Archive for June, 2009

Design 2

June 22, 2009

Design Principle – 2: Consider Energy requirement as a primary function.

The next principle that I would like discuss is considering the energy requirement as a primary function of design.

When we think of buying a car probably the first question that pops up in the mind is the ‘mileage’ that we would get. Why is that? This is because we understand that the cost of owning the car for the next 3 to 5 years would greatly depend on the cost of the fuel that we would use in running the car.

But do we ask the same question when we think of buying a house or a flat? Probably not! We don’t ask “What is the energy requirement per square foot?” But we would probably own this building for the next few decades and we would certainly consume a lot of energy in the process, which unfortunately has to be paid for. This important question is yet to pop up in the social consciousness.

Nowadays there is a lot of talk about carbon emission and carbon footprint. In simple terms it means that more energy (fossil fuel based) more the carbon we emit into the environment (carbon footprint).  Statistics show that 50% of the global carbon footprint comes is generated from buildings and 20% of the global footprint is generated by automobiles. Once we know this designers would become more alert about the energy per unit.  And this would save users a lot of money.

There is another interesting statistics. In India we consume 2.88 times as much energy to produce one unit of GDP as it does in the west or for that matter in other developed nations.

What does that mean? It means that manufacturing industries in India are at a severe competitive disadvantage when compared to their peers. It also means that it is time that we wake up and do something constructive. However, it is also clear that energy savings would not be achieved by putting up signboards asking people to ‘switch off’ electrical appliances when not needed. The solution lies in Design and Maintenance. We can design things in such a manner that we can reduce the requirement as much as possible and use whatever is available to the best possible advantage and maintain things in such a way that energy consumption is minimized and sustained.   

Let us illustrate the point with examples.

Example 1:

Modern air conditioners have redesigned the heat exchanger tubes in such a way (fluted inside) that the energy exchange is maximized through extended surface area and by inducing chaotic flows. This lowers the energy needed for cooling. Present day Godrej air conditioners serve as an example.

Example 2:

Modern air conditioners manufacturers have also introduced a variable speed electric motor that never actually stops and starts frequently and consume extra energy in the process. These motors run continuously — though at a very low speed when the desired temperature is achieved. As we know that electrical consumption of motor is proportional to the square of the speed. So the electric power consumption is saved in two distinct ways — a) avoiding surge currents during starts and b) lowering of the speed when not needed and by maintaining a steady state temperature distribution.

Example 3

By using natural light and wind we may not only improve the environment inside offices and factories but also reduce the electrical consumption to a great extent that would have otherwise been used up to heat or cool work spaces. A small example, that might be in order, is to minimize the use of glasses in a tropical climate. We use such concepts extensively while designing modern work spaces.

Example 4

Cleaning heat exchangers and condensers is a simple and effective way to reduce energy losses on the whole. 

Example 5

Proper lubrication of gear boxes can bring down the energy losses by as much as 5  to 10%.

Example 6

Lastly using solar power and proper insulation of pipes, floors, roofs and maintaining them in good order are other cheap and effective ways to reduce carbon footprints.  

These examples hopefully, illustrate that there are so many ways in which Design and Maintenance can help us to reduce the ever increasing carbon footprint and make our world more sustainable and habitable.  

Hence taking energy requirement as a primary design challenge and function is extremely important and all the more important in today’s context. It is therefore a basic principle of design and maintenance (design and maintenance are just inverted images of each other — both serving the same purpose).

dibyendu de

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Design 1

June 20, 2009

Design Principle 1 — Cleverly combine many small things to create a better effect than using one big thing!

Since this blog is all about Design Innovations in the manufacturing set up I thought that a good way to start would be to write about the various design principles, physical laws, techniques and methods we use.

Why is that?

This is simply because we don’t have much design tools available while we have tons of analytical tools. We now have so much analytical tools that one can really get drowned in it and however hard one might try he/she can never come out of it in a lifetime.

But this is not the case with Design tools! We have only a few of these — so few that we might not notice them at all.

But what is the problem?

Problem is that while we are now able to analyze anything to great depths we can hardly create the right solutions that would make our lives easy and our work more meaningful and productive. For this we need design tools. We need design philosophies. We need design methods and techniques and principles that would indeed help us to create good or excellent solutions to our present problems.

