Scenario
The task is to calculate the heat gain in a café in a commercial building in Al Ain. Design a summer air conditioning system that utilizes minimum power. The following information has been provided:
· The place is a café in a commercial building in RAK.
· The calculation on the basis of 21st of July.
· The air inside the room is to be 22 ℃ (DBT) and 55 % RH.
· Outdoor air condition: 45 ℃ and 55% RH.
· Maximum outdoor temperature: 45℃; daily range: 13℃.
· Time when the cooling loads are evaluated: 3:00 pm.
· The café is open from 8:00 am to 11:00 pm.
· There are on average 15 customers and 5 staff in the café.
· The café is 25 m long, 20 m wide and 4.0 m high
· The North-West wall is sunlit. This wall has 1 glass windows 20mx3.0 m. Consider all other walls as next to other rooms with the same temperature so not heat is conducted.
· The café must have maximum sunlight and equipped with two coffee machines.
Note: Assume a sensible wall material with finish and air film. Also, assume any missing data with justification.
Task 1:
Determine for the given space:
a. The sensible cooling load
b. The latent cooling load
Task 2:
Draw the layout of the air conditioning system and analyze the airconditioning processes using psychrometric chart. You can assume the missing data.
Task 3:
Draw the duct layout and sizing the duct system using the Equal Friction Method
Task 1
1. Drawing: (10 Marks)
Plan view, elevation view, and 3 D view using solid work
Show the dimensions and number of windows, number of doors on the drawing.
2. Location: (1 Marks)
Building location, orientation and external shading
3. Outdoor design conditions: (2 Marks)
Obtain the outdoor weather data for the building location and select the outdoor design conditions.
4. Indoor design conditions: (2 Marks)
Specify temperature, humidity, air velocity
5. Operating schedules: (2 Marks)
Obtain a schedule of lighting, occupancy, internal equipment, appliances and processes generating heat load
6. Date and time: (2 Marks)
Select the time and month to estimate the cooling load.
7. Heat gain through the sunlit wall and three shaded walls. Solar radiations: (10 Marks)
8. Heat gain from Windows: (10 Marks)
9. Infilteration and Ventilation (10 Marks)
10. Heat gain from Lights: (4 Marks)
11. Heat gain from occupants: (5 Marks)
12. Total of internal and external load and Ton of A/C required: (4 Marks)
Task 2
1. Draw the Process on the Psychrometric Chart (5 Marks)
2. Analyze the problem on a psychrometric chart and determine the following: (15 Marks)
a. Sensible heat factor
b. The room apparatus dew point
c. The temperature of the air leaving the coil
d. Total air quantity required
e. Percentages of fresh air return air
f. The temperature of mixed air entering the coil
g. Coil apparatus dew point
h. Moisture removal
Task 3
1. Draw the layout of the duct design- Line diagram (5 Marks)
2. Using the Equal Friction Method, determine: (15 Marks)
A. the diameters of the ducts
B. the total pressure loss of each run of ducts
C. the amount of damping required
