Master thesis deals with heat recovery in ventilation systems. Thes is an experimental measurement of the plate heat exchanger for a period of one year. Thes is Compaq es the efficiency of the heat exchanger manufacturer with achal field measurements. The first part describes the theoretical heat recovery systems, thein advantages and disadvantages, the basic formula for calculating efficiency. In the second part I come to the experimental measurements of the plate heat exchanger. There sult of this thesis is to Compaq the efficacy, showing behavior exchanger seasons and energy evaluation.

The diploma thesis is consisting of theoretic part, which deal with used ventilating systems, ways of waste heat recovery and describe basic types of air-conditioning systems. Following part attend to design of ventilating system and multi-split air-conditioning system for flat. Part of design of ventilation system is calculation of noise levels in rooms. Air-conditioner design is based on calculation of thermal stress. Annual demand of cold and heat demand are calculated using TRANSYS software. Design documentation is part of the diploma thesis.

This thesis deals with thermal calculation and design of proportions and layout of calorific components of a heat recovery steam generator according to given output parameters of steam and input parameters of flue gas. Furthermore, the proportions of boiler drums and irrigation and transfer pipes are designed and draught losses are calculated.

This master‘s thesis describes thermal calculation and design of proportions of calorific components of a heat recovery steam generator (HRSG) for given input parameters of flue gas and output parameters of steam. Part of the thesis is design proportions of boiler drums, irrigation and transfer pipes. On the end of the thesis is counting draught losses and design drawning of steam generator.

This master´s thesis deals with two pressure heat recovery steam generator behind gas turbine. From the entered parameters steam and gas were designed heating surfaces, specifically their size and configuration. The overall design is then proposed in the drawing.

Diploma thesis presents various methods of energetic utilization of wastewater. It shows that wastewater is source of heat energy that has not been used yet. The thesis focuses mainly on heat recovery from wastewater from sewer bypass by modular heat exchangers. Design of heating of polyfunctional building from bypass from main sewer in Brno is developed. The main finding is that wastewater as low potential source of energy can together with heat pump be not only used for heating and heating of domestic hot water but also for cooling of polyfunctional object. Part of work is also technical-economical assessment by the NPV method.

This project was performed to evaluate if waste heat from hotel kitchens is enough to heat outdoor swimming pools in southern Europe or if it can be used as a compliment to another heat source. Another aim was to analyze the simulations and calculations of the pools and the heat recovery system. Then estimate how much annual costs would be reduced when using the exhaust air in the heat recovery system, in comparison with the original heating system. If the project showed positive results the purpose was to select a waste heat recovery system that can integrate with Ozonetech’s ozone generator, keep a high temperature in the pool and reduce emissions of greenhouse gas by using waste heat. Ozonetech would also conduct a pilot study in Stockholm and eventually develop their own product. A simulation model of three different outdoor pool sizes were conducted. The models were constructed and meshed in COMSOL Multiphysics. Average weather conditions for Malaga, Spain, were implemented in the model. The models were simulated by integrating each physical phenomenon in COMSOL, by using the Multiphysics interface. This created convection, emitted radiation and evaporation as thermal heat losses from the pool models. The pools were simulated to determine heating demand, heating period and required inlet temperature to make up for thermal heat losses. A mathematical model of the thermal heat losses and gains were conducted to easily receive a result for the heat demand each month of the year. A mathematical model of the possible heat recovery from hotel kitchens were performed to determine heat recovery for various kitchen sizes. By knowing the heat demand and possible heat recovery from different kitchens, a heat exchanger was selected. The heat exchanger was selected based on literature review, requirements and discussions with manufacturers. A life cycle cost analysis and calculated payback time compared original heating systems with new heat recovery system. A sensitivity analysis using Gauss error propagation concluded the project. The simulations showed that all investigated outdoor pools require additional heat during the night, due to extensive heating periods. Since the kitchen is only active during the day, the pool requires an additional heat source during the night. This conclude that the new heat exchanger only can replace the original heating system during the day. The mathematical model of the heat transfer from the kitchen determined that the maximum heat capacity approximately is 350 kW ± 10.5 kW. The waste heat can only be used to heat small and medium sized pools, since the heat loss is too great for a large pool. Selected air to water heat exchanger that meets the requirements is an air cooler with finned tubes from Alfa Laval. The fins and the coil should be treated to form an e-coat. After calculating the life cycle cost it was determined not profitable to replace a heat pump for a small pool, since the life cycle cost was greater for the new heating system. However, it is profitable to replace an electric heater with the new heat exchanger together with three of the smallest ozone generators during the day, for a small pool. Costs will be reduced by 44 600 – 202 000 kr ± 5%. Payback time will be 2.4 – 3.2 years ± 9%. It is also profitable to replace a water to water heat exchanger heated with either electricity or oil, during the day, with the new heat exchanger combined with either of the ozone generators for a small pool. Costs will be reduced by 310 000 – 698 000 kr ± 5%. Payback time will be 1.8 – 2.5 years ± 9%. It is profitable to replace all original heating systems during the day with the new heat exchanger combined with either of the ozone generators for medium sized pools. Costs will be reduced by 689 000 – 12 600 000 kr ± 5%. Payback time will be 2.2 – 22 months ± 7%.

