Making the Best Choice:
Optimizing Compressor Applications
Dayton, Ohio
May 10, 2016
System Capacity Modulation Strategies
• Single-compressor condensing unit
Unloader types
• Parallel duo-mate rack
• Even parallel four-by-four rack
• Uneven parallel rack
• Hp limits / extended body racks
• VFD and swing compressor
• Digital Discus™ capacity modulation
Digital
Available Products and Technologies
Hot gas bypass
(Fixed step)
Blocked suction
(Fixed step)
Digital
compressor
10–100%
Variable
frequency drive
50–100%
Recip




Scroll



Screw

Copeland Discus™
with blocked suction

Copeland Discus
digital
Variable
displacement

(two-step)

(25%–100%)
Copeland Scroll
digital
Modulation Technologies
Pros
Cons
Hot gas bypass
• System-based design
• Efficiency
• Compressor reliability
Blocked suction
• Efficiency
• Cost
• Reliability
• Ease of service
• Less precise control
• No option on single-bank
• Precise control
• Moderate cost
• Minimal efficiency loss on
• Precise control
• Modulated capacity efficiency
• Cost
• Electrical noise
• Reliability
• Precise control (with infinitely
• Low-capacity efficiency
Digital compressor
Variable frequency drive
Variable displacement
variable systems)
compressor designs
modulated capacity
Parallel Rack Historical Design Evolution
Early rack configurations
23
50% capacity unloading
Poor load matching
Significant compressor cycling
High inrush current
23
46 Hp
Rack A – traditional configuration (actual store)
15
15
8
5
3
6D
6D
4D
3D
2D
46 Hp
Increased steps of unloading
Better load matching
More compressors needed
Increased equipment costs
Rack A – configuration with Digital (actual store)
15
12.5
12.5
6
6D
4D
4D
3D
Digital
46 Hp
Variable unloading up to 90%
Excellent load matching
Reduced number of compressors
Lower capital equipment costs
Digital Can Provide Continuous Modulation Over Larger Capacities
• Used in parallel racks with fixed capacity
compressors
– Wider range of capacities
Capacity (Hp)
Digital
Digital
Fixed
capacity
#2
• Acts like a swing compressor
– Without the cost of a VFD
– With extended unloading
• Down to 10% vs. 50%
– Avoids the oil issues associated with VFDs
Digital
Fixed
capacity
#1
Fixed
capacity
#1
• One Digital per suction group
– Optimized cycling of existing compressors
– Can be applied with any brand compressor
Copeland Digital Compressor Technology
• Copeland compressor with continuous
capacity control:
–
–
–
–
Scroll: 10–100%
3D: 10–100%
4D: 50–100%
6D: 33–100%
System
needs 50%
capacity
Here is how
to deliver
50% capacity
Digital control
module
• Applicable on new and existing compressors
– Scroll
– Discus
P
P
10
10
10
10
10
P
0
20
• Patented technology
Time (sec)
40
10
50%
capacity
60
Temperature
Tightens temperature control
Copeland
Scroll
Digital
Time
Copeland Discus
Digital
Results in Narrow Operating
Temperature Range
Blocked Suction vs. Copeland Digital Technology
Here is how to deliver
20% capacity desired
by system
Controller
decides
10–100%
capacity
Controller decides 50% or 100% capacity:
100% — both banks loaded
50% — energize unloader
1 bank unloaded / 1 bank loaded
20%
Digital
Control
module
50%
100
100
50
50
0
Compressor capacity
0
Compressor
Capacity
4
16
20
4
16
4
16
40
60
Time (sec)
4
16
80
20% Capacity
Blocked Suction Unloader Offers Only 100%, 50% or 0%
Capacity Options; Limited to 10 Cycles per Hour
Discus Digital Provides Continuous Capacity
Modulation From 10% to 100%.
Copeland Digital Technology Benefits
• Precise control of suction pressure and temperature
– Longer shelf life and less food shrink because of minimal food temperature fluctuations
– More consistent TXV operation
• Reduced cycling of compressors
