17-Basis of Design PNC2132023C1.pdf
PDF 118 KB Posted
- Solicitation number
- PNC2132023C1
- Issued by
- Broward County, Fort Lauderdale City, Florida
About this file
This is a Basis of Design document prepared for the Broward County Health Department Clinic HVAC and BAS Replacement project located at 2421 SW 6th Avenue, Fort Lauderdale, Florida. The project encompasses approximately 35,878 gross square feet of commercial space comprising a health clinic and office space. The scope includes complete replacement of the building's heating, ventilation, and air conditioning systems, as well as the building automation system (BAS). The primary work involves installing two 132-ton air-cooled chillers (one operating, one standby) with variable-flow chilled water pumps to replace an existing 130-ton chiller. The first floor will be upgraded from six constant-volume chilled water air handling units (AHUs) with hot water heating coils to variable-air-volume (VAV) chilled water AHUs with electric reheat coils. The second floor will similarly be converted from existing VAV units with hot water reheat to new VAV units with electric reheat. Additional upgrades include replacement of an existing CRAC unit in the IT room with a dual-source unit (chilled water plus direct expansion), installation of a new chilled water AHU for the TB area, partition wall extensions to separate return air plenums by zone, replacement of all flexible ducts, volume dampers, and fire dampers, and complete replacement of the BAS with a new BACnet-based system. The design maintains indoor conditions of 72°F and 55% relative humidity for general areas, with the pharmacy designed for 68°F and 50-55% relative humidity.
The system design complies with ASHRAE 90.1 2022 requirements and the Florida Building Code 2023, 8th Edition, with outside air calculations following FBC commercial requirements and AHCA guidelines for healthcare facilities. The HVAC envelope design incorporates wall assembly with an R-value of 4.1 (hr·ft²·F)/BTU, roof insulation with an R-value of 11.4 (hr·ft²·F)/BTU, and windows with a U-value of 1.04 BTU/(hr·ft²·F) and solar heat gain coefficient of 0.66. Heating will be provided by electric heaters in VAV boxes, eliminating the existing boiler system and associated hot water pumps. Cooling will be delivered through the air-cooled chiller and AHUs. All equipment will be selected for the lowest feasible sound levels with additional noise attenuation measures considered where necessary. The project is funded by Broward County and is subject to County/State license requirements, bonding requirements, and mandatory site visits. The document was prepared by Jose Felipe, Mechanical Engineer at Delta G Engineers, on behalf of Broward County.
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Text version
Basis of Design / Description of HVAC System
Project Name: Broward County Health Department Clinic
Address: 2421 SW 6th Ave, Fort Lauderdale, FL, 33315.
Client: Broward County
Team developing the document:
Mechanical Engineer: Jose Felipe Company: Delta G Engineers
Project Description:
The project consists of approximately (35,878 GSF) of (commercial space). The (Broward County Health Department Clinic – HVAC and BAS Replacement) site is located at (2421 SW 6th Ave, Fort Lauderdale, FL – 33315). The site interior area primary function consists of (a health clinic and office space), while the site outdoor area function contains (a parking lot on grade).
This document captures the project factors that contribute to decisions about HVAC systems.
1. Envelope Design
1.1 Opaque wall assembly with all R-values:
Rwall=4.1 (hr*ft²*°F)/BTU Rroof= 11.4 (hr*ft²*°F)/BTU
1.2 Window performance – U-value, glazing, solar heat gain coefficient (SHGC):
Uv: 1.04 BTU/(hr*ft²*°F)
SHGC: 0.66
SC: 0.76
2. HVAC System
The section is completed by Jose Felipe, Mechanical Engineer at Delta G Engineers.
2.1 Narrative Description of System
The project consists of replacing the existing building air conditioning and ventilation systems.
The cooling system will be provided by an air-cooled chiller, with a second chiller serving as a 100% backup. Two variable-flow chilled water pumps will be installed, one operating and one in standby.
On the first floor, there are currently six constant-volume chilled water air handling units (AHUs) with hot water heating coils supplied by a boiler. These units will be replaced with variable-air-volume (VAV) chilled water AHUs and VAV terminal boxes with electric reheat coils, allowing for improved zone-level temperature and humidity control. In addition, partition walls will be extended to the slab above, dividing the return air plenums by zone to prevent air mixing and ensure better environmental control.
A new chilled water AHU will be added to serve the TB area, replacing the existing DX AHU located on the second floor.
Where possible, existing air ducts will be reused; however, in many areas new ductwork will be installed.
The existing CRAC unit serving the IT room will be replaced with a dual-source unit (chilled water + DX), providing redundancy within the same system.
On the second floor, there are two variable-air-volume chilled water AHUs with VAV boxes equipped with hot water reheat.
These will be replaced with new variable-air-volume chilled water AHUs and VAV boxes with electric reheat. In addition, the existing DX AHU serving the office area will be replaced with a chilled water AHU. Partition walls will also be extended to the slab above to separate return air plenums by zone.
Since humidity and heating control will be managed through electric reheat in the VAV boxes, the boiler system and associated hot water pumps will be eliminated.
All new equipment will comply with the minimum efficiency requirements of the Florida Building Code (FBC) 2023, 8th Edition.
