HVAC System Recommendation - Lavinia Pedrollo

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Created
Jan 6, 2025 12:37 AM
Created by
Glenn Katz

To design the HVAC system for the example building, I have considered the following steps.

Step 1: In the table below, I have taken note of the reported heating and cooling loads for each space and the calculated supply airflow reported for each of the spaces included in the space schedule. (Note that not all spaces are included in the schedule).

Space Name
Cooling Load (Btu/h)
Heating Load (Btu/h)
Cooling Airflow (CFM)
Heating Airflow (CFM)
1 Office
1,994.4
489.7
69
18
2 Office
2,408.1
512.4
83
20
3 Office
1,629.5
122.8
58
16
4 Hallway / Pathway
13,282.0
1,942.1
412
373
6 Meeting Room
24,754.9
8,260.1
758
287
7 Public Space
25,372.7
8,911.8
803
310
9 Restroom
1,679.1
363.0
58
19
10 Space
6,956.8
601.0
243
27
11 Space
8,693.4
615.8
304
34
12 Restroom
1,644.3
355.7
57
19
15 Mechanical Room
1,374.8
155.0
48
20
16 Conference Room
23,099.3
7,035.0
682
245
17 Public Gathering
17,143.1
161.6
601
127
18 Cafe
44,630.1
7,318.6
1,387
306
19 Restroom
1,331.7
313.8
44
19
20 Restroom
1,298.2
205.2
45
19
21 Museum Display Room
11,224.0
676.2
397
62
22 Hallway / Pathway
4,546.6
1,819.8
134
152

Step 2: Then, I considered what the cooling and heating airflows are, highlighted in red the maximum value between the two, and estimated a reasonable (and higher) amount of airflow in CFM. This value will be used to design both the supply air diffusers and the return air diffusers.

I selected each airflow in a way that the sum is 8000 CFM, 2000CFM more than the total CFM

Space Name
Cooling Airflow (CFM)
Heating Airflow (CFM)
Selected Airflow (CFM)
1 Office
69
18
100
2 Office
83
20
100
3 Office
58
16
150
4 Hallway / Pathway
412
373
600
6 Meeting Room
758
287
900
7 Public Space
803
310
1200
9 Restroom
58
19
100
10 Space
243
27
300
11 Space
304
34
400
12 Restroom
57
19
100
15 Mechanical Room
48
20
100
16 Conference Room
682
245
700
17 Public Gathering
601
127
700
18 Cafe
1,387
306
1650
19 Restroom
44
19
100
20 Restroom
45
19
100
21 Museum Display Room
397
62
400
22 Hallway / Pathway
134
152
300

What I have noticed from this table:

  1. Unusually high heating load in Meeting Room (6):
    • The heating load in the Meeting Room is significantly higher than the other spaces, which might be unexpected. It could be due to specific activities or equipment in that room.
  2. Higher cooling airflow in the Cafe (18):
    • The cooling airflow in the Cafe is notably high compared to other spaces. This could be reasonable if there are high occupancy or heat-generating equipment in this area.
  3. Unusually low heating load in the Public Gathering space (17):
    • The heating load in the Public Gathering space is surprisingly low. This might be accurate based on the specific conditions of the space.

Step 3: given the table above, I started placing the air diffusers accordingly. Then I started modeling the air ducts, using recatngular 12x12 air ducts types. I provided two separate supply branches on each floor level, one for the West zone and one for the East zone, and I routed each supply branch back to the mechanical room on that floor level.

Step 4: I connected each duct with the air diffusers (supply and return) using flexible ducts.

Mechanical Floor Plans

Floor 0:

image

Floor 1:

image

Note: ducts and diffusers were added on floor 1 in conjunction with the stairs location, but not on floor 0 due to the actual presence of stairs at the ceiling level.

Interior Views

image
image

On of the main challenges I have encountered during the HVAC layouting was ensuring that the ducts did not obstruct critical areas like elevators and stairs. I accidentally covered the stairs on the floor zero and I had to rework in a later stage to remove the ducts and air suppliers from there.

Additionally, I have noticed that there any conflicts between my structural system and my mechanical systems, like shown in the image below.

image

Also, supply duct routing was challenging in terms of understanding where to place the airflows correctly so that to avoid the intersection of air ducts for return and supply air.

Finally, I would place a ceiling to conceal the structural and mechanical systems right below the lowest element (in my case, the return air ducts), at a heights of 8’ (at level of the air diffusers). This ensures that the design not only enhances the visual appeal but also maintains optimal functionality, as 8’ is a good height for a small building like the one of this assignment.