JPS5913875A - Defrosting controller - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (a) Technical field The present invention is directed to the elimination of multiple evaporators installed in refrigeration equipment such as refrigerated showcases and refrigerators that have different operating temperatures, or in refrigeration equipment such as frozen showcases and freezers. The present invention relates to a defrosting control device that performs frost control in a centralized manner.

(B) Conventional technology and problems Conventionally, defrosting control of evaporators installed in refrigeration equipment or freezing equipment with different operating temperatures has been performed for each operating temperature range, for example, when the internal temperature is as low as 120°C. , 0°C, and 5°C, and defrosting control equipment has been used to control the removal of evaporators for each temperature range. In addition, defrosting control defrosts each evaporator at predetermined intervals, adjusting the load to the worst value in advance for each temperature zone.For example, in an open showcase where the internal temperature is 0℃ Then, the temperature of the items inside the refrigerator will rise every 4 hours, and in the case of a flat refrigerator case, approximately every 12 hours before and after the supermarket in which the case is installed opens, due to blockage of the evaporator due to frost formation. Defrosting has been carried out by determining defrosting intervals within a range that does not cause product deterioration. Furthermore, changing the defrosting interval based on seasonal changes in the amount of rice planted is very troublesome when using a mechanical timer such as a Parabon timer, so defrosting is performed at the same intervals throughout the year.

Therefore, in order to determine the defrosting interval according to the worst load of a showcase equipped with an evaporator, for example, the defrosting interval must be determined based on the summer when the amount of frost is large. Even in the winter when the temperature is small, defrosting is carried out wastefully at the same intervals as in the summer, resulting in an increase in power consumption due to defrosting, and changes in the set value of the vibration isolation interval due to differences in the set value of the extractor internal temperature. Since the method is rough, it has the drawback that it is not possible to perform optimal defrosting for each evaporator.

(c) Purpose of the Invention The purpose of the present invention is to supply an optimal defrosting method to multiple evaporators of refrigeration equipment or freezing equipment using one defrosting control device, perform defrosting according to ambient conditions, and store The objective is to reduce overall power consumption while maintaining the freshness of the products.

b) Main points of the invention A first defrosting means that defrosts the evaporator at predetermined time intervals, a second defrosting means that defrosts the evaporator at scheduled defrosting start times based on the predicted accumulated time, and an actual defrosting means. The above defrosting method is suitable for a plurality of evaporators installed in a refrigeration facility or a freezing facility, and is equipped with a third defrosting means that defrosts when the waiting time reaches the unloading start time. Defrosting is performed by selecting from three methods.

(E) Practical Example of the Invention Figures 1 to 10 show an embodiment of the present invention. Figure 1 shows a refrigerant circuit and an electric circuit for refrigeration equipment and freezing equipment. First, the refrigerant circuit will be explained. The first compressor (1) includes a first condenser (1a), an expansion valve (2), and a first evaporator (3).
The series circuit with A) is connected to form the refrigerant circuit of the refrigeration equipment. The second compressor (4) also includes a second condenser (4a) and a second valve opening/closing device (such as a liquid electromagnetic valve).
5B), an expansion valve (2), and a second evaporator (313) are connected, and a third valve opening/closing device (5C), an expansion valve (2), and a third evaporator are connected in parallel to the series circuit. A series circuit with the evaporator (3C) is connected. (6) is a third compressor, and like the second compressor (4), it has a third condenser (6a) and fourth, fifth, and sixth valve opening/closing devices (5D) (5E) ( 5F
), expansion valve (2! (21 (21, 4th, 5th, 6th
The evaporators (3D)' (3E) (3F) constitute a series circuit and are connected in parallel. Note that the second...fifth evaporators (5B)...(5F) are installed in the refrigeration equipment. Next, the electric circuit will be explained.

(The sword is a defrosting control device, which is connected to the first electrical box (7A) that controls the operation of the first compressor (1), and also connected to the second...fifth valve opening/closing device (5B). )...(5F)
K connection, when each valve opening/closing device is open, it is assumed that liquid refrigerant is flowing through the corresponding evaporator, and the defrosting control device (7
), and when it is closed, it is assumed that liquid refrigerant is not flowing through each evaporator, and a signal is given to the defrost control device (power). The second and third electrical boxes (7) control the operation of the compressor (41 (61)
B) Connected to (7C).

