U.S. patent application number 13/127144 was filed with the patent office on 2011-10-06 for vehicle heating and/or air conditioning method.
This patent application is currently assigned to ARKEMA FRANCE. Invention is credited to Wissam Rached.
Application Number | 20110240254 13/127144 |
Document ID | / |
Family ID | 40551393 |
Filed Date | 2011-10-06 |
United States Patent
Application |
20110240254 |
Kind Code |
A1 |
Rached; Wissam |
October 6, 2011 |
VEHICLE HEATING AND/OR AIR CONDITIONING METHOD
Abstract
The invention relates to a method for the heating and/or air
conditioning of the passenger compartment of an automobile using a
reversible cooling loop in which flows a coolant containing
2,3,3,3-tetrafluoropropene. The method is particularly useful when
outdoor temperature is lower than -15.degree. C. The method can be
used for hybrid automobiles designed for operating alternatively
with a thermal engine and an electric motor.
Inventors: |
Rached; Wissam; (Chaponost,
FR) |
Assignee: |
ARKEMA FRANCE
COLOMBES
FR
|
Family ID: |
40551393 |
Appl. No.: |
13/127144 |
Filed: |
October 28, 2009 |
PCT Filed: |
October 28, 2009 |
PCT NO: |
PCT/FR2009/052075 |
371 Date: |
June 3, 2011 |
Current U.S.
Class: |
165/51 |
Current CPC
Class: |
C09K 2205/126 20130101;
C09K 5/045 20130101; Y02B 30/52 20130101; B60H 1/32284 20190501;
B60H 1/00907 20130101 |
Class at
Publication: |
165/51 |
International
Class: |
F01P 9/00 20060101
F01P009/00 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 3, 2008 |
FR |
08.57454 |
Claims
1. A heating and/or air conditioning system for a passenger
compartment of an automobile having a thermal engine having a
cooling circuit through which an engine coolant flows and/or an
electrical battery comprising a reversible cooling loop in which a
coolant flows, said reversible cooling loop comprising a first heat
exchanger, an expansion valve, a second heat exchanger, a
compressor and means for reversing the direction of flow of the
coolant, characterized in that the coolant comprises
2,3,3,3-tetrafluoropropene.
2. (canceled)
3. The system as claimed in claim 1, characterized in that the
first heat exchanger and the second exchangers are of the
air/coolant type.
4. The system as claimed in claim 1, further characterized in that
the reversible cooling loop is thermally coupled to the cooling
circuit of the thermal engine of said automobile.
5. The system as claimed in claim 1, characterized in that both the
engine coolant and exhaust gases from the thermal engine of the
automobile flow through the first heat exchanger
simultaneously.
6. The system as claimed in claim 1, characterized in that the
reversible cooling loop further comprises a branch having at least
one heat exchanger communicating thermally with a flow of air which
is to be admitted into the thermal engine of the automobile, or
with exhaust gases emitted by the thermal engine of the
automobile.
7. The system as claimed in claim 1, characterized in that the
cooling loop recovers energy from the thermal engine and/or from
the electrical battery.
8. (canceled)
9. A heating and/or air conditioning method for a passenger
compartment of an automobile having a thermal engine having a
thermal engine having a cooling circuit through which an engine
coolant flows and/or an electrical battery, comprising flowing a
coolant through a reversible cooling loop comprising a first heat
exchanger, an expansion valve, a second heat exchanger, a
compressor and means for reversing the direction of flow of the
coolant, characterized in that the coolant comprises
2,3,3,3-tetrafluoropropene.
10. The method as claimed in claim 9, characterized in that the
first and second exchangers are of the air/coolant type.
11. The method as claimed in claim 9, characterized in that the
reversible cooling loop is thermally coupled to the cooling circuit
of the thermal engine.
12. The method as claimed in claim 9, characterized in that the
engine coolant and exhaust gases from the thermal engine of the
automobile flow through the first heat exchanger
simultaneously.
13. The method as claimed in 9, characterized in that the cooling
loop further comprises a branch having at least one heat exchanger
communicating thermally with a flow of air which is to be admitted
into the thermal engine of the automobile or with exhaust gases
emitted by the thermal engine of the automobile.
