JPH055407Y2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) This invention is designed to support both reheating and preheating operations in the cooling cycle.
Both reheating and post-cooling operations in the heating cycle are possible.
This invention relates to a heating and cooling system that can stably maintain a constant temperature in the intermediate temperature range of 15 to 20°C throughout the year.

(Prior art) There is a heating and cooling system that can finely control the temperature and capacity of the blown air, as exemplified in Japanese Utility Model Application Publication No. 175964/1982, and is used in precision machinery workshops and trunk rooms for storing high-quality leather, fur, etc. It has been used to maintain constant temperature and humidity in such cases.

For example, high quality products at food processing plants, etc.
Due to the growing demand for maintaining high freshness, there is an increasing number of cases in which working and storage environments are maintained at a constant temperature and humidity of 15 to 20 degrees Celsius throughout the year.

The above-mentioned known example is an appropriate device for maintaining constant temperature and humidity in the intermediate temperature range of 15 to 20°C. An auxiliary coil is installed in parallel in the air flow path passing through the user-side coil of the shape, and one connection end of the coil is connected via a pressure reduction mechanism to the end that becomes the low-pressure input side during cooling of the user-side coil and the high-pressure outlet side during heating. At the same time, the other connection end is branched and connected to a gas pipe connecting the four-way switching valve and the heat source side coil, and further connected to a series circuit between the pressure reducing mechanism and the auxiliary coil. The refrigerant is provided with an on-off valve that allows or interrupts the flow of refrigerant.

(Problem to be solved by the invention) The device having the above configuration uses the auxiliary coil as a reheater during operation in the cooling cycle, and uses the auxiliary coil as an aftercooler during operation in the heating cycle. However, since the capacity of the user-side coil and the auxiliary coil is fixed, there are two levels of capacity for both cooling and heating: single operation of the user-side coil alone and combined operation using the auxiliary coil. Since it is a control system, there are limits to the possibility of fine-grained control.

Furthermore, during cooling operation, the indoor temperature is as low as 15 degrees Celsius, so frost tends to form on the coils on the user side during long-term operation. It is not easy to keep the temperature constant.

Furthermore, if the outside air temperature falls during cooling reheating operation, the high pressure in the refrigeration circuit may drop, making it impossible to ensure reheating capacity.

In this way, there are several problems in actual operation, and this invention was made to solve them. It is possible to add a cooling (after-cooling) operation to each mode, allowing for a total of six operation modes, enabling more detailed temperature control and capacity control, making it versatile despite its simple structure. The aim is to provide a high-performance constant temperature and humidity device that can be used for

(Means for Solving the Problems) As is clear from the embodiments of the attached drawings, the present invention includes a compressor 1, a heat source coil 2, a pressure reducer 3, a utilization coil 4, and a four-way switching valve 5. In a heating and cooling system having a refrigerant circuit in which the direction of refrigerant flow can be switched, an auxiliary coil 7 is arranged in parallel on the leeward side of the air flow path passing through the use side coil 4 of the air-to-air type, and the pressure reducer 3 and A first electrically operated valve 8 of a reversible flow type capable of reducing pressure and controlling the flow rate is interposed in the middle of the second liquid pipe 12 that connects to the use side coil 4, while one coil end of the auxiliary coil 7 is connected to the second liquid pipe 12. Via a reversible flow type second electric valve 9 that can control pressure reduction and flow rate,
The second liquid pipe 12 is branched and connected to the part between the pressure reducer 3 and the first electric valve 8, and the other end of the coil is connected to the heat source side coil 2 through the third liquid pipe 13.
A switching valve device is provided between the third liquid pipe 13 and the gas pipe 14 which is branched and connected to the first liquid pipe 11 that connects the coil 4 and the four-way switching valve 5. 10, the switching valve device 1
0, the user side coil 4 and the auxiliary coil 7 are switched between the four-way switching valve 5 and the first liquid pipe 11.
It is characterized by being able to be alternately connected to and connected to.

(Function) In the present invention, the four-way switching valve 5 is switched to the cooling cycle, the switching valve device 10 is connected to the switching port where the user side coil 4 is the low-pressure inflow side of the four-way switching valve 5, and the auxiliary coil 7 By performing a switching operation to branch and connect the liquid pipe 11 to the first liquid pipe 11, the user coil 4 functions as a cooling coil and the auxiliary coil 7 functions as a reheating coil, thereby reproducing cooling with a capacity corresponding to high cooling loads. Thermal operation is accomplished (see Figure 1).

On the other hand, by switching the switching valve device 10 so that the utilization side coil 4 is branched and connected to the first liquid pipe 11 and the auxiliary coil 7 is connected to the switching port of the four-way switching valve 5, the utilization side coil 4 functions as a preheating coil and the auxiliary coil 7 functions as a cooling coil, making it possible to perform cooling preheating operation or cooling defrosting operation with a capacity corresponding to a low cooling load (see Figure 2).

