Monday, December 1, 2014

Solar Project at Chandpur Village

The below post is about a recent project that our company executed in a remote village in Himachal pradesh . Most of the content below is copied from my company's blog. 

Chandpur is a small but beautiful village located in the army town of Palampur in the Kangra district of Himachal Pradesh. The linger leisure (lodge) has opened a facility there. It is situated in a valley about 8 Kms from the Palampur town. Its a beautiful lodge in the foothills of himalayas overlooking a beautiful stream of water.

Because of the terrain and the distance , there is no state power grid there. That is there is no electricity in the area. In this context ,Linger assigned us the work of designing and installing a solar power system for the facility.

The power requirement there was not much. It was just 6 rooms to be used only in the weekends. All the rooms had LED bulbs of 3 to 5 W. So, essentially we had to design a battery system to be charged from solar radiation to support all the loads in the weekend.

Technically this was not a challenge for us. This was a straightforward standalone system with very small capacity. Considering only weekend crowd and low loads and after discussing with the owners to optimize consumption, we arrived at a design of 500 Wp.  However, we had many other operational challenges like;
  • Distance: We are a Bangalore based company and the site was in Palampur 2800 Kms away in a remote village. 
  • Availability of material: The closest town to our site was Palampur. Though it is a Town/Taluk, we would not get either solar panels or batteries or inverter . We could not even get DC wires there. 
  • Terrain: The Site was 80 feet below and 500 feet away from the nearest road. The site had no access by road . There was no pathway as well. 
  • No Power: Obviously there was no power for the installation. 
  • Mud building: The lodge is built with locally made mud bricks and bamboo and the walls are finished with mud plaster (mixed with little cement and cowdung). Drilling or driving nails into these walls posed a challenge. The roof of the building was made of slate which is a brittle material. Slate roofing along with falling daytime temperature made working on the roof a challenge. 
  • Cost : We had a tight budget for the project.
Inspite of all the challenges, we decided to go ahead with the project. We badly wanted to do this project since this was our first project in North India. The non technical challenges added charm and adventure to the project. But how did we go about doing the project? 

The greatest challenge was to get the panels to the site. Nowhere in chandigarh and palampur we could find 250Wp panels. We had to transport the panels from Delhi. "Vikram Solar", one of the largest panel manufacturing companies in India had their office in New Delhi. We contacted them through our office in Bangalore and they gave us a good deal. But they would not transport the panelsWe tried through some of our contacts in Delhi to ship it to Palampur but of no avail. We contacted DTDC office in Delhi. They gave a very exorbitant quote. Somehow we agreed. But finally they also pulled out saying that it was a very fragile item to ship.

My colleague Kiran rao  was in Dharamshala for some work. He made a quick trip to Delhi to see how best he could ship the material. It was trouble for him throughout. He managed to somehow repack the panels. But the Vikram solar office was in South Delhi. He had to get to Kashmiri gate about 25 Kms through the heart of New Delhi and Old delhi to load the panels on the Bus. Each panel was 22 Kgs , 1.2 M in length and 1.0 M in width. The delhi traffic rules says that one cannot transport materials on the highway between 4 and 8 PM. Unaware of this rule, Kiran rao hired a small van to transport the panels. The van guy stopped half away and would not take the material further. 

So there was our Kiran in the middle of new Delhi with two heavy panels. No other transporter would oblige. At about 7 PM , kiran rao got a transporter with a special Pass. He finally landed at the bus stop at 8 PM. He left the panels in the bus stop and rushed to the hotel to check out. Thankfully the panels were intact by the time he returned but he missed the bus to Palampur. He had to get a Volvo bus only since the panels could fit only in its trunk. But there was no other Volvo bus.

Kiran made a bold decision to put the panels in a normal bus. He climbed the bus, put the panels and tied it up. Trusting god he set out to Palampur. The bus rolled into Palampur by 9 AM the next day. Kiran himself climbed the bus and unloaded the panels. The first thing he did was to check the panels with a multimeter if the bad roads had damaged the panels. Thankfully ,everything was intact . All the effort was worth it. The panels then were transported first by a Van and then it was carried by three men down the valley to the site.

The greatest task was achieved after much Drama. However, this was just half the work. We still had to get the tools, the inverter and the batteries. We shipped the battery operated tools from bangalore. We shipped the inverter too from Bangalore for a very huge price. The couriers did not reach the destination since it had to cross a military station. So Kiran rao had to pick up the consignments from the courier office in Palampur and take it to chandpur through the military station after giving declaration. The batteries came from Patankot. Udham singh, the local worker carried the 75 kilo batteries down the valley (2 of them).

