JPH0367972A - Device for controlling operation of refrigerating apparatus - Google Patents

Abstract

PURPOSE:To prevent freeze in evaporators, when the operation for evaporation simultaneously takes place at all the evaporators, by providing a means for the simultaneous control of operation whereby, when the output of a saturation- temperature detective means indicates that the saturation temperature of refrigerant corresponding to the evaporative pressure has remained lower for a specified time than a fixed prescribed value of saturation temperature, freeze-preventive operation is effected at the evaporators for a certain period of time. CONSTITUTION:When, during the simultaneous operation for evaporation at all the evaporators 7,... (or 12,...), the saturation temperature corresponding to the evaporative pressure on the suction side, detected by a saturation- temperature detective means Sp, has remained lower for a specified time than a fixed prescribed value, a simultaneous operation-controlling means 51 causes freeze-preventive operation to be effected for a certain period of time at all the evaporators 7. Therefore, without involving errors in starting time of freeze which are due to differences in capacity, condition of the use, etc. between respective evaporators 7, the freeze-preventive operation takes place under uniform conditions and accurate prevention of freeze can be effected.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to an operation control device for a refrigeration system equipped with a plurality of evaporators, and in particular, to prevent freezing of the evaporators during simultaneous evaporation operation of each evaporator. Concerning improvements to what was made.

(Prior Art) Conventionally, as disclosed in, for example, Japanese Unexamined Patent Application Publication No. 62-119348, as shown in FIG. Predetermined value T
If TMI continues to be lower than LI (usually a value of about -7°C) for a predetermined period of time (for example, about 10 minutes), it is determined that there is a risk of freezing in the heat exchanger on the user side, and the user side is disturbed. Techniques that attempt to prevent the user-side heat exchanger from freezing by melting frost on the user-side heat exchanger by reducing the amount of heat exchange, such as by blocking the flow of refrigerant to the exchanger, are known techniques. It is.

(Problems to be Solved by the Invention) The above-described antifreeze operation can effectively eliminate accidents such as water leakage caused by freezing of the user-side heat exchanger.

By the way, in particular, in a regenerative air conditioner equipped with a heat storage tank for storing cold heat through heat exchange with the refrigerant in the refrigerant circuit, the refrigerant is simultaneously evaporated in the heat storage coil of the heat storage tank while cooling is being operated indoors. Simultaneous cooling and cold storage heat operation may be performed to store cold heat.

In such a case, if the conventional control device described above is used, even if the heat exchanger on the user side freezes and the amount of heat exchange decreases, the heat storage tank still stores cold heat (for example, ice making operation), so the overall The heat exchange amount does not decrease, and as shown in Figure 6, the liquid pipe temperature TL remains at a value higher than the set value TLI in Figure 5 (e.g. -1°) regardless of whether or not the heat exchanger on the user side is frozen. It will be maintained at a value of about C). Therefore, it is not possible to perform anti-freeze operation in this state, and to perform anti-freeze operation, set the set value TLI to a certain high value (for example, -1°C).
The temperature must be set to a value that is ~2°C higher than the actual value.

However, if such a high setting value T1-1 is provided,
As shown in FIG. 7, the predetermined time (1
A cycle is repeated in which anti-freezing operation is performed frequently for a certain period of time (for example, about 15 to 16 minutes) after normal operation is performed for a period of about 0 minutes (about 0 minutes).

As a result, the predetermined time TMl for such determination is usually
Since this is set to be short, there is a problem in that the time during which the anti-freeze operation is performed becomes longer, which impairs the feeling of air conditioning during normal cooling operation.

The present invention has been made in view of the above, and its purpose is to perform evaporation based on the refrigerant state quantity common to each evaporator during simultaneous evaporation operation of a plurality of evaporators such as a user-side heat exchanger and a heat storage coil. To perform anti-freezing operation without causing deterioration of the feeling of air conditioning by performing anti-freezing operation.

