Let us consider that we take such a battery and set it up to get charged by solar panels in the daytime. We consume the stored electricity during the time when sunlight is not avaialble (early morning, evening and night). It is assumed that the battery and solar panels are so selected that the solar electricity generated and electricity needed for conumption is more or less matched to each other. If the daily consumption is 2KWH then such a battery would end up in depletion of its 0.75 to 1 charge-discharge cycles.
ह्यामध्ये समस्या अशी आहे की एका वर्षाच्या वापरानंतर सुमारे २०० ते ३५० चार्ज डिस्चार्ज सायकल संपून गेलेल्या असतील, आणि जरी ५०० सायकल क्षमतेची बॅटरी (लेड ऍसिड प्रकारातली ) असली तरीदेखील दीड ते दोन वर्षांमध्ये ती जवळजवळ निकामी होऊन नवी बॅटरी बसवायची (आणि तितका म्हणजे १०००० ते १५००० रुपये इतका खर्च पुन्हा करावा लागण्याची) वेळ येईल.
The problem is – after an year of usage in this way, the battry would have lost its 200 to 350 charge-discharge cycles, and even if a battery with 500 cycles is installed (typically a good quality and moderately costly variant) it will be almost dead within 2 years. Then it needs to be replaced at a cost of about 10000 to 15000 INR.
त्याऐवजी लिथियम प्रकारची बॅटरी असेल (जी सुमारे १५००-२००० चार्ज डिस्चार्ज सायकल देऊ शकते आणि निर्माते तरीही फक्त ३ ते ४ वर्षांची वारंटी/ग्यारंटी देतात) तर ती ५ ते ६ वर्षे वापरता येईल, आणि नंतर नवी बॅटरी बसवते वेळी लेड ऍसिड च्या तुलनेत ३ पट जास्त किमतीला घ्यावी लागेल.
If instead a lithum based battery is used (which has 1500 to 2000 cycles but still a warranty of 3 to 4 years) will run for about 5 to 6 years. And then when a new battery needs to be installed, it will cost almost 3 times more as compared to a lead-acid battery.
तात्पर्य – तर दीर्घकालीन विचार केल्यास बॅटरीवर आधारित सोलर विद्युत ऊर्जा प्रणाली आर्थिक दृष्ट्या परवडणारी नाही.
Conclusion : In long term a battey based solar electric system is not financial viable.
आपल्याला इमर्जन्सी म्हणून एखाद्या उपकरणाला वीजपुरवठा करणे गरजेचे असेल तर मात्र बॅटरी वर आधारित सिस्टीम वापरणे अपरिहार्य ठरेल.
As an emergency requirement if any device needs to be always up and running then a battey based system is an unavoidable option.
तर मग ह्याला एखादा चांगला पर्याय आहे का? पुढील भागामध्ये पाहूया.
So then is there any better alternative to this? we will see in next part.
घरात आपण वापरतो ती वीज आपल्याला वीजमंडळाच्या वीजजाळ्यातून (इलेक्ट्रिक ग्रीडमधून ) मिळते.
The electric energy that we use in our households is available to us from the electric grid of the supply company.
वीजजोडणी १ किंवा ३ फेज ची असते, साध्या वापरासाठी १ फेजचा वीजपुरवठा पुरेसा होतो, परंतु जास्त वापर करणारी उपकरणे जसे की मोठ्या क्षमतेचे पंप , यंत्रसामग्री इत्यादी साठी ३ फेज पुरवठा सोयीचा होतो .
The electric connection is either 1 phase or 3 phase, for small scale household usage single phase connection is adequate, but for large sized pumps and equipment a 3 phase supply is better and recommended.
आपण वापरतो त्या विजेचे बिल आपल्या वापराच्या युनिट नुसार वीजमंडळ दरमहा आपल्याला देते आणि त्याचा भरणा वेळेवर न केल्यास आपली विजेची जोडणी खंडीत करण्याचे अधिकार वीजमंडळास असतात.
The monthly electric bill is generated based on the units of electricity that we use, if not paid within stipulated time, the electric supply company can disconnect the electric supply to the consumer.
वीजवापर मोजण्यासाठी एक मीटर बसविलेला असतो आणि त्यावर आपल्या विजेच्या वापराची संख्या के-डब्ल्यू-एच (KWH) (सर्वसामान्यपणे युनिट असे म्हटले जाते) मध्ये सतत दाखविली जाते.
To measure the consumption of the electricity, an energy meter is installed at the premise of the consumer. On the display of this meter, the accumulated consumption of electricity is continiously displayed in KWH units.
आपल्या माहितीकरिता आणि कुतूहल म्हणून आपण आपल्या मीटर वर सतत दाखवल्या जाणाऱ्या आकड्यांचा परिचय करून घेतलेला बरा.
It is a good thing to know the location and details on the display of our own energy meter.
वेगवेगळ्या कंपन्यांचे मीटर थोड्या फार फरकाने विविध प्रकारची माहिती स्क्रीनवर एकामागून एक दाखवत राहतात – दिनांक, वेळ, आतापर्यंत झालेल्या वीजवापराची युनिटे अर्थात के-डब्ल्यू-एच (KWH)
Energy meters from various companies, with small differenece here and there, keep scrolling the information on the display – typically date, time, accumulated energy units KWH used so far till any given point of time.