We got the mounting structure fabricated nearby. But no one would paint it. So kiran himself painted it himself.

Kiran finally integrated all the items. The mud plaster gave a lot of trouble but also made the work aesthetically pleasing (It was very easy to camouflage the conduits).
There were some hiccups. Some tools were missing and some connectors failed. I was in Delhi on some personal work . I got in touch with a distributor in Delhi and got the connectors. I  made a trip to Palampur to close the project. 

Myself and Kiran hired a bike at Palampur. We got around the town and picked up all the electrical items required. We trekked down to the site with long conduits on our shoulders. The final touches were given . All the missing links were closed and the beautiful house deep in the hills of Himachal pradesh lit up on a chilling winter night.

It was a very very satisfying project for our team. But for Kiran Rao, we could never have completed this project. Kiran deserves full credit.

Thanks to linger and Kiran, we also got a chance to visit the beautiful towns of Palampur and Dharamshala. Thanks to Kiran and Linger, i got a chance to ride in the hills of Palampur and Mcleod Ganj. The ride, the landscapes, the paragliding , the birds, the hills ,the temples and of course the cute little project made a wonderful experience. 

Saturday, November 15, 2014

Just another one among us (Billion!!)

Linger at Chandpur, Palampur
We are such a diverse country with more than a billion people. Each state in our country is bigger and more diverse than many of the European countries.  Traveling in India is an amazing experience. The diversity in culture, tradition , customs , music, dance, cuisine, dressing, people, attitude , religion is mind boggling. It is a miracle itself that such diversity has come under one flag and one country. 

Last week , i was on a trip to Himachal pradesh. The beautiful landscaped country is well known for its majestic mountains and chilling winters. I visited three towns in the kangra district namely Palampur, Dharamshala and Mcleodganj. All are predominantly military stations with a small civilian population. Later two are also well known as spiritual centers for the presence of monasteries and chinmaya mission

Each of these towns have many villages under them. I had been to a village called Chandpur in Palampur. It is a very small village blessed with amazing diversity of flora and fauna (Like most places in Himachal pradesh). I stayed at a beautiful lodge called Linger in the mountain valley. Apart from the many birds and trees, i met many local people. I spent three days with a lovely family comprising of Uttam singh, his wife pavan and his kaku (i do not know kaku's name. I know him just as kaku). This is another beauty of this land. We do not need to know people's names. We can very quickly relate to them. In five minutes, Uttam singh's kaku became my kaku as well.

The theme of this post is Kaku. There is nothing unique or special about Kaku. He is just another man from the hilly town. But i was meeting someone senior from the hills for the first time. For an orthodox south Indian, meeting a himachali in an obscure village in the foothills of Himalayas is a very enriching experience. Other than belonging to the same country and worshipping the same god (Rama and Shiva), all our practices are different. 

Kaku from Chandpur
Kaku is 76 years old.  A very orthodox man who spends two hours in the morning worshipping. He believes in the ghosts and the like of the hills. As he confessed at one point of time, he was alcoholic and use to drink all night. He says , now his health and god does not permit him to consume alcohol.

By profession even today, he is a chaukidhaar (Watch man). He stays few hundred meters from his work place across the stream.   He is up by 5:00 AM and takes bath in the chilling water of the stream (It was 7 degrees when i went there and snowfall had started in the upper hills.) The temperature drops further by January and February . But kaku insists that he would have bath in the stream. 

Kaku is also a good singer. He sits by the fire every evening singing the folklore and the local bhajans. He enjoys his beedi too sitting by the fire. 

We had to literally cajole kaku to sing a Himachali (Kangri) Bhajan for us. After a lot of insistence, kaku did sing something for us. It was a pleasure to listen to him sitting by the fire in the chilling evening. Kaku was also graceful to throw some light on the meaning of the song. 

There are many many such people scattered in the vast plains and hills of this country quietly singing their way in life. They are contented , untouched by the pollution and corruption in the country. 

                     Kaku Singing his Bhajan                    

Wednesday, October 29, 2014

Rooftop Solar Power Plant

From the time i took a pledge to be a little green in my living, i wanted to run my house on solar power. I am a great believer that Solar, wind and small hydro power are really a sustainable solution for the energy crisis that we are facing. 

Solar power, however is an expensive technology and does not yield economic returns in the short to medium term. But i still feel its affordable for the middle class. It is because of subsidized grid power that solar power has not gained popularity and its a general feeling that solar power technology does not break even at all. Also the environmental costs of producing conventional power (Coal, Large scale hydro) is never captured in our calculations. 
The idea of this post is not to argue for an economic case for solar but its about my efforts to put up a solar power plant on my rooftop. We designed and installed the rooftop power plant in our house in March 2014. 

