U.S. patent application number 15/037750 was filed with the patent office on 2016-09-22 for single circuit refrigeration appliance.
The applicant listed for this patent is BSH HAUSGERATE GMBH. Invention is credited to NIELS LIENGAARD.
Application Number | 20160273822 15/037750 |
Document ID | / |
Family ID | 51871024 |
Filed Date | 2016-09-22 |
United States Patent
Application |
20160273822 |
Kind Code |
A1 |
LIENGAARD; NIELS |
September 22, 2016 |
SINGLE CIRCUIT REFRIGERATION APPLIANCE
Abstract
A single-circuit refrigeration appliance includes a thermally
insulated housing and a refrigerant circuit in which the following
are connected in series between a pressure connection and a suction
connection of a compressor: a condenser, a first throttle point, a
first evaporator that cools a first storage compartment in the
housing, a second throttle point, and a second evaporator that
cools a second storage compartment in the housing. The second
throttle point has an adjustable volume flow rate.
Inventors: |
LIENGAARD; NIELS; (ULM,
DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
BSH HAUSGERATE GMBH |
Munchen |
|
DE |
|
|
Family ID: |
51871024 |
Appl. No.: |
15/037750 |
Filed: |
November 6, 2014 |
PCT Filed: |
November 6, 2014 |
PCT NO: |
PCT/EP2014/073964 |
371 Date: |
May 19, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
Y02B 30/70 20130101;
F25B 5/04 20130101; F25B 41/062 20130101; F25B 2600/0253 20130101;
Y02B 40/00 20130101; Y02B 40/32 20130101; F25D 2700/123 20130101;
F25D 2700/12 20130101; F25B 2341/0662 20130101; Y02B 30/741
20130101; F25B 41/067 20130101; F25D 11/022 20130101 |
International
Class: |
F25D 11/02 20060101
F25D011/02; F25B 41/06 20060101 F25B041/06; F25B 5/04 20060101
F25B005/04 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 20, 2013 |
DE |
10 2013 223 737.5 |
Claims
1-9. (canceled)
10. A single-circuit refrigeration appliance, comprising: a
thermally insulated housing; a first storage compartment and a
second storage compartment formed in said housing; and a
refrigerant circuit including a compressor having a pressure
connection and a suction connection and the following connected in
series between said pressure connection and said suction
connection: a condenser, a first throttle point, a first evaporator
cooling said first storage compartment, a second throttle point
having an adjustable volume flow rate, and a second evaporator
cooling said second storage compartment.
11. The single-circuit refrigeration appliance according to claim
10, wherein said evaporators are cold wall evaporators.
12. The single-circuit refrigeration appliance according to claim
10, which further comprises: a first temperature sensor disposed in
said first storage compartment; and a control circuit connected to
said first temperature sensor and configured to increase said
volume flow rate of said second throttle point if cooling is
required in said first storage compartment.
13. The single-circuit refrigeration appliance according to claim
10, which further comprises: a second temperature sensor disposed
in said second storage compartment; and a control circuit connected
to said second temperature sensor and configured to reduce said
volume flow rate of said second throttle point if cooling is
required in said second storage compartment.
14. The single-circuit refrigeration appliance according to claim
10, wherein: said compressor is a speed-controlled compressor
having a rotational speed; and a control circuit is configured to
increase said rotational speed of said speed-controlled compressor
if cooling is required in said first and second storage
compartments.
15. The single-circuit refrigeration appliance according to claim
10, wherein said first throttle point has a volume flow rate, and
said volume flow rate of said second throttle point in a maximum
opening state is larger than said volume flow rate of said first
throttle point.
16. The single-circuit refrigeration appliance according to claim
10, wherein said second throttle point has a continuous valve.
17. The single-circuit refrigeration appliance according to claim
10, wherein at least said second storage compartment is operable as
a freezer compartment.
18. The single-circuit refrigeration appliance according to claim
10, wherein at least said first storage compartment is operable as
a normal refrigerator compartment.
Description
[0001] The present invention relates to a single-circuit
refrigeration appliance having two storage compartments which can
be temperature-controlled independently of one another.
[0002] In a single-circuit refrigeration appliance, a compressor, a
condenser and the evaporators of typically two storage compartments
are connected in series in a refrigerant circuit so that the entire
flow of refrigerant circulated by the compressor flows
consecutively through both evaporators.
