The 2’s

The world is balanced. Often we hear and listen to this sayings even we read many where in books as well in the holy books from heaven too. The world is balanced with what? Once I asked to wise man. His reply made me more curious to know the answer. Wiseman replied me,” you are not enough matured to know the answer; kid”. These are among those sort of saying that makes a burn in the skin and heart as well. I stared a long towards him and suddenly get the catches. Yes there were not a single catch there were several catches I could realize. One of the catch was “The truth will be burning”. 2nd catch was; wise man thinks that I have not that much patience to learn about it. The 3rd catch was I have to work by my own to search for the truth. Another catch was I have to take pressure and load when the truth will be unveiled. As I knew wise man, I could get all those catches he threw. From the very beginning of civilization; people learnt to think first. They use to seat looking at the sky for whole day and night by opening their mouth. Their job was to think about the logic of the anti logic those used to be practiced in our society. Such as; people use to think that world is flat and this thought was a belief as deep as the beliefs of religion in some communities. This was a normal and logical thought of those times. The thinker then gave their logic that,” The world is not flat, it is round”. Normally people use to get anxious of losing their god and they became angry on the thinker who said the world is round. These sayings became anti logic and the thinker was treated as mad and behaved very brutally some times. These people were the 1st generation people of starting of civilization. They were great philosophers and we may know some names too. Alas they were the blessed people of nature. It’s another rule it has been discovered since the starting of civilization that these blessed people are treated very brutally yet of their contribution towards the prosperity in the history of the world. This was the reason people had a thought that nature doesn’t unveil the truth of it’s secrete. This is a proven logic. This is the reason the blessed people were behaved very brutally in the society in the most of the times. This became the father of the demon for the reason. This is one logic. At the same time nature gave rewards who unveil the natural truth after a particular time period. They became the stars of the time. They had the endless life. They became the honorable. They rewarded same as a good son get received what he demanded after doing the good job. They became the blessed people as the son of a good mother. So we can see the nature wants to unveil it’s secrete. For the 2nd generation or the generation of prophets and religious persons we may see the same result. These prophets, blessed and religious people were behaved the same also. First the pain then the gain. The 3rd generation also did the same. After end of coming all prophets and religious people; the scientist, novelist, painter, writers, players are coming as the blessed people of the mankind. But they had to do this too. It PAIN & GAIN. This is very interesting logic nature had set up for us. This is the rule we call it balance. Some people will say it hypothetical. Some will say necessity. The experienced says “NO pain , No gain” My question is why? Because pain give birth of angel and gain give birth of demon. Who are the mother and father of next demon and angel. Did we ever think that this is the thing that gives birth of racism, harms the communal harmony? Written by, Sahriar Ahamed Cell: +01834529357 sahriarahamed@yahoo.com Mirpur-1, Dhaka, Bangladesh

Alternative and renewable energy by power of WIND

Hybrid PV-Wind systems There are some places where wind speeds are often low in periods when the sun resources are at their best. On the other hand, the wind is often stronger in seasons when there are less sun resources. That can make solar PV-wind hybrid solutions an alternative to consider. Even during the same day, in many regions worldwide or in some periods of the year, there are different and opposite wind and solar resource patterns. And those different patterns can make the hybrid systems the best option for electricity production. Hybrid PV-Wind system is the combination of PV and wind turbine for the generation of electricity. Picture: Hybrid PV-Wind systems Grid-connected PV systems DC power generated by PV is converted into AC and is supplied to the national grid. Energy storage is not necessary in this case. On sunny days, the solar generator provides power, e.g., for the electrical appliances in the house. Excess energy is supplied to the national grid. During the night and overcast days, the house draws its power from the grid. In this way, the electricity grid can be regarded as a large “storage unit”. In the case of a favorable rate-based tariff for PV electricity, as in force in some countries, it is more advantageous to feed all solar electricity into the grid. Grid-connected PV systems can be subdivided into two kinds: Decentralized Grid-connected PV systems: Decentralized Grid-connected PV systems have mostly a small power range and are installed on the roof-top of buildings (roof-top or flat-roof installation) or integrated into building facades. For example, in Germany around 80% of the more than 50,000 existing grid-connected PV systems are installed either on the roof-top of a building or integrated into a building façade. The benefit of the installation of a PV system into or onto a building is that no separate area for the solar generator is needed. Centralized Grid-connected PV systems: Central Grid-connected PV systems have an installed power up to MW range. With such central photovoltaic power stations it is possible to feed directly into the medium or high voltage grid. Mostly central photovoltaic power stations are set on unused land, but in some cases an installation on buildings, mostly on the flat roof of greater buildings, is also possible. Single phase less than or equal to 25kW. Three phase less than or equal to 300kW. Grid-connected PV System can also be classified according to size : Small – Power from 1 to 10 kWp. Typical applications are: rooftops of private houses, school buildings, car parks etc. Medium size – Power from 10 kWp to some hundred of kWp. These kind of systems can be found in what are called building integrated PV (BIPV) systems, in roofs or facades. They may operate at higher voltages than smaller systems. Large size – Power from 500 kWp to MWp range, centralized systems. Picture: Grid-connected PV Systems (a) Decentralized (b) Centralized These systems are normally operated by electric companies. In general a grid-connected PV system consists of the following two main components: 1) PV Module; 2) Inverter The complete system consists of a support structure, cabling, and other conventional components. Besides the modules, the most important part of a system is the inverter. Inverters for Grid-connected PV power systems can be subdivided into the following classes; a) Line-commutated grid-connected inverter; b)Self-commutated grid-connected inverter. Line-commutated grid-connected inverter: In this inverter the AC output generated is dependent on the utility interconnection. The system will not work if the utility interconnection is lacking (e.g. during grid black-out). This system is able to feed the grid only. Self-commutated grid-connected inverter: In self-commutated inverter, the AC output generated is independent of any utility interconnection. Thus this system can operate in the stand-alone mode. Picture: Line-commutated Grid-connected PV power system Written by: Sahriar Ahamed Mirpur1, Dhaka, Bangladesh

