Experimental Performance Investigation of Combined Desalination and Power Generation for Application with Geothermal Hot Water Springs

This paper presents experimental performance data of a total flow combined desalination and power generation system. A two-phase flow simple reaction turbine has been used in this system which operates on the trilateral flash cycle. Hot saline water is used as the working fluid. The hot water supply temperature is varied from 94ºC to 97ºC, while the condenser is maintained at about 35ºC to 45ºC. This paper examines the concept of using the trilateral flash cycle for combined desalination and power generation from saline water in the salt affected areas using geothermal energy. The basic working principle of the combined desalination and power generation system is presented followed by discussions of the governing equations and the thermodynamics of the proposed system. Experimental setup and the test results are briefly explained to give an idea of the performance of the proposed system in a laboratory scale. Later it is shown how a combined desalination and power generation system can be coupled with conventional solar water heaters to boost the fluid temperature when the geothermal resource is at low temperature. Following the introduction of this concept the preliminary design is presented for combined desalination and power generation plant that would use saline water from hot water springs in the western coast of India and provide drinking water for a small coastal village with 20 houses (i.e. approximately 80 people with drinking water need of around 3 L/day/person). Most of the hot water springs along the western coast of India have temperature of around 60ºC and hence possibility of boosting the temperature using bio mass or solar thermal energy will also be explored.