11 Oct 2008
07:44 pm IST

Have you heard of Anergy and Exergy?

You know that energy can neither be created nor be destroyed. Therefore we can only ‘convert’ energy. In a true sense, there is nothing that can be called ‘creation’ or ‘generation’ of energy. It is possible to transform one kind of energy to another type of energy. The kinetic energy of water can be changed into electrical energy. Solar light energy can be translated into heat energy. Heat energy can be transferred into electrical energy.

In the process of such translation only a portion of primary source gets switched into new form, being named as ‘exergy’ and the other part remains unaltered, being termed as ‘anergy’.

750 to 800 million vehicles on earth are operated with an exergetic efficiency of not more than 20%. 80% of the energy of the gasoline or diesel fuel is converted into heat. More than 90% of energy utilized by a 40 watt bulb results in heat energy, making it a more efficient electric heater than a light bulb.

Plants know how to convert solar energy into useful energy through the process of photosynthesis. Their ability to maximize ‘exergy’ is still being studied by scientists and biomimicry specialists. The exergetic efficiency of plants is believed to be very high. Taking their help to reduce urban heat island effect in buildings can be a novel way of investing in Negwatts.

Academy of Sciences Museum has finally opened in San Francisco. This is the largest LEED platinum rated green building in United States. Its roof has been covered with 1.7 million native plants. These plants are contained in place by 50,000 porous, biodegradable trays made from tree sap and coconut husks. The roof reduces the Urban Heat Island effect and reduces the building’s temperature by an average of 10 degrees compared to a regular building. This is a clever use of solar heat, which would have otherwise been technically ‘wasted’.

Recovering waste heat is a study in itself. A few days ago, researchers led by Northwestern University discovered that adding two metals, antimony and lead, to the well-known semiconductor lead-telluride, produces a thermoelectric material that is found to be more efficient at high temperatures than existing materials. This is an important breakthrough that will help recover good amount of automobile’s heat energy. We could hope that some day soon the car’s air conditioner can be run using this breakthrough.

Consider how much more primary energy is required to send us 1 unit (1 KWh) of energy to our house. It could be as high as 1:10. Bearing in mind that there is Anergy at every stage of energy transformation should we not motivate ourselves to avoid wasteful energy?

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Be the change,
Krish Murali Eswar.
"A small body of determined spirits fired by an unquenchable faith in their mission can alter the course of history. Gandhiji."