U.S. patent application number 13/393626 was filed with the patent office on 2012-07-05 for heat transfer method.
This patent application is currently assigned to Arkema France. Invention is credited to Wissam Rached.
Application Number | 20120167615 13/393626 |
Document ID | / |
Family ID | 42091497 |
Filed Date | 2012-07-05 |
United States Patent
Application |
20120167615 |
Kind Code |
A1 |
Rached; Wissam |
July 5, 2012 |
HEAT TRANSFER METHOD
Abstract
The invention relates to a heat transfer method using ternary
compositions containing 2,3,3,3-tetrafluoropropene,
1,1-difluoroethane and difluoromethane, said compositions being
especially interesting as a heat transfer fluid in compression
refrigeration systems comprising exchangers operation in
counterflow mode or in split flow mode with counterflow
tendency.
Inventors: |
Rached; Wissam; (Chaponost,
FR) |
Assignee: |
Arkema France
Colombes
FR
|
Family ID: |
42091497 |
Appl. No.: |
13/393626 |
Filed: |
August 18, 2010 |
PCT Filed: |
August 18, 2010 |
PCT NO: |
PCT/FR2010/051728 |
371 Date: |
March 1, 2012 |
Current U.S.
Class: |
62/468 ;
62/498 |
Current CPC
Class: |
C09K 5/045 20130101;
F25B 31/002 20130101; F25B 13/00 20130101; C09K 2205/126 20130101;
C09K 2205/22 20130101; F25B 9/006 20130101 |
Class at
Publication: |
62/468 ;
62/498 |
International
Class: |
F25B 1/00 20060101
F25B001/00; F25B 41/00 20060101 F25B041/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 11, 2009 |
FR |
09.56246 |
Claims
1. (canceled)
2. The heat transfer system as claimed in claim 6, characterized in
that the ternary composition consists essentially of from 20 to 80
wt. % of 2,3,3,3-tetrafluoropropene and from 15 to 40 wt. % of
difluoromethane and from 5 to 40 wt. % of difluoroethane.
3. The heat transfer system as claimed in claim 6, characterized in
that the ternary composition consists essentially of from 20 to 70
wt. % of 2,3,3,3-tetrafluoropropene and from 20 to 40 wt. % of
difluoromethane and from 10 to 40 wt. % of difluoroethane.
4. (canceled)
5. The heat transfer system as claimed in claim 6, characterized in
that the ternary composition is stabilized.
6. A heat transfer system comprising a compression-type
refrigeration system with exchangers operating in countercurrent
mode or in crossed-current mode with countercurrent tendency and a
refrigerant comprising a ternary composition of
2,3,3,3-tetrafluoropropene, 1,1-difluoroethane and
difluoromethane.
7. The heat transfer system as claimed in claim 6, characterized in
that the ternary composition consists essentially of from 35 to 70
wt. % of 2,3,3,3-tetrafluoropropene and from 20 to 25 wt. % of
difluoromethane and from 10 to 40 wt. % of difluoroethane.
8. The heat transfer system as claimed in claim 6, characterized in
that further comprises a lubricant.
Description
[0001] The present invention relates to the use of ternary
compositions of 2,3,3,3-tetrafluoropropene as heat transfer
fluids.
[0002] The problems posed by substances with ozone depletion
potential (ODP) were discussed in Montreal, where the protocol was
signed requiring a reduction of the production and use of
chlorofluorocarbons (CFCs). Amendments were made to this protocol,
which imposed abandonment of CFCs, and extended the regulations to
cover other products, including hydrochloro-fluorocarbons
(HCFCs).
[0003] The refrigeration and air conditioning industry has made a
considerable investment in the replacement of these refrigerants,
which is what led to the marketing of hydrofluorocarbons
(HFCs).
[0004] The (hydro)chlorofluorocarbons used as expanding agents or
solvents have also been replaced with HFCs.
