The aim of the thesis was to design an energy efficient system that uses a waste heat from the operation of distillery and helps to reach energetically active status (in conjunction with the newly designed photovoltaic panels, controlled ventilation with heat recovery and with proper design and material solution) to the newly created housing units. The need of heating is covered by using of waste heat and in the mode of economical (energy saving) operation of households, the photovoltaic panels on the surface produce more electricity than the households consume themselves.

This theses work is concerned with assessment of transfer line exchanger behind pusher furnace. First part is describing technical characteristic and parametres. The most important part of this theses is thermic calculation of the boiler. Last following part is concerned with suggestions of constructional modifications of heating surface for proper functioning of boiler. These modifications are demonstrated by scheme in the enclosure.

Master’s thesis deal with the design of waste to energy plant of municipal waste. The design of technology is to build the component parts of plant and basic calculation of individual apparatus. Overall technology concists of pretreatment of municipal waste, which is then stored in the bunker. Pretreatment municipal waste is fed into the counterflow rotary kiln. Flue Gates from the kilns are routed through multicyklony in the heat recovery steam generators (HRSG). The multicyklon separates the pollutants. The HRSG generates steam required properties from the feedwater from the heat kontent of gas. Superheated steam is driven to the condensing turbine with extract steam for distrikt rating and for power generation. The flue gas from the HRSG are passed through purification section, in which are separand pollutants the dry method purification. The left heat content of flue gas is used in heat exchanger with twist tube for preheating feed water for the HRSG. The flue gas are fed to the stack.

Objective of this Master’s thesis is to make search about generation and use biogas, with focus on cogeneration and to make search about possibilities of increasing the share of production of electricity by cogeneration from biogas. This final work has also the task to summarize possibilities of increasing the share with ORC cycle and to evaluate pros and cons of this use. Main part of this work is dealing with own design of increasing production of electricity with cogeneration from biogas in biogas station with ORC cycle and comparing this modification with steam engine.

This thesis deals with the problem of waste heat, namely, the exhaust gas which are not frequently used. Specifically, it is a design of thermoelectric generators set, power electronics for fan and heat exchanger proposal. The entire system uses the energy of the waste heat to increase the heating efficiency.

This master’s thesis deals with design of technological system for heating and process steam generation. The source of energy is a cogeneration unit. The thesis is divided into several parts. The first part is design of technological system and description. The second part is realized stoichiometric calculation and the thermal balance of steam boiler. The main part of thesis is design of the waste heat steam boiler. The thermal calculation, aerodynamic calculation, hydraulic calculation and strength calculation were made. The thesis also includes the drawing of designed waste heat steam boiler.

This thesis deals with the design of computational model of a biogas plant and its use in the concept of intelligent region with focusing on district heating and cooling network. The introduction contains review of technology used in the biogas plant. This review covers the description of modern biogas plants and determination of the energy and technology parameters for computational model of biogas plant. The next part of thesis describes analyze of the dynamics of the operation and the possibilities of using waste heat from biogas plant. The last and also the most important part is based on design of computational model of a biogas plant and design of connection of a biogas plant to the district heating and cooling network.

This dissertation thesis deals with the development of technology which could tackle two major issues related to biogas plants. These issues concern the insufficient use of waste heat from biogas combustion and its subsequent processing. It also concerns the use of the fermentation residues which are formed in large quantities and whose use is restricted by law. Based on a literary search of separation methods, a vacuum evaporator was selected as the most suitable technology. Its advantages include its simple construction, operational reliability and robustness, low costs of thickening medium pre-treatment, potential for a quick commercial application and, especially, the chance to use a low-potential waste heat. A primary purpose of this technological unit is the reduction in the volume of fermentation residues. Other benefits include the efficient use of waste heat from a biogas plant, which would otherwise be wasted. Evaporators with a low consumption of electrical energy (which is a main product of a biogas plant) seem to be the best option for applications in the biogas plants. Three of these technologies were subjected to a more thorough analysis, which included the development of computational models and their quantification for conditions in a sample biogas plant. A one-stage evaporator with a forced circulation (680 – 712 kWhth/m3, 25.9 – 30.5 kWhel/m3) was evaluated as the least suitable option in terms of energy demands. The energy intensity of a three-stage evaporator with a falling film (241 – 319 kWhth/m3, 12.0 – 23.6 kWhel/m3) and a nine-stage flash evaporator (236 – 268 kWhth/m3, 13.6 – 18.4 kWhel/m3) is significantly lower. A multi-stage flash evaporator (MSF) was then chosen for development and will form the central focus of this thesis. The reasons for the choice are as follows: the low requirements on the heat transfer surface, good operational experience in the field of desalination, its simple construction, modularity and evaporation outside the heat transfer surface. A thorough technical-economic evaluation was also performed on the integration of the evaporator into the biogas plant. The main part of the work included the experimental development of a MSF evaporator prototype. The main objective of this development was to achieve a stable flow rate of the thickening liquid digestate fraction and the continuous formation of the distillate. This was not an easy objective to achieve, especially due to the properties of the liquid digestate, which has a non-newtonian characteristic and increased density and viscosity compared to water. The tendency of the liquid digestate to form foam was also the subject of analysis. The development of the evaporator and first successful operational test are described in the thesis in detail. This required the use of an anti-foaming product. A fully-developed prototype of the MSF evaporator allowed us to achieve continuous operation with a distillate production, reaching from 5 to 10 kg/h at a liquid digestate flow rate of 0.4–0.5 m3/h. The main drawback of this technology is the pollution of the distillate with ammonia nitrogen, and it is for this reason that the basic procedures of its subsequent elimination was selected for further analysis.

