JPH0534049A - Defrosting operation control device for freezing device for container - Google Patents

Abstract

PURPOSE:To save a consumption power of a defrosting operation of a freezer device for a container. CONSTITUTION:A refrigerant circuit 7 in which a compressor 1, a condensor 2, an expansion valve 4 and an evaporator 5 are connected in sequence is provided and an evaporator 5 is set within a refrigerator. When a defrosting instruction for the frosted evaporator 5 is provided and when the temperature of sucked air or blown air is lower than a predetermined temperature value under an operation of a defrosting operation control means 51, a heating and defrosting operation for heating the evaporator 5 is carried out by a heating means and at the same time when a temperature of the sucked air is higher than a predetermined temperature value, the compressor 1 is topped for its operation and an evaporator fan 5a is operated to perform an off-cycle defrosting operation. With such an arrangement, power consumption required for performing a defrosting operation is reduced. In the case that an off-cycle defrosting operation is carried out continuously longer than a predetermined time, a subsequence defrosting operation is changed over to a defrosting operation through a heating and defrosting operation. With such an arrangement, accumulation of a residual frost is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a defrosting operation control device for a container refrigeration system, and more particularly to measures for reducing power consumption.

[0002]

2. Description of the Related Art Conventionally, as a defrosting operation control device for a refrigeration system, for example, as disclosed in Japanese Patent Publication No. 59-5813, a refrigeration system provided with a heat pump circuit capable of switching between heating and cooling cycles is used. As the frost operation control device, when the ambient temperature of the heat exchanger is lower than a predetermined value, the heating cycle is performed in a reverse cycle to introduce the discharged refrigerant into the heat exchanger, while the ambient temperature of the heat exchanger is equal to or higher than the predetermined value. It is a well-known technique to stop the compressor of the refrigerant circuit and operate only the fan of the heat exchanger to perform the defrost operation with a small amount of power consumption.

[0003]

By the way, in a container refrigerating apparatus for refrigerating and freezing fresh food such as fish meat, vegetables and fruits, in particular, in order to avoid freezing of fruits and vegetables, the temperature is about 5 to 10 ° C. The inside of the refrigerator is kept at a relatively high temperature. Further, even in the operation in the frozen mode, the pull-down operation is performed at a relatively high temperature. However, conventionally, in a container refrigerating apparatus, there is no operation control apparatus having an off-cycle defrost function as shown in the above publication, and it relies exclusively on a reverse cycle defrost or a defrost means for electrically heating the evaporator. It was not possible to sufficiently reduce the power consumption in the defrosting operation.

[0004]

Means for Solving the Problems To achieve the above object, the means of the invention of claim 1 is, as shown in FIG. 1, a compressor (1), a condenser (2), an expansion valve (4). ) And an evaporator (5a) attached with an evaporator fan (5a) are sequentially connected to the refrigerant circuit (7), and the evaporator (5) is installed in a refrigerator. And

As a defrosting operation control device for the container refrigeration system, heating means (50) for heating the evaporator (5) and the intake air temperature or blown air of the evaporator fan (5a). A blower temperature detecting means (Ths or Thr) for detecting the temperature of the temperature, and an intake air temperature or an outlet air temperature detected by the blower temperature detecting means (Ths or Thr) in accordance with a defrosting command is higher than a predetermined temperature value. When the temperature is low, the heating means (50) performs heating defrosting to heat the evaporator (5), while when the intake air temperature or the blown air temperature is equal to or higher than a predetermined temperature value, the refrigerant circuit (7).
Of the evaporator fan (5)
and a defrosting operation control means (51) for controlling off-cycle defrost for operating a).

In addition to the invention of claim 1, the means taken by the invention of claim 2 is such that the higher the intake air temperature, the higher the intake air temperature in accordance with the intake air temperature detected by the blast temperature detecting means (Ths or Thr). The defrosting time switching means (52) is set to shorten the off-cycle defrosting time by the defrosting operation control means (51).

According to a third aspect of the present invention, in the invention according to the first or second aspect, the defrosting operation interval by the defrosting operation control means (51) is shortened during pulldown.
The in-range is provided with operation interval switching means (53) for setting the defrosting operation interval to be long.

