Canadian Patents Database / Patent 2744840 Summary

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(12) Patent: (11) CA 2744840
(54) English Title: CO2 REFRIGERATION SYSTEM
(54) French Title: SYSTEME FRIGORIFIQUE PAR CO2
(51) International Patent Classification (IPC):
  • F25B 9/00 (2006.01)
(72) Inventors (Country):
  • DUBE, SERGE (Canada)
(73) Owners (Country):
  • DUBE, SERGE (Canada)
(71) Applicants (Country):
  • DUBE, SERGE (Canada)
(74) Agent: NORTON ROSE FULBRIGHT CANADA LLP/S.E.N.C.R.L., S.R.L.
(45) Issued: 2014-01-28
(22) Filed Date: 2009-10-23
(41) Open to Public Inspection: 2010-04-29
Examination requested: 2011-06-22
(30) Availability of licence: N/A
(30) Language of filing: English

(30) Application Priority Data:
Application No. Country Date
61/107,689 United States of America 2008-10-23
61/166,884 United States of America 2009-04-06
61/184,021 United States of America 2009-06-04

English Abstract

A CO2 refrigeration system comprises a refrigeration circuit in which circulates CO2 refrigerant between a compression stage in which the CO2 refrigerant is compressed. A condensation stage is provided in which the CO2 refrigerant releases heat and is accumulated in a condensation reservoir. An evaporation stage is provided in which the CO2 refrigerant is expanded to a gaseous state to absorb heat from a fluid for refrigeration, with at least a portion of CO2 refrigerant exiting the evaporation stage being directed to a supra-compression circuit comprising a supra-compression stage in which the portion of CO2 refrigerant is compressed. A heat exchanger is provided by which the compressed CO2 refrigerant is in a heat-exchange relation with a secondary-refrigerant circuit, such that the compressed CO2 refrigerant releases heat to a secondary refrigerant used for heating purposes. Pressure-regulating means control a pressure of the compressed CO2 refrigerant being returned to the condensation stage.


French Abstract

Un système frigorifique par CO2 comprenant un circuit de réfrigération où circule du réfrigérant au CO2 après un étage de compression dans lequel le réfrigérant au CO2 est comprimé. Un étage de condensation est utilisé, dans lequel le réfrigérant au CO2 dégage la chaleur et est accumulé dans un réservoir de condensation. Un étage d'évaporation est utilisé, dans lequel le réfrigérant au CO2 est dilaté en un état gazeux pour absorber de la chaleur d'un fluide pour la réfrigération, au moins une partie du réfrigérant au CO2 sortant de l'étage d'évaporation étant dirigé vers un circuit de surcompression comprenant un étage de surcompression dans lequel la partie de réfrigérant au CO2 est comprimée. Un échangeur de chaleur est utilisé, par lequel le réfrigérant au CO2 comprimé est dans une relation d'échange de chaleur avec un circuit de réfrigérant secondaire, de sorte que le réfrigérant au CO2 comprimé dégage de la chaleur vers un réfrigérant secondaire utilisé à des fins de chauffage. Des moyens de régulation de pression commandent la pression du réfrigérant au CO2 comprimé étant retourné vers l'étage de condensation.


Note: Claims are shown in the official language in which they were submitted.

CLAIMS:
1. A CO2 refrigeration system comprising: a
refrigeration circuit in which circulates CO2
refrigerant between at least a first CO2 compression
stage and CO2 supra-compression stage in which the CO2
refrigerant is compressed to at least a supra-compressed
condition, a gas cooling stage in which the supra-
compressed CO2 refrigerant releases heat, a condensation
reservoir in which a portion of the CO2 refrigerant is
accumulated in a liquid state, a pressure-regulating
unit in a line between the gas cooling stage and the
condensation reservoir to cause a pressure drop from the
supra-compressed condition of the CO2 refrigerant in the
gas cooling stage to the condensation reservoir, an
evaporation stage in which the CO2 refrigerant from the
condensation reservoir absorbs heat from a fluid for
refrigeration; and a defrost circuit comprising a
defrost line extending from at least one of the
compression stages to the evaporation stage for
directing compressed CO2 refrigerant to at least one
evaporator of the evaporation stage to absorb heat in
defrosting the at least one evaporator, and further
wherein a pressure-control unit in the defrost line to
reduce a pressure of the CO2 defrost refrigerant when
the defrost line directs CO2 defrost refrigerant from
the CO2 supra-compression stage to the at least one
evaporator for defrost.
2. The CO2 refrigeration system according to
claim 1, wherein the defrost circuit comprises at least
one defrost accumulator connected to the at least one
evaporator for receiving the CO2 defrost refrigerant
exiting the at least one evaporator prior to returning
the CO2 defrost refrigerant to the refrigeration
circuit.
- 26 -

