17 resultados para Renewable energy. Solar dryer. Forced convection. Licuri


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Within the framework of the REBUS project the German building industry has been investigated regarding their energy concepts. The intention was to evaluatethe establishment of renewable energy sources on the German market for new built houses and prefab houses in particular. For this purpose the products of 85manufacturers of prefab houses have been analyzed. Of special interest was the applicationof heating and hot water systems driven by solar energy and biomass. The results show that both techniques are well accepted and established. Almost 90% of themanufacturers offer solar systems on request and almost 70% heating systems based on Pellets. 24% offered solar and 7% as standard options in their range. From theachieved figures the potential of the Swedish market can be worked out. Strategies to introduce renewable energy to a greater extent to Swedish house manufacturers and builders might also be found.

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During November and December 1992 I visited several groups involved with renewable energy, most of them dealing with education. These groups and their work are described briefly in this report. The groups in Melbourne, Australia have come a long way with education in this field and we have a lot to learn from them. Government funding is needed for large scale work, but useful work can still be done at the community level with much smaller budgets.

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This report describes the outcome of the first visit to Tanzania, within the project "Mini-grids supplied by renewable energy - improving technical and social feasibility". The trip included visits to three different organizations; Ihushi Development Center (IDC) near Mwanza, TIDESO near Bukoba, and Mavuno Project in Karagwe. At IDC, a brief evaluation of the current power system was done and measuring equipment for long term measurements were installed. At all three locations investigations regarding the current and future electricity demand were conducted and connections to people relevant to the study were established. The report is including as well some technical specifications as some observations regarding organization and management of the technical systems. The trip was including only short visits and therefore only brief introductions to the different organizations, based on observations done by the author. The report is hence describing the author’s understanding of the technical system and social structures after only short visits to each of the organizations, and may differ from observations done at another point in time, over a different time period, or by some other person.This report describes the outcome of the first visit to Tanzania, within the project "Mini-grids supplied by renewable energy - improving technical and social feasibility". The trip included visits to three different organizations; Ihushi Development Center (IDC) near Mwanza, TIDESO near Bukoba, and Mavuno Project in Karagwe. At IDC, a brief evaluation of the current power system was done and measuring equipment for long term measurements were installed. At all three locations investigations regarding the current and future electricity demand were conducted and connections to people relevant to the study were established. The report is including as well some technical specifications as some observations regarding organization and management of the technical systems. The trip was including only short visits and therefore only brief introductions to the different organizations, based on observations done by the author. The report is hence describing the author’s understanding of the technical system and social structures after only short visits to each of the organizations, and may differ from observations done at another point in time, over a different time period, or by some other person.

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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 new Popular Science Park TEKNOLAND in Falun contains a number of interactive solar energy exhibits, including The Solar Heated Chess Board, The Solar Electric Playhouse, The Sudanese Solar Oven, and Solar Collector Optics. The TeknoTrix tutored children activities include solar thermal activities. Some related interactive exhibits are planned to be included during the summer and during coming years.

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This thesis evaluates different sites for a weather measurement system and a suitable PV- simulation for University of Surabaya (UBAYA) in Indonesia/Java. The weather station is able to monitor all common weather phenomena including solar insolation. It is planned to use the data for scientific and educational purposes in the renewable energy studies. During evaluation and installation it falls into place that official specifications from global meteorological organizations could not be meet for some sensors caused by the conditions of UBAYA campus. After arranging the hardware the weather at the site was monitored for period of time. A comparison with different official sources from ground based and satellite bases measurements showed differences in wind and solar radiation. In some cases the monthly average solar insolation was deviating 42 % for satellite-based measurements. For the ground based it was less than 10 %. The average wind speed has a difference of 33 % compared to a source, which evaluated the wind power in Surabaya. The wind direction shows instabilities towards east compared with data from local weather station at the airport. PSET has the chance to get some investments to investigate photovoltaic on there own roof. With several simulations a suitable roof direction and the yearly and monthly outputs are shown. With a 7.7 kWpeak PV installation with the latest crystalline technology on the market 8.82 MWh/year could be achieved with weather data from 2012. Thin film technology could increase the value up to 9.13 MWh/year. However, the roofs have enough area to install PV. Finally the low price of electricity in Indonesia makes it not worth to feed in the energy into the public grid.

