1,720,967 research outputs found
A comparative life cycle assessment of luminaires for general lighting for the office – compact fluorescent (CFL) vs Light Emitting Diode (LED) – a case study
No full textThe paper presents a life cycle assessment of two lighting technologies based on compact fluorescent (CFL) and Light Emitting Diode (LED) luminaires for the general lighting of the office. The life cycle assessments are carried out considering all the parts of the luminaire: lamp, housing and ballast (or driver for LED). The environmental impact is evaluated considering the whole life cycle of the devices, from manufacturing (including the extraction of raw materials), to use and disposal. An experimental test was conducted to verify the illuminance produced by the two systems. Alternative end-of-life and electricity production scenarios were assessed and compared in order to evaluate possible variations deriving from these changes. The life cycle assessments show that the LED luminaire allows the environmental impacts to be significantly reduced (reduction of 41-50% of greenhouse gas emission and cumulative energy demand), mainly due to high energy efficiency in the use stage. The present paper makes three original contributions: 1) it presents a life cycle assessment (LCA) of a last generation kind of LED and luminaire built for this technology and compares it with a similar CFL luminaire; 2) it presents one of the first LCAs for lighting luminaires made with International Reference Life Cycle Data System (ILCD) 2011 Midpoint; 3) it shows a comparison evaluated with two functional units: 1 lm per 50,000 h and 1 lux per 50,000
Thermal analysis of the application of PCM and low emissivity coating in hollow bricks
No full textThis paper discusses the possibility of increasing the energy performance of thermal brick through integration with two different technologies: the first is based on the insertion of phase change material (PCM) inside the enclosures of the bricks, while the second involves covering the internal surface of the enclosures with low emissivity coating. PCM was employed to increase the thermal mass while the low emissivity coating reduces the overall heat transfer coefficient value. To demonstrate the effectiveness of the solutions, energy evaluation was carried out on the bricks using both theoretical and experimental analyses. Stationary and dynamic analyses were performed. The investigations were made in accordance with Italian, European, and international standards: theoretical analyses were based on the finite elements method, while the experimental tests were carried out with the heat flow meter method. Finally, a comparison is made between the theoretical and experimental data and the error is estimate
Realizzazione di strutture multistrato contenenti Materiali a Cambiamento di Fase (PCM) per la realizzazione di celle frigorifere
No full textI materiali in passaggio di fase (PCM) conferiscono alle strutture leggere inerzia termica per effetto dell'accumulo di calore latente di fusione. Vengono riportati i dati teorico-sperimentali di valutazioni di risparmio energetico effettuate su celle frigorifere per il trasporto su treno di materiali deperibili dotate di materiali in passaggio di fase applicati all'involucro
- Valutazione del comportamento energetico-ambientale e delle condizioni di comfort visivo per apparecchi per l’illuminamento di postazioni di lavoro e definizione dei criteri minimi di ecodesign
No full textVengono riportati i risultati di una ricerca scientifica finalizzata allo studio energetico- ambientale, sia metodologico sia sperimentale, di tecnologie impiantistiche caratterizzate da elevato grado di innovazione tecnologica e da prestazioni energetico-ambientali d’eccellenza, al fine di individuare criteri di progettazione eco-compatibile
A refrigerated container envelope with a PCM (Phase Change Material) layer: Experimental and theoretical investigation in a representative town in Central Italy
No full textIn this paper, a novel technology to improve the thermal performance of reefer container envelopes using a Phase Change Material (PCM) has been investigated. To that end, an external PCM layer was integrated with an insulated sandwich panel, in order to reduce and displace the heat flux phase caused by the external climatic conditions. The proposed technology was evaluated using an experimental and numerical design study. Specifically, during the experimental activities, a prototype panel was first tested inside a climatic test room and subsequently assembled on mini cold rooms and evaluated under real summer environmental conditions in Ancona (Italy). Finally, the numerical analysis was carried out using Finite Element Method (FEM) software in order to simulate a two-dimensional unsteady-state heat transfer with PCM. The calculation results were compared with the experimental values in order to validate the mathematical model, achieving a high reliability (correlation coefficient equal to 0.95)
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
No full textAbstractDuring 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/m2·y, with corresponding 8.52kg 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
Thermal performance analysis of PCM in refrigerated container envelopes in the Italian context - Numerical modeling and validation
No full textDue to external climatic conditions, radiation and temperature, refrigerated containers are subjected to high thermal stresses during storage in yards, warehouses, ships or during transport by rail or road. Moreover the consequent high thermal load has a great influence on both the electric and fuel energy consumption and on combined greenhouse gas emissions into the atmosphere. The aim of this research is the theoretical evaluation, using a previously validated Finite Element Method (FEM), of the related energy benefits deriving from the application of PCMs (Phase Change Materials) to a traditional refrigerated container envelope. Specifically the numerical analysis was performed for several kinds of PCMs, climatic conditions and exposures. The study also provides a numerical tool to be used in the prediction of the thermal performance of refrigerated container envelopes with PCM in the Italian context. An experimental analysis was carried out in order to test the accuracy of the numerical model and to validate it. Results show that PCM application to a 20' ISO container envelope can reduce and shift the daily heat load phases with respect to a traditional envelope fitted only with insulating material
Experimental analysis on a novel air heat exchanger containing PCM (Phase change material) in a cold room
No full textIn the present work the performance of a cold room with a novel air heat exchanger containing PCM (Phase Change Material) was experimentally investigated. Specifically, an air heat exchanger consisting of aluminium containers with finned surface filled with PCM (5 °C melting temperature), was located near the evaporator of a cold room. The aims are to reduce cooling energy consumption and improving the maintenance thermal conditions of stored products. For this purpose, an experimental campaign was carried out and a monitoring system was developed. The cold room thermal behaviour, with and without PCM, was studied under steady state operating conditions. As expected a reduced number of on/off compressor cycles (6 cycles instead 13 cycles) in the PCM added cold room was observed. Test results showed that by storing PCM in the air heat exchanger, up to 16% of energy saving can be achieved
Evaluation of energy conservation opportunities through Energy Performance Contracting: A case study in Italy
Get PDFNon-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
Experimental studies on the effect of using phase change material in a salinity-gradient solar pond under a solar simulator
Get PDFThermal energy storage (TES) is a technology that stocks thermal energy by heating a storage medium so that the stored energy can be used at a later time for heating applications and power generation. This paper is focused on an experimental study of the thermal behavior of a mini Salinity-Gradient Solar Pond (SGSP) exposed to a solar simulator. Experiments were carried out in an environmental chamber. In fact, a comparison between the integration and the absence of Ultra Violet (UV) filter has been done using two experimental prototype solar ponds built at the Environmental Energy Laboratory at the Marche Polytechnic University in Ancona, Italy. Furthermore, representative results illustrating the influence of simulator spectrum on the distribution of temperature on a SGSP and the effects of the thermal performance has been discussed. In the present study, we have also focused on the assessment of Phase Change Material (PCM) properties. For this purpose, the performance of adding salt hydrates PCMs to a small salinity-gradient solar pond has been studied. The obtained result provides evidence that the solar pond with PCM may be used as a hot water source for domestic applications by collecting and storing solar energy at the same point
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