FIELD OF THE INVENTION
[0001] The present disclosure relates to the technical field of air conditioning, and in
particular to a method and system for determining a start frequency of an air conditioner.
BACKGROUND OF THE INVENTION
[0002] When an air conditioning system is operating in a cooling mode, a refrigerant coming
from a compressor reaches a condenser of an outdoor unit after passing through a four-way
valve; after being subjected to a throttling effect of an electronic expansion valve
of the outdoor unit, the refrigerant enters an indoor side, and after being subjected
to a throttling effect of an electronic expansion valve of an indoor unit, the refrigerant
enters an evaporator for heat exchange, and then enters the outdoor side; the refrigerant
passes through the four-way valve again being flowing into a gas-liquid separator,
and finally flows back to the compressor to form a complete cooling cycle.
[0003] In general situations, in order to enable the refrigerant in the air conditioning
system to quickly circulate to participate in the cooling or heating of the air conditioner,
in a soft-start stage, the compressor is typically started according to a maximum
start frequency. However, when the air conditioning system is operating in the cooling
mode, if a temperature of an outdoor environment is relatively high, especially in
a T3 working condition, under which the temperature of the outdoor environment may
reach up to 40-50°C, a discharge pressure of the compressor will be too high if the
start frequency is relatively high due to a limited condensing effect of the condenser,
which will easily cause a high pressure switch to be turned off so as to protect the
air conditioner by shutting down. This will result in a problem that the air conditioning
system cannot be turned on normally, thus affecting the normal use by the user.
[0004] Accordingly, there is a need in the art for a new method and system for determining
a start frequency of an air conditioner to solve the above problem.
SUMMARY OF THE INVENTION
[0005] In order to solve the above problem in the prior art, that is, to solve the problem
in the existing air conditioning systems that the air conditioning systems cannot
be turned on normally when the temperature of the outdoor environment is high, the
present disclosure provides a method and system for determining a start frequency
of an air conditioner, so that the air conditioner can be turned on normally without
failure even when the outdoor temperature is high.
[0006] The method for determining a start frequency of an air conditioner provided by the
present disclosure includes: acquiring an actual temperature value of an outdoor environment;
comparing the actual temperature value with a preset first temperature threshold and
a preset second temperature threshold, the first temperature threshold being lower
than the second temperature threshold; and determining the start frequency of the
air conditioner based on a comparison result.
[0007] As a preferred technical solution of the method for determining the start frequency
of the air conditioner provided by the present disclosure, the "determining the start
frequency of the air conditioner based on a comparison result" includes: determining
the start frequency of the air conditioner as a first start frequency, if the actual
temperature value is smaller than or equal to the first temperature threshold.
[0008] As a preferred technical solution of the method for determining the start frequency
of the air conditioner provided by the present disclosure, the "determining the start
frequency of the air conditioner based on a comparison result" includes: determining
the start frequency of the air conditioner according to a preset functional relationship
indicating a change of the start frequency with the actual temperature value, if the
actual temperature value is between the first temperature threshold and the second
temperature threshold.
[0009] As a preferred technical solution of the method for determining the start frequency
of the air conditioner provided by the present disclosure, the functional relationship
is configured to characterize a general trend of a decrease of the start frequency
with an increase of the actual temperature value.
[0010] As a preferred technical solution of the method for determining the start frequency
of the air conditioner provided by the present disclosure, the "determining the start
frequency of the air conditioner based on a comparison result" includes: determining
the start frequency of the air conditioner as 0, if the actual temperature value is
larger than or equal to the second temperature threshold.
[0011] In addition, the present disclosure correspondingly also provides a system for determining
a start frequency of an air conditioner, which includes: an acquisition module, which
is configured to acquire an actual temperature value of an outdoor environment; a
comparison module, which is configured to compare the actual temperature value with
a preset first temperature threshold and a preset second temperature threshold, the
first temperature threshold being lower than the second temperature threshold; and
a determination module, which is configured to determine the start frequency of the
air conditioner based on a comparison result.
[0012] As a preferred technical solution of the system for determining the start frequency
of the air conditioner provided by the present disclosure, the determination module
determines the start frequency of the air conditioner based on the comparison result
in the following way: if the actual temperature value is smaller than or equal to
the first temperature threshold, the start frequency of the air conditioner is determined
as a first start frequency.
