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BITZER RECIPROCATING COMPRESSORS FOR CO2
APPLICATIONS
BITZER Kühlmaschinenbau GmbH
Oliver Javerschek
BITZER // Uitnodiging CO2 Event // Page 2
TABLE OF CONTENTS
1. Preface
2. Important Aspects of CO2 Applications
3. Why BITZER?
4. Conclusions
Preface
BITZER // Uitnodiging CO2 Event // Page 4
COMMERCIAL REFRIGERATION WITH CO2:
NUMBER OF INSTALLATIONS
Reference: * Estimation of Shecco, ATMOSphere Europe 2015, BITZER
>68 / 114
--- / > 46
≈ 4000 / ≈ 2000
≈ 600 / 18
>30 / ≈ 10
≈ 3 / > 200
Transcritical
systems with
CO2: >5000 *
Subcritical
systems with
CO2: >3000BITZER: > 45 000 sold CO2 compressors,
mainly in commercial refrigeration!
Important Aspects of CO2 Applications
BITZER // Uitnodiging CO2 Event // Page 6
Booster system with common refrigerant circuit:� “Exchange” of heat energy, refrigerant mass flows & lubricant� Externally compounded two stage system, two stage expansion� Flash gas bypass
DEFINITION OF CO2 PROCESS CYCLES
BITZER // Uitnodiging CO2 Event // Page 7
OPERATING TEMPERATURES IN A BOOSTER
SYSTEM
/ High MT load and low LT load
� Low RGT for MT compressors
� Influence of FGB on RGT
/ Low MT and high LT load
� High RGT for MT compressors
Worst Case Scenarios on Load Conditions: MT / LT
140 °C
130 °C
40 °C
30 °C
140 °C
BITZER // Uitnodiging CO2 Event // Page 8
CAPACITY REGULATION
4HTC-20K @ t gc out 38 °C, to -8 °C, Toh 10 K = 23,4 kW
(100 %)
4HTC-20K @ tc 10 °C, to -8 °C, Toh 10 K = 47,0 kW (200 %)
Capacity regulation is
essential for CO2
applications:
full load = „easy“ & part
load = „challenging“
CR with 4KTC-10K, to -8 °C, Toh 10 K, f 65 .. 35 Hz, Qo ≈
const.
BITZER // Uitnodiging CO2 Event // Page 9
PARALLEL VS. FG - BYPASS SYSTEM
Influence on the operating conditions of the MT compressor stage
BITZER // Uitnodiging CO2 Event // Page 10
PARALLEL VS. FG - BYPASS SYSTEM
Lower heat sink temp. =
lower head pressure =
reduction of flash gas =
lower frequency
(capacity) of the parallel
compressor
Influence of reduced heat sink temperatures
BITZER // Uitnodiging CO2 Event // Page 11
PARALLEL VS. FG - BYPASS SYSTEM/ Application of an IHX (gas cooler outlet ↔ FGB) or other measures
● Significant difference for the MT suction: Parallel compression vs. FGB ● Avoiding wet operation during FGB operation
● Transition from parallel compression to FGB operation● Emergency operation with high heat sink temperatures
BITZER // Uitnodiging CO2 Event // Page 12
COP DEPENDENT ON AMBIENT TEMPERATURE
Based on:
Qo MT 20 kW @ - 8 °C / Qo LT 3 kW @ -32 °C, 40 bar medium pressure, ASHRAE 2009, Weather Data Viewer 4.0
Why BITZER?
BITZER // Uitnodiging CO2 Event // Page 14
SERVICES AND TRAINING
BITZER // Uitnodiging CO2 Event // Page 15
BITZER SOFTWARE TOOLS AND
DOCUMENTATION
Reference: Mark Twain, A Winning Hand
BITZER // Uitnodiging CO2 Event // Page 16
Undersquare stroke-bore ratios
All bearing seats feature
large surfaces
Multi-layer bearings
Specially treated piston surfaces, low average piston velocities, low pressure reduction per piston ring
Enforced connecting rods incl. bearings
Piston pin largely
dimensioned & large seating
WHY BITZER? EXPERIENCE IN ADVANCED
COMPRESSOR DESIGN!
BITZER // Uitnodiging CO2 Event // Page 17
WHY BITZER? EFFICIENCY!
BITZER // Uitnodiging CO2 Event // Page 18
BITZER COMPRESSORS FOR CO2
APPLICATIONS
tc max = 15 °C
The well-proven SL range for subcritical
applications with CO2 as refrigerant
/ LT stage of a cascade (hybrid) system
/ LT stage of an all CO2 booster system
/ MOP: HP 53 bar / LP 30 bar
to max = -15 °C
Compressors for transcritical applications
with CO2 as refrigerant
/ MT stage of an all CO2 booster system
/ CO2 heat pump system
/ ECO compressor in an parallel compression system
The new ME range for subcritical applications
with CO2 as refrigerant
/ MT application with high condensing temperatures
/ LT stage of an all CO2 booster system with a high
demand on standstill pressures
/ MOP: HP 100 bar / LP 100 bar
/ Two motor versions
tc max = 25 °C
to max = 0 °C
T: Transcritical applications
ME: High condensing and
high standstill pressures
SL: Low temp.
applications
BITZER // Uitnodiging CO2 Event // Page 19
BITZER CO2 COMPRESSORS - CERTIFIED
PRODUCTS!
/ Since three years BITZER is the only manufacturer
/ 17 models for subcritical CO2 applications (2011)
/ 9 + 3 models for transcritical CO2 applications (2012, 2015)
Conclusions
BITZER // Uitnodiging CO2 Event // Page 21
CONCLUSIONS
Premise for a successful CO2 installation:
/ Observation of operating temperatures
/ Correctly balanced capacity regulation
/ Focus on annual energy efficiency
BITZER provides the most beneficial CO2 compressor offering:
/ Three product families for a wide field of CO2 applications
/ Technical documentation and software
/ Technical training, individual support and special services
BITZER CO2 compressors set new standards and show the benchmark
/ Trendsetting technology
/ Highest efficiency and reliability
/ ASERCOM certified products