Therefore, I felt that there is a need to create a design tools that would be especially useful for engineers and manufacturing industries.

Engineering is a very creative profession. But many engineers hardly realize this. While artists play around with colours and musicians play around with notes and sounds and writers play around with words and characters engineers play around with physical laws and economics.

So let’s start playing with our Design Principle 1.

The Principle is: Cleverly combine many small things to create a better effect than using one big thing!

In a simple way all it means is that if we put together many small things the effect that we would get would be better than having one big thing.

Let us illustrate this concept with examples:

Example 1:
Many years back we used to have a single bulb to light up our rooms. If the room was large we thought of putting up a higher wattage bulb. That is if a 60 W bulb wasn’t good enough then use a 100 W bulb in its place. And if a 100 W bulb still does not light up the place then try out a 150 W bulb. We then realized that by scaling up in this manner the electricity bill at the end of the month only burns a bigger hole in our pockets.

So we then decided to use ‘tubes’. This did light up the rooms better than the bulb but illumination levels again became a problem with larger rooms. So we again started scaling up till we realized that we are back to square one — consuming a lot of electrical power.

We then came up with CFL — extra low wattage items with good illumination. But with one CFL we were illuminating only a part of the room — not the whole. We now got over this problem by placing a number of CFLs all round the room. With this we achieved the objective — right illumination and lower electricity bills.

What might we do next? Well, I think we would soon be using LEDs to light up the room in a much better way and use a lot less energy.

So by cleverly combining small things we get a better effect than one large thing.

Example 2.

Similarly, by using LEDs (small light devices) is not a new idea. But using LEDs in ordinary flash lights was a clever idea used by Everready company with their low cost flashlights. I purchased one and was pleased to have one. It lights up the place brilliantly and the batteries last over 6 months.

LEDs are also being used as traffic lights. It not only serves our purpose well but also cuts down on the electricity consumption. Again the idea is to combine many small things to be better than one large thing.

Modern cars also have started using LEDs as for the rear end lights. It does not matter if some of the LEDs are damaged or burnt out. The function of the rear light is intact.

Example 3

Computers now use this principle too. Engineers understood that we simply can’t go on increasing the size of the single processor and the related memory to go along with it. There is a limit to such growth. So they have started combining several smaller microprocessors together to get the same or better effect than having one single large microprocessor. So we have Core to Duo (means combining 2 processors) and Core to Quad (again meaning a combination of 4 processors) etc. Soon, we would be see Core to 64 and Core to 1000. This would certainly increase our computing power like anything and reducing power consumption.

Example 4

The idea is that there is always a limit to growth of any live system. Beyond a certain point the return is not proportionate to the effort, investment or power consumed.

Let us take another example. Solar panels might serve as a case in point. There was always a limit to the size of the solar panel. But recently, Shri Choudhury of West Bengal cleverly put together a large number of solar panels to create the world’s first 2 MW power plant enough to light up 2000 rural homes in India and around 500 urban homes while cutting down 7 tonnes of carbon dioxide which a 2 MW thermal power plant would have otherwise produced. This is a remarkable achievement. But again we would hit the ‘limit of growth’ with this technology. Can we build a larger power plant with the same technology. No. The cost would be prohibitive. So we are now thinking of using nano technology to make each solar panel more effective and smaller and less costly to make. We can then put these smaller pieces together to create a larger power plant which would be more efficient and reduce the carbon footprint drastically.

Example 5

We can then use the same principle to design more effective manufacturing systems at a lesser costs. Consider using a number of smaller number of blast furnaces to increase productivity, reliability and availability of a plant and at the same time offset the great costs of scaling up the system to have one large jumbo size blast furnace.

The concept of economics of scale and the concept low reliability of larger systems seem to falter with this logic of intelligently combining smaller objects.

Similarly, instead of having a larger press for producing rubber products we may have a small number of presses and combine them in a intelligent manner to improve productivity, performance and profitability. This is because the cycle time would reduce dramatically.

We can use this principle to excellent effect for designing many things that we use today, especially when money is hard to get.

We can use this principle for designing our roads, designing town water systems and designing buildings and definitely use it for designing machines and manufacturing systems.

This is a simple secret — open for extensive use!

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June 20, 2009

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