By S Paul
The celestial being, Sun (Bhanu in Sanskrit), has been dispensing energy in various forms for billions of years. In fact, it kick-started ‘life’ on this planet and has been sustaining it incessantly. Many cultures and civilisations including ours, has attributed Godliness to it and worship it. It is the Sun’s radiation in various forms that has provided us, living beings, with food, health and protection in all weather and terrain. Yet, we have failed to appreciate this bounteous and inexhaustible source of energy (Urja in Sanskrit). We failed to explore the full spectrum of the utilisation of this form of energy. Instead, we ventured to excavate from the bowels of our terra-firma; we discovered coal and petroleum as fossil fuels creating huge hollows in our Earth’s crust and pollution in its atmosphere. This extraction, in use all over the world, has become a part of human progress, but at a great cost of upsetting the balance of internal pressure of the Earth resulting in collapse of Earth crust causing tremors and climate changes.
The effort that goes into extraction of crude, its transportation, refining and storing for sustained use in transport and industry makes it very tedious and expensive. The process and use also causes great atmospheric and soil pollution.
The harnessing of solar energy in comparison is absolutely simple, clean and needs just collecting it, converting it with clean silent methods and storing for sustained use in the form of heat or electricity. The heat in turn maybe converted to drive our industrial engines or used by different methods to give us cooling, even refrigeration and stored electric power to be converted to alternating current to be part of our daily.
It is paradoxical that we, in order to overcome the soaring temperatures due to global warming, are increasingly resorting to the use of electricity powered air conditioners (AC) and Desert Coolers; both of which are not eco-friendly and add to the rise of atmospheric temperatures and cause paucity of water. The latter also becomes a cause of vector borne diseases. The AC also releases the refrigerant gases through leakages; which trap the Earth’s surface heat and do not let it dissipate into the space. The production of electric power, using petrochemicals also releases gases adding to global warming. Therefore, we are almost committing ‘hari-kari’, the Japanese name for self-destruction.
I feel that by discovering the means of utilising this abundant solar energy, we can save the planet from becoming a cemetery.
An air conditioner works on the basic aim of reducing ambient air temperature. The major components of an air conditioner are: condenser (compressor), expansion valve and evaporator. A refrigerant gas is commonly used for cooling, whereas a thermostat is employed to monitor and regulate the temperature. Atmospheric air is passed over evaporator coils containing the refrigerant, which help in absorbing the heat from the air and cools it. The compressor (condenser cum accumulator) pressurises the refrigerant and pushes it through a micro hole called ‘venturi’. The sudden expansion of this gas causes sudden drop of temperature which cools the atmospheric air in the room. The principal is the same if we have noticed in our gas filled sprayers that it gets noticeably cold when the spray is released. This cycle continues till the indoor is cooled. The main difference between the conventional electrical AC and the Solar AC is that instead of a motor compressor (consuming electric power) solar heat is used to push the refrigerant through the venturi to cool.
There is a vast field of refrigeration from making ice to cooling human habitats to providing cold storages for preservation of food and medicines to industrial plants cooling to cryogenics (achieving super refrigeration to the tune of minus 300 degree Celsius). There are other methods of achieving refrigeration used for various purposes. These are Thermo-electric refrigeration (no moving parts, no gas, the principle is cooling by passing electricity between two dissimilar elements strips), Magnetic refrigeration (Certain alloys like Gadollium are subjected to changing magnetic field to cause extreme cooling), Thermo-acoustic refrigeration (Sound is used to compress and expand a mix of inert gas which gets heated up and makes solid stack of compound cool at the other end), Elastocaloric refrigeration (heating and cooling takes place by subjecting a solid to mechanical stress changes) and Laser based Refrigeration (Cooling is obtained by subjecting special micro-crystals doped in certain salts to laser rays). All these different types of refrigeration are used in cryogenic research and space exploration and are pollution free. Solar AC is simplest and cheapest among these.
Iceland derives all of its energy for electricity and home heating from geothermal and hydroelectric power plants. Its renewable power plants like the geothermal plant at Blue Lagoon even draw significant amounts of tourists every year. Sweden has increased its investment in solar power, wind power, energy storage, smart grids, and clean transport with an ambitious goal: eliminating fossil fuel usage within its borders. Costa Rica is able to meet a large part of its energy needs from hydroelectric, geothermal, solar and wind sources. The country aims to be completely carbon-neutral by the year 2021 by running on 100% renewable energy for more than two months twice in the last two years. Nicaragua has a number of volcanoes, making geothermal energy production viable and it has also invested in wind, solar, and geothermal energy. Its aim of being 90% renewables-powered appears to be an achievable goal. United Kingdom is a windy place and using a combination of grid-connected wind farms and standalone turbines, the United Kingdom now generates more electricity from wind farms than from coal power plants. Germany looks set for a bright future with solar energy. Its renewable energy output including solar has increased more than eightfold since 1990. Uruguay has invested heavily in wind and solar power, without using subsidies or increasing consumer costs. And as a result, it now boasts a national energy supply that’s 95% renewables-powered, achieved in less than 10 years. Denmark plans to use wind power to achieve 100% fossil-fuel-free power generation by 2050. Morocco is a country with an abundance of sunshine (up to 350 days a year), so it has wisely decided to invest heavily in solar powered energy production. Combination with their wind and hydro production facilities, it predicts to produce enough energy for more than one million Moroccan households by 2018. Why then can’t Bharat become a pioneer as a Solar energy based developed nation?
The conventional air conditioner of 1 ton capacity, if used for 8 hours per day with an input power of 1500W will consume electricity at the rate of 12 KWH per day. In comparison, the solar air conditioner will use only 500W per day (for using a small pump and fan). Based on western and Chinese designs, window and split Solar AC, are available in the market, even in Bharat, but are more than 2 times the cost of conventional ACs. Calculating the power consumption and the maintenance cost, a Solar AC, at present, pays for itself in about 8 years of use. If by indigenisation and entrepreneurial research this cost is brought down it may replace the conventional AC and also desert coolers in vogue; saving so much on individual and national level power consumption. Imagine, by switching over to solar system of refrigeration we can save so much on electric power, get rid of so much pollution, provide portable mini ACs even for use in camping outdoor, for use in remote villages, for preservation of food and agricultural products and the list goes on. If our young entrepreneurs and experienced refrigeration industry can work and bring down this cost we can pioneer its use world over. It is time to win over the world market.
Under the recently announced startup enterprise financial assistance by the central government and the (Mukhyamantri Saur Swarozgar Yojana) ‘Chief Minister’s Solar Self employment scheme’ in Uttarakhand why don’t our entrepreneurs take this up? We can easily become the leading nation for producing cheap solar ACs and other Solar energy based systems like independent remote house hold power supply, Solar Cold storages & driers, Solar powered water pumps , Solar scooters/cars and many more.