The first evaporator (3A) has an internal temperature set value of approximately 20
The second and third evaporators (3B) (3C) are refrigeration equipment with a set internal temperature of about 0°C ± 2°C, such as an evaporator installed in a freezer showcase. For example, in an evaporator installed in a low-temperature showcase for storing meat, the fourth, fifth, and sixth evaporators (3D) (3E) (3F)
is an evaporator installed in a refrigerating facility with an internal temperature set value of around 7° C., for example, a refrigerated showcase for storing vegetables.

FIG. 2 shows the time change in the amount of frost formed on the evaporator by the first defrosting means called the fixed timer method incorporated in the defrosting control device (7), and shows the change over time in the amount of frost formed on the evaporator at predetermined time intervals, for example, for 24 hours. Scheduled defrosting time (T1)...(T,) by timer
is set, and a defrosting output is issued from the defrosting control device (7) at each scheduled time. The above-mentioned frost formation represents the cumulative operating time of the compressor, and even when the operating time of the compressor becomes longer due to a sudden increase in cooling load, the defrosting output is reliably maintained at predetermined time intervals. Since the defrosting signal is outputted at predetermined time intervals and even when the defrosting scheduled time arrives even when the defrosting signal is extremely rare, there is a drawback that unnecessary defrosting is performed. Therefore, the first gap means is such that the temperature inside the refrigerator is, for example, -
Refrigerating showcases that are extremely low at 20 degrees Celsius, and the evaporator is not naturally defrosted when the valve opening/closing device is closed, so the evaporator must be forced to gradually open periodically by, for example, energizing the electric heater installed in the evaporator. The first evaporator (3A) shown in FIG. 1 is defrosted by the first defrosting means.

FIG. 3 shows the defrosting control device (similar to the first defrosting means).
This is a block circuit diagram of the second defrosting means called the step demand method incorporated in 7), which includes a differential prediction circuit (8A) that outputs a deloading signal by the professional method and a defrosting signal by the accumulation prediction method. An accumulation prediction circuit (8B) that outputs, a first OR circuit (9) into which the outputs of these defrost request circuits are input, and an internal timer that outputs to the respective prediction circuits (8A) (8B) at set times. A circuit (hereinafter referred to as an internal timer) aQ, a manual switch circuit (1, 2, and a first
It is composed of an OR circuit (9) and a second OR circuit 0 to which the output of the switch circuit θ is input. FIG. 4 is a schematic diagram of a control circuit that controls the operation of the second compressor (4) including the switch circuit (12) and the defrosting electric heater 04, in which the DC power supply terminal (151 is connected to the excitation winding of the electromagnetic contactor Oe). line α
A first npn (npn) transistor (hereinafter referred to as "T") to which a signal is applied from the first AND circuit (0) is connected to the base.A switch circuit (
121 is a switch connected to the power terminal (+51), for example, a manual switch 021, and a second Tr (A) connected in parallel to a resistor (first Tr Q8), and a pace connected to the resistor (R). C!υ is the normally closed switch of the electromagnetic contactor o6), which is connected in a ring with the compressor (4) and the AC power supply (2), and the normally open switch (c) is the electric heater. 04) and an AC power source (2) in a ring.

The operation of the block circuit will be explained below. Internal timer (
10) outputs at the set time, at least one of the respective defrost request circuits (8A) (8B) outputs an output, and when the first OR circuit (9) outputs, the second OR circuit (9) outputs an output.
A defrosting signal is output from the OR circuit θJ.

Also, for example, if the internal timer 〇G malfunctions, the first OR circuit (
9) does not output and you want to defrost immediately, turn on the manual switch 021 to turn on the second Tr (21), energize the excitation winding (17), and close the normally closed switch (21).
) is opened, the normally open switch ) is closed, the compressor (4) is stopped, and the electric heater Oa is energized to perform defrosting.