Wise Man

Wise man It was 4:15 PM when he woke up. It was a nap after lunch. Usually he uses to take this rest at his home. His house is only a ten minutes bus journey distance from office and most of the day his lunch time exceeds least by half an hour. His reporting boss doesn’t mind of this luxury of him and why not? He is the key person to run this operation and also the solution of all problems of official job. From peon to the in-charge operation every body has to call him at least thrice a day to solve their problems. But today it’s different. He took the nap after lunch on a chair out side of the office of company chairman room. Air condition system is on in the waiting room and a fan was slowly moving round over head from ceiling and creating some cool air. The off white color on the wall is making a sophisticated feeling in mind and beautiful paintings canvas are hanging on wall and those are mostly blue colored canvas. Total interior is driving his mentality towards a bit relaxing mood. There is no doubt the interior decorator is a genius. “Is this feeling happen to all other person who come and wait here or it’s only him who is influencing? His girlfriend Lopa has an allergy to blue color. If she would come here for any purpose definitely she wouldn’t want to stay for long. All peoples are different.” He thought. It had passed more than two hours seating on the same chair. He is waiting for a call from the company chairman. He was supposed to get the job termination letter today. May be the company chairman is re-thinking about termination-the extreme most decision. He is taking his time. Until the chairman sir finalizes decision; he had to wait out side of the office room. He doesn’t mind to wait either sitting or standing any where. Al-though it’s a general human tendency that they can’t wait; every body needs the desired things right at that moment those who negotiate their maximum considerable period is also the least time that is as soon as possible. Once mind is made up they try to do hurriedly. Waiting is the most undesired things to them. They never keep it in mind the error occurs from hurriedly start up work. Wise man always used to tell “Him be calm and steady. Speed and hurry always forces you to make error. Many civilizations had been destroyed because they were impatient”. Wise man is very interesting character ever he met. About any thing, stories, places and many more occasion advise he has. Al-though he doesn’t much care about advices but the pleasure with wise man is that if they get suitable time they had gone to river side for fishing. It was not far from their house. Their chosen place was the grassy bush at the southern side of the river. He can wait for any one or any thing for long. He finds fun in it because while waiting for any thing, it takes 2 or 3 minutes to fall sleepy and with in 5 to 10 minutes he falls in deep sleep. Very strange dreams he dreams in the sleep. Most of the times he dreams that he is flying on sky or going home flying or any thing he is doing; is doing it by flying. Back to some days ago he got stuck with the electricity cables and internet cable beside the road pool while he was flying. Suddenly he woke up and discovered him seating in the office bus returning home, ”Thank god it was a dream” he taught. The sleeping habit causes no problem after he started his professional life. Previously he had fallen problems in many occasions due to this habit.. When he first time came to Dhaka; he stayed with his cousin. One evening he went to near by park for a walk. The park was surrounded with trees, fields are covered by grass and with a small lake at the centre of the park made the scenario more attractive; a big area with comfortable breeze and after two or three hours walking he got tired and sat on a bench of the park to take rest and without making a miracle he fall in sleep after a while. A police man woke him up from sleep and told him that this is not an area to sleep at night. Night! The policeman surprised him. Rubbing his eyes with both hands he stood up and shocked to discover that some one took his shirt, trouser and shoes while he was sleeping. He was standing wearing only a underwear in front of the police man. Sudden shock made him dumb. First he held two hands crossed together and tried to hide underwear as much as possible. Then he shook his head for few times and without saying a word he just walked away from there itching his head with left hand. First thought came in his mind “Owo! What a save had happened with me. Nearly my prestige had gone away if the underwear was stolen too. Thank God for not falling me like a situation of shame” He found an old news paper on the dustbin beside the main gate of park. He took it and rapped his body with it as much as possible. Till to reach home he became careless of the passersby’s look with full with strange and interesting expression. Those expressions of eyes are unforgettable. He fells like laugh when ever the memory comes in his mind; but where he is sitting now a laugh may influence the situation in to another direction that would make the scene long and panic. He wants to come the conclusion quickly it’s getting on nerve. It doesn’t mater what ever is going to happen. He had his mental satisfaction as he was given the job; so does he did it with the perfection. It doesn’t matter they did not value it. Wise man use to say” Remember one thing, no work goes in vain. If it’s not valued now it’ll be valued later on. If it’s valued not here, it will be valued some where else”. It had passed only 14th months since he is in the job as the probationary officer in the department of operation. In this fourteen months he realize that he understood the business, official procedures, accounts, management, employees issue and solution more than his bosses are. Even his bosses are cautious of that too and when ever he comes for a job usually they become careful. He usually did not show any pride or negative behavior with any one at office. Mostly he kept silent and felt uncomfortable inside him. It was a situation those are very torturing in mind because his common sense always made him to be careful of it “Nobody will take it positively. The man knows more than me; is a smarter guy in any corporate environment. So there is always a chance to become out smart in-front of others and there is another problem that it’s him the most wanted in every department.” Why any one should take a chance to become an idiot by a new comer. Rather avoiding him is a good policy and if get a chance talk some negative comment or complaint to the management. Actually he was a threat to all the in-charges of all departments. As a result slowly he was turning in to a villain to the chairman of the company. But there is another unwritten law is there that the company chairman doesn’t want to fire any employee unless he did any major crime. So he was having a chance to continue his job. With it another fact was continuing with it and that is any fault he was the man to blame; complaint after complaint got over flow which made irritate chairman sir by the thirteenth month. In the fourteenth month management had no other way to take decision against him. He knew he had to face the embarrassment sooner or later. He used to oil and praise every body to make the interpersonal relation well with whom he came in to interaction in the company. As back-up he kept his reporting boss in his hand. It didn’t work at the required time. Thing was that his department in-charge was jealous of him. His department in-charge was a talented person too. He used to give the appointment to only his relatives and friends and do not tolerate the management people who have came through proper procedure under HR job policy of company. So the situation was there that among the employees most are the department in-charges’ friends and relatives. So in the department he could not able to do that is the right thing to do. Most of the time any meeting and decision He was kept out of scene. Yet the necessary doings he had done by his reporting boss. This was the reason his reporting boss was very pleased to him. His reporting boss had to consult with him and discuss with in-charge in the meeting about any issue. This was the whole corporate environment going on and it took fourteen months to make the situation like this. Every one had shown their own credit to company chairman; incase of any problem he who is the person identified as responsible. The in-charges didn’t forget to show small problem in to very big and as a new comer he had no way to make clarify of him self. With it the department in-charge immediately shouted up on him and through an email to the company chair man whenever he got any chance. And call for a board meeting that he has no idea of corporate environment. This is the reason he knew that this situation is coming and it’s coming surely. He was mentally prepared for it. To say it in proper way that he was made as to face this situation so does he felt nothing inside him self no tension or fear or any thing. Mokim the PS to company chairman came and take a seat beside him and asked,” Are you tensed” He replied “No”. Mokim got surprised with the reply he was not expecting this type of answer. He was expecting some panic, pathetic type of expression and foul comment against company’s management decision from him. Instead of that he remains calm, quite and non reactive with out any expression. Mokim did not take it positively. If the situation did not give him pain and sorrow; then Mokim thinks it’s his personal unsuccessfulness. Mokim wants him to suffer so asked again, “What will you do after you left the job? You have a family to maintain. You stay in rented house; you will be facing a very big problem. You should think for the expenditure in coming months and over all in the current situation of country’s economy it will not be easy to find another job so soon. A lot of pressure and burdens are coming on you” Observing his face with keen eyes Mokim tried to lead him the direction what he was expected. Just staring blank at Mokim he said,”Can I have a cup of tea please?”