153 research outputs found
Thermal Performance of Hollow Clay Brick with Low Emissivity Treatment in Surface Enclosures
External walls made with hollow clay brick or block are widely used for their thermal, acoustic and structural properties. However, the performance of the bricks frequently does not conform with the minimum legal requirements or the values required for high efficiency buildings, and for this reason, they need to be integrated with layers of thermal insulation. In this paper, the thermal behavior of hollow clay block with low emissivity treatment on the internal cavity surfaces has been investigated. The purpose of this application is to obtain a reduction in the thermal conductivity of the block by lowering the radiative heat exchange in the enclosures. The aims of this paper are to indicate a methodology for evaluating the thermal performance of the brick and to provide information about the benefits that should be obtained. Theoretical evaluations are carried out on several bricks (12 geometries simulated with two different thermal conductivities of the clay), using a finite elements model. The heat exchange procedure is implemented in accordance with the standard, so as to obtain standardized values of the thermal characteristics of the block. Several values of emissivity are hypothesized, related to different kinds of coating. Finally, the values of the thermal transmittance of walls built with the evaluated blocks have been calculated and compared. The results show how coating the internal surface of the cavity provides a reduction in the thermal conductivity of the block, of between 26% and 45%, for a surface emissivity of 0.1
Chapter Feasibility study of a cold ironing system and district heating in port area
Cold ironing is a technology to reduce polluting emissions covering the energy demand of berthed ships in port to shut down their auxiliary engines. A feasibility study for the port of Ancona is proposed. A cogeneration plant provides electricity to ships, and the recovered heat waste is used in a district heating network. Results show that a 1.5MW and 2MW cogenerator covers 83% and 92% of the electrical need of ships respectively, and 61% and 74% of the thermal need of the involved buildings over the analysed period. The scenarios have been economically evaluated and prove to be feasible
The Contribution of the ITACA Protocol in the Control of the Environmental Quality in Residential Buildings and the Subsequent Contribution to the Adaptation to Climatic Change
Abstract During the last years the aim to reduce environmental impacts in the building sector has led to the development of assessment methods called protocols, to certify the sustainable quality of the building, such as the ITACA Protocol. In the present work the national version 2011 of the ITACA Protocol has been applied to several residential buildings study cases, and the resulting performances have been compared with a reference building with the same geometric shape and performances within the limit of the law. These results have been compared with the average energy performance of an Italian residential estate, to evaluate the contribution to climate change adaption. Furthermore, the comparison has also been carried out from the costs point of view, to verify the necessity of long-term subsidizing policies. The criteria used to analyze the effective impact reduction are: primary energy for heating and hot water and related CO2 emissions. The average value of savings in energy consumption obtained in the evaluated building (designed and certified with the ITACA Protocol, compared to reaching the law limit value) is 51.25 kWh/m 2 ·y, with corresponding 8.52 kg CO2/m2·y emissions saved. Intervening on 22% of the current Italian housing estates with the performances of the study cases, results in a reduction of the energy load of 20.10%. Whilst from the technical point of view the application could be easily adopted, the high costs of these interventions still have a long payback period, and it could be necessary to provide a durable public incentive
Evaluation of energy conservation opportunities through Energy Performance Contracting: A case study in Italy