Next, the four-way switching valve 5 is switched to the heating cycle, the switching valve device 10 is connected to the switching port where the user side coil 4 is the high-pressure outflow side of the four-way switching valve 5, and the auxiliary coil 7 is connected to the first By switching the branch connection to the liquid pipe 11, the user-side coil 4 functions as a heating coil and the auxiliary coil 7 functions as an after-cooling coil, providing heating with a capacity corresponding to low heating loads. A post-cooling operation is also possible, and a cooling operation can be performed while defrosting the utilization side coil 4 (see FIG. 3).

Furthermore, by switching the switching valve device 10 so that the utilization side coil 4 is branched and connected to the first liquid pipe 11, and the auxiliary coil 7 is connected to the switching port of the four-way switching valve 5, The utilization side coil 4 functions as a cooling coil, and the auxiliary coil 7 functions as a reheating coil, allowing reheating operation that can ensure reheating capacity even at low outside temperatures (see FIG. 4).

In this way, four types of operation modes are possible by switching between the four-way switching valve 5 and the switching valve device 10, and the cooling coil and heating coil can be selected in both the cooling and heating operation modes with fine-grained control. Blow air temperature control and capacity control can be easily performed.

(Embodiments) Examples of the present invention will be described below with reference to the attached drawings.

1 to 4 are device circuit diagrams showing examples of the device of the present invention according to operation mode, including a compressor 1, a heat source side coil 2, a pressure reducer 3, for example a capillary reach tube, and an air-type user side coil 4. , a four-way switching valve 5, and an accumulator 6 constitute a known reversible heat pump type refrigeration circuit, in which the heat source side coil 2 acts as a condenser and the user side coil 4 acts as an evaporator in the cooling cycle, and vice versa in the heating cycle. evaporator,
Acts as a condenser.

An auxiliary coil 7, a first electric valve 8, a second electric valve 9, and a switching valve device 10 are attached to the refrigeration circuit, and the auxiliary coil 7 is the user-side coil 4.
On the other hand, the coils are arranged side by side on the leeward side of the air flow path and have different heat transfer areas, for example, a coil with a smaller heat transfer area than the utilization side coil 4 is used.

The first motor-operated valve 8 and the second motor-operated valve 9 are reversible flow type valves that do not restrict the direction of fluid flow, and are capable of controlling pressure reduction and flow rate. The first motor-operated valve 8 is used as a pressure reducer 3. A second liquid pipe 12 connecting to the side coil 4
The second electric valve 9 has one connection port connected to the pressure reducer 3 in the second liquid pipe 12 and the first
A branch connection is made between the electric valve 8 and the other connection port is connected to one end of the auxiliary coil 7 in the refrigeration circuit.

The other coil end of the auxiliary coil 7 is branch-connected to a first liquid pipe 11 that connects the heat source side coil 2 and the pressure reducer 3 through a third liquid pipe 13 .

The switching valve device 10 uses, for example, a four-way switching valve, and this switching valve 10 is connected to a gas pipe 14 that connects the user-side coil 4 and the four-way switching valve 5, and the third liquid pipe 13. We are intervening in the middle.

The switching valve 10 has four ports and is capable of two-stage switching, with the first port connected to the gas pipe 1.
The second port is connected to the coil end of the auxiliary coil 7 by a part of the third liquid pipe 13, and the second port is connected to the coil end of the auxiliary coil 7 by a part of the third liquid pipe 13.
A portion of the gas pipe 14 and a portion of the third liquid pipe 13 are used to cool the four-way switching valve 5 through the third port and the fourth port, which are alternately switched and communicated with the first port and the second port. The first liquid pipe 11 is connected to a switching port which becomes a low pressure side during a cycle and a high pressure side during a heating cycle.

The structure of the refrigeration circuit is as explained above,
In each figure, 15 _A and 15 _B are temperature sensors attached to both ends of the coil 4 on the user side, and are for detecting the degree of superheating of the coil 4, and 16 _A and 16 _B are auxiliary coils. Temperature sensors 17 _A and 17 _B are attached to both coil ends of the heat source side coil 2 to detect the degree of superheat.

On the other hand, 18 indicates a humidity sensor that measures the humidity of the air after passing through the auxiliary coil 7 on the indoor side.

The openings of the first and second electric valves 8, 9 are controlled by the temperature and humidity signals detected by the sensors _15A to 18 as described below.

