• Energy Research
• Restricted close
• Open Source close

The possibility to increase human comfort and reduce the global footprint of buildings is a powerful driving force for introduction of new building technology. Here advanced coating technologies pl ...

Abstract A unique large scale pilot plant of the CellFlux thermal energy storage concept is experimentally investigated. This storage concept consists of a regenerator type thermal energy storage volume, which is coupled to a finned tube heat exchanger by a circulating intermediate working fluid. The system investigated in this work operates at a temperature of 390 °C and uses air as intermediate working fluid which is conveyed by a centrifugal fan. The storage volume has a bed length of over ten meters and is of a novel design, where the air flows in horizontal direction. Since this approach could cause a flow maldistribution, a thorough analysis is of major interest for the accuracy of subsequent numerical simulations. The experiments reveal that the mass flow along the centerline can be up to 20% higher than the mean bulk flow. A significant maldistribution between top and bottom area, however, is not observed. As an alternative to the typically used rock filling, the storage volume is equipped with standard hollow bricks. These bricks are cost effective but do not have a well-defined shape. Thus, the predictability of the pressure drop by correlations found in the literature is unclear. It turns out that the measured pressure drop is evenly distributed in axial flow direction but generally higher than expected from the assumption of pure channel flow. Further experiments are conducted to validate the heat capacity of the bricks and to derive a correlation for the inner heat transfer between bricks and storage walls. Eventually, the aim of the experimental investigation is a general proof of concept as basis for the numerical investigation. Thus, all specifications of the plant and the storage material are provided. The plant is analyzed towards plausibility of heat losses, showing that heat losses can be predicted well within the given uncertainties.

Environment preservation, energy, and the growing economy are becoming strongly interconnected themes requiring new solutions to be exploited. An example of this interconnection is the demand for the development of almost zero-energy buildings, i.e. buildings capable to be almost autonomous from external energy supply or at least not dependent on the energy supply from utilities. The actual conception of a zero energy building is a very complex system formed by several subsystems, with the consequence that costs are very high and reliability relatively low. The aim of this research program is to deepen the possibility to employ the Stirling engine and cooler technology to lower the number of components required in a near zero-energy building, increase the efficiency, and contemporary raise the reliability of the overall system. Stirling cooler could be used to convert mechanical work into heating and cooling effects and produce the temperature difference by the expanding and compressing the working fluid. A similar concept of the Stirling cooler could also be adopted to develop a heat pump. Compared to the traditional vaporcompression refrigeration systems, the Stirling coolers are of higher efficiency and with no components like compressor, expansion valve, evaporator, or condensers. Therefore, they are considered to be clean cooling devices. On the other hand, the Stirling engine is an external combustion engine, which is compatible with a variety of thermal sources, such as solar radiation, waste heat, geothermal energy, combustion, and so on. With the heat input to the hot end of the engine, the Stirling engine could be operated to produce mechanical work/electricity at high thermal efficiency. In principle, the Stirling machines are capable to provide all the forms of energy (heat, cool, and electricity) that form the almost total energy load of a building.

Explaining variation in life history phenology requires us to disentangle environmental-dependent variability from that caused by adaptive change across time and space. Here, we offer thermal time models (models measuring time in temperature units) as tools to understand the spawning dynamics of small pelagic fish, such as Pacific herring Clupea pallasii. We hypothesised that thermal time explains the annual timing of spawning of Pacific herring across space and time. By testing this hypothesis, we identified developmental constants (thermal constants of spawning) that can be used to make spawning time predictions. We examined spatio-temporal changes in Pacific herring spawning time over a 69 yr period (1941-2010) across 6 regions off British Columbia (BC), Canada. We estimated the degree-days (DD, °C-days) from the onset of gonadal maturation to spawning by combining spawning time estimates with distribution-specific temperature estimates. We then fitted models to explore how DD to spawning can be used to explain observed spawning time patterns across space and time and identified temperature-independent sources of variability (e.g. adaptive differences among regions, spawner size). We found that, even though Pacific herring often spawned ∼5 d later with each increasing degree in latitude, the average thermal time in DD to spawning was ∼1700°C-days. We also found that DD to spawning explains linear variation in spawning time across years for some regions of the BC Pacific herring. Thermal time models can aid in predictions of environmental responses and forecasts of life-history phenology in a changing climate.