[0013] As a preferred technical solution of the system for determining the start frequency
of the air conditioner provided by the present disclosure, the determination module
determines the start frequency of the air conditioner based on the comparison result
in the following way: if the actual temperature value is between the first temperature
threshold and the second temperature threshold, the start frequency of the air conditioner
is determined according to a preset functional relationship indicating a change of
the start frequency with the actual temperature value.
[0014] As a preferred technical solution of the system for determining the start frequency
of the air conditioner provided by the present disclosure, the functional relationship
is configured to characterize a general trend of a decrease of the start frequency
with an increase of the actual temperature value.
[0015] As a preferred technical solution of the system for determining the start frequency
of the air conditioner provided by the present disclosure, the determination module
determines the start frequency of the air conditioner based on the comparison result
in the following way: if the actual temperature value is larger than or equal to the
second temperature threshold, the start frequency of the air conditioner is determined
as 0.
[0016] In the method and system for determining the start frequency of the air conditioner
provided by the present disclosure, the acquired actual temperature value of the outdoor
environment is compared with a preset first temperature threshold and a preset second
temperature threshold, and the start frequency of the air conditioner is determined
based on a comparison result. In this way, for different actual temperature values
of the outdoor environment, the start frequency of the air conditioner is determined
respectively, so that the air conditioner can be turned on normally without failure
even when the outdoor temperature is high, which further optimizes the performance
of the air conditioner and improves the user's experience in use.
[0017] Further, in the method and system for determining the start frequency of the air
conditioner provided by the present disclosure, when the actual temperature value
of the outdoor environment is between the first temperature threshold and the second
temperature threshold, the start frequency of the air conditioner is determined according
to a preset functional relationship indicating a change of the start frequency with
the actual temperature value, and the functional relationship is configured to characterize
a general trend of a decrease of the start frequency with an increase of the actual
temperature value. In this way, when the actual temperature value of the outdoor environment
exceeds the first temperature threshold, with the increase of the actual temperature
value of the outdoor environment, it can still be ensured that the air conditioner
will be started quickly at a frequency as high as possible.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The method and system for determining a start frequency of an air conditioner of
the present disclosure will be described below with reference to the accompanying
drawings. In the drawings:
FIG. 1 is the schematic flow chart of the method for determining a start frequency
of an air conditioner of the present embodiment;
FIG. 2 is a first function image of the method for determining a start frequency of
an air conditioner of the present embodiment;
FIG. 3 is a second function image of the method for determining a start frequency
of an air conditioner of the present embodiment; and
FIG. 4 is a schematic structural diagram of an air conditioning system of the present
embodiment.
List of reference signs:
[0019] 1: compressor; 2: high pressure sensor; 3: high pressure switch; 4: four-way valve;
5: condenser; 6: outdoor electronic expansion valve; 7: indoor electronic expansion
valve; 8: evaporator; 9: low pressure sensor; 10: gas-liquid separator.
DETAILED DESCRIPTION OF THE EMBODIMENT(S) OF THE INVENTION
[0020] Preferred embodiments of the present disclosure will be described below with reference
to the accompanying drawings. It should be understood by those skilled in the art
that these embodiments are only used to explain the technical principle of the present
disclosure, and are not intended to limit the scope of protection of the present disclosure.
For example, although the present embodiment is described in connection with the air
conditioning system shown in FIG. 4, this is not intended to limit the scope of protection
of the present disclosure, and those skilled in the art can apply the present disclosure
to air conditioning systems with other structures without departing from the principle
of the present disclosure.
[0021] In the air conditioning system as shown in FIG. 4, when the air conditioning system
is operating in a cooling mode, an end
d of a four-way valve is conducted with an end c of the four-way valve, and an end
e of the four-way valve is conducted with an end s of the four-way valve. A refrigerant
coming out of a compressor 1 reaches an outdoor condenser 5 after passing through
the four-way valve 4; after being subj ected to a throttling effect of an outdoor
electronic expansion valve 6, the refrigerant enters an indoor side, and after being
subjected to a throttling effect of an indoor electronic expansion valve 7, the refrigerant
enters an evaporator 8 for heat exchange, and then enters the outdoor side; the refrigerant
passes through the four-way valve 4 again being flowing into a gas-liquid separator
10, and finally flows back to the compressor 1 to form a complete cooling cycle. A
high pressure sensor 2 and a high pressure switch 3 are also arranged between the
compressor 1 and the four-way valve, and a low pressure sensor 9 is also connected
to a refrigerant inlet side of the gas-liquid separator 10.
