The theme of the diploma thesis "Effect of energy care on building prices" is the design and assessment of several measures, two of which generally lead to lower heating costs. The diploma thesis deals with evaluation of the current state of the family house and determination of PENB before the construction modifications and subsequently after the construction modifications, defining subsequent measures for energy saving implementation, both in terms of energy, economic and also environmental.

In the process of hot rolling is roll surface thermo-mechanically stressed. To define lifetime of roll or to increase it by change of thermal mode, temperatures and forces acting on this roll need to be known. For this purpose should be used sensors, that are placed near by surface of roll. Aim of the first part of diploma thesis is to debug 2D computing model (MKP) to achieve the match of temperature graphs with experimentally measured values, which was recorded by temperature sensors in real process of rolling. In the second part the same temperature boundary conditions are applied on 3D model, which is used to solve mechanical strength check of the temperature sensor. The last part of thesis is design and verification of mechanical strength of the designed force sensor. The used boundary conditions were acquired in Laboratory of heat transfer and flow. The computing system ANSYS 11 is used to design a model of geometry and numerical calculation. This diploma thesis will be used as donating solution for the granted project, which started in this year with Laboratory of heat transfer and flow partnership.

This thesis deals with dependence of heat transfer coefficient on rate of air concentration in the water. Main idea appears from gas dissolvability in water depending on pressure, Henry's law and Newton's law of cooling. There had been an experiment made to verify the hypothesis.

This Ph.D. thesis is focused on theory and experimental investigations developing of new knowledge about polymeric hollow fiber heat exchanger (PHFHE). The state-of-the-art study of plastic heat exchangers shows that their usage is limited by several niches where their advantages significantly dominates, or where the use of non-plastic competitors is not impossible. On the other hand, plastic heat exchangers (and PHFHEs in particular) are devices of increasing interest. It is shown that use of small tubes (fibers) allows PHFHEs to be more competitive than conventional plastic heat exchangers. Small hydraulic diameter of a fiber causes high heat transfer coefficients, reduces thermal resistance of plastic wall and allows it to create light and compact design. Detailed study of fluid flow and heat transfer inside the hollow fiber showed that conventional approaches for single-phase laminar flow can be utilized. Poiseuille number equal to 64 and Nussel number about 4 are recommended to be used to predict pressure drops and heat transfer coefficient, respectively. Additional attention should be paid to careful determination of fiber diameter and liquid properties (viscosity). Scaling effects, such as axial heat conduction, thermal entrance region and viscous dissipation can be neglected. The study of outside heat transfer showed that heat transfer on fiber bunches are intense and are competitive to contemporary compact finned-tube heat exchangers. The Grimson approach showed clear correlation with experimental results and, thus is recommended to predict heat transfer coefficients on fiber bunches. Two types of fouling (particulate- and biofouling) of outer fiber surface were experimentally studied. It was found that particulate fouling by titanium oxide particles is not intense and deposits can be removed relatively easy. However, fouling is much more intense when it is associated with biofouling caused by wastewater. In this case, smooth and low-adhesive surface of plastic is not sufficient precaution to prevent deposit formation.