. “Strange man” thought Mokim “Dangerous and complicated as well. This type of man can do impossible. He is getting terminated from his job after a while and with out any tension he is asking for tea! “This man is insane. If he stays at this office, personally a lot of harm may happen to my self and growth of my backward financial development and company may get success and all the employees will get the benefit. I should not allow to happen this. It’s only me who will grow and other will be my servant.”. Mokim took his decision. As PS to the chairman sir Mokim has the most interaction with him in any working day, thus is possible for Mokim to divert chairman sir and influence him to take wrong decision. Mokim gave a side look to him; the way he was seating and expression of his eyes was telling that he knows many things. Mokim knows people very well; his service year is no less than 20 years. This man seating and waiting for termination letter is a fearfully dangerous man. A cold blood wave of fear feeling went through his backbone. Suddenly the PABX rang and Mr. Mokim the PS to chairman hurried into chairman’s room. After 15 minutes he came out side and said him “Go inside chairman sir is waiting for you”. He stood up slowly and knocked twice at the door and enters in to the room. Company chairman was seating in his chair with his huge belly wearing a blue color shirt with matching tie. He ate up the laugh in side him because chairman sir was looking like a clown wearing this out fit. Only a long blue hat will make him the joker of a circus. As per the situation demanded this room is well decorated with the air-conditioned the digital monitor is showing at 12 degree. Galaxy Samsung note pad and mobile 3g were occupying spaces on table with apple slim lap top red color. He always hankers after this slim latest model laptop. “How much it costs “he thought; “Current market price must be valued equal to his 2years salary of him”. In Bangladesh as the 3rd world country the financial differences are very abnormal. Those who are rich have lots of money even they have no idea of their wealth and those are poor they just don’t have anything. They live on open road highways, foot- path, rail way station and bus station. Most of them are beggars by profession. They beg by day at the road, bus station, and train station areas. Usually they carry a plate that is obsolete and having tap on its body and usually they were torn and dirty clothes. Their investment are all these and peculiar thing is that the foreigners come to visit Bangladesh; they take pictures of those beggars. He saw many times foreigners are taking picture of these beggars in street. The beggar is giving pose in front of camera same as a model of TV show. But pity is that when they return their country they publish the photograph and think that what a great work had been done. Ever they thought the other citizens of their country? They see these pictures and assume Bangladesh as land of beggar. Thus our respected citizens get offended when they go for any tour or visit. Because they did not have their respect those are getting from own country. Being poor ether they get sympathy or negligence from the foreigner. These respectable are really felt poor being experienced poor behavior from the foreigners. What more they can expect as those foreigners are learnt from photographs and got the idea that Bangladesh is a land of beggars. Among some others the foreigners really try to avoid them which are hampering their prestige too. Really the Bangladeshi visitors are very poor in-front of the foreigners. Other than these beggars some of them are maintaining life by picking pocket and doing small criminal activities. In between rich and poor there is another group of people, this community is known as the middle class community. They don’t have much wealth. Their earning level is hand to mouth livings and by the end of life they can able to have a little savings and left a struggling life for their children. This community is the major part of the total population of 15 hundred million population country. In this case of middle class and rich group the difference is also huge. Rich people are relay rich with wealth, money and vehicles and capable to use the latest technology around the world. Wealth less and middle class remains out of reach of latest technology. But when they have any up to dated technology in hand they feel very proud. They dream to have the modern and latest up-dated technology and life; same as him. Chairman Sir was watching some thing on the apple slim laptop screen. He pulls down the monitor and said looking at him, “As you have heard earlier from Mr. Mokim, your academic back ground, experiences and the job requirements are not matching. So we are no longer keeping you with us”. said chairman sir with his husky voice and stop for a while. Suddenly the chairman realized that he is standing yet. Then the chairman asked him “please be seated”. Sir maintained some curtsey. He took a chair and sit on it. He was staring at the chairman’s face. He saw respect as well some irritation in his eyes. It’s natural because the fact is not very pleasant to enjoy. Then chairman asked him again”Did you find another job? I think Mr. Mokim told you to find another job earlier”. “No” he replied “I was asking for a month or two so that I can find out another job”. “Well I am paying you next month salary. You will submit your resignation and from today you are off from your job. Did you get me?” said chairman. He was looking blank to the chairman silently. Its not that he was tattling or trying panic the situation. “Understood?” asked chairman again. “OK sir” calmly he replied. Chairman press the intercom and ordered Mokim to come in. Mokim took only 30 seconds to enter the room. “Receive a resignation letter from him. Ask the accounts to prepare a cheque of his one month salary and give him. Take his signature of receiving the amount”. The chairman ordered to Mokim. “ Well best of luck. Wish you all the best” said him and concentrated at his lap top again. Mokim and he stood up together and get out of the room. He was following Mokim. Mokim was walking fast through the corridor he wanted the job done as soon as possible. Mokim’s figure is not that good. He is a fat man huge amount of fat is trying to coming through the sky color full sleeve shirt he wore. The starched fat are moving as if some one throw a stone in the middle of pond and slow waves are coming one after another to the bank with each step he was walking. It was very funny looking way he hide the laugh. He was not serious about the incidences that had happen a while ago. Al though he pretended very upset and kept his face very sad looking. He knew what had happened was not going to make any harm to him actually company had cut its own root like an over smart funny guy. But thing was that he could not help them not to do that. He is very confident that what he had done; done for the good of major. He also knew that the Chairman thinks him nothing but an over paid stupid. No one could ever realize the inside tunings among employees, the basic set and lay man in the activities. Truth was that he worked as back bone of the company and intentionally or un-intentionally they broke it a while ago. He was confident up-on what he learnt from his job and thinking to get another one. The chairman and all other will get understand it sooner or later. After getting the payment cheque and release letter he came down from the office on the road. Take a look behind the office and a long breath fall un-intentionally. Suddenly the power generator had a blast and entire building electricity gone off. He saw the security guard running towards the generator room and their walkie-talkie became alive. Different machine voices and commands are coming from to it. He felt a little uncomfortable and look above. The sky was very clear and lots of star was shining all of a sudden he discovered that today stars are more than usual. Usually after dinner he goes to roof and lay on the water tank smokes so the sky is very well known to him. Usually he talks laying on the water tank with him self. Most of the time it is related with the nature. He ask question and give answer of the question inside him. Such as, “Why I am here?’ answer comes in mind “Because nature needs you”. Question comes” for what nature needs me?” Answer comes in mind “You will see it by your self”. Then again the question come, ”Am I important to nature” Answer comes even an insect is very important” This type of soly-lookee he likes most. His most interest is in nature and supernatural things. Some how he is occupied with a thought that nature has a plan; it is making thing accordingly and destroying as required. It’s more than interesting. If the job is done by any thing or any one; nature eliminates them or him. Either they die or destroyed by natural disaster. “Where did you came from?” a clear and loud voice made his mind come to practical world. A long figured man wearing a jeans pant and white t-shirt was looking with question in his eye. Probably he did not take shower and shave today. His out