3. The CO2 refrigeration system according to
claim 2, further comprising a line between the defrost
accumulator and the condensation reservoir to return the
CO2 defrost refrigerant to the condensation reservoir.
4. The CO2 refrigeration system according to
claim 1, further comprising a line between the at least
one evaporator, and the first CO2 compression stage, for
returning the CO2 defrost refrigerant to the
refrigeration circuit.
5. The CO2 refrigeration system according to
claim 1, further comprising a suction accumulator
between the compression stages, with a portion of the
CO2 refrigerant exiting the first CO2 compression stage
being directed to the CO2 supra-compression stage via
the suction accumulator.
6. The CO2 refrigeration system according to
claim 5, further comprising a line between the at least
one evaporator, and the suction accumulator between the
compression stages, for returning the CO2 defrost
refrigerant to the refrigeration circuit.
7. The CO2 refrigeration system according to
claim 5, further comprising another suction accumulator
upstream of the first compression stage to separate
liquid and gaseous portions from the CO2 refrigerant
such that gaseous CO2 refrigerant is fed to the first
compression stage.
8. The CO2 refrigeration system according to
claim 7, wherein the other suction accumulator receives
an other portion of the CO2 refrigerant exiting the
-27 -

evaporation stage to then feed said other portion of the
CO2 refrigerant to the first compression stage.
9. The CO2 refrigeration system according to
claim 7, wherein the suction accumulator between
compression stages receives CO2 refrigerant exiting
medium-temperature evaporators of the evaporation stage,
and wherein the other suction accumulator receives CO2
refrigerant exiting low-temperature evaporators of the
evaporation stage.
10. The CO2 refrigeration system according to
claim 1, further comprising a suction accumulator
upstream of the first compression stage to accumulate
CO2 refrigerant being fed to the compression stage, the
suction accumulator connected to the evaporators so as
to receive at least a portion of the CO2 defrost
refrigerant exiting from the at least one evaporator.
11. The CO2 refrigeration system according to
claim 1, further comprising a line between the at least
one evaporator and the condensation reservoir to return
the CO2 defrost refrigerant to the condensation
reservoir.
12. The CO2 refrigeration system according to
claim 1, further comprising a pump between the
condensation reservoir and the evaporation stage to
direct CO2 refrigerant to the evaporation stage.
13. The CO2 refrigeration system according to
claim 1, further comprising a pressure-relief system for
the evaporators of the evaporation stage, the pressure
relief system exhausting CO2 refrigerant from any one of
the evaporators when a pressure of refrigerant in the
refrigeration coil reaching a given threshold.
- 28 -

14. The CO2 refrigeration system according to
claim 7, further comprising a pressure-relief system for
the evaporators of the evaporation stage, the pressure-
relief system exhausting defrost CO2 refrigerant from
any one of the evaporators when a pressure of
refrigerant in the refrigeration coil reaching a given
threshold, the pressure-relief system directing excess-
pressure defrost CO2 refrigerant to any one of the
suction accumulators.
15. The CO2 refrigeration system according to
claim 7, further comprising a pressure-relief valve for
the one of the suction accumulators receiving the
excess-pressure defrost CO2 refrigerant.
16. The CO2 refrigeration system according to
claim 1, further comprising a line between the
evaporation stage and the compression stage to return
the CO2 defrost refrigerant to the compression stage.
17. The CO2 refrigeration system according to
claim 16, further comprising a heat exchanger in said
line to vaporize the CO2 defrost refrigerant returning
to the compression stage.
18. The CO2 refrigeration system according to any
one of claims 1 to 17, wherein the first CO2 compression
stage is a dedicated compressor in parallel to
compressors of the CO2 supra-compression stage.
19. The CO2 refrigeration system according to any
one of claims 1 to 18, wherein the at least one
compression stage comprises at least one compressor
compressing the CO2 refrigerant to a transcritical
condition.
- 29 -


A single figure which represents the drawing illustrating the invention.

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Admin Status

Title Date
(22) Filed 2009-10-23
(41) Open to Public Inspection 2010-04-29
Examination Requested 2011-06-22
(45) Issued 2014-01-28

Maintenance Fee

Description Date Amount
Last Payment 2015-07-28 $200.00
Next Payment if small entity fee 2016-10-24 $100.00
Next Payment if standard fee 2016-10-24 $200.00

Note : If the full payment has not been received on or before the date indicated, a further fee may be required which may be one of the following

  • the reinstatement fee set out in Item 7 of Schedule II of the Patent Rules;
  • the late payment fee set out in Item 22.1 of Schedule II of the Patent Rules; or
  • the additional fee for late payment set out in Items 31 and 32 of Schedule II of the Patent Rules.

Payment History

Fee Type Anniversary Year Due Date Amount Paid Paid Date
Request for Examination $800.00 2011-06-22
Filing $400.00 2011-06-22
Maintenance Fee - Application - New Act 2 2011-10-24 $100.00 2011-06-22
Maintenance Fee - Application - New Act 3 2012-10-23 $100.00 2012-08-13
Maintenance Fee - Application - New Act 4 2013-10-23 $100.00 2013-10-22
Final $300.00 2013-11-13
Maintenance Fee - Patent - New Act 5 2014-10-23 $200.00 2014-07-30
Maintenance Fee - Patent - New Act 6 2015-10-23 $200.00 2015-07-28

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Abstract 2011-06-22 1 29
Claims 2013-03-04 4 148
Claims 2012-10-23 4 147
Claims 2011-06-22 4 152
Cover Page 2014-01-03 2 53
Cover Page 2011-09-02 2 53
Description 2011-06-22 25 1,109
Drawings 2011-06-22 13 258
Prosecution-Amendment 2013-03-04 6 224
Prosecution-Amendment 2012-12-03 3 127
Prosecution-Amendment 2012-10-23 6 242
Prosecution-Amendment 2012-07-26 3 134
Prosecution-Amendment 2012-05-28 2 84
Prosecution-Amendment 2012-02-28 3 95
Prosecution-Amendment 2012-01-20 1 19
Representative Drawing 2014-01-27 1 15
Representative Drawing 2011-09-02 1 15