Showing posts with label renewable energy. Show all posts
Showing posts with label renewable energy. Show all posts

Friday, 5 May 2017

LEDs and life cycle costing

It’s late in the evening. The sun is going down steadily and darkness is slowly creeping in your room. You move over to the switch and turn on the lights. A flicker of light and then darkness prevails. The bulb had failed. It’s still not late enough for the shops to close, so you head out to buy a new light bulb. The shopkeeper shows you the “latest low- energy technology” which is 10 times costlier than your regular bulb. You ignore it as usual and buy the cheap light bulb and go home. Sounds familiar?
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They say technology comes at a price. But is it really true? A lot of time and energy is spent in developing new and improved systems and it is natural that a higher price is demanded for it. Almost all of the legitimately developed new technology assist the user in a better way than the existing ones. They are either more resource efficient, are more accurate and precise or simply offer a better user experience and it is precisely these features that result in a higher price being quoted for these new systems. But if a new technology is more efficient, doesn’t it mean that it will result in savings during its usage? Is it cheaper in an overall context which in other words is called Life Cycle Costing?
In this article, we are going to see how technology has changed in the area of household lighting systems and is it really worth paying more for new technology.
In the late 90’s and early 2000’s one of the most commonly used form of domestic lighting in India apart from the tube-lights were the incandescent bulbs. These gave a typical yellowish light and would become very hot as one used it for prolonged duration. A slight fluctuation in voltage or a small drop of water on the bulb’s surface would immediately damage it. These were typically 40W or 60W bulbs. They are still manufactured and probably used by a lot of people in the country. These were quite cheap and as of 2017, cost around ₹15 only.
In the mid 2000’s CFL or Compact Fluorescent Lamps started becoming more popular. They were already there in the market but took some time to gain popularity due the exact reason why LEDs have taken so much time to become popular today. These used a similar technology to the aforementioned fluorescent tube-lights. However, their initial cost was much higher than the conventionally used incandescent bulbs. People would say things like “You have to pay for the technology” or “technology comes at a price”. However, it was quickly proved that although one pays a higher price for the CFL they would last longer, were less prone to damages and gave same amount of light while consuming lesser power. A typical 15W CFL consumes 1/4th the power of a 60W incandescent bulb but gives more light than it. This led to significant savings in the long run.
Fast forward to 2010 and onward and a new technology was gaining popularity. Light Emitting Diodes or LEDs were making their way in into the lighting market. Initially they were really expensive but their key feature was almost 1/3rd power consumption of CFL and less than 1/10th power of an incandescent. Most large scale industries realized the potential for savings and started switching over to LED lighting however up till 2015-16 LEDs still hadn’t made it into the households. As of 2017 too they are not very commonly seen in houses. The reason is the same old misconception that it is “expensive” but it certainly is not! LED lights last for 10 years as compared to just about a year of incandescent. Hence, it is important that one compares the Life Cycle Cost and not make a decision just based on the initial cost.
Let’s compare. The following is a simple table that compares these three types of lighting systems along with their costs and lighting levels (Lumens).
Values in red colour are extrapolated.
It can be observed from the above table and the pictures that a 60W incandescent bulb is capable of giving 710 lumens of light and costs ₹15 only. However, we know from experience that it lasts for just about a year. A 15W CFL on the other hand costs around ₹120, consumes only 25% of the power of incandescent bulb but gives out 810 lumens of light. It lasts for around 2 years.
Coming to the LEDs, one can see that two LEDs have been compared. The first one is a 4W LED bought in 2014 whereas the second one is a 9W LED by the same manufacturer bought in 2017. The 4W LED was bought in 2014 for a whopping ₹450! The 9W LED was bought for ₹150 in 2017. Although the M.R.P on the 9W LED reads ₹250, the shopkeeper was happy to offer 1 lamp for ₹200, 3 lamps for ₹500 and 6 lamps for ₹900, which results in the lowest price of ₹150 per lamp. The reason behind explaining all of this is to throw some light on the rapid fall in prices of LED lamps. While LEDs were costing ₹ 113/ watt in 2014, they have fallen down to ₹ 17/ watt in 2017 which is an 85% drop in prices!
It is evident that LEDs are becoming cheaper by the day and the government as well as manufacturers are doing their part to make it affordable for the common man. But the question is, was it not affordable before? Did it not make financial sense in 2014 when it was costing ₹ 113/ watt?
Let’s have a look at the last column, LCC over a period of 10 years. This is the most interesting observation.
Taking current price of ₹150 for a 9W LED light, 2.7 hours of daily operation, ₹7/ kWh of average electricity cost and the life of 1, 2 and 10 years for the incandescent, CFL and LED respectively. It is observed that over a period of 10 years, an individual buying only 60W incandescent lamps would end up spending around ₹4,289 including the initial cost, cost of replacement every year and the electricity consumed. Whereas, an individual using LEDs would spend only ₹771 over a period of 10 years. Point to be noted that the time value of money and the ever increasing cost of electricity has not been accounted for. In an actual scenario the difference will be more significant.
For argument’s sake, if one replaces the cost of 9W LEDs by the actual M.R.P of ₹ 250, it still shows an expense of just ₹871 over 10 years as compared to ₹1635 for CFL and ₹4,289 for incandescent.
But the most interesting observation is this.
If one just takes the prices of the year 2014 when LEDs were “expensive” and do the same calculation.
It is observed that the LCC over a period of 10 years is almost the same as CFL and still much lower than an incandescent lamp. This just emphasizes the fact that the typical human mentality is to get bogged down by the initial cost of a new technology without analyzing the life cycle costing and making a poor choice. This is particularly true for new, resource efficient and clean technologies such as LEDs and solar power.
In the case of solar, people generally shoot it down assuming that it is very expensive. However, a solar power plant lasts for 25 years as compared to 5-6 years of a diesel genset. Taking into account the rising fuel prices, and genset maintenance expenses, it is clearly seen that a solar power plant is much cheaper. The same is the case with BEE star rated appliances. Although they are a tad bit expensive up front, they lead to an overall savings when one understands the life cycle costing.
In conclusion, adopting energy efficient technology is not an expense but an investment. One should always look into the LCC of an investment and compare it with existing conventional methods to get a true understanding. This will allow for faster adoption of energy efficient technology. Our country has its fair share of power woes and while the government is trying to do its part by offering subsidies and addressing power issues, it is up to the common man to be smart, understand the life cycle costs and make use of energy efficient technology.

