Date of Award

Spring 1-1-2012

Document Type

Thesis

Degree Name

Master of Science (MS)

First Advisor

Moncef Krarti

Second Advisor

Gregor P. Henze

Third Advisor

Junghyon Mun

Abstract

It is reported that the U.S. has seen a significant increase in energy consumption in recent years. According to Department of Energy (DOE), residential buildings in the U.S uses 36 percent more energy than it did 30 years ago (DOE, 2010). In the residential sector, 43 percent of the total energy consumption is used for space heating and space cooling. There is an increasing interest in improving the energy performance of buildings and especially in technologies to reduce building energy consumption for space heating and cooling. Radiant slab heating and radiant cooling systems have been used as alternative options to reduce heating and cooling energy use in residential buildings.

The study presented in this thesis focuses on the analysis of the performance of integrated radiant floor heating and ceiling cooling systems with embedded hot water pipes and chilled water pipes in the building slab. In particular, the study includes a comprehensive thermal analysis of radiant slab systems with two heat sources to perform as both radiant floor heating and ceiling cooling systems.

To perform the thermal analysis of the integrated radiant slab systems, a two-dimensional transient heat transfer model using implicit finite difference method (FDM) is developed. In addition, to estimate thermal loads for any conditioned zone, an RC network model is developed. Indoor air heat balance algorithm of Energyplus is adopted and implemented in combination with the developed FDM and the RC network model. In terms of control scheme of radiant systems, variable flow control algorithm of Energyplus is adopted.

Several sensitivity analyses and parametric analyses are performed to determine the transient thermal performance of the integrated radiant slab systems under various design and operating conditions. A numerical model of radiant slab has been developed to account for various insulation configurations. The predictions of the numerical model have been validated against reported experimental data. In addition, the results obtained from the developed numerical model for the integrated radiant floor heating and radiant ceiling cooling system have been verified against those with the obtained from Energyplus, a whole building energy simulation program. Using the developed integrated radiant floor and ceiling model, a series of parametric analyses is carried out to examine the transient thermal performance of radiant floor heating and radiant ceiling cooling system for various insulation configurations, building thermal mass, building zoning configurations, and climatic conditions.

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