Toward to the control system of mechanical draft cooling tower of film type

For changing atmospheric conditions the mathematical model of a control system of a mechanical draft cooling tower has been developed. The model includes a heat and mass transfer processes between water films and turbulent damp air flow at quasi-state approximation. Various regimes of cooling tower performance are compared and the optimization method is proposed.     

Optimal control of flow in low temperature solar heat collector

Solar energy collection plants with uniform flat plate collectors are classified according to the mode of operation and the type of performance criterion. The problem of optimal control of flow through the collector is formulated under simplifying assumptions and conditions for the existence of an optimal control of the system are stated for certain elements of the above classification. A numerical process for the optimal solution is described and an example of solution given. A simple control policy is given, applicable to those elements of the above classification where a continuous solution of the problem does not exist. This policy consists of alternate switching between zero and maximum available flow. A direction for further research into some aspects of the optimal control problem is suggested.     

Correlation analysis of geothermal data in North America

Correlation studies of the geothermal parameters have been carried out for Michigan Basin and the results are interpreted with the help of observed relations between heat flow, geological age and crustal thickness for North America. Heat flow and geothermal gradient are found to decrease with thermal conductivity, while they are positively correlated with each other, supporting the earlier findings of Negi et al. (1974). It is noted that, to some extent, these associations can be explained with the help of variations in crustal thickness.     

Autothermal sorption-enhanced steam reforming of bio-oil/biogas mixture and energy generation by fuel cells: Concept analysis and process simulation

A concept of sorption-enhanced steam reforming of bio-oil/biogas for electricity and heat generation by phosphoric acid fuel cells is investigated. The process is modeled using SIMSCI Pro II process simulator. Sorptive removal of the carbon dioxide from the reaction site results in low CO and _CO2${\mathrm{CO}}_2$ concentrations (<1%$<1\%$) in the reformate, as a result it can be used in the phosphoric acid fuel cell without any further fuel cleanup. High hydrogen concentration and calorific value of the reformate enable the operation of the fuel cell at a high-efficiency mode despite of the high carbon/hydrogen ratio of the bio-fuel. Addition of biogas to the reformer enables autothermal operation of the reformer, as well as significantly improves the efficiency of the process. The simulation shows that the overall efficiency of the proposed system is compatible with the efficiency of the system using “classical” steam reforming of the fuel. The process exhibits 6% lower electrical efficiency compared to the system utilizing natural gas, and 4.6% higher efficiency compared to a system using bio-oil as a fuel.     

H2 production from methane pyrolysis over commercial carbon catalysts: Kinetic and deactivation study

Hydrogen production from catalytic methane decomposition (DeCH₄) is a simple process to produce high purity hydrogen with no formation of carbon oxides (CO or CO₂). However, to completely avoid those emissions, the catalyst must not be regenerated. Therefore, it is necessary to use inexpensive catalysts, which show low deactivation during the process. Use of carbon materials as catalysts fulfils these requirements.     

Power output characteristics of a finitely segmented faraday mhd generator

Accounting for the effect of finite segmentation of electrodes as a reduction of both the electrical conductivity of the working fluid and the Hall parameter, we have derived expressions of power density for a finitely segmented Faraday MHD generator with and without considerable electrode voltage drop. While calculating the actual loading factor through the electrode voltage drop, the latter has been estimated in a finitely segmented Faraday MHD generator with and without ash in the combustion products. The results have been discussed and compared with earlier results where the considered effects are not taken into account. It is found that the effects of finite segmentation of electrodes and the electrode voltage drop modify the power output characteristics significantly.     

Optimisation of steam-based energy transport in distributed solar systems

This paper investigates the methodology for the systematic optimisation of a low-cost transport piping network for distributed solar systems. In order to determine the range of power sizes for which this form of energy transport is economical, equations are developed to yield optimum engineering design parameters for steam-based energy transport in pipelines. A computer software package has been developed which gives the most cost effective layout of optimum networks, size of each pipe/insulation, percentage of the maximum pressure drop to the inlet pressure (% Δp), and percentage of the cost of energy transportation to the energy collected (% cost). Power station sizes of up to 84 MW_e have been studied with collectors of area 300 m² each.