Production of Water from the Air: The Environmental Sustainability of Air-conditioning Systems through a More Intelligent Use of Resources. The Advantages of an Integrated System

Abstract The possibility of extracting water from air is an activity that has been studied recently, especially with the purpose of producing it for emergencies or exceptional events, when drinking water is not temporarily available. Several mobile/transportable equipment have been designed in order to producing water from the air: they can be placed, if necessary, in appropriate locations where water is needed. Water extraction can be done with different technologies, one of which is represented by cooling water below the dew point, to cause condensation of the vapour content of the air. The system efficiency, normally calculated in standard conditions, should be tested in the climatic conditions in which it will be used, because water production varies significantly with temperature and air water vapour content. An interesting solution may be an equipment for water extraction that contemporarily uses the cooled air for refrigeration, which consists in a combined HVAC system for the dual purpose of water production and air-conditioning. A case study represented by this kind of HVAC system, for a hotel in a sub-tropical arid climate, is proposed in this paper, to demonstrate the advantages of this solution. To this aim, the comparison is made between a typical HVAC system and an integrated air conditioning system, optimized for water production from air, in order to highlight advantages and capabilities of the second one

Simultaneous Identification of Thermophysical and Moisture Transport Properties in Porous Insulating Materials

An inverse technique is applied to the simultaneous reconstruction of thermophysical and mass transfer properties of a porous insulating material subjected to a transient Thermal experiment. The identification of the temperature-dependent thermal conductivity and specific heat of the dry material and of the two mass diffusion coefficients related to the moisture content gradient and to the temperature gradient is obtained by the inverse solution of a simpli- fied heat and mass transfer model. The Kalman filter in the LKF (linearised Kalman filter) version is adopted as parameter estimator. The preliminary results, obtained with simulated experiments, show the feasibility of identifying all the unknown parameters, both heat and mass diffusion properties, by the use of thermal measurements only. Moreover, the potential improve- ment of the estimation process achievable with supplementary information on the moisture con- tent evolution is investigated. The measurement model has been enhanced to handle both the thermal and the moisture response of the specimen, and the quality of the moisture signal has been varied to discover the level of accuracy required to give a significant improvement to the estimation

Historical Heritage: from energy consumer to energy producer. The case study of the \u2018Albergo dei Poveri\u2019 of Genoa, Italy

The monumental complex of the \u2018Albergo dei Poveri\u2019 was built between the late Seventeenth century and the middle of the Nineteenth as a monumental structure for charitable purposes. The idea of the complex was based on the segregation of poor and diseased people, divided for sex, age, social status and physical health. The monumental complex occupies a total surface of about 60,000 square meters, and the green area behind the complex, Valletta San Nicola, about 25,000 square meters. The building was almost completely abandoned since more than a decade, hence a renewal project was defined in order to allow a complete use of the building as a university campus (pole for humanities). Given its size and location in the heart of the city, the building could represent in the future a great opportunity for urban renewal. According to that, the Rector assigned, in 2011, to the School od Specialization in Architectural and Landscape Heritage (director prof. Stefano F. Musso) the task of preliminary researches related to the building restoration and renovation. This paper is focused on the aspects concerning the relation between improvement of energy efficiency and conservation of historical and architectural values, as this balance is often considered in conflict. Main aim of the part of the research here described, and still in progress, is the definition, from a methodological and technical point of view, of feasibility studies in order to submit the historical monumental heritage in a process of "energy efficiency" and "smart grids" (the research is funded by a grant from Regione Liguria). Following this main objective, the work investigates the possibility to use the monumental complex and its site as an energy-producer, and not only an energy-consumer. In particular, a feasibility study has been prepared, according to the structural and constructive characteristics of the complex, to obtain an efficient use of energy resources. Supported by Ansaldo Energia, the researchers begun an analysis to determine the most appropriate solutions for energy production technology through co-generation and tri-generation with microturbines powered by gas. The paper deals with: the general master plan with new uses; energy demand; the results and the problems of calculation through current software for heating and cooling; the analysis of the electricity demand and the needs of domestic hot water; the definition of the most suitable intervention to improve thermal behavior of the architectural complex and to produce energy

Adaptive Correction of Dynamic Temperature Measurements to Improve Estimation of Thermophysical Properties

The influence of sensor dynamics on the estimation of thermophysical properties of materials in transient heat conduction experiments is investigated. The temperature measured by the sensor (subminiature sheathed thermocouple) is corrected by identifying, in the same experiment, as well as the thermophysical properties of the material, also the unknown coefficients appearing in the dynamic model of the sensor itself. This approach provides an auto-adaptive temperature correction which can be used to improve the accuracy of the estimated thermophys- ical properties and to give quantitative information on the behaviour of the sensor in a dynamic regime. Different kinds of sensor-material coupling are investigated and compared: ideal thermal contact; presence of a thin air gap with or without the application of a heat sink compound at the measurement junction. Several results are presented, both from numerical simulations and true experiments at atmospheric pressure. Moreover, first results concerning the dynamic behaviour of the thermocouple inserted in a porous insulating material below atmospheric pressure are also presented. Among the different dynamic models utilised for characterising the transient thermal behaviour of the sensor, the first-order differential system with constant coefficients is relatively simple to implement, efficient, stable, and recommended