RCCC_CBF_-_SBF_AHU_Replacement_Electrifiction_Study.pdf

11020 Sun Center Drive , Suite 100, Rancho Cordova, CA 95670 | Office : (916) 851-3500 | www.capital-engineering.com

Rio Consumnes Corectional Center

CBF & SBF AHU Unit Replacement Electrification Study

12500 Bruceville Rd Elk Grove, CA 95757

Feasibility Narrative

March 28, 2024

Revision No. 2 - Revised: April 30, 2024

Raleigh Moyher (SacCounty) Text Box 3/4/26: Note that this report showcased a few options for the County, and the County ultimately selected option 2B (chilled and Heating hot water plant with heat recovery) for implementation in the forthcoming design.

This report provides high level background to the proposing engineers and design will be validated after contract award.

Rio Consumnes Correctional Center CBF & RBF

Unit Replacement Electrification Study i

Table of Contents Mechanical Narrative

Introduction

Existing HVAC Systems:

HVAC Equipment Replacement Design

Option 1 – Air Handling Units (AHU)- chilled water coils/gas furnace

Option 2 - HVAC System Replacement with All-Electric Systems

Mechanical System budget costing:

Electrical Narrative

Executive Summary

Project Description

Existing Electrical Service

Existing Emergency main switchboard “EMSA”

Existing 300KW Emergency Generator

Existing Emergency main switchboard “EMSB”

Existing 400KW Emergency Generator

New Work

New Panel “CH1”

New Panel “CH2”

Chiller CH-2

New Panel “HECPA”

Appendix A – Code References

Appendix B - Sketches

OPTION 1

OPTION 2A

OPTION 2B

Appendix C – Electrical Attachments

Attachment A

Attachment B

Attachment C

Attachment D ii

Attachment E

Attachment F

Attachment G

Attachment H

Appendix D - Equipment

Mechanical Narrative

Introduction

The intent of this report is to evaluate the changes required for the electrification of the rooftop Heating Ventilation and Cooling (HVAC) equipment in need of replacement at the CBF (county facility 00555) and SBF (county facility 00570) buildings at the Rio Consumnes Correctional Center (RCCC) and to eliminate all requirements for natural gas from the mentioned project reducing the carbon footprint of the site.

The information provided herewith is intended for the evaluation of the required all-electric equipment and to provide general budget pricing of such equipment.

All cost estimates within this report are rough order of magnitude budgets based on vendor feedback for the available equipment and are for reference only. Any additional detailed cost estimate for labor, markup, overhead, or other costs are provided as a typical industry standard and more detailed information should be obtained from a general contractor or estimating firm. These cost estimates are based on the date this report was issued and are subject to escalation and/or inflation at the time of purchase.

Existing HVAC Systems:

The currently installed systems consist of twenty(20) rooftop, gas furnace/ DX electric, packaged air-conditioning units serving various areas of the building.

The unit size ranges from three (3)-tons of cooling capacity DX package units to twelve and one half (12.5) tons of cooling capacity DX package units. Each of these units is equipped with a refrigerant compressor, DX coil, natural gas furnace, and economizer system. These systems are installed on a flat portion of the roof along the West side of the CBF and SBF buildings.

The units were mostly installed in the 1990s, with a few units that were replaced in the last ten years. The older units are past the end of their useful life, and in poor condition. The few newer units are in good condition and have approximately five (5) to eight (8 ) years left of their useful life expectancy if properly maintained. All these systems provide cooling via Direct refrigerant expansion (DX) and heating via natural gas furnaces.

HVAC Equipment Replacement Design

Option 1 – Air Handling Units (AHU)- chilled water coils/gas furnace.

The design for the replacement of the existing units takes into consideration the new 2022 California Mechanical Code requirements restricting the use of equipment with refrigerant systems. Per Table 1104.1 of the 2022 California

Mechanical Code, under “High Probability” refrigerant systems are not permitted to be used for an “I-3” occupancy, such as in this building (see appendix A).

Therefore, the new replacement units were selected to contain chilled water coils with gas furnaces.

The existing Air Conditioning (AC) systems are Direct Expansion (DX) and gas furnace units. The new AHUs will have a chilled water demand that can not be addressed by the current chilled water plant. To meet the cooling loads a new chiller is to be installed in the yard west of the SBF building.