According to a fourth aspect of the present invention, in the first, second or third aspect of the present invention, the evaporator fan (5a) has an air volume switching function. Then, during the off-cycle defrost operation by the defrosting operation control means (51),
An air volume control means (54) for controlling the air volume of the evaporator fan (5a) to a high air volume is provided.

According to the invention as defined in claim 5, when the invention according to claim 1, 2, 3 or 4 is performed a predetermined number of times or more, the next defrosting operation is forcibly performed by heating defrosting. It is configured to switch to the defrosting operation by.

[0010]

With the above construction, in the invention of claim 1, when a defrosting command is issued during the operation of the container refrigerating apparatus, the defrosting operation control means (51) melts the frost formed on the evaporator (5). The defrosting operation for performing is performed. At that time, when the blast temperature is lower than the predetermined value, the defrosting operation control means (51) performs heating defrosting using the heating means (50), while the blast temperature detection means (Ths or Thr) detects it. If the blowing temperature is equal to or higher than the predetermined temperature, so-called off-cycle defrosting is performed in which the operation of the compressor (1) is stopped and the evaporator fan (5a) is operated. Therefore, in particular, in a container refrigeration system in which the operation mode is variously changed depending on the type of cargo stored in the refrigerator, the evaporator fan (5a) using the air inside the refrigerator is used according to the changed set temperature and operation mode. Since it is possible to perform the off-cycle defrosting only by the operation (4), the power consumption is reduced as compared with the defrosting by the heating means (50).

According to a second aspect of the present invention, in the first aspect of the invention, the defrosting time switching means (52) shortens the off-cycle defrosting time by the defrosting operation control means (51) as the intake air temperature becomes higher. Therefore, the off-cycle defrost time can be selected according to the temperature in the refrigerator, that is, the amount of the air heat source, and wasteful defrost after the frost is melted can be suppressed.

According to the third aspect of the present invention, the operation interval switching means (53) shortens the operation interval between the defrost operation and the next defrost operation when the amount of frost is large and when pulling down, and operates in the in-range where the amount of frost is small. Since the intervals are switched to be longer, the cooling capacity is prevented from being deteriorated due to an excessive amount of frost.

In the invention of claim 4, the air volume control means (5
The air volume of the evaporator fan (5a) is controlled by 4) so as to operate at a high air volume during the off-cycle defrost operation, so that the amount of heat exchange between the intake air and the frost formation of the evaporator (5) increases and the defrost Driving time is reduced.

According to the invention of claim 5, in the invention of each of the above claims, when the defrosting operation control means (51 performs the off cycle defrost continuously for a predetermined number of times or more,
Since the heating defrosting is performed, even when the residual defrosting occurs in the off-cycle defrosting, the cooling ability does not decrease due to the accumulation thereof, and the stable cooling ability can be obtained.

[0015]

Embodiments of the present invention will be described below with reference to the drawings starting from FIG.

FIGS. 2 and 3 respectively show vertical side structures of the inside and outside of the refrigerator of the container according to the embodiment of the present invention. (1) is a compressor, (2) is a condenser fan (2).
a), an air-cooled condenser equipped with (2a), (3) a water-cooled condenser, (4) a temperature-sensitive expansion valve equipped with a temperature-sensitive tube (4a), and (5) two units Evaporator fan (5a), (5
An evaporator provided with a), wherein each of the above devices (1) to
(5) is sequentially connected to the closed circuit by the refrigerant pipe (6),
A refrigerant circuit (7) is configured such that cold heat obtained by heat exchange with outside air in the condenser (2) is applied to the inside air in the evaporator (5).

Further, a hot gas bypass passage (10) for bypassing the discharged refrigerant (hot gas) from the discharge line of the refrigerant circuit (7) to the inlet side of the evaporator (5) is provided, and its branch. At the point, there is a hot gas control valve (20M) that is a proportional three-way valve that regulates the amount of refrigerant bypass from the condenser (2), (3) side to the hot gas bypass passage (10) side. It is arranged. A drain pan heater (11) for heating the evaporator (5) is provided immediately above the drain pan (12) that receives the condensed water of the evaporator (5), and the hot gas bypass passage (10) is provided. Is connected to the inlet pipe of the evaporator (5) through the drain pan heater (11) and bypasses the drain pan heater (11) immediately before the drain pan heater (11) to communicate with the inlet pipe of the evaporator (5). A bypass pipe is provided and a drain pan three-way solenoid valve (2) for switching the flow of the refrigerant between the drain pan heater (11) side and the bypass pipe side at a branch point of the hot gas bypass passage (10).
0R4) is provided. The hot gas bypass passage (10) and the drain heater (11) constitute a heating means (50) for heating the evaporator (5).