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Genetic algorithm has been widely used in different areas of optimization problems. Ithas been combined with renewable energy domain, photovoltaic system, in this thesis.To participate and win the solar boat race, a control program is needed and C++ hasbeen chosen for programming. To implement the program, the mathematic model hasbeen built. Besides, the approaches to calculate the boundaries related to conditionhave been explained. Afterward, the processing of the prediction and real time controlfunction are offered. The program has been simulated and the results proved thatgenetic algorithm is helpful to get the good results but it does not improve the resultstoo much since the particularity of the solar driven boat project such as the limitationof energy production

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The present paper examines building integrated solar collectors with absorbers of polymeric materials. Efficiency measurements of façade-integrated collectors with non-selective black and spectrally selective coloured absorbers are carried out. The performance of the polymeric absorber was compared with solar glass and polycarbonate twin-wall sheets as collector cover. Simulations demonstrate a high solar fraction for a solar combisystem with façade collectors for a well-insulated house in a Nordic climate. Two examples of house concepts with façade collectors are presented which address a new type of customer than the solar enthusiasts with special interest in renewable energy

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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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The demand for cooling and air-conditioning of building is increasingly ever growing. This increase is mostly due to population and economic growth in developing countries, and also desire for a higher quality of thermal comfort. Increase in the use of conventional cooling systems results in larger carbon footprint and more greenhouse gases considering their higher electricity consumption, and it occasionally creates peaks in electricity demand from power supply grid. Solar energy as a renewable energy source is an alternative to drive the cooling machines since the cooling load is generally high when solar radiation is high. This thesis examines the performance of PV/T solar collector manufactured by Solarus company in a solar cooling system for an office building in Dubai, New Delhi, Los Angeles and Cape Town. The study is carried out by analyzing climate data and the requirements for thermal comfort in office buildings. Cooling systems strongly depend on weather conditions and local climate. Cooling load of buildings depend on many parameters such as ambient temperature, indoor comfort temperature, solar gain to the building and internal gains including; number of occupant and electrical devices. The simulations were carried out by selecting a suitable thermally driven chiller and modeling it with PV/T solar collector in Polysun software. Fractional primary energy saving and solar fraction were introduced as key figures of the project to evaluate the performance of cooling system. Several parametric studies and simulations were determined according to PV/T aperture area and hot water storage tank volume. The fractional primary energy saving analysis revealed that thermally driven chillers, particularly adsorption chillers are not suitable to be utilizing in small size of solar cooling systems in hot and tropic climates such as Dubai and New Delhi. Adsorption chillers require more thermal energy to meet the cooling load in hot and dry climates. The adsorption chillers operate in their full capacity and in higher coefficient of performance when they run in a moderate climate since they can properly reject the exhaust heat. The simulation results also indicated that PV/T solar collector have higher efficiency in warmer climates, however it requires a larger size of PV/T collectors to supply the thermally driven chillers for providing cooling in hot climates. Therefore using an electrical chiller as backup gives much better results in terms of primary energy savings, since PV/T electrical production also can be used for backup electrical chiller in a net metering mechanism.

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PV-Wind-Hybrid systems for stand-alone applications have the potential to be more cost efficient compared to PV-alone systems. The two energy sources can, to some extent, compensate each others minima. The combination of solar and wind should be especially favorable for locations at high latitudes such as Sweden with a very uneven distribution of solar radiation during the year. In this article PV-Wind-Hybrid systems have been studied for 11 locations in Sweden. These systems supply the household electricity for single family houses. The aim was to evaluate the system costs, the cost of energy generated by the PV-Wind-Hybrid systems, the effect of the load size and to what extent the combination of these two energy sources can reduce the costs compared to a PV-alone system. The study has been performed with the simulation tool HOMER developed by the National Renewable Energy Laboratory (NREL) for techno-economical feasibility studies of hybrid systems. The results from HOMER show that the net present costs (NPC) for a hybrid system designed for an annual load of 6000 kWh with a capacity shortage of 10% will vary between $48,000 and $87,000. Sizing the system for a load of 1800 kWh/year will give a NPC of $17,000 for the best and $33,000 for the worst location. PV-Wind-Hybrid systems are for all locations more cost effective compared to PV-alone systems. Using a Hybrid system is reducing the NPC for Borlänge by 36% and for Lund by 64%. The cost per kWh electricity varies between $1.4 for the worst location and $0.9 for the best location if a PV-Wind-Hybrid system is used.