I dag sätts flera åtgärder in för att bromsa klimatförändringarna, både inom Sverige och på internationell nivå. ‘Forum för energieffektivt byggande’, FEBY, är en organisation som arbetar med att driva utvecklingen av lågenergibyggnader framåt. FEBY har tagit fram ett certifieringssystem som ska hjälpa byggherrar uppföra byggnader med lägre energianvändning. För att en byggnad ska bli certifierad krävs det att den uppfyller vissa krav, bland annat på värmeförlusttal. Sedan starten 2008 har ca 50 småhus certifierats enligt systemet, vilket väcker frågan om varför så få småhus har certifierats och om detta kan bero på hur kraven är ställda.Syftet med rapporten är att undersöka om de krav som FEBY ställer på värmeförlusttal är rimliga vid byggande av ett småhus oavsett vart i Sverige det är placerat. Undersökningen har gjorts för tre orter i olika delar av Sverige; Lund, Falun och Boden. Byggnadens utformning är densamma på alla tre orter, med undantag för isolertjocklek i ytterväggen. Parametrarna fönsterglasarea, U-värde på fönster, luftläckning och köldbrygga varierades i beräkningarna för att få ett bredare och mer trovärdigt resultat.Undersökningen görs enligt de beräkningar som FEBY hänvisar till i dokumentet FEBY18 med utgångspunkt i krav för värmeförlusttal på nivå FEBY Guld.Rapporten avgränsas till en enplansvilla på 100 m2 uppvärmd golvarea. Ingen hänsyn tas till faktorer så som ljud, sol, fukt, årsvärmefaktor eller värmebalans för luftvärmd byggnad. Inte heller beaktas bärförmåga, motstånd mot brand eller fönstrens läge.Resultatet visar att negativa U-värden uppstår vid flera parametervariationer i Boden och Falun. Negativa U-värden indikerar att ytterväggen måste producera värme, vilket i det här fallet inte är möjligt. I flera fall i Falun och Boden förekommer även så pass låga U-värden att isoleringen behöver anta en tjocklek på över en meter medan isolertjockleken i Lund aldrig överstiger 500 mm. Vid de mest gynnsamma förutsättningarna visar resultatet att det fortfarande är svårt att nå en rimlig isolertjocklek, eller ett positivt U-värde, i Boden och delvis Falun.Slutsatsen är att det går att konstruera en byggnad som når kraven för nivå FEBY Guld i södra Sverige, men att det blir svårare ju längre upp i landet som byggnaden ska uppföras. Tjockare isolering verkar inte göra kraven uppnåeliga i Sveriges norra delar utan med de förutsättningar som undersöks skulle väggen behöva skapa värme om värmeförlusttalet för FEBY Guld ska nås. / In the current political climate, several measures are implemented to prevent climate change both in Sweden and internationally. ‘Forum för Energieffektict Byggande’, FEBY, is an 6rganization that aims to contribute to the development and expansion of low-energy buildings. To this end, FEBY has created a certification scheme to help contractors develop buildings with lower energy consumption. To certify a building, the contractor must ensure that certain requirements are met, for example heat loss figures. Since the conception of the certification, only about 50 small houses have been certified. This raises the question of why so few small houses have been certified, and whether this is due to how the requirements are set.The purpose of this report is to investigate whether the heat loss figures that features in FEBY’s certification are reasonable in reference to the construction of small houses regardless of its location in Sweden. To examine this, this study features small house construction in Lund, Falun, and Boden. The overall building design is the same in all three locations, apart from the insulation thickness in the outer wall. The examined parameters for this study include window glass area, U-value of windows, air leakage, and thermal bridges varied in the calculations to ensure a more relevant and reliable result.This study is based on the calculations referred to in the document named FEBY18 which is based on the requirements for heat loss figures according to the FEBY Gold level.The report is limited to a single-floor house of 100 m2 of heated floor area. Factors such as sound, sun, moisture, annual heat factor, or heat balance for air-heated buildings are not considered. Nor is bearing capacity, resistance to fire, or the position of the windows, considered within the study.The result shows that negative U-values occur in several parameter variations in Boden and Falun. Negative U-values indicate that the outer wall must produce heat, which is not possible due to the construction of the wall. In several cases in Falun and Boden the U-values were so low that the insulation would need a thickness of more than one meter, while the insulation thickness in Lund never has to exceed 500 mm. Even during the most favorable conditions, the results still show the difficulty of achieving reasonable insulation thickness, as well as a positive U-value. This is especially true with regards to Boden, but in part also Falun.In conclusion, while it is possible to construct a small house that meet the requirements for the level FEBY Gold in the south of Sweden, it is increasingly challenging the further north you attempt to construct such a building. Even using thicker insulation, the requirements are difficult, if not impossible, to achieve in the north of Sweden. Under current conditions, the wall would need to generate its own heat to meat the heat loss figure demanded by the FEBY Gold standard.

