Francisco Javier Rey Martínez

Design and experimental study of a mixed energy recovery system, heat pipes and indirect evaporative equipment for air conditioning

Current difficulties surrounding air conditioning systems involve an increase in input air aimed at improving indoor air quality (IAQ), the financial costs arising from energy consumption and external environmental impact, linked to the greenhouse effect (GWP) and the destruction of the ozone layer (ODP). One alternative technique which offers an adequate combination of IAQ and acceptable energy saving is the introduction of energy recovery systems using air extracted from air-conditioned premises. We have designed a mixed air-energy recovery system, consisting of two heat pipes and indirect evaporative recuperators. The experimental set-up used is described and the proposed energy recovery system is characterised. A staggered set-up has been chosen for the input air pipe and a parallel one for the extracted air for variable recirculation. By means of the trace gas method and photoacoustic spectroscopy (PAS) the amount of exfiltrated flow in the installation is measured. The energy characterisation of the mixed energy recovery system was performed by means of the experimental design technique. An analysis was carried out of the influence of factors such as temperature, flow, relative humidity, water flow, etc. on the basic characteristics defined by the mixed system: heat flow, heat efficiency and COP.

Indoor air quality and thermal comfort evaluation in a Spanish modern low-energy office with thermally activated building systems

In the current context of a world energy situation that demands high-quality indoor environments compatible with rational energy use, the purpose of this work is to present a successful case study of a comfortable low-energy office building in Madrid, Spain. An exhaustive indoor air quality and thermal comfort field measurement survey was carried out during the summer period. The main global and local thermal comfort parameters in several workplaces, as well as CO2 concentration in supply air, exhaust air, and occupied space, were registered. Correct operation of the demand-controlled ventilation system and air distribution is observed. Also, thermally activated building systems and shading design make it possible to get high levels of indoor thermal comfort, as derived from measurements. This proves that the integration of novel energy-efficient concepts in office building design can not only contribute to a minimization of the energy use but can simultaneously favor the achievement of high indoor environmental quality.

Asset and Operational Energy Performance Rating of a Modern Apartment in Malta

This paper aims to evaluate the asset and operational energy performance rating of a modern apartment in Malta, by comparing modelling results of DesignBuilder-EnergyPlus and the Energy Performance Rating of Dwellings Malta (EPRDM) software, to actual energy consumption of the apartment. Results showed that EPRDM results compared favourably with the DesignBuilder results, although, the latter one showed higher energy consumption for cooling. This is attributed to the fact that EnergyPlus considers the hottest week in the sizing of cooling systems and the simulation is carried out dynamically for every hour of the day. Actual energy consumption for heating and cooling is generally lower than modelled results, which augurs well for the overall energy consumption in Maltese buildings. The thermal mass of Maltese buildings plays an important role in reducing peak loads.