Air-Cooled Chillers Efficiency, Affordability and Life Cycle

Cost Advantages for Healthcare

Air-Cooled Chillers Efficiency, Affordability and Life Cycle Cost Advantages for Healthcare

“This isn't your Father’s

air-cooled chiller”

Presented by: David N. Schurk DES., CEM., LEED-AP., CDSM., CWEP., SFP., CIAQM., HCCC., National Healthcare Strategic Account Manager, Carrier Corporation

Air-Cooled Chillers Heating/Piping/Air-Conditioning

Engineering Magazine May, 2014 (with 2017 update)

100,000 ft(2) 385-Tons

Air-Cooled Chillers What's Changed?

Chillers Full Load IPLV Improvements

Past 9.75EER 1.23kW/Ton

12.24EER 0.98kW/Ton

+13% Full Load

Todays A/C Chillers

+11 EER 1.09kW/Ton

+21 EER 0.57kW/Ton

+42% Part Load

1970 Z-28 Camaro 2018 Dodge Challenger SRT

“More miles

per-gallon ”

Air-Cooled Chillers What's Changed?

Air-Cooled Chillers

Compression Technology

Screw Compressor Reciprocating Compressor

What's Changed?

“Leaner & meaner

engine”

Scroll Compressor

Air-Cooled Chillers

Compressor VFD Fan VFD

What's Changed?

Air-Cooled Chillers

Low-Noise Aeroacoustic Condenser Fan Traditional Condenser Fan

What's Changed?

Aerodynamics Technology

Same air flow through condenser coils at 25% lower speed 850 vs. 1140 rpm

Slower speed means better reliability Increased motor and bearing life

Cycle time (25% less) Bearing Loads (45% less)

.75 3 = 42%hp

“Its all about the clean lines”

Air-Cooled Chillers

Heat Exchange Technology

Microchannel Copper Tube/Alum Fin

What's Changed?

“More bang for the buck”

Air-Cooled Chillers

Refrigerant Economizer

What's Changed? “Turbo-charged

Compression”

Air-Cooled Chillers

BAS Interface & Energy Management

What's Changed?

“Easier- handling around

the curves”

Air-Cooled Chillers The Life-Cycle Story

Many small to medium chiller plants use air cooled chillers with air-cooled screw chillers being common in the 165 to 565-ton range.

Positive displacement compression, no surge Avoid cooling towers Avoid condenser pumps & piping Avoid water costs Avoid chemical costs In a natural disaster there are no water issues Avoid high maintenance costs Saves mechanical room space Very good FL, ILPV & NPLVs Easier to control (no bypass) and operate (no

tower freezing) in cold climates Excellent choice for applications where

maintenance may be lacking Compressor work tracks drybulb not wet bulb Lower first cost

*Tip: Air cooled chillers do not require mechanical room space. To estimate the savings use $50/ft².

Air-Cooled Chillers The Life-Cycle Story

Design Performance rated at AHRI Condenser Relief: Traditional C.S Centrifugal

Evap Cond

Capacity

(ton)

Input

(kW)

Performance

(kW/ton)

RLA

(A)

NPLV

(kW/ton)

75% Load

(kW/ton)

50% Load

(kW/ton)

25 % Load

(kW/ton)

EWT

(°F)

LWT

(°F)

385.4 211.0 0.554 296 0.524 0.491 0.519 0.696 53.9 94.0

Traditional Constant-Speed (CS) WC centrifugal

Design Performance rated at AHRI Condenser Relief: Traditional VFD Centrifugal

Evap Cond

Capacity

(ton)

Input

(kW)

Performance

(kW/ton)

RLA

(A)

IPLV

(kW/ton)

75% Load

(kW/ton)

50% Load

(kW/ton)

25 % Load

(kW/ton)

EWT

(°F)

LWT

(°F)

385.4 223.4 0.580 312 0.377 0.427 0.330 0.418 54.0 94.1

Traditional Variable-Speed (VFD) WC centrifugal

“Hybrid” Variable-Speed (VFD) WC chiller Design Performance rated at AHRI Condenser Relief: “Hybrid” VFD Centrifugal

Operating Evap Cond

Capacity

(ton)

Input

(kW)

Performance

(kW/ton)

RLA

(A)

IPLV

(kW/ton)

75% Load

(kW/ton)

50% Load

(kW/ton)

25 % Load

(kW/ton)

EWT

(°F)

EWT

(°F)

385.4 230.8 0.599 314 0.329 0.424 0.287 0.259 54.0 94.3

Air-Cooled Chillers The Life-Cycle Story

Chiller Type

NPLV kW/Ton

Past A/C 0.980

Todays A/C 0.625

CS WC Centrifugal

0.587

VFD WC Centrifugal

0.480

“Hybrid” VFD WC Chiller

0.405

Chiller-only “Efficiency” Comparison

Full load tons = 385 W.C. includes tower fan & condenser pump energy cost

#1

#2

#3

#4

#5

Tower & Pump FL = 0.08kW/ton Tower & Pump PL = 0.06kW/ton

Air-Cooled Chillers The Life-Cycle Story

Chiller Type

NPLV kW/Ton

Chiller Op-Cost

$/yr

Op-Cost Improvement

%

Past A/C 0.980 $158,916 BASE

Todays A/C 0.625 $102,485 +35.6%

CS WC Centrifugal

0.587 $89,659 +43.6%

VFD WC Centrifugal

0.480 $75,934 +52.2%

“Hybrid” VDF WC

Chiller

0.405 $66,683 +58.0%

Chiller-only “Op-Cost”

Comparison

Full load tons = 385 Electrical rate = $0.08/kWh

W.C. includes tower fan & condenser pump energy cost

#1

#2

#3

#4

#5

Tower & Pump FL = 0.08kW/ton Tower & Pump PL = 0.06kW/ton

Air-Cooled Chillers The Life-Cycle Story

Utility rates have been increasing higher than inflation and GDP growth.

Air-Cooled Chillers The Life-Cycle Story

City of Houston Water Rates

Air-Cooled Chillers The Life-Cycle Story

A) HVAC Water Chillers & Cooling Towers: Fundamentals, Application & Operation, Herbert W. Stanford, Stanford White Associates, Consulting Engineers.

Total make-up water includes: • Evaporation • Drift • Blowdown…….0.0145/gpm (A)

Houston city water rates = $3.74/1000 gal

Total cost of water: $19,097 / year

FL GPM % Load % Run Time Hour/Year Gal/Yr

16.75 100% 1.00% 8760 88038

16.75 75% 42.00% 8760 2773197

16.75 50% 45.00% 8760 1980855

16.75 25% 12.00% 8760 264114

GAL/YR 5106204

385 Tons X 3 gpm/ton = 1155 gpm X .0145 = 16.75gpm

Tower Water Consumption 8-10 CC

Cooling Tower Make-up Water

Does NOT include sewer charges or additional maintenance associated with total cost of tower ownership

Chemical treatment cost = $3.00/1000 gallons

Total cost of chemicals: = $15,312 / year

Total cost of water & Chemicals: $34,409 / year

Air-Cooled Chillers The Life-Cycle Story

Chiller Type

NPLV kW/ton

Energy Cost $/yr

Water/ Chemicals $

Op-Cost $/yr

Op-Cost Improvement

Past A/C 0.980 $158,916 $NA $158,916 BASE

Todays A/C 0.625 $102,485 $NA $102,485 +35.6%

CS WC Centrifugal

0.587 $89,659 $34,409 $124,068 +21.9%

VFD WC Centrifugal

0.480 $75,934 $34,409 $110,343 +30.5%

“Hybrid” VFD WC Chiller

0.405 $66,683 $34,409 $101,092 +36.4%

Full Load Tons = 385.4 Electrical Rate = $0.08/kWh

#1

#3

#4

#2

#5

Chiller, tower, condenser pump, water & chemical op-cost comparison

Chiller “System” Op-Cost

Air-Cooled Chillers The Life-Cycle Story

Individual Item Contractor Sell Price

Todays Air-Cooled Chiller $227,487 ($591/ton)

Traditional CS WC Centrifugal Chiller $174,142 ($452/ton)

Traditional VFD WC Centrifugal Chiller $199,920 ($519/ton)

“Hybrid” VFD WC Chiller $244,174 ($634/ton)

Cooling Tower $40,000 ($103/ton)

Condenser Pump $3500

Condenser Piping $21,000

Water Treatment Equipment $4400

Additional Controls $4000

Refrigerant Monitor/Ventilation $4600

Mechanical Room Space $15,000

Total Tower/Pump Add $92,400 ($240/ton)

Chiller “Cost”

(Less Installation)

#4

#3

#2

#1

Add

Air-Cooled Chillers The Life-Cycle Story

Item Contractor Sell Price % Premium

Todays Air-Cooled Chiller $227,487 ($591/ton) Base Price

Traditional CS WC Cent Chiller + Tower

$266,542 ($692/ton) +17%

Traditional VFD WC Cent Chiller + Tower

$292,320 ($759/ton) +28%

“Hybrid” VFD WC Chiller Chiller + Tower

$336,574 ($874/ton) +47%

Note: Installation & Labor NOT Included

#1

#2

#3

#4

First Cost Only Important:

Nothing we’ve looked at so far tells the whole story…..

Equipment “Cost”

Less Installation

Air-Cooled Chillers The Life-Cycle Story

Item Contractor Sell $

15-Year Op-Cost $

Total LCC $

Best Lifetime Cost of Ownership

Todays Air-Cooled

Chiller

$227,487 $1,772,316 $1,999,803 BASE

CS WC Centrifugal

Chiller

$266,542 $2,412,102 $2,678,644 +$678,841

VFD WC Centrifugal

Chiller

$292,320 $2,200,528 $2,492,848 +$493,045

“Hybrid” VFD WC Chiller

$336,547 $1,748,226 $2,084,773 +$84,970

15-year savings include 2% per year utility escalation rate Op-cost does not include maintenance or upkeep

#1

#2

#3

#4

First Cost + Energy Cost

Air-Cooled Chillers The Life-Cycle Story

Item Op-Cost First-Cost Cost to Own

Todays Air-Cooled Chiller

#2 #1 #1

CS WC Centrifugal Chiller

#4 #2 #4

VFD WC Centrifugal Chiller

#3 #3 #3

“Hybrid” VFD WC Chiller

#1 #4 #2

Life-Cycle Cost Does not include maintenance or upkeep

Air-Cooled Chillers The Life-Cycle Story

• “Screw chillers usually require less maintenance than centrifugal chillers…”

• “Water-cooled systems always cost more to maintain due to the constant water treatment requirements and the need for regular tube cleaning… but generally last longer”.

• “…a reasonable estimate of the annual maintenance cost savings is $1000 to $2000 per year for the first 5-10 years (plus the cost of cooling tower maintenance, water and chemicals”.

*ASHRAE Fundamentals of Design and Control of Central Chilled-Water Plants, Steven T. Taylor, PE

Maintenance AC vs. WC

Air-Cooled Chillers The Life-Cycle Story