This document discusses a transcritical CO2 condensing unit driven by DC inverter technology for small format stores. It notes that CO2 has a GWP of 1 and is a natural refrigerant, and that regulations in Europe and the US are driving adoption of more efficient and environmentally friendly technology. The document then describes CAREL's Hecu sistema solution, which uses DC inverter compressors and advanced control algorithms to significantly improve energy efficiency at partial loads compared to on/off systems, while maintaining food quality and reliability.

1. Transcritical CO2 condensing unit driven by DC
inverter technology for small format stores
Nicola Pieretti
Application Manager

2. Any reproduction, modification or distribution of this document, whether in part or entirely and by any means, is expressly prohibited except upon CAREL's
express prior written permission. 2017 CAREL all rights reserved
GWP=1
CO2
Condensing unit regulation
EUROPE Ecodesign “Directive”
USA DOE “CFR 2015 Title 10 part 431”
EUROPE “ F-GAS regulation No. 517/2014”
USA “EPA SNAP Rules”
Performance
Refrigerant
Natural Efficiency available now
DC
Technology

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express prior written permission. 2017 CAREL all rights reserved
CO2 condensing unit scenario

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express prior written permission. 2017 CAREL all rights reserved
Hypermarket – Supermarket
Big - Medium formats
•Compressor racks, mainly CO2
transcritical booster
•Natural refrigerant CO2 as standard
•Continuous improvement for energy
efficiency mostly in warm climates
•Carbon footprint reduction
Convenience store –
Petrol Station
Small – Extra small formats
•Condensing Units
•Natural refrigerant CO2 available
•Partial load energy efficiency
•Carbon footprint reduction
Extended range
CO2 condensing unit application

5. Any reproduction, modification or distribution of this document, whether in part or entirely and by any means, is expressly prohibited except upon CAREL's
express prior written permission. 2017 CAREL all rights reserved
System solution in compact,
fully-integrated equipment
now available also for Low
Temperature application
Hecu sistema
Totally Green
Full range of available CO2 compressors in the market

6. Any reproduction, modification or distribution of this document, whether in part or entirely and by any means, is expressly prohibited except upon CAREL's
express prior written permission. 2017 CAREL all rights reserved
Hecu sistema
New efficiency frontier
No Food waste
Innovation suitable for all
Always connected

7. Any reproduction, modification or distribution of this document, whether in part or entirely and by any means, is expressly prohibited except upon CAREL's
express prior written permission. 2017 CAREL all rights reserved
New efficiency frontier
DC inverter technology
The compressor with DC motor allows considerable energy saving as operation is optimum at part loads.
On-Off cycling is not efficient as the
refrigeration circuit needs time to reach the
nominal efficiency. Part load conditions (i.e.
25%) won’t allow to reach nominal
efficiency. Average efficiency is low.
This area represents the increase of
efficiency at part load. It’s bigger with a
wider BLDC capacity range
Refrigeration plant is working for the
largest part of the time at low partial
load

8. Any reproduction, modification or distribution of this document, whether in part or entirely and by any means, is expressly prohibited except upon CAREL's
express prior written permission. 2017 CAREL all rights reserved
New efficiency frontier
Integrated Solution for System Optimization
Four main functions to improve system efficiency
 CO2 Transcritical Cycle Management
 Continuos superheat modulation: Smooth Line
 Floating Suction for self adapting working conditions
 Compressors speed modulation to match real system cooling demand
CO2 Transcritical Cycle Management
Transcritical operating condition, HPV
valve works with a dynamic setpoint to
maximise compressor COP
Smooth transition from transcritical to
subritical operating condition and viceversa
Subcritical operating condition, HPV valve
maintains a stable values of subcooling

9. Any reproduction, modification or distribution of this document, whether in part or entirely and by any means, is expressly prohibited except upon CAREL's
express prior written permission. 2017 CAREL all rights reserved
New efficiency frontier
ADAPTIVE WORKING
CONDITION
to avoid ON-OFF
cycles
Smooth Lines
• Continuous superheat set point modulation according to real unit demand
• Dynamic modulation of cooling capacity results in no more off cycles
• Stable product temperature and less defrost needs
• High efficiency and stability with CAREL EEV
SH
set
Regulation temp.

