31 May 2011
Air conditioning in India has not been common due to the extreme demand that it puts on a notoriously unreliable electrical infrastructure. But when you think about when air-conditioners (AC) would be most used in tropical countries like India, it coincides with the time when the sun is blazing its heat in the peak afternoon. Dr Upendra Kamdar, founder of Suryashakti Systems came up with air conditioning unit that is powered in part by direct solar heat. Because units often have to fit into limited space, the systems are small because solar PV panels and batteries are not needed.
The patented hybrid system works by using solar thermal energy to further expand the refrigerant coming out of the compressor, thus reducing the compressor load and saving electricity consumed by the system. Heat is absorbed from the atmosphere and also from hot air exiting from the air conditioning system, which is usually discarded as waste heat. As there are heat storage facilities available in the system, it works during night time as well and provides 48 to 72 hours back-up during cloudy days. The system can be effective in saving electricity consumption by up to 50% when compared to conventional air-conditioners.
Mr. Dinesh Kumar Shah, the owner of Vijay Stores, a World Magazine Subscription Agency from Gujarat, India, uses a hybrid solar air conditioner. The solar assisted AC units have been installed there for the past 1.5 years and have resulted in drastic reduction of the electricity bill. Mr Dinesh chose the hybrid systems because he runs air conditioning for 8 to 9 hours a day, and he was confident that he’d save 50% of his electrical use. He said with the new solar AC units he’s currently saving more than Rs 30,000 (Rs 15,000 per unit) per year. A price comparison of a 1 ton AC unit shows that the solar assisted AC from Suryashakti Systems costs around Rs 18-20 thousand (~60%) more than conventional units and the resulting savings as seen by Mr. Dinesh would mean a payback period of 1.3 years. The Indian Income tax law allows an 80% accelerated depreciation in the first year for solar systems and this makes it an even more attractive proposition.
When asked about the installation and maintenance requirements, Mr. Dinesh said that installation is similar to the normal AC unit. “The system is running smoothly and is in fact much less noisy,” he added. This system has also been installed in the offices of Indian Railways.
The latest development that this company is working on now is what Mr Kamdar describes as “100% solar ductable central AC system using solar thermal system and solar chiller”. This system can cool without the use of harmful refrigerants and also provide hot water for other purposes, resulting in a 99% reduction electrical energy use compared to conventional duct base AC. The system will be commercialised after he secures funding.
Written by Nilesh Jadhav--Contributing Editor - India