fit made him looking dirty. It’s an annoying question to answer. It’s none of his business. But he felt a bit of fun inside him. Looking direct to the man’s eyes he indicated his office building and said “From above”. The dirty looking man asked again,”do you live above?” in the same way indicating the office building as him. “No, it’s God who live on above” replied he the dirty man said “I know God lives above”. He replied “IF you know then what and why you are asking to me?” and hurriedly walk away from there to bus stop. He has to catch the bus returning home it’s getting late. It was 7PM when he reached to bus station. A large number of people were there standing in a line waiting for bus. He bought a ticket from the counter and takes his place behind the queue. He was thinking about the accident that had happened after he left the office building. Sudden short-circuit made the power failure. Is it a coincidences or there is any thing that the nature indicated? If it does; then to whom the indication was? Only to him or to all the people of the company? If it’s toward all people of the company then the massage went in vain isn’t it? No body is going to understand it. He got it as a signal of nature that there must be going some thing wrong with the company soon. If any thing will go wrong; some how an intention works in side him. He feels pressure inside him. His intension makes him tensed. After a while natural intelligence tells him;” Does it make any differences? What ever the thing is going to happen that will happen. The most dangerous and alarming is the survival is the issue. If nature needs me I’ll survive in any way if nature doesn’t; no way can I escape from the danger. But natural intelligence can help quite a little bit even after that the pressure is up on to him. The feeling of tension keeps it on. This is very mystery although the main characteristic of nature is such. Some how he observed that his normal blood pressure is always very high. Some days ago he went to doctor to see weather he’ll required medicine or not due to fever that he is suffering. After all check up doctor told him it’s not very serious fever. All though he knew still he asked doctor to check up his blood pressure. Doctor checks it and got shocked and told him “you certainly can not sit here and talk with me like normal person” He asked doctor “why?” Doctor told him that “your blood pressure is abnormally very high and a normal person would faint at this blood pressure. You should get admit you’re self in hospital.” He smiled and told “Don’t worry doctor “ while he leaving the chamber walking. He felt the strange look in eyes of doctor on the back of him. He did not felt any thing because he knew some thing wrong is going to happen that’s the reason his blood pressure is very high. This is the reason he loves nature and naturalistic things and happening of nature. May be nature loves him too due to the same reason? If nature loves any one does he or she gets any privilege from nature? Or if reversely it could be nature hates any one, what does it do with him or her or it? Interesting, it is very interesting. There are some example with the chosen person who had the leader ship and gift of nature with them to lead the humanity up to certain direction. They had shown how to practice the man kind, peace, worship and sacrifice for the people. They had shown what happen to the person who had cross the limit and brought down the humanity and mankind. Why nature is doing this? What is the reason behind all of these? He knows sooner or later people will know all about nature. What will happen then? Because people needs problem to pass the time through resolving the problems; if the problem is gone then there will be no longer any reason left for human. That would be a very critical situation. The queue was long and bus is delaying. Some people started shouting for the cause of late, the bus company man was trying to tackle the situation by making cell phone call to the bus authority. There was three more bus counter side by side. A bus from another route came, took the waiting passengers and left in font of them the engine was roaring badly and the exhausted pipe throw black smoke. Every one put some thing on their nose. The carbon monoxide is harming people very much. But general people are not beware of it. The ozone layer is harming and harmful rays are coming in the world from those whole. Some times he thinks that there will be a tunnel from the Earth to the Moon . The mouth of tunnel will be 100 meter above earth. There will be a machine whose job is to receive carbon mono-oxide from the earth surface and through the tunnel this carbon monoxide will send to the moon.. The tunnel moth will be prepared in such way that some kind of machine whose job is deducting carbon and oxygen as separate molecules. Soon there will be two gases which are useful to survive the life in the moon. There might be more gas elements. He tried to remember the name of those. Another one is Hydrogen. He could not remember more. “I have to read the book written on the environment of the Moon” he thought. His bus came after fifteen more minutes. He got up on the bus but could not able to get a seat. So he stood with the ceiling handle. There are some cute girls were standing holding books in their hand. The evening session of any university may get closed. Suddenly the bus driver presses the break very hard. May be he used Hydraulic break. Every one of the bus got fall from their places. One of the girls falls on the floor and got hurt in her hand seriously. A man holds her another hand said “Please be seated on my seat.” But unfortunately he could not able to finish his word. The girl slapped hard on his face and cried out “How dare you touch me”. The person had nothing left to say. He was just standing holding the ceiling handle of bus rubbing his jaw where he got the slap. Interesting is that no body said any thing about it. Again the bus started to move on. Some loud voice came over pointing the driver “Hey! Driver be care full” Some voice said “Go slow” etc. He thought what a scene to enjoy the man showed sympathy to the girl but the girl did not tolerate it. He came to a decision girls are very sensitive of their body. They keep it reserve for their special person. Females are very interesting and strange in behavior. When he arrived home it was late in the night. It’s about 2 AM. He opened the door and just went to bed without any change. He was the nearest bar up to this night. He was so drunk that even move any further. He saw his aunty who was married to his uncle who was 2nd son of his grandfather came and give a kiss on his fore head and said good bye and take care and suddenly she walked away in passage which is full of light and she diapered in the light and he heavy light fall on his eyes that he had to close his eyes. Suddenly he wake up from sleep and saw it is already been morning and sun is up and sun rays are falling on his face. “OH! It’s a dream” he thought. After getting up from sleep it’s a habit of most of the people that what is the time it is? He follows the wall clock and saw it is already 10 AM. But he knew today there is no hurry. He was thinking does any body carefully observed about the common habit that after awaking up its common thing that every body wants to know what is the time now. Being in thought that “Human is very critical in behavior” after getting out refreshed from bath room. He had to take his break fast and read the local news paper of today. For that he had to come down stair where the small cafeteria named “KHANA- KHAJANA” is located. For last two years he has the common routine. Taking break fast from “KHANA- KHAJANA” and start for work. He came down to road and buy a news paper from news stand and get in to the cafeteria. In general he takes the table in the last corner to seat from where every thing is possible to see. Today he also did the same. The waiter put up two glasses of water on his table and went to bring his order as he knows what he eats as breakfast. He opened the local news paper and stunned to see the head lines. It’s written in bold letter “Huge fire knocked down X-man Group” two are dead and five are bunt to put off the fire. In detail its written on the paper that the fire began from the generator room and suddenly it blast and whole building caught fire so suddenly that the company chairman and his PS could not came out of the office They died of burning and their dead body will be buried today in the evening. The burnt 5 security guard are admitted in hospital and fighting with death. X-man Group is the company from where he was fired from his job last evening. Sudden shock made him lost. He come in to practical life from absence mind when the waiter asked him “Sir; Will you take tea today?” “Yes” said him. The waiter gone for the order and he became blank to think any thing. His mind started working again when his cell phone rang. It’s his mother’s call from another city where she lives with his father. His parents are very happily married couple. He picks up the phone and said “Hi mom!” His mother replied with heavy and emotional voice “Hi! Son; how are you?” He replied “I am fine mama. How are you?’ Suddenly his mother cried out over phone and told him “Son your Polly aunty died last night”. Poly aunty was the wife of his 2nd uncle. “Nature does nothing with out any reason. Every small things are not too small as we think. Nature has a plan and it ruled by it's self which we may see realize and feel. no one knows weather we should know it step by step or all at a time”. Wise man used to say him in many occasions