The micromolecule measurement method and the accumulation prediction method will be explained below. The micromolecular measurement method is a method that predicts the cumulative time after a predetermined time by assuming that the rate of change in the cumulative time from a certain time to a predetermined time, e.g., one hour, continues for a predetermined time from that time. , the cumulative time at this time is N(5), this τ is the cumulative time one hour before the time N (a), this τ is the time after a predetermined time from the time and τ is +1, and the cumulative time at this time is If the predicted amount of is N(A), then N(A5-"E-C") -flW x (rk
+l-rk) + N(a)-(a).

Figure 5 shows an example of the micromolecule measurement method. For example, it is a time characteristic diagram of the cumulative time difference between the flow time of the liquid refrigerant to the second evaporator (3B) and the flow 1 (flow time). The axis shows cumulative time, the horizontal axis shows elapsed time, and the horizontal axis shows the specified time ('ro).
First... fourth scheduled defrosting times (hereinafter referred to as times) are set for each interval. The origin ('rl is the end of the previous defrosting operation, and the cumulative time is zero at this time. When the predetermined time elapses and the first time (T, ) comes, the point ('rl) that is one hour before this first time ( 1゛-first cumulative time (τal)
and the cumulative time at the first time.
The cumulative time at time (T2) is predicted. This first
Using equation (a), the predicted cumulative time (τb) of
]-τ='l'. Therefore, τb = 7- x '1'. It is expressed as 10τ8, which is smaller than the cumulative defrosting start time (τ),
At this time, the differential molecular measurement circuit (8A) does not output any output. Similarly, when the second time hits, the cumulative time at the third time is predicted. The second cumulative time at the second time ('I'2) (τb), the cumulative time one hour before from the second time ('I'2) (T2), the second predicted cumulative time (τC)
Then, this predicted cumulative time is ′ τb−τb] ・・−−′−′ i −−X Go・ ”−・
b, which is longer than the cumulative defrosting start time (τ), so the micromolecule measurement circuit (8N) is activated at the second scheduled time (T, )
is output, and a defrost signal is output from the defrost control device (7).

Next, the accumulation prediction method will be explained. The accumulation prediction method is a method that predicts the cumulative time at the next scheduled time by assuming that the rate of change in the cumulative time from a certain time to the previous scheduled time will continue until the next scheduled time. τ
1, the cumulative time at this time is N (Bl, the previous scheduled time τ - 1, the cumulative time at this time is NFC), the next scheduled time is set to τ → 1, the predicted amount of cumulative time at this time is N(B
), then N m = N (B) Judan3i-N (
C) ×(·k+1−rk)··°(·)rk −1 to −1. Here, if the time from the previous scheduled time τ -1 to the scheduled time τk is TI+the time from the scheduled time τk to the next scheduled time τ -)], then T2 is expressed as Equation (b).

FIG. 6 is a time characteristic diagram of the cumulative time difference between the time when liquid refrigerant flows to the third evaporator (3C) and the time when it does not flow, showing an example of the accumulation prediction method. Similarly, the vertical axis and the horizontal @ are taken, and the first...fourth times (T1)...('r4) are set on the horizontal axis at intervals of a predetermined time (1゛.). When the predetermined time ('".) has passed from the origin (0) where the cumulative time is zero at the end of the previous defrosting operation and the first time (T1) is reached, the cumulative time up to this first time (
The cumulative time at the second time (T2) is predicted based on τ, ). This first predicted cumulative time (τ,) is =2τ using equation (c).

Since it is smaller than the cumulative defrosting start time (τ),
At this time, the accumulation prediction circuit (8B) does not output.

When time passes and the second time (T, ) comes, the third time (
Predict the cumulative time at T3). Second time (T2
), the second cumulative time (T2) and the third cumulative time (T
When the second predicted cumulative time (τ,) in 3) is subtracted, it is expressed as =2τ2−T1, which is smaller than the defrosting start cumulative time (τ), so the storage prediction circuit does not output at this time. Time has passed and the third
When the time (T3) comes, the third predicted cumulative time (T3) at the fourth time ('1.'4) is predicted.

