U.S. patent application number 13/753611 was filed with the patent office on 2014-01-09 for co2 refrigeration system for ice-playing surface.
The applicant listed for this patent is Serge Dube. Invention is credited to Serge Dube.
Application Number | 20140007603 13/753611 |
Document ID | / |
Family ID | 48901211 |
Filed Date | 2014-01-09 |
United States Patent
Application |
20140007603 |
Kind Code |
A1 |
Dube; Serge |
January 9, 2014 |
CO2 REFRIGERATION SYSTEM FOR ICE-PLAYING SURFACE
Abstract
A CO2 refrigeration system comprising a transfer circuit for
heat exchange between a supracompression circuit of CO2
refrigerant, and an evaporation circuit of CO2 refrigerant. A
transfer circuit absorbs heat from the evaporation circuit, and
releases heat to the supracompression circuit. The supracompression
circuit comprises a compression stage in which CO2 refrigerant is
compressed, a cooling stage in which the CO2 refrigerant from the
compression stage releases heat, and a pressure-regulating unit in
a line between the cooling stage and the evaporation heat exchanger
to maintain a pressure differential therebetween. The evaporation
circuit receives CO2 refrigerant having released heat in the
condensation heat exchanger. The evaporation circuit comprises a
condensation reservoir in which CO2 refrigerant is accumulated in a
liquid state, and an evaporation stage in which the CO2 refrigerant
from the condensation reservoir absorbs heat to cool an ice-playing
surface.
Inventors: |
Dube; Serge; (Saint-Zotique,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Dube; Serge |
Saint-Zotique |
|
CA |
|
|
Family ID: |
48901211 |
Appl. No.: |
13/753611 |
Filed: |
January 30, 2013 |
Current U.S.
Class: |
62/235 |
Current CPC
Class: |
F25B 2309/061 20130101;
F25B 6/00 20130101; F25B 9/008 20130101; F25C 3/02 20130101; F25B
25/005 20130101 |
Class at
Publication: |
62/235 |
International
Class: |
F25C 3/02 20060101
F25C003/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 30, 2012 |
CA |
2766361 |
Claims
1.-9. (canceled)
10. A refrigeration system comprising: a compression stage in which
refrigerant is compressed to a higher pressure state; a
condensation stage in which the refrigerant in the higher pressure
state releases heat; a pressure-regulating downstream of the
condensation stage to lower a pressure of the refrigerant having
released heat; and an evaporation stage in which the refrigerant
absorbs heat to cool a fluid; wherein the condensation stage
comprises geothermal gas cooling.
11. The refrigeration system according to claim 10, wherein the
evaporation stage comprises a heat exchanger in which the
refrigerant absorbs heat from another refrigerant.
12. The refrigeration system according to claim 10, wherein the
condensation stage comprises a heat reclaim exchanger by which heat
is reclaimed by another refrigerant for heating purposes.
13. The refrigeration system according to claim 10, wherein the
pressure regulating unit is at least one valve.
14. The refrigeration system according to claim 13, wherein the
valve is an expansion valve.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application claims priority on Canadian Patent
Application No. 2,766,361 filed on Jan. 30, 2012, incorporated
herewith by reference.
FIELD OF THE APPLICATION
[0002] The present application relates to refrigeration systems
used to refrigerate ice-playing surfaces such as a skating rinks,
curling sheets, etc, and more particularly to refrigeration systems
using CO.sub.2 refrigerant.
BACKGROUND OF THE ART
[0003] With the growing concern for global warming, the use of
chlorofluorocarbons (CFCs) and hydrochlorofluoro-carbons (HCFCs) as
refrigerant has been identified as having a negative impact on the
environment. These chemicals have non-negligible ozone-depletion
potential and/or global-warming potential.
[0004] As alternatives to CFCs and HCFCs, ammonia, hydro-carbons
and CO.sub.2 are used as refrigerants. Although ammonia and
hydrocarbons have negligible ozone-depletion potential and
global-warming potential as does CO.sub.2, these refrigerants are
highly flammable and therefore represent a risk to local safety. On
the other hand, CO.sub.2 is environmentally benign and locally
safe.
SUMMARY OF THE APPLICATION
[0005] It is therefore an aim of the present disclosure to provide
a CO.sub.2 refrigeration system for ice-playing surfaces that
addresses issues associated with the prior art.