(A) Cooling reheat (cooling reheat) operation (see Figure 1), the four-way switching valve 5 is operated to the cooling cycle side, and the switching valve 10 is operated so that the first port and third port are switched to the second port and the fourth port is set to the cooling cycle side. When the ports are operated to communicate with each other, the refrigerant circulates in the direction of the arrow, and the user-side coil 4 functions as a cooling coil through which low-pressure refrigerant flows, and the auxiliary coil 7 functions as a reheating coil through which high-pressure refrigerant flows. After the air is cooled and dehumidified by the user-side coil 4, it is reheated by the auxiliary coil 7 and maintained at, for example, 15° C., and is sent into the room.

In _this case, the first electric valve ₈ On the other hand, the opening degree of the second electric valve 9 is controlled so that the humidity difference (ΔRH) between the humidity detected by the humidity regulator 18 and the set humidity falls within the range of ±10%. This valve control mode is as shown in flow diagrams in FIGS. 5 and 6.

The first electric valve 8 is used to reduce the pressure and control the flow rate so that the degree of superheating of the coil 4 on the user side remains at a constant value, and the second electric valve 9 is used to reduce the pressure and control the flow rate to reduce the pressure. High-pressure refrigerant G _A flowing into the container 3 and high-pressure refrigerant G _B flowing into the auxiliary coil 7
The reheating capacity of the auxiliary coil 7 is increased or decreased by adjusting the flow rate ratio between the auxiliary coil 7 and the auxiliary coil 7.

In this way, an indoor environment of constant temperature and humidity can be created.

(B) Cooling preheating (cooling preheat) operation (see Figure 2), the four-way switching valve 5 remains on the cooling cycle side, and the switching valve 10 switches between the first port, the fourth port, and the second and third ports. When operated so that they are connected to each other, the refrigerant circulates in the direction of the arrow, and the usage side coil 4 is used as the preheating (pireheat) coil through which the high-pressure refrigerant flows after passing through the heat source side coil 2, and the auxiliary coil 7 is connected to the preheating coil through which the low-pressure refrigerant flows. Each cooling coil functions separately, so the indoor air is preheated by the user-side coil 4 and then cooled by the auxiliary coil 7 to a temperature of 15°C.
The air maintained at this level is sent into the room.

In this case, the second electric valve 9 is opened so that the superheat degree (ΔSH) of the auxiliary coil 7 detected by the temperature controllers 16 _A and 16 _B falls within the range of 4° C. to 6° C. according to the procedure shown in FIG. On the other hand, the first humidity difference (ΔRH) due to the humidity detected by the humidity sensor 18 is controlled within a range of ±10%.
The opening of the electric valve 8 is controlled as shown in FIG.

That is, the first electric valve 8 adjusts the flow rate ratio of each refrigerant G _A and G _B to increase or decrease the preheating capacity of the user side coil 4, and the second electric valve 9 controls the degree of superheating of the auxiliary coil 7. Operate.

By the way, since the indoor temperature of the air conditioning system according to the present invention is lower than 15°C, which is lower than that of a normal air conditioner, the user side coil 4 is used during long-term operation.
frost will adhere to the surface.

In that case, a defrosting operation of the utilization side coil 4 is naturally required, but the cooling defrosting operation becomes possible by switching from the cooling reheat operation to this cooling preheat operation.

(C) After-heating cooling (after-heating cool) operation (see Figure 3), the four-way switching valve 5 is operated to the heating cycle side, and the switching valve 10 is operated so that the first port and third port are switched to the second port and the second port is set to the When the four ports are operated to communicate with each other, the refrigerant flows in the direction of the arrow, and the user-side coil 4 functions as a heating coil through which high-pressure refrigerant flows, and the auxiliary coil 7 functions as a cooling (after-cooling) coil through which low-pressure refrigerant flows. Therefore, after the indoor air is heated by the use side coil 4, it is heated by the auxiliary coil 7.
The air is post-cooled and maintained at 15°C and then sent into the room.

In this case, the first electric valve 8 is opened so that the degree of superheat (ΔSH) of the heat source coil 2 detected by the temperature regulators 17 _A and 17 _B falls within the range of 4° C. to 6° C. as shown in FIG. control the degree, while
The opening degree of the second electric valve 9 is controlled as shown in FIG. 6 so that the humidity difference (ΔRH) due to the humidity detected by the humidity sensor 18 is within the range of ±10%.

That is, the first electric valve 8 controls the degree of superheating of the heat source coil 2, and the second electric valve 9 controls the degree of superheating of each refrigerant.
It operates to increase or decrease the cooling capacity of the auxiliary coil 7 by adjusting the flow rate ratio of G _A and G _B.

Similar to the cooling preheating operation, this operation is suitable for defrosting the user-side coil 4 during operation, and at the same time is suitable for improving temperature control accuracy.

