The Impact of Microclimate on Thermal Comfort

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The Impact of Microclimate on Thermal Comfort

• Risman Plaza
• Kent, Ohio

Mark Blaser Greg Struna
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Risman Plaza location

Kent State University Campus Map
Risman Plaza (red)
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Risman Plaza

• Designed by Richards, Bauer Moorhead,
  Architects Engineers of Toledo, Ohio
• Built as part of the current Kent State Student
  Center and constructed in 1972
• Serves as an outdoor common area between the
  Student Center and the main Library
• An L shaped plaza, about 2 acres in size
• Typical building height around plaza is 40-50
  feet tall, except the library tower which is
  approximately 160 feet tall.
• All buildings surrounding the plaza are clad in
  brick and the plaza is paved in brick and
  concrete with planting beds mixed in.

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Design Intent of Plaza

• The plaza is an outdoor common area on campus
  which serves as a gathering place for the
• university community.

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Research Questions

• Does the design of Risman Plaza create a
  microclimate that affects the thermal comfort of
  the space?
• Does the wind velocity inside the plaza differ
  from the wind outside?
• How turbulent are those winds?
• What impact does the vegetation in the plaza have
  on thermal comfort?

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Microclimate

• Microclimate - the climate of a small location
  within an area as compared with the climate of
  the entire region.
• Local features such as buildings creates
  variations in the microclimate which should be
  considered when designing.

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Microclimate

• One of the main reasons for considering
  microclimate in the design of outdoor spaces is
  to create thermally comfortable spaces.
• Four climatic conditions
• Temperature gt difficult to affect
• Humidity gt difficult to affect
• Wind velocity gt can be affected
• Mean Radiant Temperature gt can be affected

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Thermal Comfort

• Six factors that affect thermal comfort
• Temperature
• Wind Velocity
• Mean Radiant Temperature
• Humidity
• Clothing Insulation Factor
• Metabolic Heat Rate

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To create a space that affects the microclimatic
conditions in a way that improves thermal comfort
is the goal of an outdoor gathering space.

This can be accomplished by using the buildings
to create a microclimate that brings sunlight and
blocks the wind in winter and reduces the amount
of sunlight and brings in a gentle wind in the
summer. (Brown, DeKay, 2001)
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Hypothesis

• Increased wind velocity in early spring
  reduces thermal comfort in Risman Plaza.

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Method Process

• Data Analyzed
• Wind Gust
• Wind Velocity (Average of 1 min.)
• Solar Radiation (Mean Radiant Temperature)
• Dry Bulb Temperature
• Humidity
• Surveys
• Silver Meadows Weather Station Data

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Data Tools

• Kestrel 4000 Pocket Weather Tracker
• Measures
• Dry Bulb Temperature
• Humidity
• Wind Gust
• Wind Velocity

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Data Tools

• Globe Thermometer
• Measures
• Mean Radiant Temperature
• Construction
• RadioShack Indoor/Outdoor
• Digital Thermometer.
• Ping Pong Ball
• Spray Painted Matte Black and attached to
  outdoor sensor.

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Data Collection

• Data Collection Days
• Three consistent times
• 900A.M. 100P.M. 500P.M
• Data Set 1 (Winter Conditions)
• Date range 03/03/05 03-14-05
• Data Set 2 (Spring Conditions)
• Date range 04/06/05 04-15-05

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Data Location Points (17)
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(No Transcript)
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Prevailing Wind Direction
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Predominant Wind Direction
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AVERAGE
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900 4/09/05
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1200 4/09/05
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500 4/09/05
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Surveys

• 10 Questions
• First questions set subjects into a demographic.
• ASHRAE seven point thermal comfort scale.
• Last question is to determine which factors are
  affecting the subjects thermal comfort.
• Wind, Temperature, Solar radiation, Humidity

ASHRAE Thermal Sensation Scale
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Survey Results

• Data Set 1 - Winter (23 total)
• (3/10/05) 1200P.M.
• 9 surveys collected
• Average Mean Vote -2.2 (Cool)
• Largest Factor Out of 9 subject who ranked
  which factors were affecting their comfort the
  most
• 6 (67) ranked wind velocity the greatest
  factor
• 3 (33) ranked temperature the greatest factor
• In all 9 surveys wind speed and temperature were
  first or second ranked
• Atmospheric Science Thermal Comfort Calculator
• Predicted Mean Vote based on measurements
• -2.4 (Cool)
• Predicted Percentage Dissatisfied 92.0

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Survey Results

• Data Set 2 Spring (20 total)
• (4/9/05) 1200P.M.
• 20 surveys collected
• Average Mean Vote -1.2 (Slightly Cool)
• Largest Factor Out of 14 subject who chose to
  rank which factors were affecting their comfort
  the most
• 12 (85) ranked wind velocity the greatest
  factor
• Atmospheric Science Thermal Comfort Calculator
• Predicted Mean Vote based on measurements
• -1.4 (Slightly Cool)
• Predicted Percentage Dissatisfied 44.5

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Winter Comfort
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Spring Comfort
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Buildings and Wind

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Solution

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REFERENCES

• Brown, Robert Gillespie, Terry J. (1995)
  Microclimatic Landscape Design Creating Thermal
  Comfort and Energy Efficiency. Wiley Sons,Inc
  New York
• Chang, Cheng-Hsin Meroney, Robert N. (2003)
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• de la Flor, Francisco Sánchez Domínguez,
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• Dimoudi, Argiro Nikolopoulou, Marialena. (2003)
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REFERENCES

• Longley, I.D., et al. (2004) Short-term
  measurements of airflow and turbulence in two
  street canyons in Manchester. Atmospheric
  Environment, vol. 38. 1. 69.
• Nikolopoulou, Marialena Baker, Nick. (2001)
  THERMAL COMFORT IN OUTDOOR URBAN SPACES
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• Olgyay, V. (1963). Design with Climate
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• Picot, X. (2004) Thermal comfort in urban spaces
  impact of vegetation growth
• Case study Piazza della Scienza, Milan,
  Italy. Energy Buildings, vol. 36. 4. 329.

• Sharag Eldin, Adil. (2001) Analysis of Thermal
  Comfort Requirements of the Elderly in
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• Zacharias, John Stathopoulos, Ted Wu, Hanqing.
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  296.

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Hypothesis

• Increased wind velocity in early spring
  reduces thermal comfort in Risman Plaza.