The Radiant Heating markets - especially, the hydronic segment - are growing rapidly in North America due to homeowners' increasing demand for comfort and the steady rise in residential construction. Radiant systems are promising technologies for energy saving in commercial and residential building sectors together with improving occupant thermal comfort. Such a technology is different from the more standard all-air systems and thus can be termed Space Conditioning. However, the thermal performance of radiant systems in buildings has not been fully understood and accounted for. This is primarily due to lack of any standard testing mechanism. The central thrust of this paper is to experimentally investigate questions relating to thermal performance of radiant systems, thus also contribute towards evolving a new standard for testing mechanisms. Products from 12 different radiant floor systems were chosen from the market. Having defined each with similar control parameters such as flow rate, supply water temperature and similar design parameters like size, insulation etc., they are separately tested in a well insulated test setup. Experiments on the time variations for each test floor were performed at supply water temperatures ranging between 100F – 140F with a 10F increment at each stage. Having gathered data through the Data Acquisition System (DAS), the data is analyzed and compared between all systems. The paper concludes by providing recommendations for experimentally testing thermal energy performance, thermal uniformity and thermal stability of radiant floor heating technology. / Master of Science

[No abstract available] / Science, Faculty of / Botany, Department of / Graduate

Thesis (Ph. D.)--University of Texas at Austin, 2003. / Supervisor: John R. Howell. Vita. Includes bibliographical references. Available also from UMI Company.

No description available.

No description available.

No description available.

No description available.

Not available / text

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.