If the cumulative time at the third time is (T3), then the third predicted cumulative time (T3) is =2τ, -ten.

Since the defrosting start cumulative time (τ) is exceeded, the accumulation prediction circuit (8B) outputs an output at this third time.

Below, based on Fig. 7, the frost formation on the second evaporator (3B) by the second weight removal method, that is, the time during which the liquid refrigerant flows to the second evaporator (B) and the time when it does not flow. Explain the temporal change in the cumulative time of the lily with time.

At predetermined time intervals, for example, every two hours, the first...third scheduled removal time (hereinafter referred to as time) ('r, XT2
) (1, '3) fJ'' - Set by the internal timer, and after the third time (T3), a defrost prohibition zone (S ).Therefore, there is no scheduled removal time set in this prohibited zone, and a third time (T
, ), a fourth time (T4) is set approximately 4 hours after
A fifth time (T,) is set two hours later.

Further, the third evaporator (3C) also operates in the block circuit (7) provided in the defrosting control device (7) in the same way as the second evaporator (3B).
) is controlled by When the internal timer 〇(2) outputs at the first time (T1), the micromolecule measurement circuit (
When both the circuit 8A) and the accumulation prediction circuit (8B) do not output, the second OR circuit (13) does not output, and the division 1i signal is not output.As time passes, at the second time (T2) When the internal timer (1ω) is output, each prediction circuit (
When at least one of prediction circuits 8A) (813) outputs an output, a defrosting signal is output to the electrical box (7B), the second compressor (4) is stopped, and the second and third evaporator (
3B) (3C) is divided by 1 by the heat source of an electric heater, for example.
11, and the cumulative time becomes zero. When further time passes and the third time (T, ) is reached, the internal timer (101) outputs, and each prediction circuit (8A) (8B) calculates the cumulative value at the fourth time (T4) after the prohibited zone (S). When the time is predicted and at least one of the prediction circuits outputs an output, a defrosting signal is output and defrosting is performed, and the cumulative time becomes zero again.As time passes, the sardine prohibition zone (S) is reached. End, fourth time (T
4 ), each prediction circuit (8A) (8, 8) again predicts the cumulative time of the fifth time (T, ), and both prediction circuits (
When 8A) and (8B) determine that the cumulative time at the fifth time does not exceed the upper limit cumulative time (goods) and the block circuit of the third evaporator (3C) also does not output, the defrosting signal is not output. When further time passes and the fifth time (T, ) is reached, the cumulative time of the next time is predicted, and when the defrosting signal is output, the second
, the third evaporator (313) (3C) is defrosted and the cumulative time becomes zero. Therefore, for example, in a low-temperature showcase where the internal temperature at which the frost melts when no liquid refrigerant is flowing through the evaporator is around 0°C, defrosting is performed based on the cumulative time, which makes it possible to reduce the number of defrosting operations. This is most preferable because a forbidden zone can be provided, and as described above, the second and third evaporators (3B) (3C) are defrosted by the second defrosting method. Here, when the cumulative time of the second evaporator (3B) and the cumulative time of the third evaporator (3C) change over time as shown in FIG. ), when it is predicted that the accumulated time of at least one of them at the next scheduled defrosting time (t2) will exceed the upper limit M, both evaporators (3B) (3C) are divided by 1.
11 will be performed.

Similarly to the first and second defrosting means, FIG. 9 shows the temporal change in cumulative time based on the third defrosting means called the complete demand method, which is incorporated in the defrosting control device. A scheduled defrosting start time is set in this third gourd removal means, and when tc <, the actual cumulative time that gradually increases with the passage of time reaches the cumulative time upper limit (Nn), the weight removal output (^) ( A) is controlled by the defrost control device for a predetermined period of time.

