Thermoelectric generator for flue-gas duct of boiler to convert low-temperature waste heat to electricity

S tenčící se zásobou fosilních paliv, roste zájem o co možná nejefektivnějšího využívání primárních zdrojů energie. V celé řadě dnešních zařízení odchází značná část energie paliva nevyužita v podobě odpadního tepla. Jako vhodné dílčí řešení se ukazují aplikace s termoelektrickým generátorem, čili zařízením přímo přeměňující tepelnou energii na energii elektrickou. Tento trend v posledních letech dokazuje rostoucí zájem o tuto technologii a vývoj nových termoelektrických materiálů. Krom zmíněného využití odpadního tepla lze termoelektrické generátory nalézt v řadě dalších aplikací, především jako zdroje elektrické energie v podmínkách, kde jsou vyžadovány minimální nároky na údržbu, bezporuchovost, spolehlivost a dlouhou životnost. Text práce je rozdělen do tří částí: teoretické části, části zabývající se návrhem a realizací generátoru a závěrečným zhodnocení. Teoretická část obsahuje popis základních termoelektrických jevů, termoelektrických materiálů a jejich vlastností, popis hlavních komponent termoelektrických generátorů a aplikace, v nichž se termoelektrická přeměna využívá. Část návrhu a realizace se zabývá návrhem termoelektrického generátoru pro spalinový tah kotle a porovnání hodnot návrhu s reálnými naměřenými hodnotami.With the dwindling supply of fossil fuels is increasing interest in the most efficient use of primary energy sources. In many of today's devices leaving a considerable part of the fuel energy wasted in the form of waste heat. As a partial solution suitable to demonstrate the application of thermoelectric generator, or devices that convert heat energy directly into electrical energy. The trend in recent years shows the growing interest in this technology and the development of new thermoelectric materials. In addition to the use of waste heat thermoelectric generators can be found in a number of other applications, primarily as a source of electricity in conditions where required minimal maintenance, reliability, reliability and durability. Text is divided into three parts: a theoretical part, the part dealing with the design and implementation of the generator, and a final evaluation. The theoretical part includes a description of the basic thermoelectric phenomena, thermoelectric materials and their properties, a description of the main components of thermoelectric generators and applications in which the thermoelectric conversion uses. Part of the design and implementation deals with the design of thermoelectric generator for chimney flue and comparison of the proposal with real measured values.

Steam Turbine for fossil power plant

Diplomová práce se věnuje návrhu kondenzační parní turbíny spalující fosilní paliva o jmenovitém výkonu na svorkách generátoru 250 MW s přihříváním páry a osmi neregulovatelnými regeneračními odběry. Turbína se skládá ze dvou těles, kombinovaného vysoko-středotlakého dílu a nízkotlakého dílů s dvouproudým výstupem dolů do vodou chlazeného kondenzátoru. Práce obsahuje výpočet tepelného schématu pro 100% a 75% výkon, výpočet měrné spotřeby tepla a návrh průtočné části VT-ST dílu. Dále pevnostní kontrolu a základní konstrukční návrh vysoko-středotlakého dílu doplněný o podélný řez. Dosažené výsledky jsou ke konci práce porovnány s úlohou 3a a v závěru práce shrnuty výhody a nevýhody koncepce s kombinovaným vysoko-středotlakým dílem oproti středo-nízkotlakému dílu.This thesis deals with design is condensing steam turbines burning fossil fuels with nominal capacity of the generator of 250 MW with steam reheating and regenerative eight uncontrolled extraction points. The turbine consists of two bodies: a combined high-intermediate pressure section and low pressure parts with dual way outlet down into the water-cooled condenser. Work includes calculating thermal scheme for 100% and 75% capacity, specific heat consumption calculation and design of the flow HP-MP body. Further strength control and basic engineering design of high-medium- work completed by longitudinal section. Achievements are at the end of work compared with work 3a and the conclusion summarizes the advantages and disadvantages of the concept.