[0003] The distribution of the available cooling power to the
evaporators of the storage compartments in such a single-circuit
refrigeration appliance is typically fixedly predefined by the
geometry and arrangement of the evaporators. The share of the
individual storage compartments in the overall cooling requirement
of the appliance varies however depending on the ambient
temperature. If such a refrigeration appliance is operated at a
lower ambient temperature than that for which it is optimized, the
cooling requirement of the warmer storage compartment reduces
proportionally to a greater extent than that of the colder storage
compartment, so that if the operation of the compressor is
controlled on the basis of the cooling requirement of the warmer
storage compartment, the colder storage compartment is no longer
cooled sufficiently. If by contrast the compressor operation were
controlled on the basis of the cooling requirement of the colder
storage compartment, the result would be excessive cooling of the
warmer storage compartment. A known solution to this problem is to
provide a heater in the warmer storage compartment, which can be
switched on during operation in a cold environment, in order to
artificially increase the cooling requirement of the warmer storage
compartment and thus to ensure a compressor life span which is
sufficient to also keep the colder storage compartment at a
setpoint temperature. It is obvious that such a heater severely
impairs the energy efficiency of the refrigeration appliance.
[0004] Dual-circuit refrigeration appliances allow the temperature
of two storage compartments of a refrigeration appliance to be
regulated independently of one another. With these appliances, the
refrigerant pipe comprises two branches, wherein refrigerant can be
applied to just one of the two evaporators by way of one of these
branches and either the other or both evaporators are supplied in
series with refrigerant by way of the other branch. The required
branching renders the refrigerant circuit considerably more
complicated and results in higher manufacturing costs than with a
single-circuit refrigeration appliance.
[0005] With no-frost refrigeration appliances, there is the option
of controlling the allocation of the cooling power to the storage
compartments, by the heat exchange between evaporator and storage
compartment being modulated with the aid of a ventilator. The use
of ventilators also increases the complexity and manufacturing
costs of the appliance; moreover, if the heat exchange between an
evaporator and an assigned storage compartment is blocked by
switching off the ventilator, said evaporator achieves very low
temperatures which likewise affect the energy efficiency of the
appliance.
[0006] The object of the invention is therefore to create a
single-circuit refrigeration appliance, which allows the
temperature of two storage compartments to be regulated
independently of one another, without having to heat one of the
storage compartments for this purpose.
[0007] The object is achieved by, in the case of a single-circuit
refrigeration appliance having a thermally insulated housing and a
refrigerant circuit, to which, between a pressure connection and a
suction connection of a compressor, a condenser, a first throttle
point, a first evaporator for cooling a first storage compartment
formed in the housing, a second throttle point and a second
evaporator cooling a second storage compartment formed in the
housing are connected in series, the second throttle point having
an adjustable volume flow rate. The adjustability of the volume
flow rate allows for different pressures to be set in the two
evaporators during operation of the compressor, and thus also for
different evaporation temperatures of the refrigerant in the two
evaporators, depending on the required temperature in the relevant
storage compartment.
[0008] This solution can be also be used in particular in cold wall
appliances and therefore allows for the manufacture of highly
energy-efficient and yet cost-effective refrigeration
appliances.
[0009] A control circuit can be connected to a first temperature
sensor arranged on the first storage compartment and to the second
throttle point and set up so as to increase the volume flow rate of
the second throttle point if cooling is required in the first
storage compartment. By increasing the volume flow rate, the
pressure of the refrigerant in the first evaporator is reduced and
the resulting lower evaporator temperature causes the first storage
compartment to be more intensively cooled.
[0010] By contrast, the control circuit can be connected to a
second temperature sensor arranged on the second storage
compartment and set up so as to reduce the volume flow rate of the
second throttle point if cooling is required in the second storage
compartment. This results in a pressure and thus also a temperature
rise on the first evaporator, so that this absorbs less heat from
the first storage compartment and a greater share of the available
cooling power is available to cool the second storage
compartment.
[0011] If there is a cooling requirement in both storage
compartments, the control circuit should be able to provide more
cooling power by increasing the rotational speed of the
speed-controlled compressor.
[0012] In a maximum opening state, the volume flow rate of the
second throttle point may be large in comparison with the volume
flow rate of the first throttle point. Therefore, if the second
throttle point is in the maximum opening state, the pressure
established by the compressor essentially reduces completely at the
first throttle point, and the pressure difference between the two
evaporators is low so that essentially the same temperatures can be
retained in both storage compartments.