(Means for Solving the Problems) In order to achieve the above object, the solving means of the present invention consists in making a determination for performing antifreeze operation based on the evaporation pressure equivalent saturation temperature in the suction line.

Specifically, as shown in FIG. 1, a pressure reducing mechanism (6 or 14) and an evaporator ( 7 or 12) connected in series and connected in parallel to form a closed circuit.

As an operation control device for the refrigeration system, a saturation temperature detection means (Sp) is arranged on the suction side of the main refrigerant pipe (9) and detects the saturation temperature corresponding to the evaporation pressure of the refrigerant, and each of the evaporators (7 or 12) During the simultaneous evaporation operation of . Simultaneous operation control means (
51).

A second solution is that in the first solution, the refrigeration system is a regenerative air conditioner equipped with a heat storage cypress (11) that stores a heat storage medium capable of storing cold heat through heat exchange with a refrigerant, and At least one of the evaporators is used as a heat storage coil (12) that stores cold heat in the heat storage sleeve through heat exchange with the heat storage medium, and the other evaporator is used as a user-side heat exchanger (7).

Then, the simultaneous operation control means (51) is activated in the user-side heat exchanger (7) when the saturation temperature corresponding to the evaporation pressure of the refrigerant continues to be lower than the saturation temperature set value for a predetermined period of time during the simultaneous operation of cold storage heat and cooling. The system is controlled to perform anti-freeze operation.

In addition to the second solution, the third solution includes an evaporation temperature detection means (T11ρ) that individually detects the evaporation temperature of the refrigerant in the utilization side heat exchanger (7), and a utilization side heat exchanger (T11ρ). 7) During normal cooling operation in which the refrigerant evaporates only, the evaporation temperature in each user-side heat exchanger (7) is lower than a predetermined evaporation temperature setting value according to the output of the evaporation temperature detection means (Thl). If this continues for a predetermined period of time, the heat exchanger on the user side (7)
Normal cooling control means (52) that performs antifreeze operation in
The saturation temperature set value is set higher than the evaporation temperature set value by a predetermined temperature.

(Function) With the above configuration, in the invention of claim (1), during the simultaneous evaporation operation of each evaporator (7 or 12),... When the evaporation pressure equivalent saturation temperature becomes lower than a predetermined set value for a predetermined period of time, the simultaneous operation control means (51) performs antifreeze operation in each evaporator (7) for a predetermined period of time.

Therefore, the antifreeze operation is performed under regular conditions, and accurate antifreeze is performed without causing errors in the start time of freezing due to differences in the capacity of each evaporator (7) or usage conditions. Become.

In the invention of claim (2), in the invention of claim (1), the refrigeration device is a regenerative air conditioner, and at least one of the evaporators or a thermal storage coil disposed in the thermal storage W (11) is provided. (12), and the other evaporator is the user-side heat exchanger (7), the user-side heat exchanger (7) does not perform cooling operation, and the refrigerant is evaporated in the heat storage coil (12). Heat storage) (ff (11) during simultaneous operation of cold storage heat and air conditioning for storing cold heat such as ice making, etc., by the simultaneous operation control means (51),
When the evaporation pressure equivalent saturation temperature detected by the saturation temperature detection means (Sp) is lower than a predetermined set value, the user side heat exchanger (7) is controlled to perform antifreeze operation.

Therefore, despite the extreme difference in the capabilities and usage conditions of the user-side heat exchanger (7) and the storage coil (11) in such a regenerative air conditioner, the invention of claim (1) above does not solve the problem. It is possible to effectively demonstrate the effect.

In the invention of claim (3), in the invention of claim (2) above, during normal cooling operation, the simultaneous operation control means (51)
Normal cooling control means (52
), the 7-day tube sensor (T
When the limb tube temperature TL detected in hl) becomes lower than a predetermined evaporation temperature setting value, the user-side heat exchanger (7)
Freeze prevention operation will be carried out. Therefore, the saturation temperature setting value for performing anti-freezing operation during cold storage heat and cooling operation at the same time can be set higher by a predetermined temperature than the evaporation temperature setting value for performing anti-freezing operation during normal cooling operation. Since freezing in the user-side heat exchanger is reliably prevented during cold storage heat and cooling operations at the same time, deterioration of the air conditioning feeling due to frequent antifreeze operations during normal cooling operations is prevented.