Soul can be formalized

What is life? Why we are on the Earth? What are we doing here? There are several concepts and theory already had been provided with by several blessed people from heaven but secrete remains in veil till now. Why? I asked to a known educated and wise man once. He told, “Secrete of life is remain in-veil because Almighty/creator wants to remain in to veil for time being. People has to grow and make prepare of them to know about creator. So he is exploring him self slowly, steadily and surely”. He continued, ”you can go through all the books from heaven. There it’s shown the life and soul is the part of Almighty/heaven”. So, secrete of soul is secretes of creator “What I could able to think at the time was: Nature is created by itself. Although nature known as lots of name in different time period of civilization but it has been remain as the Almighty/creator and fact is it ruled by its own rule. These rules are different in places, tribes, things etc. But those rules were from nature which had to be discovered by someone or thing or brain or by human. This was the reason for human to live life. May be they will continue these process till to the end of all rules to discover. This rules are to be discovered May be as human or may be in the way of some natural way. This is one more rule of nature. There is a rule of nature that every planet, stars as the sun, the moon is plotted in a manner on time. By the way it is plotted the time has got shrink a bit. After putting a heavy thing on a bed sheet or bed cover. It’s very difficult to explain this with thing or examples. Actually everything had to explain as the relative manner. The blessed man as Mr. Einstein who is very well known of his formula of E=MC2. Every natural thing is made with a formula. Such as water = H2O, carbon=C, carbon dioxide=CO2; (X+Y)=X2+Y2+2XY . Visible and non-visible. Wise man was telling, “Actually soul has the same formula as above. X=yz + cm3 or anything like this and I think if it is possible to discover the formula the secrete of creator that we know, will be discovered.” But what I think primary formula of human is H=B+S(H= human, B=Body, S=Soul). Now we may give the formula of body (B)= blood+Cells+Eyes+hair+nose+............+nail of foot. Now if you go further we may see the formula of Blood=White blood cell+Water+Red blood cell + Plasma......etc. In this way we can have the smallest item formula of human body separately and together also. In the same way we can have the formula of soul too. If wise man has any truth in his theory this may unveil the secrete of god almighty. The life containing in body or the creator of the life. Another thing would be possible, if a theory may go in speed of light or more than light. If that is possible the time travel is also possible. How the formula travels ? the answer of the question is, H2o can travel path if u through a glass of water with the power of ur hand. Here the water travel will not happen actually the formula travel will happen. So there r many ways to through the human body formula to through in the speed that is 100 times more than the light. If you can go at this speed you can travel time easily. So this is a simple thing. Wise man did not say any more things about it. But wise man told me not to use Allah, God, Vogban or any other name in place of creator, these names are specified and honorable. No one has right to dishonor these names. Sahriar Ahamed Dhaka, Bangladesh Cell: +01911063223

Business and Management is pure Science

Management, Marketing and Business development is known as Arts and as well as Science. If we go through the famous writers' books we may get this discussion in their books. But what I like to express that the model of business is changed completely. Now a days Business development is practicing in different organizations same as science. Here business is practiced as some instructions those are already set up to achieve the goal. Which is the definition of "Algorithm". A set of function to archive an object. Most interestingly these instructions are followed step by step. All these steps are followed in a order. 1st step 1st; 2nd step 2nd. If any one gives the 2nd step 1st he will finish with no result. This is the process which is known as Relational Database Management System (RDBMS). This is a process that is followed by IT engineers for a particular problems to solve; such as a software solution. So In this aspect it's proved that sales, marketing and management are pure science. Actually what I think from the very beginning of civilization, the generation of thinking people came 1st. Their job was thinking all the day looking at the sky by opening their mouth. And give the anti-logic of any illogical sayings and thought of society. They were known as the 1st generation of the world. After them the 2nd generation came with the thought that people should acquire knowledge and religion should be the part of our daily life as there are lots of things to learn from religion in other way from almighty/creator. These people were blessed and known as Prophets and other religious people. A time came and Almighty sent one blessed person who declare the end of the prophets and religious people. He was the greatest prophet Hazrat Md. (Sm.) After him the 3rd generation started to came. They were the scientist as Newton, Einstein, Tomas Alva edission etc. Writer as HG Wells, Alexender Damus etc. Painter, carpenter etc. All of them were the blessed persons. Which means the knowledge got more depth. It became the science of some knowledge. Such as IT, Physics,Chemistry, Maths etc. Now the goal of every arts subjects are to the science. I have a question does any one has any Idea who will be the 4th generation??? What will be their task???

Mr. Rafiqque –U- Daulla wearing western designed horse riding dress took a break on the left corner of the lawn in front of his palace. Behind him the artificial fountain and water stream was flowing with its flowing water sound through a marble made canal. He is not tired at this moment rather he wants to observe the surroundings particularly this part of lawn. This is the area where the Indian origin mango trees were planted. Sixty thousand of matured mango trees are there in this garden. Each year several metric tons of mango produced and thousands of people are employed and used to give their labor for collecting, selecting and packing all those and not a less than one hundred millions of taka comes from this mango garden. There is a narrow path way through the garden that ends in an open place where gardeners took care grasses to grow big and nutritious so that the thousands of cattle of Mr. Raffique-U-Daulla can full their stomach and become heavier meat full and fruitful by money also. . All total he has twenty similar gardens in his palace area. A five feet thick red brick wall is separating all those from the out side world. A thousands of employees, guards, care takers are involved to maintain the kingdom under the autocratic mind set of Mr Raffique .-U-Daulla. It is him and only him is the decision maker. Out side world laws and rule means nothing in side the five feet thick red brick wall. It’s a mystery to the out-sider what is happening in the palace. Only a few honorable and respected people get a chance to enter the palace only when they are invited. Mr. Rafique-U-Daulla sometimes used to go out side with his own force with him mostly for hunting of deer on the hills behind the forest that is once or twice in a year. Most of the villagers can see him during that occasion only. Other wise they are very busy to cultivate and farming their land. By blessing of almighty god what ever you saw the trees and fruits comes up with less effort. It was a reason why villagers were very happy and during all the year round they use to enjoy various festivals. The largest festival were occurred eighteen years ago.. When Mr. Shohail-U-Daulla came in the world as the only son and inheritor of Mr. Rafiqque-U-Daula. First feeling as a father touch him in heart he became greater than ever. As a result the villagers enjoyed good food, more meat with wine, singing and dancing after a heavy lunch or dinner. For seven days the village became a heaven and people could do what ever they want. But the security of Raffique –U-Dulla were there to observe weather there any chaos or not. So, nothing big mishap had happened. As a hole Mr. Rafique-U-Dula was a very strict, autocrat and peace loving ruler. People herby had a mental peace that they are under a very good ruler who gives the priority of peace .After birth of Shohail-U-Daulla his father made a plan for him. He decided that his son will be an educated man. He will achieve the highest degree from the university and after finishing the education he will apply the knowledge for greater service towards the man kind. Mr. Raffique-U-Daula thinks asset and money he already had enough. But for mankind there will be required special knowledge to improve the man kind and he wanted it from his bottom of heart.

How many lives does a life has?