A heavy duty vehicle looses approximately 30-40 % of the energy in the fuel as waste heat through the exhaust system. Recovering this waste heat would make the vehicle meet the legislative and market demands of emissions and fuel consumption easier. This recovery is possible by transforming the waste heat to electric power using a thermoelectric generator. However, the thermoelectric generator electric characteristics makes direct usage of it unprotable, thus an electric power conditioner is necessary. First a study of dierent DC-DC converters is presented, based on that the most suitable converter for thermoelectric application is determined. In order to maximize the harvested power, maximum power point tracking algorithms have been studied and analyzed. After the investigation, the single ended primary inductor converter was simulated and implemented with a perturb and observe algorithm, and the incremental conductance algorithm. The converter was tested with a 20 W thermoelectric generator, and evaluated.The results show that the incremental conductance is more robust and stable compared to the perturb and observe algorithm. Further on, the incremental conductance also has a higher average eciency during real implementation.

Att minska energianvändningen är något det pratats mer och mer om de senaste åren. Det finns olika sätt att minska energianvändningen på och ett av dessa är att återvinna värmeenergi. Det kan gälla både spillvärme och nyttig värme. Detta går att tillämpa i industrin, transportsektorn, hushåll och till vardags. Gemensamt för dessa processer är att det används stora mängder energi vilket till stor grad består av förluster till omgivningen eller att processerna inte optimeras. På senare tid har det forskats kring teknologi som kan ta vara på denna värmeenergi och på så vis minska förlusterna. En teknologi för detta är termoelektriska generatorer (TEG) som bygger på Seebeckeffekten för att generera elektricitet från temperaturskillnader. När ett TEG-element utsätts för värme på en sida och kyla på den andra sidan så genereras en elektrisk spänning. En elektrisk ström och effekt kan tas ur kretsen om elementet kopplas till en elektrisk last. Materialet i elementet består av halvledarmaterial med låg värmeledningsförmåga och en hög elektrisk ledningsförmåga. Teknologin har funnits länge men aldrig tillämpats i någon större grad. Nu på senare år har intresset ökat och kommersiella produkter med TEG-element har tagits fram. I detta arbete har en sådan produkt testats för att se hur lämpligt det skulle vara att använda dessa vid hushåll som inte är anslutna till elnätet och har en vedkamin för uppvärmning. TEG-enheten testas på en värmeplatta där ställbara temperaturer är möjliga för att testa prestandan vid temperaturerna 150° C, 200° C och 230° C. En krets sätts ihop för att kunna mäta av värden på spänning och ström vid olika laster som sätts med resistorer. Mätningarna görs med en ökning på 0,1 A vid varje mätning. Resultatet från dessa tester visar att maximal effekt på 14 W uppnås hos produkten vid 230° C. När modifiering av produkten görs för att öka temperaturskillnaden uppnås 17,8 W vilket tyder på att effekten ökar när delta T ökar. Den spänning som uppnås vid öppen krets var som högst 31 V och vid maximal effekt var den 17,8 V. Strömmen var då 1 A. De resultat som testerna gav levde inte upp till de 25 W som produkten sägs kunna ge. Produkten saknar även viktiga komponenter så som spänningsreglerare.Det går av både teori och tester avgöra att det är ett lämpligt sätt att använda sig av TEG-enheter för att generera små mängder elektricitet vid hushåll utan koppling till elnätet. / In recent years the topic of reducing the energy usage has been on the agenda. There are several ways of reducing the energy usage and one of these is to recycle heat energy. It could be both waste heat and useful heat. This can be implied to the industry, transport sector, households and on daily activities. The common factor between these is that large quantities of energy is used and to a large extent consists of losses to the surrounding or from processes that are not optimized. In recent time there has been done research around technology that can recycle and use this heat energy and in return reduce the energy usage. One technology to do this is thermoelectric generators (TEG) that are implementing the Seebeck effect to generate electricity from temperature differences. When a TEG-element have one side that is exposed to a heat source and one side being cooled down an electric voltage is being generated. An electric current and power can then be used from the circuit if the element is connected to an electric load. The material in the element exists of semiconductive materials with low heat conductivity and high electric conductivity. The technology has existed for a long time but has never been implemented to a larger extent. It is only in recent years that the interest has grown and some commercial products with TEG-elements has been developed. In this thesis one of these products has been tested to see how viable it would be to use these within a household that is not connected to the electrical grid and where the house is heated with a wood-burning stove. The TEG-product is tested on a heat plate where it is possible to set a desired temperature. The temperatures of 150° C, 200° C and 230° C are chosen for testing the performance of the product. A circuit is put together to be able to read the values of the voltage and current at different loads that are set with resistors. The measurements are done with an increase of 0,1 A for every measurement. The result from these tests shows that the maximum power of 14 W is achieved at 230° C on the hot side. But when modification of the product is made to increase the temperature difference a value of 17,8 W is attained. This indicate that the power is increasing when the temperature difference is increasing. The attained voltage at open circuit was as highest 31 V and at maximum power it was 17,8 V. The current was then 1 A. The results that the testing gave did not match the value of 25 W that the datasheet says the product can deliver. Also, the product is missing important components such as voltage regulator.It is possible from both the theory and the testing to see that it is suitable to use a TEG-product to generate small amount of electricity to households that are not connected to the electrical grid.