Award Date

December 2017

Degree Type

Thesis

Degree Name

Master of Science in Engineering (MSE)

Department

Mechanical Engineering

First Committee Member

Samir Moujaes

Second Committee Member

William Culbreth

Third Committee Member

Brendan O’Toole

Fourth Committee Member

Saaman Ladkany

Number of Pages

95

Abstract

Inlet and outlet conditions, Including size and location, have significant effects on the air distribution, temperature, humidity and thermal comfort in the buildings. In the current study, various strategies are presented for exhaust air vents and the effects of inlet and outlet vents locations are evaluated on providing thermal comfort in the residential and industrial buildings. To provide thermal comfort, three key factors need to be investigated based on ASHRAE standard 55- 2013 as follows: Comfort Zone, Thermal Sensation and Draft Rate. Flow distribution is studied as well in order to investigate the strategies, which make more vorticity in the ventilated air in living spaces as a factor of increasing discomfort in the building. The case study is located in Las Vegas where the weather is hot and dry in the summer time and the relative humidity is less than 8 %. In this regard, an evaporative cooling system is considered to increase humidity in the building since not only lack of humidity cause discomfort but also has many effects on breathing and skin dryness.

A Computational Fluid Dynamic (CFD) study is developed as a numerical solution for obtaining temperature profile, relative humidity profile in different sections of the building regarding the evaluation of Thermal comfort in most critical spaces. In this study, relative humidity definition is formulated and imported as a field function in STAR-CCM+ to track relative humidity in each points of the building. As the temperature of ventilated air increases by absorbing heat, the percentage of relative humidity will be decreased consequently inside the building. By evaluating various strategies of exhaust vents in different hours of the day, it can be concluded that the thermal comfort will be provided most appropriate if the exhaust vents in each room are on the intersection of ceiling with the middle of farthest walls from the room’s entrance in a building with a single evaporative cooler.

The results presented in this study can be used in the design of air conditioning systems in residential and industrial buildings, which leads to improvement in performance of air conditioning systems without any extra expenses.

Keywords

CFD; Evaporative cooler; Exhaust air vent; HVAC; Thermal comfort

Disciplines

Mechanical Engineering

Language

English


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