The renewed growth of the Indian solar thermal market has existing manufacturers expanding their production capacities and integrating vertically. Solar water heaters based on vacuum tube collectors are a popular product, already covering around 40 % of the newly installed 1 million m2 collector area in 2011/2012, according to estimations by market stakeholders. An example is Inter Solar Systems from the northern Indian city of Chandigarh. The company has invested INR 8.6 million (about EUR 120,000) in a completely new and semi-automated solar tank production plant, which was commissioned at the end of last year. The photo shows a punching machine for vacuum tube collector tanks.
Inter Solar Systems started in 1997 with the production of flat plate collectors and quickly became the largest manufacturer of solar collectors in northern India. In 2010, the company began to import vacuum tubes from China while reaching ever larger sales volumes each year. Davinder Kaushal, Managing Director of Inter Solar Systems, says that planning the new tank manufacturing plant started in March 2012 and by November 2012, production was in full swing. The company focuses on 100 and 200 litre tanks for residential solar water heaters. Its annual production capacity is nearly 6,000,000 litres, which means 30,000 to 60,000 tanks per year.
The tanks are welded from stainless steel using PUF insulation. They are solar tanks only, either combined with flat plate or vacuum tube collectors. Due to semi-automation, the company was able to triple its manufacturing volume while still employing the same number of workers the company started out with in its “traditional” production plant.
India’s sudden shift from flat plate to vacuum tube technology is clearly driven by economics. The association Solar Thermal Federation of India (STFI) estimates that the price of a solar water heater with a 100 litre tank and ten 85 mm vacuum tubes is about a third lower (INR 16,000 per system) than a typical solar water heater with 100 litres and one flat plate collector panel with 2 m2 (INR 22,000). The federal subsidy scheme supports the trend towards vacuum tubes by granting a relatively high subsidy for the cheaper vacuum tube collector systems. A vacuum tube collector solution is granted INR 6,000, whereas the flat plate collector version receives only 10 % more, or INR 6,600.