Solar thermal heating and freeze concentration for non-centrifugal sugar production: design and performance analysis

Non-centrifugal cane sugar (NCS), known as Jaggery, is a form of unre- fined sugar which contains molasses. The integration of renewable energy resources in the production of NCS, have been analysed. The work investigates the energy requirements of a system incorporating a freeze-concentrator and a solar thermal heater to reduce the reliance on the combustion of bagasse or other fuels in a Jaggery production process. Depending on the extent to which freeze concentration can be incorporated into the process, results show that the minimum theoretical energy required to produce Jaggery can be reduced by 91.30% overall. Although difficult in practice, this theoretical analysis demonstrates that the integration of freeze concentration close to the eutectic limit of concentration has significant advantages. For optimal configuration and ideal operation of the system the analysis reports a requirement of approximately 3.8 MJ to produce a kilogram of Jaggery from cane juice. When typical process efficiencies (furnace, boiling pan, solar thermal collector, and chiller) are included, the energy required ranged from 4.8–5.2 MJ/ kg Jaggery. This represents a potential energy saving in excess of 38 MJ/kg Jaggery and a fuel saving of more than 2 kg of bagasse/kg of Jaggery produced.