Non-residential buildings like healthcare ones contribute to energy consumption and cause a negative environmental impact. This is mainly due to the age of the buildings, their poor level of energy efficiency and the implementation of only a basic maintenance plan. Owing to the very limited budget available for public administrators, Energy Performance Contracting (EPC), that entails the involvement of an Energy Service Company (ESCo), can provide the entire or part of the capital needed for investments aimed at progressively increasing energy efficiency over their service life. In this paper, three acute hospitals and two community clinics built in Italy are analysed, in order to assess the economic feasibility of several energy renovation actions that can be included within EPC contracts. To this purpose, the outcomes of energy audits carried out in 2014 about these buildings are reported, which involved analyses of consumption measured over the previous three years and assessment of use profiles for the development of models to break down the overall consumption and to estimate potential savings. Diverse improvement strategies were assessed, consisting in either isolated or combined renovation actions and tested on the five buildings, whose comparison was carried out in terms of energy saving, pollution reduction and economic feasibility. As a result, the best combined renovation actions per each hospital were recommended, that included - but were not limited to - the improvement of the control and regulation of existing sub-systems without replacement, partial replacement of other sub-systems and integration of renewables. Finally, each scenario was evaluated through the payback period and other economic performance indexes in order-to assess the feasibility of the EPC framework when applied to this case study
Managing Energy Retrofit of Acute Hospitals and Community Clinics through EPC Contracting: The MARTE Project
Abstract Acute hospitals and community clinics contribute to energy consumption and have a negative environmental impact. This is mainly due to the age of the buildings, a poor level of energy efficiency and a basic maintenance plan. Owing to the very limited money available for public administrators, Energy Performance Contracting (EPC), involving an Energy Service Company (ESCo), can provide the capital needed for investments aimed at increasing energy efficiency. In this paper three acute hospitals and two community clinics in Italy are analyzed prior to EPC development in order to assess the economic feasibility of retrofit strategies. The outcome of energy audits carried out in 2014, the analyses of consumption measured over the last 3 years, and the assessment of use profiles were all considered for the development of models to break down the overall consumption and to assess potential savings. Recommended improvement strategies include better insulation in envelopes, enhancement of mechanical and lighting equipment, use of renewable energy, better regulation of systems. Finally, payback periods for the most likely scenarios were evaluated
Analisi teorico sperimentale del comportamento energetico di pannelli fotovoltaici raffreddati da materiali a cambiamento di fase
The influence of operator position, height and body orientation on eye lens dose in interventional radiology and cardiology: Monte Carlo simulations versus realistic clinical measurements
Objective:This paper aims to provide some practical recommendations to reduce eye lens dose for work-ers exposed to X-rays in interventional cardiology and radiology and also to propose an eye lens correc-tion factor when lead glasses are used.Methods:Monte Carlo simulations are used to study the variation of eye lens exposure with operatorposition, height and body orientation with respect to the patient and the X-ray tube. The paper also looksinto the efficiency of wraparound lead glasses using simulations. Computation results are compared withexperimental measurements performed in Spanish hospitals using eye lens dosemeters as well as withdata from available literature.Results:Simulations showed that left eye exposure is generally higher than the right eye, when the oper-ator stands on the right side of the patient. Operator height can induce a strong dose decrease by up to afactor of 2 for the left eye for 10-cm-taller operators. Body rotation of the operator away from the tube by45°–60°reduces eye exposure by a factor of 2. The calculation-based correction factor of 0.3 for wrap-around type lead glasses was found to agree reasonably well with experimental data.Conclusions:Simple precautions, such as the positioning of the image screen away from the X-ray source,lead to a significant reduction of the eye lens dose. Measurements and simulations performed in thiswork also show that a general eye lens correction factor of 0.5 can be used when lead glasses are wornregardless of operator position, height and body orientation.Postprint (author's final draft
Recombinant activated protein C treatment improves tissue perfusion and oxygenation in septic patients measured by near-infrared spectroscopy
