Ground-source heat pump systems with vertical ground heat exchangers (GHE) are gaining popularity worldwide for their higher coefficients of performance and lower CO2 emissions. However, the higher initial cost of installing the borehole GHEs is a main obstacle to spread the systems. To reduce the required total GHE length and efficiently operate the systems, various systems such as hybrid ones (e.g. solar heat injection) have recently been introduced. Accurate prediction of heat transfer in and around boreholes of such systems is crucial to avoid costly overdesigns or catastrophic failures of undersized systems as it is for typical GCHP systems. However, unlike the traditional sizing methods, it is increasingly required to take into account detailed borehole configuration and transient effects (e.g. short circuit effects between U-tubes). Many of the existing GHE models have been reviewed. Some of these models have serious limitations when it comes to transient heat transfer, particularly in the borehole itself. Accordingly, the objective of this thesis is to develop a model that is capable to accurately predict thermal behaviors of the GHEs. A precise response to input variations even in a short time-step is also expected in the model. The model also has to account for a correct temperature and flux distribution between the U-tubes and inside the borehole that seems to be important in the solar heat injection case. Considering these effects in 3D with a detailed mesh used for describing the borehole configurations is normally time-consuming. This thesis attempts to alleviate the calculation time using state model reduction techniques that use fewer modes for a fast calculation but predict similar results. Domain decomposition is also envisaged to sub-structure the domain and vary the time-step sizes. Since the decomposed domains should be coupled one another spatially as well as temporally, new coupling methods are proposed and validated particularly in the FEM. For the simulation purpose, a hybrid model (HM) is developed that combines a numerical solution, the same one as the 3D-RM but only for the borehole, and well-known analytical ones for a fast calculation. An experimental facility used for validation of the model has been built and is described. A comparison with the experimental results shows that the relatively fast transients occurring in the borehole are well predicted not only for the outlet fluid temperature but also for the grout temperatures at different depths even in very short time-steps. Even though the current version of 3D-RM is experimentally validated, it is still worth optimizing the model in terms of the computational time. Further simulations with the 3D-RM are expected to be carried out to estimate the performance of new hybrid systems and propose its appropriate sizing with correspondent thermal impacts on the ground. Finally, the development of the model 3D-RM can be an initiation to accurately model various types of GHE within an acceptable calculation time.

Thesis (M.S.)--University of Wisconsin--Madison, 1996. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 143-162).

The building stock in the European Union accounts for over 40% of final energy use, where the usage of non-residential buildings may be up to 40% higher than the residential sector. Improving building energy efficiency across all categories of buildings is one key goal of the European energy policies, made prominent by the Climate and Energy package, Energy Performance of Building Directive (EPBD) and Energy Efficiency Directive (EED). In this study, a simulation model of an office-building complex utilizing district heating was created using transient simulation software TRNSYS. The model was validated using consumption data provided by the facility owner, after which an investigation of the energy saving potential along with the economic viability of adapting a new heat- and power supply system was conducted. The system designs were comprised of a geothermal energy system in combination with a PV-system and electricity storage. It was concluded that the systems were sufficient in maintaining an adequate indoor climate. Furthermore, the investments were ascertained as profitable and resulted in a decreased building specific energy demand.

Since the building construction area is accounted for high share of energy usage (36 %) in Europe, there is high demand to pay attention to this area accurately. Sweden which is one of the pioneer countries in terms of building energy efficiency plans to reduce this value to 50 % by 2050. To reduce this value there is a need to define a mandatory guideline for builders by the government. So national board of housing, building and planning (Boverket) were given responsibility to define these regulations for builders and house owners. Parallel with that Swedish green building council developed a certification considering the buildin g’s energy demand, indoor air climate and environmental impact of building called Miljöbyggnad. While all the existing and new buildings following Boverket’s regulations meet this certification’s lowest limitations, some ambitious builders tend to fulfil its highest level of limitations called Gold level. This study aimed to design a house in the area of Smedjebacken to meet Miljö byggnad’s gold house’s energy category requirements. To meet the mentioned requirements several parametric studies regarding insulation thickness, windows assembly, heating and ventilation system are done via simulation software called TRNSYS. The result of testing several models show that although windows assembly does not affect this building ’s energy demand very much, other parameters such as insulation ’s thickness and type of heating system have a key role. In addition, a parametric study regarding the impact of thermal mass on the building energy demand is performed. The result shows that the effect of removed massive wood is compensated by replaced additional mineral wool insulation. In conclusion it is concluded that a single family house located in a cold climate like Smedjebacken using district heating cannot meet Miljöbyggnad’s gold level criteria without help of heat recovery ventilation. Furthermore, building with ground source heat pump as its heating system can meet Miljöbyggnad’s principals easier than those having district heating. In this case building with 200 mm insulation thickness even with exhaust air ventilation meets certification principals easily.

