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.

Energy efficiency in the building sector is crucial for many countries in succeeding with the completion of goals regarding energy efficiency. This study has investigated if there are any possible and reasonable solutions for Attefallshus in Sweden to meet the demands of the National Board of Housing regarding energy performance in houses. By building a model and calculating the annual energy usage for a specific Attefallshus, through simulations with the software IDA ICE and general input, an energy audit has been obtained. By comparing the specific energy usage for the studied case with the requirement the conclusion that it is possible for this small building to achieve a low enough energy usage to meet the demand. Solar cells are the key to accomplish the target of a low specific energy usage and by combining this with an effective system for heating it possible to get under the limit. The usage of domestic hot water is a very large part of the building specific energy usage and alone almost reaches the set bounds which is why it is of great importance to carefully design systems and to regain heat with effective ventilation. A large part of the energy usage in Attefallshus is related to the user why awareness and careful usage of energy is a significant factor in reaching a low specific energy usage.

La part de consommation d'énergie primaire d'eau chaude sanitaire (ECS) dans des bâtiments à basse consommation (BBC) devient proportionnellement importante quand comparée aux autres postes. Actuellement, l'intégration des systèmes dans les nouveaux bâtiments ne présente pas de difficulté. En revanche, le marché de la rénovation est mal exploité, et une des contraintes importante est le placement du ballon de stockage. Dans le cas où le ballon doit être placé en dehors du bâtiment, les solutions existantes ne sont pas satisfaisantes, ni d'un point de vue thermique (fortes pertes), ni d'un point de vue esthétique (réservoir visible à l'extérieur). Dans le cadre de cette thèse, nous avons étudié une solution innovante visant à intégrer le stockage au capteur, afin de permettre une intégration complète du système au niveau de la toiture. Le critère énergétique nous a conduit à proposer un volume de stockage totalement isolé où l'apport de chaleur se produit en partie basse. Nous réalisons dans le cadre de la thèse une étude expérimentale d'une cavité à haut rapport de forme, qui nécessite la réalisation d'un système de stratification. Ce système, une plaque, a été étudié numériquement pour optimiser le placement du fluide en partie haute. Enfin un modèle global a été conçu pour les simulations de performance annuelle. Ce modèle se montre satisfaisant, et montre que la performance du système est légèrement inférieure aux systèmes classiques (thermosiphon). Les pertes thermiques ont été le facteur le plus pénalisant. Le dimensionnement d'un prototype a été réalisé, et ce dernier sera testé au cours de l'année 2012. / The primary energy consumption of domestic hot water (DHW) in low energy house becomes proportionately large when compared to other energy consumptions. In new buildings, the integration of DHW systems do not present any difficulty. However, the thermal renovation market is poorly operated, with the storage's placement as the main constraint. When the storage must be placed outside the building, nowadays the solutions are not satisfactory, or by a thermal point of view (high losses), or an aesthetic point of view (tank visible from outside). In this thesis we studied an innovative solution of an integrated storage collector, allowing full integration at the roof and completly insulated. The storage is heated at the bottom. A cavity with high aspect ratio has been studied experimentaly and the cavity requires a stratification system. This system, a plate, was numerically studied to optimize the placement of the fluid at the top. Finally a global model was developed for annual performance simulations. This model proves satisfactory and shows that system performance is slightly lower than conventional systems (thermo- siphon). Heat loss was most detrimental factor. The design of a prototype was produced, and it will be tested during the year 2012.

This thesis's main objective is to conduct a comparison study between measured values and simulated results of a demonstrator, of the intelligent home energy management (iHEM) project. The comparison helps to validate the simulation. TRNSYS software is used for the design. In this study, only the thermal energy side of the project is considered. In which system-level (both domestic hot water (DHW), space heating (SH)) and component level (solar collector, gas boiler) are considered as the parameters to compare. An attempt is made to optimize both system-level and component-level simulation outputs with measured values by adopting measured boundary conditions as simulation inputs.During the comparison, the DHW loop simulation design is modified. The measured data were given as input files for simulation, replacing the estimated values used before. This is done to optimize the simulation output with measured data. In the space heating loop (SH), the simulated building model’s parameters were changed to optimize the SH demand. After the system-level validation and optimization, the component level comparison is carried out. For this, the simulation output of solar thermal collectors and gas boiler are compared with measured values. The solar collector loop in the simulation is modified to optimize the simulated results. The seasonal and yearly efficiencies of the collector have been calculated. Solar supply fraction and gas boiler supply fraction is also determined. For the comparison, graphs are plotted for three different weeks, representing the spring, summer, and winter months of 2018.The final optimized simulation output of DHW demand is 7% less than the measured value. Even after optimizing the Space heating loop (SH), the simulated building demand is 17% more heat than the demonstrator building. The simulation's solar collector output is optimized close to the measured values. The simulated gas boiler produces 19% more than the demonstrator system to meet excess SH demand in the simulation (including losses). The overall yearly collector efficiency calculated for measured and simulated values are 58% and 50%, respectively. The estimated solar collector supply fraction and gas boiler supply fraction is 26%, 76% for measured, and 23%, 81% for simulation, respectively.