[0022] In general situations, in order to enable the refrigerant in the air conditioning
system to quickly circulate to participate in the cooling or heating of the air conditioner,
the frequency of the compressor 1 in a soft-start stage is typically set relatively
high, and is a fixed value (such as 40Hz). When the air conditioning system is implementing
cooling in a case where the temperature of the outdoor environment is relatively high,
due to the limited condensing effect of the condenser 5, if the start frequency is
still 40Hz at this time, a discharge pressure of the compressor 1 detected by the
high pressure sensor 2 will be too high, which will easily cause the high pressure
switch 3 to be turned off, thus making the air conditioning system enter a shutdown
protection state.
[0023] Taking the R410A refrigerant as an example, a turn-off value of the high pressure
switch is generally 4.15MPa, and a corresponding saturation temperature is 64.7°C.
When the temperature of the outdoor environment is high, the pressure of the refrigerant
in the air conditioning system will also increase accordingly.
[0024] Generally speaking, there are typically three types of air conditioners: cold air
type, heat pump type, and electric heating type, etc. Under different climate conditions,
the applicable environmental temperature ranges are not the same. According to the
provisions in the national standard GB/T7725-1996 "Room Air Conditioner", the climate
is divided into three types, namely, T1, T2, T3. Air conditioners for T3 climate type
have a highest working environment temperature of 52°C, and they can adapt to a tropical
climate; therefore, they are called tropical air conditioners. Air conditioners for
T2 climate type are called cold-zone air conditioners. Air conditioners for T1 climate
type are called temperate air conditioners.
[0025] Taking an air conditioner for T3 climate type as an example, when the specified highest
outdoor environment temperature at which the air conditioner can operate is 52°C,
the corresponding system pressure is 3.2MPa. If the start frequency of the compressor
is unreasonably set at this time (for example, it is still 40Hz), then the discharge
pressure 2 can easily reach 4.15MPa, which will further trigger the turn-off failure
of the high pressure switch 3, so that the air conditioning system cannot be turned
on normally, thus affecting the normal use by the user.
[0026] In order to solve the above problem in the prior art, that is, to solve the problem
in the existing air conditioning systems that the air conditioning systems cannot
be turned on normally when the temperature of the outdoor environment is high, the
present embodiment provides a method and system for determining a start frequency
of an air conditioner, so that the air conditioner can be turned on normally without
failure even when the outdoor temperature is high.
[0027] As shown in FIG. 1, the method for determining a start frequency of an air conditioner
provided by the present embodiment includes:
S100: acquiring an actual temperature value of an outdoor environment;
S200: comparing the actual temperature value with a preset first temperature threshold
and a preset second temperature threshold, the first temperature threshold being lower
than the second temperature threshold; and
S300: determining the start frequency of the air conditioner based on a comparison
result.
[0028] Exemplarily, a temperature sensor may be provided in the outdoor environment to detect
the actual temperature value of the outdoor environment. The temperature sensor may
be communicatively connected to a controller of the air conditioning system, and the
temperature sensor can feed the acquired actual temperature value of the outdoor environment
back to the controller of the air conditioning system. The controller of the air conditioning
system compares the actual temperature value with the preset first temperature threshold
and the preset second temperature threshold, and determines the start frequency of
the air conditioner based on the comparison result.
[0029] In the method for determining the start frequency of the air conditioner provided
by the present embodiment, the acquired actual temperature value of the outdoor environment
is compared with a preset first temperature threshold and a preset second temperature
threshold respectively, and the start frequency of the air conditioner is determined
based on a comparison result. In this way, for different actual temperature values
of the outdoor environment, the start frequency of the air conditioner is determined
respectively, so that the air conditioner can be turned on normally without failure
even when the outdoor temperature is high, which further optimizes the performance
of the air conditioner and improves the user's experience in use.
[0030] As a preferred implementation of the above method for determining the start frequency
of the air conditioner provided by the present embodiment, in the above step S300,
the "determining the start frequency of the air conditioner based on a comparison
result" includes: determining the start frequency of the air conditioner as a first
start frequency, if the actual temperature value is smaller than or equal to the first
temperature threshold.
