Evaluating in situ thermal transmittance of green buildings masonries—A case study

Abstract The determination of the thermal properties of a building envelope is fundamental for the correct design of energy efficient constructions. Opaque walls can be easily modeled as parallel and homogeneous layers, being characterized by a monodimensional thermal flux which allows to evaluate the thermal transmittance with analytical models. These procedures are well established and they lead to reliable results; however, it is important to verify the actual performance with in situ thermal transmittance measurements. This analysis is more important when the wall performance is high, being closely linked to economic assessments. The paper presents the results of a measurement campaign of in situ thermal transmittance, performed in some buildings in the Umbria Region (Italy), designed implementing bio-architecture solutions. The analyzed walls were previously monitored with thermographic surveys in order to assess the correct application of the sensors. Results of the investigation show that in situ thermal transmittance measurements and theoretical calculated U -value are not in perfect agreement. The mismatch becomes important for monolithic structures such as walls made of thermal blocks without insulating layers

Experimental Performance Analyses of a Heat Recovery System for Mechanical Ventilation in Buildings

Abstract Nowadays the increasing trend to make buildings more and more energetically efficient leads to an improvement of the thermal performance of the elements such us walls, windows and doors, making the envelope a strong barrier between the indoor and outdoor environment, also for air infiltrations. If this circumstance results useful for energy consumption reduction, it constitutes a problem for indoor air quality and comfort. Mechanical ventilation systems are often provided, and, at the aim of abating the thermal (or cooling) loads linked to the inlet of air from the external environment, heat recovery systems became more and more popular; for high values of air mass flow treated, many national regulations make the installation of heat recovery systems compulsory. An experimental test bench was built at the Thermal Engineering Laboratory of the University of Perugia, aimed at evaluating the performance of air heat recovery devices. The first measurements were carried out on a commercial plate-type heat exchanger, made of polystyrene. This plastic material is characterized by a low value of thermal conductivity, but its easiness of workability allows to increase the heat exchange surface, overcoming also issues linked to the weight and the cost of the product. The flow-rates, the pressure drops, and all temperatures of interest for the heat exchanger were acquired. The energy efficiency index of the heat recovery system was assessed with several tests conducted with different boundary conditions of the indoor and outdoor ambient, as well as different air flow rates. Results were compared with data gathered from the manufacturer, highlighting the points of contact and the differences between the experimental outcomes and the company information sheet, providing further details that are commonly not available

Infrared Thermography Assessment of Thermal Bridges in Building Envelope: Experimental Validation in a Test Room Setup

Thermal infrared imaging is a valuable tool to perform non-destructive qualitative tests and to investigate buildings envelope thermal-energy behavior. The assessment of envelope thermal insulation, ventilation, air leakages, and HVAC performance can be implemented through the analysis of each thermogram corresponding to an object surface temperature. Thermography also allows the identification of thermal bridges in buildings' envelope that, together with windows and doors, constitute one of the weakest component increasing thermal losses. A quantitative methodology was proposed in previous researches by the authors in order to evaluate the effect of such weak point on the energy balance of the whole building. In the present work, in-field experimental measurements were carried out with the purpose of evaluating the energy losses through the envelope of a test room experimental field. In-situ thermal transmittance of walls, ceiling and roof were continuously monitored and each element was characterized by its own thermal insulation capability. Infrared thermography and the proposed quantitative methodology were applied to assess the energy losses due to thermal bridges. The main results show that the procedure confirms to be a reliable tool to quantify the incidence of thermal bridges in the envelope thermal losses

Acoustic mitigation of noise in ports: an original methodology for the identification of intervention priorities

Abstract The paper presents an original methodology for the identification of intervention priorities through a tailored priority index IP in areas that are highly-exposed to port noise. The methodology is applied to a case study developed in the framework of the European project ANCHOR, acronym of Advanced Noise Control strategies in HarbOuR, funded as part of the announcement Life 2017. In detail, the paper discusses the results of its application in the assessment of the evolution of port noise impacts in the city of Melilla, Spain. The methodology has been applied considering the port with or without the realization of an expansion project on three different time periods; differences between standard and the summer traffic peak season have been considered. Finally, the paper evaluates the realization of cold ironing in the most impacting port area, the passenger (Ro-Pax) terminal. The results of the analyses demonstrate how the measure is a key action to mitigate noise in port areas. The methodology is not limited to the identification of city areas that needs to be protected; it also aims to identify port areas where anti-noise actions would produce the greatest effect. The index also allows to build a ranking to understand where anti-noise actions are more useful and urgent

Early-Stage Detection of Solid Oxide Cells Anode Degradation by Operando Impedance Analysis

Solid oxide cells represent one of the most efficient and promising electrochemical tech- nologies for hydrogen energy conversion. Understanding and monitoring degradation is essential for their full development and wide diffusion. Techniques based on electrochemical impedance spectroscopy and distribution of relaxation times of physicochemical processes occurring in solid oxide cells have attracted interest for the operando diagnosis of degradation. This research paper aims to validate the methodology developed by the authors in a previous paper, showing how such a diagnostic tool may be practically implemented. The validation methodology is based on applying an a priori known stress agent to a solid oxide cell operated in laboratory conditions and on the discrete measurement and deconvolution of electrochemical impedance spectra. Finally, experi- mental evidence obtained from a fully operando approach was counterchecked through ex-post material characterization

