Attachment 7 - SEP 2023 Chilled Water System Analysis Report.pdf

Chilled Water System Analysis Miami VA Medical Center

Miami, Florida

Contract 36C24819D0021, 36C24823N0259 Project 546-23-105

DRAFT REPORT

Prepared for

Department of Veterans Affairs Bruce W. Carter VA Medical Center

Engineering Service, Room B110

Planning and Analysis

1201 NW 16th Street

Miami, FL 33125

Prepared by

3603 NW 98th Street, Suite B

Gainesville, Florida 32606

September 18, 2023

Design, Inc.

Create Redundancy Capacity in Chiller Plant System/ DRAFT Chilled Water Analysis Report Chilled and Condensed Water System Repair/Replacement Bruce W. Carter VA Medical Center, Miami, FL

Contract 36C24819D0021, 36C24823N0259, Project 546-23-105

AKEA Design, Inc. Page 1

Table of Contents

Executive Summary

Existing Data

Miami VAMC – Control System

Cooling Tower System

Chilled Water System

Campus Chilled Water Loads

Chiller Plant Load Capacity

Cooling Tower Water and Chilled

Water Capacity Analysis

Mechanical - Observations

Mechanical - Summary and

Recommendations

Electrical Load Calculations -

Normal

Clarifications

AKEA Design, Inc. Page 2

EXECUTIVE SUMMARY ANALYSIS SCOPE & PURPOSE

This is an engineering Comprehensive Campus-Wide Chilled Water System Analysis for the existing chilled water system distribution including the facility and future expansion on the entire

Bruce W. Carter Veterans’ Hospital (BWCVAH) campus.

The analysis includes all the existing chilled water systems housed in the BWCVAH’s CEP -

Building 44. The central chilled water distributing equipment consists of Cooling Towers, Cooling Tower Pumps, Chillers, Primary Chilled Water Pump and loop, and Secondary Chilled

Water Pump and loop distributing chilled water to the entire hospital campus through dedicated

Tertiary Pump Loops to the following buildings:

• Building 1 – Main Hospital Building

• Building 7 – Research & Education

• Building 10 – CLC (Community Living Center)

This Comprehensive Campus-Wide Chilled Water System Analysis will be expected to be used as a BWCVAH Master Plan and included as an expansion project analysis, according to the project’s scope of work (SOW). The BWCVAH Campus’ Master Plan is in process and actual construction is expected to be completed within a period of 5 years. It will require a chiller system to distribute the tonnage/chilled water flow capacity and the required sustainability.

The purpose of this analysis is to provide a comprehensive analysis of the design/actual chilled water distribution system systems. This analysis will also provide a recommended approach to meet this design, current, and future cooling demands.

AKEA Design, Inc. Page 3

EXISTING DATA

Existing Chilled Water System Overview

The Bruce W. Carter Veterans’ Hospital’s CEP (Central Energy Plant) is in Building 44. This building houses the Main Control Room, all central chilled water system distributing equipment consisting of Cooling Towers (2 ea.), Cooling Tower Pumps Loop (4 ea.), Chillers (3 ea.), Primary Pumps Loop (4 ea.), and a Secondary Pumps Loop (12 ea.) distributing chilled water to the entire hospital campus through Tertiary Pump Loops in the following buildings:

• Building 1 – Main Hospital Building

• Building 7 – Research & Education

• Building 10 – CLC (Community Living Center)

This analysis’s survey data collection was conducted by AKEA Design, beginning with a visit to the CEP Building 44, from March 21, 2023, to September 7, 2023. The latest data gathering necessary to develop this chilled water demand assessment was provided by email on September

8, 2023, by the VA.

AKEA Design, Inc. Page 4

MIAMI VAMC - CONTROL SYSTEM

Controls are managed through the campus Building Automation System (BAS), Siemens.

Figure 1. CEP’s Control Room - Primary Chilled Water System Screen

Figure 2. CEP’s Control Room – Primary Chilled Water System Trend (8/16/23) Screen

AKEA Design, Inc. Page 5

Figure 3. CEP’s Control Room – Secondary Chilled Water System Trend (8/24/23) Screen

AKEA Design, Inc. Page 6

COOLING TOWERS SYSTEM

CEP Building 44’s two (2) existing Cooling Towers (Table 1), for the chillers’ condenser water needs, are located adjacent to this building on the yard... The existing Cooling Tower Pumps

(Table 1A and 1B) are housed in the CEP Building 44 as well.

Table 1A. Design/Actual/Cooling Tower System

(Existing 4-Cells Cooling Tower Running/Existing 2-Cells Cooling Tower Standby)

(Existing Two Cooling Tower Pumps Running/Existing Two Cooling Tower Pumps Standby)

Cooling Tower

No.

Cooling Tower

Pump No.

Cooling

Tower

Tonnage

(Tons)

CT Pump

Flow

(gpm)

11-2-CWP-1 3750 On

11-2-CWP-2 0 Stadnby

11-2-CWP-3 0 3750 On

11-2-CWP-4 0 0 Standby

Totals 2200 7500

Notes:

1-11-CT2 (2-Cells)

1-11-CT1 (4-Cells) 2200

Cooling Towers / Pumps - Tonnage/Flow (gpm)

Equipment Connected Loads

Duty

(On/Standby)

1. Cooling Towers Water flow capacity: 3 gpm per Ton

3. Cooling Tower Pumps 11-2-CWP-1 and 2 running. Cooling Tower Pumps

11-2-CWP -3 and 4, redundancies, respectively.

2.The actual 4-cells cooling tower of 2,200 tons does not match with the actual two chillers in service, 2,500 tons (1,250 tons per chiller).

AKEA Design, Inc. Page 7

Table 1B. Proposed Cooling Tower System

(Existing 4-Cells Cooling Tower Running/Existing 2-Cells Cooling Tower Running /New 2-

Cells Cooling Tower Standby)

(Existing Three Cooling Tower Pumps Running/One Existing Cooling Tower Pumps Standby)

AKEA Design, Inc. Page 8

CHILLED WATER SYSTEM

The existing chillers housed in CEP Building 44, shown on Table 2, were originally designed to supply chilled water at 42 degrees F with a temperature rise of 10 degrees F.

The chilled water system loops’ flow and pressure (TDH) conditions of the primary and secondary pumping loop systems are shown in Table 2A and 2B.

Table 2A. Design Chilled Water System

(Existing Two Chillers Running/Existing One Chiller Standby)

(Existing Two Primary Pumps/Running/Existing Two Primary Pumps Standby)

Chiller No. Primary Pumps Tonnage

(Tons)

Design

Flow

(gpm)

11-2-CHIL1 11-2-CHWP-1 1250 3000.00 On

11-2-CHIL2 11-2-CHWP-2 1250 3000.00 On

11-2-CHIL3 11-2-CHWP-3 0 0.00 Standby

11-2-CHWP-4 0 0.00 Standby

Totals 2500 6000.00

Notes:

Chiller Tonnage/Flow (gpm)

Equipment Connected Loads

Duty

(On/Standby)

2. Design Chilled Water temperature Rise (Original) : = 10 deg. F

3. Chiller 11-2-CHIL3 and Primary Pump 11-2-CHWP-4 are redundancies, respectivellly.

1. Chilled Water Leaving Temperature = 42 deg. F

AKEA Design, Inc. Page 9

Table 2B. Proposed Chilled Water System

(Existing Three Chillers Running / New Chiller Standby)

(Existing Three Primary Pumps Running/Existing One Primary Pumps Standby)

AKEA Design, Inc. Page 10

CAMPUS CHILLED WATER LOADS

AKEA Design Inc. summarized the campus buildings’ chilled water consumption loads based on data provided by the VA.

The actual secondary piping loop system distributes chilled water to the entire hospital campus, from CEP Building 44 through secondary pumps, supplying the demanded design tonnage and the chilled water flow as shown on Table 3A, resulting in a campus actual tonnage/flow demand of 4,024.17 tons and 9,658 gpm of chilled water, respectively.

The design secondary pumps system is depicted in Table 3B for comparison purposes.

