1,721,042 research outputs found
The energy cost of the indoor climate quality in museums: the "green meuseums" challenge
No full textIndoor climatic control is a crucial aspect for artefacts conservation in museum environments to prevent damages. Last years development of technologies and equipments aimed at continuous monitoring the indoor environmental parameters (temperature, relative humidity, air speed, lighting, air pollutants, etc.) allowed the collection, elaboration and analysis of indoor environmental data in order to avoid any deterioration processes on works of art: preventive control programmes are nowadays widely applied in museums. Anyway, what is the energy price we have to pay to maintain a strict mechanical indoor climatic control in museum? Is it really necessary to keep the indoor climatic parameters within a narrow range? These are key questions because also museums have to face with: - energy issues, where the goal is a rational use of energy sources and an increasing application of renewable sources - environmental issues, where the goal is a reduction of CO2 emission - economical issues, where the goal is to reduce the impact of energy costs. Nevertheless, in museums these goals have to be achieved without compromising preservation aspects: that's the way to follow for a new target for museums, the "green museum". The study will present investigations aimed at highlighting the relationship between indoor environmental quality level in museums, as defined by ASHRAE Applications Handbook [2] and Italian Standard UNI 10829/1999 [1], and the energy and environmental costs necessary to provide the required indoor environmental quality level, analysing different thermo-physical characteristics of the building envelope and different HVAC system solution
Indoor climatic control level, energy demand and CO2 emissions in museum environments
No full textAny work of art, either displayed in a museum or as an integral part of a monumental historical building, needs a controlled microclimate, mostly in terms of temperature and relative humidity, for its preservation. The thermo-hygrometric conditions surrounding the artifacts, and in particular their rapid changes over time, are critical for preservation. Therefore, environmental monitoring has gained more and more importance with regard to the techniques of data survey, processing, and analysis. By applying a long-term approach, a study was developed in order to analyze the microclimate quality of the indoor environment and the corresponding energy demand and CO2 emissions during the operational period of a museum case study, through energy simulation performed by a building energy simulation software. The numerical study aimed at examining the existing relationships among the microclimate level requirements, the potential of the “building-plants system” control, energy consumptions and CO2 emissions has been carried out. The investigations are applied to different indoor climatic control levels suggested by the “ASHRAE classes”, and enables a better understanding of the factors influencing the thermo-hygrometric category of an environmen
Study of Techniques For Reliable Data Transmission In Wireless Sensor Networks
Full text linkThis thesis addresses the problem of traffic transfer in wireless sensor networks (WSN). In such networks, the foremost challenge in the design of data communication techniques is that the sensor's transceiver circuitry consumes the major portion of the available power. Thus, due to stringent limitations on the nodes' hardware and power resources in WSN, data transmission must be power-efficient in order to reduce the nodes' power consumption, and hence to maximize the network lifetime while satisfying the required data rate. The transmit power is itself under the influence of data rate and source-destination distance. Thanks to the dense deployment of nodes in WSN, multi-hop communication can be applied to mitigate the transmit power for sending bits of information, i.e., gathered data by the sensor nodes to the destination node (gateway) compared to single-hop scenarios. In our approach, we achieve a reasonable trade-off between power-efficiency and transmission data rate by devising cooperative communication strategies through which the network traffic (i.e. nodes' gathered information) is relayed hop-by-hop to the gateway. In such strategies, the sensor nodes serve as data originator as well as data router, and assist the data transfer from the sensors to the gateway. We develop several data transmission schemes, and we prove their capability in transmitting the data from the sensor nodes at the highest possible rates allowed by the network limitations. In particular, we consider that (i) network has linear or quasi-linear topology, (ii) nodes are equipped with half-duplex radios, implying that they cannot transmit and receive simultaneously, (iii) nodes transmit their traffic at the same average rate. We compute the average data rate corresponding to each proposed strategy. Next, we take an information-theoretic approach and derive an upper bound to the achievable rate of traffic transfer in the networks under consideration, and analyze its tightness. We show that our proposed strategies outperform the conventional multi-hop scheme, and their average achievable rate approaches the upper bound at low levels of signal to noise ratio
Verification of the impact of occupancy-related assumptions on the energy performance of an office building in different climates
No full textBuilding energy simulation is a commonly used method for predicting the energy performances of buildings. Simulation is adopted for its possibility to reproduce the physical behaviour of a building.
