Date of Graduation

5-2015

Document Type

Thesis

Degree Name

Bachelor of Science in Mechanical Engineering

Degree Level

Undergraduate

Department

Mechanical Engineering

Advisor/Mentor

Nutter, Darin

Abstract

For years, dark roofs have been used on residential and commercial buildings in all areas of the United States, but these roofs absorb large amounts of solar radiation, which can result in high cooling costs for the building. In some parts of the country, using a cool roof on a building is more beneficial because it will lower the energy consumption (and therefore will reduce energy costs) of heating and cooling the building. This paper summarizes the results from using the program eQUEST to analyze three different types of buildings – an office, a high school, and a hospital – in each ASHRAE climate zone to determine the economic impact of using a cool roof as opposed to a dark roof on these buildings. Three different reflectivities of roofs are chosen: a light roof (reflectivity of 0.6), a medium roof (reflectivity of 0.4), and a dark roof (reflectivity of 0.1), and several types of simulation results (utility charges, roof conduction, max HVAC heating and cooling load, and max hourly heating and cooling load) are collected from the simulations. According to the eQUEST simulations and assumed gas and electric rates, using a cool roof on a hospital anywhere in the United States increases the total energy consumption, and therefore is not advisable. In offices and schools in zones 4, 5, 6, and 7, and schools in zones 2 and 3, utilizing a cool roof may not be the most profitable investment; however, in many situations, it is economically viable. For schools in zone 1 and offices in zones 1, 2, and 3, utilizing cool roofs may be a good investment, depending on the company or school’s minimum attractive rate of return (MARR). When constructing a roof where the cost of a cool roof and non-cool roof are the same, utilizing a cool roof is the better option in offices in all zones and schools in all zones except zones 5, 6, and 7

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