Search results for "HV"
showing 10 items of 353 documents
Poor nutritional quality of primary producers and zooplankton driven by eutrophication is mitigated at upper trophic levels
2022
Eutrophication and rising water temperature in freshwaters may increase the total production of a lake while simultaneously reducing the nutritional quality of food web components. We evaluated how cyanobacteria blooms, driven by agricultural eutrophication (in eutrophic Lake Köyliöjärvi) or global warming (in mesotrophic Lake Pyhäjärvi), influence the biomass and structure of phytoplankton, zooplankton, and fish communities. In terms of the nutritional value of food web components, we evaluated changes in the ω-3 and ω-6 polyunsaturated fatty acids (PUFA) of phytoplankton and consumers at different trophic levels. Meanwhile, the lakes did not differ in their biomasses of phytoplankton, zoo…
Do we value mobility?
2015
Is there a trade-off between people's preference for income equality and income mobility? Testing for the existence of such a trade-off is difficult because mobility is a multifaceted concept. We analyse results from a questionnaire experiment based on simple precise concepts of income inequality and income mobility. We fnd no direct trade-off in preference between mobility and equality, but an indirect trade-off, applying when more income mobility can only be obtained at the expense of some income inequality. Mobility preference - but not equality preference - appears to be driven by personal experience of mobility.
Work-related and personal predictors of COVID-19 transmission: evidence from the UK and USA
2021
ObjectiveTo develop evidence of work-related and personal predictors of COVID-19 transmission.Setting and respondentsData are drawn from a population survey of individuals in the USA and UK conducted in June 2020.Background methodsRegression models are estimated for 1467 individuals in which reported evidence of infection depends on work-related factors as well as a variety of personal controls.ResultsThe following themes emerge from the analysis. First, a range of work-related factors are significant sources of variation in COVID-19 infection as indicated by self-reports of medical diagnosis or symptoms. This includes evidence about workplace types, consultation about safety and union memb…
Energy Storage by using HVDC Power Cables
2018
The development of HVDC (high voltage direct current) systems closely follow the growth of global energy requirements. In particular, HVDC cables are conveniently used for the interconnection of geographical areas which need a low environmental impact and/or when submarines interconnections have to be built up. The paper investigates the stored energy value in an HVDC cable during its normal duty and if it is possible to take advantage of this energy when the cable is disconnected for some reason. In particular, the idea is to store the cable energy, which would be dissipated uselessly, by using a dedicated system and then reuse it when favorable conditions hold, e.g a convenient economic s…
The control of indoor thermal comfort conditions: introducing a fuzzy adaptive controller
2004
The control and the monitoring of indoor thermal conditions represents a pre-eminent task with the aim of ensuring suitable working and living spaces to people. Especially in industrialised countries, in fact, several rules and standards have been recently released in order of providing technicians with suitable design tools and effective indexes and parameters for the checking of the indoor microclimate. Among them, predicted mean vote (PMV) index is often adopted for assessing the thermal comfort conditions of thermal moderate environments. Unfortunately, the PMV index is characterised by non-linear features, that could determine some difficulties when monitoring and controlling HVAC equi…
An Overview on Solar Shading Systems for Buildings
2014
Abstract In recent years, different types of solar shading devices have been proposed, depending on building orientation, location, window characteristics, etc. They can contribute to improve or worsen building thermal and lighting performances both from an energy and comfort point of view. The present paper reports a critical analysis of some studies that investigate shading devices’ effects on building thermal and/or lighting performances. This article points out the difficulty in comparing the different results given the lack of uniformity between the studies, since they analysed buildings with different characteristics, locations and using various indices. Therefore a protocol to carry …
Benefits of Refurbishment
2013
Energy and environmental performances of buildings strictly depend on many factors related to the choice of construction materials, HVAC plants and equipment, design, installation and use. By definition, a building interacts closely with its environment. The interactions between building and climate, plants and users have to be taken into account. This aspect is evident in new buildings design process, but it is even more important in the design phase of an existing building renovation, during which actions of energy saving are developed. This chapter summarises the results of the energy and environmental assessment of a set of retrofit actions implemented in the framework of the EU Project…
Regional policies for sustainability in the Mediterranean countries: the role of a proper HVAC system maintenance in museums
2013
Italy, like several Mediterranean countries, holds a very large number of cultural artifacts that are often exhibited and saved inside museums. Museums are usually part of historical buildings that, not rarely, originally had a different intended use and that have been currently transformed in place for conservation and for exhibition of works of art. The use of historical buildings as museums leads to limitations in the management and distribution of exhibition space, in design and managing HVAC systems and in the achievement of targets relating to the continuous monitoring of the microclimate for people comfort and for preservation of works of art. Moreover, the costs of the operation and…
On the effects of HV/MV stations on global grounding systems
2016
The METERGLOB project has faced the issue of the identification of Global Grounding Systems. One of the main point of the problem is to define if an interconnection of single grounding systems gives place to a Global Grounding System in any condition and for every kind of ground fault. This paper focuses the attention on what happens in the case of single line to ground fault inside a HV/MV station whose ground electrode is connected to the cable' shields of the MV lines outgoing the station and supplying the secondary substations of a given area.
Short-term prediction of household electricity consumption: assessing weather sensitivity in a Mediterranean area
2008
Abstract Urban microclimatic variations, along with a rapid reduction of unit cost of air-conditioning (AC) equipments, can be addressed as some of the main causes of the raising residential energy demand in the more developed countries. This paper presents a forecasting model based on an Elman artificial neural network (ANN) for the short-time prediction of the household electricity consumption related to a suburban area. Due to the lack of information about the real penetration of electric appliances in the investigated area and their utilization profiles it was not possible to implement a statistical model to define the weather and climate sensitivities of appliance energy consumption. F…