Further, (20R1) and (20R2) are
An electromagnetic valve for the downstream side refrigerant and an electromagnetic valve for the upstream side refrigerant that are used for performing the lightweight pump down, (20R3) is a three-way pressure equalizing electromagnetic time valve, and (63L) is for detecting the end of the pump down operation. The low pressure switch (21) is an accumulator for removing the liquid refrigerant in the suction refrigerant.

Further, (30) is a controller for controlling the operation of the refrigerating apparatus, (31) is a switch box for housing electric parts such as an inverter, and (Ths) is the evaporator fans (5a), (5a). A suction sensor as a blower temperature detecting means for detecting the temperature of the intake air to the (Th
r) is a blowout sensor as a blowing temperature detecting means for detecting the temperature of blown air into the chamber, (The) is attached to the suction line, and the suction refrigerant temperature becomes a constant value (for example, a value of about 35 ° C.). A completion thermistor for sometimes detecting the completion of defrosting, the controller (30):
The operation of each device is controlled according to the output of each sensor (Thr), (Ths), (The).

During the operation of the container refrigeration system, the refrigerant discharged from the discharge pipe (6a) of the compressor (1) flows into the air-cooled condenser (2) and the water-cooled condenser (3), and each condenser (2). ，
After being condensed in (3), decompressed by the expansion valve (4) and evaporated in the evaporator (5), the suction pipe (6b) is opened to circulate back to the compressor (1).

Here, the control contents of the controller (30) will be described with reference to the flow charts of FIGS.

FIG. 4 shows the main flow. When the freezing operation is started, the interval short timer (IOS) for off-cycle defrost is activated in step ST1, and the interval short timer (I) is started in step ST2.
When (OS) counts up, the process proceeds to step ST3, and it is determined whether or not the in-range is entered. On the other hand, at the same time as step ST1 and step ST4, an interval long timer (IO) for off-cycle defrost having a longer set time than the short timer (IOS) is set.
L) is activated and the interval long timer (IOL) counts up in step ST5, step S
Proceed to T6. Then, if the temperature inside the refrigerator is in the in-range in the determination in step ST3, it is determined that the frost formation amount is small, the process moves to step 5, and the interval long timer (IOL) counts up, and then the temperature inside the refrigerator If is not in the in-range, that is, in the pull-down mode, it is determined that the amount of frost is large, and the process proceeds to step ST6 without any change.

Next, in step ST6, the suction air temperature Ts detected by the suction sensor (Ths) is compared with a predetermined temperature (5 ° C.), and if Ts ≧ 5 ° C., step ST
7, the number of defrosting by off-cycle defrost N
It is determined whether or not od is 5 times or less in succession. If Nod ≧ 5, Nod is counted in step ST8, and then off cycle defrost is controlled in step ST9.

At the same time as steps ST1 and ST4, at steps ST10 and ST13, an interval short timer (IHS) for hot gas defrosting is performed.
Then, when the interval long timer (IHL) having a set time longer than the short timer (IHS) is activated and the interval short timer (IHS) counts up, it is determined in step ST12 whether the internal cold storage temperature is in the in-range or not. If it is not in the in-range, it remains as it is, and if it is in the in-range, step ST14
After waiting for the interval long timer (IHL) to count up, the defrosting command is output respectively, and the process proceeds to step ST15 to clear the defrosting number Nod, and at step ST16, control of the hot gas defrost is performed. To do. Here, the short timer (IOS) for off-cycle defrost is shorter than the short timer (IHS) for hot gas defrost, and the long timer (IOL) for off-cycle defrost is a long timer (for hot gas defrost). It is set to a shorter time than IHL).