[0006] Therefore, in accordance with the present application, there
is provided a CO.sub.2 refrigeration system comprising a transfer
circuit for heat exchange between a supracompression circuit of
CO.sub.2 refrigerant, and an evaporation circuit of CO.sub.2
refrigerant; a transfer circuit in which a transfer refrigerant
circulates between a condensation heat exchanger to absorb heat
from the CO.sub.2 refrigerant of the evaporation circuit, and an
evaporation heat exchanger to release heat to the CO.sub.2
refrigerant of the supracompression circuit; the supracompression
circuit comprising a compression stage in which CO.sub.2
refrigerant having absorbed heat in the evaporation heat exchanger
is compressed to at least a supracompression state, a cooling stage
in which the CO.sub.2 refrigerant from the compression stage
releases heat, and a pressure-regulating unit in a line extending
from the cooling stage to the evaporation heat exchanger to
maintain a pressure differential therebetween; the evaporation
circuit receiving CO.sub.2 refrigerant having released heat in the
condensation heat exchanger, the evaporation circuit comprising a
condensation reservoir in which CO.sub.2 refrigerant is accumulated
in a liquid state, and an evaporation stage in which the CO.sub.2
refrigerant from the condensation reservoir absorbs heat to cool an
ice-playing surface, to then return to one of the condensation
reservoir and the condensation exchanger.
BRIEF DESCRIPTION OF DRAWINGS
[0007] FIG. 1 is a block diagram of a CO.sub.2 refrigeration system
for ice-playing surface in accordance with an embodiment of the
present application, with CO.sub.2 refrigerant in a circuit under
the ice-playing surface; and
[0008] FIG. 2 is a block diagram of a CO.sub.2 refrigeration system
for ice-playing surface in accordance with an embodiment of the
present application, with CO.sub.2 refrigerant cooling brine of a
circuit under the ice-playing surface.
DESCRIPTION OF PREFERRED EMBODIMENTS
[0009] Referring to the drawings and more particularly to FIG. 1,
there is illustrated a CO.sub.2 refrigeration system 1 for
ice-playing surface, while FIG. 2 illustrates a CO.sub.2
refrigeration system 2 for ice-playing surface similar to that of
FIG. 1, whereby like reference numerals will refer to like
elements.
[0010] In FIG. 1, the CO.sub.2 refrigeration system 1 has a
CO.sub.2 evaporation circuit 10. The CO.sub.2 evaporation circuit
10 comprises a condensation reservoir 12 accumulating CO.sub.2
refrigerant in a liquid and gaseous state. The CO.sub.2 evaporation
circuit 10 is in a heat-exchange relation with a condensation
circuit that absorbs heat from the CO.sub.2 refrigerant.
[0011] Line 14 directs CO.sub.2 refrigerant from the condensation
reservoir 12 to an evaporation stage, with a flow of CO.sub.2
refrigerant induced by pump and/or an expansion valve(s) as
generally indicated as 15. As is shown in FIG. 1, the CO.sub.2
refrigerant is then fed to the ice-playing surface evaporation
stage 17.
[0012] The ice-playing surface evaporation stage 17 of FIG. 1
consists of a circuit of pipes positioned under the ice-playing
surface, in which the CO.sub.2 refrigerant circulates to absorb
heat from fluid being frozen to form the ice-playing surface, or to
maintain the ice-playing surface frozen.
[0013] CO.sub.2 refrigerant exiting the evaporation stage 17 is
directed to the condensation reservoir 12, by way of line 18.
[0014] The CO.sub.2 evaporation circuit 10 is in a heat-exchange
relation with a transfer circuit 20. The transfer circuit 20 is for
instance of the type in which a transfer refrigerant (e.g.,
alcohol-based such as glycol, water, brine or the like) cycles. A
condensation heat exchanger 21 is in fluid communication with the
condensation reservoir 12, so as to receive CO.sub.2 refrigerant in
a gaseous state, whereby the transfer refrigerant absorbs heat from
the CO.sub.2 refrigerant in the heat exchanger 21. According to an
embodiment, the condensation heat exchanger 21 has a coil that is
positioned inside the condensation reservoir 12.
[0015] The condensation heat exchanger 21 may also receive CO.sub.2
refrigerant directly from line 14, or from line 18. The transfer
circuit 20 is a closed circuit featuring lines 22 and 23 as well as
pump 24 to cycle the transfer refrigerant between the heat
exchanger 21 and an evaporation heat exchanger 31 of a
supra-compression circuit 30. Accordingly, the transfer refrigerant
absorbs heat from the CO.sub.2 refrigerant circulating in the
CO.sub.2 evaporation circuit 10, and releases the heat to the
CO.sub.2 refrigerant circulating in the supra-compression circuit
30.
[0016] In the transfer circuit 20, the condensation refrigerant
circulates between the heat exchanger 21 in which the transfer
refrigerant absorbs heat, and the heat exchanger 31 in which the
transfer refrigerant absorbs heat.
[0017] The supra-compression circuit 30 (i.e., transcritical
circuit if operated at transcritical pressures) is provided to
compress CO.sub.2 refrigerant to a transcritical state, for heating
purposes, or supra-compressed state.