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express prior written permission. 2017 CAREL all rights reserved
Floating Suction & Compressor speed modulation
• Continuous suction pressure set point modulation
• Optimum and stable control suction pressure control
• Compressor ON-OFF cycles reduced to the minimum
• High efficiency and stability with CAREL power+
REAL TIME
SYNCHRONIZATION
with evaporator
request weighted by
capacity
• Wide and real
capacity modulation
• NO ON-OFF cycles
New efficiency frontier

11. Any reproduction, modification or distribution of this document, whether in part or entirely and by any means, is expressly prohibited except upon CAREL's
express prior written permission. 2017 CAREL all rights reserved
Seasonal effect of High Pressure Optimization
Night/day effect of Floating suction
• LOWEST possible compression ratio fitted
efficiently with lower compressor speed
• MINIMUM possible refrigerant flow-rate through
the heat exchangers increasing efficiency
New efficiency frontier

12. Any reproduction, modification or distribution of this document, whether in part or entirely and by any means, is expressly prohibited except upon CAREL's
express prior written permission. 2017 CAREL all rights reserved
Innovation suitable for all
Unique controller board
For BLDC compressor management and
CO2 valves management, both high
pressure and flash gas valves
Advanced DC compressor driver
For an efficient and variable speed
compressor driving and optimal
performance at partial load
Electronic expansion valves
For a calibrated injection and precise
regulation of gas cooler and receiver
pressure
Fully integrated and compact solution
ALL in ONE

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express prior written permission. 2017 CAREL all rights reserved
Maximum ease of use
Easy set-up and
optimisation
• Wizard start-up procedure for
a simplified unit configuration
• Pre-setting of the main
parameters and probes to
reduce commissioning timing
Extremely fast
commissioning
• Automatic preconfiguration of
the system network
(refrigerated cases and
condensing unit)
• Optimised default parameters
with extensive laboratory tests
Intuitive programming
• Different access profile for
different user
• Simplified menu for a clear
navigation
• PGD and pLD PRO terminal
with full informations
Innovation suitable for all

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express prior written permission. 2017 CAREL all rights reserved
Food quality
Full envelope management and optimum compressor
control
CAREL testing process approves the use of its inverter with different
models of compressors to ensure completely safe operation in the best
possible conditions.
• Detailed qualification process
• Perfect control of compressor envelope
• Safety procedures
Advanced oil return features
• By washing the showcases using CAREL E2V expansion valves
This software function exploits communication with the showcases to
lower the valve superheat set point and thus recover the oil that
deposits on the evaporators, through periodical washing cycles
• With Speed Boost function
This software function makes the compressor work at a sufficiently high
speed to assist oil return
Extreme reliability  no down time

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express prior written permission. 2017 CAREL all rights reserved
Food quality
Highest quality of food preservation combined with high energy efficiency
The condensing unit constantly responds to the cooling demand of each connected unit, dynamically
adapting to current conditions while the E2V valves on each unit control the flow of refrigerant, and the
MPXPRO controllers minimize temperature fluctuations

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express prior written permission. 2017 CAREL all rights reserved
Always connected
Direct data access and
notification
With optimized interface for
different device and configurable
report
GPRS-ETHERNET
Simple and deep MAINTENANCE
Fully independent access to the
refrigeration unit to maximize the
maintenance experience
Intuitive site navigation
With custom maps and graphics
Easy optimization and higher
service level
With site graphs and trend

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express prior written permission. 2017 CAREL all rights reserved
Always connected
ENERGY CONSUMPTION
Systems comparison and Business Intelligence within all units connected
• Energy dashboard with comparative
analysis
• Analytics for optimal food preservation
• Centralized alarm monitoring
• Remote customized interface
• Geo localization

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express prior written permission. 2017 CAREL all rights reserved
Hecu sistema in details
Medium Temperature application Low Temperature application

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express prior written permission. 2017 CAREL all rights reserved
Conclusions
• CO2 DC inverter and compressors are available in the market
• Considerable energy saving results can be obtained by DC technology and
advanced control algorithms
• Both efficiency and refrigerants regulations can be achieved using DC inverter
technology and natural refrigerant CO2
• Optimum food preservation with more stable product temperature
• Hecu sistema has extended its range of solutions for CO2 applications

20. Any reproduction, modification or distribution of this document, whether in part or entirely and by any means, is expressly prohibited except upon CAREL's
express prior written permission. 2017 CAREL all rights reserved
Concept unit @Euroshop
Natural Efficiency available now