A home for elderly is planed to be built at Zakrisdal, Karlstad, Sweden. The heat source for the building was at the time not determined. In order by the local government of Karlstad this report is meant to examine if the need of heat could be provided only by solar heat combined with a seasonal heat storage. The problem to solve is, if the need of heat from the home for elderly is provided from only solar heat, whitch dimensions of the solar collectors and the storage is needed?

The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Title from PDF of title page (University of Missouri--Columbia, viewed on February 12, 2010). Thesis advisor: Dr. Galen J. Suppes. Includes bibliographical references.

published_or_final_version / Mechanical Engineering / Master / Master of Philosophy

No description available.

Large percentages of the South African population have no access to grid power and are located at distances that make provision for such facility uneconomical. Also traditional fuels are under pressure. Most areas in South Africa receive 300 days of sunshine per year. The proposed solar system addresses the needs of such communities. A solar thermal energy storage system utilizing phase change material has been proposed that can overcome the time mismatch between solar availability and demand. The system consists of two types of thermal heat storage. The latent heat storage used Phase Change Materials (PCM) which melts at a sufficiently high temperature for cooking a variety of food types. By choosing a suitable PCM to take advantage of the latent heat absorbed during phase changes. Heat losses from both the latent heat storage and condenser are captured in the surrounding sensible heat store. The objective of this project to develop a prototype modules which together as a system could provide the essential domestic power requirements of the target groups. This includes power for cooking, hot water and in addition a limited electrical power supply for the system itself as well as for other minor loads. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2008.

Ett vanligt problem för fjärrvärmeföretag är svängningar i den dagliga efterfrågan på fjärrvärme. När efterfrågetoppar sker i fjärrvärmenätet behöver fjärrvärmeföretagen oftast använda sina topplastpannor, vilka vanligtvis drivs på både dyra och miljöovänliga bränslen. Ett sätt att åtgärda detta problem har traditionellt varit att använda en ackumulatortank som värmelager. Men med ny och billigare mät- och styrsystemteknik har kommersiella lösningar börjat växa fram där istället byggnader kan användas som värmelager. Syftet med examensarbetet är att undersöka de tekniska och ekonomiska möjligheterna för att använda byggnader som värmelager i ett fjärrvärmesystem och jämföra det med att använda en ackumulatortank som värmelager. Det förs en diskussion om hur ett samarbete skulle kunna se ut mellan fjärrvärmeföretag och fastighetsägare för att möjliggöra användningen av byggnader som värmelager. I examensarbetet genomförs en litteraturstudie och intervjuer för att både beskriva hur byggnader kan användas som värmelager och att beskriva intressenterna och deras relation. Det utförs även en fallstudie på Hudiksvalls fjärrvärmenät. I fallstudien används produktionsdata från Hudiksvalls fjärrvärmeproduktion och en analys utförs med hjälp av MATLAB och Microsoft Excel. I analysen besvaras frågan om hur stora kostnadsbesparingar och intäktsökningar som skulle kunna uppnås ifall Hudiksvalls fjärrvärmenät fick tillgång till värmelager i olika storlekar. Utifrån dessa kostnadsbesparingar och intäktsökningar görs en investeringsanalys. I investeringsanalysen jämförs de två alternativen för värmelager, det vill säga att använda byggnader som värmelager eller en ackumulatortank som värmelager. Utifrån de teoretiska studierna och fallstudien på Hudiksvalls fjärrvärmenät kan följande slutsatser dras: En investering i att använda byggnader som värmelager har en högre avkastning per investerad krona och kortare återbetalningstid än en investering i att använda en ackumulatortank. Skillnaderna är som störst vid små värmelager och minskar vid större storlek på värmelager. Detta beror på att den initiala investeringskostnaden för att använda byggnader som värmelager är lägre än den initiala investeringskostnaden för att använda en ackumulatortank som värmelager. En investering i att använda byggnader som värmelager har ett högre nettonuvärde vid små värmelagerstorlekar än en investering i att använda en ackumulatortank som värmelager. Men vid större storlekar på värmelagret ger en investeringen i en ackumulatortank ett högre nettonuvärde. Byggnader kan användas som värmelager utan att varken inomhuskomforten försämras nämnvärt eller att energiförbrukningen höjs beaktansvärt. Energiförbrukningen kan till och med sänkas ifall ett nytt värmestyrsystem installeras i en byggnad som ersätter ett äldre mindre effektivt värme-styrsystem. Både pengar och tid kan sparas ifall det redan finns en god relation mellan fjärrvärmeföretag och fastighetsägare, när byggnader ska användas som värmelager. Det mest fördelaktiga valet mellan att investera i byggnader som värmelager eller en ackumulatortank som värmelager skiftar alltså från fall till fall och inget av alternativen är alltid det bästa. För att ta ställning till vilken teknik som ska användas som värmelager behöver en analys göras för varje enskild situation. / A common problem for district heating companies is fluctuations in the daily demand for district heating. When peak demand occurs in the district heating network the district heating companies usually needs to use their peak load boilers, which are operated on both expensive and not sustainable fuels. One way to overcome this problem has traditionally been to use a storage tank as heat storage. But with new and cheaper measurements and control system technology has commercial solutions begun to emerge in which buildings can be used instead as heat storage. The aim of the thesis is to investigate the technical and economic feasibility of buildings as heat storage in a district heating system and compares it with the use of a storage tank as heat storage. There has also been a discussion of how collaboration might look like between the district heating company and the property owners to permit the use of buildings as heat storage. A literature review and interviews are conducted in the thesis in order to both describe how buildings can be used as heat storage and describe the stakeholders and their relationship. A case study is also carried out at Hudiksvall’s district heating network. The case study use production data from Hudiksvall’s district heating production and an analysis is carried out using MATLAB and Microsoft Excel. The analysis answers the question of how large cost savings and revenue increases that could be achieved if the district heating network had access to heat storage on various scales. Based on the cost savings and revenue increases, an investment analysis is carried out. In the investment analysis the two options, buildings as heat storage and storage tank as heat storage, are compared. Based on the theoretical studies and the case study at Hudiksvall’s district heating network it can be concluded that: An investment to use buildings as heat storage has a higher return per dollar invested and a shorter payback time than an investment to use a storage tank as a heat store. The differences are greatest for small size heat storages and approaching each other for large size heat storages. This is due to the lower initial investment cost when using buildings as heat storage compared to when using storage tanks as heat storage. An investment to use buildings as heat storage has a higher net present value for small heat storages compared to an investment to use a storage tank as heat storage. But for larger heat storage sizes an investment in storage tanks has a higher net present value. Buildings can be used as heat storage without a significant decrease in indoor comfort or a noteworthy increase in energy consumption. The energy consumption can even be reduced if a new heating control system is installed in a building to replace an older less efficient heat control system. Both money and time can be saved if there is already a good relationship between the district heating companies and the property owners, when the buildings should be used as heat storage. The best option for choosing between using buildings or a storage tank as heat storage depends on the situation and none of the options are always best. In order to decide which technology should be used as heat storage an analysis is required for each individual case.