Table 3A. Actual Buildings’ Chilled Water Consumptions

Buiding No. Building Description Design Demand

Tonnage (gpm)

Design Demand Flow

(gpm)

Buiding 1 Main Hospital 3333.33 8000.00

BUILDING 7 Research & Education 396.67 952.00

BUILDING 10 CLC (Community Living Center)

294.17 706.00

4024.17

9658.00

References:

1. E: 546-23-105 Miami Chiller Redundancy Progress Meeting with Contracting Followup; on

September 8, 2023.

2. Formula: Chiller Ton = GPM x ΔT / 24.

Buildings Load Sumary

Design Demand Flow (gpm)- Grand Total

Design Demand Tonnage (Tons)

AKEA Design, Inc. Page 11

Table 3B. Design Buildings’ Chilled Water Consumption

Buiding No. / Zone Name Building/Zone Description Secondary Pumps Duty (On/Standby) Design Demand

Tonnage (gpm)

Design Demand Flow

(gpm)

OR AND SICU 11-2-CHWP 7A On 93.75 225.00

11-2-CHWP 7B Standby

MEA-42 and 1-1-AH22 11-2-CHWP 5A On 535.42 1285.00

11-2-CHWP 5B Standby

Penthouse 11-2-CHWP 6A On 614.58 1475.00

11-2-CHWP 6B Standby

Ambulatory Care 11-2-CHWP 8A On 458.33 1100.00

11-2-CHWP 8B Standby

MEA-28 11-2-CHWP 9A On 770.83 1850.00

11-2-CHWP 9B Standby

Nursing Home 11-2-CHWP 10A On 791.67 1900.00

11-2-CHWP 10B Standby

3264.58

7835.00

References:

2. Refererence information:: OPERATIONS AND MAINTENANCE MANUAL, THE UTILITY PLANT AND ELECTRICAL DISTRIBUTION SYSTEM, VAMC MIAMI, FLORIDA, JANUARY

31, 2008, FINAL SUBMISSION

3.. Formula: Chiller Ton = GPM x ΔT / 24.

Buildings Load Sumary

Design Demand Flow (gpm)- Grand Total

Design Demand Tonnage (Tons)

1. Refererence information:: Drawing M701G - Chilled Water and Condenser Flow Diagram Area G, Utility Plant, November 3, 2003.

AKEA Design, Inc. Page 12

CHILLER PLANT LOAD CAPACITY

Table 4A. Actual Chiller Plant Load Summary

(Existing Two Chillers Running/Existing One Chiller Standby)

Item Description Tonnage

(Tons)

Chilled water

Flow

Assesment

(gpm)

Actual two (2 ea.) Running Chillers / Primary Pumps Supply 2500.00 6000.00

Users Consumption 4024.17 9658.00

Available Capacity (Surplus/Defficit) -1524.17 -3658.00

Consumption Capacity Percentage 160.97% 160.97%

Available Capacity Percentage -60.97% -60.97%

Consumption Capacity 603.63 1448.70

Consumption Capacity Percentage 15.00% 15.00%

Users Consumption 4627.79 11106.70

Available Capacity (Surplus/Deficit) -2127.79 -5106.70

Consumption Capacity Percentage 185.11% 185.11%

Available CapacityPercentage -85.11% -85.11%

Chiller Plant Load Capacity (Full Blast)

Design

Design / Actual Load Capacity

Future Load Capacity

Design /Actual/Future Load Capacity

AKEA Design, Inc. Page 13

Table 4B. Proposed Chiller Plant Load Summary

(Three Existing Chillers Running /New Chiller Standby/Three Existing Primary Pumps

Running/One Existing Primary Pump Standby)

AKEA Design, Inc. Page 14

COOLING TOWER WATER AND CHILLED WATER CAPACITY

ANALYSIS

The original design and actual capacities provided from Bruce W. Carter Veterans’ Hospital’s

Central Energy Plant (CEP) are the following:

✓ Chillers o Total Actual Design Tonnage = 2,500 (Table 2A):

▪ Two Chillers/Cells Cooling Tower Running – 2500 tons (1250 tons each)

▪ One Chiller/2-Cell Cooling Tower Standby - 1250 tons o Current Total Actual Operational Tonnage = 3,750 (Table 2B):

▪ Three Chillers/Cells Cooling Tower Running – 3750 tons (1250 tons each) o Current Total Proposed Design Tonnage = 3,750 tons. (Table 2B):