One day I asked wise man,” where do people go after dead” . “There are several answer we may get”; replied wise man. I asked further what are they. He told about various point of view. Such as in the way of Islam, in the way of Judaism, Christianity etc. But at the end he told me that what ever the religion method is; there is a science theory also. And all the theory is of only by wise man. I got surprised to know that wise man can explain the after death world scientifically. I asked him “what is your theory”. He replied after death we go to the 4 dimension world. Before birth we were in 2 dimension world. And the life of 2nd dimension we were in 1st dimension world. I shook my head and got understanding mark. And said him “After death and life after death will be a six dimensional world isn’t it”. Wise man said “Positive and the thing will incur n”th time. Where the value of n= infinity”. I thought wise man got mad he needs a very good refreshment

Do not listen to him

While I was young, wise man use to say, “Son; make your fate by your own”. I always been very attentive to wise man as well careful too. But one thing confused me that; how do I can create my own fate while there is one god and he send us in the world and nothing can happen with out his permission. It was very confusing to me. I never thaught abut religion before that. I use to follow my parents and that my guardians tell me to do. I use to have my prayer regularly by going to mosque. At the age of sixteen, in sweet sweet sixteen some thing happened to me and I started experimenting of my luck and religion also. At the first step I just start deny of existence of religion and god and any luck of mine. I expressed it to my guardians and relatives and friends too. I knew it was safe because they will not atleast do any thing like the extremist Muslims; particularly the follower of Bin-Laden or Taleban of afganisthan. Love was the barricade of them. I observed that they are getting angry with my talkings and thaught. When ever I use to discuss about religion they became hrash with me. I took note it in my head. Then agian I start searching for the answer to my question of thaught. At the age of 18 I got a chance to visit India for doing my honors graduation in University of Delhi. I alone visited all the mosque of Delhi as well the temple of Delhi. Not only that I visited the famous places where pilgrims use to go for showing their devotaion towards God the almighty. I think I learn huge thing that people will get surprise when they know it. In one sentence I can say to all what I learnt there.I learnt that going any where in search of God is the most foolish job in this world and making experiment with life is always dangerous for bright future. Last of all my advice is to the young is, never listen to wise man if you meet him any where in any part of this world

Delaying to use the alternative and renewable energy? – Know detail about electricity storing system in a solar PV system

Earlier I have discussed on the necessity of using alternative clean and green energy such as solar photo voltaic (PV) panels for the resources of clean and green energy. Fossil fuel and other resources of power and electricity has limit and will be finished off with in near future. In early version I have discussed on PV panels and how they work. Not only in my early article; there are many readings and books are available to take knowledge on solar PV panels in market now a days. Many analyst and expert had discussed on solar PV panels in different magazine and news paper in recent time. There are some more components and equipments are using in a solar powered electric system. Those equipments are very important role to play in a solar powered system. I think people should know about these for their knowledge and usability. One important component in the PV panels is the storage system. It is required to have a storage system in a solar powered electricity generating system. The major role of this storage system is to store the electricity and release it when ever required for. As we know Electric power is generated only during day time by PV panels. But we need light at night. So some sort of storage systems has to be used with PV system. Although various types of batteries are available in the market, lead-Acid batteries are widely used in PV systems. Many of us may know that In 1859 French physicist Gaston Planté invented this rechargeable battery. Despite having a very low energy-to-weight ratio and a low energy-to-volume ratio, they have the ability to supply high surge current and relatively large power-to-weight ratio. These features, along with their low cost, make them attractive for use in motor vehicles and now in PV systems. Their huge Ampere-Hour capacity makes them suitable for PV system. The lead acid batteries may be divided in to some parts. Parts of a Lead-acid Battery: A battery consists of a number of cells and each cell of the battery consists of (1) positive and negative plates (2) separators (3) electrolyte and (4) the container. Different parts of a lead-acid battery are described below: (1) Plates. A plate consists of a lattice type of grid of cast antimonied lead alloy which is covered with active material. The grid not only serves as a support for the fragile active material but also conducts electric current. Grids for the positive and negative plates are often of the same design although negative- plate grids are made some¬what lighter. (2) Separators. These are thin sheets of a porous material placed between the positive and negative plates for preventing contact between them and thus avoiding internal short-circuiting of the battery. A separator must, however, be sufficiently porous to allow diffusion or circulation of electrolyte between the plates. These are made of especially-treated cedar wood, glass wool mat, micro porous rubber (mipor), micro porous plastics (plastipore, miplast) and perforated p.v.c. In addition to good porosity, a separator must possess high electrical resistance and mechanical strength. Separators: (1) and (2) Miplast type (3) Perforated type (3) Electrolyte. It is dilute sulphuric acid which fills the cell compartment to immerse the plates completely. Battery container Followings are the parts of the lead acid battery picture shown as parts separately. 1. Negative plate 2. Separator 3. Positive plate. 4. Positive group 5. Negative group 6. Negative group grooved support block 7. Lug 8. Plate group 9. Guard screen 10. Guard plate 11. Cell cover 12. Plug washer 13. Vent plug 14. Monoblock jar 16. Supporting prisms of + ve group 16. Inter-cell connector 17. Terminal lug 18. Screw 19. Washer 20. nut 21. Rubber packing 22. Sealing compound. Discharging: When the cell is fully charged, its positive plate or anode is Pb02 and the negative plate or cathode is Pb. When the cell discharges i.e. it sends current through the external load, then H2SO4 is dissociated into positive H2 and negative S04 ions. As the current within the cell is flowing from cathode to anode, H2 ions move to anode and SO4 ions move to the cathode. At anode (Pb02), H2 combines with the oxygen of Pb02and H2SO4 attacks lead to form PbS04. CHARGING When the cell is recharged, then H2 ions move to cathode and S04 ions go to anode and the following changes take place: Hence, the anode and cathode again become PbO2 and Pb respectively. It will be noticed that during charging : The anode becomes dark chocolate brown in color (Pb02) and cathode becomes grey metallic lead (Pb)Due to consumption of water, specific gravity of H2SO4. is increased There is a rise in voltage, Energy is absorbed by the cell Efficiency: Ideally, the charging and discharging processes of the lead-acid system should be reversible. In reality, however, they are not. Some of the electrical energy intended for charging is lost in the internal resistance and is converted to heat. When hydrogen is lost, it also represents an energy loss. Typically, the charging process is about 95% efficient. The discharge process also results in some losses due to internal resistance of the battery, so only about 95% of the stored energy can be recovered. The overall efficiency of charging and discharging a lead-acid battery is thus about 90%. Since battery losses to internal resistance are proportional to the square of the current, this means that high current charging or high current discharging will tend to result in higher internal losses and less overall performance efficiency. Amount of stored energy: The amount of energy stored in a battery is commonly measured in ampere hours. While ampere hours are technically not units of energy, but, rather, units of charge, the amount of charge in a battery is approximately proportional to the energy stored in the battery. If the battery voltage remains constant, then the energy stored is simply the product of the charge and the voltage. Effect of DOD on Life-Cycle: The following Figure shows how the depth of discharge affects the number of operating cycles of a deep discharge battery. The PV system designer must carefully consider the trade-off between using more batteries operating at shallower discharge rates to extend the overall life of the batteries vs. using fewer batteries with deeper discharge rates and the correspondingly lower initial cost. Lead-acid battery lifetime in cycles vs. depth of discharge per cycle Vented and nonvented batteries: In certain lead-calcium batteries, minimal hydrogen and oxygen are lost during charging. This means minimal water is lost from the electrolyte. As a result, it is possible to seal off the cells of these batteries, making them essentially maintenance free. The trade-off, however, is that if these batteries are either purposely or inadvertently discharged to less than 75% of their maximum charge rating, their expected lifetime may be significantly shortened. Lead-antimony electrodes, on the other hand, may be discharged to 20% of their maximum rating. This means that a 100 Ah lead-calcium battery has only 25 Ah available for use, while a 100 Ah lead-antimony battery has 80 Ah available for use, or more than 3 times the availability of the lead-calcium unit. However, the lead-antimony unit produces significantly more hydrogen and oxygen gas from dissociation of water in the electrolyte, and thus water must be added to the battery relatively often to prevent the electrolyte level from falling below the top of the electrodes. Water loss can be reduced somewhat by the use of cell caps that catalyze the recombination of hydrogen and oxygen back into water, which returns to the cell. Chemistry of the Nickel Cadmium Storage Battery: Ni-Cd batteries use nickel oxi-hydroxide for the anode plates and finely divided cadmium for the cathode plates. The electrolyte in the Ni-Cd system is potassium hydroxide (KOH). The NiOOH anode is generally made of nickel fibers mixed with graphite- or nickel-coated plastic fibers. Small quantities of other materials such as barium and cobalt compounds are also added to improve performance. The cathode is also frequently made of a cadmium-coated plastic fiber. If the cathode is not a coated plastic, then it is commonly mixed with iron or nickel. The fiber structures of anode and cathode maximize the surface area while minimizing the amount of relatively expensive nickel and cadmium required for the electrodes. On discharge, the NiOOH of the positive plate is converted to Ni(OH)2 and the cadmium metal of the negative plate is converted to Cd(OH)2. The basic reactions are: At the positive plate: NiOOH + H2O + e- = Ni(OH)2+OH At the negative plate: Cd + 2OH- = Cd(OH)2 + 2e- Overall: 2NiOOH + Cd + 2H20 = 2Ni(OH)+Cd(OH) The voltage of the fully charged cell is 1.29 V. Unlike the lead-acid system where the specific gravity of the electrolyte changes measurably during discharge or charge, the KOH electrolyte of the Ni-Cd system changes very little during battery operation. Ni-MH: (Nickel Metal Hydride) ` Another technology that is becoming very popular, particularly in smaller applications such as camcorders and laptop computers, is the nickel-metal hydride (NiMH) battery. This battery replaces the cadmium cathode with an environmentally benign metal hydride cathode, allowing for higher energy density at the cathode and a correspondingly longer lifetime or higher capacity, depending on the design goal. The anode is the same as in the Ni-Cd cell and KOH is used as the electrolyte. The overall discharge reaction is MH + NiOOH = M + Ni(OH)2 Lithium Ion (Li-Ion) Battery: Lithium-Ion battery is an advanced battery. Lithium ion batter has high energy density, low self discharge and no memory effect. These batteries are used where smaller and light weight batteries are required such as cell phones and laptop computers. However the main disadvantages of these batteries are the high price and fewer charge/discharge cycles

