Case Study
Las Vegas, Nevada
By:
Susan Farkas
Chika Nakazawa
Simona Tamutyte
Zhi-ya Wu
AAE/AAL 330
Design with Climate
Professor Alfredo Fernandez-Gonzalez
School of Architecture
University of Nevada, Las Vegas
Spring 2004
ABSTRACT
Climate conditions vary throughout the world. Outdoor spaces, like building interiors, may require
shading methods to provide comfortable areas for use. The importance of understanding the climate is
integral to the effective design strategies needed to shade and cool these spaces
The proposed study is an exercise for the AAE/AAL330 Design with Climate course at the University
of Nevada, Las Vegas. It is an analysis of outdoor shading devices and cooling strategies at the
Renaissance Center in Las Vegas, Nevada. By investigating a specific area within the complex area,
the existing outdoor design strategies for shading and cooling can be studied for its effectiveness and
alternate options can be suggested.
In conducting the experiment, the intent is to compare the conditions within and surrounding an open
courtyard, and to correlate these temperatures with the average activity level that occurs within and
around the courtyards. By using various scientific tools such as the HOBO data logger, the data
collected provides information of the space, the effectiveness of the comfort strategies, and how these
spaces relate to the temperature vegetation, material and people activities.
INTRODUCTION
The desert climate of Las Vegas, Nevada can have extreme weather conditions throughout the year.
Winters tend to be cool and windy, while summers temperatures reach 105º Fahrenheit (40º Celsius)
from May through September with a few days exceeding 115º Fahrenheit (46º Celsius). Most of the
annual 4 inches of rain fall occurs between January and March.
Table 1
Average Las Vegas Temperature Chart
Table 2
Average weather in Las Vegas, Nevada
Based on data reported by main weather stations
Monthly Averages
*
High
Temperature
(F/C)
Average
Temperature
(F/C)
Low
Temperature
(F/C)
Morning
Humidity (%)
Afternoon
Humidity (%)
Wind speed
(mph)
(meter/sec)
Wind Direction
Jan
Feb
Mar
Apr
May
Jun
Jul
57 / 14
63 / 17
68 / 20
77 / 25
87 / 31
100 / 38
105 /
41
45 / 7
49 / 9
55 / 13
63 / 17
72 / 23
82 / 28
33 / 1
38 / 4
44 / 7
50 / 10
60 / 16
55
51
45
35
32
28
23
7.4
8.5
3.31
WNW
Aug
Sep
Oct
Nov
Dec
103 /
40
94 / 35
82 / 28
67 / 20
57 / 14
88 / 31
86 / 30
78 / 25
66 / 19
52 / 11
45 / 7
69 / 21
76 / 25
74 / 23
66 / 19
54 / 12
42 / 6
33 / 1
32
24
28
33
34
36
45
53
16
14
11
15
17
17
20
27
32
10.1
11
11
11
10.2
9.6
9
8.1
7.8
7.3
3.8
4.52
4.92
4.92
4.92
4.56
4.29
4.02
3.62
3.49
3.23
WNW
SW
SW
SW
SW
S
SW
SW
WSW
WSW
WNW
* Orange region denotes the month study was conducted.
The Renaissance Center, located at the busy
northwest corner between Eastern Avenue and
Tropicana Avenue, is comprised of various
buildings with two major architectural styles
which were built in two major phases. The
old portion, which consists of many small
office areas linked by a series of courtyard,
and the new portion, which consists of big
office areas embellished by several
courtyards, displays two architectural
expressions of the Center.
Photograph 1: Renaissance Center
Both portions have outdoor courtyards which serve to link not only each building but also connect the
two distinct built phases of the center. Both phases utilize the courtyards for circulation not only
between the buildings, but also to link the two phases.
The Renaissance Center has a variety of interesting shading strategies used throughout the site. A
large open main courtyard at the newer portion of the Renaissance Complex became the focus of this
study. Situated in the newer phase of the complex, the concrete courtyard surrounded by grass and
flanked with trees on one side, seems to be an inviting place for employees and visitors to enjoy the
outdoors. The user friendly component of this space relies on the temperature and comfort level in and
around the courtyard.
The 20 ft. x 40 ft paved courtyard is
comprised of two sections, each having 4
concrete block benches and is situated along
the north-south axis. East of the courtyard,
a one story office complex sits
approximately 30 feet away with open space
between. Several trees line the western part
of the courtyard with a one story building
just beyond. Parking areas are north and
south of the courtyard, approximately 40 feet
from the courtyard. Walkways on the east,
north and south link the parking lots and
office buildings to the courtyard.
Photograph 2: Open space courtyard
During the initial site visit, several questions arose about the courtyard including the following:
• Does the shading provided by the trees help to cool the courtyard?
• Does the vegetation help with cooling the area?
• What occurs in the areas outside of the courtyard?
Based upon these questions and observations during this initial visit, the student research group
hypothesized that the temperature and comfort level is cooler within the courtyard than outside of the
courtyard. To test this hypothesis, equipment was placed in strategic areas to collect data pertaining to
the temperature, humidity and air velocity.