Steam Turbine for fossil power plant

Diplomová práce se věnuje návrhu kondenzační parní turbíny spalující fosilní paliva o jmenovitém výkonu na svorkách generátoru 250 MW s přihříváním páry a osmi neregulovatelnými regeneračními odběry. Turbína se skládá ze dvou těles, kombinovaného vysoko-středotlakého dílu a nízkotlakého dílů s dvouproudým výstupem dolů do vodou chlazeného kondenzátoru. Práce obsahuje výpočet tepelného schématu pro 100% a 75% výkon, výpočet měrné spotřeby tepla a návrh průtočné části VT-ST dílu. Dále pevnostní kontrolu a základní konstrukční návrh vysoko-středotlakého dílu doplněný o podélný řez. Dosažené výsledky jsou ke konci práce porovnány s úlohou 3a a v závěru práce shrnuty výhody a nevýhody koncepce s kombinovaným vysoko-středotlakým dílem oproti středo-nízkotlakému dílu.This thesis deals with design is condensing steam turbines burning fossil fuels with nominal capacity of the generator of 250 MW with steam reheating and regenerative eight uncontrolled extraction points. The turbine consists of two bodies: a combined high-intermediate pressure section and low pressure parts with dual way outlet down into the water-cooled condenser. Work includes calculating thermal scheme for 100% and 75% capacity, specific heat consumption calculation and design of the flow HP-MP body. Further strength control and basic engineering design of high-medium- work completed by longitudinal section. Achievements are at the end of work compared with work 3a and the conclusion summarizes the advantages and disadvantages of the concept.

Changes in fatty acid profile and iodine content in milk as influenced by the inclusion of extruded rapeseed cake in the diet of dairy cows

The aim of the study was to evaluate the effect of extruded rapeseed cake in diets of dairy cows on changes in milk fatty acid profile and iodine content in milk and on the thyroid gland status. An experiment was carried out on four lactating Holstein cows divided into 2 groups - experimental (R) fed a diet based on extruded rapeseed cake and control (S) fed a diet based on extruded full-fat soya. The experiment was divided into 4 periods of 42 days (21 days of preliminary period and 21 days of experimental period). Samples of milk and blood were taken three times a week during the experimental period. DMI was not affected by the treatment (P > 0.05). Milk yield and 4% FCM were lower in R compared to S (P 0.05). However, the content of MUFA in R was higher (34.71 g/100 g) and the content of PUFA was lower (4.00 g/100 g) than in S (32.14 and 5.54 g/100 g, respectively (P 0.05). The mean daily intake of glucosinolates (Gls) in R was 50.14 mmol and resulted in a significant decrease in iodine concentration in milk in R (196.7 mu g/l) in comparison with S (367.0 mu g/l, P 0.05)

Comparison of Maize Silage-based Diets for Dairy Cows Containing Extruded Rapeseed Cake or Extruded Full-fat Soybean as Major Protein Sources

The trial was carried out on four Holstein cows with initial milk yield of 27.3 ± 1.7 kg.day−1. Cows were divided into two groups – the first was fed a diet based on extruded rapeseed cake (D-ERC), the second one was fed a diet based on extruded full-fat soybean (D-EFFS), both diets contained maize silage and meadow hay. The experiment was divided into 4 periods of 42 days. Intake of dry matter, crude protein and NEL was not affected by the treatment (P > 0.05) while the intake of PDIA, PDIN and PDIE was lower in D-ERC than in D-EFFS (P < 0.05). Milk yield in D-ERC (22.6 kg.d−1) was lower than in D-EFFS (24.7 kg.d−1, P < 0.001) while concentration of milk fat and protein were reverse (P < 0.05). Smaller portion of essential AADI in crude protein intake (CPI) in D-ERC resulted in lower efficiency of CPI utilization for milk protein synthesis in comparison to D-EFFS being 313 and 327 g.kg−1, respectively (P < 0.01). Concentration of AA in blood plasma was not affected by the type of diet except of His and Ile that were higher in D-EFFS (P < 0.01)