The new chilled water loop will consist of a one hundred and seventy (170) nominal ton air-cooled chiller. The system will also contain two primary chilled water pumps (one + one for redundancy) three secondary chilled water pumps

(two+one for redundancy), an expansion tank, an air separator, and the typical isolation valves, accessories, and bypass configuration. This new chilled water loop will also be connected to the existing chilled water loop for Building 448 by means of a bypass as a way to provide backup chilled water to the new chilled water loop to both buildings.

The existing Dx/Furnace AC units will be replaced with similar AC units, both in cabinet size and capacity. In order to maintain a similar footprint for these units and match the supply ductwork drop and return ductwork riser, these units are of semi-custom configuration with some units requiring adaptor curbs to be installed.

With the DX coils being replaced by chilled water coils and no need for DX compressors the new units should be lighter which should not trigger any structural retrofit.

Each unit will be piped to the chilled water loop using isolation ball valves, control valves, and balancing valves with a number of these units having a three-way (3-way) control valve to allow for return water under low flow conditions.

As mentioned above, the pumping station will consist of two (2) primary loop pumps and three (3) secondary loop pumps. Both primary and secondary loops will have one pump on standby for redundancy and all the pumps will have

Variable Frequency Drives (VFD) to maintain the chilled water loop differential pressure. The pumps will be located adjacent to the chiller in the yard with piping installed on the exterior of the building and the roof.

Option 2 - HVAC System Replacement with All-Electric Systems.

Under this section, we will explore the options for an all-electric equipment system that with not use on-site generated carbon-based fuels. The replacement of the twenty existing AC units, as the option above, will eliminate the DX components to comply with the California Mechanical Code as previously noted.

In addition, these units will replace the gas furnace with heating hot water coils.

To meet the demand from these AC units chilled water and heating hot water will be required. There are a number of systems available to satisfy this need but for this study, we have narrowed down to the following options:

OPTION 2A –

AHUs with Chilled & Hot water coils – Heat Pump boiler & Air-cooled Chiller

Under this option, the chilled water system described under the current replacement project will remain, and a Heat Pump heating hot water boiler system will be installed.

The Heat Pumps, also known as hybrid boilers, can not produce the same water temperatures as a traditional boiler (Hybrid boilers produce up to approximately

140o F leaving water temperature). This will have an impact on the heating hot water coil size and potentially the AC unit size.

OPTION 2B

AHUs with Chilled and Hot water coils – 4-pipe Heat Pump System

This option will replace the chiller and boiler in Option 2A with a four-pipe Heat

Pump system that can provide both, chilled water and heating hot water at the same time. The system will be modular for future expansionability and the internal control of this system will determine the number of modules that are required to be on cooling, heating, or off depending on the demand of the buildings.

Both options 2A and 2B will be required to have a pump package for the chilled water loop and the heating hot water loop. This will include two (2) primary pumps and three (3) secondary pumps per loop with Variable Frequency Drives

(VFD), and the typical accessories such as an air separator, an expansion tank, etc.

A Water Storage or Buffer Tank for each chilled water and heating hot water loops is recommended under both options. These water tanks will be designed for depending on water usage to maitaine required minimum water temoeratures, and will be required if the total volume of the hydronic piping loop

(both, chilled water and heating hot water separately) does not have the minimum volume required by the equipment. If these Buffer tanks are installed the air separator can be incorporated with the tanks and a separate air separators for each chilled water and hot water loop will not be required.

Both piping loops will run up the side of the building and the roof to each AHU unit for both buildings.

Mechanical System budget costing:

The intent is to provide a comparison of the equipment costs associated with the requirements for providing all electric equipment to this facility. The chart below includes an order of magnitude equipment costs for the gas furnace design and the two options described above.

Additional costs such as labor and materials for the installation of the piping loops are not included above. Any contractor markups, inflation costs, or other related costs to the purchase and delivery of the equipment are also not included in this analysis.