The importance of energy efficiency in the operation of the built environment is becoming increasingly important. Energy use in the building sector has exceeded both transportation and industry, while within buildings heating, ventilation, and air conditioning has the greatest share. In light of the recent pandemic forcing governments to issue quarantines and stay-at-home orders people are spending even more time indoors, this further emphasizes the importance of proper ventilation and the impacts on energy use. The purpose of this research was to perform a case study of a low environmental impact demonstration house to compare the energy performance of various ventilation strategies. The ventilation strategies varied by overall airflow rate, control strategy, and the presence of heat recovery. Performance was evaluated by establishing a model in IDA ICE, an equation-based modeling tool for the simulation of indoor thermal climate and energy use. The results showed energy savings due to demand-control with a reduction of 12.5%. Results also showed similar savings with a heat recovery system, indicating that any savings in heat loss due to heat recovery is at the expense of increased auxiliary energy. In this particular case, the benefit of upgrading to a heat recovery system from simple demand control set up is not readily apparent. Results also demonstrated trends and possible complications useful to future research plans that aim to measure real world ventilation performance, including how differences in the number and location of sensors impact the efficacy of the demand-controlled systems. A secondary aim was to observe how a newly constructed, low environmental impact home built in Sweden performs according the residential LEED energy budget. The results demonstrated that constructing a house using low impact materials with low embodied energy does not have to negatively impact energy performance, scoring extremely well in the Energy and Atmosphere category of a widely used sustainable building rating system.

As buildings have become more energy efficient, the energy demand for preparation of domestic hot water stands out as an increasing part of the operational cost and carbon footprint of a building. Most of the heat in the water is used for a short time and then discharged to the main sewer line. Clarion Hotel Stockholm is an example of such a building, with many showers, bathtubs and a spa. The hotel business is growing around the world and its customers demand comfortable stays. A parallel trend is a more environmentally aware tourism and business travel. Hotels show a great potential for energy savings, while still offering comfortable accommodation. In this master's thesis a case study evaluates the possibilities for heat recovery from the wastewater of Clarion Hotel Stockholm. Three types of heat exchangers were modelled in the system dynamic modelling environment STELLA: a horizontal, a vertical and a shower heat exchanger. Recovered heat was used for pre-heating of the incoming water for domestic hot water preparation. The flows of heat through the hotel's tap water and wastewater systems were schematically modelled using system dynamic modelling, which provides a foundation for the development of mathematical models and further research into the area. The first results point to possible reductions of the heating demand for domestic hot water preparation at Clarion Hotel Stockholm.