[0013] Since the pressure in the downstream evaporator cannot be
higher than in the upstream first evaporator, the second storage
compartment is expediently configured for a lower operating
temperature than the first storage compartment. In particular, at
least the second storage compartment should be operable as a
freezer compartment. The setting of the second throttle point can
specify whether the first storage compartment can likewise be used
as a freezer compartment or at a higher temperature.
[0014] By contrast, at least the first storage compartment should
be operable as a normal refrigerator compartment, but this does not
rule out its use at lower temperatures, when the second throttle
point is set correspondingly.
[0015] In order to minimize the operating noise emission by the
refrigeration appliance, the second throttle point should comprise
a continuous valve. Since different flow cross-sections can
constantly be set on such a valve, pressure fluctuations of the
refrigerant are minimized during compressor operation, thereby
allowing the noise emission of the refrigeration appliance to be
kept low overall.
[0016] Further features and advantages of the invention will emerge
from the description of exemplary embodiments below, with reference
to the appended figures, in which:
[0017] FIG. 1 shows a schematic representation of the refrigerant
circuit of an inventive refrigeration appliance; and
[0018] FIG. 2 shows a schematic sectional view through the housing
of the refrigeration appliance.
[0019] The refrigerant circuit shown in FIG. 1 comprises a
speed-controlled compressor 1 with a pressure connection 2 and a
suction connection 3. A refrigerant pipe 4 coming from the pressure
connection 2 runs in the circulation direction of the refrigerant,
firstly via a condenser 5 and a first throttle point 6, here, as
standard, realized as a capillary line, to a first evaporator 7. A
second, adjustable throttle point 8 is disposed between an outlet
connection of the evaporator 7 and an inlet connection of a second
evaporator 9. An outlet connection of the evaporator 9 is connected
to the suction connection 3 of the compressor 1.
[0020] Two temperature sensors 10, 11 are arranged in storage
compartments 12, 13 cooled by the evaporators 7 or 9 and connected
to a control unit 14, which, on the basis of the temperatures
detected by the temperature sensors 10, 11, controls the rotational
speed of the compressor 1 and the volume flow rate of the throttle
point 8.
[0021] In a first operating mode, the control unit 14 continuously
compares the temperatures detected by the temperature sensors 10,
11 with setpoint temperatures for the storage compartments 12, 13
which can be set in the typical manner by a user. If the
temperature detected in one of the storage compartments 12, 13
significantly exceeds the set setpoint temperature by more than a
predetermined value .epsilon., the control unit 14 determines that
cooling of the relevant storage compartment is required. This
determination remains in existence until the temperature measured
in the relevant compartment drops by more than .epsilon. to below
the setpoint temperature of the relevant compartment.
[0022] If, for instance, a cooling requirement is determined in the
storage compartment 12, and not in the storage compartment 13, the
control unit 14 then increases the volume flow rate of the throttle
point 8 by a predetermined increment, thereby causing the pressure
drop to reduce at the throttle point 8 and to increase at the
throttle point 6. The pressure in the evaporator 7 reduces, thus
the boiling temperature of the refrigerant in the evaporator 7 also
reduces and the storage compartment 12 is cooled more intensively.
Since the power of the compressor 1 is not changed, the cooling
power available on the evaporator 9 reduces in exchange.
[0023] The increment can be fixedly predetermined or specified by
the control unit 14 in proportion to the deviation of the measured
temperature from the setpoint temperature of the relevant storage
compartment. If a temperature drop is determined a few minutes
after adjusting the throttle point 8, the adjustment of the
throttle point 8 is clearly sufficient; if no temperature drop is
determined, then the volume flow rate is incremented again.
[0024] If the storage compartment 13 heats up as a result and its
temperature exceeds the setpoint value for this compartment by more
than c, the control unit 14 determines that cooling is required in
the storage compartment 13. This determination also remains in
existence until the temperature in the storage compartment 13 falls
by at least c to below the setpoint value.
[0025] If cooling is required in the storage compartment 13, but
not in the storage compartment 12, the control unit 14 responds by
reducing the volume flow rate of the throttle point 8. As a result,
the pressure increases in the evaporator 7 and drops in the
evaporator 9. Consequently, the evaporation temperature in
evaporator 7 increases and less heat is absorbed from storage
compartment 12, so that a larger share of the refrigerant reaches
the evaporator 9 in the liquid state. Therefore, at the expense of
cooling the storage compartment 12, there is more cooling power
available to cool the storage compartment 13.
