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Thermal balance of steam boilers can be done by two ways, the direct or indirect method; the direct method is not accurate. The reason why it is not accurate is that some operating parameters of biomass boilers cannot be obtained by direct measurements, like the measurement of fuel flow. These facts make it difficult to apply the direct method in the heat balance and force to use indirect one to determine these parameters and the boiler efficiency; hence, the indirect method is generally used for heat balance. Indirect method provides more accurate values and additionally, quantifies each of the energy losses, allowing to determinate causes of low efficiency of the equipment. Large amount of data involved implies the use of more affective calculation means; being iterative, assumed values for fuel flow must be compared with a value calculated until both match. In this work, the indirect method has been programmed in MATLAB; and for the preliminary fuel flow evaluation an optimization method could be used to prevent having to assume a value. Calculation details and a MATLAB algorithm are also presented.

Irrigation is responsible for approximately 70% of the world’s freshwater consumption and is one of the key factors behind the growing global water scarcity. Irrigation systems and techniques are extremely differentiated and complex. In this context, tools of computational fluid dynamics (CFD) earn relevance, allowing a detailed analysis and forecast of hydraulic behavior in different situations. In order to evaluate flow details in a dripper, this study applies CFD tools to study a drip irrigation system from three different perspectives: (i) analysis of the complete system of piping and dripper; (ii) analysis of only the isolated dripper expanded and biphasic model; and (iii) analysis of the isolated dripper operating in transient regime. Modeling results allowed a full understanding about speed fields, pressure and friction loss along the geometry. The drop formation process in the dripper output could be displayed in detail, and the obtained dripper flow output was close to the nominal value of manufacturer, in the case of the isolated dripper analysis. Although a comparison with results from experiments was not possible at the time, based on manufacturers’ catalogs, results proved satisfactory, leading to successful simulations.