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The aim of the study is to develop a model for the energy balance of buildings that includes the effect from the radiation properties of interior and exterior surfaces of the building envelope. As a first step we have used ice arenas as case study objects to investigate the importance of interior low emissivity surfaces. Measurements have been done in two ice arenas in the north part of Sweden, one with lower and one with higher ceiling emissivity. The results show that the low emissivity ceiling gives a much lower radiation temperature interacting with the ice under similar conditions. The dynamic modelling of the roof in ice arenas shows a similar dependence of the roof-to-ice heat flux and the ceiling emissivity.A second part of the study focus on how to realise paints with very low thermal emissivity to be used on interior building surfaces.

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Development of an infrastructure for Brundtland Renewable Energy Network - BREN är ettEuropean Commission Alterner Project med Contract no XVII/4. 1030/Z96-032.Projektet har sitt ursprung i UN rapporten “Our Common Future” 1989. Grundläggande för att nå de mål som rapporten föreslog var att förändra och minska användningen av energi. I Danmark tog man fram en handlingsplan för hur energiförbrukningen skulle kunna minskas “Energi 2000 - Handlingsplan för en bäredygtig udvikling”. De danska och schleswigholstenske energiministrarna överenskom att starta vars ett energisparprojekt i en mindre stad. Projektet kallades “Brundtlandby” och de två första var Toftlund i Sönderjylland och Bredstedt i Nordfriesland. Efter en kort tid anslöt sig ytterligare två tyska städer, Rheinsberg och Viernheim, samt Rajec i Slovakien. Mellan städerna formades ett nätverk för att utbyta information. Nätverket, Brundtland City Project, var inspirerande för de ingående städerna i det fortsatta arbetet med energisparåtgärder. Brundtland City Project presenterades på en internationell konferens “Cities and Energy” i Trondheim, Norge, december 1995. Projektet väckte intresse och det föreslogs att nätverket, som ett pilotprojekt, skulle utvecklas i norra Europa för att senare utökas med andra europeiska länder. En ledningsgrupp tillsattes medrepresentanter från de nordiska länderna.En ansökan sändes till European Commission, Alterner Program, och denna beviljades i juli 1996. Projektet indelades i (9 Activities. Aktivitet 1, var att sammanfatta erfarenheterna av Brundtland City Project i Toftlund, Danmark och Brundtland Cities Nätverket i Sovakien, Tyskland och Danmark. Den nordiska delen startar med Aktivitet 2, vilket var att engagera kommuner/städer i Finland, Norge och Sverige. Som samordnade för den svenska delen utsågs Solar Energy Research Center SERC vid Högskolan Dalarna. Projektet presenterades vid ett seminarium den 30 september för representanter för Borlänge och Falu kommuner. Den 10 december 1996 accepterade de två kommunerna inbjudan att ingå i det nordiska nätverket. Uppgiftslämnare i Borlänge kommun har varit Pelle Helje, Borlänge Energi och i Falu kommun Anders Goop, stadsbyggnadskontoret samt för underlag till Newsletter Jan Kaans, fastighetskontoret.Rapportering till Brundtland Center Danmark av arbetet i Borlänge och Falu kommuner har skett vid tre tillfällen, Aktiviteterna 2-5, 1997-12-16, Aktivitererna 6-7 inkluderande delar av aktiviterna 8-9, 1998-05-03 samt underlag till Newsletter, 1998-07-01. De nordiska rapporterna har sammanställts vid Brundtland Center Danmark för rapportering till European Commission. Gemensamt språk har varit engelska. Efter rapportering av aktiviterna 2 - 5 inbjöds till ett projektmöte och en studiedag vid Brundtland Center den 23 och 24 mars 1998. Det var första tillfället deltagarna i projektet strålade samman och nätverket tog därmed en mera konkret form. Man beslutade också att nästa projektmöte skulle hållas i Borlänge i augusti 1998 med Borlänge Energi och Solar Energy Research Center SERC som organisatörer. Beroende på att Brundtland Centre Danmark upplösts av ekonomiska skäl blev projektmötet i Borlänge inställt.Sammanställning av Final Report, October 1998, har utförts av Esbensen Consultants.Framtida utveckling av nätverketArbetet med Brundtland City Network avses fortsätta som ett “EU Thermie B-project” och nätverket kommer att utökas med fyra nya Brundtlandstäder från Österrike, Tyskland Italien och Storbritanien. Dessutom kommer samhället Putja i Estland att ingå i nätverket men detta financieras av EU-Phare programme.

