Analysis of the thermal performance of heat exchangers for active chilled beam units

Coils used in active chilled beams (ACB) have some distinctive features compared to conventional coils used in fan-coil units. On the air side, the flow rate of induced air is limited and air velocities are thus much lower than those prevailing in fan-coils. Consequently, most of the correlations available in the open literature to calculate the convection coefficient on the air side are out of range when applied to ACB coils. In addition, the nature of the induction process causes some degree of non-uniformity in the air distribution over the coil. On the liquid side, circuitry can also be distinctive due to space constrains or functional requirements. Some commercial products use one circuit arrangements (all tubes connected in series) with different possible flow paths; two or more circuit schemes are also frequent. In this paper, ongoing research on active chilled beam modeling is presented. A generic numerical model of plate fin-and-tube heat exchanger is briefly described along with a test bench in which several ACB units have been tested. Experimental data for an example coil is used along with the coil model to determine a correlation for the air-side heat transfer. The calibrated numerical model is then used to simulate the coilUniversidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

The Work of Art in the Age of Digital Fragility

Impermanence and fragility have become the defining conditions of the digital age. Technologies that were ubiquitous barely a decade ago, like floppy disks, now look like archaeological relics. It takes only a few years, if not months, before software environments are replaced by newer versions, often with limited backward compatibility. At the same time, digital technologies rely on hardware that has short life expectancy. The radical obsolescence of this new digital register raises a number of important questions. How are we going to prevent the fragile memories of contemporary digital cultures from receding into oblivion? This essay answers this question by looking at one of the institutions in which the problems associated with digital fragility are most especially felt, the Museum of Modern Art (MoMA), and by exploring the ontological displacements that digital objects are operating at the heart of the museum

Climate control of an outdoor classroom using renewable energy

Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Simulation of a solar funnel cooker using MATLAB

A software for the calculation of the radiation heat transfer in solar funnel cookers by means of the radiosity method has been developed in Matlab. The software has been used to study a folding solar cooker. The cooker geometry is discretized using a triangular mesh where a piecewise constant approximation is assumed for the radiosity function. Form factors, including self-occlusions, are calculated by properly refining the triangular mesh. The concentration factor of the solar cooker is estimated as a function of its position and orientation with respect to that of the Sun.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Saw-Tooth Cardiomyopathy: Try Not to Stumble Twice Over the Same Stone.

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Simulation of a solar assisted counterflow tunnel dehydrator

A widely used class of vegetable dehydration systems are the “tunnel-and-truck” dehydrators, where the prepared material lies over horizontal trays stored in trucks which move discontinuously in opposite direction of the air flow. This way the driest product is facing the inlet hot and dry air blowed to the system. When product of one truck is ready, is removed from the tunnel leaving space for advance the remaining truck one place forward. This way, a new truck full of wet product can be inserted at the end of the tunnel. The hermal energy required for the process can be supplied by several sources including gas, biomass, solar energy or a combination of them. Solar energy is for free but reaches the Earth with quite a low flux and a strongly fluctuating rate. This imposes the need of special designs and control strategies. This paper presents a study based on simulation models of the dehydrator and the solar thermal system. The dehydrator simulation model is tuned to match experimental data from a particular prototype based on fossil fuel. A solar system simulation model is then applied to the analysis of different design options.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech