JP2011007488A - Refrigerating air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid the deterioration of reliability caused by the start of a compressor when starting and stopping an individual heat source machine, in a refrigerating air conditioner handling one load by a plurality of the heat source machines.SOLUTION: The refrigerating air conditioner includes scroll compressors 3a, 3b inverter-driven to compress a coolant, air heat exchangers 5a, 5b for exchanging heat between the coolant and air, a pressure reducing device for reducing the pressure of the coolant, and a plurality of the heat source machines 1a, 1b each of which has a load-side heat exchanger which supplies cold to a heat load by exchanging heat between a liquid medium and the coolant. The liquid medium is made to serially flow in the heat source machines.

Description

  The present invention relates to a refrigeration air conditioner, and more particularly to a refrigeration air conditioner that supplies cold and hot heat to a load side by heating and cooling a liquid medium such as water and brine.

  For large-capacity air conditioning loads such as air conditioning in large-scale buildings, it is common practice to produce cold / hot water in a heat source unit and supply the cold / hot water to each load side for air conditioning. In these apparatuses, when a vapor compression heat source machine is used, a screw compressor that easily constitutes a relatively large capacity compressor is often used.

When a heat source unit installed in a building or the like is replaced at the time of renewal, in order to make it easy to carry in the equipment, it is updated from a single large-capacity heat source unit to multiple small, small-capacity heat source units. Is required. There exists a thing shown by patent document 1 as a refrigeration air conditioner comprised from such a several heat source machine.
In this conventional example, a plurality of heat source units using a screw compressor are configured, and the number of operating heat source units is determined so that the operating efficiency is maximized.

Japanese Patent Laid-Open No. 9-145176 (page 1-4, FIG. 2)

  However, the conventional refrigeration and air-conditioning apparatus has the following problems. In the case of one heat source unit, unless the load is reduced so that the corresponding heat source unit is started and stopped, the heat source unit is operated continuously, whereas when it is composed of a plurality of heat source units, a certain amount of load is applied. Since the capacity control is performed by switching the number of heat source units when the number of heat source units decreases, the number of times of starting and stopping the heat source units increases. The compressor is also started and stopped in response to the start and stop of the heat source machine. At this time, there has been a problem that the operation reliability of the compressor is lowered because the liquid back into which the liquid refrigerant is sucked at the time of starting the compressor and the bearing load and vibration due to the sudden increase of the shaft torque at the time of starting are likely to occur.

  In view of the above-described problems, the present invention reduces the number of times the compressor is started and stopped in the refrigeration air-conditioning apparatus including a plurality of heat source units, and avoids a factor of lowering reliability when starting the compressor. An object is to obtain a reliable refrigeration air conditioner.

  A refrigerating and air-conditioning apparatus according to the present invention includes a scroll compressor that is driven by an inverter to compress refrigerant, an air heat exchanger that performs heat exchange between the refrigerant and air, and a pressure of the refrigerant that is connected to the air heat exchanger. A pressure reducing device for reducing the pressure, a load side heat exchanger connected to the pressure reducing circuit for supplying cold heat or heat to the heat load by exchanging heat between the liquid medium and the refrigerant, and cooling the heat load. When supplying, the discharge side of the scroll compressor and the air heat exchanger are connected, and the suction side of the scroll compressor and the load side heat exchanger are connected to supply heat to the heat load. At the time, the discharge side of the scroll compressor and the load side heat exchanger are connected, and a plurality of heat source machines including a four-way valve connected to the suction side of the scroll compressor and the air heat exchanger are provided, The liquid medium There is characterized in that the flow through the respective heat source apparatuses in series.

  A refrigerating and air-conditioning apparatus according to the present invention includes a scroll compressor that is driven by an inverter to compress refrigerant, an air heat exchanger that performs heat exchange between the refrigerant and air, and a pressure of the refrigerant that is connected to the air heat exchanger. A pressure reducing device for reducing the pressure, a load side heat exchanger connected to the pressure reducing circuit for supplying cold heat or heat to the heat load by exchanging heat between the liquid medium and the refrigerant, and cooling the heat load. When supplying, the discharge side of the scroll compressor and the air heat exchanger are connected, and the suction side of the scroll compressor and the load side heat exchanger are connected to supply heat to the heat load. At the time, the discharge side of the scroll compressor and the load side heat exchanger are connected, and a plurality of heat source machines including a four-way valve connected to the suction side of the scroll compressor and the air heat exchanger are provided, The liquid medium There for you to flow the respective heat source apparatuses in series, performing the capacity control of the heat source apparatus individually, improve the reliability of the refrigeration air conditioning system, and improvement of the load tracking ability can be realized.