14. The method as claimed claim 9, characterized in that the
cooling loop recovers energy from the thermal engine and/or from
the electrical battery.
Description
[0001] The present invention relates to a device for heating and/or
air conditioning the passenger compartment of an automobile.
[0002] In automobiles, the thermal engine has a circuit in which
flows a heat transfer fluid which is used for cooling the engine
and also for heating the passenger compartment. For this purpose,
the circuit comprises, notably, a pump and an air heater which
recovers the heat stored by the heat transfer fluid in order to
heat the passenger compartment.
[0003] Additionally, an air conditioning system for cooling the
passenger compartment comprises an evaporator, a compressor, a
condenser, an expansion valve and a fluid, commonly known as a
coolant which can change its state (between liquid and gas). The
compressor, driven directly by the vehicle engine by means of a
belt and pulley, compresses the coolant and sends it back under
high pressure and at high temperature toward the condenser. The
condenser is provided with forced ventilation, causing the
condensation of the gas which arrives in the gaseous state at high
pressure and temperature. The condenser liquefies the gas as a
result of the reduction of the temperature of the air flowing
through it. The evaporator is a heat exchanger which draws heat
from the air which is to be blown into the passenger compartment.
The expansion valve can be used to regulate the inflow of the gas
into the loop by a modification of the passage cross section
depending on the temperature and pressure at the evaporator. Thus
the hot air from outside the vehicle is cooled as it flows through
the evaporator.
[0004] The coolant which is commonly used in automobile air
conditioning is 1,1,1,2-tetrafluoroethane (HFC-134a). Document WO
2008/107623 describes an automobile energy management system
comprising a reversible cooling loop through which a coolant flows,
means for reversing the operating cycle of the cooling loop, which
can move between a cooling mode position and a heat pump mode
position, at least a first source for recovering energy from the
coolant, and at least a second source for evaporating the coolant
after the expansion of said fluid from the liquid to the two-phase
state, the reversal means enabling coolant to flow from the first
recovery source toward at least one evaporation source, when they
are in a position identical to that corresponding to the heat pump
mode.
[0005] However, when HFC-134a is used as the coolant in a system
such as that described in WO 2008/107623, and when the outside
temperature is approximately -15.degree. C., a pressure drop starts
to develop in the evaporator even before the compressor is started.
This pressure drop, which leads to infiltration of air into the
system, promotes corrosion phenomena and the degradation of the
components such as the compressor, exchanger and expansion
valve.
[0006] The object of the present invention is to prevent the air
from penetrating into the evaporator of the cooling loop when the
compressor is started, and/or to improve the efficiency of the
cooling loop.
[0007] The present invention therefore proposes a heating and/or
air conditioning method for a passenger compartment of an
automobile, using a reversible cooling loop, in which a coolant
flows, comprising a first heat exchanger, an expansion valve, a
second heat exchanger, a compressor and means for reversing the
direction of flow of the coolant, characterized in that the coolant
comprises 2,3,3,3-tetrafluoropropene.
[0008] The means for reversing the direction of flow of the coolant
in the cooling loop in order to reverse the operating cycle of the
loop can be a four-way valve.
[0009] In addition to the 2,3,3,3-tetrafluoropropene, the coolant
can comprise saturated or unsaturated hydrofluorocarbons.
[0010] Examples of saturated hydrofluorocarbons which may be
mentioned are, notably, difluoromethane, difluoro-ethane,
tetrafluoroethane and pentafluoroethane.
[0011] Examples of unsaturated hydrofluorocarbons which may be
mentioned are, notably, 1,3,3,3-tetrafluoropropene,
trifluoropropenes such as 3,3,3-trifluoropropene, and
monochlorotrifluoropropenes such as 1-chloro,3,3,3-trifluoropropene
and 2-chloro,3,3,3-trifluoropropene.
[0012] The following compositions may be suitable for use as
coolants in the method according to the present invention: [0013]
80% to 98% by weight of 2,3,3,3-tetrafluoropropene and 2% to 20% by
weight of difluoromethane, [0014] 40% to 95% by weight of
2,3,3,3-tetrafluoropropene and 5% to 60% by weight of
1,1,1,2-tetrafluoroethane, [0015] 90% to 98% by weight of
2,3,3,3-tetrafluoropropene and 2% to 10% by weight of
difluoroethane, [0016] 90% to 98% by weight of
2,3,3,3-tetrafluoropropene and 2% to 10% by weight of
pentafluoroethane.
