1,721,035 research outputs found
Treno e nave: opportunità di green logistics ai tempi del Covid
No full textLa crisi di questi mesi ha mostrato come si possa passare – nel giro di pochi giorni – da un
traffico congestionato a un azzeramento quasi totale con l’adozione di modelli di lavoro a
distanza, con visibile riduzione dell’inquinamento e, al contempo, ci ricorda l’enorme potere e la
grande responsabilità nei confronti dell’ambient
An integrated framework for energy performance improvement in manufacturing: From mapping to optimization
No full textEnergy performance improvement in manufacturing is hindered by the lack of information on energy use in production and by the predominant economic vision in the assessment of energy interventions. This paper proposes a framework that integrates energy performance mapping with energy systems optimization. The framework introduces a new dimension to energy performance mapping by tracing energy use along processing and energy conversion steps and revisits multi-criteria assessments by assigning penalties to the energy performance gap with best practice. The suitability of food manufacturing for the application of the framework is exemplified from both a top-down and bottom-up perspective. More than 80% reductions in purchased energy carriers and non-renewable energy sources are achieved in a representative process through interventions coupling sector-specific manufacturing knowledge and energy expertise. With regard to one of the interventions, the introduction of the penalty is shown to shift the optimal solution, yielding more than 25% reductions in energy consumption compared to a purely economic assessment. The proposed framework can help industrial stakeholders identify improvement opportunities and develop more sustainable energy systems in manufacturing. Its widespread use can encourage poor performing companies to align with best practice and virtuous companies to continuous innovation to maintain their competitive advantage
HVAC energy saving strategies for public buildings based on heat pumps and demand controlled ventilation
No full textThe paper analyzes and compares the perspectives for reducing the energy consumption associated to the operation of Heating Ventilation and Air Conditioning system for climatic control of large-size non-residential buildings. Three different control strategies are considered comparing the use of boiler and heat pumps as heating systems and analyzing the use of demand-controlled ventilation, operating on the effective occupancy of the building. The control strategies are applied to two different educational buildings with shapes representative of typical educational structures. The results of the analysis show how the energy consumption can be reduced up to 70%, shifting from the actual values of the energy intensity of over 300 kWh/m2 for year to values of less than 100 kWh/m2 per year. The significance of the energy savings achieved in such different buildings has led to the identification of a possible benchmark for HVAC systems in the next future years which could help reach the environmental targets in this sector
A method for optimal operation of HVAC with heat pumps for reducing the energy demand of large-scale non residential buildings
No full textOne of the key elements for improving the energy performance of large-scale non-residential buildings is recognized as the correct management and control of the Heating Ventilation and Air Conditioning (HVAC) system. In real applications, the main shortcomings are represented by the lack of involving occupants presence and behavior, and by the lack of application of dynamic control able to guarantee optimality of operation with the aim of controlling building energy demand. This present study aims at evaluating the perspective of energy savings achievable with the broadening of the energy perspective to indoor air quality thanks to occupants’ monitoring and at showing some of the potentialities arising from the implementation of an optimal control of the HVAC. This provides insights about the possibility of achieving significant energy savings by using measures of minimal complexity. The proposed measures involve demand-controlled ventilation as representative of occupant-centric control strategies, and an improved control of the heat pump and chiller supply water temperature, and of heat recovery equipment as representative of supervisory control strategies. The analysis which is carried out by means of dynamic simulation has been applied to an academic building situated in Pisa. The achieved energy saving can reach the value of 44%, a significant part (33%) of which is guaranteed by the application of demand-controlled ventilation, consequent to a direct monitoring of the presence inside the building. This shows the major importance of implementing occupant-centric control strategies, which will also return useful in the new paradigm of building occupation after COVID-19 pandemic experience
Energy Indicators for Enabling Energy Transition in Industry
