Concluding Remarks

A lot of research has been done to improve, upgrade and advance the thermody­namic efficiencies of the various technologies used in dual purpose power and water production plants. This study has contributed to the perpetual goal of reducing the per unit cost of power and water produced from dual purpose power and water pro­duction plants by investigating ways, methods, and mechanisms of improving the operating efficiency of installed capacities. Although major upgrades would require at least retrofits or plant redesign, the major issues tackled in this paper are more to do with improving operational practice by observing and using data and informa­tion from simulations. The underlying theme was that by improving the operat­ing efficiencies, the overall gain will translate to reductions in production costs, in particular reductions in per unit cost of both water and electricity produced in dual purpose water and power production plants.

A case study was used to illustrate how simulated data and information can be used to fine tune operations as well as identify optimization initiatives for; (a) im­proving operating efficiencies, and (b) reducing production costs in dual purpose power and water production plants. Opportunities for improving operating effi­ciencies related to plant configurations, parameter optimization as well as power and water production strategies were identified through numerical simulations and simulation modeling techniques. Numerical simulations have pointed out that there is surplus production of both water and power in the case study plant. Although the actual reasons for this surplus could not be determined through simulations, identi­fications of surplus production indicates the need for further investigations. In some cases, surplus could be produced as part of the production strategies. However, it has been indicated that in such cases, the minimum amounts of surplus as per design or operational issues should be scientifically determined to avoid unnecessary costs, energy consumptions as well as to conserve energy.

Evaluations and comparative analysis of operational states and scenarios were based on the water to power and power to water ratios. The obtained results indicate that optimal production operations strategies depend on the water to power or power to ratio targets. If a plant is designed to achieve a specific water to power or power to water ratio then process parameters must be optimized accordingly and an opera­tional strategy drafted to achieve the target water to power or power to water ratio. This is important since operational practice may deviate plant performance away from optimal performance. Although this approach is desirable, it should be noted that costs have an influence on the implemented plant configuration. Top brine tem­perature has also been identified as one of the limiting factors in reducing energy consumption in the desalination units. For the case study plant configuration, this limitation can be addressed through retrofits or plant re-designs to incorporate other issues such as new and/or improved seawater pre-treatment. Based on the investiga­tions recorded in this study, the following future work is recommended:

a. To carry out a detailed parametric study using process simulation method in order to appraise the physical behavior of dual purpose power and water produc­tion plants

b. To carry out a detailed thermodynamics and in-depth thermo-economic analy­sis of different configurations of power/water ratios in dual purpose power and water production plants

c. To develop an integrated value optimization framework for the production – distribution system (production and distribution) systems in order to leverage improvements in operating efficiencies with an added advantage of reducing the per unit cost of power and water production

C. Wangnai (H) ■ P. Kullavanijaya

Pilot Plant Development and Training Institute, King Mongkut’s University of Technology Thonburi (Bang Khun Thian), 49 Soi Thian Thale 25, Tha Kham,

Bang Khun Thian, Bangkok 10150 Thailand e-mail: chinnapong@pdti. kmutt. ac. th

S. Pitayarangsarit

TCM Environment Co., Ltd., 1 Moo 10, Soi Watmahawong, Samrong,

Phrapradaeng, Samutprakarn 10130 Thailand

[2] Dincer et al. (eds.), Progress in Sustainable Energy Technologies: 671

Generating Renewable Energy, DOI 10.1007/978-3-319-07896-0_42,

© Springer International Publishing Switzerland 2014

[3] H <27: no discomfort; 27 < H < 30 noticeable discomfort; 30 <H<40 evident discomfort; 40 < H < 55 dangerous discomfort; H > 55 heat stroke probable.

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