A constituição de sistemas híbridos como alternativa ao fornecimento de energia da concessionária, gerando energia própria e operando de forma isolada ou interconectada ao sistema de distribuição, tem originado estudos e implementações em nível industrial, comercial e mais recentemente residencial. A principal discussão que surge são as análises das vantagens técnicas e econômicas pela opção desse tipo de instalação. Neste trabalho, é apresentado um estudo complementar às pesquisas realizadas, onde é projetado um sistema híbrido contendo aerogeradores, painéis fotovoltaicos, processo de eletrólise, célula a combustível, microturbina a gás e geradores diesel. Esse sistema é simulado e comparado técnica e economicamente a um sistema que contém apenas geradores diesel. O sistema híbrido proposto possui uma microrrede conectada a um típico sistema de distribuição mas com um limite de demanda contratada que impede a satisfação de todas as necessidades energéticas da instalação apenas com a energia da concessionária. Procura-se avaliar os impactos técnicos e econômicos do atendimento da demanda por eletricidade através deste sistema híbrido além de executar-se a otimização, via PSO, do dimensionamento deste sistema, que utiliza uma ordem de despacho para gerenciar as mini unidades geradoras de energia. Foi utilizado o software TRNSYS devido a sua característica de permitir estimar a potência e energia produzidas no intervalo de um ano com detalhamento horário de cada recurso, considerando estimativas reais e localizadas para a disponibilidade dos recursos eólicos e fotovoltaicos. / The designing of hybrid systems as an alternative to power supply from power utility, generating their own energy in operating islanded or grid-tie to the power utility, has resulted in studies and implementations in industrial, commercial and residential level recently. The main discussion that arises is the analysis of the technical and economical advantages for this type of solution. This work presents a complementary study to the researches conducted nowadays, which is designed a hybrid system containing wind turbines, photovoltaic panels, electrolysis process, fuel cell, gas micro turbine and diesel generators. This system was simulated and was compared technically and economically to a system with only diesel gensets. The proposed hybrid system has a microrrede connected to a typical distribution system with a limited power demand value that prevents the satisfaction of all energy needs of the installation only with the utility power. This study evaluates the technical and economical impacts to meeting electric power consumption through this hybrid system and optimize using PSO, the design of this system that uses a dispatch order to manage the mini power generation units. The TRNSYS software was used due to its feature of allowing estimate the electric power and electric energy produced in one year apart with hourly details of each feature, considering actual estimates and localized availability of wind and photovoltaic resources.

A constituição de sistemas híbridos como alternativa ao fornecimento de energia da concessionária, gerando energia própria e operando de forma isolada ou interconectada ao sistema de distribuição, tem originado estudos e implementações em nível industrial, comercial e mais recentemente residencial. A principal discussão que surge são as análises das vantagens técnicas e econômicas pela opção desse tipo de instalação. Neste trabalho, é apresentado um estudo complementar às pesquisas realizadas, onde é projetado um sistema híbrido contendo aerogeradores, painéis fotovoltaicos, processo de eletrólise, célula a combustível, microturbina a gás e geradores diesel. Esse sistema é simulado e comparado técnica e economicamente a um sistema que contém apenas geradores diesel. O sistema híbrido proposto possui uma microrrede conectada a um típico sistema de distribuição mas com um limite de demanda contratada que impede a satisfação de todas as necessidades energéticas da instalação apenas com a energia da concessionária. Procura-se avaliar os impactos técnicos e econômicos do atendimento da demanda por eletricidade através deste sistema híbrido além de executar-se a otimização, via PSO, do dimensionamento deste sistema, que utiliza uma ordem de despacho para gerenciar as mini unidades geradoras de energia. Foi utilizado o software TRNSYS devido a sua característica de permitir estimar a potência e energia produzidas no intervalo de um ano com detalhamento horário de cada recurso, considerando estimativas reais e localizadas para a disponibilidade dos recursos eólicos e fotovoltaicos. / The designing of hybrid systems as an alternative to power supply from power utility, generating their own energy in operating islanded or grid-tie to the power utility, has resulted in studies and implementations in industrial, commercial and residential level recently. The main discussion that arises is the analysis of the technical and economical advantages for this type of solution. This work presents a complementary study to the researches conducted nowadays, which is designed a hybrid system containing wind turbines, photovoltaic panels, electrolysis process, fuel cell, gas micro turbine and diesel generators. This system was simulated and was compared technically and economically to a system with only diesel gensets. The proposed hybrid system has a microrrede connected to a typical distribution system with a limited power demand value that prevents the satisfaction of all energy needs of the installation only with the utility power. This study evaluates the technical and economical impacts to meeting electric power consumption through this hybrid system and optimize using PSO, the design of this system that uses a dispatch order to manage the mini power generation units. The TRNSYS software was used due to its feature of allowing estimate the electric power and electric energy produced in one year apart with hourly details of each feature, considering actual estimates and localized availability of wind and photovoltaic resources.