Outside air calculations will follow the FBC commercial requirements as well as AHCA guidelines for healthcare facilities, ensuring proper indoor air quality.
Fans will be replaced as required to meet the new CFM values determined in the updated calculations.
All equipment will be selected for the lowest feasible sound levels, and additional noise attenuation measures will be considered where necessary.
The building automation system (BAS) will be completely replaced with a new BACnet-based system, designed in accordance with Broward County standards.
Load calculations will be performed to maintain indoor conditions of 72°F and 55% RH for all rooms, except for the pharmacy, which will be designed for 68°F and 50–55% RH.
All flexible ducts, volume dampers, and fire dampers will be replaced with new components.
The scope of work for this project consists of replacing the existing air conditioning and ventilation units, as well as the associated ductwork required to ensure proper temperature and humidity control throughout the building.
The following equipment is being replaced with new:
1) Existing 130 ton air-cooled chiller with new (2) 132 ton air-cooled chillers (one operating and one in stand by)
2) Existing 7 ton chilled water and constant flow AHU-1 with new 7 ton chilled water and VAV flow AHU-1-1.
3) Existing 6 ton chilled water and constant flow AHU-2 with new 5 ton chilled water and VAV flow AHU-1-2.
4) Existing 4 ton chilled water and constant flow AHU-3 with new 12 ton chilled water and VAV flow AHU-1-3.
5) Existing 14 ton chilled water and constant flow AHU-4 with new 13 ton chilled water and VAV flow AHU-1-4.
6) Existing 10 ton chilled water and constant flow AHU-5 with new 9.5 ton chilled water and VAV flow AHU-1-5.
7) Existing 7 ton chilled water and constant flow AHU-6 with new 6.5 ton chilled water and VAV flow AHU-1-6.
8) Existing 38 ton chilled water and VAV flow AHU-2.1 with new 31 ton chilled water and VAV flow AHU-2-1.
9) Existing 28 ton chilled water and VAV flow AHU-2.2 with new 21 ton chilled water and VAV flow AHU-2-2.
10) Existing 5 ton DX and constant flow AHU-EX-1 with new 11 ton chilled water and VAV flow AHU-1-7 (DOAS).
11) Existing 5 ton DX and constant flow FCU-1 with new 4 ton chilled water and VAV flow AHU-2-3.
12) Existing DX CRAC-UNIT for IT Room with new (Chilled water+DX) CRAC-AHU.
1)The system design meets the ASHRAE 90.1 2022 requirements.
2) Heating system – Electric heaters.
3) Cooling system- Air-cooled chiller and AHU’s.
4) Ventilation- Motorized outside air damper.
System selection by space:
Space Heating System Cooling System Air Handling Additional
Ventilation (if any)
Other
1st Floor Electric Heaters Chilled Water AHU-1-1 to AHU-1-7 Code Minimum
2nd Floor Electric Heaters Chilled Water AHU-2-1 to AHU-2-3 Code Minimum
Space Name or Type (from owner’s project requirements)
Pharmacy
Other areas
Load Assumptions
Density (ft2 per person) By Code By Code
Sensible (Btu/h per person) 245 245
Latent (Btu/h per person) 205 205
Equipment density BTU/HR
300/Compt. 300/Compt.
Envelope components winter loss(BTU/hr.)
Calculated by software
Calculated by software
Envelope components summer gain (BTU/hr.)
Calculated by software
Calculated by software
Indoor Environmental Design Conditions
Heating
Dry-bulb temperature
Cooling
Dry-bulb temperature
68 72
Relative humidity 50-55 55
Maximum air velocity FPM 45 45
Noise criteria NC<35 NC<35
Air Quality:
Ventilation cfm/ft2 Per FBC (M) Table
403.3 and AHCA requirements
Per FBC (M) Table
403.3 and AHCA requirements
Outdoor Air (cfm per person) Per FBC (M) Table
403.3 and AHCA requirements
Per FBC (M) Table
403.3 and AHCA requirements
Air changes per hour Calcs are based on table 403.3
Calcs are based on table 403.3
Filtration efficiency per ASHRAE
MERV-13 MERV-13
2.2 Load Calculations
A. Occupancy in each space:
a. Space 1- 1st floor- By Arch.
b. Space 2- 2nd Floor- By Arch
B. Load calculation method/software: Carrier EII.
C. Weather file: Fort Lauderdale, FL.
D. Summer outdoor design conditions: [91] °F drybulb, [79] °F wetbulb
E. Winter outdoor design conditions: [46] °F drybulb
F. Indoor design conditions: [72] °F, [55] % RH cooling; [72] °F heating
G. Minimum temperature during unoccupied mode: [75] °F db
H. Internal heat gain assumptions:
People, Lighting, Computers, Office Equipment.
I. Cooling load assumption:
None.
J. Other load calculation assumptions:
None.
K. Part load performance strategies
CO2 monitoring/controls and compression staging + interior compressors on VRF units.
2.3 Reasons for System Selection
One for one replacement.
2.4 Sequence of Operations
Refer to controls on sheet M-4.0.
2.5 Outside Air Supply
O/A is controlled by modulating dampers according to CO2 levels.
File details come from the government source that posted it. Updated .