[0026] If the rotational speed of the compressor 1 is sufficient
overall to keep both compartments 12, 13 at their setpoint
temperatures, the phases of intensively cooling compartment 12 and
of intensively cooling compartment 13 thus alternate. If longer
time intervals exist in which neither compartment 12 nor
compartment 13 has a cooling requirement, the power of the
compressor 1 is greater than is needed to cool the compartments 12,
13 and in this case the rotational speed of the compressor 1 slows
down and is decremented in small steps in order to find a setting
value at which the power of the compressor 1 corresponds as
precisely as possible to the cooling requirement of the
compartments 12, 13.
[0027] A simultaneous cooling requirement in both compartments 12,
13 is an indication that the power of the compressor 1 is not
sufficient to keep the compartments 12, 13 at the setpoint
temperature, therefore, in such a case the control unit 14
increments the rotational speed of the compressor 1 slowly and in
steps until there is no longer a cooling requirement in one of the
storage compartments 12, 13.
[0028] Under stationary conditions, the afore-described hysteresis
when determining the existence or non-existence of a cooling
requirement leads to each of the storage compartments 12, 13
tending to have a phase-offset cooling requirement. The compressor
1 can therefore work very uniformly, with a rotational speed which
changes rarely and only by way of a few steps. Minor changes to the
volume flow rate on the throttle point 8 are sufficient to allocate
the cooling power to the storage compartments 12, 13. On account of
the continuous operation, the temperatures of both evaporators 7, 9
can be kept close to the setpoint temperature of the corresponding
storage compartment 12 or 13 in each case, which allows for a
highly energy-efficient operation. By the throttle point 8 being
formed by a continuous valve, the flow cross-section of which can
assume numerous positions while stationary that correspond to the
volume flow rates to be realized in each case, pressure
fluctuations in the refrigerant circuit which could result in the
emission of operating noises are avoided.
[0029] FIG. 2 shows a schematic sectional view through a
refrigeration appliance with the refrigerant circuit shown in FIG.
1. As standard, its housing 15 comprises a thermally insulated body
16, in which the two storage compartments 12, 13, each enclosed by
a door 17, are formed. The evaporators 7, 10 are each arranged
between an inner container 20 of the storage compartments 12, 13
and a surrounding insulation material layer 18. In the case of
storage compartment 12, they can only be arranged on a rear wall 19
or, in the case of storage compartment 13, they can also extend to
other walls of the inner container 20. The compressor 1 and, in the
case shown here, also the condenser 5 and the second throttle point
8 are accommodated in a machine compartment 21 on the rear side of
the body 15.
[0030] The evaporator 7 positioned upstream in the refrigerant
circuit is also the evaporator of the upper storage compartment 12
here, so that the circulation direction of the liquid refrigerant
through the evaporators 7, 9 essentially runs from the top down.
Since the pressure in the upstream evaporator 7 can never be lower
than in the downstream evaporator 9, storage compartment 12 can be
used as a normal refrigerator compartment and storage compartment
13 can be used a freezer compartment, but not vice versa.
[0031] A second operating mode can be set on the control unit 14,
in which the throttle point 8 is always held in a maximum flow
cross-section state, so that the pressure difference between the
two evaporators 7, 9 is negligible with respect to that at the
throttle point 6. In this operating state, depending on the setting
of the power of the compressor 1, both storage compartments 12, 13
can be operated with the same setpoint temperature, in particular
as a normal refrigerator compartment or as a freezer
compartment.
REFERENCE CHARACTERS
[0032] 1 compressor [0033] 2 pressure connection [0034] 3 suction
connection [0035] 4 refrigerant pipe [0036] 5 condenser [0037] 6
first throttle point [0038] 7 first evaporator [0039] 8 second
throttle point [0040] 9 second evaporator [0041] 10 temperature
sensor [0042] 11 temperature sensor [0043] 12 storage compartment
[0044] 13 storage compartment [0045] 14 control unit [0046] 15 body
[0047] 16 door [0048] 17 door [0049] 18 insulation material layer
[0050] 19 rear wall [0051] 20 inner container [0052] 21 machine
compartment
* * * * *