Right time to use Solar Photo Voltaic (PV) panels and Solar System Solution for power and electricity

. What will happen when the fossil fuel and other resources of power and electricity will end within few years? With the current world situation this question has the most logical base and why not the reserves of crude oil is over 1000 billion barrels that is available for usage and it is assumed that with the current utilization of 84.1 millions barrels a day, the world can run only another 32 (Thirty Two) years. After the stock report of fossil fuel; let’s check out where this fuel is utilizing: - the main consumption of fossil fuel is to produce the power and electricity. The second most usage is to run the vehicle and to run a smooth transportation system too. Other than these: mills, factories, heavy industrial instruments and equipments are run by the fuel. So, it is natural to come in mind what will happen after 32 years from now when we will finish off all the reserve of oil. Will we stop our power and electricity production? Will we stop the heavy industries? Will we stop the transportation and vehicle? Any one can guess that is not possible for us. World can’t pass a second with out power and energy nowadays. So, there is need to use of alternative and renewable energy resources to make substitute of the fossil fuel and the coal & natural gas. The sustainable renewable energy is getting popular as clean and green energy. Most of the countries are investing on this natural and renewable energy sector. There is no other way left for the human civilization ahead other than this. The next generation survival is depending on the perfection of proper utilization of invested capital in research of sustainable and renewable energy resources production and implementation system. USA president Mr. Barak Obama called for the country to reduce its oil import by one third by the year 2025. This is not that they are in short of budget for buying oil from other countries but they would like to secure its energy supply in the future. May be question will arise how? We can mention Mr. Obama’s speeches here,” When I was elected to this office, America imported 11(eleven) million barrels of oil a day. By little more than a decade from now we will cut that by one third”. Actually his emphasis on using of alternative of oil and fossil fuel; he said “The only way for American energy supply to be truly secure is by permanently reducing our dependence on oil. We are to have to find ways to boost our efficiency so we use less oil. We have got to discover and produce cleaner renewable sources of energy that also produce less carbon pollution”. He said that meeting this new goal of cutting US oil dependence depends largely on two things finding and producing more oil at home and reducing our dependence on oil with cleaner alternative fuels and greater efficiency. The USA president pointed on not to make a quick fix of the solution. Here we can mention another project that is completely hydro project and the location is in Himachal. This project is established by a consortium of TATA Power and Norwegian hydro power company. This project is build to produce 236 Mega Watt of electricity in Chenab Valle in Himachal Pradesh, India. In Srilanka rural electricity schemes has launched very recently. Several projects are going to establish by the government of Srilanka to achieve target of 100 percentages electricity needs of country’s rural sectors by 2012 set by Minister Patali Chapika Ranwake. The 4th project is for lighting Srilanka, Ranpura, Kague, Central province. The rural electricity project No.8 issued by the power and energy commission is the project under which new electricity connection had been provided for 720 houses in the Galle and Matara districts. There is a plan to another 516 electricity schemes of Rs. 85.7 million are in operation covering Elipitya, Nagoda, Karon, Deniya, Yakkalamulla,Beddegama and Thavalama divisions in the Gale district. While 203 electricity schemes will be started at the cost of Rs. 134.1 million of cover Kotapola, Pitabed, Passara, Dickweili and Akuresra DS divisions in Matara district. The International Energy Agency 794(IEA) is saying that the wide spread development of “Smart Grids” networks that monitors and manage the transport of electricity from all sources to meet the varying electricity demands of end users is crucial to achieving a more secure and sustainable future. Not only that the World Bank has taken an initiative to allocate the loan and subsidies in the sector of renewable energy nowadays. The IMF has prepared fund for set up the renewable energy plant, such as; the electricity production by the photo voltaic (PV) solar cell
I have tried to give some detail discussion and information in this article so that people can get a general idea about the solar panel that is used for generation of electricity. Basically the solar Photovoltaic (PV) or solar cells are PN junction Semiconductor devices. It converts sun light into direct current electricity. There are some types of solar cells or PV solar panels in market. Such as:

