Grantee Research Project Results

Final Report: Dynamic Energy Saving in Buildings with Underfloor Air Distribution System – Experimental and simulation studies

EPA Grant Number: SU834705
Title: Dynamic Energy Saving in Buildings with Underfloor Air Distribution System – Experimental and simulation studies
Investigators: Megri, Ahmed C. , Soleimani, Arash , Schulte, Brandon , Beghein, Claudine , Haghighat, Fariborz , Allard, Francis , Oun, Moftah , Zhang, Qing , Meyer, Ryan , Yu, Yao
Institution: University of Wyoming , University of La Rochelle , Concordia University
Current Institution: University of Wyoming , Concordia University , University of La Rochelle
EPA Project Officer: Page, Angela
Phase: I
Project Period: August 15, 2010 through August 14, 2011
Project Amount: $10,000
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet (2010) RFA Text |  Recipients Lists
Research Category: Pollution Prevention/Sustainable Development , P3 Awards , P3 Challenge Area - Air Quality , P3 Challenge Area - Sustainable and Healthy Communities , Sustainable and Healthy Communities

Objective:

The present study is aimed at seeking a better understanding of the thermodynamics involved with the air distribution strategies associated with UFAD systems and its impact on the cooling load dynamics. Thus objectives are:

• Experimental investigation of (a) UFAD plenum heat gain, (b) solar heat gain inward flowing fraction and (c) radiation-convection split of internal heat gains (with and without occupants) on the cooling load dynamics in a UFAD system,
• Development of a better understanding as to how each of the above factors impact the load dynamics during design of buildings with UFAD systems as opposed to conventional systems,
• Development of appropriate and novel methods to design and to analyze the cooling load,
• Quantitative estimation of the energy saving potential in practical applications

Summary/Accomplishments (Outputs/Outcomes):

A survey of a number of existing buildings in Quebec (Canada) has been performed. A comparison between the experimental data and FLUENT CFD software has been performed.

At University of Wyoming, an experimental room has been equipped with an UFAD system (heating and cooling unit with an outside condensing unit), as well as raised floor system with diffusers and return grille. First, this HVAC project has been designed and used by architectural engineering undergraduate students to demonstrate the HVAC design process and how multiple trades (plumbing, electrical, mechanical) are integrated. Secondly, we performed instrumentation, in which data logging, as well as temperature and airflow sensors are installed in surface and air locations. The temperature thermocouples are produced and calibrated by the students.

A zonal model (POMA) has been developed in the frame work of the project. Zonal models are an intermediate approach between simplified one node models (such as DOE, EnergyPlus, ESP-r) and slow computational fluid dynamics programs (such as Star-CD, FLUENT and FLOVENT).

Conclusions:

UFAD system is mainly used for cooling applications, especially in commercial buildings. However, a very few research investigated the use of UFAD for heating residential homes. Our objective was to investigate the feasibility of UFAD in residential house for both cooling and heating applications.

The comparisons between the home experimental results and the two models POMA and FLOVENT (as well as the comparison between the high-rise building and FLUENT software at Montreal) are in agreement. However, more research is necessary to improve the model predictions: models calibration and extensive experimental work in a well-equipped environmental chamber to investigate the thermal radiation-convection distribution in a room equipped with the under floor ventilation system as well as comfort and indoor air quality.

From the 3 case studies, we conclude that the gradient of temperature within the room can be acceptable in some situations. In Phase II, optimization of UFAD system design will be performed, using the actual experimental building, as well as zonal and CFD models.

Supplemental Keywords:

Indoor air, human health, sustainable development, waste reduction, energy conservation, modeling, simulation, monitoring, analytical, surveys, measurement methods, design, thermal comfort, built environment