Research

Topics

Desalination, Energy, Environment, Thermodynamics, Heat and Mass Transfer

Adviser

John H. Lienhard V
MIT Website

PhD Committee

John H. Lienhard V (Chair)
Alexander Mitsos
Evelyn Wang
Mostafa Sharqawy (KFUPM)

Research Group

Lienhard Research Group Website
Center for Clean Water and Clean Energy
Rohsenow Kendal Heat Transfer Laboratory

Summary

Purpose: To develop a better understanding of the thermodynamics involved in producing potable water from seawater.

My primary research area is in the field of desalination (both seawater and brakish). Over the course of the last three years, I have studied various aspects of desalination. Here is a quick overview of my work.

During my master's work, I extensively studied humidification-dehumidification (HD or HDH) desalination cycles. HD desalination is a relatively simple technology that is based on the evaporation and condensation processes that are found naturally in the rain cycle. It has the added benefit of being easily powered using solar energy (heat). Initially, I looked at various HD cycles including both closed air open water cycles and open air open water cycles, both with either air or water heating. As part of the cycle analysis, I did an extensive Second Law studying as well as an optimization in order to determine the best possible performance for the base cycles. Results from this work is presented in the two IJTS papers listed below as well as in my Master's Thesis.

In addition to the base cycles considered above, I worked on optimizing HD cycles that are powered using a thermal vapor compressor, rather than a heater, and are hybridized with reverse osmosis. A patent has been filed for this technology and the results of the optimization will be presented at the ISHMT-ASME conference in December 2011.

For my PhD research, I switched from studying small desalination systems to studying large scale, combined water and power plants. Through a process known as cogeneration, both water and power can be produced in a single plant more efficiently than either can be produced independently in separate plants. Additionally, through hybridizing the desalination systems (i.e., using both thermal and membrane based technologies), water can be produced more efficiently. The primary goal of this research is to understand how the different systems interact and to determine the best operating conditions to produce water and power most economically.

In addition to looking at these complex systems, I have also carefully analyzed desalination plants from an irreversibility point of view. Starting with a black box separator, I properly defined the Second Law efficiency for a plant in which the product is mass of known composition (in this case, pure water), and then identified how losses, both within and external to the system boundary, result in decreased efficiency. I then applied this analysis to six different desalination systems. The results of this analysis is presented in the Entropy paper listed below.

Publications

  1. K. H. Mistry, J. H. Lienhard V, S. M. Zubair, Effect of entropy generation on the performance of humidification-dehumidification desalination cycles, International Journal of Thermal Sciences 49 (9) (2010) 1837--1847.
  2. G. P. Narayan, K. H. Mistry, M. H. Sharqawy, S. M. Zubair, J. H. Lienhard V, Energy effectiveness of simultaneous heat and mass exchange devices, Frontiers in Heat and Mass Transfer, 1 (2) (2010) 1--13.
  3. K. H. Mistry, A. Mitsos, J. H. Lienhard V, Optimal operating conditions and configurations for humidification-dehumidification desalination cycles, International Journal of Thermal Sciences 50 (5) (2011) 779--789.
  4. K. H. Mistry, R. K. McGovern, G. P. Thiel, E. K. Summers, S. M. Zubair, J.H. Lienhard V, Entropy generation analysis of desalination technologies, Entropy, 13(10) 1829--1864.
  5. K. H. Mistry, G. P. Naryan, A. Mitsos, J. H. Lienhard V, Multi-pressure humidification-dehumidification desalination using thermal vapor compression and energy recovery, Proceedings of the 21st National & 10th ISHMT-ASME Heat and Mass Transfer Conference. ISHMT_USA_015. 1--9. December 27--30, 2011, IIT Madras, India.

More information will be posted as the research progresses and papers are published. In the mean time, please feel free to contact Karan with any questions.

Patents

Master's Thesis

Second Law Analysis and Optimization of Humidification-Dehumidification Desalination Cycles
Direct download (PDF), DSpace@MIT