Roof Sensing and Modeling - EEB Hub

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Project Information

Currently, about 20% of all energy in the US is used for heating and cooling of residential and commercial buildings. Attempts to improve the efficiency of this sector often target roofs due to their important contribution to thermal exchanges with the surrounding atmosphere. Green (vegetated) and cool (highly reflective) roofs are commonly assumed to provide energy savings due to a reduction in the cooling load; in addition, they clearly can help improve outdoor thermal comfort conditions in the summer by mitigating the urban heat island effect in highly urbanized regions. Nevertheless, their impact on annual energy consumption has yet to be rigorously studied and quantified in some US regions, such as the EEB area, where over 80% of the air conditioning energy is typically spent on heating, and only 20% on cooling. Cool roofs are especially critical since they reduce radiative absorption at the outer building walls in the heating season and will thus increase heating loads.

Using the campus of the Princeton Plasma Physics Laboratory (PPPL) as a test-bed, this project investigates and compares the different technologies for roof covers, and how their performance is affected by other parameters such as the thermal properties of the underlying roof material and the climate (and even meteorology) of the EEB region. We have installed sensors over several roofs (black and white, with different insulation depths). We are monitoring the roofs' thermal state and thermal fluxes, as well as the whole building cooling and heating energy consumption. We have also begun to couple this data with urban-building models to analyze the performance of these roofs, and in the process validate the models, which will then be applied to study different roof layering and combination options, the effect of other building parameters on the energetic impact of the roofs, and how these factors depend on the climatic conditions of the area. The coupled models capture the external interactions of the building more faithfully than most current building energy models; in addition, they ingest detailed meteorological data from the deployed sensors, including downwelling short and long wave radiation.

The expected outcomes are: 1) a comprehensive database of the measurements performed at the PPPL campus over different roof types, and 2) a suite of simulations using coupled urban-building models analyzing the performance of a wide range of roof surfaces and how it is affected by other building and climatic parameters. .

 

 

                    

 

last update on: November 07, 2011 17:55,  contact webmaster

Contact Information

Elie Bou-Zeid
Department of Civil & Environmental Engineering
Princeton University, C326 EQuad
Princeton, NJ 08544, USA

phone  :  +1-609-258-5429
fax        :  +1-609-258-2799
email   :  
ebouzeid@princeton.edu
web      :  
http://efm.princeton.edu/