(Example) Hereinafter, an example of the present invention will be described based on the drawings from FIG. 2 onwards.

The second figure shows the overall configuration of the air conditioner according to the first embodiment, in which a plurality of indoor units (A), (B), ... are connected to the outdoor unit I-(X). This is a so-called multi-type air conditioner.

In the above outdoor unit (X), (1) is a compressor, (
2) is a four-way switching valve that switches as shown in the solid line in the figure during cooling operation and as shown in the broken line in the figure during heating operation;
) is an outdoor heat exchanger as a non-source side heat exchanger that functions as a condenser during cooling operation and as an evaporator during heating operation, and (4) adjusts the refrigerant flow rate during cooling operation and reduces the pressure of the refrigerant during heating operation. (5) is a receiver for storing condensed liquid refrigerant; and (8) is an accumulator for removing wave components in the suction refrigerant.

On the other hand, each indoor unit (A), (B), ... has the same configuration, and (6) is an indoor electric expansion valve that functions as a pressure reduction mechanism during cooling operation and adjusts the refrigerant flow rate during heating operation; (7) is an indoor heat exchanger that functions as an evaporator during cooling operation and as a condenser during heating operation.

The above-mentioned devices (1) to (8) are sequentially connected to each other through refrigerant piping (9) so that the refrigerant can flow] 1.The heat pump functions to release blue heat to the indoor air through heat exchange with the outdoor air. A main refrigerant circuit (10) is constructed.

Furthermore, a heat storage unit (Y) is arranged in the device to store cold heat and warm heat through heat exchange with the refrigerant flowing through the main refrigerant circuit (10), or to utilize the stored cold heat and warm heat. has been done. In the heat storage Uni-So1-(Y), 01
) is a heat storage tank that stores water (W), which is a heat storage medium that can store cold heat, and (12) is a heat storage tank that is placed in the heat storage tank (11) and is used to exchange heat between the water (W) and the refrigerant. A heat exchanger between the storage heat exchanger (12) and the relative line (9a) between the outdoor electric expansion valve (4) and the indoor electric expansion valve (6) of the main refrigerant circuit (10). , the first branch pipe (13a) and the second branch pipe (13b) are connected in order from the indoor electric expansion valve (6) side so that refrigerant can flow therethrough. The first branch pipe (13a) has a storage μm as a cold storage heat decompression mechanism that depressurizes the refrigerant when storing cold heat in water (W).
An electric expansion valve (14) is interposed, and the second branch pipe (13)
b)] 2 is equipped with a second opening/closing valve () which opens and closes the second branch pipe (], 3b).
5) is provided.

In addition, the first on-off valve (15) of the second branch pipe (13a)
) and the intermediate piping between the storage heat exchanger (12) and the main refrigerant circuit (
10) The gas line (9b) is the third branch pipe (13c)
The third branch pipe (], 3c) is connected to a second branch pipe (], 3c) for opening and closing the branch pipe (], 3c).
An on-off valve (16) is also provided.

On the other hand, the above-mentioned No. 1 of the seventh line (9a) of the main refrigerant circuit (10). 2 with the second branch pipe (13a), (], 3b)
A flow control valve (17) for variably adjusting the flow rate of the refrigerant is interposed between the two joints.

In other words, the above 6 valves (2), (4), (6)
(14), (1,5), (16), (17
), or by adjusting the degree of opening, the refrigerant ring route is switched according to each operation mode.

Also, the device is equipped with sensors, (Thw)
is placed in the water of the heat storage tank (11), 3 is a water temperature sensor that detects the water temperature TV, and (T ha) is placed at the air suction port of the outdoor heat exchanger (3), and is used to detect the outside air temperature Ta. Sensor, (Thi) family line (9a)
The cooling population sensor (Tho) is located on the upstream side during cooling operation at the junction with the second branch pipe (13b) of the liquid line (9a), and (Tho) is the cooling population sensor at the junction with the first branch pipe (13a) of the liquid line (9a). Cooling outlet sensor located downstream during operation,
(Th, 1?).