आता थोडेसे विजेच्या परिमाणा-विषयी (युनिट)
Now let us understand the unit of electricity consumed
सर्व प्रकारच्या ऊर्जेचे परीमाण वॅट हे असते आणि किती वॅट ऊर्जा किती वेळासाठी वापरली ह्याचे परीमाण के-डब्ल्यू-एच (KWH) असे आहे.
All types of energies (rather power or the rate of consumption of energy) is Watt, and how much energy used for how long is often expressed as KWH units.
तर अश्या प्रकारचे १ युनिट म्हणजे नक्की किती ऊर्जा?
So how much really is a 1 KWH?
तर १०० वॅट चा एक दिवा १० तास सुरु ठेवला तर १ युनिट वीज वापरली जाते.
If we operate a 100 watt light bulb for 10 hours, it is 1000 Watt Hour or 1KWH.
किंवा १००० वॅट (१ किलोवॅट) ची इस्त्री १५ मिनिटे (एक चतुर्थांश तास) वापरली तर ०.२५ युनिट वीज वापरली जाते.
If we use an electric iron of 1000 watt capacity, for 15 minutes, then it is 1000×15/60 = 0.25 KWH units.
किंवा २००० वॅट चा पाणी तापवायचा रॉड हीटर अर्धा तास वापरला तर १ युनिट वीज वापरली जाते.
An electric rod type immersion water heater of 2000 watt if used for half an hour then 2000×0.5=1000 Watt Hour or 1 KWH units are consumed.
ह्या पद्धतीने आपण आपल्या घरातल्या विविध उपकरणांचा जितका वेळ वापर केला जातो त्यावरून विजेच्या युनिटांचा अंदाज किंवा गणित करू शकतो.
Going by this simple calculation we can determine the approximate consumption of electricity in our home on a daily or monthly basis.
वीजवापरासाठी वीजमंडळ वेगवेगळे आकार (चार्जेस) लागू करते ,जसेकी….
Electricity company charges various rates under different heads of charges as below.
स्थिर आकार – कितीही कमी अथवा जास्त वीज वापरली तरी ही ठरावीक रक्कम दरमहा बिलामध्ये घेतली जाते, सिंगल फेज साठी सध्याचा स्थिर आकार ८० ते ११० रुपये आहे.
Fixed Charges – No matter how much electricity the consumer uses in a month, this charge will always be applied in every bill. As of now this is 80 to 110 INR per month for a single phase connection.
वीज आकार – हा आकार मुख्यत्वे वीज वापरासाठीच आहे Electricity Charges – This is the charge directly applicable for the units of electricity consumed.
वहन आकार – मंडळाच्या वीजवाहिन्यांचे जाळे वापरून आपल्याला वीज मिळते, त्यापोटी द्यावा लागणार आकार Wheeling or Transmission Charges – This is in a way the charges for providing electricity at a location away from the point of generation, basically the transmission related charge/cost.
इंधन समायोजन आकार – इंधनाचे दर कमी किंवा जास्त होतात त्यानुसार हा आकार लावला जातो
Fuel adjustment charges – This is levied due to changes in the cost of fuel that goes into generating the electricity in the power plants.
वीज शुल्क – वीजवापराचे शुल्क
Energy Charges – Similar to electricity charges, but just a different charge head.
वीज विक्री कर – वीजविक्री करताना लावावयाचा कर Electricity Tax on Sale – Tax as a part of electricity sales by the supply company to the consumer.
ह्यातील स्थिर आकार वगळता इतर सर्व आकार वीजवापराच्या युनिट वर अवलंबून असतात, अर्थातच जितकी युनिट जास्त वापरली जातील तितके हे सर्व आकार त्या प्रमाणात लागू होणार.
Out of the various types of charges, all charges except Fixed charges are directly proportional to the units of electricity consumed. In a way these are all variable charges and will be higher in propotion to the units consumed.
त्यातही युनिटच्या पायरीपद्धतीने दर-आकारणी केली जाते ०-१०० युनिट ३ रुपये प्रति युनिट, त्यापुढील युनिट ला १०१ -३०० युनिट मध्ये गेल्यास ६ रुपये प्रति युनिट असे चढे दर लागू होतात.
Variable charges are mostly grouped in increasing slabs of consuption, e.g. 0-100 units 3 INR per unit, 101 to 300 units are charged at 6 INR per unit.
आणि ही दर आकारणी ग्राहकाच्या टॅरीफ (वीजदरतक्ता ) नुसार बदलते, साधारणपणे MSEDCL च्या सर्वसाधारण वीज ग्राहकाला 090 /LT-I (B) Residential 1Ph हा टॅरीफ लागू असतो, परंतु असे अनेक टॅरीफ नेमून दिलेले आहेत आणि त्या त्या प्रमाणे दर आकारणी केली जाते.
This actual rates of various charges are also dependent on the tariff category assigned to the consumer. As an example, for the standard residential consumer, MSEDCL in Maharashtra applies a tariff – 090 /LT-I (B) Residential 1Ph