chiller retrofit case study hertz 600 vine center

Bill Balli Donny Knight DeBra-Kuempel Chiller Group

Chiller Retrofit Case Study

HERTZ 600 VINE CENTER

2021 ICE Group Meeting

Presentation Summary

Project Background 1 Demolition, Retrofit, & Startup 4

Bidding Process 2 Energy Savings & ROI 5

Design Considerations 3 Outcomes & Learnings 6


Project Background


Hertz Investment Group @ 600 Vine Center


Hertz Investment Group @ 600 Vine Center

Project Background

Walked into conversation at shop

– How to get chillers in penthouse of high-rise?

Hertz Investment Group in downtown Cincinnati, OH

Two 800-ton Carrier 19EB Chillers

– Located on 31st floor penthouse back of building

– Maintained since install by Carrier


Bidding Process


Bidding Process

DeBra Bid

Started out leveraging Turbocor TT400

– Need six total to reach tonnage req.

Contacted SMARDT

– Inquired utilizing VTT Compressor

– Similar to a parallel job, University of Cincinnati

Quoted

– Two VTT Compressors w/remote drives

– Kiltech control panel


Bidding Process

Competition Competitive Bids

– Daikin McQuay w/four 400-ton WMCs

Complete Mechanical Changeout

– Pumps

– Chillers

– Controls

Space Limitations

Daikin contacted customer

– Warned that DeBra retrofit would not work (Due to Oil & Compressor size)


Design

Considerations


Design Considerations

Approach Philosophy

– Lots of moving parts

– KEEP IT SIMPLE

Retrofit Considerations

– Cost of Rigging

– Cost of New Chillers

– Customer ROI

– Space of Mechanical Room

– Excessive Noise/Vibration

– Minimum tonnage turndown

– Condition of Tube sheets

– Factory Economizer / Floats Vs. EXV

Two Turbocor VTT compressors w/remote drives mounted on chiller near control panel

– New control panel

– Retube Cooler & Condenser

– Factory Economizer / Floats Vs. EXV

– Installed distribution panel in replacing Wye Delta starter

Interfaces with BAS

Large Energy Savings

Thought Process Actual Build


Demolition, Retrofit,

& Startup


Two Identical Chillers in Penthouse

Chiller No. 2 (behind No.1, Remains Stock) Chiller No. 1 (Full Retrofit)


Demolition, Retrofit, & Startup

Started with:

Original Carrier 800 ton 19 EB

– 3600 lbs of R-12

– Subsequent field addition of Hot gas bypass

~35 years old



All condenser and chilled water piping to be removed

– Chiller was also going to be completely retubed

Small 3-foot walkway between Housekeeping Pad & Tower

Notice that it sat on airbags to mitigate noise/vibrations

3 Feet



Starting Point

Overhead rigging had to be fabricated.



Tear Down

View after the motor and most of the compressor has been removed



Tear Down

Everything removed



Tear Down

Oil pump was removed

Traced all oil lines out of the shell

– Some of the oil/refrigerant lines go through the uni-shell

Note:

– Still on airbags

– Original Tubes

– No economizer work yet



Tubes Removed

Added access windows

– Every condenser support sheet broke during tube removal

Dropped machine down

– Easier access to control panel

– Lowered overall height

Dropped

machine down

Added

windows



These are the holes we cut to gain access to the tube sheets.

As it turns out, the shell was one-inch thick.



Welded support sheets

These are the condenser tube sheets after they were welded in



Inside the Economizer

Keeping it simple…

Rebuilt original floats as opposed to installing electronic expansion valves

Float had worked for 35 years. Not broken – don’t fix it



Start of Fabrication

Fabricated the suction, discharge, and economizer headers

Notice that we re-welded the condenser covers



Test Fit of Compressors & Headers

Rigging used to set compressors

– Fabricated spreader bars for the compressors

Spreader Bar



Both compressors Fabbed

Note the tubes are installed and the tube sheets have been coated with Belzona



Wiring & Ancillary Piping

Electricians installing main power

– Sensor cabling

Liquid injection and economizer lines



Compressor Table

Pipefitters fabbed a plate for the compressor to sit

– Bolted the suction and discharge flange prior to drilling the compressor feet



Hot Gas Bypass

Incorporated hot gas bypass into overall controls strategy

Installed all new electronic flow switches

Removed the original DP switches – Installed thermal

displacement switches



Both economizer and liquid feed for the motor cooling were built from fabricated headers

Liquid injection header

Added Caps to shell (orig. refrig./oil circuitry through shells)

Liquid

Header

Economizer

Header



The discharge 90’s off the compressor were back-ordered

Had to set the distance of the headers which made the center-to-center on the headers off.



Close to Complete

Used Kiltech Panel

Original design had VFD’s next to Kiltech Panel to keep refrigerant piping and wiring nearby – Customer wanted drives

relocated to wall behind for spacing



Relocated the VFD’s on the wall behind the chiller instead of the original location



Finished Product



Before

After


Energy Savings &

ROI


Energy Savings & ROI

Estimating cost savings:

– Original flow meters not functioning

– Chiller No. 2 “building’s best running machine”

– Measured old Machine…

Unit Operation Design (GPM) Actual (GPM)

Condenser 2400 2897

Evaporator 1200 1837


Savings Estimate

Retrofit running at design conditions yields estimated $60k-$80k annual savings

Accounting for Condenser Relief, savings increase further

Design Carrier

(100%)

Retrofit

(100%)

Carrier

(50%)

Retrofit

(50%)

Retrofit

Condenser Relief

@ 65 degrees

Motor Amps 797 800 632 412 294 105

kW/Ton 0.7172 0.8690 0.5772 1.1745 0.4558 0.2363

Evaporator Tons 795 689 810 283 480 275


Outcomes &

Learnings


Lessons Learned – What went WRONG?

COVID-19 – Virtually all parts had extended lead-times shipping internationally

Drive Location Challenges – Customer wanted panels installed in different location than design

– Had to absorb cost of change within budget

– BE SPECIFIC. Outline all inclusion/exclusion assumptions

Every condenser tube support sheet broke – Had to cut windows for access

Underestimated spacing constraints in Penthouse – Needed to stage all equipment in lower floors – significant hours spent in the elevators


Lessons Learned – What went WELL?

Every condenser tube support sheet broke

Utilized similar job at UC for reference – Startup was extremely smooth

Performance exceeds expectations

Won maintenance contract – Previously performed by Carrier past ~35 yrs

High likelihood of second machine win – Design work can be mirrored for second machine

Thank You

chiller retrofit case study hertz 600 vine center

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