Trane Geister

W.
Ryan Geister
CenTraVac Product Manager Vertical Markets
Trane 3600 Pammel Creek Road LaCrosse WI 54601 7599 TEL 608 787 3881 FAX 608 787 2204 rgeister@trane.com
An American Standard Company
Energy First Cost Consumption
Annual Energy Cost Conventional Chilled Water System
Past ...
Chiller 73%
1980
Pumps 18%
Tower 9%
Present ...
Chiller 58%
2000
Pum ps 26%
Tower 16%
Low Flow Chilled Water Plant Design
A Paradigm Shift - New Rules of Thumb
New rules of thumb

44 41 F chilled water supply 16 F T across the evaporator
thats at 1.5 gpm/ton
15 F T across the condenser
thats at 2.0 gpm/ton
Resize the cooling tower accordingly
Low Flow Chilled Water Plant Design
What are others saying???
Kelly and Chan (Vanderweil Engineering)

HPAC January 1999: Optimizing Chilled Water Plants Chilled water T: 18 & Condenser water T: 14.2F
With the same cost chillers, at worst, the annual operating cost with lower flows be about equal to standard flows but still at a lower first cost
PG&E: CoolTools

Chilled water T: 12F to 20 F Condenser water T: 12F to 18 F (multi-stage)

kWh/ton/year
600 400 200 0 41/16 42/14 43/12 44/10 Chilled water pump Chiller
Chilled water supply temperature/DeltaT
EarthWise Chilled Water Systems:
Good for Business...
Offers lower first cost and lower operating cost. Reduced utility generated greenhouse gas emissions.
Good for the Environment:
Reduces pumping costs...
A low flow, low temp, high efficiency system

control s
Leverages todays technology
Equipment - Chillers, Controls System options
+$
$
piping, pumps
+$
chillers
Q= m cp T Fundamental Laws
Mass (capacity) varies directly with flow

>
T = Smaller Pipes & Tower P = Smaller Pumps
Pressure Drop varies with the square of the flow

<
Energy Consumption varies with the cube of the flow

Reduced
Operating Costs!
The Next Step...
How have Chillers Reacted to VPF Traditionally???

130 1,500.00 120
Capacity Control w/o Water Flow Compensation
1,300.00
110
1,100.00
100
Evaporator Water Flow
900.00
Water Temp [degF]
80
500.00
70
60
Too Fast a change can be a problem
300.00
100.00
Evap Entering Water Temp
50
-100.00
40
Chiller on
Evap Leaving Water Temp
-300.00
Chiller off Chiller off
30 0:00:00
0:10:00
0:20:00
0:30:00
0:40:00
-500.00 0:50:00
Time (hour:min:sec)
Water Flow [gpm]
90
700.00
But Newer Technology Can Eliminate all Concerns

130 1,500.00 120
Capacity Control with Water Flow Compensation
1,300.00
110
1,100.00
100
900.00
Water Temp [degF]
90
Evaporator Water Flow
700.00
80
70
Stable Chiller Response

Evap Entering Water Temp
500.00
300.00
60
100.00
50
-100.00
40
Evap Leaving Water Temp
-300.00
30 0:00:00
0:10:00
0:20:00 0:30:00 Time (hour:min:sec)
0:40:00
-500.00 0:50:00
Water Flow [gpm]
Bottom line: Chillers very capable today! & VPF Saves $$$
And... By coupling VPF Systems with SERIES Evaporators, many advantages emerge...
System Examples
Series Chillers & colder water = $ savings!
How???
CHILLED WATER RETURN CHILLED WATER SUPPLY
57 o F
49 o F
105 o F
41 o F
56 o F 64 o F
Assuming 85 Entering and 2 GPM/Ton
Run two chillers at 50% or..

41 oF
49 oF
Even better...
CHILLED WATER RETURN
Part Load Efficiency

CHILLED WATER SUPPLY
57 o F
57 o F
105 o F
41 o F
.Run your most efficient chiller
64 o F
41 o F
If applicable...
Chilled Water Temperature Re-Set

57 o F
57 o F
105 o F
44 o F
And save more $$$s!
61 o F
44 o F
If applicable...
AFD Chiller
57 o F
57 o F
41 o F
And save more $$$s!*

* IF all three justify the initial capital cost of the AFD
1. Extensive hours of operation (~24/7, winter cooling) 2. Access to inexpensive cold condenser water 3. Expensive electricity (high kWh rates)
System Flexibility Options... Absorption Chiller Technology

57 o F
50 o F
41 o F
System Flexibility Options... Screw Chiller Technology

57 o F
50 o F
41 o F
System Flexibility Options... Existing Chiller Assets

57 o F
50 o F
41 o F
Existing Chiller Assets
System Flexibility Options...

Plant Expansion
Parallel - Primary Secondary (Decoupled)

~50 oF
57 oF
41 oF
System Flexibility Options...

Plant Expansion
Parallel/Series - Variable-Primary
CHILLED WATER RETURN 57 oF
~50 oF
41 oF
EarthWise Chilled Water Systems

Exploit technology! Low flow Low temperature High efficiency Leverage: Optimized Controls Variable Primary Flow Series Evaporators
First Operating Cost Cost
always, always,
Always Remember
W. Ryan Geister
CenTraVac Product Manager Vertical Markets
Trane 3600 Pammel Creek Road LaCrosse WI 54601 7599 TEL 608 787 3881 FAX 608 787 2204 rgeister@trane.com
An American Standard Company

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Energy First Cost Consumption

Annual Energy Cost Conventional Chilled Water System

Low Flow Chilled Water Plant Design

A Paradigm Shift - New Rules of Thumb

New rules of thumb

44 41 F chilled water supply 16 F T across the evaporator

thats at 1.5 gpm/ton

15 F T across the condenser

thats at 2.0 gpm/ton

Resize the cooling tower accordingly

Low Flow Chilled Water Plant Design

What are others saying???

Kelly and Chan (Vanderweil Engineering)

Chilled water T: 12F to 20 F Condenser water T: 12F to 18 F (multi-stage)

Chilled water supply temperature/DeltaT

EarthWise Chilled Water Systems:

Good for Business...

Good for the Environment:

Reduces pumping costs...

A low flow, low temp, high efficiency system

Leverages todays technology

Equipment - Chillers, Controls System options

Mass (capacity) varies directly with flow

T = Smaller Pipes & Tower P = Smaller Pumps

Pressure Drop varies with the square of the flow

Energy Consumption varies with the cube of the flow

The Next Step...

How have Chillers Reacted to VPF Traditionally???

Capacity Control w/o Water Flow Compensation

Water Temp [degF]

Too Fast a change can be a problem

Evap Entering Water Temp

Water Flow [gpm]

But Newer Technology Can Eliminate all Concerns

Capacity Control with Water Flow Compensation

Water Temp [degF]

Evaporator Water Flow

Stable Chiller Response

0:20:00 0:30:00 Time (hour:min:sec)

Water Flow [gpm]

Series Chillers & colder water = $ savings!

Assuming 85 Entering and 2 GPM/Ton

Run two chillers at 50% or..

Part Load Efficiency

.Run your most efficient chiller

Chilled Water Temperature Re-Set

And save more $$$s!

And save more $$$s!*

System Flexibility Options... Absorption Chiller Technology

System Flexibility Options... Screw Chiller Technology

System Flexibility Options... Existing Chiller Assets

Existing Chiller Assets

System Flexibility Options...

Parallel - Primary Secondary (Decoupled)

CHILLED WATER SUPPLY

System Flexibility Options...

CHILLED WATER RETURN 57 oF