The defrosting button is output; therefore, the third defrosting means is
Even if the rate of increase in the cumulative time increases over time, the defrosting signal is not output until the cumulative time reaches the cumulative upper limit time MK. This is suitable for defrosting an evaporator installed in a refrigerated case for storing vegetables, for example, where the internal temperature setting value is 5 to 10° C. so that natural defrosting can proceed reliably. Therefore, defrosting of the fourth, fifth, and sixth evaporators (3D), (3E, and 3F) in FIG. 1 should be performed by the third defrosting means. In addition, similarly to the second defrosting means, the fourth, fifth, and sixth valve opening/closing devices (5T3) (5F, ) (5
F) When the cumulative time reaches the maximum limit based on the longest cumulative time, that is, when any one cumulative time reaches the upper limit, the defrosting control device (7) ) outputs a defrost signal to the lower 3rd electrical box (7C) that controls the operation of the 3rd compressor (6), the 3rd compressor (6) stops operating, and the 4th and 4th 5. Sixth evaporator (
Liquid refrigerant is no longer supplied to 3D), (3E), and (3F), and the respective evaporators are removed from the register.

Figure 10 shows the discharge air temperature of the second evaporator (3B) in Figure 1, which is controlled to be removed by the second defrosting means, the operation and stop of the second compressor (4), and the opening and closing of the second valve. It shows the change over time in the opening and closing of the device (hereinafter referred to as the second valve) (5B), where (Hl) is the upper limit set temperature, (L+) is the lower limit set temperature, (H2) is the upper limit temperature increase, (L,) is the lower limit temperature, and when the defrost control device (7) outputs a defrost signal when the second valve (5B) is closed, the second compressor for a predetermined time as shown in (25) (4) is stopped for a predetermined time, e.g.
Electric heater 04 provided in the second evaporator is energized at the same time when the 5-minute liquid refrigerant is not supplied and the defrost signal is output.
) The discharge air temperature gradually rises due to the heat generated by the discharge air, and exceeds the upper limit set temperature (I■, ). Then, the second valve (5B) opens, but since the second compressor (4) is stopped, the liquid refrigerant is not circulated, and the discharge temperature continues to rise, causing the second evaporator (3B) to open. )
will be expelled from the register. The discharge temperature exceeds the upper limit temperature increase and further increases, and when a predetermined period of time has elapsed since the second compressor (4) stopped, the second compressor (4) stops operating due to the output from the defrost control device (7). resume. From the time (26) when this discharge air temperature exceeds the upper limit set temperature 011) until the time (27) when the second compressor resumes operation, the second valve (5B)
is open, but since the liquid refrigerant is not being supplied to the second evaporator (3B) and defrosting is being performed, the first
As a singular value (28) of , the valve is assumed to be closed and is included in the cumulative time as shown by the dotted line. The discharge air temperature decreases, and the discharge air temperature continues to rise and fall due to the opening and closing of the second valve (51), and when the time is reached and the second valve (5B) is closed, forced intermittent operation starts. When the second compressor (4) stops operating, liquid refrigerant is not supplied to the second evaporator (3B), so the discharge air temperature gradually increases (1
2. When the upper limit temperature setting (■II) is exceeded, the second valve (5B
) becomes open. However, the second compression (4) is stopped and liquid refrigerant is not supplied to the second evaporator (3B).
, C, from this point in time 01) until the forced intermittent operation time ends and the second compressor (4) resumes operation, the second valve (
513) is included in the cumulative time as being closed. When a predetermined period of time, for example, 20 minutes has passed since the forced intermittent operation started, the forced intermittent operation ends and the second compressor (4)
begins operation, and the second singular value (32 also ends,
Thereafter, it is assumed that the second valve is open and liquid refrigerant is flowing. Thereafter, the discharge air temperature gradually decreases, and the set temperature is narrowed, and the discharge air temperature continues to rise and fall. Therefore, a defrosting means suitable for a plurality of evaporators with different operating temperatures provided in refrigeration equipment and freezing equipment is selected from the first, second, and third defrosting means incorporated in the defrosting control device in advance. The first gap means is suitable for evaporators installed in refrigeration equipment that generates a large amount of frost, and the second defrosting means uses a micromolecule measurement method and an accumulation prediction method, so it can be removed easily. In the 'lf4 prohibited zone, the cumulative time exceeds the defrosting start cumulative time. In other words, when the actual defrosting start time is predicted to be in the defrosting prohibition zone, defrosting is performed before this time, for example, during the busy season when customers are crowded.
An increase in product temperature due to No. 1 can be avoided in advance.