[0005] In the automobile industry, the systems for air conditioning
of vehicles marketed in many countries have changed over from a
chlorofluorocarbon refrigerant (CFC-12) to a hydrofluorocarbon
refrigerant (1,1,1,2-tetrafluoroethane: HFC-134a), which is less
harmful to the ozone layer. However, with regard to the objectives
established by the Kyoto protocol, HFC-134a (GWP=1300) is
considered to have a high warming power. A fluid's contribution to
the greenhouse effect is quantified by a criterion, GWP (Global
Warming Potential), which summarizes the warming power, taking a
reference value of 1 for carbon dioxide.
[0006] Carbon dioxide, being nontoxic, nonflammable and having a
very low GWP, has been proposed as refrigerant for air conditioning
systems, replacing HFC-134a. However, the use of carbon dioxide has
several drawbacks, notably connected with the very high pressure
for application as refrigerant in the existing equipment and
technologies.
[0007] Moreover, the mixture R-404A consisting of 44 wt. % of
pentafluoroethane, 52 wt. % of trifluoroethane and 4 wt. % of
HFC-134a is widely used as fluid for refrigeration of large areas
(supermarkets) and in refrigerated transport. However, this mixture
has a GWP of 3900. The mixture R-4070, consisting of 52 wt. % of
HFC-134a, 25 wt. % of pentafluoroethane and 23 wt. % of
difluoromethane, is used as heat transfer fluid in air conditioning
and heat pumps. However, this mixture has a GWP of 1800.
[0008] Document JP 4110388 describes the use of hydrofluoropropenes
of formula C.sub.3H.sub.mF.sub.n, with m, representing an integer
between 1 and 5 inclusive and m+n=6, as heat transfer fluids, in
particular tetrafluoropropene and trifluoropropene.
[0009] Document WO2004/037913 discloses the use of compositions
comprising at least one fluoroalkene having three or four carbon
atoms, notably pentafluoropropene and tetrafluoropropene,
preferably having a GWP of at most 150, as heat transfer
fluids.
[0010] Document WO 2005/105947 teaches the addition to
tetrafluoropropene, preferably 1,3,3,3-tetrafluoropropene, of a
co-blowing agent such as difluoromethane, pentafluoroethane,
tetrafluoroethane, difluoroethane, heptafluoropropane,
hexafluoropropane, pentafluoropropane, pentafluorobutane, water and
carbon dioxide.
[0011] Document WO 2006/094303 discloses an azeotropic composition
containing 7.4 wt. % of 2,3,3,3-tetrafluoropropene (1234yf) and
92.6 wt. % of difluoromethane (HFC-32). This document also
discloses an azeotropic composition containing 91 wt. % of
2,3,3,3-tetrafluoropropene and 9 wt. % of difluoroethane
(HFC-152a).
[0012] A heat exchanger is a device enabling thermal energy to be
transferred from one fluid to another, without mixing them. The
thermal flux passes through the exchange surface that separates the
fluids. This method is most often used for cooling or heating a
liquid or a gas that it is impossible to cool or heat directly.
[0013] In compression systems, heat exchange between the
refrigerant and the heat sources is effected via heat-transfer
fluids. These heat-transfer fluids are in the gaseous state (the
air in air conditioning and direct-expansion refrigeration), liquid
(the water in domestic heat pumps, glycol solution) or
two-phase.
[0014] There are various transfer modes: [0015] the two fluids are
arranged in parallel and go in the same sense: co-current mode
(antimethodical); [0016] the two fluids are arranged in parallel
but go in the opposite sense: countercurrent mode (methodical);
[0017] the two fluids are positioned perpendicularly:
crossed-current mode. Crossed-current can have a co-current or
countercurrent tendency; [0018] one of the two fluids makes a
U-turn in a wider pipeline, which the second fluid passes through.
This configuration is comparable to a co-current exchanger over
half its length, and to a countercurrent exchanger for the other
half: pin-head mode.
[0019] The applicant has now discovered that ternary compositions
of 2,3,3,3-tetrafluoropropene, 1,1-difluoroethane and
difluoromethane are particularly interesting as heat transfer fluid
in compression-type refrigeration systems with exchangers operating
in countercurrent mode or in crossed-current mode with
countercurrent tendency.
