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Creating a sense of place through a comfortable indoor condition is a goal of the architectural design process. Thermal comfort is an important component of this condition. To achieve thermally comfortable environments mechanical systems such as Radiant Cooling (RC) could be used. RC systems have potential benefit of lower energy consumption when compared to other common cooling, ventilating and air-conditioning systems. Decisions related to the use of mechanical systems such as these should be considered in the early stages of design to maximize the building performance through systems integration and minimize redesign as part of the design process. RC systems have several special demands and related variables. Architects, HVAC system engineers, and decision-makers have to understand these issues and variables and their impact on the other building performance mandates. Through this understanding, these professionals can better evaluate tradeoffs to reach the desired solution of the design problem. Unfortunately, in the United States few architects and engineers have experience with RC systems which in turn limits the application of these systems. Through systematic literature review, a series of case studies, and interviews with experienced professionals, this research captures and structures knowledge related to how decisions are made concerning RC systems. Through this knowledge capturing procedure, the relevant design performance mandates, barriers and constraints, and potential advantages and benefits of radiant cooling systems are determined and mapped to a decision-support framework. This framework is graphically presented which may later be translated to a decision-support software package which could then be developed as a radiant cooling system design assistance tool for architects and HVAC engineers. / Ph. D.

<p>Part I of this thesis is a theoretical background to parts II and III.</p><p>Part II treats the phenomenon of decreased visibility through a glazing due to external water condensation, dew, on the external surface. Some simulations are presented where it is shown that under certain circumstances condensation can be expected. A combination of coatings on the external surface is suggested to overcome the problem of external condesation. It consists of both a coating which decreases the emissivity of the surface and a hydrophilic coating which reduces the detrimental effects to the view through the window.</p><p>Fresnel calculations of the optical properties are used to discuss the feasibility of using different coatings. A new test box was used to verify that the proposed window coatings perform as expected.</p><p>Part III is a study on the angular dependence of solar absorptance in windows. Optical properties vary with the angle of incidence of the incoming light. The variation is different from one window pane to another. </p><p>A model is proposed to approximate the angular variation of the solar absorptance in window panes. The model is semi-empirical and involves dividing the wide range of windows into nine groups. To which group a window belongs, depends on how many panes it has and on the features of the outer pane. The strength of the model is that it can be used without knowing the exact optical properties of each pane of the window. This makes it useful in the many cases when these data are not given by the manufacturer and Fresnel calculations to get the optical properties of the window are not feasible. The model is simple and can be added as an appendix to existing standards for measuring optical properties of windows.</p>

Radiant heating and cooling has a reputation of increasing the comfort level and reducing the energy consumption of buildings. The main advantages of radiant heating and cooling are low operational noise and reduced fan power cost. Radiant heating and cooling has been supplied in several forms, including floor heating, ceiling heating and cooling, radiant panels and façade heating and cooling. Among them, façade heating and cooling is the most recently developed system. This dissertation provides a comprehensive study of several technical issues relative to radiant heating and cooling systems that have received little attention in previous research. The following aspects are covered in this dissertation: First, a heat transfer model of mullion radiators, one type of façade heating and cooling, is developed and verified by measured performance data. The simulation demonstrates that the heating or cooling capacity of mullion radiators is a semi-linear function of supply water temperature and is affected by the thermal conductive resistance of mullion tubes, the room air temperature, the supply water flow rate, and the outside air temperature. Second, the impact of the positions of radiators on energy consumption and thermal comfort is studied. This dissertation compares the heating load and comfort level as measured by uniformity of operative temperature for two different layouts of radiators in the same geometric space. The air exchange rate has been identified as an important factor which affects energy saving benefits of the radiant heating systems. Third, the infiltration and the interaction of infiltration and mechanical ventilation air to produce moisture condensation in a radiantly cooled office are examined. The infiltration of the studied office is also explored by on-site blower door measurement, by analyzing measured CO2 concentration data, and through modeling. This investigation shows the infiltration level of the studied office to range between 0.46 and 1.03 air changes per hour (ACH). Fourth, the integrated sensible heating and cooling system is simulated and compared with a single duct variable air volume (VAV) system. The results show that, at the current infiltration level, the studied sensible heating and cooling system with an integrated active desiccant ventilation unit consumes 5.6% more primary energy than a single duct VAV system; it would consumes 11.4% less primary energy when the system is integrated with a presumed passive desiccant ventilation unit.

