Energy performance assessment of HVAC systems by inspection and monitoring

The paper discusses the collection and processing of energy performance data as part of the inspection of HVAC systems, aimed at identifying technically feasible and cost-effective Energy Conservation Opportunities (ECO), as required by EPBD. Case studies developed by the HARMONAC project have shown that low-cost or no-cost ECO's - mostly related to system operation and management - can be identified with an effective system monitoring. Building Management Systems (BMS) may be a powerful tool for this task, provided their HW and SW architecture is designed with adequate attention to energy monitoring. Dedicated instrumentation - such as electricity meters and temperature loggers - may also be employed as an alternative / integration to BMS monitoring. The paper also discusses the application of data analysis tools - such as "carpet plots" and "energy signatures" - to the identification of component malfunctioning, control problems, inadequate maintenance, or system schedule optimization, and to the evaluation of achieved energy saving

Full characterization of the quantum linear-zigzag transition in atomic chains

A string of repulsively interacting particles exhibits a phase transition to a zigzag structure, by reducing the transverse trap potential or the interparticle distance. The transition is driven by transverse, short wavelength vibrational modes. Based on the emergent symmetry Z_2 it has been argued that this instability is a quantum phase transition, which can be mapped to an Ising model in transverse field. We perform an extensive Density Matrix Renormalization Group analysis of the behaviour at criticality and evaluate the critical exponents and the central charge with high precision. We thus provide strong numerical evidence confirming that the quantum linear-zigzag transition belongs to the critical Ising model universality class. These results show that structural instabilities of one-dimensional interacting atomic arrays can simulate quantum critical phenomena typical of ferromagnetic systems.Comment: 5 pages, 4 figure

Selection of procedures for air conditioning audit and definition of the associated training package

In the current transformation of the air conditioning (AC) market, important efforts should be achieved to improve the energy efficiency of these systems all along their life cycle. To detect and define the performance degradation of these facilities, a global approach has to be developed and the complexity of the systems implies the creation of reliable and efficient audit procedures and methods. In the AUDITAC project, we will describe the features of the two levels audit methods; pre-audit (or walk-through) and (detailed) audit. In order to support the harmonisation of the implementation of the AC systems inspection, starting from the inspection schemes already on the market, we assessed their effectiveness and establish a link with the operation and maintenance practices. The decision for renovation will be developed in its aspects of energy savings and economic feasibility. In order to disseminate and involve easily the AC actors in the audit methods, we have developed a basic training package (TP) about auditing AC facilities. This tool has been created to prepare and introduce air conditioning actors (energy managers, facilities owners, technicians related to AC etc…) to the compulsory inspection and to disseminate the advantages and opportunities that the subsequent audit can give. The audit approach is globally explained in the TP from cooling production to distribution, operation and maintenance and finally control strategies. Quantitative indicators for best practices and improvement examples are showed to support decision of renovation. Basically, the TP has been designed for a public with an educational level of post-high school and can be used in different scenarios (students with HVAC class, inspection technicians, energy managers’ information etc…)

Nonequilibrium quantum thermodynamics in Coulomb crystals

We present an in-depth study of the nonequilibrium statistics of the irreversible work produced during sudden quenches in proximity to the structural linear-zigzag transition of ion Coulomb crystals in 1+1 dimensions. By employing both an analytical approach based on a harmonic expansion and numerical simulations, we show the divergence of the average irreversible work in proximity to the transition. We show that the nonanalytic behavior of the work fluctuations can be characterized in terms of the critical exponents of the quantum Ising chain. Due to the technological advancements in trapped-ion experiments, our results can be readily verified

FLUIDODINAMICA DEI PROCESSI DI CONDENSAZIONE IN DEFLUSSO CONTROCORRENTE

Politecnico di Torino, PT DE IN 14

STUDIO DI VARIABILI CLIMATICHE PER LA VALUTAZIONE DI IMPATTO AMBIENTALE E L'ANALISI DELLE PRESTAZIONI ENERGETICHE DEGLI EDIFICI

Tesi di Dottorato di Ricerca in Fisiaca Tecnic

FLUIDODINAMICA DEI PROCESSI DI CONDENSAZIONE IN DEFLUSSO CONTROCORRENTE

Politecnico di Torino, PT DE IN 14