[0020] Thus, these compositions can be used as heat transfer fluid
in heat pumps, optionally reversible, in air conditioning,
industrial air conditioning (paper, rooms for servers), in mobile
domestic air conditioning, in domestic refrigeration and freezing,
in low- and medium-temperature refrigeration and refrigeration of
refrigerated vehicles employing compression systems with exchangers
in countercurrent mode or in crossed-current mode with
countercurrent tendency.
[0021] These compositions have both a zero ODP and a GWP below that
of existing heat transfer fluids such as R-404A or R-407C.
Moreover, their performance (COP: coefficient of performance,
defined as the useful power delivered by the system over the power
input or consumption of the system; and CAP: volumetric capacity
(kJ/m.sup.3)) are greater than those of existing heat transfer
fluids such as R-404A or R-407C.
[0022] The compositions used as heat transfer fluid in the present
invention have a critical temperature above 93.degree. C. (the
critical temperature of R-404A is 72.degree. C.). These
compositions can be used in heat pumps to supply heat at
temperatures up to 65.degree. C. but also at higher temperatures up
to 90.degree. C. (temperature range where R-404A cannot be
used).
[0023] The compositions used as heat transfer fluid in the present
invention have pressures at the condenser lower than the pressures
of R-404A as well as lower compression ratios. These compositions
can use the same compressor technology used by R-404A. The
compositions used as heat transfer fluid in the present invention
have saturated vapor densities less than the saturated vapor
density of R-404A. The volumetric capacities given by these
compositions are equivalent to or greater than the volumetric
capacity of R404A (between 97 and 110%). Owing to these properties,
these compositions operate with smaller pipeline diameters and
therefore less head loss in the vapor pipelines, which increases
the performance of the installations.
[0024] The present invention therefore relates to the use of
ternary compositions of 2,3,3,3-tetrafluoropropene,
1,1-difluoroethane and difluoromethane that are particularly
interesting as heat transfer fluid in compression-type
refrigeration systems with exchangers operating in countercurrent
mode or in crossed-current mode with countercurrent tendency.
[0025] Preferably, the compositions used in the present invention
contain essentially from 20 to 80 wt. % of
2,3,3,3-tetrafluoropropene and from 15 to 40 wt. % of
difluoromethane and from 5 to 40 wt. % of 1,1-difluoroethane.
[0026] Advantageously, the compositions used contain essentially
from 20 to 70 wt. % of 2,3,3,3-tetrafluoropropene and from 20 to 40
wt. % of difluoromethane and from 10 to 40 wt. % of
difluoroethane.
[0027] The compositions that are particularly preferred contain
essentially from 35 to 70 wt. % of 2,3,3,3-tetrafluoropropene from
20 to 25 wt. % of difluoromethane and from 10 to 40 wt. % of
1,1-difluoroethane.
[0028] The compositions used in the present invention can be
stabilized. The stabilizer represents at most 5 wt. % relative to
the total composition.
[0029] As stabilizers, we may notably mention nitromethane,
ascorbic acid, terephthalic acid, azoles such as tolutriazole or
benzotriazole, phenolic compounds such as tocopherol, hydroquinone,
t-butyl hydroquinone, 2,6-di-tert-butyl-4-methylphenol, epoxides
(alkyl optionally fluorinated or perfluorinated or alkenyl or
aromatic epoxides) such as n-butyl glycidyl ether, hexanediol
diglycidyl ether, allyl glycidyl ether, butylphenylglycidyl ether,
phosphites, phosphates, phosphonates, thiols and lactones.
[0030] Another object of the present invention relates to a method
of heat transfer in which ternary compositions of
2,3,3,3-tetrafluoropropene, 1,1-difluoroethane and difluoromethane
are used, which are particularly interesting as heat transfer fluid
in compression-type refrigeration systems with exchangers operating
in countercurrent mode or in crossed-current mode with
countercurrent tendency.