INTRODUCTION: The purpose was to test the hypothesis that muscle perfusion, oxygenation, and microvascular reactivity would improve in patients with severe sepsis or septic shock during treatment with recombinant activated protein C (rh-aPC) (n = 11) and to explore whether these parameters are related to macrohemodynamic indices, metabolic status or Sequential Organ Failure Assessment (SOFA) score. Patients with contraindications to rh-aPC were used as a control group (n = 5). MATERIALS AND METHODS: Patients were sedated, intubated, mechanically ventilated, and hemodynamically monitored with the PiCCO system. Tissue oxygen saturation (StO2) was measured using near-infrared spectroscopy (NIRS) during the vascular occlusion test (VOT). Baseline StO2 (StO2 baseline), rate of decrease in StO2 during VOT (StO2 downslope), and rate of increase in StO2 during the reperfusion phase were (StO2 upslope) determined. Data were collected before (T0), during (24 hours (T1a), 48 hours (T1b), 72 hours (T1c) and 96 hours (T1d)) and 6 hours after stopping rh-aPC treatment (T2) and at the same times in the controls. At every assessment, hemodynamic and metabolic parameters were registered and the SOFA score calculated. RESULTS: The mean +/- standard deviation Acute Physiology and Chronic Health Evaluation II score was 26.3 +/- 6.6 and 28.6 +/- 5.3 in rh-aPC and control groups, respectively. There were no significant differences in macrohemodynamic parameters between the groups at all the time points. In the rh-aPC group, base excess was corrected (P < 0.01) from T1a until T2, and blood lactate was significantly decreased at T1d and T2 (2.8 +/- 1.3 vs. 1.9 +/- 0.7 mmol/l; P < 0.05). In the control group, base excess was significantly corrected at T1a, T1b, T1c, and T2 (P < 0.05). The SOFA score was significantly lower in the rh-aPC group compared with the controls at T2 (7.9 +/- 2.2 vs. 12.2 +/- 3.2; P < 0.05). There were no differences between groups in StO2 baseline. StO2 downslope in the rh-aPC group decreased significantly at all the time points, and at T1b and T2 (-16.5 +/- 11.8 vs. -8.1 +/- 2.4%/minute) was significantly steeper than in the control group. StO2 upslope increased and was higher than in the control group at T1c, T1d and T2 (101.1 +/- 62.1 vs. 54.5 +/- 23.8%/minute) (P < 0.05). CONCLUSIONS: Treatment with rh-aPC may improve muscle oxygenation (StO2 baseline) and reperfusion (StO2 upslope) and, furthermore, rh-aPC treatment may increase tissue metabolism (StO2 downslope). NIRS is a simple, real-time, non-invasive technique that could be used to monitor the effects of rh-aPC therapy at microcirculatory level in septic patient
State-of-the-art Review : Vol. 1. State-of-the-art Report:NNEX 44 : Integrating Environmentally Responsive Elements in Buildings
EURADOS Working Group 12 studies in interventional radiology for medical staff dosimetry
EURADOS (European Radiation Dosimetry Group) Working Group 12 (dosimetry in medical imaging) established a subtask devoted to the dosimetry of the medical staff employed in interventional radiology practices. As it is widely known, such practices are characterized by high doses, with respect the other medical procedures, both for the patient and the radiologist. For interventional cardiology there are several publications concerning medical staff dosimetry, on the contrary, for interventional radiology, data are more limited. For that reason WG12 decided to study the irradiation scenario, employing simplified anthropomorphic models (MIRD type) with Monte Carlo simulations, reconstructing some specific interventional radiology practices (PTC and TIPS). In these procedures, where the X-ray C-arm is mainly fixed in PA projection and the beam directed to the patient abdomen, the radiologist is next to the patient right side, in correspondence to the liver region. The usage of the ceiling shielding is not very frequent, due to the difficulties in positioning it between the radiation source (the X-ray and the patient as the scattering source) and the operator. The aim of the simulations program is: to evaluate the dose received by the radiologist, in a region simulating the presence of the dosemeter fixed on the lead apron at the breast level; to estimate the corresponding effective dose; to make a sensitivity analysis on different parameters affecting the calculated results (as the reciprocal position between the two operators, the beam quality and the X-ray field dimension). Indeed a particular attention is devoted to the eye lens dosimetry, that has become a “critical issue” for personnel dosimetry, after ICRP has reconsidered the radiation sensitivity of the lens of the eye. In the present work the general scheme, the assumptions and the followed methodology are presented with some very preliminary results of the simulations and the measurements
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