(D) Heating reheat (heating reheat) operation (see Figure 4), the four-way switching valve 5 remains in the heating cycle, and the switching valve 10 switches between the first and fourth ports and the second port.
When the port RO and the third port C are operated so as to communicate with each other, the refrigerant circulates in the direction of the arrow, and the user side coil 4 becomes the cooling coil through which the low-pressure refrigerant flows.
Since the auxiliary coils 7 function as reheating coils through which high-pressure refrigerant flows, indoor air flows through the user-side coils 4.
After being cooled and dehumidified by the auxiliary coil 7, the air is reheated and maintained at 15°C and sent into the room.

In this case, the degree of superheating (ΔSH) of the heat source side coil 2 detected by the temperature controllers 17 _A and 17 _B is 4°C.
The opening degree of the second electric valve 9 is controlled so that the humidity remains within the range of 6°C to 6°C, while the humidity difference (ΔRH) between the humidity detected by the humidity sensor 18 and the set temperature is
The opening degree of the first motor-operated valve 8 is controlled so that the difference falls within the range of ±10%, and the manner of this valve control is shown as a flow diagram in FIGS. 5 and 6.

The first electric valve 8 performs pressure reduction and flow control to control the intermediate pressure refrigerant G _A that flows to the pressure reducer 3 and the intermediate pressure refrigerant G _B that flows through the first electric valve 8 to the user side coil 4. The cooling capacity of the utilization side coil 4 is increased or decreased by adjusting the flow rate ratio, and the second electric valve 9 performs pressure reduction and flow rate control to maintain the superheat degree of the heat source side coil 2 at a constant level. The purpose is to ensure that

This heating reheating operation is switched to when the reheating capacity of the auxiliary coil 7 cannot be secured due to a drop in the outside air temperature and a drop in high pressure during the cooling reheating operation. , the cooling capacity and reheating capacity are well balanced, and stable constant temperature and humidity operation can be maintained.

The operation has been explained for each operation mode above, but in either the cooling or heating operation mode, the user side (indoor side) coil 4 can be used for cooling and heating, and two electric valves 8 and 9 are used as control valves. Since it uses , the amount of reheating and after-cooling can be directly increased or decreased, allowing fine-grained control over a wide adjustment range.

(Effects of the invention) The present invention is capable of preheating in addition to reheating in the cooling operation mode, and is also capable of reheating in addition to aftercooling in the heating operation mode. Therefore, four types of operation modes can be arbitrarily selected according to outside air conditions and load conditions to perform more precise constant temperature and humidity operation.

Furthermore, defrosting of the user-side coil 4 can be performed while performing the cooling operation in the cooling preheat operation mode or the heating aftercool operation mode, which has the advantage of minimizing room temperature fluctuations.

In addition, by creating a difference in the size of the heat transfer area between the user-side coil 4 and the auxiliary coil 7, it is possible to fine-tune the ability to match the load conditions by combining with the four types of operation modes. Cooling and heating operations can be performed simply and easily.

[Brief explanation of drawings]

FIGS. 1 to 4 are device circuit diagrams showing each operation mode according to an example of the device of the present invention, and FIGS. 5 and 6 are flow diagrams explaining aspects of electric valve control according to the example of the device of the present invention. be. 1... Compressor, 2... Heat source side coil, 3... Pressure reducer, 4... User side coil, 5... Four-way switching valve,
7... Auxiliary coil, 8... First electric valve, 9... Second electric valve, 10... Switching valve device, 11... First liquid pipe, 12... Second liquid pipe, 13... Third liquid pipe, 14
...Gas pipe.

Claims (1)

[Scope of utility model registration request] In a heating and cooling system having a refrigerant circuit comprising a compressor 1, a heat source side coil 2, a pressure reducer 3, a user side coil 4, and a four-way switching valve 5 and capable of switching the refrigerant flow direction, the user side coil 4 of an air-to-air type is used. A second liquid pipe 1 that connects the pressure reducer 3 and the user-side coil 4 by installing an auxiliary coil 7 in parallel on the leeward side of the air flow path passing through the
A reversible flow type electric valve 8 that can control the pressure reduction and flow rate is interposed in the middle of the auxiliary coil 7. A branch connection is made to a portion of the second liquid pipe 12 between the pressure reducer 3 and the first electric valve 8 via the second electric valve 9, and the other end of the coil is connected to the second liquid pipe 12 through the third liquid pipe 13. Heat source side coil 2 and pressure reducer 3
A switching valve device 10 is interposed between the third liquid pipe 13 and a gas pipe 14 that is branched and connected to the first liquid pipe 11 that connects the coil 4 and the four-way switching valve 5. At least, by switching the switching valve device 10, the user coil 4 and the auxiliary coil 7 can be alternately connected to the four-way switching valve 5 and the first liquid pipe 11. A heating and cooling system featuring: