Néstor Fonseca Diaz

Experimental study of the energy and thermal comfort performance of chilled ceiling panels

This article presents the results of a study performed to obtain the main operating characteristics of a chilled heating ceiling system in cooling mode. An experimental analysis of the cooling ceiling system in a climatic chamber is presented in order to evaluate the behavior of its cooling capacity, pressure drop, and thermal comfort. The purpose of the present study is to evaluate the influence of certain factors, such as the ventilation strategy, water mass flow rate, water temperature, and load distribution, on the global behavior and performance of the system. The results show that a high cooling load can be removed, and also a high degree of thermal comfort can be achieved, with this kind of system. However, strong influences of the heat sources distribution and surface temperatures inside the room on its performance are observed, especially for thermal comfort conditions (asymmetric thermal radiation).

Estudio del sistemas de regulación de ventilación en un edificios como parte de la auditoria energética de sistemas HVAC

This article presents the results of the experiment al study of a ventilation system in a commercial building. The aim is to show the ex perimental results of a typical commissioning procedure of ventilation syst ems. The principal alternatives of economy in regulation on the air su pply, renovation and extraction circuits are shown.

MODELAMIENTO SIMPLIFICADO DE UN EDIFICIO DE UNA ZONA MEDIANTE UNA RED R-C PARA APLICACIONES HVAC.

This article presents the results of a study perfor med to develop a computational model of a mono-zone building. The model considers the latent and sensible heat exchange between an air space (mono-zone) connected to a detailed lumped dynamic model of the building walls and windows (R- C network).This model can be used in the frame of a pre-audit procedure, wher e an experimental identification of the building heating & cooling de mands is usually not envisaged (heat/cool counters are not often install ed in buildings). But a calculation of theoretical demands and correspondin g energy consumptions is required at the start of a feasibility calculation and of a detailed study of retrofit opportunities.

ANÁLISIS EXPERIMENTAL Y MODELADO DE COMPRESORES A ESPIRAL EN APLICACIONES HVAC/R

This article presents the results of the experiment al study of scroll compressors . The orders of magnitude of the isentropic and volum etric efficiencies of these compressors are studied. For the modeling a semi-em pirical approach is used, where some model parameters are defined from labora tory measurements or catalogues data. Some examples of identification of parameters and simulation are presented. The modeled shows the importance of considers the physical phenomena that happen inside of the machine to repr esent in a better form their behavior. The modeling showed is modular; therefore it can be used in a more complex system: as it is the case of a heat pump, a n air conditioning or cooling system.

UTILIZACIÓN DE DATOS DE CATÁLOGO PARA EL MODELADO DE EQUIPOS HVAC/R

This article presents the results of a study perfor med to develop a computational model of HVAC/R equipment that can be used from man ufacturer catalog data. As example of the model in this article the model o f a fan, cooling coil and a condensation boiler are presented. It is observed t hat in most of the case the data information is not sufficient to develop a goo d representation of its behavior using of the model.

Estudio experimental del proceso de acondicionamiento de aire mediante sales disecantes en aplicaciones HVAC/R.

Este articulo presenta los resultados del estudio experimental realizado para evaluar el proceso de tratamiento de aire mediante sales disecantes. Se estudia el proceso de secado del aire mediante disecantes liquido en una unidad de acondicionamiento de concepcion clasica usada como banco de ensayos. Las dificultades encontradas durante la utilizacion del sistema con sales disecantes son descritas aqui como las mejoras del banco de ensayo necesarias para incrementar el rendimiento del proceso.

Estudio experimental de sistemas de ventilación en edificios como parte de la auditoria energética de sistemas hvac..

En este articulo se presentan los resultados de un estudio experimental realizado para evaluar el estado de funcionamiento del sistema de ventilacion en un edificio de tipo comercial. El problema se debe a que los ocupantes del edificioconsideran que la renovacion de aire es insuficiente y no permite asegurar las condiciones de confort en las oficinas. El objetivo de este estudio es dar algunas recomendaciones practicas sobre “Commissioning” de sistemas de distribucion de aire. Esta informacion y los procedimientos utilizados son de gran utilidad en la auditoria energetica de sistemas HVAC.

Auditoria energética de un sistema de enfriamiento tipo techo en aplicaciones HVAC/R.

El sistema de enfriamiento tipo techo de un edificio de tipo comercial en Bruselas Belgica es experimentalmente evaluado por medio de un procedimiento de ensayo y un modelo de calculo detallado del sistema. Este modelo es usado en terreno como herramienta de diagnostico en procesos de auditoria energetica (comissioning) para determinar el estado de funcionamiento de los principales parametros de operacion sistemas. El origen del problema: el sobrecalentamiento en algunas zonas del edificio debido a la enorme superficie vidriada. Los sistemas considerados para el commissioning son la fachada, el sistema de ventilacion y el sistema de enfriamiento tipo techo. Se evalua la interaccion y funcionamiento individual de cada uno de estos sistemas.

Thermal Model and Experimental Validation of Humidifier Systems as Commissioning Tools in HVAC Systems

This paper presents the results of an experimental study performed to obtain a simplified model applicable to two adiabatic humidification systems: wetted wires and centrifugal atomizing. The aims of this study are to provide a model to be used in situ as a diagnosis tool in the commissioning of air-conditioning systems, and to develop a comparison between “wet” and “therma” effectiveness methodologies that also can be useful for the commissioning process. The model is able to predict the exhaust dry-air temperature, exhaust humidity ratio, and the humidifier effectiveness by using as inputs the supply-air temperature and relative humidity as well as the air and water mass flow rates. Simplicity and accuracy are the crucial factors. A series of tests are performed in order to validate the model.