Sponsor
Portland State University. Department of Mechanical and Materials Engineering
First Advisor
Graig Spolek
Date of Publication
1-1-2011
Document Type
Thesis
Degree Name
Master of Science (M.S.) in Mechanical Engineering
Department
Mechanical and Materials Engineering
Language
English
Subjects
Green roofs (Gardening), Evaporative cooling, Soil moisture
DOI
10.15760/etd.125
Physical Description
1 online resource (vii, 57 p.)
Abstract
This study focuses on how green roof thermal performance is affected by the soil moisture in summer condition. It aims to determine whether moist soil is a better insulator during the summer months than dry soil. A soil model is developed to predict simultaneous conduction, convection, and surface evaporation for a layer of moist soil representing a green roof. It used to analyze evaporation process and its affect on the soil resistance. The model considers only bare soil without vegetation on the roof. The model predicts the soil surface temperature as it is affected by soil moisture content, which can then be used to calculate heat transfer through the soil layer. An experimental dry out test was conducted to measure the soil moisture and soil temperature histories. Comparison of the predicted and measured sol surface temperature shows that the model reasonably captures the actual behavior. The evaporative cooling effectively reduces the soil surface temperature and heat flux in moist soil and can be used as an effective way to insulate the roof.
Rights
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Persistent Identifier
http://archives.pdx.edu/ds/psu/6934
Recommended Citation
Liu, Ziyang, "Prediction of Soil Layer R-Value Dependence on Moisture Content" (2011). Dissertations and Theses. Paper 125.
https://doi.org/10.15760/etd.125
Comments
Portland State University. Dept. of Mechanical and Materials Engineering