The work generally deals with the possibilities of preparing hot water in household and analyzes saving posibilities. At the beginning of work the history of hot water preparation is briefly indicated. Chapter 3 deals with different ways of heating. Described in more detail electric storage heating is in chapter 4, where can be found the effect of heating to the power network, especially to the daily load diagram. The following are the information of the tariff policy, as a tool for motivation of consumers, for using the storage heating. In the next part, beginning with the fifth chapter, is written about the possibility of energy saving by means of intelligently controlled boiler. That eliminates the disadvantage of storage heating, which are the tank thermal losses. Heating is based on a certain regularity in the behaviour of the user and manages the preparation of water according to expected consumption. The sixth chapter then contains design of own algorithm for economical control of heating and also energetic and economic assessment of potential savings.

This thesis deals with the reconstruction of sanitary installations in the multi-purpose sports facility STARS in Třinec. It is a large complex with an administration building. The theoretical part is focused on heating and distribution of hot water. It considers multiple solutions to the problem. The practical part then deals in depth with one of the discussed options in a selected few buildings.

Diploma thesis deals with change of heating source for a block of flats with aim to reduce heating costs. Thesis contains calculations of energy requirements of house, including requirements for heating and domestic hot water preparation. Several ways of heating by a heat pump were designed based on the calculated values. Each variant of the designed heating system is compared with current operational costs. Possible cost economies and maximum value of investment costs of the heating system were assessed

The final thesis deals with the heating of the hospital building and preparation of the domestic hot water by cogeneration unit. The building will be largely heated by plate radiators. As a heat source is used a cogeneration unit with combustion engine. The project deals with the design dimensioning and connection of these parts.

In view of the fact that most of the synthetic refrigerants, in case of leakage or release, are harmful to the environment by contributing in global warming or depleting stratospheric ozone layer, many research works have been done recently to find alternative refrigerants posing no or negligible threat to the environment. Among alternative refrigerants, ammonia, a natural refrigerant with zero Global Warming Potential (GWP) and Ozone Depletion Potential (ODP), can be a sensible choice.Although ammonia has been used for many years in large industrial systems, its application in small units is rare. In this project a small heat pump with about 7 kW heating capacity at -5 °C and +40 °C evaporation and condensation temperatures is designed and built to work with ammonia as refrigerant. The heat pump is expected to produce enough heat to keep a single-family house warm in Sweden and to provide tap hot water for the house. After successful completion of this project, it is planned to install the heat pump in a house to test it throughout a heating season to study its performance in real working conditions.Since ammonia is flammable and toxic in high concentrations, the refrigerant charge is tried to be kept low in the heat pump to reduce the risk of fire or poisoning in case of unwanted release of refrigerant to the surroundings. The compact design of the heat pump helps reducing the refrigerant charge. Besides, considering the limited space normally reserved for installation of a heat pump in a house, the compact design of the heat pump is necessary.

This thesis's main objective is to conduct a comparison study between measured values and simulated results of a demonstrator, of the intelligent home energy management (iHEM) project. The comparison helps to validate the simulation. TRNSYS software is used for the design. In this study, only the thermal energy side of the project is considered. In which system-level (both domestic hot water (DHW), space heating (SH)) and component level (solar collector, gas boiler) are considered as the parameters to compare. An attempt is made to optimize both system-level and component-level simulation outputs with measured values by adopting measured boundary conditions as simulation inputs.During the comparison, the DHW loop simulation design is modified. The measured data were given as input files for simulation, replacing the estimated values used before. This is done to optimize the simulation output with measured data. In the space heating loop (SH), the simulated building model’s parameters were changed to optimize the SH demand. After the system-level validation and optimization, the component level comparison is carried out. For this, the simulation output of solar thermal collectors and gas boiler are compared with measured values. The solar collector loop in the simulation is modified to optimize the simulated results. The seasonal and yearly efficiencies of the collector have been calculated. Solar supply fraction and gas boiler supply fraction is also determined. For the comparison, graphs are plotted for three different weeks, representing the spring, summer, and winter months of 2018.The final optimized simulation output of DHW demand is 7% less than the measured value. Even after optimizing the Space heating loop (SH), the simulated building demand is 17% more heat than the demonstrator building. The simulation's solar collector output is optimized close to the measured values. The simulated gas boiler produces 19% more than the demonstrator system to meet excess SH demand in the simulation (including losses). The overall yearly collector efficiency calculated for measured and simulated values are 58% and 50%, respectively. The estimated solar collector supply fraction and gas bo