Radiant heating and cooling has a reputation of increasing the comfort level and reducing the energy consumption of buildings. The main advantages of radiant heating and cooling are low operational noise and reduced fan power cost. Radiant heating and cooling has been supplied in several forms, including floor heating, ceiling heating and cooling, radiant panels and façade heating and cooling. Among them, façade heating and cooling is the most recently developed system. This dissertation provides a comprehensive study of several technical issues relative to radiant heating and cooling systems that have received little attention in previous research. The following aspects are covered in this dissertation: First, a heat transfer model of mullion radiators, one type of façade heating and cooling, is developed and verified by measured performance data. The simulation demonstrates that the heating or cooling capacity of mullion radiators is a semi-linear function of supply water temperature and is affected by the thermal conductive resistance of mullion tubes, the room air temperature, the supply water flow rate, and the outside air temperature. Second, the impact of the positions of radiators on energy consumption and thermal comfort is studied. This dissertation compares the heating load and comfort level as measured by uniformity of operative temperature for two different layouts of radiators in the same geometric space. The air exchange rate has been identified as an important factor which affects energy saving benefits of the radiant heating systems. Third, the infiltration and the interaction of infiltration and mechanical ventilation air to produce moisture condensation in a radiantly cooled office are examined. The infiltration of the studied office is also explored by on-site blower door measurement, by analyzing measured CO2 concentration data, and through modeling. This investigation shows the infiltration level of the studied office to range between 0.46 and 1.03 air changes per hour (ACH). Fourth, the integrated sensible heating and cooling system is simulated and compared with a single duct variable air volume (VAV) system. The results show that, at the current infiltration level, the studied sensible heating and cooling system with an integrated active desiccant ventilation unit consumes 5.6% more primary energy than a single duct VAV system; it would consumes 11.4% less primary energy when the system is integrated with a presumed passive desiccant ventilation unit.

Part I of this thesis is a theoretical background to parts II and III. Part II treats the phenomenon of decreased visibility through a glazing due to external water condensation, dew, on the external surface. Some simulations are presented where it is shown that under certain circumstances condensation can be expected. A combination of coatings on the external surface is suggested to overcome the problem of external condesation. It consists of both a coating which decreases the emissivity of the surface and a hydrophilic coating which reduces the detrimental effects to the view through the window. Fresnel calculations of the optical properties are used to discuss the feasibility of using different coatings. A new test box was used to verify that the proposed window coatings perform as expected. Part III is a study on the angular dependence of solar absorptance in windows. Optical properties vary with the angle of incidence of the incoming light. The variation is different from one window pane to another. A model is proposed to approximate the angular variation of the solar absorptance in window panes. The model is semi-empirical and involves dividing the wide range of windows into nine groups. To which group a window belongs, depends on how many panes it has and on the features of the outer pane. The strength of the model is that it can be used without knowing the exact optical properties of each pane of the window. This makes it useful in the many cases when these data are not given by the manufacturer and Fresnel calculations to get the optical properties of the window are not feasible. The model is simple and can be added as an appendix to existing standards for measuring optical properties of windows.

The diploma thesis is consisting of theoretic part, which deals with used ventilating systems, describes basic types of air-conditioning systems and basic characteristics and diversification of radiant cooling systems. Following part attend to design of ventilating system and radiant cooling system for cooling of the flat. Design of the ventilation systém is based on minimum air flow per person. Design of the radiant cooling system is based on calculation of thermal loads. Design documentation is part of the diploma thesis as well as the calculations made in excel.

