India: Solar Water Heaters Developed by Jail Inmates
Inmates of the Central Jail in Bhopal in the Indian state of Madhya Pradesh developed and installed a centralized hot water system with a daily capacity of 2,500 litres at the jail, which was then inaugurated in March by Shri Raghavji, Finance Minister of Madhya Pradesh.
Photo: Central Jail, Bhopal
After successfully producing a 200-litre solar thermal prototype, inmates of the Central Jail in Bhopal in the Indian state of Madhya Pradesh developed and installed a centralized hot water system with a daily capacity of 2,500 litres at the jail, which was then inaugurated in March by Shri Raghavji, Finance Minister of Madhya Pradesh.
The system provides the 3,000 jail inmates with hot water for the preparation of tea and meals. The creative mind behind this project is Jail Director Prem Lal Pandey, who holds a Master’s degree in Radio Physics and Electronics. According to Pandey, the prison can save about 3.5 Liquified Petroleum Gas (LPG) cylinders per day by having set up the installation.
A special feature of the new system concerns the use of steel tubes: Each of the collectors contains 14 of them. Each steel tube is 6 ft. long, painted in black and possesses an inner diameter of 17 mm, compared to the 8 to 12 mm of a copper tube used in a common flat plate collector. “We know that copper has the better absorptivity,” Prem Lal Pandey states, “but it is not relevant how much time it takes to heat water. What matters is the size of the black surface that absorbs and transfers the heat.” The system can achieve a maximum temperature of 780C, according to Pandey. Its inner tank is made of HDPE (High Density Polyethylene), which has been suitably insulated by glass wool.
It is the difference in costs between copper and steel that makes the system a simple choice of economics. And, most of the central jails have a basic workshop, which means that the basic engineering tools and welding facilities for the production of the collector panels are already available on site. Manufacturing inside jails is additionally a tax-free business and involves no labour costs, Pandey explains. Hence, the costs per system add up to roughly INR 12,000 (EUR 200), compared to the INR 20,000 (EURO 340) required for producing a flat plate collector in a normal Indian factory.
Due to the promising results of this first solar-heated central hot water system, the Bhopal jail has already set itself far-reaching targets by the end of 2010: Pandey intends to supply all 8 central jails in Madhya Pradesh with solar systems possessing a capacity of 2,500 litres per day, as well as deliver solar water heaters with a capacity of 1,000 litres per day to 22 district jails and 500-litres units to the 92 subordinate jails of the state.