[0018] The heat exchanger 31 vaporizes the CO.sub.2 refrigerant fed
to a supra-compression stage 32. The supra-compression stage 32
features one or more compressors (e.g., Bock.TM., Dorin.TM.), that
compress the CO.sub.2 refrigerant to a supra-compressed or
transcritical state.
[0019] Upon exiting the supra-compression stage 32, the CO.sub.2
refrigerant must be cooled by a cooling stage, embodiments of which
are defined herein.
[0020] In the supra-compressed or transcritical state, the CO.sub.2
refrigerant is used to heat a secondary refrigerant via
heat-reclaim exchanger 34, via line 33. In the heat-reclaim
exchanger 34, the CO.sub.2 refrigerant is in a heat-exchange
relation with a secondary refrigerant circulating in the secondary
refrigerant circuit 35. Alternatively, the heat-reclaim exchanger
34 may be part of a coil of a convection heating unit, etc. In an
embodiment, the heat-reclaim exchanger 34, whether directly or via
the secondary circuit, is used to heat the water used in the
ice-playing surface complex (for meeting the hot water demand for
showers, etc), for heating the surroundings of the ice-playing
surface, or for melting zamboni residue in the ice dump, among
other possibilities.
[0021] The secondary refrigerant is preferably an
environmentally-sound refrigerant, such as water or glycol
(although other refrigerants could be used as well), that is used
as a heat-transfer fluid. Because of the supra-compressed or
transcritical state of the CO.sub.2 refrigerant, the secondary
refrigerant circulating in the circuit 35 reaches a high
temperature. Accordingly, due to the high temperature of the
secondary refrigerant, lines of smaller diameter may be used for
the secondary refrigerant circuit 35. It is pointed out that the
secondary refrigerant circuit 35 may be the largest of the circuits
of the refrigeration system 1 in terms of quantity of refrigerant.
Therefore, the compression of the CO.sub.2 refrigerant into a
transcritical state by the transcritical circuit allows the lines
of the secondary refrigerant circuit 35 to be reduced in terms of
diameter.
[0022] A gas cooling stage 36 is provided in the transcritical
circuit. The gas cooling stage 36 absorbs excess heat from the
CO.sub.2 refrigerant in the transcritical state, in view of
directing the CO.sub.2 refrigerant to the heat exchanger 31.
Although it is illustrated in a parallel relation with the
heat-reclaim exchanger 34, the gas cooling stage 36 may be in
series therewith, or in any other suitable arrangement.
[0023] Moreover, a geothermal gas cooling stage 37 may be provided,
to use the geothermal cool to absorb heat.
[0024] Although not shown, appropriate valves are provided so as to
control the amount of CO.sub.2 refrigerant directed to the gas
cooling stage 36, in view of the heat demand from the heat-reclaim
exchanger 34. Moreover, a bypass line may be provided to bypass the
heat-reclaim exchanger 34, the gas cooling stage 36 and the
geothermal gas cooling 37.
[0025] A CO.sub.2 pressure-regulating valve 39 is provided to
maintain appropriate pressures at the stages 34 and 36, and in the
heat exchanger 31. The CO.sub.2 transcritical pressure-regulating
valve 39 is for instance a Danfoss.TM. valve. Any other suitable
pressure-control device may be used as an alternative to the valve
39, such as any type of valve or loop.
[0026] It is considered to operate the supra-compression circuit
(i.e., supra compression 32) with higher operating pressure.
CO.sub.2 refrigerant has a suitable efficiency at a higher
pressure. More specifically, more heat can be extracted when the
pressure is higher.
[0027] Referring to FIG. 2, the CO.sub.2 refrigeration system is
similar to the CO.sub.2 refrigeration system 1, but comprises an
evaporation exchanger 16, by which the CO.sub.2 refrigerant of the
evaporation circuit 10 absorbs heat from a closed circuit of pipes
of the ice-playing surface refrigeration stage 17. An alternative
refrigerant circulates in the closed circuit of pipes of the
ice-playing surface refrigeration stage 17, such as brine, glycol,
or the like.
[0028] Although not fully illustrated, numerous valves are provided
to control the operation of the CO.sub.2 refrigeration system 1 as
described above. Moreover, a controller ensures that the various
stages of the refrigeration system 1 operate as described, for
instance by having a plurality of sensors places throughout the
refrigeration system 1. Numerous other components may be added to
the refrigeration systems 1 and 2 (e.g., valves, tanks, pumps,
compressors, pressure-relief systems, etc.), to support the
configurations illustrated in FIGS. 1 and 2.
[0029] It is within the ambit of the present invention to cover any
obvious modifications of the embodiments described herein, provided
such modifications fall within the scope of the appended
claims.
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