Operando Analysis of Losses in Commercial-Sized Solid Oxide Cells: Methodology Development and Validation

The development of decarbonised systems is being fostered by the increasing demand for technological solutions for the energy transition. Solid Oxide Cells are high-efficiency energy conversion systems that are foreseen for commercial development. They exhibit potential power generation and power-to-gas applications, including a reversible operation mode. Long-lasting high performance is essential for guaranteeing the success of the technology; therefore, it is fundamental to provide diagnosis tools at this early stage of development. In this context, operando analysis techniques help detect and identify incipient degradation phenomena to either counteract damage at its origin or correct operando protocols. Frequent switches from the fuel cell to the electrolyser mode add more challenges with respect to durable performance, and deep knowledge of reverse- operation-induced damage is lacking in the scientific and technical literature. Following on from preliminary experience with button cells, in this paper, the authors aim to transfer the methodology to commercial-sized Solid Oxide Cells. On the basis of the experimental evidence collected on planar square cells under dry and wet reactant feed gases, the main contributions to impedance are identified as being charge transfer (f = 103–104 Hz), oxygen surface exchanged and diffusion in bulk LSCF (f = 102–103 Hz), and gas diffusion in the fuel electrode (two peaks, f = 1–100 Hz). The results are validated using the ECM methodology, implementing an LRel(RctQ)GWFLW circuit

Innovative techniques for the improvement of industrial noise sources identification by beamforming

Abstract An innovative technique based on beamforming is implemented, at the aim of detecting the distances from the observer and the relative positions among the noise sources themselves in multisource noise scenarios. By means of preliminary activities to assess the optical camera focal length and stereoscopic measurements followed by image processing, the geometric information in the source-microphone direction is retrieved, a parameter generally missed in classic beamforming applications. A corollary of the method consists of the possibility of obtaining also the distance among different noise sources which could be present in a multisource environment. A loss of precision is found when the effect of the high acoustic reflectivity ground interferes with the noise source

Energy simulation and LCA for macro-scale analysis of eco-innovations in the housing stock

Purpose: Energy consumption of buildings is one of the major drivers of environmental impacts. Life cycle assessment (LCA) may support the assessment of burdens and benefits associated to eco-innovations aiming at reducing these environmental impacts. Energy efficiency policies however typically focus on the meso- or macro-scale, while interventions are typically taken at the micro-scale. This paper presents an approach that bridges this gap by using the results of energy simulations and LCA studies at the building level to estimate the effect of micro-scale eco-innovations on the macro-scale, i.e. the housing stock in Europe. Methods: LCA and dynamic energy simulations are integrated to accurately assess the life cycle environmental burdens and benefits of eco-innovation measures at the building level. This allows quantitatively assessing the effectiveness of these measures to lower the energy use and environmental impact of buildings. The analysis at this micro-scale focuses on 24 representative residential buildings within the EU. For the upscaling to the EU housing stock, a hybrid approach is used. The results of the micro-scale analysis are upscaled to the EU housing stock scale by adopting the eco-innovation measures to (part of) the EU building stock (bottom–up approach) and extrapolating the relative impact reduction obtained for the reference buildings to the baseline stock model. The reference buildings in the baseline stock model have been developed by European Commission-Joint Research Centre based on a statistical analysis (top–down approach) of the European housing stock. The method is used to evaluate five scenarios covering various aspects: building components (building envelope insulation), technical installations (renewable energy), user behaviour (night setback of the setpoint temperature), and a combined scenario. Results and discussion: Results show that the proposed combination of bottom–up and top–down approaches allow accurately assessing the impact of eco-innovation measures at the macro-scale. The results indicate that a combination of policy measures is necessary to lower the environmental impacts of the building stock to a significative extent. Conclusions: Interventions addressing energy efficiency at building level may lead to the need of a trade-off between resource efficiency and environmental impacts. LCA integrated with dynamic energy simulation may help unveiling the potential improvements and burdens associated to eco-innovations. ispartof: International Journal of Life Cycle Assessment vol:24 issue:6 pages:1-20 status: Published onlin

Guidelines for a common port noise impact assessment: the ANCHOR LIFE project

Abstract The paper reports the main contents of the guidelines developed in the framework of the project ANCHOR, acronym of Advanced Noise Control strategies in HarbOuR, which is a European Project funded as part of the announcement Life 2017. The guidelines represent an updated version of those elaborated in the NoMEPorts project named 'Good Practice Guide on Port Area Noise Mapping and Management'; the aim is to define a common approach in port noise monitoring and assessment, considering the outcomes of previous EU funded projects and the algorithms defined by the European Directive 2015/996, in order to produce Port Noise Impact Assessments to be included in ports Environmental Management Systems (EMS). The procedures described in the guidelines will guide professionals in organizing and managing geographical data, in characterizing noise sources and defining, for each of them, the correct noise emission power level, in evaluating noise propagation and people exposure to noise and, finally, in selecting the most efficient mitigation action by means of a cost benefit analysis. Moreover, the paper reports the results of a comparison between noise mapping outcomes obtained using the new noise mapping algorithms defined by the 2015/996 Directive and the old 2002/49/EC Annex II ones; especially at long distances from the source the differences between the two methodologies are not negligible