Friday, 23 September 2016

DIY - Solar Phone Charging Unit


This article explains about how to make your own solar based mobile phone charging unit. The design is very simple and completing this should not take you more than 2 hours.

List of components required:
      1.       Solar panel : 3W,6V panel
      2.       Sealed Maintenance free lead acid battery: 6V,4.5AH
      3.       Diode: IN4001
      4.       DC -DC Step Down Buck Converter KIS3R33S Module 7V- 24V to 5V /3A
      5.       USB based mobile charging cable( Normal data cables will not work)
      6.       Connecting wires
      7.       Soldering kit

Circuit connections diagram:



Working principle:

Mobile phones have inbuilt batteries and they need to be charged every few days or every day depending on how often the mobile is used. Batteries can be charged only with Direct current whereas the electricity we get in our normal household sockets is Alternating current. A mobile phone charger does the job of converting AC to DC and keeping the output voltage and current levels suitable for mobile charging. Chargers typically have efficiencies ranging from 60-90% depending on the quality (This is why some of the chargers get heated up quickly)

On the other hand solar panels convert solar energy to DC electricity. With suitable circuitry we can store this DC electricity in an external battery and charge the mobile phone when ever required.

The selection of solar panel and battery depends on various parameters like number of mobiles to be charged and the voltage levels of the battery etc. We have used a 6V, 4.5AH battery which can charge a typical smart phone once every day.  A 3W 6V solar panel is chosen since that is enough to charge the external battery in 7-8 hrs. The solar panel is directly connected to the battery with a diode in between to avoid reverse flow of current from the battery to the solar panel when there isn’t enough sunshine and during night time.

A DC-DC converter module is used to convert 6V battery voltage to 5V output since mobile batteries are very sensitive to charging voltage and current( a normal car battery regulator can be used but the efficiency is very low)

Construction:
·      
            As shown in the circuit diagram, connect the positive end of the solar panel to the positive end of the diode (silver ring on the diode represents negative) and the negative end of the diode to the positive of the battery. The negative end of the solar panel can be directly connected to the negative terminal of the battery.

·         Solder the terminals and use insulation tape to make sure shorting of terminals doesn’t happen.

·         Identify the input side of the DC-DC converter and connect positive and negative of the battery to the positive and negative of the DC-DC converter input respectively.

·         The output of the DC-DC converter is a USB port where the charging cable is inserted. (Note: Normal data cables do not work so a simple charging only cable should be used)
·         If the connections are proper, you should be able to see a red light glow on the DC-DC board and your mobile phone should display charging.