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Development of an infrastructure for Brundtland Renewable Energy Network - BREN is a European Commission Alterner Project with Contract no XVII/4. 1030/Z96-032.The project has its origin in the UN-report “Our Common Future”, 1989. A change in and reduction of the use of energy was fundamental in order to reach the goals which the report proposed. Denmark decided on an action plan on how energy consumption could be reduced “Energi 2000 - Handlingsplan för en bäredygtig udvikling”. The ministries of energy in Denmark and Schleswig Holstein both agreed to start an energy saving project in a smaller town. The project was called “Brundtlandby” and the two first were Toftlund in South Jutland and Bredstedt in North Friesland. After a short period a further two German Cities, Rheinsberg and Viernheim, and Rajec in Slovakia joined the group. A network for the exchange of knowledge and experience between the cities was formed. The network, Brundtland City Project, inspired the participating cities in the continuing work with energy saving measures. The Brundtland City Project was presented at an international conference “Cities and Energy” in Trondheim, Norway,in December 1995. Great interest was shown in the project and it was decided that a network should be developed in northern European countries as a pilot project to be enlarged with other European countries later on. A steering committee was formed with representatives from the nordic countries.An application was sent to the European Commission, Alterner Program, and was approved in Juli 1996. The project was subdivided into nine activities. Activity 1, consisted of summarising the experiences of the Brundtland City Project in Toftlund, Denmark and the Brundtland Cities network in Slovakia, Germany and Denmark. The Scandinavian part started with Activity 2, to engage municipalities/cities in Finland, Norway and Sweden in the project. The Solar Energy Research Center, SERC, Högskolan Dalarna was appointed as co-ordinator for the Swedish part. The project was presented at a seminar on the 30th September for representatives from the municipalities of Borlänge and Falun. On the 10th of December 1996 the two municipalities accepted the invitation to join the Northern network. Pelle Helje, Borlänge Energi, has been informant for the municipality of Borlänge and Anders Goop, Department of Urban Planninginformant for the municipality of Falun with Jan Kaans, Estates department providing information to the basis for the Newsletter.Reports on the work in Borlänge and Falun municipalities have been made to Brundtland Center Denmark on three occasions; Activities 2-5, 16-12-1997, Activities 6-7, including parts of activities 8-9, 03-03-1998, and the basis for the Newsletter, 01-07-1998. The Nordic reports have been compiled at the Brundtland Center Denmark for submission to the European Commission. English has been the common language. After the report of activities 2 - 5 the participants wereinvited to a project meeting and a workshop at Brundtland Center the 23rd and 24th March 1998.This was the first occasion the participants in the project met and the network thus took a moreconcrete form. It also was decided that the next meeting should be in Borlänge in August 1998,with Borlänge Energi and Solar Energy Research Center SERC as organisers. As BrundtlandCentre Denmark was wound up for financial reasons, the project meeting in Borlänge wascancelled.Compilation of the Final Report was carried out by Esbensen Consultants in October 1998Future development of the networkIt is intended to continue the work with the Brundtland City Network as an “EU Thermie Bproject”and the network will be enlarged with the addition of four new Brundtland Cities from Austria, Germany, Italy and Great Britain. In addition the village of Putja in Estonia will join the network but this will be financed by the EU-Phare programme.