ARC 3682 : ENVIRONMENTAL TECHNOLOGY 2

SAMPLE EXAM
Spring 2001 / Grondzik


EXAM ONE

Instructions: this exam is closed-book; 1 hour and 15 minute duration. Write your name on the exam. You may refer to one 3" x 5" index card with your own notes -- but to no other materials. Read each question with care and be sure to answer all parts of multiple-part questions. Place all answers in the spaces provided and/or on the back of these sheets. You may circle or otherwise indicate answers where appropriate. Provide complete, precise, and legible answers. The numbers in parentheses indicate the relative point value of each question. There are 100 total points on the exam.

# 1. (10)

Provide a technically-sound explanation of thermal comfort that specifically addresses thermal comfort as a physiological/environmental phenomenon (as opposed to just an opinion). In this context, you should address why heat flow is important to thermal comfort, what means or mechanisms allow the body to achieve an appropriate net heat flow, and what specific physical factors (environmental and personal) will influence one's thermal comfort potential in any given building space.

 

 

 

# 2. (4)

Considering thermal comfort as a PHYSICAL phenomenon, what is the most important thing that an architect should remember about thermal comfort during the design of a building:

 

 

# 3. (10)

Provide a technically-sound explanation of thermal comfort that specifically addresses thermal comfort as a psychological-statistical phenomenon (as opposed to a physical condition). In this context, you should address how thermal comfort is "defined," how it is "measured," how the limits of thermally comfortable conditions are statistically established and presented, and how the resulting thermal comfort data are used in architectural design.

 

 

 

 

# 4. (4)

Considering thermal comfort as a PSYCHOLOGICAL/STATISTICAL phenomenon, what is the most important thing that an architect should remember about thermal comfort during the design of a building:

 

 

# 5. (9)

Measurements indicate that a sample of air has a dry bulb temperature of 70 deg F and a relative humidity of 50 %. By referring to the psychrometric chart (not included in this sample exam), determine numerical values and indicate measurement units for the following properties of this air sample ---

(A) specific humidity = ____________ (units: ___________________)

(B) wet bulb temperature = ______________ (units: _______________________)

(C) enthalpy = ______________ (units: ______________________)

(D) dew point temperature = ______________ (units: _____________________)

(E) Would condensation form on a soda can with a surface temperature of 50 deg F if it is brought into contact with this air sample? :

(1) Yes
(2) No
(3) Can not determine without knowing type of soda

 

# 6. (5)

Circle the entry in the first list that best describes the categories of air pollutant sources commonly found in buildings; circle the entry in the second list that best describes the most commonly used approaches to providing good indoor air quality.

SOURCE CATEGORIES   DESIGN APPROACHES
(A) occupants, outdoor air, activities   (a) filtration, adhesion, concentration
(B) occupants, visitors, equipment   (b) ventilation, filtration, source control
(C) occupants, materials, processes   (c) radiation, convection, conduction
(D) ducts, vents, fans   (d) barriers, connectors, filters

# 7. (6)

On the adjacent psychrometric chart, show how the following
psychrometric processes would be plotted (how they would appear):

(A) sensible heating

(B) sensible cooling and dehumidification

(C) evaporative cooling

 

# 8. (3)

Assuming identical climate conditions and surface area, which of the following roof constructions would have the HIGHEST (greatest) design heat loss ? :

(A) a concrete roof deck with absorptive gravel cover and a U-value of 0.10
(B) a concrete roof deck with reflective gravel cover and a U-value of 0.10
(C) a double layer tent-type roof membrane with a U-value of 0.20
(D) a wooden roof deck with asphalt shingles and a U-value of 0.05

 

# 9. (5)

Quick calculations during schematic design indicate that the design heat loss for a typical north- Florida slab-on-grade, two-story building for professional offices will be higher than allowed by the energy code. You are asked to suggest five separate and distinct ways in which the design heat loss might be reduced so that the building may be approved for construction. Suggest away .....

1.

2.

3.

4.

5.