·         We had used a voltage and current measuring device called a charger doctor at the output to verify if the voltage and current levels are in the suitable range. This unit is not required.




Try this fun project and let us know your experience or queries in the comments section below.

Where to buy?

4.       Diode IN4001,connecting wires, soldering kit and charging cable : Any regular electronics store

Thursday, 25 August 2016

Innovations in Energy Storage – Key to Renewable Energy Adaptation

Renewable energy (RE) is the source of energy that are naturally replenished and thus don't deplete. The most common types of RE are solar and wind. These are the ones that are predominantly used around the world today. While wind turbines harness the kinetic energy of the wind to convert it into electricity, solar technology has more variants. Both heat and light from the sun can be utilized to generate energy. Solar thermal and concentrated solar power use the sun’s heat to produce energy and work while Solar photovoltaics (PV) or commonly known as solar panels use the sunlight to produce electricity.

All those who have been fairly accustomed to the proceedings in the renewable energy technology understand the pros and cons. While significantly lower levels of environmental impact is a major advantage of RE, it still hasn’t picked up well enough and hasn’t quite been able to compete with the conventional sources (Coal, Gas, etc.). RE technology, or at least the two most popular ones, Solar and Wind have a major drawback. The sun doesn’t shine all the time and the wind doesn’t blow continuously. This makes the energy produced by these technologies intermittent. Add frequent weather changes and it can be observed that one cannot solely depend on these technologies for their energy needs. These cannot serve the base load. We still need coal, gas or nuclear powered plants to serve a steady, continuous base load.

Energy storage is considered as the answer to this problem. It is a well-known concept and the most widely used method of electrical energy storage are batteries.

Batteries have been used for many years now in a variety of applications. They have been improved significantly over the years, from bulky lead acid batteries to sleek and powerful Li-Ion batteries that are light weight. Batteries are a topic that has been subject to tremendous research. They may look like a simple device but they are quite complex in the sense that they get affected by too many parameters. The charging current, discharging current, operating temperature, depth of discharge, the duration for which it has been kept unused and the amount of variation in load are some factors that affect the life and efficiency of a battery. It is nearly impossible to get the best of everything and as a result, a typical battery works well for not more than 3-4 years. In the case of renewable energy, where a power plant lasts for about 25 years, a battery bank to store the energy is a great idea but it also means a recurring expense of replacing the batteries every 3 years. This increases overall project costs over the lifetime. That being said, a well-designed battery bank connected to a solar power plant will ensure a steady supply of power thus eliminating the intermittent nature of the energy generated. In order to do that, the batteries need to be lighter, cheaper and have a higher energy density (more storage in reduced space). Many organizations are currently researching batteries, from mobile phone manufacturers to electric car makers.

Li-Ion battery (left) and lead acid battery (right)


While batteries are capable of storing electrical energy, thermal energy storage requires a completely different arrangement. In a solar thermal device, which is equally intermittent, the heat generated while the sun shines may be stored in special arrangements for later usage. It is in some way like a thermos flask that traps the heat in the coffee and keeps it warm for a long time. There have been many materials and compounds that have been explored which can store heat or cold and release it according to the user needs. These are primarily Phase Change Materials (PCMs) that change phase (solid – liquid –gas) when subject to heat or cold and stay in the new phase for a considerable time till the energy is removed externally. Salts have been researched for this purpose. Excess heat from say an oven can be pumped into an insulated chamber of salt using conventional heat transfer methods. This melts the salt (solid to liquid). Due to insulation of the chamber, the heat that has been put in remains in for a considerable time. The heat from the molten salt can be extracted later using conventional methods and utilized for various processes. A technology like this will enable solar water heaters to provide hot water even during the night. Phase change materials are various compounds that work in different temperature ranges. They can be selected according to the application whether it is heating or cooling. PCMs have found niche uses in a wide spectrum ranging from lunch boxes to Neonatology. PCMs last for about 3-4 years which again leads us to a recurring expense every 4 years when integrated with a RE setup. A lot of effort is being put to improve the cyclic performance and durability of PCMs.

We might have also noticed that stone and concrete floors tend to get really warm during summers. For example, anyone who has been to the Taj Mahal will remember the hot marble floor on which one has to walk barefoot. Getting inspired from these, research is being done on thermal energy storage in concrete and stone blocks.

In conclusion, it is evident that a breakthrough in energy storage, whether thermal or electrical is the key factor that will lead to extensive adaptation of renewable energy systems. By addressing the core disadvantage of RE, i.e. intermittent nature of RE, energy storage technology might make all the difference in the years to come.