In addition, since the second and third gap means defrost based on cumulative time, for example, in winter when the outside air temperature is low, the number of defrosts is small, and in summer when the outside air temperature is high, the number of defrosts is increased. Defrosting can be performed according to the season without adjusting the number of times defrosting is performed per day. Since defrosting is performed based on a long evaporator, it is possible to defrost all evaporators reliably. Also, since it has a manual switch for forced defrosting, it can be used in the event of a malfunction of the internal timer, for example. Even when defrosting is no longer performed automatically, defrosting can be performed manually.

Furthermore, since defrosting by the first, second, and third defrosting means is performed independently without being influenced by each other, defrosting by each defrosting means is reliably performed.

(f) Effects of the invention The defrosting control device that controls defrosting has first, second, and third defrosting means, and it is possible to select the most suitable defrosting means for each evaporator from these three means. Moreover, because it uses a prediction method, defrosting can be performed according to ambient conditions such as seasonal changes and an increase in the number of items to be cooled, and the number of times defrosting can be reduced, thereby reducing the temperature rise caused by defrosting. While maintaining the freshness of products stored in refrigerators and freezers, it is possible to reduce compressor operation time, reduce power consumption, and reliably prevent evaporator clogging due to encroachment. can.

[Brief explanation of the drawing]

1 to 10 are drawings shown as an embodiment of the present invention, in which FIG. 1 is a refrigerant and electric circuit diagram, FIG. 2 is a cumulative time transition diagram of the first defrosting means, and FIG. A block circuit diagram of the second defrosting means, Fig. 4 is a schematic diagram of the control circuit, Fig. 5 is a time course diagram of cumulative time by differential molecular measurement, and Fig. 6 is a time course diagram of cumulative time by accumulation prediction method. , Fig. 7 is a time course diagram of the cumulative time by the second defrosting means, Fig. 8 is a time course chart of the cumulative time related to the evaporator of the third and fourth measures, and Fig. 9 is a time course diagram of the cumulative time related to the third defrosting means.
Fig. 10 is a time course chart showing the cumulative time by the gap means, and Fig. 10 is a time course chart showing the discharge air temperature and singular values. (7) Defrosting control device, (7) Block circuit, (8A) Differential prediction circuit, (8B) Accumulation prediction circuit, (9) First OR Circuit, Ql...internal timer circuit, (1ri...manual switch circuit, (13)
...Second OR circuit. Agent Patent Attorney Shizuka Sano Judgment 1.7j'・＼-6
-1-

Claims (1)

[Claims] 1. A first defrosting means that defrosts the evaporator at predetermined time intervals, a scheduled defrosting start time is set at predetermined time intervals, and a cumulative flow of liquid refrigerant to the evaporator is provided. Using either the time or the cumulative time of the time difference between the time when liquid refrigerant power 1 flows and the time when it does not flow, the evaporator with the longest predicted cumulative time, which is calculated by adding the predicted time to the cumulative time, is used as a reference, and the prediction is made based on the evaporator with the longest predicted cumulative time. When it is predicted that the cumulative time will reach the defrosting start time, divide the amount by 1 yen at the scheduled defrosting start time. The evaporator with the longest cumulative time is used as the reference point, and when the actual cumulative time reaches the defrosting start time, the defrosting process is started. It is equipped with 3 defrosting means and 4! Defrosting control device with I' characteristic
1, an accumulation prediction circuit that performs accumulation prediction based on cumulative time, a 10th OR circuit that outputs based on the input from each prediction circuit, and a Maemachi - differential measurement circuit that performs accumulation at a predetermined time. A block consisting of an internal timer circuit that outputs an output to the prediction circuit, and a second OR circuit that outputs a defrosting signal based on the output of the first OR circuit and a switch circuit for forcibly switching to shin removal operation. 2. The defrosting control device according to claim 1, further comprising a circuit.