7 resultados para Total energy expenditure

em Dalarna University College Electronic Archive


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Energy efficiency and renewable energy use are two main priorities leading to industrial sustainability nowadays according to European Steel Technology Platform (ESTP). Modernization efforts can be done by industries to improve energy consumptions of the production lines. These days, steel making industrial applications are energy and emission intensive. It was estimated that over the past years, energy consumption and corresponding CO2 generation has increased steadily reaching approximately 338.15 parts per million in august 2010 [1]. These kinds of facts and statistics have introduced a lot of room for improvement in energy efficiency for industrial applications through modernization and use of renewable energy sources such as solar Photovoltaic Systems (PV).The purpose of this thesis work is to make a preliminary design and simulation of the solar photovoltaic system which would attempt to cover the energy demand of the initial part of the pickling line hydraulic system at the SSAB steel plant. For this purpose, the energy consumptions of this hydraulic system would be studied and evaluated and a general analysis of the hydraulic and control components performance would be done which would yield a proper set of guidelines contributing towards future energy savings. The results of the energy efficiency analysis showed that the initial part of the pickling line hydraulic system worked with a low efficiency of 3.3%. Results of general analysis showed that hydraulic accumulators of 650 liter size should be used by the initial part pickling line system in combination with a one pump delivery of 100 l/min. Based on this, one PV system can deliver energy to an AC motor-pump set covering 17.6% of total energy and another PV system can supply a DC hydraulic pump substituting 26.7% of the demand. The first system used 290 m2 area of the roof and was sized as 40 kWp, the second used 109 m2 and was sized as 15.2 kWp. It was concluded that the reason for the low efficiency was the oversized design of the system. Incremental modernization efforts could help to improve the hydraulic system energy efficiency and make the design of the solar photovoltaic system realistically possible. Two types of PV systems where analyzed in the thesis work. A method was found calculating the load simulation sequence based on the energy efficiency studies to help in the PV system simulations. Hydraulic accumulators integrated into the pickling line worked as energy storage when being charged by the PV system as well.

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The need for heating and cooling in buildings constitutes a considerable part of the total energy use in a country and reducing this need is of outmost importance in order to reach national and international goals for reducing energy use and emissions. One important way of reaching these goals is to increase the proportion of renewable energy used for heating and cooling of buildings. Perhaps the largest obstacle with this is the often occurring mismatch between the availability of renewable energy and the need for heating or cooling, hindering this energy to be used directly. This is one of the problems that can be solved by using thermal energy storage (TES) in order to save the heat or cold from when it is available to when it is needed. This thesis is focusing on the combination of TES techniques and buildings to achieve increased energy efficiency for heating and cooling. Various techniques used for TES as well as the combination of TES in buildings have been investigated and summarized through an extensive literature review. A survey of the Swedish building stock was also performed in order to define building types common in Sweden. Within the scope of this thesis, the survey resulted in the selection of three building types, two single family houses and one office building, out of which the two residential buildings were used in a simulation case study of passive TES with increased thermal mass (both sensible and latent). The second case study presented in the thesis is an evaluation of an existing seasonal borehole storage of solar heat for a residential community. In this case, real measurement data was used in the evaluation and in comparisons with earlier evaluations. The literature reviews showed that using TES opens up potential for reduced energy demand and reduced peak heating and cooling loads as well as possibilities for an increased share of renewable energy to cover the energy demand. By using passive storage through increased thermal mass of a building it is also possible to reduce variations in the indoor temperature and especially reduce excess temperatures during warm periods, which could result in avoiding active cooling in a building that would otherwise need it. The analysis of the combination of TES and building types confirmed that TES has a significant potential for increased energy efficiency in buildings but also highlighted the fact that there is still much research required before some of the technologies can become commercially available. In the simulation case study it was concluded that only a small reduction in heating demand is possible with increased thermal mass, but that the time with indoor temperatures above 24 °C can be reduced by up to 20%. The case study of the borehole storage system showed that although the storage system worked as planned, heat losses in the rest of the system as well as some problems with the system operation resulted in a lower solar fraction than projected. The work presented within this thesis has shown that TES is already used successfully for many building applications (e.g. domestic hot water stores and water tanks for storing solar heat) but that there still is much potential in further use of TES. There are, however, barriers such as a need for more research for some storage technologies as well as storage materials, especially phase change material storage and thermochemical storage.