The results clearly supported the hypothesis statement - that the area within the courtyard was cooler
than that of the outer perimeter area. Additionally, the air velocity was effective in evaporative cooling
when temperatures became high.
HYPOTHESIS
The intent of this study is to examine the interior courtyard and its surrounding area and observe the
characteristics of comfort levels achieved with air temperature, relative humidity and air velocity.
The hypothesis is: The interior part of the courtyard, which is surrounded by trees on the
western side, is cooler than the outer eastern and northern perimeter areas outside of the
courtyard.
METHODS
Date:
Data was collected from four sources in and around the courtyard on March 22, 2004
between 9 am and 5 pm.
Location:
Renaissance Center open courtyard in new phase.
Equipment:
Four Hobo Data Sensors by Onset, Inc.
These measure temperature (T) and
relative humidity (RH). The collected data
can be downloaded to a computer
spreadsheet program for further analysis.
VELOCICALC Plus Meter by TSI, Inc.
Using a single probe (Pitot tube), this
handheld instrument simultaneously
measures logs various ventilation
parameters. Once collected, this data can
be downloaded to a computer
spreadsheet program.
For this study, the Velocicalc Plus Meter
was used to measure air velocity (V).
Equipment Placement:
Four HOBO data loggers were secured to the tops of 2”
posts that were rods that were placed in the following four
locations in and around the courtyard:
HOBO 1:
HOBO 2:
courtyard
HOBO 3:
courtyard
HOBO 4:
Inside the sitting area of the courtyard
Along the eastern walkway outside the
Along the northern walkway outside the
North of the courtyard near parking area
Additionally, the Velocicalc Plus Meter was taken to each
HOBO location to measure the air velocity at 15 minute
intervals.
Once collected, the data was downloaded and plotted to show correlations of temperature and comfort
levels. A final analysis was compiled to show the results.
Monitoring the Shade: Trees and buildings can provide shading and create cooler areas. Hourly
photographs of the four HOBO locations were taken by the student
researchers. The objective was to have visual data to track the shade in
the designated areas of study.
To prove the hypothesis, the study was conducted using methods of physical measurements and
calculations. The physical measurements included:
Table 3
EQUIPMENT & METHOD OF MEASURING DATA
EQUIPMENT
HOBO Data Logger
MEASUREMENT
Temperature ( T )
Relative Humidity ( RH )
Velocicalc Plus
Meter
Digital Camera
Air Velocity ( V )
UNIT
INTERVAL METHOD
F
%
every 5 minutes
Automatic
every 5 minutes
Automatic
m/s
every 15 minutes
Shading
every 1 hour
Student
Researcher
Student
Researcher
Once the information was gathered and downloaded, analysis of the data followed. The ASHRAE
Thermal Comfort Program was used to calculate the Standard Effective Temperature Index for the
adjusted shift in thermal comfort of the area.
RESULTS
SHADING
Photographs were taken every hour at the top of the hour to track the shading within the designated
space. The photographs resulted in showing the times that the HOBO areas were shaded:
Table 4
SHADING TIME TABLE
LOCATION
TIME AREA WAS
SHADED
HOBO 1
10AM - 5 PM
HOBO 2
2PM - 5 PM
HOBO 3
1PM - 5 PM
HOBO 4
5 PM
TEMPERATURE
Meteorological data for March 22, 2004 was reported at Las Vegas McCarran International Airport
(approx. 5 miles from Renaissance Center):
Table 5
Las Vegas 30 Year Temp. Averages & Records
March Monthly
Average/Records
March 22, 2004
Normal High (F / C)
68 / 20
70 / 21
Normal Low (F / C)
44 / 7
45 / 7
Record High (F / C)
91 / 33
87 / 31
Record Low (F / C)
23 / -5
32 / 0
Mean (F / C)
56 / 13
58 / 14
0.4
0
Normal Precip (in)
The collected Hobo data was downloaded and a graph was prepared to show the relationship between
the four locations.
Table 6
Temp (F)
Temperature: March 22, 9:00am - 5:00pm
140
120
100
80
HOBO 1
60
HOBO 2
HOBO 3
40
HOBO 4
20
9:
00
A
9: M
25
A
9: M
50
10 A M
:1
5
10 AM
:4
0
11 AM
:0
5
11 AM
:3
0
11 AM
:5
5
12 AM
:2
0
12 PM
:4
5
P
1: M
10
P
1: M
35
P
2: M
00
P
2: M
25
P
2: M
50
PM
3:
15
P
3: M
40
P
4: M
05
PM
4:
30
P
4: M
55
PM
0
time and day
HUMIDITY
According to the Hobo data, the humidity of the positions were almost the same.
