Based on the fact that malignant cancerous lesions (neoplasms) develop high metabolism and use more blood supply than normal tissue, infrared thermography (IR) has become a reliable clinical technique used to indicate noninvasively the presence of cancerous diseases, e.g., skin and breast cancer. However, to diagnose cancerous diseases by IR, the technique requires procedures that explore the relationship between the neoplasm characteristics (size, blood perfusion rate and heat generated) and the resulting temperature distribution on the skin surface. In this research work the dual reciprocity boundary element method (DRBEM) has been coupled with the simulated annealing technique (SA) in a new inverse procedure, which coupled to the IR technique, is capable of estimating simultaneously geometrical and thermophysical parameters of the neoplasm. The method is of an evolutionary type, requiring random initial values for the unknown parameters and no calculations of sensitivities or search directions. In addition, the DRBEM does not require any re-meshing at each proposed solution to solve the bioheat model. The inverse procedure has been tested considering input data for simulated neoplasms of different sizes and positions in relation to the skin surface. The successful estimation of unknown neoplasm parameters validates the idea of using the SA technique and the DRBEM in the estimation of parameters. Other estimation techniques, based on genetic algorithms or sensitivity coefficients, have not been capable of obtaining a solution because the skin surface temperature difference is very small.

Flow maldistribution represents a problem of particular interest in the engineering field for several thermal systems. In flat plate solar collectors, the thermal efficiency strongly depends on the flow distribution through the riser tubes, where a uniform distribution causes a uniform temperature distribution and therefore a higher efficiency. In this work, a Computational Fluid Dynamics (CFD) numerical analysis has been carried out using the commercial software FLUENT^®, in order to determine the flow distribution, pressure drop and hence the thermal efficiency of a solar collector with distribution flow plates inside the manifolds. The obtained numerical solution for this type of thermal systems has been validated with experimental results available in literature for laminar and turbulent flow. Four distribution plate configurations were analyzed. Results show that using two distribution plates in each of both manifolds improves the flow uniformity up to 40% under the same operating conditions when distribution plates are not used. Besides, it is shown that there exists an increase in the overall pressure drop which is practically negligible for the tilt angles commonly employed in the installation of flat plate solar collectors in Mexico. The use of closed end distribution plates on the dividing and combining manifolds allows the thermal efficiency to become close to the ideal thermal efficiency which is obtained with a uniform flow distribution.

This work presents the main behaviors shown in the habits of consumers of domestic refrigerators, which influences the energy consumption of this appliance. This study is based on a series of surveys answered by 200 consumers from four cities in the State of Guanajuato, Mexico. The questions were arranged with the aim of evaluating the general characteristics and usage habits such as refrigerator age, door opening frequency, damper position, load of food supplies, external and internal cleaning habits, and nearby heat sources, among other things. The randomly interviewed consumers were individuals between 20 and 60 years of age, who were interviewed using handmade surveys by experts in the field of refrigeration. In some cases, photographic evidence was gathered from the consumers’ refrigerators to represent the typical usage habits. In general, the results show that better usage habits are necessary from an energy point of view. Most consumers agree with adopting best practices for using their refrigerator.

In this work, a numerical analysis of three different flat plate solar collectors was conducted using their entropy generation rates. Specifically, the Computational Fluid Dynamics (CFD) technique was used to compare the detailed performance of conventional and zigzag tube geometries of flat plate solar collectors (FPCs) in terms of their entropy generation rates. The effects of fluid viscosity, heat transfer, and heat loss of the flat plate solar collectors were considered for the local and global entropy generation rate analyses. Variations on the inlet volumetric flow rate of the FPCs from 1.0 to 9.0 L/min were simulated under the average solar radiation for one year in the state of Guanajuato, Mexico. The results illustrate and discuss the temperatures, pressures, and global entropy generation rates for volumetric flow variations. The velocity, temperature, and pressure distributions and the maps of the local entropy generation rates inside the collectors are presented and analyzed for the case with a flow rate of 3.0 L/min. These results demonstrate that the zigzag geometries achieved higher outlet temperatures and greater entropy generation rates than the conventional geometry for all the volumetric flow rates considered.

In this chapter, an exergy analysis applied to a solid oxide fuel cell (SOFC)/vapor adsorption refrigeration (VAR) system is presented. The influences of four significant parameters (current density, inlet fuel temperature, fuel utilization and steam-to-carbon ratio) on the exergy efficiency of both the SOFC stack and the SOFC-VAR system are investigated. In order to do so, a mathematical model is constructed in Engineering Equation Solver (EES) software to generate the simulations. The analysis shows that the calculated exergy efficiency is around 8% lower than the energy efficiency for both cases. Moreover, it is found that most of the causes of irreversibilities in the system are due to electronic and ionic conduction in the components. It is also shown that the exergy efficiency is substantially sensitive to fuel inlet temperature, which is evidenced by a bending-over behavior. Finally, in accordance with the calculated efficiency defects, the main exergy destructions are present in the heat exchangers, the SOFC, the afterburner and the generator.