[0031] The method according to the present invention can be
employed in the presence of lubricants such as mineral oil,
alkylbenzene, polyalkylene glycol and polyvinyl ether.
[0032] The compositions used in the present invention are suitable
for replacing R-404A in refrigeration and/or R-407C in air
conditioning and heat pumps in existing installations.
EXPERIMENTAL SECTION
Tools for Calculation
[0033] The RK-Soave equation is used for calculating the densities,
enthalpies, entropies and data for liquid-vapor equilibrium of the
mixtures. To use this equation it is necessary to know the
properties of the pure substances used in the mixtures in question
as well as the coefficients of interaction for each binary mixture.
The data required for each pure substance are: boiling point,
critical temperature and pressure, curve of pressure as a function
of temperature from the boiling point up to the critical point,
saturated liquid density and saturated vapor density as a function
of temperature.
HFC-32, HFC-152a:
[0034] The data for these products are published in ASHRAE Handbook
2005 chapter 20, and are also available using Refrop (software
developed by NIST for calculating the properties of
refrigerants).
HFO-1234yf:
[0035] The data for the temperature-pressure curve of HFO-1234yf
are measured by the static method. The critical temperature and
pressure are measured with a C80 calorimeter marketed by Setaram.
The densities at saturation as a function of temperature are
measured by the technology of the vibrating-tube densimeter
developed by the laboratories of the Ecole des Mines de Paris.
Coefficient of Interaction of the Binary Mixtures
[0036] The RK-Soave equation uses coefficients of binary
interaction for representing the behavior of the products in
mixtures. The coefficients are calculated as a function of
experimental data for liquid-vapor equilibrium.
[0037] The technique used for the measurements of liquid-vapor
equilibrium is the static analytical cell method. The equilibrium
cell comprises a sapphire tube and is equipped with two ROLSITM
electromagnetic samplers. It is immersed in a cryothermostat bath
(HUBER HS40). Magnetic stirring driven by a field rotating at
variable speed is used to accelerate the attainment of equilibrium.
The samples are analyzed by gas chromatography (HP5890 series II)
using a catharometer (TCD).
HFC-32/HFO-1234yf, HFC-152a/HFO-1234yf:
[0038] The measurements of liquid-vapor equilibrium on the
HFC-32/HFO-1234yf binary mixture are performed for the following
isotherms: -10.degree. C., 30.degree. C. and 70.degree. C.
[0039] The measurements of liquid-vapor equilibrium on the
HFC-152a/HFO-1234yf binary mixture are performed for the following
isotherms: 10.degree. C.
HFC-32/HF0-152a:
[0040] The data for liquid-vapor equilibrium for the
HFC-152a/HFC-32 binary mixture are available using Refprop. Two
isotherms (-20.degree. C. and 20.degree. C.) and two isobars (1 bar
and 25 bar) are used for calculating the coefficients of
interaction for this binary mixture.
Compression System
[0041] Consider a compression system equipped with an evaporator
and countercurrent condenser, a screw compressor and a pressure
reducing valve.
[0042] The system operates with 15.degree. C. of superheating and
5.degree. C. of supercooling. The minimum temperature difference
between secondary fluid and the refrigerant is considered to be of
the order of 5.degree. C.
[0043] The isentropic efficiency of the compressors is a function
of the compression ratio. This efficiency is calculated from the
following equation:
.eta. isen = a - b ( .tau. - c ) 2 - d .tau. - e . ( 1 )
##EQU00001##
[0044] For a screw compressor, constants a, b, c, d and e in
equation (1) of isentropic efficiency are calculated using the
standard data published in the Handbook "Handbook of air
conditioning and refrigeration, page 11.52". The % CAP is the
percentage of the ratio of the volumetric capacity supplied by each
product to the capacity of R-404A.
[0045] The coefficient of performance (COP) is defined as the
useful power delivered by the system over the power input or
consumption of the system.