AbstractDendronic antennae systems containing pyrene units as energy donors and a styrylpyridinium derivative as energy acceptor show efficient energy transfer from the green‐emitting pyrene excimer to the red‐emitting acceptor. For the third dendron generation the effective screening of the pyrene units on the acceptor provides thin films showing bright red emission. Single‐layer light‐emitting diodes prepared by properly balancing the dendrons and donor units concentration in polyvinylcarbazole show electroluminescence from the blue, green and red components of the monomeric donor, the donor excimer and the acceptor when excitons are generated in the polymer and subsequently transferred to the molecules by resonant energy transfer.

Rapporten beskriver hvordan solvægge kan implementeres i programmer til beregning af bygningers energi- og temperaturforhold, med tsbi3 (edb-program til termisk simulering af bygninger og installationer) som et konkret eksempel. Der opstilles løsninger for nogle af de processer, som har størst betydning for en korrekt beregning af solvægge. Rapporten henvender sig til rådgivende ingenører, der beskæftiger sig med solvægge, og giver en mere dybtgående beskrivelse af tsbi3 til beregning af solvægge end brugervejledningen.

The master thesis covers the design of a photovoltaic solar power plant for a selected family house in Ústašice in Tábor’s region The theoretical part summarizes the photovoltaic phenomenon, production, and differences of various technologies of photovoltaic panels and different types of battery storages. The project also includes the legislative and subsidy conditions in the Czech Republic related to the PV topic. The practical part of the thesis starts with information about the layout of the family house with an analysis of household consumption data for the last five years. The analysis is followed by the selection of a suitable type of system for photovoltaic water heating. Using multi-criteria analysis, the most suitable solar controller and PV panels are then selected. The proposed system is updated with other necessary components. Finally, a simulation of the system is created in PV*SOL to determine the lighting conditions and to evaluate the economics side of the entire project. Diplomová práce se zabývá návrhem fotovoltaické solární elektrárny pro vybraný rodinný dům v lokalitě Ústrašice na Táborsku. Teoretická část shrnuje problematiku fotovoltaického jevu, výrobu a rozdíly jednotlivých technologií pro fotovoltaické panely a různé druhy bateriových úložišť. Součástí práce jsou také legislativní a dotační podmínky v České republice spojené s problematikou FVE. V úvodu praktické části práce jsou obsaženy informace o dispozicích rodinného domu s analýzou dat spotřeby domácnosti za posledních pět let. Na analýzu navazuje výběr vhodného typu soustavy pro fotovoltaický ohřev vody. Za použití multikriteriální analýzy jsou následně zvoleny nejvhodnější regulátor a FV panely. Navržený systém je přehledně doplněn o další potřebné komponenty. V závěru je v programu PV*SOL vytvořena simulace systému pro stanovení světelných podmínek a vyhodnocení hospodárnosti celého projektu. A

Objective The current guidelines suggest alcohol septal ablation (ASA) is less effective in hypertrophic obstructive cardiomyopathy (HOCM) patients with severe left ventricular hypertrophy, despite acknowledging that systematic data are lacking. Therefore, we analysed patients in the Euro-ASA registry to test this statement. Methods We compared the short-term and long-term outcomes of patients with basal interventricular septum (IVS) thickness <30 mm Hg to those with ≥30 mm Hg treated using ASA in nine European centres. Results A total of 1519 patients (57±14 years, 49% women) with symptomatic HOCM were treated, including 67 (4.4%) patients with IVS thickness ≥30 mm. The occurrence of short-term major adverse events were similar in both groups. The mean follow-up was 5.4±4.3 years and 5.1±4.1 years, and the all-cause mortality rate was 2.57 and 2.94 deaths per 100 person-years of follow-up in the IVS <30 mm group and the IVS ≥30 mm group (p=0.047), respectively. There were no differences in dyspnoea (New York Heart Association class III/IV 12% vs 16%), residual left ventricular outflow tract gradient (16±20 vs 16±16 mm Hg) and repeated septal reduction procedures (12% vs 18%) in the IVS <30 mm group and IVS ≥30 mm group, respectively (p=NS for all). Conclusions The short-term results and the long-term relief of dyspnoea, residual left ventricular outflow obstruction and occurrence of repeated septal reduction procedures in patients with basal IVS ≥30 mm is similar to those with IVS <30mm. However, long-term all-cause and cardiac mortality rates are worse in the ≥30 mm group.

In bioreactors used for the purification of wastewater, microorganisms are active in biofilms or aggregates. Insight into the factors that determine the structure and function of aggregated biomass is increasing steadily. Besides conventional techniques, modem molecular techniques are used increasingly to get a better understanding of the complex microbial communities in wastewater treatment systems. In recent years, the combined use of these techniques has led to a good insight into the population dynamics of different types of microbes in bioreactors.