A Two-Dimensional Numerical Analysis for Thermal Performance of an Intermittently Operated Radiant Floor Heating System in a Transient External Climatic Condition

Abstract

Building thermal inertia and operation control strategies have impacted on the thermal performance of a radiant floor heating system. This study conducts a two-dimensional numerical analysis of an intermittently operated radiant floor heating system using the Re-Normalization Group model with Discrete Ordinates Radiation model. A detailed numerical simulation setups and various analyses are provided, including grid independency analysis, initial condition, time step sizes and external boundary conditions. Three different weekend day intermittent operation strategies are investigated. The results showed that Case 3 designed with pre-heating of 20 h has better performance compared to Case 1 designed with pre-heating of 8 h and Case 2 designed with pre-heating of 14 h. The average indoor air temperature differences of approximate 2.1, 1.6 and 1.2 K are observed for Case 1, Case 2 and Case 3, respectively, when comparing two-time slot at 8:00am on Friday morning and Monday morning. This significantly highlights the effect of thermal inertia and the potential of energy saving due to the utilization of intermittent operation. Therefore, the current study presents numerical simulation potential in evaluating the radiant floor heating effects on indoor thermal environment, taking into account building thermal inertia and transient external climatic conditions.

Acknowledgments

The authors would like to express the gratitude for hosting by the University of Maryland and having the access to its computational resources and facilities.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Science Foundation of China (51608310), Science and Technology Plan Project of University in Shandong Province (J16LG07), Innovation Team of the Co-Innovation Center for Green Building of Shandong Province in Shandong Jianzhu University, and the Taishan Mountain Scholar Constructive Engineering Foundation of China.

Notes on contributors

Linhua Zhang

Linhua Zhang is a Professor in the School of Thermal Engineering at Shandong Jianzhu University, and Director of Shandong Key Laboratory of Renewable Energy Application Technology. He earned a Ph.D. degree from Xi’an University of Architecture and Technology, China in 2005. His research interests are building energy conservation and renewable energy application. He has published more than 100 journal and conference papers.

Jiying Liu

Jiying Liu is an Associate Professor in School of Thermal Engineering at Shandong Jianzhu University since 2014. He received his Ph.D. degree in the Heating, Ventilation and Air Conditioning from Southwest Jiaotong University in 2013. His research interests are urban microclimate environment and building energy consumption, renewable energy application, and heat and mass transfer. He has worked as postdoctoral research associate at the Pennsylvania State University, USA and research associate at University of Maryland, USA.

Mohammad Heidarinejad

Mohammad Heidarinejad is an Assistant Professor in the Department of Civil, Architectural and Environmental Engineering at IIT. His research interests center on the multi-scale modeling of building energy systems in the built environment focusing on their energy use patterns to provide healthy indoor and outdoor environments. He received his Ph.D. (2014) in Mechanical Engineering and M.Sc. (2011) in Architectural Engineering at the Pennsylvania State University. Previously he was a research assistant professor and research associate in the Mechanical Engineering Department at the University of Maryland College Park.

Moon Keun Kim

Moon Keun Kim is an Assistant Professor in Department of Architecture and Director of Building Physics Laboratory at Xi’an Jiaotong-Liverpool University, China. He received the Ph.D. degree from Swiss Federal Institute of Technology Zurich in 2014. His research interests are building science, sustainable and energy efficient buildings, energy and exergy analysis, low exergy and zero emission architecture. He has worked as Postdoctoral Researcher at Swiss Federal Institute of Technology Lausanne, and as a Research Assistant at the Pennsylvania State University, USA.

Jelena Srebric

Jelena Srebric is a Professor of Mechanical Engineering and Director of the Cluster for SustainabilITY in the Built Environment at the University of Maryland. She earned a Ph.D. degree from the Massachusetts Institute of Technology in 2000. The focus of her research is on multi-scale modeling of built infrastructure to provide reliable assessments of how these systems affect occupant population, energy consumption, and associated CO₂ emissions. She is the author and coauthor of roughly two hundred publications. The International Academy of Indoor Air Sciences recognized her work on indoor air quality with the 2005 Yaglou award. She was elected an international member of the Serbian National Academy of Engineering in 2013.