Below i try to put down my experience in designing and installing the power plant. 

Energy Requirement:

The First step in designing the system is to carefully examine one's Power requirement.
The power you need is the instantaneous intensity of electricity required to power the appliances you use; this is measured in kilowatts. The more appliances that are used at the same time, the more power required. Energy is a measure of the length of time you have used a given amount of power. It depends on the power required by the appliances and on how long and how often you use them. Electrical energy is measured in kilowatt hours (Kwh). You need to know the electrical power and energy requirement for lighting, heating, cooking and other uses for your home How large a system do you really require is a function of Power requirements which is not very easy to measure .

To estimate how much electricity you need:

• List all your electrical appliances and lights and note when and how long they are used.
• Note the power that each appliance consumes. An appliance’s power rating is usually written on the back of the appliance and is measured in watts or kilowatts. 
• Record the number of hours each appliance is used in a typical day.
• For each appliance, multiply the power rating in watts by the number of hours used each day to obtain the number of watt hours (or kWh) that the appliance uses per day. 
• Energy-use patterns change with the seasons (e.g., lighting is generally used more in monsoon/winter).
• Add up the watt hours for all your appliances. This total is an estimate of your electrical energy consumption per day. Then you can calculate how much energy you would need per month.

The above exercise was done for the lighting loads of my house (Excluding heaters, refrigerators, microwave oven and iron). 

The table below are the results

 Sl No 
Power rating 
of Hrs 
 Watt Hours   Consumed         (Wh) 
         Units             (Kwh) 
   1.00  Fan 1 (Office)           70.00      8.00          560.00       0.56000
   2.00  Fan 2 (Hall)           80.00      4.00          320.00       0.32000
   3.00  Fan 3 (Room)           70.00      7.00          490.00       0.49000
   4.00  LED 1 (Office)            7.00      5.00            35.00       0.03500
   5.00  LED  2 (hall)           10.00      4.00            40.00       0.04000
   6.00  CFL 1 (room)           14.00      2.00            28.00       0.02800
   7.00  CFL 2 (kitchen)           14.00      2.00            28.00       0.02800
   8.00  CFL 3 (utility)            8.00      0.50              4.00       0.00400
   9.00  CFL 4 (Bathroom)            5.00      0.25              1.25       0.00125
 10.00  CFL 5 (Toilet 1)            5.00      0.50              2.50       0.00250
 11.00  CFL 6 (Toilet 2)            5.00      0.25              1.25       0.00125
 12.00  CFL 7 (Toilet 3)            5.00      0.25              1.25       0.00125
 13.00  Computer 1            90.00      9.00          810.00       0.81000
 14.00  Computer 2            90.00      6.00          540.00       0.54000
 15.00  Television          100.00      6.00          600.00       0.60000
 16.00  Set top box            5.00    10.00            50.00       0.05000
 17.00  Misc        0.25000
 Total      3,511.25          3.76

So i need to generate about 3.8 Units of power per day to power all my non inductive loads. 

The next step is to choose the type of system. That is to design an optimum configuration where the solar power, the battery power (Charged from solar and grid) and the grid power is used in the most efficient manner. Broadly there are three configurations. 

1. Off Grid System: Off Grid or stand-alone system refers to being independent of the state grid. The design would support all the loads and sufficient back up can be provided to cater to the power needs worst conditions.
One can go off-grid for low intensity loads. In other words, all equipments having a power rating lesser than 500W can be taken off grid. 

2. Grid Tied System : In grid tied systems, the system is interfaced to the state power grid. Here, Solar takes the first priority to run the loads. The excess power, if generated will charge the battery bank. The excess from the battery bank is fed into the state power grid. Grid tied system can be configured without battery bank also.
In case there is deficit of solar power, the differential power is drawn from the state power grid.
In case of grid tied system, a meter to record the net power (Net metering) will be installed.
3. Hybrid System or Grid interactive system: Hybrid system is a smart system involving, solar, grid , battery bank. A DG can also be added if required.  Here, Solar takes the first priority to run the loads. Excess power generated will charge the battery bank. During night battery will support the loads till a safe battery voltage. System will switch over to grid automatically below battery safe voltage. (If GRID is not available and battery has been discharged, PCU can command DG to start and supply power to the loads till Grid or solar is restored).
Hybrid systems can also be configured as grid interactive systems where only solar and grid are present. Here, the first priority is given to solar. Excess power generated will charge the battery bank. During night battery will support the loads, till a safe battery voltage. System will switch over to grid automatically below battery safe voltage. This would extend the battery life and provide seamless power supply. There will be no power exported to grid. 
In view of economy and ease of use, the grid interactive system is the best. One can slightly under design the system also if budget is a constraint. 
In my house, i decided to go in for a grid interactive system. The system consists of 
1. Solar Panels
2. Battery Bank
3. PCU or Power conditioning unit. 
In bangalore weather conditions, one kilowatt peak (KWp) will generate about 2.5 units of power per day on an average bright day. So if my requirement is 3.8 units per day, i would need 1.52 KWp. 
So i would need a power conditioning unit (PCU or inverter) that can support 1.6 KW. However, it is prudent to go for slightly higher PCU to account for accidental higher loads (or in event of guests at home).
The battery bank is designed to cater to maximum night loads. Also many PCUs needs a basic minimum voltage to even start. As such for a 2KW system that i decided to put, i had to connect 4 batteries of 12 V each in series to give 48V. 
So my final configuration was