▪ Three Chillers Running/Cells All Cooling Tower Running – 3,750 tons

(1250 tons each)

▪ New Chiller Standby

No Cooling Tower Standby

✓ Entire Campus Chilled Water Tonnage/Flow Demand (Tables 3A, 4A, and 4B) o Actual demand is 4,024.17 tons or 9,658 gpm o Future demand is 603 tons or 1,448.70 gpm (estimated)

▪ 15% of the actual demand (estimated) o Actual/Future Chilled Water demand is 4627.79 tons or 11,106.70 gpm

✓ At the Actual Campus Chilled Water demand the cooling tower water for required condensation demand will be as follow:

o Cooling tower water requirement - 12,072.51 (4,024.17 tons multiply by 3 gpm/ton} o Two existing cooling towers/three existing cooling tower pumps running supply

11,250 gpm, resulting in 822.51 gpm slightly marginal/short.

o A new 3,250 gpm (1,250 tons) standby cooling tower shall be provided. The cooling tower system redundancy.

o At this scenario, the cooling tower system can satisfy the estimated additional

15% of Future Demand Load.

o (Refer to Table 1A and/1B).

AKEA Design, Inc. Page 15

MECHANICAL - OBSERVATIONS

▪ The CEP’s Chillers Plant is running over its full capacity, with no redundancies in place.

This additional load is about 61%.

o Per the Design/Actual Load Capacity Evaluation, as shown on Table 4A, Miami

VAMC’s design tonnage (tons) demand is 160.97% (Consumption Capacity

Percentage). It is more than 100% of the Total Design Tonnage, with a deficit of

1,524.17 tons or 3,658 gpm.

o At actual conditions, the chilled water flow demand is 160.97%. This is 60.97% over the actual chiller plant capacity.

▪ The Actual Primary Loop Total Chilled Water Flow [4,024.17 tons or 9,658 gpm] is greater than the Design Secondary Loop Water Flow [3,264.58 tons or 7,835 gpm]. (See

Table 3A and 3B):

o This results in 759.59 tons or 1,823 gpm more than the Designed Primary Loop

Chilled Water tonnage/flow that can be handled across the chillers in case all the secondary loop total flow capacity is demanded by the building.

▪ This indicates that the chillers in any condition, design or actual, have their capacities greatly compromised when peak load is requested at the actual conditions.

▪ Miami VAMC estimated Future Load Capacity consumption to be the following (See

Tables 4A, and 4B):

o Approximately 16% of tonnage/flow capacities.

o Approximately 600 tons or 1,449 gpm.

▪ At Existing Actual Load Capacity consumption, three (existing) chillers/all existing cooling towers running (See Table 4B):

o The expected tonnage consumption will be 107.31% (7.31% over actual consumption), a deficit of 274.17 tons.

o The expected design chilled water demand will be 107.31 % (7.31% over actual consumption), a deficit of 658.00 gpm of chilled water flow.

o The expected design cooling tower water demand will be 107.31 % (7.31% over actual consumption), a deficit of 822.51 cooling tower flow.

o No system redundancy is in the actual scenario.

▪ Per HVAC Design Manual, 2021, Rev. March 1, 2022, on section 4.5.2 LIMITING PIPE

SIZING PARAMETERS

o Maximum Fluid Velocity for Chilled Water piping above 2 in. [50 mm] is 10.0 feet per second (fps) [3.0 m/s] o At Maximum Pressure, the drop is 4.0 ft WG (water gauge)/100 ft [0.4 kPa/m]

AKEA Design, Inc. Page 16

Chilled Water Loops (Primary and Secondary o At new normal conditions, the flow in 24” pipe diameter in the primary loops of

12,000 gpm, the flow velocity is 9.58 fps. OK.

o At new normal conditions, the chilled water demand flows in a 24” pipe diameter secondary main loop of 9,658 gpm, the flow velocity is 7.71 fps. OK.

o At new normal and future conditions, the chilled water demand flows in a 24” pipe diameter secondary main loop of 11,106.70 gpm, the flow velocity is 8.86 fps. OK.

Cooling Tower Loop o At new normal conditions, the flow in 24” pipe diameter in the cooling tower loop of 15,000 gpm, the flow velocity is 11.92 fps.