Die vorliegende Arbeit ist die erste empirische Studie zum Betriebsverhalten von unbelüfteten Festbettreaktoren mit Wärmeentzug, sog. Biomeilern. Es werden vier Biomeiler systematisch und mehrschichtig hinsichtlich der biochemischen Abbauprozesse untersucht. Zusätzlich dazu werden die Daten von 130 Temperatursensoren über einen Zeitraum von 140 Versuchstagen für eine energetische Bewertung herangezogen. Die Bewertung der biochemischen Abbauprozesse erfolgt durch Analyse des Substratgemischs, der Gaskonzentration im Haufwerk und der Temperaturverteilung. Im zylinderförimgen Reaktorraum wird eine rotationssymetische Verteilung der Zustandsgrößen nachgewiesen, um deren Rotationsachse hohe Methankonzentartion, abhängig vom Gesamtvolumen, nachweisbar sind. Die energetische Bewertung ergibt eine maximale Wärmeleistung von 5 kW über einen Zeitraum von 60 Tagen für 12h Wärmeentzug pro Tag. Diese Werte sind mit den publizierten Höchstwerten für die Wärmeleistung vergleichbar. Zur Erfassung der maximal möglichen Wärmeleistung war das gegebene Versuchsobjekt mangelhaft. Zur Verbesserung sowohl der Wärmeleistungsbereitstellung als auch der Prozessführung wird eine Belüftung vorgeschlagen und erläutert. Ein möglicher Einsatz im Bereich der regenerativen Energieversorgung im Niedertemperaturbereich (bsp. Flächenheizungen) oder zur Deckung der Heizgrundlast sind denkbar.:1 Einleitung 2 Problemstellung und Zielsetzung 3 Grundlagen der Kompostierung 3.1 Definition 3.2 Mikroorganismen der Kompostierung 3.3 Substrat 3.3.1 Nährstoffe 3.3.2 Wassergehalt 3.3.3 Porengröße und Partikelgröße 3.4 Temperatur, Kohlenstoffdioxid und Sauerstoff 3.4.1 Zusammenhänge 3.4.2 Hygienisierung 3.4.3 Temperaturführung 3.5 Belüftungsverfahren statischer Reaktoren 3.5.1 Bedeutung 3.5.2 Aktive Belüftungsverfahren 3.5.3 Passive Belüftungsverfahren 3.5.4 Dombelüftungsverfahren 4 Stand der Wissenschaft 4.1 Theoretische Modellierung 4.1.1 Allgemeines 4.1.2 Thermodynamische Modellierung 4.1.2.1 Wärmebilanz 4.1.2.2 Speicherwärme und spezifische Wärmekapazität 4.1.2.3 Wärmeübertragung 4.1.2.4 Wärmeverlust 4.1.3 Modellierung der Selbsterhitzung und Reaktionswärme 4.1.3.1 Begriffsbestimmung 4.1.3.2 Deterministisch geprägte Modelle 4.1.3.3 Stöchiometrische Modelle mit Prozessgasen 4.1.3.4 Abschätzung durch den Heizwert des Substrat 4.1.3.5 Abschätzung durch die Heizwerte der Nährstoffe 4.1.4 Modellierung des Wasserhaushalts 4.2 Technologien zum Wärmeentzug aus der Kompostierung 4.2.1 Möglichkeiten des Wärmeentzugs 4.2.2 Steuerung der Prozesse 4.2.2.1 Bedeutung 4.2.2.2 Belüftung 4.2.2.3 C:N-Verhältnis 4.2.2.4 Temperaturführung 4.2.3 Bestehende Verfahren zum Wärmeentzug aus der Kompostierung 4.2.3.1 Kontinuierliche Verfahren 4.2.3.2 Kurzzeit-Batch 4.2.3.3 Langzeit-Batch 4.3 Datengrundlage zur Wärmeleistung 4.3.1 Ermittlung der Wärmeleistung 4.3.2 Experimente und Fehleranalyse 4.3.3 Datengrundlage 4.4 Fazit 5 Methoden zur Vermessung der Biomeiler 5.1 Versuch 5.1.1 Versuchsfeld und Umgebungsbedingungen 5.1.2 Aufbau und Betriebsweise der Biomeiler 5.1.2.1 Aufbau und Sensorik 5.1.2.2 Substratvorbereitung 5.1.2.3 Steuerung des Wärmeentzugs 5.1.3 Versuchszeitraum 5.2 Messungen 5.2.1 Charakterisierung des Substrats 5.2.1.1 Probenahme und Messpunkte 5.2.1.2 Schüttdichtemessung 5.2.1.3 Laboruntersuchungen 5.2.2 Temperaturmessungen 5.2.2.1 Automatisierte Temperaturmessungen 5.2.2.2 Manuelle Temperaturmessungen 5.2.2.3 Messung der Oberflächentemperatur 5.2.3 Volumenstrommessung im Heizkreislauf 5.2.4 Messung der Gaszusammensetzung im Festbettreaktor 5.2.5 Messung der Wetterdaten 5.3 Messfehlerbetrachtung 5.3.1 Nicht-quantifizierbare Fehlerquellen 5.3.2 Quantifizierbare Fehlerquellen 5.3.3 Auswertung der Fehler der manuellen Messungen 5.4 Auswertungsverfahren 5.4.1 Auswahl der Biomeiler 5.4.2 Darstellung des vertikalen Profils 5.4.3 Berechnung der Wärmeleistung 6 Auswertung 53 6.1 Auswertung der Wetterdaten 6.2 Charakterisierung des Substrats 6.2.1 Schüttdichte 6.2.2 Wassergehalt, Wärmekapazität und -leitfähigkeit 6.2.3 C:N-Verhältnis und Heizwert 6.2.4 Korngröße und oTS 6.2.5 Volumenschwund durch Setzung 6.3 Untersuchung des horizontalen Profils 6.4 Untersuchung des vertikalen Profils 6.4.1 Annahmen und Begriffsbestimmung 6.4.2 Profil der Schüttdichte und des Abbaugrads 6.4.2.1 Schüttdichte 6.4.2.2 Abbaugrad 6.4.3 Profil der Gaszusammensetzung 6.4.3.1 Gaskonzentrationen im Festbettreaktor 6.4.3.2 Optischer Nachweis der Mikroorganismen 6.4.4 Profil der Temperatur 6.4.4.1 Temperaturfeld im Festbettreaktor 6.4.4.2 Oberflächentemperatur 6.5 Untersuchung der Reaktionswärme und des Wärmeentzugs 6.5.1 Abhängigkeit von dem Biomeilervolumen 6.5.2 Abhängigkeit von der Steuerung des Wärmeentzugs 6.5.3 Auswertung der Wärmeleistung 6.5.4 Identifikation von Einflussfaktoren 6.5.4.1 Abhängigkeiten der Parameter 6.5.4.2 Einfluss der Umgebungsbedingungen 6.6 Ansatz zur Erweiterung eines Modells 6.6.1 Auswahl des Modells 6.6.2 Wärmebilanz 6.6.3 Räumliche Verteilung der Zustandsgrößen 6.6.4 Wärmeübertragung zum Wärmeübertrager 7 Bewertung und Diskussion 8 Zusammenfassung 9 Ausblick Literatur Anhang