... is arranged on the wave tube side of each indoor heat exchanger (7), ..., and detects the liquid pipe temperature T4) as the individual evaporation temperature of each indoor heat exchanger (7) during cooling operation. A tube sensor (T hs) as an evaporation temperature detection means is placed in the suction line (9d), and a suction tube sensor (S p) for detecting the suction tube temperature is placed in the gas line (9d). , high-pressure TQ as a saturation temperature equivalent to condensing pressure during the heating cycle, and each indoor heat exchanger (7) that functions as an evaporator during the cooling cycle, ... and a regenerative heat exchanger (1).
2) is a pressure sensor as a saturation temperature detection means for detecting the low pressure Tc which is the saturation temperature corresponding to the average evaporation pressure.

4 During normal cooling operation, as shown by the arrow in Figure 2, the four-way switching valve (2) switches as shown by the solid line in the figure, the outdoor electric expansion valve (4), the flow rate control valve (1, 7), Indoor electric expansion valve (
6),... are opened and all other valves are closed, and the refrigerant condensed in the outdoor heat exchanger (3) circulates only through the main refrigerant circuit (10), Electric expansion valve (6
)1..., evaporated in each indoor heat exchanger (7),... and returned to the compressor (1).

And while cooling the room indoors, the heat storage cypress (here)
During normal cooling and cold storage heat simultaneous operation, the heat storage electric expansion valve (14
) and the second on-off valve (16) open, and the outdoor heat exchanger (3) opens.
A part of the liquid refrigerant condensed in the main refrigerant circuit (10) bypasses and flows into the first branch pipe (13a), is depressurized by the heat storage electric expansion valve (14), and is transferred to the heat storage heat exchanger (12). It is evaporated and circulated back to the compressor (1). At this time, water (W), which is a heat storage medium, is made into ice by exchanging heat with a refrigerant in the heat storage heat exchanger (12), and cold heat is stored.

Here, the control contents during the normal cooling and cold storage heat simultaneous operation will be explained based on the flowchart 1 in FIG. In step S3, the low pressure Tc as the average evaporation pressure equivalent saturation temperature detected by the pressure sensor (Sp) is set to a predetermined saturation temperature set value Tel [=-2,5-(FT-30)
xQ, 035] (However, FT is an inverter (1
8), and if the low pressure Te or the saturation temperature set value Te1 is higher than the low pressure Te or the saturation temperature set value Te1, the indoor thermo-on is permitted to perform cold storage heat and cooling simultaneously, while the low pressure Tc is at the saturation temperature. When it becomes lower than the set value Tel, the process moves to step S4, and the timer] (set to 30 seconds in this embodiment) is reset. Then, in step S5, the low pressure Te is set to a recovery judgment value Te2 [-0
, 5-(FT-30)
2 and reset timer 1.

On the other hand, while the low pressure Te has not recovered to a level higher than the recovery determination value Te2, the timer 1 times out (30 seconds) in step S6.
ec elapsed), timer 2 (set to 5 min in this embodiment) is reset in step S1, and all indoor units 1-(A), . . . are activated to prevent freezing in step S8. Perform forced thermo-off operation.

That is, each indoor electric expansion valve (6), ... is closed, the indoor fan (not shown) is stopped, and each indoor heat exchanger (
Indoor heat exchanger (7) by reducing the amount of heat exchange in 7)
By increasing the temperature of the indoor heat exchangers (7),..., freezing of each indoor heat exchanger (7),... is prevented.

Then, in step S9, after 5 m1n has elapsed since the timer 2 was reset, the forced indoor thermo-off operation is performed until the timer 2 times up, and when the time expires, the process returns to step S2 and the normal indoor thermo-on permission is activated again. It is designed to perform cold storage heat and cooling operations at the same time.