On the other hand, if the result of the determination in step ST6 is Ts
When it is not ≧ 5 ° C., it is determined that the intake air temperature Ts is too low to perform the off-cycle defrost, and when it is not Nod ≦ 5 in the determination in step ST7, that is, the defrost operation by the off-cycle defrost is continuously performed six times. When it reaches, it is judged that there is a possibility that residual frost is accumulated in the evaporator (5), and the process proceeds to steps ST15 and ST16, respectively, where hot gas defrosting is performed.

Next, FIG. 5 is a sub-flow showing the contents of the off-cycle defrost control, which is step SS1.
Then, an off-cycle defrost start command is output, and the defrost lamp is turned on in step SS2. Then, in step SS3, it is determined whether or not Ts ≦ 10 ° C. in order to set the defrost operation time by off-cycle defrost.
Then, if Ts ≦ 10 ° C., it is determined that the defrosting ability is low, and a long timer (DOL) for measuring the frost operation time (having a set time of about 15 minutes, for example) is activated in step SS4, and Ts ≦ If it is not 10 ° C, it is determined that the defrosting ability is sufficiently high, and in step SS5, a short timer (DOS)
After operating (for example, having a set time of about 10 minutes), the process proceeds to step SS6 to drive the evaporator fans (5a) and (5a) from low air volume "Lo" to high air volume "during normal refrigeration operation. Hi ”, and in step SS7, the compressor (1), the condenser fan (2
a) and (2a) are stopped, and the downstream solenoid valve (20R1)
And, the hot gas control valve (20M) is closed, and step SS
At 8, the defrosting operation is performed until the timer (DOS or DOL) counts up, and then at step SS9, the freezing operation is resumed.

FIG. 6 shows the control contents of the hot gas defrost, in which a defrosting operation start signal is output in step SS10, the defrost lamp is turned on in step SS11, and then the evaporator fan (5a), (5
a) is stopped, the downstream refrigerant solenoid valve (20R1) is closed in step SS13 to start the lightweight pump down operation, and the low pressure switch (63L) is turned off in step SS14. Open the solenoid valve for refrigerant (20R1) and set the solenoid valve for refrigerant on the upstream side (20R2)
Is closed to start the injection of the refrigerant, and in step SS16, the hot gas control valve (20M) is opened 100%, the drain pan heater three-way valve (20R4) is turned on and opened, and in step SS17, the compressor (1) is opened. And condenser fan (2
a) and (2a) are stopped for 20 seconds, and step SS18
Then, the compressor (1) and the condenser fans (2a) and (2a) are operated to perform the defrosting operation by the hot gas defrost.

When the defrost completion thermostat (The) is turned off in step SS19, the hot gas control valve (20M) is closed and the downstream side solenoid valve (20R1) and the upstream side refrigerant are also turned on in step SS20. Solenoid valve (20R2) for use, the defrost lamp is turned off, and in step SS21, the evaporator fan (5a),
(5a) is operated with a delay of 60 seconds, and step SS2
At 2, the operation returns to the freezing operation.

In the above flow, steps ST6 to S6
The defrosting operation control means (51) according to the invention of claim 1 is configured by the control of T9 and steps ST15, ST16, and the defrosting operation control means (51) according to the invention of claim 1 is constituted by the control of steps SS4 and SS5.
The defrosting time switching means (52) referred to in the invention is constituted. In addition, steps ST1 to ST5, ST10 to ST1
By the control of 4, the operation interval switching means (53) according to the invention of claim 3 is configured, and by the control of step SS6,
The air volume control means (54) according to the invention of claim 4 is constituted.

Therefore, in the above embodiment, when a defrosting command is issued during the operation of the container refrigeration system, the defrosting operation control means (51) defrosts the evaporator (5) to melt the frost. Driving is performed. At that time, the suction sensor (Th
If the intake air temperature Ts detected in s) is equal to or higher than the predetermined temperature (5 ° C. in the above embodiment), the defrosting operation control means (5
By 1), so-called off-cycle defrost is performed in which the operation of the compressor (1) is stopped and the evaporator fans (5a) and (5a) are operated. Particularly, in the container refrigeration system, it is necessary to change the set temperature and the operation mode in various ways depending on the type of cargo stored in the refrigerator. In the case of cargo that does not like freezing, such as vegetables and fruits, it is necessary to maintain the inside of the refrigerator at a relatively high temperature, and usually the chilled mode is maintained instead of the frozen mode. In such a case, since the defrosting function can be exhibited only by operating the evaporator fans (5a), (5a) using the air in the refrigerator, the hot gas defrost performed by operating the normal compressor (1) is performed. Power consumption is reduced as compared with defrosting by a heating means (50) such as defrosting that heats the evaporator and the evaporator (5) with an electric heater. On the other hand, when the intake air temperature Ts is lower than the predetermined temperature (5 ° C. in the above embodiment), the defrosting operation control means (5
According to 1), since defrosting is performed using the heating means (50), the defrosting ability is not insufficient and excessive residual frosting does not occur.