1 is a circuit diagram of a refrigerating and air-conditioning apparatus showing Embodiment 1 of the present invention. It is a figure which shows the correlation of the pressure and enthalpy of the refrigerating air-conditioning apparatus concerning Embodiment 1 of this invention. It is a figure which shows the control action of the refrigerating air conditioner in the cooling operation concerning Embodiment 1 of this invention. It is a figure which shows the control action of the refrigerating air conditioner in the cooling operation concerning Embodiment 1 of this invention. It is a figure which shows the control operation of the heat-source equipment in the cooling operation concerning Embodiment 1 of this invention. It is a figure which shows the control action of the refrigerating air-conditioning apparatus in the heating operation concerning Embodiment 1 of this invention. It is a figure which shows the control action of the refrigerating air-conditioning apparatus in the heating operation concerning Embodiment 1 of this invention. It is a figure which shows the control operation of the heat source machine in the heating operation concerning Embodiment 1 of this invention. It is sectional drawing of the compression chamber of the scroll compressor concerning Embodiment 1 of this invention. It is a figure which shows the compression torque fluctuation | variation of each compressor concerning Embodiment 1 of this invention. It is a figure which shows the compression stroke of the screw compressor concerning Embodiment 1 of this invention. It is a circuit diagram of the refrigerating and air-conditioning apparatus which shows Embodiment 2 of this invention. It is a figure which shows the correlation of the pressure and enthalpy of the refrigerating air-conditioning apparatus concerning Embodiment 2 of this invention. It is a figure which shows the control operation of the heat-source equipment in the cooling operation concerning Embodiment 1 of this invention. It is a circuit diagram of the refrigerating and air-conditioning apparatus which shows Embodiment 3 of this invention. It is a circuit diagram of the refrigerating and air-conditioning apparatus which shows Embodiment 4 of this invention. It is sectional drawing of the compression chamber of the scroll compressor concerning Embodiment 4 of this invention.

Embodiment 1 FIG.
Embodiment 1 of the present invention is shown in FIG. FIG. 1 is a circuit diagram of a refrigerating and air-conditioning apparatus according to the present invention. The heat source units 1a and 1b have the same configuration equipped with the same refrigerant circuit, and are connected in series in the present embodiment. In the heat source units 1a and 1b, there are a compressor 3, a four-way valve 4, an air heat exchanger 5, a check valve 6, a supercooling heat exchanger 7, a main expansion valve 8 which is a decompression device, and a load side heat exchanger. A water heat exchanger 9 and a bypass expansion valve 10 are built in and connected in an annular shape as shown in the figure to constitute a refrigerant circuit. An indoor heat exchanger 11 is built in the indoor unit 2 arranged on the load side such as an indoor space.
The pump 12 conveys cold / hot water that is a liquid medium flowing between the heat source unit 1 and the indoor unit 2, and the water storage tank 13 stores the cold / hot water as a buffer.
The compressor 3 is a scroll compressor, and is a type in which the rotation speed is controlled by an inverter and the capacity is controlled. The air heat exchanger 5 is a plate fin heat exchanger, and exchanges heat with the air around the heat source unit 1 conveyed by a blower. The supercooling heat exchanger 7 is a refrigerant / refrigerant heat exchanger, and is composed of a plate heat exchanger. The main expansion valve 8 and the bypass expansion valve 10 are electronic expansion valves whose opening degree is variably controlled. The water heat exchanger 9 is a plate heat exchanger, and performs heat exchange between a liquid medium such as cold / hot water being conveyed and the refrigerant. For example, R410A is used as the refrigerant of the refrigeration air conditioner.
In the indoor unit 2, a liquid medium such as cold / hot water that is cooled and heated by the heat source unit 1 is conveyed by the pump 12, and heat is exchanged with the air around the indoor unit 2 by the indoor heat exchanger 11 in the indoor unit 2. Cooling and heating operation is performed by
In the cooling operation in which the refrigerant circuit is connected in a ring shape and chilled water is produced by the water heat exchanger 7, the compressor 3, the four-way valve 4, the air heat exchanger 5, the check valve 6a (6e), and the supercooling heat exchanger 7 One flow path, the main expansion valve 8, the check valve 6d (6h), the water heat exchanger 9, the four-way valve 4, and the compressor 3 are connected in an annular shape, and the refrigerant flows in this order. Further, a part of the refrigerant exiting the supercooling heat exchanger 7 is branched and injected into the compression chamber of the compressor 3 through the bypass expansion valve 10 and the other flow path of the supercooling heat exchanger 7.
In the heating operation in which hot water is generated by the water heat exchanger 7, the compressor 3, the four-way valve 4, the water heat exchanger 7, the check valve 6b (6f), one flow path of the supercooling heat exchanger 7, the main expansion valve 8, the check valve 6c (6g), the air heat exchanger 5, the four-way valve 4, and the compressor 3 are connected in an annular shape, and the refrigerant flows in this order. In the heating operation, a part of the refrigerant exiting the supercooling heat exchanger 7 is branched, and the compressor is passed through the bypass expansion valve 10 and the other flow path of the supercooling heat exchanger 7 as in the cooling operation. 3 compression chambers.
In this way, an economizer circuit is constituted by a circuit that is branched from the supercooling heat exchanger 7 in the cooling and heating operation and then injected into the compressor 3 through the bypass expansion valve 10 and the supercooling heat exchanger 7.
The liquid medium is conveyed by the pump 12 and connected to the pump 12, the indoor heat exchanger 11, the water heat exchanger 9 a of the heat source machine 1 a, the water heat exchanger 9 b of the heat source machine 1 b, the water storage tank 13, and the pump 12. The flow path is conveyed in this order.

In the heat source devices 1a and 1b, pressure sensors 14a and 14c are provided on the suction side of the compressor 3, and pressure sensors 14b and 14d are provided on the discharge side of the compressor 3, and measure the refrigerant pressure at the installation location. Further, the temperature sensors 15a and 15i are the suction side of the compressor 3, the temperature sensors 15b and 15j are the discharge side of the compressor 3, the temperature sensors 15c and 15k are the outlet side during the cooling operation of the air heat exchanger 5, and the temperature sensors 15d and 15l are In the cooling operation of the water heat exchanger 7, the temperature sensors 15e and 15m are the inlet side of the flow path of the supercooling heat exchanger 7 on the economizer circuit, and the temperature sensors 15f and 15n are the supercooling heat exchanger on the economizer circuit. It is provided on the outlet side of the seven flow paths, and measures the refrigerant temperature at each installation location. Further, temperature sensors 15g and 15o are provided at the inflow portion of the liquid medium such as water in the water heat exchanger 7, and temperature sensors 15h and 15p are provided at the outflow portion of the liquid medium such as water in the water heat exchanger 7. Measure the temperature of the liquid medium at the location.
The temperature sensor 15q is provided on the liquid medium inflow side to the indoor unit 2, and the temperature sensor 15r is provided on the liquid medium inflow side to the indoor unit 2, and measures the temperature of the liquid medium at the installation location.
The temperature sensor 15s and the temperature sensor 15t are provided for measuring the air temperature around the heat source unit 1. The temperature sensor 15u is provided for measuring the indoor air temperature around the indoor unit 2.
The measurement control device 16 operates / stops the compressor 3 based on the measurement / operation information of the heat source unit 1 and the indoor unit 2 such as the pressure sensor 14 and the temperature sensor 15 and the operation content instructed by the refrigeration / air-conditioning device user. Each actuator is controlled such as the rotational speed, the blower air flow rate of the air heat exchanger 5, the opening of the main expansion valve 8 and the bypass expansion valve 10, and the transport amount of the pump 12.

Next, the operation | movement operation | movement in this refrigeration air conditioner is demonstrated based on FIG. 1, FIG. FIG. 2 is a diagram showing the relationship between the pressure and enthalpy of the refrigerating and air-conditioning apparatus according to Embodiment 1 of the present invention, in which the horizontal axis represents enthalpy and the vertical axis represents pressure. Since the operation of the heat source machine is the same for both the heat source machines 1a and 1b, the operation of the heat source machine 1a will be described as a representative.
First, the operation of the refrigerant circuit in the cooling operation will be described. In the cooling operation, the flow path of the four-way valve 4a is set in the direction of the solid line in FIG. The high-temperature and high-pressure (Ph) gas refrigerant (point A in FIG. 2) discharged from the compressor 3a flows into the air heat exchanger 5a through the four-way valve 4a and dissipates heat in the air heat exchanger 5a serving as a condenser. It condenses and liquefies (Fig. 2, point B). The high-pressure liquid refrigerant exiting the air heat exchanger 5a passes through the check valve 6a, and is further cooled by the refrigerant flowing through the economizer circuit in the supercooling heat exchanger 7a (point C in FIG. 2). It flows into 8a. The refrigerant in the two-phase state decompressed to a low pressure (Pl) by the main expansion valve 8a (D in FIG. 2) absorbs heat while evaporating and gasifying in the water heat exchanger 9a that becomes the evaporator through the check valve 6d. Then, the liquid medium is cooled to produce cold water. The refrigerant exiting the water heat exchanger 9a is sucked into the compressor 3a through the four-way valve 4a (point E in FIG. 2). A part of the high-pressure liquid refrigerant exiting the supercooling heat exchanger 7a is bypassed to the economizer circuit, and is depressurized to the intermediate pressure (Pm) by the bypass expansion valve 10a (point F in FIG. 2). The refrigerant flows into the other flow path of the exchanger 7a, exchanges heat with the high-pressure liquid refrigerant discharged from the air heat exchanger 5a, and is evaporated by heating (point G in FIG. 2). The refrigerant flowing through the economizer circuit is then injected into the compression chamber in the compressor 3a in the middle of compression and mixed with the refrigerant (point H in FIG. 2) from the suction state (point E in FIG. 2) (point I in FIG. 2). ), Compressed to a high pressure (Ph), and becomes a high-temperature and high-pressure gas refrigerant (point A in FIG. 2).
Next, the operation of the liquid medium in the cooling operation will be described. Cold water in the water storage tank 13, for example, cold water of 7 ° C. is sucked and conveyed by the liquid pump 12, flows into the indoor heat exchanger 11 in the indoor unit 2, and rises in temperature while cooling the ambient air, for example, 12 ° C. It flows out the indoor heat exchanger 11 and the indoor unit 2. Thereafter, the cold water that has flowed into the heat source unit 1a is cooled by the refrigerant in the water heat exchanger 9a and decreases in temperature, for example, becomes 9.5 ° C., and flows out of the water heat exchanger 9a and the heat source unit 1a. Thereafter, the cold water flows into the heat source unit 1b, is further cooled by the refrigerant in the water heat exchanger 9b and decreases in temperature, for example, reaches 7 ° C., flows out of the water heat exchanger 9b and the heat source unit 1b, and flows into the water storage tank 13 To do. The operation and operation of each component of the heat source unit 1b are the same as those of the heat source unit 1a.

Next, the operation of the refrigerant circuit in the heating operation will be described. Since the operations of the heat source units 1a and 1b are the same in the heating operation, the operation of the heat source unit 1a will be described as a representative. In the heating operation, the flow path of the four-way valve 4a is set in the direction of the dotted line in FIG. The state change of the refrigerant in the heating operation is almost the same as that in the cooling operation, and the state change shown in FIG. The high-temperature and high-pressure (Ph) gas refrigerant (point A in FIG. 2) discharged from the compressor 3a flows into the hydrothermal exchanger 9a via the four-way valve 4a, and dissipates heat in the hydrothermal exchanger 9a serving as a condenser. It condenses and liquefies (Fig. 2, point B). At this time, water as a liquid medium is heated to generate hot water. The high-pressure liquid refrigerant exiting the water heat exchanger 9a passes through the check valve 6b, and is further cooled by the refrigerant flowing through the economizer circuit in the supercooling heat exchanger 7a (point C in FIG. 2). It flows into 8a. The refrigerant is reduced to a low pressure (Pl) by the main expansion valve 8a to be a two-phase refrigerant (point D in FIG. 2), flows into the air heat exchanger 5a serving as an evaporator through the check valve 6c, and then flows into the air heat exchanger 5a. The gas is evaporated and is sucked into the compressor 3a through the four-way valve 4a (point E in FIG. 2). A part of the high-pressure liquid refrigerant exiting the supercooling heat exchanger 7a is bypassed to the economizer circuit, and after being depressurized to an intermediate pressure (Pm) by the bypass expansion valve 10a, the other side of the supercooling heat exchanger 7a. The heat is exchanged with the high-pressure liquid refrigerant exiting the water heat exchanger 9a and evaporated by heating (point G in FIG. 2). The refrigerant flowing through the economizer circuit is then injected into the compression chamber in the compressor 3a in the middle of compression and mixed with the refrigerant (point H in FIG. 2) from the suction state (point E in FIG. 2) (point I in FIG. 2). ), Compressed to a high pressure (Ph), and becomes a high-temperature and high-pressure gas refrigerant (point A in FIG. 2).
Next, the operation of the liquid medium in the heating operation will be described. High temperature in the water storage tank 13, for example, 45 ° C. hot water is sucked and conveyed by the liquid pump 12, flows into the indoor heat exchanger 11 in the indoor unit 2, and decreases in temperature while heating the ambient air, for example, 40 ° C. It flows out the indoor heat exchanger 11 and the indoor unit 2. Thereafter, the hot water flowing into the heat source unit 1a is heated by the refrigerant in the water heat exchanger 9a and rises in temperature, for example, reaches 42.5 ° C., and flows out of the water heat exchanger 9a and the heat source unit 1a. Thereafter, the hot water flows into the heat source unit 1b, further heated by the refrigerant to the water heat exchanger 9b and rises in temperature, for example, 45 ° C., flows out of the water heat exchanger 9b and the heat source unit 1b, and flows into the water storage tank 13 To do.

  In the cooling and heating operation, the water temperature supplied to the indoor unit 2 can be stabilized by holding a large amount of water in the water storage tank 13. The cooling / heating capacity of the heat source units 1a and 1b varies depending on the inflowing hot / cold water temperature, the outside air conditions, and the operation control of the heat source unit 1, and thus the cold / hot water temperature flowing out of the heat source unit 1 also varies. . If this cold / warm water is supplied to the indoor unit 2 as it is, the cooling / heating capacity of the indoor unit will also fluctuate, causing problems such as discomfort to the user when performing air conditioning, and for cooling purposes, etc. When it is desired to control the air state, the state becomes unstable, and a problem occurs if the predetermined state cannot be realized. If a large amount of water is retained in the water storage tank 13, even if the capacity fluctuation of the heat source device 1 occurs, the temperature fluctuation of the water storage tank 13 is small, and therefore the temperature fluctuation of the water supplied to the indoor unit 2 is also suppressed. The Therefore, the above-mentioned problem can be solved, and more comfortable air conditioning and stable air condition can be controlled.

Next, the control operation in this refrigeration air conditioner will be described. First, the cooling operation will be described with reference to FIGS. 3.1 and 3.2. First, the user of the refrigeration air conditioner sets a target value of the air conditioning temperature in the indoor unit 2 (ST101). When the target value and the indoor air temperature measured by the temperature sensor 15u are higher than the target value by a predetermined value, for example, 1 ° C., the operation of the refrigeration air conditioner is started (ST102). With the start of operation of the refrigeration air conditioner, the pump 12 starts with a predetermined initial capacity (ST103), and the operation of the heat source units 1a and 1b is instructed (ST104).
And after driving | running in this state, it controls according to an apparatus operating state.

In the initial state, both the heat source units 1a and 1b are operated. In the heat source apparatus 1 as a whole, the target is to cool the cold water temperature to a predetermined temperature, for example, 7 ° C. (ST105). The capacity control (water supply amount control) of the pump 12 is controlled so that the temperature of the cold water flowing out of the indoor unit 2 detected by the temperature sensor 15r becomes a preset target value, for example, 12 ° C. (ST106). When the capacity of the pump 12 is high, the flow rate of the cold water increases, so that the change in the water temperature becomes small, and the water temperature at the outlet of the indoor heat exchanger 11 becomes difficult to rise and falls. On the other hand, when the capacity of the pump 12 is low, the flow rate of the cold water decreases, so the change in the water temperature increases and the water temperature at the outlet of the indoor heat exchanger 11 rises. Therefore, the water temperature at the outlet of the indoor heat exchanger 11 is compared with the target value. When the water temperature is high, the capacity of the pump 12 is increased, and when the water temperature is low, the capacity of the pump 12 is decreased (ST107).
When the two heat source units 1a and 1b are operated, the two units are cooled to a predetermined cold water temperature, and the water temperature flowing into the heat source unit 1 is controlled to 12 ° C. by controlling the capacity of the pump 12, for example. In this case, the cooling target temperature of the cold water in the heat source unit 1 is set so that the heat source unit 1a is cooled to 9.5 ° C. and the heat source unit 1b is cooled to 7 ° C., and the capacity of the compressor 3 is controlled accordingly. The When one heat source unit 1 is operated, the chilled water cooling target temperature is set so that the operating heat source unit 1 realizes the target cooling temperature of the entire heat source unit 1, and the compressor 3 The capacity is controlled. A capacity control method of the compressor 3 will be described later.

The number of operating heat source units 1 is controlled according to the capacity of the compressor 3 of the heat source units 1a and 1b (ST108 in FIG. 3.2). When both the heat source units 1a and 1b are operated and the compressor capacity control is performed as described above, if the total capacity of the compressors 3 of the heat source units 1a and 1b is less than a predetermined value, for example, the total capacity is When the maximum capacity is 30% or less (ST109), it is determined that the cooling capacity of the heat source unit 1 is excessive with respect to the cooling load even if the two heat source units are operating, and the heat source unit 1 is operated. The number of units is decreased, and the operation of either one of the heat source units 1a and 1b is stopped (ST110).
Conversely, when the number of operating heat source units 1 is one and the capacity of the compressor 3 of the operating heat source unit 1 exceeds a predetermined value, for example, 90% or more of the maximum capacity of the heat source unit 1 If it becomes (ST111), in the operation of one heat source unit, it is determined that the cooling capacity of the heat source unit 1 is insufficient with respect to the cooling load, and the number of operating heat source units 1 is increased and stopped. The operation of the machine 1 is started (ST112).

Further, the number of operating heat source units is also controlled by the temperature of water sent from the water storage tank 13 to the indoor unit 2. The temperature of the water fed from the water storage tank 13 to the indoor unit 2 is detected by the temperature sensor 15q, and it is determined whether this temperature is the target temperature (ST113). If the water temperature is higher than the predetermined value, for example, the target water temperature Is 8 ° C, which is 1 ° C higher than 7 ° C, it is determined that the cooling capacity of the heat source device 1 is insufficient with respect to the cooling load, the number of operating heat source devices 1 is increased, and the heat source is stopped. The operation of the machine 1 is started. On the contrary, when the temperature of the water sent from the water storage tank 13 to the indoor unit 2 is lower than a predetermined value, for example, when the target water temperature is 7 ° C. and 6 ° C. lower by 1 ° C., the heat source device 1 is cooled. It is determined that the capacity is excessive with respect to the cooling load, and the number of operating heat source units 1 is decreased (ST114). At this time, when both of the heat source devices 1 are operating, one unit is operated. However, when only one unit is operating, all the operations of the heat source units 1 are stopped.
Also, when the indoor air temperature detected by the temperature sensor 15u is lower than a target value by a predetermined value, for example, 2 ° C. (ST115), it is determined that the cooling capacity of the heat source unit 1 is excessive with respect to the cooling load, and the heat source unit 1 Control is performed to reduce the number of operating units or to stop all the heat source units and stop the water supply of the pump 12 (ST116). Thereafter, the process returns to step ST105 to confirm the temperature setting, and the above-described steps ST105 to ST116 are repeated (from A in FIG. 3.1 to A in FIG. 3.2).

Next, the control operation in the heat source unit 1 during the cooling operation will be described with reference to FIG. Also in the control operation, the same operation is performed for the heat source devices 1a and 1b. Therefore, the operation control of the heat source device 1a will be described as a representative.
First, when the heat source unit 1a is activated (ST201), the rotation speed of the compressor 3a, the amount of air blown to the air heat exchanger 5a, the opening of the main expansion valve 8a, and the opening of the bypass expansion valve 10a are set to initial values. Operation is performed (ST202). The initial setting value of the air flow rate of the air heat exchanger 5a is determined by comparing the outside air temperature detected by the temperature sensor 15s and a predetermined value stored in the measurement control device 16 in advance. Here, the predetermined value to be compared with the outside air temperature is determined based on equipment performance such as the operating capacity of the compressor and heat exchanger performance, so that the high pressure of the refrigeration cycle (pressure of the refrigerant discharged from the compressor 3a) does not decrease too much. Therefore, the high air volume is set when the outside air temperature is high, and the low air volume is set when it is low.

  And after driving | running in this state, each actuator is controlled according to an apparatus operating state. First, the rotation speed of the compressor 3 is controlled so that the cold water temperature at the outlet of the hydrothermal exchanger 9 detected by the temperature sensor 15h becomes a preset target value (ST203). As described above, the target temperature differs between the heat source devices 1a and 1b. For example, the target temperature is set to 9.5 ° C. for the heat source device 1a and 7 ° C. for the heat source device 1b. If the rotation speed of the compressor 3 is high, the refrigerant flow rate increases, the cooling capacity of the apparatus increases, and the water is further cooled, so the water temperature at the outlet of the water heat exchanger 9 decreases. Conversely, when the rotation speed of the compressor 3 is low, the water temperature at the outlet of the water heat exchanger 9 rises. Therefore, the water temperature at the outlet of the water heat exchanger 9 is compared with the target value. When the water temperature is high, the rotational speed of the compressor 3 is increased, and when the water temperature is low, the rotational speed of the compressor 3 is decreased (ST204).

  Next, although it is the air flow rate of the air heat exchanger 5, this air flow rate is basically operated at an initial set value. However, if the high pressure detected by the pressure sensor 14b deviates from the predetermined range depending on the operating conditions, check whether the high pressure is within the predetermined range (ST205), and if the high pressure has increased excessively In order to protect the compressor 3a, control is performed to increase the air volume. If the high pressure is excessively reduced, the low pressure (pressure of the refrigerant sucked by the compressor 3a) is greatly reduced even if the opening degree of the main expansion valve 8 is controlled, the refrigerant evaporation temperature is lowered below the freezing point, Since there is a risk of freezing, control is performed to reduce the air volume so as to suppress an excessive decrease in high pressure (ST206).

Next, the opening degree of the main expansion valve 8a, which is the outlet of the water heat exchanger 9a serving as an evaporator, calculates the refrigerant superheat degree SH in the state of suction of the compressor 3a (point E in FIG. 2) (ST208). ), The refrigerant superheat degree SH is controlled to be a preset target value, for example, 2 ° C. (ST209). Here, the refrigerant superheat degree SH at the outlet of the water heat exchanger 9a and sucked into the compressor 3a is (temperature sensor 15a detected temperature (intake temperature of the compressor 3)) − (refrigerant saturation temperature converted from the pressure sensor 14a). Use the value calculated in.
When the opening of the main expansion valve 8a decreases, the flow rate of the refrigerant flowing through the water heat exchanger 9a decreases, the refrigerant superheat degree SH at the outlet of the water heat exchanger 9a increases, and conversely, the opening of the main expansion valve 8a increases. Then, the refrigerant superheat degree SH of the water heat exchanger 9a becomes small. Therefore, the refrigerant superheat degree SH of the compressor 3a suction (water heat exchanger 9a outlet) is compared with the target value, and when the refrigerant superheat degree SH is larger than the target value, the opening degree of the main expansion valve 8a is largely controlled. When the refrigerant superheat degree SH is smaller than the target value, the opening degree of the main expansion valve 8a is controlled to be small (ST210).

Next, the opening degree of the bypass expansion valve 10a, the refrigerant superheat degree Sheco at the outlet of the supercooling heat exchanger 7a on the economizer circuit (point G in FIG. 2) is calculated (ST211), and the refrigerant superheat degree Sheco is Control is performed so that the target value is set in advance, for example, 2 ° C. (ST212). Here, the refrigerant superheat degree SHeco at the outlet of the supercooling heat exchanger 7 uses a value calculated from the temperature sensor 15f detected temperature-temperature sensor 15e detected temperature.
When the opening degree of the bypass expansion valve 10a is reduced, the flow rate of the refrigerant flowing through the economizer circuit is decreased, the refrigerant superheat degree SH at the outlet of the supercooling heat exchanger 7a on the economizer circuit is increased, and conversely, the opening degree of the bypass expansion valve 10a. Is increased, the refrigerant superheat degree SH at the outlet of the supercooling heat exchanger 7a is decreased. Therefore, the refrigerant superheat degree Sheco at the outlet of the supercooling heat exchanger 7a is compared with the target value, and when the refrigerant superheat degree SHeco is larger than the target value, the opening degree of the bypass expansion valve 10a is controlled to be large, and the refrigerant superheat degree is determined. When the Sheco is smaller than the target value, the opening degree of the bypass expansion valve 10a is controlled to be small (ST213).
Then, it returns to step ST203 again, it is detected whether the outlet water temperature of the water heat exchanger 9 has become target value, and the process of step ST204-ST213 is repeated according to a detection result.

Next, a control method of the refrigeration air conditioner in the heating operation will be described with reference to FIG. First, the user of the refrigeration air conditioner sets a target value of the air conditioning temperature in the indoor unit 2 (ST301). When the target value and the indoor air temperature measured by the temperature sensor 15u are lower than the target value by a predetermined value, for example, 1 ° C., the operation of the refrigeration air conditioner is started (ST302). With the start of operation of the refrigeration air conditioner, the pump 12 starts with a predetermined initial capacity (ST303), and the operation of the heat source units 1a and 1b is instructed (ST304). In the initial state, both the heat source units 1a and 1b are operated.
And after driving | running in this state, it controls according to an apparatus operating state.

  The capacity control (water supply amount control) of the pump 12 is controlled such that the temperature of the hot water flowing out of the indoor unit 2 detected by the temperature sensor 15r becomes a preset target value, for example, 40 ° C. (ST305). When the capacity of the pump 12 is high, the hot water flow rate increases, so that the change in the water temperature becomes small, and the water temperature at the outlet of the indoor heat exchanger 11 becomes difficult to decrease and rises. On the other hand, when the capacity of the pump 12 is low, the flow rate of the hot water decreases, so that the change in the water temperature increases, and the water temperature at the outlet of the indoor heat exchanger 11 decreases. Therefore, the water temperature at the outlet of the indoor heat exchanger 11 is compared with the target value (ST306). When the water temperature is low, the capacity of the pump 12 is increased, and when the water temperature is high, the capacity of the pump 12 is decreased. In the heat source apparatus 1 as a whole, the target is to heat the hot water temperature to a predetermined temperature, for example, 45 ° C. (ST307).