] 7 On the other hand, during normal cooling operation, each indoor unit (A) to (
In C), illegal driving is performed in accordance with the procedure shown in the flowchart of FIG.

That is, in step Sll-S19, 7 of each indoor heat exchanger (7) detected by the limb sensor (ThN)
When the night tube temperature T is set to a predetermined evaporation temperature set value TLI (for example -
The same control as steps S1 to S9 in Figure 3 above is performed depending on whether the temperature is lower than the temperature (value of 7°C) or whether TMI continues for a predetermined period of time. However, TL! is the recovery determination value corresponding to Tc2 above. Here, the saturation temperature set value Tel is, for example, when the operating capacity of the compressor (1) is 13
0 (Hz), the value is about -6°C. on the other hand,
As mentioned above, the evaporation temperature set value TLl is a value of about -7°C, and when compared in terms of liquid refrigerant temperature, the evaporation temperature set value TLl is about -17°C.
is set to a value considerably lower than the saturation temperature set value Tel.

In the above flow, in step S8, during the same 9 evaporation operation in each evaporator, the evaporation pressure 8 force equivalent saturation temperature Te is set to a predetermined saturation temperature setting value according to the output of the pressure sensor (saturation temperature detection means) (Sp). When a state lower than Tel continues for a predetermined period of time, a simultaneous operation control means (51) is configured to perform anti-freezing operation in the user-side heat exchanger (evaporator) (7) for a predetermined period of time, and step With SI8, during normal cooling operation of the regenerative air conditioner, the liquid pipe sensor (evaporation temperature detection means) (Thl)
,... according to the output of each user-side heat exchanger (7),...
When the tube temperature (evaporation temperature) TL becomes lower than a predetermined evaporation temperature setting value (lower limit value) T1 at 1fJi, the normal cooling control means operates the freezing protection 1 in the user-side heat exchanger (7). (52) is configured.

Therefore, in the invention of claim (1), each indoor unit)
During the simultaneous cooling operation in (A) to (C), the saturation temperature Te corresponding to the evaporation pressure of the refrigerant in the suction line of the main refrigerant pipe (9) detected by the pressure sensor (average evaporation temperature detection means) (Sp) reaches a predetermined value. When the state of being lower than the saturation temperature set value Tel continues for a predetermined period of time, the simultaneous operation control means (51) controls each indoor heat exchanger (evaporator) (7) for a certain period of time.
, . . . are controlled to perform freezing prevention operation.

Here, as before, each indoor heat exchanger (7).

・In the case where the evaporation temperature of the refrigerant is individually detected from the liquid pipe temperature, etc., and when the temperature reaches a set value that causes freezing, antifreeze operation is performed, each indoor heat exchanger (7)... - Since there are variations in the characteristics and indicated values of the thermistors placed in the device, there is a risk that these errors will accumulate and impair reliability. In contrast, in the present invention, the saturation temperature T corresponding to the evaporation pressure of the refrigerant in the suction line is determined using a highly accurate pressure sensor.
e is detected and all indoor heat exchangers (7) are installed according to its value.
Since we are regularly performing anti-freeze operation,
There is no accumulation of such errors, and therefore reliability can be improved.

In the invention of claim (2), in the invention of claim (1), at least one of the evaporators is a heat storage tank (11).
If the other evaporator is an indoor heat exchanger (user-side heat exchanger) (7), the indoor heat exchanger (7) performs cooling operation while storing heat. During simultaneous cold storage heat and cooling operation in which refrigerant is evaporated in the coil (12) and cold heat is stored in the heat storage m (11) for ice making, etc., the operation control means (51)
When the evaporation pressure equivalent saturation temperature Te detected by the pressure sensor (Sp) is lower than a predetermined set value Tel, the indoor heat exchanger (7) is controlled to perform antifreeze operation.

