M. Domínguez

Testing the computer assisted solution of the electrical analogy in a heat transfer process with a phase change which has an analytical solution

A new method has been developed for the computer assisted solution of electrical analogies. The method, relatively simple in comparison with other methods, allows the study of heat transfer problems, including the change of phase. The aim of this work has been to apply this technique to the study of a heat transfer problem with change of phase, which has an analytical solution, in order to test its validity. The results obtained by both methods, analytical and analogical, are compared, and they are observed to agree satisfactorily. It makes it possible to establish that the technique developed is suitable for the study of processes with a phase change present.

Aprovechamiento de los Materiales de Cambio de Fase (PCM) en la Climatización

The possibilities that present phase change materials in the heat storage of big quantities of heat in reduced spaces in the field of the air conditioning are analyzed. Several installations of climatization are described where phase change materials (PCM) have been satisfactorily incorporated and diverse types of installations including systems of thermal energy production as well as those that take advantage of free cooling in direct form, or indirect form by means of evaporative systems, or those that take advantage of residual heats or cogeneration. Considering the multiple advantages of the PCM it is concluded that they will be widely used in the future.

A new way to predict thermal histories in multidimensional heat conduction: The z-transfer function method

Abstract The z-transfer function is presented as a simple and precise method for the prediction of time-temperature curves in solids of constant thermo-physical properties which undergo multidimensional heat conduction. This method is specially suited for systems with irregular geometries and/or nonstandard boundary conditions, where calculations generally involve the use of numerical methods with great need for computer time and memory.

Free Cooling with Phase Change Materials (PCM)

Phase change materials (PCM) are described along with some of their advantages in air conditioning installations, particularly with regard to taking advantage of the free cooling that can be obtained from the ambient air, by using either sensible heat or evaporation. Certain installations are described and the paper concludes by stating that PCMs in microcapsules will facilitate the use of free cooling.