[0046] The Lorenz coefficient of performance (COPLorenz) is a
reference coefficient of performance. It is a function of
temperature and is used for comparing the COPs of different
fluids.
[0047] The Lorenz coefficient of performance is defined as
follows:
(The temperatures T are in K)
T.sub.mean.sup.condenser=T.sub.inlet.sup.condenser-T.sub.outlet.sup.cond-
enser (2)
T.sub.mean.sup.evaporator=T.sub.outlet.sup.evaporator-T.sub.inlet.sup.ev-
aporator (3)
[0048] The Lorenz COP in the case of air conditioning and
refrigeration is:
COPlorenz = T mean evaporator T mean condenser - T mean evaporator
( 4 ) ##EQU00002##
[0049] The Lorenz COP in the case of heating is:
COPlorenz = T mean condenser T mean condenser - T mean evaporator (
5 ) ##EQU00003##
[0050] For each composition, the coefficient of performance of the
Lorenz cycle is calculated as a function of the corresponding
temperatures.
[0051] % COP/COPLorenz is the ratio of the COP of the system to the
COP of the corresponding Lorenz cycle.
Results in Heating Mode
[0052] In heating mode, the compression system operates between an
inlet temperature of the refrigerant at the evaporator of
-5.degree. C. and an inlet temperature of the refrigerant at the
condenser of 50.degree. C. The system supplies heat at 45.degree.
C.
[0053] The performance of the compositions according to the
invention in the operating conditions in heating mode are given in
table 1. The values of the constituents (HFO-1234yf, HFC-32,
HFC-152a) for each composition are given as percentage by
weight.
TABLE-US-00001 TABLE 1 Temp outlet Temp outlet T outlet evap P cond
P Ratio efficiency % COP/ evap (.degree. C.) comp (.degree. C.)
cond (.degree. C.) (bar) (bar) (w/w) Shift comp % CAP COPLorenz
R404A -5 77 50 5.2 23.0 4.4 0.38 79.7 100 57.7 HFO- HFC- HFC-
1234yf 32 152a 70 20 10 0 81 43 4.2 17.3 4.1 4.86 80.7 97 65.8 60
25 15 0 85 43 4.4 18.1 4.1 5.02 80.7 104 65.9 50 25 25 0 88 43 4.2
17.7 4.2 4.98 80.4 102 66.6 35 25 40 0 92 43 3.9 16.9 4.3 5.18 80.1
100 67.6
Results for Cooling, Mode or Air Conditioning
[0054] In cooling mode, the compression system operates between an
inlet temperature of the refrigerant at the evaporator of
-5.degree. C. and an inlet temperature of the refrigerant at the
condenser of 50.degree. C. The system supplies cold at 0.degree. C.
0.10 The performance of the compositions according to the invention
in the operating conditions in cooling mode is shown in table 2.
The values of the constituents (HFO-1234yf, HFC-32, HFC-152a) for
each composition are given as percentage by weight.
TABLE-US-00002 TABLE 2 Temp outlet Temp outlet T outlet evap P cond
P Ratio efficiency % COP/ evap (.degree. C.) comp (.degree. C.)
cond (.degree. C.) (BAR) (bar) (w/w) Shift comp % CAP COPLorenz
R404A -5 77 50 5.2 23.0 4.4 0.38 79.7 100 47.9 HFO- HFC- 1234yf
HFC-32 152a 70 20 10 0 81 43 4.2 17.3 4.1 4.86 80.7 105 57.8 65 20
15 0 82 43 4.1 17.1 4.2 4.68 80.6 104 58.3 60 25 15 0 85 43 4.4
18.1 4.1 5.02 80.7 113 58.2 55 20 25 0 85 43 3.9 16.7 4.2 4.52 80.3
104 59.0 50 25 25 0 88 43 4.2 17.7 4.2 4.98 80.4 112 59.2 40 20 40
0 89 43 3.7 16.1 4.4 4.58 80.0 103 60.3 35 25 40 0 92 43 3.9 16.9
4.3 5.18 80.1 110 60.5
* * * * *