1. 6 modules of 230Wp solar panels (total of 1380Wp)
2. 4 numbers of 100Ah, 12 V deep discharge batteries in series. 
3. 2KW PCU (i decided to go with a PCU with transformer).

The mounting structure proved to be the most difficult part of the installation. There were two riding considerations for mounting structure. 
1. The structure has to be non penetrative. That is we did not want to drill the roof to fix the structure. 
2. We wanted to keep the cost to care minimum without compromising on quality and safety.  
The mounting structure was designed in view of economy and wind loads. The design we arrived was a very simple "Z" section of 3mm thickness, web length of 6 inches and flange length of 9 inches with oblong slots. We got the same fabricated with powder coating. 6 such sections were fixed to each panel.  
The panels were just anchored to the mounting angles with nuts and bolts. The panels with angles were placed on the roof. A rubber pad was placed between the angle and the RCC roof to minimize friction caused by wind. A simple clay brick counter weight was placed for additional safety. 
For the DC wiring, we got double sheathed DC cables specifically designed for solar purposes. We got the right switches and the wires. 
After all the electrical and structural design, we had aesthetics to care of . Thanks to power  tools from Bosch we did and re-did the wiring (DC and AC) thrice before we were happy with the aesthetics. It took full three days for three people for installation. All in all it was a terrific time designing and installing the system. (A short video is at the end of the post). 

The final phase of the work was to check the system and measure the efficiency. So after about two weeks of installation, we measured the key parameters. A graph of array current and array voltage against time was prepared to study the system. Below are the results. 

Time Array voltage
Array Current 
Total Power Produced (W)  O/P
O/P Voltage (V) Battery Current (A) Battery Voltage (V)
09:00:00   54 2.9        156.600  10 231 1.6 51
09:30:00  53 3.2        169.600   4 231 0.1 54
10:00:00  54 5.3        286.200  6 231 0.5 51
10:30:00  59 13.8        814.200  9 231 7.3 56
11:00:00  59 12.8         755.200  5 231 7.9 57
11:30:00  59 12.2        719.800  6 231 7.3 56
12:00:00  60 12.6        756.000  5 231 2.1 56
12:30:00  61 13.9        847.900  7 231 9.5 58
13:00:00  61 15.6        951.600  8 231 2.8 58
13:30:00  65 6.6        429.000  8 231 0.9 54
14:00:00  62 4.9        303.800  6 231 2 54
14:30:00  63 6.5        409.500  5 231 3 54
15:00:00  54 3.1        167.400  5 231 1 52
15:30:00  63 5.7        359.100  6 231 2.3 54
16:00:00  62 4.7        291.400  5 231 1.7 54
16:30:00  54 2.1        113.400  6 231 1.1 52
17:00:00  53 2.1        111.300  4 231 0.7 51

Key metrics from the above table are.


 Max instantaneous power produced          951.60  W 
 Total hours of power production              4.02  Hours 
 Max Power produced per panel (W)          158.60  W 
 Total units of power produced              3.82  Kwh 
 Total power produced      3,821.00  W 
 Number of hours of power production              7.00  Hours 
 Power consumed by charger          100.00  W 
 Power lost during charging          700.00  W 
 Power available at the battery end      3,121.00  W 
 Battery to inversion efficiency            70.00  % 
Power available at distribution box      2,184.70  W 

Maximum units produced                                       2.67       Kwh
 (after all losses)                       
The power production was actually less than expected. There are two reasons for that.
1. The day was not that bright. We had few spells of cloud cover. 
2. There was a tree shadow on one of the panels after 2 PM. Since the modules were made of polycrystalline cells, practically the whole panel will not function if there is shadow on any portion of the panel. 

However for a 1.38Kwp power plant we can easily expect about 3 units of power on a moderately bright day. 

Since it is a grid interactive system, the balance power requirement for the day was met by state utility grid power. 

         Installation Video