[0031] Exemplarily, the first temperature threshold is a critical value of the temperature
of the outdoor environment, which has a negligible influence on the start frequency
of the air conditioner; for example, it may be 35°C. Moreover, a rated value for performing
cooling by the air conditioners for T1 climate type is also 35°C, and most air conditioning
systems are developed from this rated value. In a specific application, the first
temperature threshold may be any value between 32°C and 38°C; the first start frequency
may be the maximum start frequency of the air conditioner, such as 40Hz; when the
actual temperature value of the outdoor environment is lower than or equal to the
first temperature threshold, the air conditioner can be started according to the maximum
start frequency value, so as to ensure that the air conditioner is started quickly
at a frequency as high as possible.
[0032] As a preferred implementation of the above method for determining the start frequency
of the air conditioner provided by the present embodiment, in the above step S300,
the "determining the start frequency of the air conditioner based on a comparison
result" includes: determining the start frequency of the air conditioner according
to a preset functional relationship indicating a change of the start frequency with
the actual temperature value, if the actual temperature value is between the first
temperature threshold and the second temperature threshold.
[0033] Exemplarily, the second temperature threshold may be the highest temperature value
of the outdoor environment when the air conditioner operates normally. In a case where
the actual temperature value of the outdoor environment is between the first temperature
threshold and the second temperature threshold, if the start frequency of the air
conditioner is high, it is easy to cause the air conditioner to fail to adapt to the
actual temperature of the outdoor environment, resulting in an overly high discharge
pressure of the compressor to trigger the shutdown protection of the air conditioning
system. Therefore, when the environmental temperature is high, the start frequency
of the air conditioner can be appropriately reduced to ensure that the air conditioner
is turned up normally. It is a convenient and practical method to determine the start
frequency of the air conditioner through the preset functional relationship indicating
a change of the start frequency with the actual temperature value.
[0034] As a preferred implementation of the above method for determining the start frequency
of the air conditioner provided by the present embodiment, the functional relationship
is configured to characterize a general trend of a decrease of the start frequency
with an increase of the actual temperature value.
[0035] Exemplarily, the functional relationship can generally characterize the relationship
that the start frequency decreases with the increase of the actual temperature value,
and the functional relationship may be a linear relationship corresponding to a straight
line A as shown in FIG. 2, or a nonlinear relationship corresponding to a concave
curve B as shown in 2, or a nonlinear relationship corresponding to a convex curve
C as shown in FIG. 2, and a nonlinear relationship corresponding to a stepped fold
line D as shown in FIG. 3. Those skilled in the art can make specific settings according
to differences in the performance of the compressor, the type of the refrigerant,
etc. Further, when the functional relationship is the linear relationship corresponding
to the straight line A as shown in FIG. 2, in an example in which the first temperature
threshold is 35°C, the second temperature threshold is 54°C, the maximum start frequency
of the air conditioner is 40Hz and the lowest effective start frequency of the air
conditioner is 10Hz, the corresponding functional relationship is
f=(-1.58
∗Tao+95.26)Hz, where Tao represents the actual temperature value of the outdoor environment.
[0036] In addition, the minimum start frequency (or the lowest effective start frequency)
is generally recorded in the compressor specification book, so when the start frequency
of the air conditioner is determined according to the actual temperature value of
the outdoor environment, it should be ensured that the start frequency of the air
conditioner is not lower than the minimum start frequency so that the air conditioner
can be started normally. In both the function images shown in FIGS. 2 and 3, 10Hz
is used as the lowest effective start frequency of the air conditioner.
[0037] As a preferred implementation of the above method for determining the start frequency
of the air conditioner provided by the present embodiment, in the above step S300,
the "determining the start frequency of the air conditioner based on a comparison
result" includes: determining the start frequency of the air conditioner as 0, if
the actual temperature value is larger than or equal to the second temperature threshold.
[0038] Exemplarily, the second temperature threshold may be the highest temperature value
of the outdoor environment when the air conditioner operates normally. For example,
as to the air conditioners for T3 climate type, the highest working environment temperature
is 52°C. In both FIG. 2 and FIG. 3, the second temperature threshold of 54°C is taken
as an example. When the actual temperature of the outdoor environment is higher than
or equal to the second temperature threshold, in order to protect the air conditioning
system from accidents, the air conditioner may be prohibited from starting.
