To say that solar energy is blazing across the Indian power generation landscape today is an understatement. Massively large power projects involving millions of rupees are being set up across the country everyday. However, almost all of these projects are based on the solar photo-voltaic technology and very few of them involve concentrated solar power.
The concentrated solar power (CSP) technology accumulates heat from the sun’s rays to a particular point, which contains water or other fluid flowing through pipes. CSP works by concentrating sun’s rays on a small area, which would otherwise be distributed over a larger area. This heat absorbing liquid will then transfer the heat to water, which in turn becomes steam and runs a turbine to generate power.
However, a typical concentrated solar thermal power plant needs a large infrastructure involving parabolic mirrors, heat insulated pipes to carry molten liquid, steam turbine and electric generator. Obviously these equipment are costly to manufacture and install, making the project economically unviable. Till now very few CSP plants have been set up in India due to their exorbitant capital cost. Fortunately, an innovation by a Nagpur-based SME has not only brought down the cost of CSP plants but also made them compact for small-scale applications.
Green Life Solutions has created a paraboloid solar reflecting dish concentrator with a downward facing conical cavity receiver at its focal point. Both the dish and the receiver are designed to absorb the maximum concentration of solar energy and to transfer it for useful application. Further, the concentrator has an inbuilt dual axis tracking system, which follows the sun to capture maximum amount of solar radiation throughout the day.
Green Life Solutions’ concentrated solar thermal (CST) technology consists of a parabolic dish collector, heat receiver, automatic dual axis tracking system, working fluid (oil/water) and circulation system. Its aluminum mirror dish has a unique paraboloid shape that maximizes the capturing of solar energy, while it is aerodynamically designed to take high wind loads. Each dish weighs around 140KG and occupies only 2 sq ft of foot print area, but it has the capacity to generate around 30Kg of steam, depending upon the solar radiation in that area.
Sudhir Sarawat from Green Life Solutions claims the overall conversion efficiency of the solar energy (DNI 700 W/m²) into thermal energy is 65%, which is way above other available concentrated solar thermal technologies. The receiver can withstand a temperature of upto 800 degree Celsius and generate a peak thermal power of 25,000 kilo calories. He states that Green Life’s CST dishes have an optimum dish size and modular design, which minimize maintenance efforts and are easy to transport and install.
The biggest advantage offered by the Green Life’s CST dishes is their affordable cost. The cost of manufacturing of each dish is INR225,000.00, which includes installation of dish and the steam generator equipment as well. These dishes are ideal for intense heat consuming industries such as dairy and food processing, power generation, chilling and heat exchange.
However, it is a surprise that this cost effective and revolutionary technology has not been popular in India. Solar experts are skeptical about the efficiency of Green Life Solutions’ concentrated solar thermal technology since the company doesn’t have many units installed.
Image sources –