Full text linkEnergy transition is a fundamental process in the move towards sustainable development, but in industry, it is complicated by the remarkable sectoral heterogeneity. Fostering the realization of energy transition in the industrial sector requires the characterization of its energy dimension, in terms of energy mixes and end-uses as the determinants of transition pathways, and energy solutions and tools as the enablers of this transition paradigm. We observe that the suitability of tools for energy analysis depend on trade-offs between comprehensiveness, ease of use, robustness, and generalization ability. In this regard, we discuss the appropriateness of energy indicators and provide an overview of indicator typologies, methodological issues, and applications for energy performance evaluation and improvement. With reference to the dairy processing industry, selected as a representative industrial branch, we outline current and desirable energy benchmarking applications and exemplify the effectiveness of energy indicators in the quantification of the potential of energy solutions. The obtained results are promising and suggest that researchers should further explore the novel applications of energy indicators for energy performance improvement. To foster the establishment of energy indicators in industrial practice and energy policies, we remark that cooperation between industrial stakeholders is essential
Energy efficiency in shared buildings: Quantification of the potential at multiple scales
No full textThe field of non-residential buildings is very heterogeneous. This results in a compartmentalized approach that prevents desired energy efficiency improvements from being achieved at a large scale. This paper proposes a transversal approach to energy efficiency based on the aggregation of building typologies and the integration of the scales of analysis. Upon energy and occupancy analogies we define shared buildings as buildings characterized by a low energy intensity, the predominance of HVAC systems on energy uses, and a large and variable occupancy. This concept gathers in itself a considerable energy efficiency potential, as shared buildings are found to account for 35% of non-residential energy consumption. We overview energy efficiency hotspots and operational criticalities in shared buildings and outline the development of a framework that is fit-for-purpose for the quantification of the energy efficiency potential at multiple scales. Improvement in ventilation energy management in a university stock is used to exemplify the approach: first, we apply dynamic simulation to a single building obtaining 65% HVAC energy savings; then, we generalize the results to the property stock obtaining reductions from 190 to 130 kWh/(m2y) in energy intensity, simultaneously fulfilling the desired energetic and economic targets. (c) 2022 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Clustering of educational building load data for defining healthy and energy-efficient management solutions of integrated HVAC systems
Full text linkThe COVID-19 pandemic is changing the way individuals, worldwide, feel about staying in public indoor spaces. A strict control of indoor air quality and of people's presence in buildings will be the new normal, to ensure a healthy and safe environment. Higher ventilation rates with fresh air are expected to be a requirement, especially in educational buildings, due to their high crowding index and social importance. Yet, in this framework, an increased use of primary energy may be overlooked. This paper offers a methodology to efficiently manage complex HVAC systems in educational buildings, concurrently considering the fundamental goals of occupants' health and energy sustainability. The proposed fourstep procedure includes: dynamic simulation of the building, to generate synthetic energy loads; clustering of the energy data, to identify and predict typical building use profiles; day-ahead planning of energy dispatch, to optimize energy efficiency; dynamic adjustment of air changes, to guarantee a safe indoor air quality. Clustering and forecasting energy needs are expected to become particularly effective in a highly regulated context. The technique has been tested on two university classroom buildings, considering pre-lockdown attendance. This notwithstanding, quality and significance of the obtained thermal energy clusters push towards a benchmark post-pandemic application
Improving energy efficiency through forecast-driven control in hybrid heat pumps
No full textHybrid heat pumps (HHPs) are increasingly used for residential space heating, especially where stand-alone heat pumps (HPs) are inefficient. Typically, HHPs and HVAC systems controls rely on simple rule-based approaches. Smart controllers that employ building-system modeling can improve energy efficiency by determining which heat generation unit to activate and setting the supply water temperature according to actual building heat demand. Data-driven models are particularly suitable for widespread use, as they can self-learn building thermal characteristics and optimize system operation. In this study, we employed an autoregressive model to forecast short-term hourly energy demand and the corresponding water supply temperature to the heat emitters. These predictions helped to estimate generators performance and select the optimal unit to minimize energy costs while meeting heat demand. The predictive control procedure was tested on various case studies, both simulated and field-monitored, representative of the Italian housing stock. Results showed that in non-renovated buildings with radiators, the predictive control strategy can reduce operating costs by up to 20% compared to current commercial HHP controls. This improvement was mainly due to better supply temperature set-point evaluation and increased HP use. Similar benefits were observed in environmental and primary energy metrics. Conversely, in newer, well-insulated houses with low-temperature emitters, current controls are already efficient. Finally, we showed that the proposed control strategy deviates less than 3% from an ideal prediction and control in realistic on-field monitored test cases, representing a valuable trade-off between achievable benefits, data requirements, computational efforts, and implementation feasibility in real industrial HHP devices
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