That is, as in the above embodiment, the off-cycle defrost for stopping the compressor (1) in the defrosting operation according to the level of the intake air temperature Ts (or the blown air temperature Tu) and the heating means (50). The defrosting operation can be performed according to the operating state of the container refrigerating machine with various operating modes and the type of load by switching to the heating defrosting method using the The reduction can be achieved.

In the above-described embodiment, the off-cycle defrost and the hot gas defrost are switched depending on whether the intake air temperature Ts is equal to or higher than a predetermined value.
You may make it switch according to the height of r.

Further, in that case, as in the above embodiment, the defrosting time switching means (52) is set so that the higher the intake air temperature, the shorter the off-cycle defrost time by the defrosting operation control means (51). By doing so, the off-cycle time corresponding to the internal temperature, that is, the amount of the air heat source can be taken, and useless defrost after the frost is melted can be suppressed, and the defrost efficiency can be improved.

Further, the operation interval switching means (53) shortens the operation interval between the defrost operation and the next defrost operation when the amount of frost is large and pulls down, and lengthens the operation interval when the in-range has a small amount of frost. By switching, it is possible to prevent the cooling capacity from decreasing due to an excessive amount of frost formation. In particular, as in the above example,
Interval timer for off-cycle defrost (IO
S and IOL) set time and heating defrost interval timer (IHS and IHL) set time 2
By providing different types and shortening the off-cycle defrosting interval, defrosting can be performed with an amount of frost that corresponds to the defrosting function that differs depending on the type of defrosting, and a significant effect can be obtained.

In normal operation, the evaporator fan (5
Even when the air volumes of a) and (5a) are operated at a low air volume “Lo”, the intake air and the evaporator (by the operation at a high air volume “Hi” by the air volume control means (54) during the off-cycle defrost operation. It is possible to increase the amount of heat exchange with frost formation in 5) and shorten the defrost operation time.

When the off-cycle defrost is continuously performed a predetermined number of times or more, the heating defrost is controlled so that even if the residual defrost occurs in the off-cycle defrost, the cooling capacity is reduced by the accumulation thereof. It can be effectively prevented and a stable cooling capacity can be exhibited. Further, as a result, it is not necessary to set the off-cycle defrost time with an excessive margin, and the overall defrost efficiency is significantly improved.

In the above embodiment, the heating means (50)
As means, a means (hot gas bypass passage (10) and drain pan heater (11)) for bypassing hot gas to the evaporator (4) is provided, but the present invention is not limited to such an embodiment. A means for heating the evaporator (5) by an electric heater or the like may be provided.

[0038]

As described above, according to the invention of claim 1, as the defrosting operation control device of the refrigerating device for the container which is installed in the refrigerator, the intake air temperature of the evaporator or the blowout When the air temperature is lower than the specified temperature value, heating defrosting is performed to heat the evaporator with hot gas, etc., while when the intake air temperature of the evaporator is higher than the specified temperature value, the compressor is stopped and only the evaporator fan is operated. Since it is designed to perform off-cycle defrosting, the defrosting operation can be performed according to the operating state of the container refrigeration system and the type of cargo that have various operating modes, and the power consumption can be reduced without impairing the defrosting function. It can be reduced.

According to the invention of claim 2, in the invention of claim 1, the higher the intake air temperature, the shorter the off-cycle defrost time is switched to. Therefore, the temperature inside the refrigerator, that is, the amount of the air heat source is changed. A corresponding off-cycle time can be taken, wasteful defrost after melting of frost can be suppressed, and defrost efficiency can be improved.