[0039] It should be noted that although the specific steps of the method of the present
disclosure have been described in detail above, those skilled in the art can combine
and split these steps and modify the order of these steps without departing from the
basic principle of the present disclosure. The thus-amended technical solutions do
not change the basic concept of the present disclosure, and therefore also fall within
the scope of protection of the present disclosure.
[0040] It should be understood by those skilled in the art that the method for determining
the start frequency of the air conditioner provided by the present embodiment may
be stored as a program in a computer-readable storage medium. The storage medium includes
several instructions for causing a computer device (which may be a personal computer,
a server, or a network device, etc.) or a processor to execute some steps of the methods
of various embodiments of the present disclosure. The above storage medium includes:
a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM),
a magnetic disk or an optical disk, and other media that can store program codes.
[0041] In addition, the present disclosure correspondingly also provides a system for determining
a start frequency of an air conditioner, which includes: an acquisition module, which
is configured to acquire an actual temperature value of an outdoor environment; a
comparison module, which is configured to compare the actual temperature value with
a preset first temperature threshold and a preset second temperature threshold, the
first temperature threshold being lower than the second temperature threshold; and
a determination module, which is configured to determine the start frequency of the
air conditioner based on a comparison result.
[0042] As a preferred implementation of the system for determining the start frequency of
the air conditioner provided by the present embodiment, the determination module determines
the start frequency of the air conditioner based on the comparison result in the following
way: if the actual temperature value is smaller than or equal to the first temperature
threshold, the start frequency of the air conditioner is determined as a first start
frequency.
[0043] As a preferred implementation of the system for determining the start frequency of
the air conditioner provided by the present embodiment, the determination module determines
the start frequency of the air conditioner based on the comparison result in the following
way: if the actual temperature value is between the first temperature threshold and
the second temperature threshold, the start frequency of the air conditioner is determined
according to a preset functional relationship indicating a change of the start frequency
with the actual temperature value.
[0044] As a preferred implementation of the system for determining the start frequency of
the air conditioner provided by the present embodiment, the functional relationship
is configured to characterize a general trend of a decrease of the start frequency
with an increase of the actual temperature value.
[0045] As a preferred implementation of the system for determining the start frequency of
the air conditioner provided by the present embodiment, the determination module determines
the start frequency of the air conditioner based on the comparison result in the following
way: if the actual temperature value is larger than or equal to the second temperature
threshold, the start frequency of the air conditioner is determined as 0.
[0046] The system for determining the start frequency of the air conditioner provided by
the present embodiment corresponds to the method for determining the start frequency
of the air conditioner that has been described above, so the system for determining
the start frequency of the air conditioner in the present embodiment will not be described
repeatedly. Those skilled in the art can still clearly understand the present embodiment,
and can implement it smoothly on the basis of the understanding.
[0047] In the system for determining the start frequency of the air conditioner provided
by the present embodiment, the comparison module compares the acquired actual temperature
value of the outdoor environment with a preset first temperature threshold and a preset
second temperature threshold, and the determination module determines the start frequency
of the air conditioner based on a comparison result of the comparison module. In this
way, for different actual temperature values of the outdoor environment, the start
frequency of the air conditioner can be determined respectively by the system for
determining the start frequency of the air conditioner provided by the present embodiment,
so that the air conditioner can be turned on normally without failure even when the
outdoor temperature is high, which further optimizes the performance of the air conditioner
and improves the user's experience in use.
[0048] It should be noted that, the system for determining the start frequency of the air
conditioner provided by the present embodiment is only illustrated through the division
of the above functional modules (such as the acquisition module, the comparison module,
the determination module, etc.). In practical applications, the above functional modules
can be completed by different functional modules as required, that is, the functional
modules in the embodiments of the present disclosure can be further decomposed or
combined. For example, the functional modules in the above embodiment can be combined
into one functional module, or can be further split into several sub-modules, so as
to complete all or part of the functions described above. The names of the functional
modules involved in the embodiments of the present disclosure are only provided for
distinguishing, and should not regarded as improper limitations to the present disclosure.
