hvac due 1 hour and 30 minuets

MEEN 4200 Final Time: 2 hr Mechanical Eng., TSU Spring 2020

The underlined letters are the digits from your T#: T 0 0 A B C D E F. Please write your correct T#

on your exam. Otherwise it will not be graded!

Name: T#:

1

1. A retail store is located at Phoenix, AZ. On a typical summer day (outside air is at 10D F db and

8B F wb) with 2C people in that store. The cooling load is 1B tons. The store is kept at 72 F db

and 50% relative humidity. The cooling unit supplied air to the room at 5A F DB and 7C %

relative humidity. The floor area of the classroom is 2A00 sq ft.

a. Show all the processes on the psychrometric chart and draw a schematic of the system.

b. What is the mass flow rate of air into the space/room?

c. What is the sensible heat factor for the room

d. In order to comply with ASHRAE STD 62.1-2004, what is the minimum outdoor air required

in cfm?

e. What is the ratio of the outdoor air to the air supplied to the space?

f. What is the DB temperature and relative humidity of the air entering the AC unit?

g. When outdoor air is used, what is the cooling capacity of the AC unit in tons?

h. What is the air volume flow rate (CFM) entering the AC unit?

i. What is the apparatus dew point temperature and bypass factor for the AC unit?

j. If the maximum pressure drop is 0.3D in water across the filter, how many M100 24x24x12

filters must be used?

k. If the occupants are men and women, describe their comfort level qualitatively after 4 hrs.

2. For a given building in Louisville, KY, heating and cooling loads are AD,9B0 BTU/hr and 1C,450

BTU/hr, respectively. Assume that the system uses natural gas for heating and electricity for the

cooling. Natural gas costs about $8.B0 per 1000 cu ft. The SEER value is 1A for the unit used for

cooling. Approximately how much is the heating and cooling bills for winter and summer seasons?

Use Degree Days method.

MEEN 4200 Final Time: 2 hr Mechanical Eng., TSU Spring 2020

The underlined letters are the digits from your T#: T 0 0 A B C D E F. Please write your correct T#

on your exam. Otherwise it will not be graded!

Name: T#:

2

3. Consider the duct system layout for an office building shown below. How many tons would this

HVAC system needs to be at the least? For the HVAC system size the supply and return air

trunks, supply ducts, supply and return air registers. Label all duct sizes and registers on the

layout.

Return

Air

HVAC

Unit

CFM 1B0

CFM 1B0

CFM AD

CFM 2A0

CFM 1D0

CFM 1D0

Supply Air