ARC 3682 : ENVIRONMENTAL TECHNOLOGY 2

SAMPLE EXAM
Spring 2001 / Grondzik


EXAM TWO

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 (plus 2 bonus questions).

 

# 1. (8)

The existing open courtyards between the wings of the School of Architecture building are likely to be fully enclosed in glass to provide conditioned atrium spaces for circulation, exhibits, and relaxation. List the FOUR HVAC system selection issues (factors or concerns) that you believe would be MOST important for an architect or engineer to consider when choosing an HVAC system for these particular spaces. Using proper wording, convert each issue into an appropriate selection criterion.

SELECTION ISSUE or CONCERN   RELATED SELECTION CRITERION
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# 2. (6)

CIRCLE those statements in the list below that should be included in a correct description of how a vapor compression refrigeration system operates to provide cooling. Strike through those statements that have no relationship to the operation of such a system.

(A) the compressor is activated by heat from a process, a solar collector, or a boiler
(B) hot refrigerant vapor from the compressor flows to the condenser (coil)
(C) hot refrigerant liquid from the condenser flows to the expansion valve
(D) a cool mixture of refrigerant vapor and liquid flows to the evaporator (coil)
(E) the evaporator accepts heat from the building and vaporizes all remaining liquid refrigerant
(F) refrigerant vapor flows to the compressor where it is raised to a higher pressure
(G) a small amount of refrigerant is expelled from the loop each cycle to provide latent cooling

 

# 3. (15)

Match each of the functions listed below with the item of mechanical equipment (from the adjacent list) that would normally provide that specific function in a typical building. (Note that listed equipment items may be used more than once or not at all). Do NOT use connecting lines to answer.

FUNCTION   EQUIPMENT ITEM
(A) control the amount of return & outdoor air entering an AHU   (1) valve
(B) heat air in a residential central heating system   (2) heat pump
(C) clean air in an HVAC system   (3) furnace
(D) generate cool water for use in AHU cooling coils   (4) duct
(E) serve as a container for the distribution of air   (5) diffuser
(F) serve as a delivery device in an all-air heating system   (6) boiler
(G) serve as a delivery device in an all-water heating system   (7) pipe
(H) serve as a container for the distribution of steam   (8) filter
(I) provide the force to circulate air in a ductwork system   (9) chiller
(J) heat water in a central heating system   (10) unit heater
(K) to automatically control the operation of an HVAC system   (11) thermostat
(L) control the flow of water in a pipe   (12) damper
(M) provide the force to circulate water in a piping system   (13) cooling tower
(N) dump heat from within a building to the outside environment   (14) fan
(O) extract heat from the outside environment to heat a building   (15) pump

 

# 4. (4)

Assume that you are dealing with someone who clearly understands the operation of a vapor compression refrigeration cycle. In the space below, explain to that person how a Aheat pump@ works.

 

 

 

# 5. (4)

To be correctly called an air-conditioning system, ASHRAE says that a climate control system must be able to accomplish FOUR things simultaneously. These four things are:

 

# 6. (4)

An architect is considering different ways to reduce peak morning (10 AM) cooling load through an EAST-facing curtain-wall. Three possible strategies have been identified:

(1) adding wall insulation to reduce the U-value by 50%;
(2) replacing the dark exterior wall finish with a light-colored finish;
(3) substantially increasing the mass of the wall construction.

Based upon this background information, circle the statement or statements in the list below that actually are CORRECT:

(A) strategy (1) will reduce the 10 AM cooling load by approximately 50%, and will also reduce the cooling load through the wall at other times of the day by a similar amount

(B) strategy (2) will reduce the 10 AM cooling load by 30-50%, but may cause the cooling load through the wall during the afternoon hours to increase slightly

(C) strategy (3) will reduce the 10 AM cooling load, but will probably cause the cooling load through the wall during the afternoon hours to increase slightly

(D) because strategy (1) does not affect the CLTD value for the wall it will have no effect on the 10 AM cooling load

(E) strategy (2) will reduce the 10 AM cooling load by 30-50%, and will reduce the cooling load at other times of the day -- although afternoon/evening reductions will not be as great

(F) strategy (3) will reduce the 10 AM cooling load, and will reduce the cooling load through the wall at all other times of the day by a similar amount

(G) strategies (1), (2), and (3) are effective strategies if applied separately, but will cause an increase in 10 AM cooling load through the wall if they are all used together -- due to the little-discussed capacitive-inductance effect

 

# 7. (20)

Schematic diagrams of several different HVAC systems are presented below and on the following page. Sufficient information is provided to permit each diagram to be positively identified as representing a distinct type of HVAC system. For each system, indicate the name of the system, the system type (all-air, all-water, air-water, or local), a reason (a positive characteristic) why such system might be considered for use in the studios in the remodeled School of Architecture, a performance or comfort concern (potential problem ) if the system were used in the studios, and what you feel is the most important Aarchitectural@ design issue related to use of such a system in a School of Architecture studio.

