Search results for " Thermal"
showing 10 items of 492 documents
Life cycle assessment of a solar thermal collector
2005
Abstract The renewable energy sources are often presented as ‘clean’ sources, not considering the environmental impacts related to their manufacture. The production of the renewable plants, like every production process, entails a consumption of energy and raw materials as well as the release of pollutants. Furthermore, the impacts related to some life cycle phases (as maintenance or installation) are sometimes neglected or not adequately investigated. The energy and the environmental performances of one of the most common renewable technologies have been studied: the solar thermal collector for sanitary warm water demand. A life cycle assessment (LCA) has been performed following the inter…
Life Cycle Assessment of Solar Technologies
2015
This chapter analyses the most common solar technologies and assesses their energy and environmental performance, based on a life cycle perspective. After a preliminary description of the main technologies, the chapter presents a review of studies on solar plants, as published in scientific journals in the past decade. Successively, the chapter assesses solar plants in comparison to other renewable and non-renewable based technologies, including a discussion of uncertainties and criticalities in the assessment
Annual heating energy requirements of office buildings in a European climate
2016
Abstract The concept of implementing energy savings to reduce greenhouse gas emissions has become a key element of energy policies of any industrialized country. In the civil sector and specifically, energy savings for office buildings, there are still opportunities for further enhancements related to correctly determining the air conditioning thermal requirements. However, there is a lack of simple correlations that allow a preliminary assessment for a single building or correlations that can be quickly applied at the district level. This paper proposes several simple correlations that determine the heating loads of a typical office building by only knowing the Degree-Days of a specific Eu…
Is the transfer function method reliable in a European building context? A theoretical analysis and a case study in the South of Italy
2005
Abstract The available tools for dynamic simulation of the buildings thermal behaviour are manifold, and the most modern ones, known as TRNSYS, are founded upon the use of the Z-transform (ZT) set also called transfer function method (TFM). The transfer function method (TFM), recommended by American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), is one of the most modern tools available to solve heat transfer problems in building envelopes and environments. TFM utilises Z-transforms to solve the equation system that describes the heat transfer in a multi-layered wall. Due to an analogy with an electric circuit, it is possible to write the equation system in a mat…
Comparing different control strategies for indoor thermal comfort aimed at the evaluation of the energy cost of quality of building
2010
Abstract The rapid improvement in the standard of living requires more detailed and sophisticated methods of evaluating comfort conditions. But, maintaining thermal comfort conditions in confined environments may require complex regulation procedures and the proper management of heating, ventilating and air conditioning (HVAC) systems. In turn, the requirements for indoor thermal comfort do not necessarily coincide with those of energy saving purposes, which in the last years are becoming a crucial issue owing to the enactment of the European Energy Performance of Buildings Directive (EPBD). The aim of this work is to compare different indoor control thermal comfort strategies in view of th…
Membrane distillation: Solar and waste heat driven demonstration plants for desalination
2013
Abstract The development of small to medium size, autonomous and robust desalination units is needed to establish an independent water supply in remote areas. This is the motivation for research on alternative desalination processes. Membrane distillation (MD) seems to meet the specific requirements very well. This work is focused on experimental studies on full scale demonstration systems, utilizing a parallel multi MD-module setup. Three different plant concepts are introduced, one of them is waste heat driven and two of them are powered by solar thermal collectors. Design parameters and system design are presented. After the analysis of plant operation a comparison among the plants as we…
Optimization of a thermoelectric system for power generation realized by ‘‘hidden’’ components
2014
Abstract Today the utilization of renewable energy sources is very important to support the traditional ones, and also in order to reach the objectives fixed by the Kyoto Protocol. In this context, also well-known technologies related to the electric energy production, formerly not suitable – due to the poor technological level of the components or due to the high costs linked to the system efficiency – may now find a suitable collocation. Among these technologies, the thermoelectric effect may be very advantageous in some particular applications of small power. A power generation system utilizing this technology has been studied by the authors. This system utilizes the thermal difference b…
Performance evaluation of CHCP hybrid seawater desalination plants
2007
There are many ways to improve efficiency and reduce fresh water cost in desalination plants, like the integration of two or more desalination systems into a hybrid mechanical/thermal lay-out. Most common results that could be achieved by hybrid systems are savings in pretreatments, overall cost reduction and significant primary energy savings, especially when cogeneration unit are concerned. In this paper a small size (2000 m 3 /day) thermal desalination system (MEE) is coupled with a single-stage seawater reverse osmosis (SWRO) system; the system is fed by a natural gas (NG) reciprocate engine, where heat is recovered both from exhaust gases and from the cooling jacket water circuit. Tech…
Conceptual study of the coupling of a biorefinery process for hydrothermal liquefaction of microalgae with a concentrating solar power plant
2017
A conceptual analysis of the coupling of a concentrating solar power plant with a chemical process for hydrothermal liquefaction (HTL) of microalgae to biocrude was performed. The two plants were considered coupled by molten salt recirculation that granted energetic supply to the chemical process. Preliminary estimations have been done considering a solar field constituted by 3 linear parabolic solar collectors rows, each 200 m long, using a ternary molten salts mixture as heat transfer fluid, and a chemical plant sized to process 10 kT/y of microalgae. Under adopted conditions, we have estimated a minimum selling prize of the biocrude that is similar to that achieved in non-solar HTL proce…
A systematic literature review on less common natural fibres and their biocomposites
2018
Abstract Interest in utilization of renewable resources is increasing because of public's environmental awareness and economic considerations. Lignocellulosic fibres have already attracted growing attention as reinforcement of polymeric matrices instead of synthetic ones (mainly glass) from the academic and industrial fields. In addition to kenaf, hemp, sisal, flax and jute, which are the subject of extensive investigations for composite applications since the 1970s, in the last years several researchers suggested the use of less common natural fibres, due to their low cost and availability. This paper reviews the extraction methods, chemical, morphological, thermal and mechanical propertie…