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Abstract A new formulation for the evaporation, flashing, condensation processes taking place in the effects of thermal desalination systems which simulates the operation of both forward and parallel/cross configurations is coupled with an exergo-economic model based on the SPECO method. The thermo-economic model uses accurate properties for the seawater, brine, pure water and vapour and is solved with an equation solver which does not require the development of a specific solution algorithm as in most previous studies. This flexible model is used to analyze the influence of the number of effects N and the temperature difference ΔT e between effects on the technical and economic performance of multi-effect desalination systems with ejector vapour compression. In particular, it is shown that the performance calculated by an earlier black-box approach is not attainable by technically and economically realistic systems. It is also shown that for each feed configuration and a given number of effects there exists an optimum value of ΔT e which minimizes the cost of the produced potable water. This last result forms the basis of a procedure that combines black-box results with the optimum value of ΔT e and can be used to select the appropriate system for any specific application.

Abstract A new formulation for the evaporation, flashing, condensation processes taking place in the effects of thermal desalination systems which simulates the operation of both forward and parallel/cross configurations is coupled with an exergo-economic model based on the SPECO method. The thermo-economic model uses accurate properties for the seawater, brine, pure water and vapour and is solved with an equation solver which does not require the development of a specific solution algorithm as in most previous studies. This flexible model is used to analyze the influence of the number of effects N and the temperature difference ΔT e between effects on the technical and economic performance of multi-effect desalination systems with ejector vapour compression. In particular, it is shown that the performance calculated by an earlier black-box approach is not attainable by technically and economically realistic systems. It is also shown that for each feed configuration and a given number of effects there exists an optimum value of ΔT e which minimizes the cost of the produced potable water. This last result forms the basis of a procedure that combines black-box results with the optimum value of ΔT e and can be used to select the appropriate system for any specific application.

Abstract In this paper, energy and exergy analyses of the geothermal-based hydrogen production via thermochemical water decomposition using a new, four-step copper–chlorine (Cu–Cl) cycle are conducted, and the respective cycle energy and exergy efficiencies are examined. Also, a parametric study is performed to investigate how each step of the cycle and its overall cycle performance are affected by reference environment temperatures, reaction temperatures, as well as energy efficiency of the geothermal power plant itself. As a result, overall energy and exergy efficiencies of the cycle are found to be 21.67% and 19.35%, respectively, for a reference case.

Abstract In this paper, energy and exergy analyses of the geothermal-based hydrogen production via thermochemical water decomposition using a new, four-step copper–chlorine (Cu–Cl) cycle are conducted, and the respective cycle energy and exergy efficiencies are examined. Also, a parametric study is performed to investigate how each step of the cycle and its overall cycle performance are affected by reference environment temperatures, reaction temperatures, as well as energy efficiency of the geothermal power plant itself. As a result, overall energy and exergy efficiencies of the cycle are found to be 21.67% and 19.35%, respectively, for a reference case.

This paper presents different Maximum Power Point Tracking (MPPT) methods belonging to different classes as well as two overviews. The first was about the procedures used in the test and evaluation of MPPTs. The second is an overview of Fuzzy Logic Controller (FLC) MPPTs and improved MPPTs. Conventional MPPTs such as Perturb and Observe (P&O), Hill Climbing (HC) and Incremental Conductance (InCond); Improved MPPTs (are the modified versions of conventional MPPTs) such as Improved Incremental Conductance (Improved-InCond) and intelligent MPPTs such as FLC have been implemented and tested under two different levels of irradiance and temperature. A detailed description about the hardware and software implementation platforms (designed and built in our laboratory) is provided. Based on measured data, the MPPTs under consideration have been evaluated and compared in terms of different criteria, showing the advantages and disadvantages of each one. The comparison results showed that Improved-InCond gives a fast convergence to the MPP(Maximum Power Point). Whereas, FLC is able to adapt to the variation of irradiance and temperature levels. Thereby, a good performance is obtained wherein the MPP is reached in a short time as well as the power ripples are very small.

This paper presents different Maximum Power Point Tracking (MPPT) methods belonging to different classes as well as two overviews. The first was about the procedures used in the test and evaluation of MPPTs. The second is an overview of Fuzzy Logic Controller (FLC) MPPTs and improved MPPTs. Conventional MPPTs such as Perturb and Observe (P&O), Hill Climbing (HC) and Incremental Conductance (InCond); Improved MPPTs (are the modified versions of conventional MPPTs) such as Improved Incremental Conductance (Improved-InCond) and intelligent MPPTs such as FLC have been implemented and tested under two different levels of irradiance and temperature. A detailed description about the hardware and software implementation platforms (designed and built in our laboratory) is provided. Based on measured data, the MPPTs under consideration have been evaluated and compared in terms of different criteria, showing the advantages and disadvantages of each one. The comparison results showed that Improved-InCond gives a fast convergence to the MPP(Maximum Power Point). Whereas, FLC is able to adapt to the variation of irradiance and temperature levels. Thereby, a good performance is obtained wherein the MPP is reached in a short time as well as the power ripples are very small.

Abstract In this paper a stochastic robust optimization problem of residential micro-grid energy management is presented. Combined cooling, heating and electricity technology (CCHP) is introduced to satisfy various energy demands. Two-stage programming is utilized to find the optimal installed capacity investment and operation control of CCHP (combined cooling heating and power). Moreover, interval programming and robust stochastic optimization methods are exploited to gain interval robust solutions under different robustness levels which are feasible for uncertain data. The obtained results can help micro-grid managers minimizing the investment and operation cost with lower system failure risk when facing fluctuant energy market and uncertain technology parameters. The different robustness levels reflect the risk preference of micro-grid manager. The proposed approach is applied to residential area energy management in North China. Detailed computational results under different robustness level are presented and analyzed for providing investment decision and operation strategies.

Abstract In this paper a stochastic robust optimization problem of residential micro-grid energy management is presented. Combined cooling, heating and electricity technology (CCHP) is introduced to satisfy various energy demands. Two-stage programming is utilized to find the optimal installed capacity investment and operation control of CCHP (combined cooling heating and power). Moreover, interval programming and robust stochastic optimization methods are exploited to gain interval robust solutions under different robustness levels which are feasible for uncertain data. The obtained results can help micro-grid managers minimizing the investment and operation cost with lower system failure risk when facing fluctuant energy market and uncertain technology parameters. The different robustness levels reflect the risk preference of micro-grid manager. The proposed approach is applied to residential area energy management in North China. Detailed computational results under different robustness level are presented and analyzed for providing investment decision and operation strategies.