Document Type: Research Paper
Reverse Osmosis Discipline, CSIR-Central Salt and Marine Chemicals Research Institute (CSIR-CSMCRI), Council of Scientific & Industrial Research (CSIR), Gijubhai Badheka Marg, Bhavnagar- 364 002, (Gujarat), India
With the increasing installed capacity of desalination, the greenhouse gas emission for generating the required energy to power the desalination plants is also becoming the focus of attention in the world community. Domestic reverse osmosis membranes have been very successful technology especially in the developing world to provide safe drinking water. The novel concept of photovoltaic powered RO with thermal energy recovery from the photovoltaic panel has been presented. The problem with photovoltaic technology is its sensitivity to temperature. The efficiency of the photovoltaic panel declines at higher temperature. The present paper demonstrates that the thermal energy can be captured by flowing water to maintain the temperature of the photovoltaic panel at the same time the captured thermal energy can be harnessed for useful purposes. The direct utilization of high temperature water is the most attractive option from an overall energy efficiency point of view. The present paper demonstrates that the captured thermal energy from the PV panel can be successfully utilized when cooling water is feed water to reverse osmosis. The higher temperature feed water to reverse osmosis decreased the energy consumption of reverse osmosis up to 28% and increased the total product water output by 20% with up to a 10oC rise in feed water temperature during the day. The paper also explains the sensitivity of membrane transport with temperature. The present paper opens the possibility of system development and poses the win-win combination of higher photovoltaic panel efficiency with the utilization of captured thermal energy which in turn curbs greenhouse gas emissions.