– Extends contactor life
– Extends compressor life
• Reduced defrost cycle time
– Tighter temperature control minimizes formation of frost on evaporator
• System efficiency improvement
– Eliminates over/under shooting of suction pressure setpoint
– Allows increasing suction pressure setpoint
– Reduces inrush current / power usage
• Paradigm shift in parallel system design
– No need for uneven paralleling for compressor staging
– Using common compressor selections simplifies replacement needs
Copeland Digital Technology Applications
• Temperature ranges
– High-temp
— Medium-temp
— Low-temp
• Refrigerants
– R-22, R-404A and R-507, R-407A and R-407C, R-448A and R-449A
• Floating head pressure capability
– Low temperature down to 40 °F condensing
– Medium temperature down to 50 °F condensing
• System configurations
– Single-compressor condensing units
– Even parallel racks
– Uneven parallel racks
– Parallel racks with satellite compressors
– Split-suction parallel racks
– Secondary fluid-cooling systems
Discus Digital Field Experience
Canadian supermarket in Halifax, Nova Scotia
Medium-Temp., Rack-Suction Pressure
Rack suction pressure range narrows significantly with Discus Digital
Before Digital
Product degradation
6 psi
39 psi
Suction pressure:
After Digital
85% tighter
control
Excessive operating costs
Dairy Case With Discus Digital Activated
Case temperature range narrows significantly with Discus Digital
Before Digital
Case temperature:
After Digital
Product degradation
15 °F
1.25
°F
92% tighter
control
Excessive operating costs
Meat Case With Discus Digital Activated
Case temperature range narrows significantly with Discus Digital
Before Digital
Case temperature:
Product degradation
After Digital
88% tighter
control
17 °F
2 °F
Excessive Operating Costs
Five-Compressor Rack With Discus Digital Activated
Compressor cycling reduced by 56% with Discus Digital
Before Digital
After Digital
Compressor Cycling:
3DS3R17ML-TFE-A23
(08E03844R)
Comp 5
3DB3R12ML-TFE-A23
(08E01922R)
Comp 4
3DB3R12ML-TFE-A23
(08E03087R)
Comp 3
3DB3R12ML-TFE-A23
(08E03088R)
Comp 2
3DSDR17ML-TFE-A23
(08E03845R)
Comp 1
56% reduction
Digital retrofit
Discus Digital Upgrade in Atlanta, GA
• 40,000 sq. ft. supermarket; HillPHOENIX racks constructed in 2003
• Clean machine house with plenty of space
• Retrofit (1) compressor per rack
• Plenty of space available in control panels
• One knowledgeable technician (26 years of experience)
- Familiar with store prior to project
• CTs installed to monitor energy consumption for the rack, condensers and
compressors
• ESRs present for case temperature control
Rack 3 MT (R-22) 300 MBTU
• 4 Compressors
1. 2DA3-075L-TFD
7.5 Hp
2. 3DB3A100L-TFD* 10 Hp
3. 3DF3A120L-TFD
12 Hp
4. 3DS3A150L-TFD
15 Hp
*Compressor upgraded to Discus Digital
Rack 4 LT (R-22) 160 MBTU
• 5 Compressors
1. 2DF3-030L-TFD
3 Hp
2. 3DB3A075L-TFD* 7.5 Hp
3. 3DF3A090L-TFD
9 Hp
4. 3DS3A100L-TFD
10 Hp
5. 4DL3A150L-TSK
15 Hp
Rack 3 MT +10
After
• Tighter suction pressure
• Higher average suction pressure
• Tighter case temperature
(Discus Digital Enabled)
60
Average Daily Cycles
Before
50
40
80% Avg Cycle
Reduction!
30
20
10
0
Comp 1Comp 2Comp 3Comp 4
Comp 1 DGTL Comp 3Comp 4
Rack 4 LT -20
After
•Tighter suction pressure
•Higher average suction pressure
•Tighter case temperature
•Reduced defrost time
(Discus Digital enabled)
25
Average Daily Cycles
Before
20
15
12% Avg Cycle
Reduction
10
5
0
Comp Comp Comp Comp Comp
1
2
3
4
5
Comp DGTLComp Comp Comp
1
3
4
5
Standard unloading
Digital unloading
Copeland Discus Digital Field Testing Experience
Digital benefit
A.
B.
C.
D.
E.
Carmel, IN
Grove City, OH