Table 7
RH (%)
Relative Humidity: March 22, 9:00am - 5:00pm
45
40
HOBO 1
HOBO 2
35
HOBO 3
30
HOBO 4
25
20
15
10
5
9:
00
A
9: M
25
A
9: M
50
10 AM
:1
5
1 0 AM
:4
0
1 1 AM
:0
5
1 1 AM
:3
0
1 1 AM
:5
5
1 2 AM
:2
0
1 2 PM
:4
5
P
1: M
10
P
1: M
35
P
2: M
00
PM
2:
25
P
2: M
50
PM
3:
15
P
3: M
40
P
4: M
05
P
4: M
30
PM
4:
55
PM
0
time and day
AIR VELOCITY
The air velocity for each HOBO location indicates random and inconsistent numbers.
Table 8
Air Velocity
350
300
hobo 1
250
hobo 2
hobo 3
200
150
hobo 4
100
50
0
9:
00
9:
45
10
:3
0
11
:1
5
12
:0
0
12
:4
5
13
:3
0
14
:1
5
15
:0
0
15
:4
5
16
:3
0
Air speed (feet/min)
400
Time
COMFORT ZONE
Combining the hourly data of temperature (T), relative humidity (RH) and air velocity (V) and placing
them into the ASHRAE Thermal Comfort Program, the Standard Effective Temperature Index was
calculated. This index permits the comfort level to shift upward in the psychometric charts (Table 9)
The shift changes the average comfort level of 83º F to move upward to 86º F, primarily as a result of
the evaporative cooling from the air velocity that occurs at various times of the day.
Table 9
PSYCHOMETRIC CHARTS
HOBO 1
Outside comfort zone from 1pm – 2pm
HOBO 3
Outside comfort zone from 10am - 2pm
HOBO 2
Outside comfort zone from 11am – 2pm
HOBO 4
Outside comfort zone from 10am – 4pm
ANALYSIS
During the data collecting, each student researcher was assigned to spend 2 – 3 hours at the courtyard
between 9am and 5 pm. While collecting data throughout the day, noticeable temperature changes
were felt as the day progressed. Within the courtyard, under the shade, the temperature remained cool
and comfortable, while outside the courtyard the temperature felt warmer and less comfortable.
SHADING
•
•
•
•
HOBO 1 – Shading from the morning hours of 10 am and onward kept the area cooler
with the highest temperatures occurring at 1pm
HOBO 2 – Shade occurred in the mid afternoon hours of 2 pm onward. This caused
higher temperature conditions from 11 am – 2 pm.
HOBO 3 – Shade began to fall upon this area from 1pm onward, with the temperatures
dropping only after 3pm.
HOBO 4 – This area was exposed to the sun throughout the entire study period, from
9am – 5pm. Temperatures rose dramatically to over 100º F as early as
10am and remained extremely hot until 4pm.
The HOBO Data Loggers collected a broad range of temperature and relative humidity values. The
temperature data resulted in a quick analysis and understanding. The temperature graph (Table 6)
displays the varied values that each HOBO collected. The following analysis can be made:
VALUES
•
•
•
•
HOBO 1 - These values were dramatically different as the distance to the other
HOBOs became greater. The values between HOBO 1 and HOBO 4 were
the most extreme.
HOBO 2 – The values were fairly similar to HOBO 1 and HOBO 3.
HOBO 3 – The values were somewhat similar to HOBO 1 and HOBO 2.
HOBO 4 – These values were much higher than the rest of the HOBOs.
RELATIVE HUMIDITY
The relative humidity values were fairly constant inside and surrounding the courtyard throughout the
day, averaging 22.5%, +/- 0.5 %. The dryness of the desert climate supports the consistency that this
would be relatively constant.
AIR VELOCITY
Velocicalc Plus Meters measured the air velocity at each HOBO location. The rate of speed (m/s)
helped to create a cooler comfort zone during the hot times throughout the day. While some hours had
temperatures exceeding 83º F that is normally the maximum comfort level, the air velocity permitted
temperatures ranging from 83º F - 86º F to become an effective temperature comfort level.
CONCLUSIONS
The collected data and analysis supported the hypothesis that the inside courtyard was cooler in
temperature and had a more comfortable level while the areas outside the courtyard were warmer and
less comfortable. The temperature analysis showed that there is a difference in temperature range
between the HOBO locations due to the placement. The shading by the trees on the western side also
helped to cool the areas that became shaded. The relative humidity was consistent in all locations and
did not have as much effect on the cooling and comfort level as the shading did. Finally, the air
velocity played a major role by creating evaporative cooling and permitting temperatures exceeding
the 83º F to also become within the ranges of the comfort zone in the psychometric charts.
The information gathered and analyzed during this study can provide information for most of the mild
months of weather conditions at the Renaissance Center. Further studies may be conducted during
hotter months (May – September) which can help to understand how the courtyard can be best utilized
throughout the year. It may also be helpful to collect data for longer periods of time to establish more
precise information.
REFERENCES
(Las Vegas Climate Data)
http://www.city-data.com/city/Las-Vegas-Nevada.html
http://www.greatlasvegashomes.com/las_vegas_climatechart.htm
http://www.intellicast.com/
http://www.wunderground.com/