When two heat source units 1 are operated, heating is performed up to a predetermined hot water temperature for two units. For example, when the water temperature flowing into the heat source unit 1 is controlled to 40 ° C. by the capacity control of the pump 12. The heating target temperature of the hot water in the heat source unit 1 is set so that the heat source unit 1a is heated to 42.5 ° C. and the heat source unit 1b is heated to 45 ° C., and the capacity of the compressor 3 is controlled. When one heat source unit 1 is operated, the hot water heating target temperature is set so that the operating heat source unit 1 realizes the target heating temperature of the entire heat source unit 1, and the compressor 3 The capacity is controlled (ST308 in FIG. 5.2). A capacity control method of the compressor 3 will be described later.

The number of operating heat source units 1 is controlled according to the capacity of the compressor 3 of the heat source units 1a and 1b. When both the heat source units 1a and 1b are operated and the compressor capacity control is performed as described above, if the total capacity of the compressors 3 of the heat source units 1a and 1b is less than a predetermined value, for example, the total capacity is When it becomes 30% or less of the maximum capacity (ST309), it is judged that the heating capacity of the heat source unit 1 is excessive with respect to the heating load even if it is operated with two heat source units. The number is reduced, and the operation of either one of the heat source units 1a and 1b is stopped (ST310).
Conversely, when the number of operating heat source units 1 is one and the capacity of the compressor 3 of the operating heat source unit 1 exceeds a predetermined value, for example, 90% or more of the maximum capacity of the heat source unit 1 If it becomes (ST311), in the operation of one heat source unit, it is determined that the heating capacity of the heat source unit 1 is insufficient with respect to the heating load, the number of operating heat source units 1 is increased, and the heat source is stopped. The operation of the machine 1 is started (ST312).

Further, the number of operating heat source units is also controlled by the temperature of water sent from the water storage tank 13 to the indoor unit 2. The water temperature sent from the water storage tank 13 to the indoor unit 2 is compared with the cold water cooling target temperature (ST313), and when the water temperature is lower than the target value, for example, the target water temperature is 45 ° C and 44 ° C lower by 1 ° C. In such a case, it is determined that the heating capacity of the heat source unit 1 is insufficient with respect to the heating load, the number of operating heat source units 1 is increased, and the operation of the stopped heat source unit 1 is started. On the contrary, when the temperature of the water sent from the water storage tank 13 to the indoor unit 2 is higher than a predetermined value, for example, when the target water temperature is 45 ° C. and becomes 1 ° C. higher than 46 ° C., the heat source device 1 is heated. The capacity is judged to be excessive with respect to the heating load, and the number of operating heat source units 1 is decreased. At this time, when both the heat source devices 1 are operating, one unit is operated. However, when only one unit is operating, the operation of the heat source devices 1 is completely stopped (ST314).
Further, when the indoor air temperature is higher than a target value by a predetermined value, for example, 2 ° C. or more (ST315), it is determined that the heating capacity of the heat source unit 1 is excessive with respect to the heating load, and the number of operating heat source units 1 is decreased. Control is performed to stop all the heat source devices and stop water supply of the pump 12 (ST316).
Then, it returns to step ST305 again, temperature setting is confirmed, and the cycle of said step ST305-ST316 is repeated.

Next, the control operation in the heat source unit 1 during the heating operation will be described with reference to FIG. Also in the control operation, the same operation is performed for the heat source units 1a and 1b, and therefore, the operation control of the heat source unit 1a will be described as a representative.
First, operation is performed by setting the number of rotations of the compressor 3a, the amount of air blown from the air heat exchanger 5a, the opening of the main expansion valve 8a, and the opening of the bypass expansion valve 10a to initial values (ST402). Here, the initial setting value of the air heat exchanger 5 is determined by comparing the outside air temperature detected by the temperature sensor 15s with a predetermined value stored in advance in the measurement control device 16, and is high when the outside air temperature is low. If the air volume is high, the air volume is set low.

  And after driving | running in this state, each actuator is controlled according to an apparatus operating state. First, the rotational speed of the compressor 3 is controlled so that the hot water temperature at the outlet of the hydrothermal exchanger 9 detected by the temperature sensor 15h becomes a preset target value (ST403). As described above, the target temperature differs between the heat source devices 1a and 1b. For example, the target temperature is set to 42.5 ° C. for the heat source device 1a and 45 ° C. for the heat source device 1b. If the rotation speed of the compressor 3 is high, the refrigerant flow rate increases, the cooling capacity of the apparatus increases, and the water is further heated, so the water temperature at the outlet of the water heat exchanger 9 rises. On the contrary, when the rotation speed of the compressor 3 is low, the water temperature at the outlet of the water heat exchanger 9 is lowered. Therefore, the water temperature at the outlet of the water heat exchanger 9 is compared with the target value. When the water temperature is low, the rotational speed of the compressor 3 is increased, and when the water temperature is high, the rotational speed of the compressor 3 is decreased (ST404).