[0017] The following compositions are especially suitable for use
as coolants: [0018] 90% to 98% by weight of
2,3,3,3-tetrafluoropropene and 2% to 10% by weight of
difluoromethane, [0019] 90% to 95% by weight of
2,3,3,3-tetrafluoropropene and 5% to 10% by weight of
1,1,1,2-tetrafluoroethane, [0020] 95% to 98% by weight of
2,3,3,3-tetrafluoropropene and 2% to 5% by weight of
difluoroethane, [0021] 95% to 98% by weight of
2,3,3,3-tetrafluoropropene and 2% to 5% by weight of
pentafluoroethane.
[0022] A composition which essentially contains
2,3,3,3-tetrafluoropropene is particularly preferred.
[0023] The coolant can also comprise stabilizers of the
2,3,3,3-tetrafluoropropene. Examples of stabilizer which may be
mentioned are, notably, 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 which may be
fluorinated or perfluorinated or alkenyl or aromatic) such as
n-butyl glycidyl ethers, hexanediol diglycidyl ethers, allyl
glycidyl ether, butylphenyl glycidyl ethers, phosphites,
phosphates, phosphonates, thiols and lactones.
[0024] Depending on the operating mode of the loop, which may be
the cooling or heat pump mode, the first heat exchanger can act as
an evaporator or as an energy recovery unit. The same is true of
the second heat exchanger. In cooling mode, the second exchanger
can be used for cooling the air flow which is to be blown into the
passenger compartment of the automobile. In heat pump mode, the
second exchanger can be used to heat the air flow intended for the
passenger compartment of the automobile. The first and second heat
exchangers are of the air/coolant type.
[0025] In the method according to the present invention, the
cooling loop can be thermally coupled through the heat exchangers
to the entire cooling circuit. Thus the loop can comprise at least
one heat exchanger through which the coolant and a heat transfer
fluid flow simultaneously, the heat transfer fluid being, notably,
the air or water of the thermal engine cooling circuit.
[0026] In a variant of the method, both the coolant and the exhaust
gases from the thermal engine of the automobile flow through the
first heat exchanger simultaneously; these fluids can communicate
thermally by means of a heat transfer fluid circuit.
[0027] In the method according to the present invention, the
cooling loop can include a branch having at least one heat
exchanger communicating thermally with a flow of air which is to be
admitted into the thermal engine of the automobile, or with exhaust
gases emitted by the thermal engine of the automobile.
[0028] The method according to the present invention is
particularly suitable when the outside temperature is below
-15.degree. C., or preferably below -20.degree. C.
[0029] The method according to the present invention is equally
suitable for hybrid automobiles designed to operate alternatively
with a thermal engine and an electric motor. It can be used to
provide the best management of the energy contributions according
to the climatic conditions (hot or cold) for both the passenger
compartment and the battery, and notably to supply heat or cold to
the battery through a heat transfer fluid circuit.
[0030] The reversible cooling loop, in which the coolant containing
2,3,3,3-tetrafluoropropene flows, installed in automobiles is
particularly suitable for the recovery of energy from the thermal
engine and/or from the electrical battery, for use in heating the
passenger compartment and for heating the thermal engine during a
cold start phase. When this reversible cooling loop comprises a
pump, it can operate in Rankine mode (that is to say, the
compressor acts as a turbine) to exploit the thermal energy
produced by the thermal engine and subsequently conveyed by the
coolant, after heat transfer.
[0031] The invention also proposes a device comprising the cooling
loop as described above.