Nowadays, many simulation tools are available, but there are some drawbacks to their usage, i.e. there are no applications of building simulation which involve the usage of the building by its occupants. These tools rely on assumptions with regard to human behaviour, for example in the case of thermal load calculations. In building physics, behaviour research is mainly focused on control-oriented user behaviour, as the interaction between the occupants of a
building and its controls, like windows, lights and heating systems. This study focuses on the simulation of human activity behaviour in office buildings;aiming at verifying the impact of window opening assumptions on building energy performances in different climates
A methodology for microclimatic quality evaluation in museums: Application to a temporary exhibit
No full textEvery single artefact, either exhibited in a museum or as an integral part of a historical building, needs a controlled microclimate in order to be preserved. Since a monitoring program can support decisions and actions aimed at preventing the deterioration of vulnerable objects, the need to observe the environmental parameter status and variations over time is of primary importance in museums. In this paper a methodology to evaluate the microclimatic quality in museums is presented, in accordance with the Italian Standard UNI 10829 focused on the statistical analysis of the data. The methodology, based on a medium/long-term monitoring aims at determining a synthetic index to judge the microclimate quality related to the requirements to avoid preservation risks. The measured data are compared with the required values for artefact preservation. The thermal quality is evaluated by the ‘‘performance index'', which expresses the percentage of time in which the required parameters do not match. The procedure is applied for the thermal qualification of a temporary exhibi
Behavior change - occupants' interaction with building automation, controls and technical building management
No full textProgettare edifici resilienti al comportamento degli utenti
No full textAllo stato attuale, la previsione dei consumi reali di un edificio risente di una poco accurata descrizione delle variabili influenzanti l'uso dell'energia, per lo più legate all'utilizzo dell'edificio, tra cui spicca il comportamento degli utenti. Lo scopo di questa ricerca è valutare la capacità dell' involucro di limitare l'influenza degli utenti sui consumi energetici di un edificio, ovvero di determinare il suo grado di resilienza per differenti ipotesi di involucro. L'analisi è stata svolta su un edificio per uffici di riferimento servendosi di un software di simulazione energetica dinamica che supporta modelli comportamentali stocastici, focalizzandosi sulle azioni su finestre e schermature mobili. Sono state simulate cinque zone termiche con caratteristiche ed esposizioni differenti, nei climi di Stoccolma (nordico), Francoforte (continentale) ed Atene (mediterraneo). Dai risultati è emerso che la presenza combinata di involucro massivo, ridotta superficie vetrata e schermature fisse comporta sia i minori consumi per riscaldamento e raffrescamento, sia la maggior resilienza dell'edificio rispetto al comportamento dell'utente. Accanto agli indirizzi progettuali, lo studio dimostra le potenzialità dei software di simulazione quali strumenti per una progettazione consapevole: nel caso specifico la descrizione realistica del comportamento degli utenti ha consentito di valutare la capacità di un edificio di mantenere prestazioni costanti nonostante cambi di utenz
Validation of Occupants’ Behaviour Models for Indoor Quality Parameter and Energy Consumption Prediction
Full text linkOccupants’ behaviour related to building control system plays a significant role to achieve thermal comfort and air quality in naturally-ventilated buildings. Generally, the published models of occupant's behavior are not validated, meaning that the predictive power has not yet been tested. For this reason, the validation of occupant's behavioral models is an issue that is gaining importance.In this paper validation was carried out through dynamic Building Energy Performance simulation (BEPS); behavioral models of windows opening and thermostats set-point published in literature were implemented in a dynamic BEPS software and the obtained results in terms of temperature, relative humidity and CO2 concentration were compared to real measurements. Through this comparison it will be possible to verify the accuracy of the implemented behavioral models.The models were able to reproduce the general tendencies in the measured temperatures but the simulation results diverged from the measured CO2 concentrations and relative humidity
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