Influence of the load of nylon capsules on their passage through the digestive tract and specific gravity

The passage and specific gravity of nylon capsules were evaluated in five trials. In individual trials, different lactating cows were fed the same diet consisting of maize silage, alfalfa hay and concentrate. In each trial the different feeds (or no feed) were used to fill the capsules. The capsules were made of nylon cloth (42 $\mu$m pore size, 10 mm external diameter). The different weights of the load (L1–L5) were obtained using a combination of 2 and 3 mm stainless steel balls. The highest recovery of the capsules was obtained with the L3 and L4 loads (91.4 and 92.3%, resp.). After 14 hours of incubation in the rumen, the calculated values of functional specific gravity of the capsules ranged from 0.92 to 2.05 g$\cdot$cm$^{-3}$. It was concluded that L3 (one 2 mm and one 3 mm ball) was the suitable weight of the load

Analyse of relationships between freezing point and selected indicators of udder health state among cow, goat and sheep milk

Milk freezing point (MFP) is important quality indicator. Aim was to analyse the relationships of MFP to selected udder health milk indicators (MIs) by comparison between cows (reference), goats and sheep. Bulk milk samples came from 3 herds of Czech Fleckvieh (B, n 93) and 1 goat herd and sheep flock (White short-haired, W, n 60; Tsigai, C, n 60). Animal nutrition was performed under the typical country conditions. MIs which were investigated: DM, dry matter; SNF, solid non fat; L, lactose (all in %); SCC, somatic cell count (103 ml−1); EC, electrical conductivity (mS cm−1); MFP (°C); Na and K (in mg kg−1). W MFP was −0.5544 ± 0.0293, B −0.5221 ± 0.0043 and C −0.6048 ± 0.0691 °C. The B MFP was related to L (−0.36; P < 0.01), W was not related to L (−0.07; P > 0.05) and C was related to L (0.40; P < 0.01). These facts could be explainable by worse SCC geometric averages for used W (3,646 103 ml−1) and C (560 103 ml−1) milk as compared to B (159 103 ml−1). Only 0.5 and 10.5% of variations in MFP were explainable by variations in DM and SNF in B, 32.7 and 12.8% in W but already 49.4 and 45.0% in C. Higher C values were caused by high MFP variability, 11.8% (C) versus 0.8% (B). There is possible to derive the more reliable MFP qualitative limits for more efficient monitoring rules of milk quality problems in B, W and C

Effect of supplemental rumen-protected lysine, methionine or both added to diet of lactating dairy cows on milk fatty acids profile

The objective of this study was to determine the effect of supplemental lysine (Lys), methionine (Met) or both added to diet of dairy cows in the form of rumen-protected (RP) tablets on changes in milk fatty acids (FA) profile. The trial was carried out on four lactating Holstein cows in the form of Latin square design and was divided into 4 periods of 14 d (10-d preliminary period and a 4-d experimental period). The four treatments were as follows: C – control without amino acids (AA) supplementation, L – supplement of RP Lys, M – supplement of RP Met and ML – supplement of RP Met and Lys. Cows were fed on a diet based on maize silage, lucerne hay and supplemental mixture. Milk yield in ML (34.18 kg/d) was higher than in L or M (32.46 kg and 32.13 kg, respectively, P < 0.05) and tended to be higher than in C (33.33 kg/d, P > 0.05). Protein yield in ML (1054 g / d) was higher than that found in C, L or M (990, 998 or 968 g / d, respectively, P < 0.05). Milk fat content and yield in C and ML was higher in comparison to L and M (P < 0.05). Content of short-chain FA (C 4:0–C 12:0) was not affected by the treatment except of L that was lower than in C (P < 0.05). Content of medium-chain FA in M was lower compared to C, L or ML (P < 0.05). The content of long-chain FA in M was significantly higher than in other groups (P < 0.05). The total content of SFA in M was lower than in C or ML (P < 0.05) and tended to be lower than in L. Contents of UFA, MUFA and PUFA in M were higher than in C and ML (P < 0.05)