▪ Note: 1.92 ft/sec above the VA standard requirement.

AKEA Design, Inc. Page 17

MECHANICAL - SUMMARY AND RECOMMENDATIONS

1. Miami VAMC is running the CEP system tonnage at full capacity with no redundancy available.

a. Miami VAMC is running at its CEP Building 44 available chilled water capacity:

two (2) 1,250 tons each chiller and onsite three (3) air cooled temporary chillers to satisfy the campus actual chilled water demand.

b. There is no actual redundancy.

c. The existing Chiller No. 3 is out of service.

2. The actual 4-cells cooling tower of 2,200 tons does not match with the actual two chillers in service, 2,500 tons (1,250 tons per chiller).

3. With any chillers shut down for maintenance or for any damage, Miami VAMC will be in an exceedingly difficult situation to operate the whole campus from CEP.

4. The existing chilled water Primary and Secondary loops are sized per the VA

Standard hydronic piping sizing criteria.

5. It is recommended to add the following items to satisfy the actual chilled water and cooling tower water campus demand:

a. It is suggested to provide a new one 1,250 tons chiller and 2-cells cooling tower, to meet the actual and the future Miami VAMC Campus’ demand loads.

b. This new chiller and cooling tower as mentioned above, with its respective will provide the necessary actual chilled water system’s pick load and the redundancy to Miami VAMC Campus.

c. As long as Miami VAMC isolate the Buildings 7 and 10 from the Chilled Water loop, this modification will leave approximately 690.84 tons (1,658 gpm). (See tables 3A, 4A, and 4B).

d. Per the above modification the CEP Chilled Water loop will supply 3,300 tons

(8000 gpm). (See tables 3A, 4A, and 4B).

e. The expected surplus of chilled water demand when Buildings 7 and 10 are isolated from the CEP Chilled water loop will be approximately 690.84 tons

(1,658 gpm) freed by those buildings. (See tables 3A, 4A, and 4B).

f. It is recommended that the above-mentioned new items’ installation be performed during the cold weather season (November through February).

6. It is recommended to perform a whole Miami VAMC Campus Chilled Water

Analysis building by building and room by room to have a real, whole Miami VAMC

Campus’ chilled water demand consumption.

AKEA Design, Inc. Page 18

7. A third-party TAB (Test, Adjust, & Balance) report is suggested to be performed for the whole Miami VAMC Campus in order to validate the design and actual conditions as shown in this report.

a. It is recommended to perform the TAB report during the hot weather seasons

(from May through August), to have a true sample and to confirm that the design conditions are met.

AKEA Design, Inc. Page 19

ELECTRICAL LOAD CALCULATIONS - NORMAL

There are currently 6 substations feeding the loads at the VA hospital Miami. Substations 3UPA, 3UPB, 3UPC, 3UPD, 3UPE and 3UPF primary side are fed from Florida Power and Light via medium voltage wire. The emergency supply is provided by SB-3UP, powered by three Caterpillar generators on the 4th floor, 2145kW each. The normal load calculations and the spare capacity for the substations are shown below.

ELECTRICAL LOAD CALCS (DATE: 9/15/2023)

POWER

SOURCE

CAPACITY IN

AMPS (TRIP)

DEMAND IN

AMPS NEW SPARE CAPACITY

SUB 3UPA 2000 1113 887

SUB 3UPB 2000 1300 700

SUB 3UPC 2000 447 1553

SUB 3UPD 2000 856 1144

SUB 3UPE 2000 621 1379

SUB 3UPF 2000 716 1284

ELECTRICAL LOAD CALCULATIONS - EMERGENCY

The emergency switchgear that is being fed from the 3 caterpillar generators is feeding 9 loads which includes the 6 substations in it. This switchgear has an estimated load of 6660 A. This estimate is based on the load of the 6 substations it is feeding. The exact demand on the 3 CAT generators and the 3 Detroit Generators will be determined by AKEA Design in the next visit.

AKEA Design, Inc. Page 20

CLARIFICATIONS

1. This analysis is exclusively dedicated to the VA Miami CEP Building 44’s mechanical and electrical conditions.

2. Not included in this report:

a. Energy saving evaluations.

b. Salvage equipment evaluations

c. Construction cost estimate