O presente trabalho é um estudo para a determinação de índices de ajuste em medidas efetuadas por sensores de temperatura do ar utilizadas em algoritmos de controle do sistema de automação do sistema de condicionamento de ar do tipo \"Teto Frio\". É um trabalho experimental baseado na coleta de dados de diversas variáveis ambientais em um laboratório que utiliza este tipo de sistema. Esse laboratório possui um sistema de climatização misto composto por circuitos de água gelada que percorre serpentinas instaladas em placas metálicas de forro, para troca de calor por radiação (retirada de calor sensível) e circuitos de ar, com distribuição de ar pelo teto, para troca de calor por convecção (retirada de calor latente). Seu funcionamento é controlado por um sistema de automação (hardware e software) específico. Este estudo pretende determinar índices de ajuste que, introduzidos nos algoritmos de controle do sistema de automação, corrijam as leituras de temperatura do ar realizadas no ambiente por sensores do sistema posicionados em locais que, embora esteticamente sejam os mais adequados, funcionalmente, não o são. Os resultados, concluídos através de método estatístico e recursos de representação gráfica, promoverão além do melhor entendimento das condições térmicas do ambiente oferecidas pelo sistema de \"teto frio\", a otimização da operação do sistema, isto é, a melhoria do conforto para os ocupantes e a conservação de energia. / The present work is a study to determine adjustment indexes in measurements made by air temperature sensors used in control algorithms of automation system applied to \"Cooling Ceiling\" air conditioning system. It is an experimental work based on data collection of several environmental variables at a laboratory which uses this kind of system. This laboratory owns a mixed air conditioning system compounded by chilled water circuits which pass through coils installed on metal ceiling tiles, for heat exchange by radiation (sensitive heat withdrawal), and air circuits with distribution by ceiling, for heat exchange by convection (latent heat withdrawal). Its functioning is controlled by a specific automation system (hardware and software). This study intends to determine adjustment indexes which, added in system control algorithms correct the air temperature readings accomplished in the environment by system sensors located in places that, although aesthetically are more suited, functionally are not. The results, concluded through statistic methods, and graphic representation researches, will promote beyond better understanding of thermal conditions of environment offered by this cooling ceiling system, optimization of system operation, that are a better comfort for the occupants and the energy saving.

O presente trabalho é um estudo para a determinação de índices de ajuste em medidas efetuadas por sensores de temperatura do ar utilizadas em algoritmos de controle do sistema de automação do sistema de condicionamento de ar do tipo \"Teto Frio\". É um trabalho experimental baseado na coleta de dados de diversas variáveis ambientais em um laboratório que utiliza este tipo de sistema. Esse laboratório possui um sistema de climatização misto composto por circuitos de água gelada que percorre serpentinas instaladas em placas metálicas de forro, para troca de calor por radiação (retirada de calor sensível) e circuitos de ar, com distribuição de ar pelo teto, para troca de calor por convecção (retirada de calor latente). Seu funcionamento é controlado por um sistema de automação (hardware e software) específico. Este estudo pretende determinar índices de ajuste que, introduzidos nos algoritmos de controle do sistema de automação, corrijam as leituras de temperatura do ar realizadas no ambiente por sensores do sistema posicionados em locais que, embora esteticamente sejam os mais adequados, funcionalmente, não o são. Os resultados, concluídos através de método estatístico e recursos de representação gráfica, promoverão além do melhor entendimento das condições térmicas do ambiente oferecidas pelo sistema de \"teto frio\", a otimização da operação do sistema, isto é, a melhoria do conforto para os ocupantes e a conservação de energia. / The present work is a study to determine adjustment indexes in measurements made by air temperature sensors used in control algorithms of automation system applied to \"Cooling Ceiling\" air conditioning system. It is an experimental work based on data collection of several environmental variables at a laboratory which uses this kind of system. This laboratory owns a mixed air conditioning system compounded by chilled water circuits which pass through coils installed on metal ceiling tiles, for heat exchange by radiation (sensitive heat withdrawal), and air circuits with distribution by ceiling, for heat exchange by convection (latent heat withdrawal). Its functioning is controlled by a specific automation system (hardware and software). This study intends to determine adjustment indexes which, added in system control algorithms correct the air temperature readings accomplished in the environment by system sensors located in places that, although aesthetically are more suited, functionally are not. The results, concluded through statistic methods, and graphic representation researches, will promote beyond better understanding of thermal conditions of environment offered by this cooling ceiling system, optimization of system operation, that are a better comfort for the occupants and the energy saving.

The master’s thesis deals with optimization of cooling system of family house using borehole heat exchanger as a single cooling source. In the experimental part of the thesis was carried out long-term mearurements. The main part of the master’s thesis is the development and verification mathematical and physical model of thermal behavior chilled room. The result are computer simulations and evaluation of individual scenarios and design requirements for a potential optimization of measurement and control system. The theoretical part generally deals with radiant cooling systems.