Thesis (Ph. D.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on March 20, 2009) Vita. Includes bibliographical references.

Thesis (M.S.)--University of Nevada, Reno, 2008. / "December 2008." Includes bibliographical references (leaves 58-59). Online version available on the World Wide Web.

No description available.

Orientador: Kamal Abdel Radi Ismail / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-20T09:32:00Z (GMT). No. of bitstreams: 1 Moraes_RaykleisonIgordosReis_D.pdf: 4245831 bytes, checksum: 07427cc907cc6cf8690c510c3dd14a1c (MD5) Previous issue date: 2012 / Resumo: O presente trabalho consiste na investigação numérica e experimental do carregamento de um leito fixo com material de mudança de fase no interior das cápsulas esféricas. O modelo matemático é baseado na equação da energia e a solução obtida com a técnica numérica em diferenças finitas com o esquema da malha móvel. O acoplamento do fluido de trabalho com as cápsulas foi feita utilizando o balanço de energia com o material de mudança de fase, obtendo a temperatura em função do tempo e da posição no leito. O modelo desenvolvido mostra os efeitos da temperatura de entrada, vazão mássica, diâmetro da cápsula esférica, material das cápsulas, tempo de carregamento e altura do armazenado. A Validação e otimização dos resultados foi feita com base nos resultados experimentais apresentados. As equações empíricas apresentadas podem ser ferramentas úteis como forma alternativa nos projetos de armazenadores com erro médio de ± 11% e a incerteza nos dados experimentais para a temperatura é de ± 0,5oC. Todos os resultados são analisados e discutidos / Abstract: The present work is to investigate numerical and experimental and the charging of fixed bed PCM within the spherical capsules. The mathematical model is based on the energy equation and the solution obtained with the numerical technique of finite difference scheme with mesh mobile. The coupling of the working fluid with the capsules was conducted using the energy balance of the phase change material, obtaining the temperature versus time and bed position. The model shows the effects of the inlet temperature, mass flow rate, diameter of the spherical capsule, the capsule material, charging time and the stored height. Validation and optimization of the results was based on experimental results. The empirical equations presented can be useful tools as an alternative projects in storages with average error of 11% and the uncertainty of the experimental data for temperature is 0.5oC. All results are analyzed and discussed / Doutorado / Termica e Fluidos / Doutor em Engenharia Mecânica