I dagens samhälle ligger stort fokus på att bygga miljövänliga och energieffektiva byggnader. För att möta de allt mer skärpta energikraven måste hela klimatskalet beaktas där köldbryggor utgör en betydande del. Examensarbetet går ut på att göra en sammanställning av linjära köldbryggor (ψ) för vanligt förekommande konstruktionsdetaljer där köldbryggor finns. Sammanställningen där olika isoleringsmaterial på fasadskiva och isolertjocklekar tabelleras, ska underlätta för framtida projektering. Två simuleringsprogram för beräkning av köldbryggor har jämförts och utvärderats med varandra. Utvärderingen har gjorts med avseende på vilket program som var mest lämpat för att lösa frågeställningen. De två simuleringsprogrammen som används vid detta arbete är HEAT2 och COMSOL Multiphysics. Arbetet har resulterat i en lathund som finns tillgänglig på ELU:s intranät. Lathunden innehåller U-värde och ψ-värde med illustrering av konstruktionsdetaljerna och i detta arbete redovisas tillvägagångssätt och utförandet. En utvärdering av det lämpligaste program för utförandet av uppgiften finns också redovisad. / Currently there is a lot of focus on environmentally friendly and energy efficient buildings in our society. To face the more toughen energy requirements, the entire climate shell of the building has to be considered there thermal bridges constitute a significant part. This bachelor dissertation intends to create a compilation for Ψ-values of common construction details where thermal bridges are to be found. The compilation with a chart that includes insulating material and insulation thickness shall simplify in future projecting. Furthermore, two simulating programs for calculations of thermal bridges have been compared with each other. The two simulation programs that have been used in this dissertation are HEAT2 and COMSOL Multiphysics. This dissertation has resulted in a quick reference guide which is available at ELU`s internal network. This quick reference guide includes U-values and Ψ-values with an illustration of every construction detail and the procedure and execution is reported in this dissertation. An evaluation of which of the two programs that has been used was more appropriate for this purpose is presented as well.

This thesis investigates the cooling behaviour of polymers during the microinjection moulding process. The work included bespoke experimental mould design and manufacturing, material characterisation, infra-red temperature measurements, cooling analysis and cooling prediction using commercial simulation software. To measure surface temperature of the polymers, compounding of polypropylene and polystyrene with carbon black masterbatch was performed to make materials opaque for the IR camera. The effects of addition of carbon black masterbatch were analysed using differential scanning calorimetry and Fourier transform infrared spectroscopy. Sapphire windows formed part of the mould wall and allowed thermal measurements using an IR camera. They were laser machined on their inside surfaces to generate a range of finishes and structures. Their topographies were analysed using laser confocal microscope. The surface energy of sapphire windows was measured and compared to typical mould steel, employing a contact angle measurement technique and calculated using Owens-Wendt theory. A heating chamber was designed and manufactured to study spreading of polymer melts on sapphire and steel substrates. A design of experiments approach was taken to investigate the influence of surface finish and the main processing parameters on polymer cooling during microinjection moulding. Cooling curves were obtained over an area of 1.92 by 1.92 mm of the sapphire window. These experiments were conducted on the Battenfeld Microsystem 50 microinjection moulding machine. A simulation study of polymer cooling during the microinjection moulding process was performed using Moldflow software. Particular interest was paid to the effect of the values of the interfacial heat transfer coefficient (HTC) on the simulated cooling predictions. Predicted temperature curves were compared to experimentally obtained temperature distributions, to obtain HTC values valid for the material and processing parameters.

No description available.