This research investigates the potential of a solar powered cooling system for single family houses in Pakistan. The system comprises water heating evacuated tube solar collectors, a hot water storage tank, and an absorption chiller. A literature review was carried out covering: • Energy situation, climate, and renewable energy potential in Pakistan; • Energy and thermal comfort in buildings, particularly for hot climates; • Solar collectors and solar cooling systems, particularly for hot climates; • Dynamic thermal simulation and weather data for solar energy systems and buildings. It was found that Pakistan is short of energy and that there is a great need to cool buildings. Renewable energy cooling systems are, therefore, of interest. The system described above was selected, as it was found that solar energy is abundant in Pakistan when cooling is required; thermal systems can be more economical than photovoltaics for hot climates and suitable components (collectors, absorption chillers, etc.) are commercially available. The TRNSYS dynamic thermal simulation program was selected as the main research tool, as it has been tested for solar energy and building applications by many researchers and suitable experimental facilities were not available. A simple typical building in Pakistan with a solar cooling system was simulated. Optimum values for key parameters were found by repeated simulations. It was concluded that the system would be able to provide cooling when required without an auxiliary heat source, and that an evacuated tube collector with a gross area of 12 m2, a collector flow rate of 165 kg/h, and a storage tank volume of 2 m3 would provide satisfactory performance for a 3.52 kW absorption chiller integrated with 42m3 single room. The results were in good agreement with published results from other researchers. Sensitivity analysis was carried out for the collector area, collector flow rate and storage tank size. It was found that varying the collector area had the largest effect on system performance, followed by varying the storage tank volume. Varying the collector flow rate had the smallest effect. It is recommended that solar cooling systems should be considered for Pakistan, and that further research should be carried out into reducing building cooling loads, using surplus heat for other loads, improving the performance of the proposed solar cooling system, and comparing it with other systems such as photovoltaics.

There has been a significant increase in the interest and implementations of heat pump systems for HVAC purposes in general and of ground source heat pumps (GSHPs) in particular. Though these systems have existed for decades, primarily in Europe, there has been an upward trend particularly in the United States in recent years. With the world-wide push toward CO2 emissions reduction targets, interest in heat pump systems to reduce CO2 emissions from heating and cooling is likely to only increase in the future. However, more than ever, financial considerations are also key factors in the implementation of any system. Ground source heat pumps (GSHPs) coupled to vertical borehole heat exchangers (BHEs) have been promoted as a viable heat pump system in climates where traditional air source heat pumps (ASHPs) may operate inefficiently. This type of system claims superior performance to ASHPs due to the relatively consistent temperature of the ground compared to the air, offering a higher temperature heat source in the heating season and a lower temperature sink in the cooling season. Projects designing and installing such a GSHP system have been implemented at large scales on several university campuses to provide heating and cooling. In this study, we aim to test the idea that a GSHP system, as a replacement for an existing CHP heating and conventional cooling systems, could reduce CO2 emissions, as well as provide a cost benefit to a large energy consumer, in this case the University of Massachusetts. This will be done using the existing heating and cooling loads provided by the conventional system and an established technique of modeling the heat pumps and BHEs. The GSHP system is modeled to follow the parameters of industry standards and sized to provide the best overall lifetime cost. The result on the overall annual costs, emissions, and university microgrid are considered.

Master's thesis "VRF system" aims on the energy simulation of energy needs for HVAC system of one floor of the FSI NetMe Research Centre building and followed evaluation of the advantage of using VRF system with heat recovery function. The first part is a theoretical introduction, which describes the basics of the mechanical refrigeration, following the differences and ways of functioning of the VRF system with heat recovery function. Practical part of this work is aimed on the description of the way of data input into the simulation tool. Finally, the results of the simulation and economical comparation of the VRF system and the existing four-pipe cold and warm water distribution system are presented

This master´s thesis is dealing with designing wireless management system for existing buildings. In the first part there is description of topologies a communication protocols used for wireless automation. Further there are characterized some devices for lighting, heating, ventilation and cooling regulation. These are used for a model network of a building management, where is system OpenHAB also presented. In the next chapter is aprissed specific edifice and its typical operation where is also designed basic and extended solution for it. This part continues with computation of energy consumption in TRNSYS software, that are used to calculate economic return for both variants.