SYSTEM 1 --

System Name:
System Type:
Reason to Consider Using:
Concern if System Used:
Key Architectural Design Issue:

 

 

SYSTEM 2 --

System Name:
System Type:
Reason to Consider Using:
Concern if System Used:
Key Architectural Design Issue:

 

 

SYSTEM 3 --

System Name:
System Type:
Reason to Consider Using:
Concern if System Used:
Key Architectural Design Issue:

 

 

SYSTEM 4 --

System Name:
System Type:
Reason to Consider Using:
Concern if System Used:
Key Architectural Design Issue:

 

 

SYSTEM 5 --

System Name:
System Type:
Reason to Consider Using:
Concern if System Used:
Key Architectural Design Issue:

 

 

# 8. (3)

The term "DX", used in the context of a climate control (HVAC) system, refers to:

(A) any district-wide expansion of a large chiller system
(B) Diethyl-Xylene, a refrigerant with serious climate change (global warming) potential
(C) Diethyl-Xylephene, a desiccant commonly used in absorption chillers
(D) a direct expansion cooling coil (where refrigerant flows through the evaporator coil)

 

# 9. (5)

It is reasonable to argue that the design professional BEST able to establish thermal zones for a building under design is the ARCHITECT -- and not the mechanical consultant. Provide a convincing argument in support of the contention that the architect should be the design professional who thermally zones a building:

 

 

 

#10. (9)

Draw a schematic diagram of a vapor compression (mechanical)
refrigeration CYCLE in the space adjacent. Show and label all critical
components and indicate how these components are interconnected
(including direction of refrigerant flow).

Using the letters below as labels, indicate which of the components
in the sketch above perform the following functions:

(A) provides a controlled pressure drop so that refrigerant will cool itself
(B) removes heat from the refrigerant loop for disposal to the outside air
(C) removes heat from air or water so that building spaces can be cooled
(D) uses electricity to pressurize and circulate refrigerant

 

# 11. (3)

Which of the following key components of a building cooling system must always be located outside of a building (external to the building envelope):

(A) the air-handling unit
(B) the compressor
(C) the cooling coil
(D) the cooling tower or air-cooled condenser
(E) the servo-compensation mechanism
(F) the thermostat

WHY is this the case? :

 

#12. (6)

Match each of the following terms with the description that best explains the particular term. Do NOT use connecting lines to answer.

TERM   DESCRIPTION
(A) shading coefficient   (1) air going back to an air handling unit from a room
(B) efficiency   (2) a measure of shading device effectiveness
(C) return air   (3) general system output relative to system input
(D) ton   (4) a measure of cooling system capacity
(E) cfm   (5) refrigeration system output relative to input
(F) coefficient of performance   (6) a measure of the rate of air flow in a system

#13. (4)

There are FOUR primary (and distinctly different) categories of heat sources that are normally used with building heating systems. Name these four important heat source categories:

 

# 14. (9)

Draw a schematic diagram of an absorption (chemical) refrigeration
cycle in the space adjacent. Show and label all major components and
indicate how these components are interconnected (including
direction of refrigerant flow).

Using the letters below as labels, indicate which of the components
in the sketch above perform the following functions:

(A) receives heat from a source such as a boiler, a process, or a solar collector
(B) removes heat from the refrigerant loop for disposal to the outside air
(C) removes heat from water so that building spaces can be cooled
(D) acts as a
Amagnet@ for water vapor in the refrigerant loop

 

Bonus Question 1: (3) [if you are not interested in answering this optional question or are running short on time -- just ignore it]

You have one minute to explain (to a graduate of an architecture program that has no ET support courses) what to look for when trying to determine if a particular space needs to have its own thermal control (its own zone) or not. Tell me what you'd tell them in the space below:

 

 

 

Bonus Question 2: (3) [if you are not interested in answering this optional question or are running short on time -- just ignore it]

Explain how the major functional components of a heating (or cooling) system -- namely source, distribution, and delivery -- are handled in a PASSIVE system.

 

 


Last updated 12 January 2001
http://www99.pair.com/vsfamu/et2/sampex2.htm