The work presented in this dissertation is the first numerical investigation conducted to study leading edge film cooling with Large Eddy Simulation (LES). A cylindrical leading edge with a flat after-body represents the leading edge, where coolant is injected with a 30Ë compound angle. Three blowing ratios of 0.4, 0.8, and 1.2 are studied. Free-stream Reynolds number is 100,000 and coolant-to-mainstream density ratio is unity. At blowing ratio of 0.4, the effect of coolant inlet condition is investigated. Results show that the fully-turbulent coolant jet increases mixing with the mainstream in the outer shear layer but does not influence the flow dynamics in the turbulent boundary layer at the surface. As a result, the turbulent jet decreases adiabatic effectiveness but does not have a substantial effect on the heat transfer coefficient. At B.R.=0.4, three types of coherent structures are identified which consist of a primary entrainment vortex at the leeward aft-side of the coolant hole, vortex tubes at the windward side of the coolant hole, and hairpin vortices typical of turbulent boundary layers produced by the turbulent interaction of the coolant and mainstream downstream of injection. At B.R. = 0.8 and 1.2, coherent vortex tubes are no longer discernable, whereas the primary vortex structure gains in strength. In all cases, the bulk of the mixing occurs by entrainment which takes place at the leeward aft-side of the coolant jet. This region is characterized by a low pressure core and the primary entrainment vortex. Turbulent shear interaction between coolant jet and mainstream increases substantially with blowing ratio and contributes to the dilution of the coolant jet. As a result of the increased mixing in the shear layer and primary structure, adiabatic effectiveness decreases and heat transfer coefficient increases with increase in blowing ratio. The dissertation also investigates the deposition and erosion of Syngas ash particles in the film cooled leading edge region. Three ash particle sizes of 1, 5, and 10 microns are investigated at all blowing ratios using Lagrangian dynamics. The 1 micron particles with momentum Stokes number St = 0.03 (based on approach velocity and cylinder diameter), show negligible deposition/erosion. The 10 micron particles, on the other hand with a high momentum Stokes number, St = 3, directly impinge and deposit on the surface, with blowing ratio having a minimal effect. The 5 micron particles with St=0.8, show the largest receptivity to coolant flow and blowing ratio. On a mass basis, 90% of deposited mass is from 10 micron particles, with 5 micron particles contributing the other 10%. Overall there is a slight decrease in deposited mass with increase in blowing ratio. About 0.03% of the total incoming particle energy can potentially be transferred as erosive energy to the surface and coolant hole, with contribution coming from only 5 micron particles at B.R.=0.4 and 0.8, and both 5 and 10 micron particles at B.R.=1.2. / Ph. D.

Complex or smart fluids, made of evenly and stably suspended nanoparticles, have been an object of considerable research in the last decade due to their promising applications in a number of applications such as micro-electronic cooling, high power demands in nuclear plants, smaller and more efficient heat exchangers, oil recovery, and transportation. Nanofluids consist of typically less than 100nm sized particles dispersed in base fluids. The heat transfer characteristics of several nano-oxide suspensions in pool boiling with a suspended heating NiChrome wire have been analyzed. The pH value of the nanosuspensions is important from the point of view that it determines the stability of the particles and their mutual interactions towards the suspended heated wire. Heat transfer in silica nanofluids at different acidity and base is measured for various ionic concentrations in a pool boiling experiment. Nanosilica suspension increases the critical heat flux by up to 300% compared to conventional fluids. The l0 nm particles possess a thicker double diffuse layer compared to 20 M particles. The catalytic properties of nanofluids decrease in the presence of salts, allowing the particles to cluster and minimize the potential increase in heat transfer. Nanofluids in a strong electrolyte, i.e., in high ionic concentration, allow a higher critical heat flux than in buffer solutions because of the difference in surface area. The formation and surface structure of the deposition affect the thermal properties of the liquid. When there is no particle deposition on the wire, the nanofluid increases CHF by about 50% within the uncertainty limits, regardless of pH of the base fluid or particle size. The extent of oxidation on the wire impacts CHF, and is influenced by the chemical composition of nanofluids in buffer solutions. The boiling regime is further extended to higher heat flux when there is agglomeration on the wire. This agglomeration allows high heat transfer through inter-agglomerate pores, resulting in a nearly 3-fold increase in burnout heat flux. The pool boiling heat transfer has been even higher (- up to 4 times that of the base fluid) for Double Walled Carbon Nanotubes (DWNTs). A comparison study between Single and Double Walled Carbon Nanotube suspensions has been performed. A closed flow loop has been designed and fabricated to study the thermal transport characteristics of nanosilica suspensions in heated flow. The heat transfer coefficient and pressure drop data are provided for laminar and turbulent regimes (2000