OPTION 1

EQUIPMENT DESCRIPTION BUDGET COST

AC Units 20 units CHW/Gas ~ 150 tons @~ $3,100/ton $465,000.00 Chiller 182 tom Air colled chille $185,000.00 Pumps 5 Chilled water pumps & accessories $75,000.00 Controls New controls for Chiller and pumps TBD

OPTION 2A

EQUIPMENT DESCRIPTION BUDGET COST

AC UNits 20 semi-custom Units - CHW/HHW $550,000.00 Chiller 182-ton Air-cooled Chiller $185,000.00 Boiler Heat Pump Boiler ~4 - 30ton modules $460,000.00 Pumps 5 Chilled water pumps & accessories $75,000.00 Pumps 5 Hot water water pumps & accessories $75,000.00 Hot water loop One additional piping loop for hot water TBD Controls Added controls for boiler and HW pumps TBD

OPTION 2B

EQUIPMENT DESCRIPTION BUDGET COST

AC UNits 20 semi-custom Units - CHW/HHW $550,000.00 Heat Pump (HP) 4 pipe HP ~2,530 MBH heat/ 1,992 MBH clg. $575,000.00 Pumps 5 Chilled water pumps & accessories $75,000.00 Pumps 5 Hot water water pumps & accessories $75,000.00 Hot water loop One additional piping loop for hot water TBD Controls Added controls for boiler and HW pumps TBD

Raleigh Moyher (SacCounty) Line

Raleigh Moyher (SacCounty) Line

Raleigh Moyher (SacCounty) Callout option not selected

Electrical Narrative Electrical narrative provided by:

Stuart Lindsay, Principal of M Neils Engineering, Inc.

Executive Summary

Purpose of this Scoping Study:

The purpose of this Study is to scope/outline the existing electrical service and distribution system capacity to handle the replacement of the existing roof mounted air conditioners with a new ground mounted electric chiller for heating and cooling of Buildings 555 and 570 at the Rio Cosumnes Correctional Center

(RCCC).

The County of Sacramento should use this Scoping Study to determine the feasibility of the chiller heating and cooling electrification project.

It should be noted that the outlined Scope described in this study is somewhat rough and preliminary in nature.

Project Description

The project consists of providing the following electrical work: replace the existing roof mounted package gas-electric air conditioning units with new rooftop air handlers, and a ground-mounted electric chiller and associated pumps will be provided for heating and cooling for Buildings 555 and 570.

Existing Electrical Service:

The existing electrical service and main switchboard are located on the south side of the facility. The service voltage is 480/277V, 3-phase, 4-wire rated at 4000 amps. The 4000 amp main switchboard provides utility power to two emergency main switchboards, “EMSA” (800A, 277/480V, 3PH, 4W) and “EMSB” (800A, 277/480V, 3PH, 4W). Emergency power to “EMSA” is supplied by a 300kW, 277/480V, 3PH,4W diesel fueled generator. Emergency power to “EMSB” is supplied by a 400kW, 277/480V, 3PH,4W diesel fueled generator. Per load recordings taken over a 30-day period, the maximum electric demand on “EMSA” is 415.5 amps, and on “EMSB” is 197.9 amps. Neither “EMSA” nor “EMSB” has sufficient capacity to support the new chiller and associated circulation pumps.

Therefore, the new loads will be split between the two existing emergency main switchboards and associated emergency generators.

See Appendix C - Attachment A – Partial One-Line Power Diagram.

Existing Emergency main switchboard “EMSA”

As stated in 2.1A, existing “EMSA” is rated 800A at 277/480V, 3PH, 4W. Emergency power to “EMSA” is supplied by a 300kW (375kVA), 277/480V, 3PH,4W diesel fueled generator. “EMSA” has an existing load of 416.0 amps (345.4kVA). The existing roof mounted air conditioning units for buildings CBF and SBF will be removed. This will remove 333.25kVA of existing load. The new roof-mounted air handling units for buildings CBF and SBF along with 50% of the new chiller fan and compressors will add 367.63 amps (305.63kVA) for a total of 486.32 amps

(404.13kVA). Therefore, the existing 800 amp Emergency Main Switchboard

“MSB” will be sufficient.

See Appendix C - Attachment B – EMSA Load Calculation.