Middletown, OH
Nova Scotia, CN
Statesville, NC
Average =
Reduction in
compressor cycling
63%
91%
95%
56%
78%
77%
Suction pressure
change
67%
64%
50%
85%
33%
60%
Copeland Digital Compressor Selection Guideline
• For optimum suction pressure control, the following guideline is recommended in the selection
of digital and fixed compressors, per suction header:
–
–
–
–
–
D ≥ F1
F2 ≤ D + F1
F3 ≤ D + F1 + F2
……
FN ≤ D + F1 + F2 + ….+ FN-1
• In the above equations,
– D is digital capacity or horsepower
– F1, …FN are fixed speed compressor capacity
or horsepower
Example:
• Assume five-compressor system
• Pick Digital as D = 10 Hp
• Per rule, one fixed compressor, F1 , should be 10 Hp or less
•
Pick F1 = 10 Hp
• Per rule, second fixed compressor, F2 , should be 11 Hp or less
•
Pick F2 = 7.5 Hp
• Per rule, third fixed compressor, F3 , should be 18.5 Hp or less
•
Pick F3 = 7.5 Hp
• Per rule, fourth fixed compressor, F4 , should be 36 Hp or less
•
Pick F4 = 7.5 Hp
• Final compressor selections should total up to max capacity needed
to match load
Note! For Best Results, the Digital Compressor Should Be the Lead Compressor.
It Should Be the First Compressor on and the Last Compressor off!
Copeland Discus Digital Selection Example 1
• Consider the following MT suction group:
1. 3DB3R12ME-TFD
2. 3DF3R15ME-TFD
3. 3DS3R17ME-TFD
• Before selecting the compressor to upgrade to Digital, verify that it will cover the “gaps” in
between capacity steps
– 3DB3R12ME-TFD  120,000 BTUH
– 3DF3R15ME-TFD  150,000 BTUH
– 3DS3R17ME-TFD  170,000 BTUH
Copeland Discus Digital Selection Example 1
• Apply the compressor selection guideline:
–
–
–
–
–
D ≥ F1
F2 ≤ D + F1
F3 ≤ D + F1 + F2
……
FN ≤ D + F1 + F2 + ….+ FN-1
• For 3DBDR12ME:
– 120,000 (3DBD) > 150,000 (3DF3) X
– 170,000 (3DS3) ≤ 270,000 (3DF3 + 3DBD) P
Selecting the 3DB3 as a Digital would NOT satisfy the guideline!
• For 3DFDR15ME:
– 150,000 (3DFD) > 120,000 (3DB3) P
– 170,000 (3DS3) ≤ 270,000 (3DB3 + 3DFD) P
Selecting the 3DF3 as a digital will satisfy the guideline!
Resulting Capacity Staging With 3DBD
Staging with standard compressors
Staging with Digital compressor
Compressor Capacity (Btu/hr)
Gaps in
capacity
steps
3DB3
Confidential
3DF3
3DS3
3DF3
3DS3
3DBD
Resulting Capacity Staging with 3DFD
Staging with standard compressors
Staging with Digital compressor
Compressor Capacity (Btu/hr)
NoGaps
gaps!In
Capacity
Steps
3DB3
Confidential
3DF3
3DS3
3DB3
3DS3
3DFD
Copeland Discus Digital Selection Example 2
• Consider the following MT suction group:
1. 3DA3R10ME-TFD
2. 3DF3R15ME-TFD
3. 3DS3R17ME-TFD
4. 4DE3R18ME-TSK
(one-bank unloader compressor)
• Before selecting the compressor to upgrade to Digital, verify that it will cover the “gaps” in between
capacity steps
– 3DA3R10ME-TFD  100,000 BTUH
– 3DF3R15ME-TFD  150,000 BTUH
– 3DS3R17ME-TFD  170,000 BTUH
– 4DE3R18ME-TSK  180,000 (90,000) BTUH
Copeland Discus Digital Selection Example 2
• Apply the compressor selection guideline:
–
–
–
–
–
D ≥ F1
F2 ≤ D + F1
F3 ≤ D + F1 + F2
……
FN ≤ D + F1 + F2 + … + FN-1
• For 3DADR10ME:
– 100,000 (3DAD) > 90,000 (4DE3* unloaded) P
– 150,000 (3DF3) ≤ 190,000 (4DE3* unloaded + 3DAD) P
– 170,000 (3DS3) ≤ 340,000 (4DE3* unloaded + 3DF3 + 3DAD) P
Resulting Capacity Staging
Staging with standard compressors
Staging with Digital compressor
Compressor Capacity (Btu/hr)
No gaps!
4DE3
4DE3 (Unl)
Confidential
3DF3
3DS3
3DA3
4DE3
4DE3 (Unl)
3DF3
3DS3
3DAD
Copeland Discus Digital Upgrade Requirements
• Copeland’s guideline:
– Best choice: install new Discus Digital compressor
– If compressor is less than four years old, then valve plate upgrade retrofit kit is available