[0032] In a first embodiment of the invention, illustrated
schematically in FIG. 1, the cooling loop (16) comprises a first
heat exchanger (13), an expansion valve (14), a second heat
exchanger (15), a compressor (11) and a four-way valve (12). The
first and second heat exchangers are of the air/coolant type. The
coolant of the loop (16) and the air flow supplied by a fan pass
through the first heat exchanger (13). Some or all of this air flow
also passes through a heat exchanger of the engine cooling circuit
(not shown in the drawing). In the same way, an air flow supplied
by a fan passes through the second exchanger (15). Some or all of
this air flow also passes through another heat exchanger of the
engine cooling circuit (not shown in the drawing). The direction of
flow of the air is a function of the operating mode of the loop
(16) and of the requirements of the thermal engine. Thus, when the
thermal engine is in stationary mode and the loop (16) is in heat
pump mode, the air can be heated by the exchanger of the thermal
engine cooling circuit, and can then be blown on to the exchanger
(13) to accelerate the evaporation of the fluid of the loop (16)
and thereby improve the performance of this loop. The exchangers of
the cooling circuit can be activated by means of valves according
to the requirements of the thermal engine (for heating the air
entering the engine or for exploiting the energy produced by this
engine).
[0033] In cooling mode, the coolant propelled by the compressor
(11) flows through the valve (12) and then through the exchanger
(13) which acts as a condenser (that is to say, it releases heat to
the outside), and subsequently through the expansion valve (14) and
then through the exchanger (15) which acts as an evaporator for
cooling the air flow which is to be blown into the passenger
compartment of the automobile.
[0034] In heat pump mode, the direction of flow of the coolant is
reversed by means of the valve (12). The heat exchanger (15) acts
as a condenser, while the exchanger (13) acts as an evaporator. The
heat exchanger (15) can then be used to heat the air flow intended
for the passenger compartment of the automobile.
[0035] In a second embodiment of the invention, shown schematically
in FIG. 2, the cooling loop (26) comprises a first heat exchanger
(23), an expansion valve (24), a second heat exchanger (25), a
compressor (21), a four-way valve (22) and a branch (d3) connected
at one end to the outlet of the exchanger (23) and at the other end
to the outlet of the exchanger (25), with respect to the flow of
the fluid in cooling mode. This branch comprises a heat exchanger
(d1), through which an air flow or a flow of exhaust gas to be
admitted into the thermal engine passes, and an expansion valve
(d2). The first and second heat exchangers (23 and 25) are of the
air/coolant type. The coolant of the loop (26) and the air flow
supplied by a fan pass through the first heat exchanger (23). Some
or all of this air flow also passes through a heat exchanger of the
engine cooling circuit (not shown in the drawing). In the same way,
an air flow supplied by a fan passes through the second exchanger
(25). Some or all of this air flow also passes through another heat
exchanger of the engine cooling circuit (not shown in the drawing).
The direction of flow of the air is a function of the operating
mode of the loop (26) and of the requirements of the thermal
engine. By way of example, when the thermal engine is in stationary
mode and the loop (26) is in heat pump mode, the air can be heated
by the exchanger of the thermal engine cooling circuit, and can
then be blown on to the exchanger (23) to accelerate the
evaporation of the fluid of the loop (26) and thereby improve the
performance of this loop.
[0036] The exchangers of the cooling circuit can be activated by
means of valves according to the requirements of the thermal engine
(for heating the air entering the engine or for exploiting the
energy produced by this engine).
[0037] The heat exchanger (d1) can also be activated according to
the energy requirements in either cooling or heat pump mode. Check
valves can be fitted in the branch (d3) to activate or disable this
branch.
[0038] A flow of air supplied by a fan passes through the exchanger
(d1). The same air flow can pass through another heat exchanger of
the engine cooling circuit and also through other exchangers placed
in the exhaust gas circuit, on the air intake of the engine, or on
the battery in a hybrid automobile.
[0039] In a third embodiment of the invention, illustrated
schematically in FIG. 3, the cooling loop (36) comprises a first
heat exchanger (33), an expansion valve (34), a second heat
exchanger (35), a compressor (31) and a four-way valve (32). The
first and second heat exchangers (33 and 35) are of the air/coolant
type. The operation of the exchangers (33 and 35) is identical to
that of the first embodiment shown in FIG. 1. Two fluid/liquid
exchangers (38 and 37) are fitted both in the cooling loop circuit
(36) and in the thermal engine cooling circuit or in a secondary
glycol-water circuit. The fitting of the fluid/liquid exchangers
without the use of an intermediate gaseous fluid (air) flowing
through them contributes to an improvement of the heat exchange
with respect to air/fluid exchangers. In a fourth embodiment of the
invention, illustrated schematically in FIG. 4, the cooling loop
(46) comprises a first heat exchanger set (43 and 48), an expansion
valve (44), a second heat exchanger set (45 and 47), a compressor
(41) and a four-way valve (42). A branch (d1) having one end
connected to the outlet of the exchanger (43) and the other end
connected to the outlet of the exchanger (47), with respect to the
flow of the fluid in cooling mode. This branch comprises a heat
exchanger (d1), through which an air flow or a flow of exhaust gas
to be admitted into the thermal engine passes, and an expansion
valve (d2). The operation of this branch is identical to that of
the second embodiment shown in FIG. 2.