According to the invention of claim 3, in the invention of claim 1 or 2, when the amount of frost formation is large, the operation interval between the defrosting operation and the next defrosting operation is shortened and the amount of frost formation is small. Since the operation interval is switched to be longer in the range, it is possible to prevent the cooling capacity from being lowered due to an excessive amount of frost formation.

According to the invention of claim 4, the above-mentioned claim 1,
In the invention of 2 or 3, since the air volume of the evaporator fan is set to operate at a high air volume during the defrosting operation by off-cycle defrost, the heat exchange amount between the intake air and the frost formation of the evaporator can be increased. Therefore, the defrost operation time can be shortened.

According to the invention of claim 5, the above-mentioned claim 1,
In the invention of 2, 3 or 4, when the off-cycle defrost is continuously performed a predetermined number of times or more, the heating defrost is forcibly performed regardless of the suction air temperature, etc. When the above occurs, it is possible to effectively prevent the reduction of the cooling capacity due to the accumulation, and it is possible to exhibit a stable cooling capacity, and it is possible to reduce the margin of the off-cycle defrost time. The defrosting efficiency of can be greatly improved.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of the invention.

FIG. 2 is a vertical cross-sectional view showing the structure on the outside of the refrigerator of the container refrigeration apparatus according to the embodiment.

FIG. 3 is a vertical cross-sectional view showing the structure inside the refrigerator of the container refrigeration apparatus according to the embodiment.

FIG. 4 is a flowchart showing the contents of the main flow of the controller.

FIG. 5 is a flowchart showing a sub-flow of off-cycle defrost control.

FIG. 6 is a flowchart showing a sub flow of hot gas defrost control.

[Explanation of symbols]

1 compressor 2 Air-cooled condenser 4 expansion valve 5 evaporator 5a Evaporator fan 7 Refrigerant circuit 50 heating means 51 Defrosting operation control means 52 Defrosting time switching means 53 Operation interval switching means 54 Air volume control means

Claims (5)

[Claims] 1. A refrigerant circuit (7) comprising a compressor (1), a condenser (2), an expansion valve (4), and an evaporator (5) provided with an evaporator fan (5a), which are sequentially connected. A container refrigeration system in which the evaporator (5) is installed in a refrigerator, and heating means (50) for heating the evaporator (5)
A blower temperature detecting means (Ths or Thr) for detecting the temperature of the intake air temperature or the blown air temperature of the evaporator fan (5a), and the blower temperature detecting means (Ths or Thr) according to a defrosting command. When the detected intake air temperature or blown air temperature is lower than a predetermined temperature value, heating defrosting for heating the evaporator (5) by the heating means (50) is performed, while the intake air temperature or blown air temperature is a predetermined temperature value. In the above case, the compressor (1) of the refrigerant circuit (7)
Defrosting operation control means (51) for controlling to perform off-cycle defrost for stopping the operation of the evaporator and operating the evaporator fan (5a). . 2. The defrosting operation control device for a container refrigerating apparatus according to claim 1, wherein the higher the suction air temperature is, the higher the defrosting is in accordance with the suction air temperature detected by the blower temperature detection means (Ths or Thr). A defrosting operation control device for a container refrigeration system, comprising defrosting time switching means (52) for setting the off-cycle defrosting time by the operation control means (51) to be short. 3. The defrosting operation control device for a container refrigeration system according to claim 1 or 2, wherein the defrosting operation interval by the defrosting operation control means (51) is short during pull-down, and the defrosting operation interval during in-range. A defrosting operation control device for a container refrigeration system, characterized in that it comprises an operation interval switching means (53) for setting so as to lengthen the temperature. 4. A defrosting operation control device for a container refrigeration system according to claim 1, 2 or 3, wherein the evaporator fan (5a) has an air volume switching function and is turned off by the defrosting operation control means (51). A defrosting operation control device for a container refrigeration system, comprising an air volume control means (54) for controlling the air volume of the evaporator fan (5a) to a high air volume during cycle defrost operation. 5. The defrosting operation control device for a container refrigerating device according to claim 1, 2, 3 or 4, wherein the defrosting operation control means (51) continuously performs defrosting operation by off-cycle defrost. A defrosting operation control device for a container refrigeration system, characterized in that the defrosting operation for the next time is forcibly switched to the defrosting operation by heating defrost when the operation is performed more than the number of times.