Mono Crystalline Solar cell


Poly Crystalline Solar Cell


Amorphous silicon solar cell


Flexible amorphous silicon


We can remember that one silicon solar cell produces 0.5V to 0.6V; these cells are combines together to get a module. Usually 33/36 cells are connected together to make one module. This connection are made keeping the fact in tact the cells are connected electrically in series and/or parallel circuits to produce higher voltages, currents and power levels. One module is capability to produce enough voltage to charge 12 volt batteries and run pumps and motors. The PV module is basic building block of a PV power system. Most of the time PV modules are combined in series parallel manner to make PV array of required power complete power-generating unit.
For two cells connected in series, the current through the two cells is equal. The sum of total voltage produced is the total of the individual cell voltages. As the current should same, a mismatch in current means that the total current from the configuration is equal to the lowest current.
Incase of parallel connected solar cell the voltage across the cell combination is always the same and the total current from the combination is the sum of the currents in the individual cells.
The performance of PV modules and arrays are generally rated according to their maximum DC power output (watts) under. Standard Test Conditions (STC).
Standard Test Conditions are defined by a module (cell) operating temperature of 25o C (77 F), and incident solar irradiance level of 1000 W/m2 and under Air Mass 1.5 spectral distribution. Since these conditions are not always typical of how PV modules and arrays operate in the field, actual performance is usually 85 to 90 percent of the STC rating.
Today’s photovoltaic modules are extremely safe and reliable products, with minimal failure rates and projected service lifetimes of 20 to 30 years.

With the above PV modules the solar systems and electricity generating solutions are developed.
These solutions can be different in category. Following is the category of solution those are possible to develop usually. They are:
1. Stand-alone PV systems
(a) Simple single module DC system (PV Home system)
(b) Large DC PV system
(c) PV system for DC and AC power

2. Hybrid PV systems:
(a) Hybrid-PV diesel
(i) Hybrid PV-Diesel system for DC and AC power
(ii) Hybrid PV-Diesel system for DC and AC with generator
for rectified DC
(c) Hybrid PV-Thermal systems
(d) Hybrid PV-Wind systems

3.Grid-connected PV power systems
(a) Self-commutated
(b) Line commutated

> Simple single module DC PV systems (PV Home systems) are used for low cost rural electrification. Usually a single module is connected to the load for sunny day use.

> Simple single module DC PV system (PV Home system) is connected to a single low cost battery through a simple charge controller as the regulator that is connected to a CFL. The regulator may have a relay that could tern off the light if the battery voltage became too low. The user would have to wait until the module charged the battery back to an acceptable intermediate voltage before they could turn on the light again.
> Large DC PV power system consists of large number of modules and large number of batteries to drive heavy DC loads. A large heavy duty controller having high current driving capability is required. Usually Loads are connected through the charge controller via DC circuit breaker distribution box.
> PV system for DC and AC power consists of large number of modules. Charge controller regulates the charging and discharging of the battery and the DC loads are supplied power through controller. Inverter generates AC power for the AC loads such as computers, fax machine, radio, TV, VCR and CD players.

Hybrid PV-Diesel system

(i) Hybrid PV-Diesel system for DC and AC power:
Instead of relying purely on PV system for power, a system can be designed with other generators available as well. A common choice is a diesel generator. This generator produces AC power for AC loads which can be passed directly on to AC loads through transfer switches. Generator power can also be used after (converting AC to DC) rectification to charge batteries or to supply required DC input to the inverter.
(ii) Hybrid PV-Diesel system for DC and AC with generator
for rectified DC
A hybrid system can be designed to have the generator act only as a battery charger. AC power is not used to run the AC loads. All AC loads are driven by the power generated by the inverter only. The generator is turned on when the battery voltage is very low or weather is bad. After rectification generator output is used to charge the battery.
The generator needs to operate only for few hours to recharge batteries.
Generator is operated at its full rated output for maximum output and
long life. When batteries are sufficiently recharged, the generator is turned off, and the finishing charge is supplied by the solar modules. If the bad weather continues, the generator is turned on again for a few days, and repeats the charging process. In this way the battery is kept fully charged having longer useful life.

(iii) Hybrid PV-Thermal systems
Hybrid PV-thermal systems, sometimes known as hybrid PV/T systems or PVT, are systems that convert solar radiation into electrical and thermal energy. These systems combine a photovoltaic cell, which converts electromagnetic radiation (photons) into electricity, with a solar thermal collector, which captures the remaining energy and removes waste heat from the PV module. Photovoltaic (PV) cells suffer from a drop in efficiency with the rise in temperature due to increased resistance. Such systems can be utilized to carry heat away from the PV cells thereby cooling the cells and thus improving their efficiency by lowering resistance.
Hybrid PV-Wind systems
There are some places where wind speeds are often low in periods when the sun resources are at their best. On the other hand, the wind is often stronger in seasons when there are less sun resources. That can make solar PV-wind hybrid solutions an alternative to consider. Even during the same day, in many regions worldwide or in some periods of the year, there are different and opposite wind and solar resource patterns. And those different patterns can make the hybrid systems the best option for electricity production.
Hybrid PV-Wind system is the combination of PV and wind turbine for the generation of electricity.
Grid-connected PV systems

DC power generated by PV is converted into AC and is supplied to the national grid. Energy storage is not necessary in this case. On sunny days, the solar generator provides power, e.g., for the electrical appliances in the house. Excess energy is supplied to the national grid. During the night and overcast days, the house draws its power from the grid. In this way, the electricity grid can be regarded as a large “storage unit”. In the case of a favorable rate-based tariff for PV electricity, as in force in some countries, it is more advantageous to feed all solar electricity into the grid.

Grid-connected PV systems can be subdivided into two kinds

Decentralized Grid-connected PV systems and
Centralized Grid-connected PV systems

Single phase less than or equal to 25kW
Three phase less than or equal to 300kW

Decentralized Grid-connected PV systems

Decentralized Grid-connected PV systems have mostly a small power range and are installed on the roof-top of buildings (roof-top or flat-roof installation) or integrated into building facades.


For example, in Germany around 80% of the more than 50,000 existing grid-connected PV systems are installed either on the roof-top of a building or integrated into a building façade. The benefit of the installation of a PV system into or onto a building is that no separate area for the solar generator is needed.

Central Grid-connected PV systems:

Central Grid-connected PV systems have an installed power up to MW range. With such central photovoltaic power stations it is possible to feed directly into the medium or high voltage grid. Mostly central photovoltaic power stations are set on unused land, but in some cases an installation on buildings, mostly on the flat roof of greater buildings, is also possible.


The main equipments in a solar home and commercial system connection set-ups are:
1. PV solar panels/module
2. Battery for storing the electricity
3. Charge controller for the battery indicator
4. Inverter for converting the DC current to AC out put usage equipment
5. Accessories as cable, switch board, switch, clip, array junction box for large system, main junction box, and steel frame structure to set-up the PV panels and some more as required to design and looking the solution in descent shape.