Existing 300KW Emergency Generator

As stated in 2.1A, emergency power to “EMSB” is supplied by a 300kW (375kVA), 277/480V, 3PH,4W diesel fueled generator. The existing 300kW (375kVA) generator has an existing load of 416.0 amps (345.4kVA). The existing roof mounted air conditioning units for buildings CBF and SBF will be removed. This will remove 333.25kVA of existing load. The new roof-mounted air handling units for buildings CBF and SBF along with 50% of the new chiller fan and compressors will add 367.63 amps (305.63kVA) for a total load of 382.4 amps (317.78kVA).

Therefore, the existing 300kW (375kVA) emergency generator will be sufficient.

See Appendix C - Attachment C – 300kW Emergency Generator Load Calculation.

Existing Emergency main switchboard “EMSB”

As stated in 2.1A, existing “EMSB” is rated 800A at 277/480V, 3PH, 4W. Emergency power to “EMSB” is supplied by a 400kW, 277/480V, 3PH,4W diesel fueled generator. “EMSB” has an existing load of 197.9 amps (164.5kVA). The new hot water and chilled water circulation pumps (new Panel “HECPA”) and 50% of the new chiller fan and compressors will add 327.7 amps (272.43kVA) for a total of

575.27 amps (478.05kVA). Therefore, the existing 800 amp Emergency Main

Switchboard “MSB” will be sufficient.

See Appendix C - Attachment D – EMSB Load Calculation.

Existing 400KW Emergency Generator

As stated in 2.1A, emergency power to “EMSB” is supplied by a 400kW/500kVA, 277/480V, 3PH,4W diesel fueled generator. The existing 400kW (500kVA) generator has an existing load of 197.9 amps (164.5kVA). The new hot water and chilled water circulation pumps (new Panel “HECPA”) and 50% of the new chiller fan and compressors will add 327.7 amps (272.43kVA) for a total of 525.78 amps

(436.93kVA). Therefore, the existing 400KW/500kVA emergency generator will be sufficient.

See Appendix C - Attachment E – 400KW Generator Load Calculation.

New Work

New Panel “CH1”

Provide new 42 circuit, 225 amp, 480/277V, 3-phase, 4-wire electrical circuit breaker panelboard with to feed 50% of the new chiller fans and compressors.

Provide a new 700-amp feeder (up-sized for voltage drop) to the new chiller and connect.

See Appendix C - Attachment F – New Panel “CH1” Schedule.

New Panel “CH2”

Provide new 42 circuit, 225 amp, 480/277V, 3-phase, 4-wire electrical circuit breaker panelboard with to feed 50% of the new chiller fans and compressors.

Provide a new 700-amp feeder (up-sized for voltage drop) to the new chiller and connect.

See Appendix C - Attachment G – New Panel “CH2” Schedule.

Chiller CH-2:

Furnish and install new circuits from new Panels “CH1” and “CH2” in the new chiller yard to the new chiller fans and compressors and connect.

New Panel “HECPA”:

Provide new 42 circuit, 200 amp, 480/277V, 3-phase, 4-wire electrical circuit breaker panelboard with electrical circuits to the new hot water and chilled water circulation pumps.

See Appendix C -Attachment H – New Panel “HECPA” Schedule.

Appendix A – Code References 2022 CMC Code section 1104.0 and Table 1104.1 are applicable to this project.

Appendix B - Sketches OPTION 1 – AHUs with chilled water coil and gas furnaces

Chiller plant and separate HP boiler

Line

Raleigh Moyher (SacCounty) Line

Raleigh Moyher (SacCounty)

OPTION 2A – AHU with chilled water coils and hot water coils

Chiller plant and separate HP boiler

Line

Raleigh Moyher (SacCounty) Line

Raleigh Moyher (SacCounty)

OPTION 2B – AHU with chilled water coils and hot water coils

4-pipe HP system for simultaneous chilled water and hot water production.

option selected

ATTACHMENT A

AdeBarrenaSarobe Snapshot

AdeBarrenaSarobe Text Box

Attachment B

Attachment C

Attachment D

Attachment E

Attachment F

Attachment G

Attachment H

Appendix D - Equipment All Options - Primary Pumps

All Options - Secondary Pumps

Option 1 and Option 2A – Chiller

Option 2A and Option 2B – AHU Units

Option 2A – HP Boiler

Option 2B- 4-Pipe HP Chiller/Boiler