Therefore, the indoor heat exchanger (7) and storage in such a heat storage type air conditioner,! Even when a plurality of evaporators having extremely different capacities and usage conditions are connected in parallel like the coil (11), the effect of the invention of claim (1) above can be exhibited.

In the invention of claim (3), in the invention of claim (2), as shown in FIG. When the wave tube temperature T detected by the nighttime sensor (Th fl) of the exchanger (7), ... is lower than the predetermined evaporation temperature set value TLI (for example, a value of about -7°C) Predetermined time TMI
When continuing, antifreeze operation (thaw operation) is performed in the indoor heat exchanger (7) (for example, antifreeze operation 1 (forced thermo-off) is entered at a temperature of about -]0°C).

Here, when such a heat storage type air conditioner is operating at the same time as storing cold heat and cooling, as shown in Fig. 6, even if the indoor heat exchanger (7) side freezes, the night temperature TL remains the same as in normal cooling operation. Without reaching the start determination temperature TLI of antifreeze operation in
°Cfn degree). Therefore, unlike conventional methods, the evaporation temperature is detected based on the liquid pipe temperature of the indoor heat exchanger (7), and the time to start the antifreeze operation is determined based only on the refrigerant condition on the indoor heat exchanger (7) side. Then, the judgment temperature Tll
to a high value (for example, a value about 1 to 2 degrees Celsius higher than -1 degrees Celsius)
I have no choice but to set it to . Then, during normal cooling operation, as shown in Figure 7, an anti-freezing operation command will be output even though there is no need to perform anti-freezing operation, and frequent cooling operations (for example, for 15 to 16 minutes), By repeating the hour IL operation (for example, for 10 minutes), it is inevitable that the feeling of empty lap will worsen.

In contrast, in the present invention, during the simultaneous cold storage heat and cooling operation, the saturation temperature Tc corresponding to the evaporation pressure is detected outside the room, and whether or not this value remains lower than the saturation temperature set value Tel for a predetermined period of time is determined. While the anti-freezing operation is carried out by standing up, the anti-freezing operation is not carried out in cold storage M during normal cooling operation and at the saturation temperature equivalent to the evaporation pressure during simultaneous cooling operation, so the saturation temperature set value Tel is set as the evaporation temperature. The set value TL+ can be set higher than the set value TL+. Therefore, during simultaneous cold storage heat and cooling operation, anti-freezing operation is performed in the indoor heat exchanger reliably, while anti-freezing operation is performed frequently during normal cooling operation. It is possible to effectively prevent the deterioration of the air-conditioned feeling due to

Note that the liquid pipe sensor (Thl
) Alternatively, a pressure sensor may be placed on the gas pipe side of each indoor heat exchanger (7).

The present invention can be applied not only to the regenerative air conditioner as in the above embodiment, but also to ordinary air conditioners. However, in case 3 of the regenerative air conditioner, even if the required capacity on the indoor heat exchanger (7) side decreases, the excess capacity is used on the ice making side, so the liquid pipe temperature does not drop below a certain level. Therefore, it is particularly effective in heat storage type air conditioners.

(Effects of the Invention) As explained above, according to the invention of claim (1), in a refrigeration system equipped with a plurality of evaporators, during simultaneous evaporation operation of each evaporator, the saturation temperature corresponding to the evaporation pressure on the suction side detect,
When the value becomes lower than the predetermined saturation temperature setting value, antifreeze operation is performed in the evaporator.
Freeze prevention operation can be performed at regular timing without causing errors in determining the freeze start time due to differences in the capacity of each evaporator or usage conditions.

According to the invention of claim (2), in the invention of claim (1), the refrigeration system is a regenerative air conditioner, and at least one of the plurality of evaporators is a regenerative coil and the other evaporator is a regenerative air conditioner. is a user-side heat exchanger, when cold storage heat and air conditioning are operated simultaneously, antifreeze operation is performed in the user-side heat exchanger when the saturation temperature equivalent to evaporation pressure is 4 degrees or lower than the specified saturation temperature setting value. Therefore, the influence of cold storage heat is J? J <, it is possible to accurately grasp the timing of judgment to prevent sermons, and therefore, the effect of the invention of claim (1) can be more significantly obtained.