• Discus Compressor produced with a serial number of 99C (March 1999) or older are NOT
physically capable of being upgraded
– Also indicated in the model nomenclature
• Old nomenclature: “A” in the fifth character (e.g., 3DS3A150E-TFD-200)
• New nomenclature: all compressors (e.g., 3DS3R17ME-TFD-200)
• System controller with variable capacity control
– Controller must be capable of directly cycling the digital solenoid or provide a variable voltage output
• Copeland recommends the E2 system controller (version 2.3 or later)
• More information in Application Bulletin AE4-1373
Digital Technology Support Material
Marketing bulletin
Overview presentation
Press release
Website
Animation
Brochure
Field upgrade
installation video
Cut sheet
Application engineering
bulletins
Thank You!
Questions?
DISCLAIMER
Although all statements and information contained herein are believed to be accurate and reliable, they are presented without guarantee or warranty of any kind, expressed or
implied. Information provided herein does not relieve the user from the responsibility of carrying out its own tests and experiments, and the user assumes all risks and liability for
use of the information and results obtained. Statements or suggestions concerning the use of materials and processes are made without representation or warranty that any such
use is free of patent infringement and are not recommendations to infringe on any patents. The user should not assume that all toxicity data and safety measures are indicated
herein or that other measures may not be required.
30
Backup
31
Discus Digital Refrigerant Gas Flow
Loaded
Enters compressor
2. Passes through body
3. Into valve plate
4. Compressed by pistons
5. Exits compressor
1.
Valve assembly routes suction gas
above unloader pistons
Unloader pistons allow suction gas
flow into valve plate
Discus Digital Refrigerant Gas Flow
Unloaded
1.
2.
3.
Enters compressor
Passes through body
Unloader pistons block gas
before entering valve plate
Valve assembly routes discharge gas
above unloader pistons
Unloader pistons block suction gas
flow into valve plate
Copeland Discus Product Lineup (MT R-404A, 20/120/65/0 °F, 60 Hz)
Digital:
Not applicable
P
P
P
P
P
P
P
P
P
P
P
P
Copeland Discus Product Lineup (LT R-404A, -25/105/65/0 °F, 60 Hz)
Digital:
Not applicable
P
P
P
P
P
P
P
P
P
Copeland Scroll Digital
• Scroll compressor with digital modulation capability that
offers continuous capacity control from 10% to 100%
• Unloading and loading is accomplished by separating the
scroll sets axially
• Indicated by a “D” in the third character of the compressor
model number
– e.g., ZBD45KCE-TFD-200
Copeland Scroll
Digital
Copeland Scroll Digital Compressor Operation
• Capacity modulation is achieved by axially
separating scrolls
Unloaded
(No compression)
– When “separated”, no gas compression and
~10% power usage
• Varying the amount time the scroll sets are
separated, capacity from 100% down to 10%
can be achieved
Loaded
• Separation is accomplished by bypassing a
controlled amount of discharge gas to the
suction through a solenoid valve
Copeland Scroll Product Lineup (MT R-404A, 20/120/65/0 °F, 60 Hz)
Digital:
P
P P P
P
P
P
Copeland Discus Product Lineup (LT R-404A, -25/105/65/EVI SC °F, 60 Hz)
Digital:
P
P
P
P
P
P
Expanding MT Product Portfolio
Medium-temperature capacity (BTU)
140
Supermarket
Process chiller
120
Walk-ins
Frozen carbonated beverage
100

80

60


40

20
0
Model
HP
ZB10
1.5
ZB15
2
ZB19
2.5
Fixed capacity models
Emerson Confidential
ZB21
3
ZB26
3.5
ZB29
ZB30
4
ZB38
5
ZB45
6
ZB50
7
ZB58
ZB66
ZB76
ZB95
ZB114
8
9
10
13
15
Digital modulated and fixed capacity models

New MT Digital models