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In a Nordic climate, space heating (SH) and domestic hot water (DHW) used in buildings constitute a considerable part of the total energy use in the country. For 2010, energy used for SH and DHW amounted to almost 90 TWh in Sweden which corresponds to 60 % of the energy used in the residential and service sector, or almost 24 % of the total final energy use for the country. Storing heat and cold with the use of thermal energy storage (TES) can be one way of increasing the energy efficiency of a building by opening up possibilities for alternative sources of heat or cold through a reduced mismatch between supply and demand. Thermal energy storage without the use of specific control systems are said to be passive and different applications using passive TES have been shown to increase energy efficiency and/or reduce power peaks of systems supplying the heating and cooling needs of buildings, as well as having an effect on the indoor climate. Results are however not consistent between studies and focus tend to be on the reduction of cooling energy or cooling power peaks. In this paper, passive TES introduced through an increased thermal mass in the building envelope to two single family houses with different insulation standard is investigated with building energy simulations. A Nordic climate is used and the focus of this study is both on the reduction of space heating demand and space heating power, as well as on reduction of excess temperatures in residential single family houses without active cooling systems. Care is taken to keep the building envelope characteristics other than the thermal mass equal for all cases so that any observations made can be derived to the change in thermal mass. Results show that increasing the sensible thermal mass in a single family house can reduce the heating demand only slightly (1-4 %) and reduce excess temperatures (temperatures above 24 degrees C) by up to 20 %. Adding a layer of PCM (phase change materials) to the light building construction can give similar reduction in heating demand and excess temperatures, however the phase change temperature is important for the results.

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With the building sector accounting for around 40% of the total energy consumption in the EU, energy efficiency in buildings is and continues to be an important issue. Great progress has been made in reducing the energy consumption in new buildings, but the large stock of existing buildings with poor energy performance is probably an even more crucial area of focus. This thesis deals with energy efficiency measures that can be suitable for renovation of existing houses, particularly low-temperature heating systems and ventilation systems with heat recovery. The energy performance, environmental impact and costs are evaluated for a range of system combinations, for small and large houses with various heating demands and for different climates in Europe. The results were derived through simulation with energy calculation tools. Low-temperature heating and air heat recovery were both found to be promising with regard to increasing energy efficiency in European houses. These solutions proved particularly effective in Northern Europe as low-temperature heating and air heat recovery have a greater impact in cold climates and on houses with high heating demands. The performance of heat pumps, both with outdoor air and exhaust air, was seen to improve with low-temperature heating. The choice between an exhaust air heat pump and a ventilation system with heat recovery is likely to depend on case specific conditions, but both choices are more cost-effective and have a lower environmental impact than systems without heat recovery. The advantage of the heat pump is that it can be used all year round, given that it produces DHW. Economic and environmental aspects of energy efficiency measures do not always harmonize. On the one hand, lower costs can sometimes mean larger environmental impact; on the other hand there can be divergence between different environmental aspects. This makes it difficult to define financial subsidies to promote energy efficiency measures.

