Authors: Aaron Gentry and Sze Mun Lam
School: Mississippi State
|Abstract: This paper is an investigation of
an architectural response to regional climate conditions. The study focuses on a
vernacular typology of the Southeast known as the dog trot house. The traditional dog trot
house is characterized by two log houses with a central connecting passageway, a porch at
either side, and a chimney at each end. Developed in response to its environment, the dog
trot house is successful in providing cool shaded space in the Southeast's hot, humid
climate. This is accomplished primarily through its successful passive ventilation
This study attempts to identify, understand, and test the characteristics of the passive ventilation system using simple means available to anyone. The tests were conducted using the dog trot house located in French Camp, Mississippi as an example of this building type. Using an anemometer and a pendular wind measuring device of their own design, the students measured wind speed and direction on site during two days in March. Tests were also carried out on a scaled physical model.
Wind testing the scale model of the dog trot house at French Camp, Mississippi.
The results of the study show the geometry and orientation of the dog trot house to be extremely successful in creating passive ventilation. The north-south orientation of most dog-trot houses in the southeast takes advantage of prevailing wind patterns. The tall roof and solid spaces at either side of the breezeway create differential pressure as wind passes over and through the house. The differential pressure forces air to move through the central pasageway at a greater speed. Measurements show wind speeds at the central breezeway to be substantially greater than those at the exterior of the house. The authors feel the dog trot house should be considered an important prototype for designers concerned with energy efficiency.
Background: This study won second prize in the undergraduate division of the 1998 Vital Signs Student Case Study Competition. Professor Greenwood borrowed a Vital Signs equipment kit for the 1997-98 academic year. However, aside from an anemometer, the students developed their own testing devices for this study. Comments from the competition jury included:
"Very straightforward. The students clearly laid out their hypothesis and test methods. The tests, including the wind tunnel tests, were conducted carefully. Then they drew conclusions."
"They understand the limits of their study and are honest in presenting them."
"The study verifies the claims of a regionally recognized building."
"They assume air flow through the 'dog trot' will draw air through the adjoining rooms. But they didn't actually test this."
"They don't go into why this traditional strategy - that they show works - isn't used anymore. It would be interesting to know their thoughts about this."
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