[0040] The heat exchangers (43 and 45) are of the air/coolant type
and the exchangers (48 and 47) are of the liquid/coolant type. The
operation of these exchangers is identical to that of the third
embodiment shown in FIG. 3.
EXPERIMENTAL SECTION
[0041] Simulations of the performance of the coolant in the heat
pump operating conditions in vehicles are given below, for a
condenser temperature of 30.degree. C. Condensation temperature:
+30.degree. C. (T cond)
[0042] Temperature at the compressor inlet: +5.degree. C. (Te
comp)
[0043] Evap P is the pressure at the evaporator.
[0044] Cond P is the pressure at the condenser.
[0045] T outlet comp is the temperature at the compressor
outlet.
[0046] Rate: the compression rate is the ratio of the high pressure
to the low pressure.
[0047] COP: this is the coefficient of performance and is defined,
in the case of a heat pump, as the useful thermal power supplied by
the system divided by the power received or consumed by the
system.
[0048] CAP: this is the cubic capacity, which is the heating
capacity per unit of volume (kJ/m.sup.3).
[0049] % CAP or COP is the ratio of the value of the CAP or COP of
2,3,3,3-tetrafluoropropene (HFO-1234yf) to that of HFC-134a.
[0050] Isentropic efficiency of the compressor: this is the ratio
between the real energy transmitted to the fluid and the isentropic
energy.
[0051] The isentropic efficiency of the compressor is expressed as
a function of the compression rate. (FIG. 5)
.eta.=a+b.tau.+c.tau..sup.2+d.tau..sup.3+e.tau..sup.4
.eta.=isentropic efficiency .tau.: compression rate a, b, c and e:
constants
[0052] The values of the constants a, b, c, d and e are determined
from a standard efficiency curve, found in "Handbook of air
conditioning and refrigeration", by Shan K. Wang.
[0053] For HFC-134a, the COP and the pressure at the evaporator
decrease with the evaporation temperature.
TABLE-US-00001 Temp evap P cond P Rate T outlet CAP Isentrop. evap
(.degree. C.) (kPa) (kPa) (p/p) comp (kJ/m.sup.3) eff. COPc
HFC-134a -35.00 66.70 768.33 11.52 82.61 679.70 0.62 2.32 -30.00
84.92 768.33 9.05 75.31 841.71 0.68 2.82 -25.00 106.89 768.33 7.19
68.35 1032.37 0.75 3.39 -20.00 133.14 768.33 5.77 61.72 1255.21
0.79 4.01
[0054] For HFO-1234yf in the same conditions, we find:
TABLE-US-00002 Temp evap P cond P Rate T outlet CAP Isentrop. evap
(.degree. C.) (kPa) (kPa) (p/p) comp (kJ/m.sup.3) eff. COPc % cap %
COP HFO-1234yf -35.00 77.05 772.09 10.02 70.15 707.00 0.66 2.43 104
104 -30.00 97.01 772.09 7.96 64.10 865.60 0.72 2.91 103 103 -25.00
120.73 772.09 6.40 58.36 1049.51 0.77 3.45 102 102 -20.00 148.64
772.09 5.19 52.88 1261.40 0.81 4.01 100 100
[0055] The evaporator pressure with HFO-1234yf is higher than with
HFC-134a, thus helping to limit the infiltration of air into the
system when the system operates at a very low temperature.
[0056] For a given compressor operating at very low temperature,
the performance of HFO-1234yf is better than that of HFC 134a. In
heating mode and when the condensation temperature is 30.degree.
C., the use of HFO-1234yf yields better efficiency at the
compressor, better COP and better capacity.
* * * * *