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the work towards increased energy efficiency. In order to plan and perform effective energy renovation of the buildings, it is necessary to have adequate information on the current status of the buildings in terms of architectural features and energy needs. Unfortunately, the official statistics do not include all of the needed information for the whole building stock.   This paper aims to fill the gaps in the statistics by gathering data from studies, projects and national energy agencies, and by calibrating TRNSYS models against the existing data to complete missing energy demand data, for countries with similar climate, through simulation. The survey was limited to residential and office buildings in the EU member states (before July 2013). This work was carried out as part of the EU FP7 project iNSPiRe.   The building stock survey revealed over 70% of the residential and office floor area is concentrated in the six most populated countries. The total energy consumption in the residential sector is 14 times that of the office sector. In the residential sector, single family houses represent 60% of the heated floor area, albeit with different share in the different countries, indicating that retrofit solutions cannot be focused only on multi-family houses.   The simulation results indicate that residential buildings in central and southern European countries are not always heated to 20 °C, but are kept at a lower temperature during at least part of the day. Improving the energy performance of these houses through renovation could allow the occupants to increase the room temperature and improve their thermal comfort, even though the potential for energy savings would then be reduced.

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Syftet med denna studie var att belysa hur viktig nutritionen är för patienter med diagnosen KOL (Kronisk Obstruktiv Lungsjukdom). Författarna ville även visa på enkla metoder för sjuksköterskan att bedöma nutritionsstatus för att förebygga malnutrition hos dessa patienter. Denna studie är en systematisk litteraturstudie där författarna använt sig av databaserna ELIN@Dalarna, CINAHL, Blackwell Synergy och SWEMED+ för att söka vetenskapliga artiklar. Sökorden som användes i olika kombinationer var: COPD, nutrition, malnutrition, undernutritioned, nutritionalstatus, nutritional supplement, BMI, energy expenditure, caring och nursing. Resultatet visade att nutritionen är av central betydelse i behandlingen av KOL patienter där sjuksköterskan har en viktig roll i samarbetet med andra yrkeskategorier såsom läkare, dietist, sjukgymnast, arbetsterapeut, kurator och psykolog. Bedömningen av patientens nutritionsstatus är en väsentlig del av sjuksköterskans omvårdnad av KOL patienter då det påverkar prognosen. Patienternas försämrade nutritionsstatus ökar risken för exacerbationer och därmed också risken för dödlighet.Sjuksköterskan kan använda sig av enkla mätmetoder för att upptäcka malnutrition, till exempel BMI (Body Mass Index) och MNA (Mini Nutritional Assessment). Ett steg i att förebygga malnutrition är regelbundna viktkontroller och att varje patient har en individuell åtgärdsplan då patientens behov alltid ska komma i första hand. Det är också viktigt att se till psykosociala aspekter runt måltiderna för dessa patienter. En noggrann planering krävs runt deras måltider som patienten kan behöva hjälp med då sjukdomen utgör ett hinder.För en ökad livskvalitet är det angeläget med information om nutritionens betydelse både till patienten och hans anhöriga.

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Syfte: Att mäta turisternas konsumtion i samband med ett större idrottsevenemang samt att beräkna skatte- och sysselsättningseffekter till följd av denna under Skid-VM i Falun år 2015. Metod: Turisternas konsumtion har i denna studie mätts genom att ett urval av besökarna på Skidspelen 2013 fört dagbok över sin konsumtion. Vi har även använt sekundärdata i form av en konsumtionsundersökning som är genomförd under Svenska Skidspelen 2012 samt uppgifter från en rapport författad av HUI Research AB. Slutsats: Tre olika scenarion har använts för att beräkna skatte och sysselsättningseffekter. Ett lågt scenario där vi räknar med 140 000 sålda endagsbiljetter vilket är samma antal som Skid- VM i Falun 1993. Ett medelhögt där vi räknar med 200 000 sålda endagsbiljetter vilket är vad arrangören förväntar sig samt slutligen ett högt scenario med 270 000 sålda endagsbiljetter vilket är vad som såldes under Skid-VM i Oslo 2011. Beroende på valt scenario kommer turisternas totala konsumtion i regionen att uppgå till mellan 147 och 197 miljoner kronor. Denna omsättningsökning uppskattas leda till att mellan 85 och 111 arbetstillfällen skapas i regionen på kort sikt. Summan av samtliga skatter och avgifter uppgår till mellan 27 och 36 miljoner kronor.