[0049] Various embodiments of the present disclosure may be implemented in hardware, or
in software modules running on one or more processors, or in a combination thereof.
It should be understood by those skilled in the art that a microprocessor or a digital
signal processor (DSP) may be used in practice to implement some or all the functions
of some or all of the components in the server and client according to the embodiments
of the present disclosure. The present disclosure may also be implemented as a device
or apparatus program (e.g., a PC program and a PC program product) for executing a
part or entirety of the method described herein. Such a program for implementing the
present disclosure may be stored on a PC-readable medium, or may be in the form of
one or more signals. Such signals may be downloaded from Internet websites, or provided
on carrier signals, or provided in any other form.
[0050] Furthermore, it can be understood by those skilled in the art that although some
of the embodiments described herein include some features included in other embodiments
rather than other features, the combination of features of different embodiments is
meant to be within the scope of the present disclosure, and different embodiments
can be formed. For example, in the claims of present disclosure, any of the claimed
embodiments may be used in any combination.
[0051] Hitherto, the technical solutions of the present disclosure have been described in
connection with the preferred embodiments shown in the accompanying drawings, but
it is easily understood by those skilled in the art that the scope of protection of
the present disclosure is obviously not limited to these specific embodiments. Without
departing from the principles of the present disclosure, those skilled in the art
can make equivalent changes or replacements to relevant technical features, and all
the technical solutions after these changes or replacements will fall within the scope
of protection of the present disclosure.
1. A method for determining a start frequency of an air conditioner, comprising:
acquiring an actual temperature value of an outdoor environment;
comparing the actual temperature value with a preset first temperature threshold and
a preset second temperature threshold, the first temperature threshold being lower
than the second temperature threshold; and
determining the start frequency of the air conditioner based on a comparison result.
2. The method for determining a start frequency of an air conditioner according to claim
1, wherein the "determining the start frequency of the air conditioner based on a
comparison result" comprises:
determining the start frequency of the air conditioner as a first start frequency,
if the actual temperature value is smaller than or equal to the first temperature
threshold.
3. The method for determining a start frequency of an air conditioner according to claim
1, wherein the "determining the start frequency of the air conditioner based on a
comparison result" comprises:
determining the start frequency of the air conditioner according to a preset functional
relationship indicating a change of the start frequency with the actual temperature
value, if the actual temperature value is between the first temperature threshold
and the second temperature threshold.
4. The method for determining a start frequency of an air conditioner according to claim
3, wherein the functional relationship is configured to characterize a general trend
of a decrease of the start frequency with an increase of the actual temperature value.
5. The method for determining a start frequency of an air conditioner according to claim
1, wherein the "determining the start frequency of the air conditioner based on a
comparison result" comprises:
determining the start frequency of the air conditioner as 0, if the actual temperature
value is larger than or equal to the second temperature threshold.
6. A system for determining a start frequency of an air conditioner, comprising:
an acquisition module, which is configured to acquire an actual temperature value
of an outdoor environment;
a comparison module, which is configured to compare the actual temperature value with
a preset first temperature threshold and a preset second temperature threshold, the
first temperature threshold being lower than the second temperature threshold; and
a determination module, which is configured to determine the start frequency of the
air conditioner based on a comparison result.
7. The system for determining a start frequency of an air conditioner according to claim
6, wherein the determination module determines the start frequency of the air conditioner
based on the comparison result in the following way:
if the actual temperature value is smaller than or equal to the first temperature
threshold, the start frequency of the air conditioner is determined as a first start
frequency.
8. The system for determining a start frequency of an air conditioner according to claim
6, wherein the determination module determines the start frequency of the air conditioner
based on the comparison result in the following way:
if the actual temperature value is between the first temperature threshold and the
second temperature threshold, the start frequency of the air conditioner is determined
according to a preset functional relationship indicating a change of the start frequency
with the actual temperature value.
9. The system for determining a start frequency of an air conditioner according to claim
8, wherein the functional relationship is configured to characterize a general trend
of a decrease of the start frequency with an increase of the actual temperature value.
10. The system for determining a start frequency of an air conditioner according to claim
6, wherein the determination module determines the start frequency of the air conditioner
based on the comparison result in the following way:
if the actual temperature value is larger than or equal to the second temperature
threshold, the start frequency of the air conditioner is determined as 0.