 

#10. (3)

"Operative temperature" is BEST described as:

(A) the skin-surface temperature of a typical adult office worker
(B) the angle-weighted average surface temperature of room surfaces
(C) the average of dry bulb and mean radiant temperature
(D) the outside air temperature at which a building requires neither heating nor cooling

 

# 11. (5)

What design heat loss would occur through a west-facing glass window under the following conditions (SHOW all calculations) ---

outside air temperature = 20 deg F   inside air temperature = 70 deg F
window height = 5 feet   window width = 4 feet
U-value = 0.50   inside air film C = 1.5
outside air film R = 0.15    

 

#12. (3)

What does the abbreviation "MRT" stand for? Be specific.

 

 

#13. (3)

Which of the following statements best explains the difference between sensible heat and latent heat:

(A) latent heat involves temperature change while sensible heat involves moisture
(B) sensible heat involves temperature change while latent heat involves moisture
(C) latent heat involves time lag while sensible heat moves at the speed of light
(D) sensible heat is best sensed through vision while latent heat is best sensed through touch

 

# 14. (5)

Match each of the following heat loss descriptions to the heat loss equation that applies to that situation. Clearly cross out (strike through) the two heat flow situations that are listed but not represented by a corresponding equation. (Use letters or numbers to match -- not lines.)

HEAT FLOW SITUATIONS   EQUATIONS
(1) sensible heat loss through windows or skylights   (A) q = (U) (A) (delta t)
(2) sensible heat loss due to capacitive (time lag) effects   (B) q = (cfm) (1.1) (delta t)
(3) sensible heat loss through a wall or roof    
(4) latent heat loss due to air infiltrating into a space    
(5) sensible heat loss due to air infiltrating into a space    

 

#15. (4)

(A) The adjacent comfort zone chart is for people
wearing normal business clothes and engaged in
office-type activities. Clearly show how the comfort
zone might shift for people wearing bathing suits and
relaxing in a lounge chair in the shade.

(B) Label the vertical axis.

 

 

# 16. (5)

Five major assumptions are normally established for the calculation of design cooling load. One of these assumptions is that latent loads will be considered. List the other four assumptions:

 

#17. (5)

Match each of the following design cooling load situations with the equation with the equation that correctly applies to the situation. (Use letters or numbers to match -- not lines.)

HEAT FLOW SITUATIONS   EQUATIONS
(1) sensible load through opaque elements   (A) q = (number) (output) (CLF)
(2) sensible load due to air infiltrating into a space   (B) q = (cfm) (1.1) (delta t)
(3) radiation gain through transparent elements   (C) q = (cfm) (4840) (delta W)
(4) latent load due to air infiltrating into a space   (D) q = (A) (SHGC) (SHGF) (CLF)
(5) sensible load due to people   (E) q = (U) (A) (CLTD)

 

#18. (7)

Match each of the variables listed below with the measurement unit that is correctly associated with that particular unit. (The variables are the questions, the units are the answers. Use letters and numbers to match -- not lines.)

VARIABLES   UNITS
(A) insulation value of clothing   (1) met
(B) rate of heat flow   (2) (hr) (ft) (deg F) / Btu
(C) infiltration flow rate   (3) Btu / (hr) (ft) (deg F)
(D) U-value   (4) cfm
(E) R-value   (5) Btu / hr
(F) thermal measure of human activity   (6) (Btu) (inch) / (hr) (ft) (deg F)
(G) thermal conductivity   (7) clo

 

#19. (4)

Which (one or more) of the following aspects are included in the definition of acceptable indoor air quality developed by ASHRAE :

(A) the removal or elimination of airborne gases
(B) the limiting of relative humidity to less than 50%
(C) an expression of satisfaction by 80% or more of space occupants
(D) an absence of all known contaminants
(E) an absence of any smells or odors
(F) the control of contaminant concentrations to limits set by recognized authorities

 

Bonus Question: (3) [optional]

A young mechanical engineer who is doing the load calculations on a major project you have designed suggests that the latent loads from the lighting system are too high to comply with the requirements of ASHRAE Standard 90.1. What is your response to this comment?


Last updated 11 January 2001
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