According to the invention of claim (3), in addition to the invention of claim (2), during normal cooling operation, the evaporation temperature in each evaporator remains lower than the predetermined evaporation temperature setting value for a predetermined period of time. Since the freezing state is determined and the saturation temperature set value is set a predetermined temperature higher than the evaporation temperature set value, normal cooling operation can be performed while reliably preventing freezing during cold storage heat and cooling operation. In some cases, it is possible to prevent unnecessarily frequent antifreeze operation.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of the present invention. Figures 2 to 4 show embodiments of the present invention, Figure 2 is a refrigerant piping system diagram showing the overall configuration of the air conditioner, and Figure 3 is a flowchart diagram showing control details in the outdoor unit. , FIG. 4 is a flowchart showing control details in the indoor unit, and FIG. 5 is a characteristic diagram showing changes in liquid pipe temperature during normal cooling operation. 6 and 7 show the problems of the prior art, and FIG. 6 is a characteristic diagram showing changes in liquid pipe temperature during simultaneous operation of cold storage heat and cooling;
FIG. 7 is a characteristic diagram showing changes in liquid pipe temperature when anti-freezing operation is performed depending on the liquid pipe temperature. 1 Compressor 3 Outdoor heat exchanger (condenser) 6 Indoor electric expansion valve (pressure reduction mechanism) 7 Indoor heat exchanger (user side heat exchanger) 9 Main refrigerant piping 10 Main refrigerant circuit 11 Heat storage cypress 12 Storage H1 coil 13 minutes 1 branch pipe 6 21 branch pipe 5] Simultaneous operation control means 52 Normal cooling control means Sp Pressure sensor (saturation temperature detection means) Th, Q Liquid pipe sensor (evaporation temperature detection means) 7 "" --

Claims (3)

[Claims] (1) A pressure reducing mechanism (6 or 14) and an evaporator (7 or 12) are each connected in series to the main refrigerant pipe (9) connecting the compressor (1) and condenser (3). In a refrigeration system equipped with a refrigerant circuit (10) formed by connecting a plurality of branch pipes in parallel to form a closed circuit, the refrigerant circuit (10) is arranged on the suction side of the main refrigerant pipe (9) and has a saturation temperature corresponding to the evaporation pressure of the refrigerant. Saturation temperature detection means (Sp) to detect
During the simultaneous evaporation operation of each of the evaporators (7 or 12), etc., the saturation temperature corresponding to the evaporation pressure of the refrigerant is lower than the predetermined saturation temperature setting value based on the output of the saturation temperature detection means (Sp). An operation control device for a refrigeration system, comprising: simultaneous operation control means (51) for controlling the evaporator (7) to perform antifreeze operation for a predetermined period of time when a low state continues for a predetermined period of time. (2) The refrigeration system is a regenerative air conditioner equipped with a heat storage tank (11) that stores a heat storage medium capable of storing cold heat through heat exchange with a refrigerant, and at least one of the evaporators is connected to the heat storage medium. The heat storage coil (12) stores cold heat in the heat storage tank through heat exchange, and the other evaporator is the user side heat exchanger (7).
At the same time, the simultaneous operation control means (51) controls the utilization side heat exchanger (7
2. The operation control device for a refrigeration system according to claim 1, wherein the operation control device controls the freezing prevention operation in the step (1). (3) An evaporation temperature detection means (Thl) that individually detects the evaporation temperature of the refrigerant in the user-side heat exchanger (7), and during normal cooling operation in which the refrigerant evaporates only in the user-side heat exchanger (7);
According to the output of the evaporation temperature detection means (Thl), when the evaporation temperature in each user-side heat exchanger (7) continues to be lower than the predetermined evaporation temperature setting value for a predetermined period of time, the user-side heat exchanger (7) ), and the saturation temperature set value is set higher than the evaporation temperature set value by a predetermined temperature. Operation control device for refrigeration equipment.