  Next, although it is the air flow rate of the air heat exchanger 5, this air flow rate is basically operated at an initial set value. As a situation, when heating operation is performed at a high outside air temperature (for example, about 15 ° C.), the air volume is reduced to prevent the load on the compressor from becoming excessive, the low pressure of the refrigeration cycle is reduced, and the compressor Although the compressor drive load may be reduced by reducing the transport flow rate of the building, in the case of a building air conditioner or the like in which the refrigeration air conditioner targeted by the present invention is used, a heating load is generated at a high outside temperature. Since there is almost nothing, operation is performed at the initial set value as described above.

Next, the opening degree of the main expansion valve 8a, which is the outlet of the air heat exchanger 5a serving as an evaporator, and the refrigerant superheat degree SH in the state of suction of the compressor 3a (point E in FIG. 2) is set in advance. The target value is controlled to be, for example, 2 ° C. (ST406). Here, the refrigerant superheat degree SH at the outlet of the air heat exchanger 5a and sucked into the compressor 3a is (temperature sensor 15a detected temperature (intake temperature of the compressor 3)) − (refrigerant saturation temperature converted from the pressure sensor 14a). Use the value calculated in.
When the opening of the main expansion valve 8a decreases, the flow rate of the refrigerant flowing through the air heat exchanger 5a decreases, the refrigerant superheat degree SH at the outlet of the air heat exchanger 5a increases, and conversely, the opening of the main expansion valve 8a increases. Then, the refrigerant superheat degree SH of the air heat exchanger 5a becomes small. Therefore, the refrigerant superheat degree SH of the compressor 3a intake (air heat exchanger 5a outlet) is compared with the target value, and when the refrigerant superheat degree SH is larger than the target value, the opening degree of the main expansion valve 8a is largely controlled. When the refrigerant superheat degree SH is smaller than the target value, the opening degree of the main expansion valve 8a is controlled to be small (ST407).

  Next, the opening of the bypass expansion valve 10a is performed in the same manner as the cooling operation, and the refrigerant superheat degree Sheco at the outlet of the supercooling heat exchanger 7a is calculated (ST408), and the refrigerant superheat degree Sheco and the target value are calculated. In comparison (ST409), when the refrigerant superheat degree SHeco is larger than the target value, the opening degree of the bypass expansion valve 10a is controlled to be large, and when the refrigerant superheat degree SHeco is smaller than the target value, the opening degree of the bypass expansion valve 10a. Is controlled to be small (ST410).

  In the cooling speed / heating operation, the rotational speed control of the compressor 3, the opening of the main expansion valve 8 and the bypass expansion valve 10, and the capacity control of the pump 12, the PID control method based on the deviation from the target value, etc. Thus, the control amount is determined.

  Next, characteristics of the scroll compressor used as the compressor 3 of the heat source unit 1 will be described. FIG. 7 is a view showing a cross section of the compression chamber of the scroll compressor. In the scroll compressor, compression chambers 19a, 19b, and 19c are formed in the space between the orbiting scroll 17 and the fixed scroll 18, and the orbiting scroll 17 performs an orbiting motion, so that the compression chamber 19 rotates. At the same time, the compression chamber volume decreases and the refrigerant in the compression chamber is compressed. The refrigerant in the outermost compression chamber 19a is in a state where the suction into the compression chamber is completed and compression is started, and the swing scroll is moved to the position of the compression chamber 19b after one rotation and to the position of the compression chamber 19c after two rotations. It moves, completes compression, and is discharged from the discharge port 20 at the center of the scroll.

  As described above, in the scroll compressor, since the compression is completed after two or more rotations from the start of compression, fluctuations in the compression torque required in the compression process are reduced. FIG. 8 shows fluctuations in the compression torque of the reciprocating compressor, rotary compressor, and scroll compressor. It can be seen that the fluctuation in the compression torque of the scroll compressor is 1/10 or more smaller than other types. .

  Thus, the following effects can be acquired by applying a scroll compressor because compression torque is small. When applying a plurality of heat source units as in the present invention, especially when one unit is divided into a plurality of units so far, the number of times the heat source unit is started and stopped increases accordingly, and the heat source unit is started and stopped. In response, the compressor is also started and stopped. When the compressor is started, the fluctuation of the compression torque is large, and a large load is applied to the compressor bearing. When the scroll compressor is applied, since the fluctuation of the compression torque itself is small, the fluctuation of the compression torque at the start-up is small, the bearing load applied to the compressor bearing can be reduced, and the reliability during the operation of the compressor can be increased. Further, since the fluctuation of the compression torque is small, the vibration at the time of starting can be suppressed, and the reliability of the apparatus can be increased also in this respect.

Further, the conventional screw compressor has the following problems. FIG. 9 shows the compression stroke of the screw compressor. As shown in FIG. 9, in the screw compressor, the compression chamber 19 is formed in a space sandwiched between the screw portion 22 and the gate rotor portion 23. Since this shape is a three-dimensional shape, it is difficult to process, and a gap larger than the scroll compressor is generated in the compression chamber. In order to prevent the refrigerant being compressed from leaking from the gap generated in the compression chamber, a large amount of refrigerating machine oil is used in the screw compressor. Therefore, a large amount of refrigerating machine oil is also contained in the refrigerant in the compressor discharge section. When this refrigerating machine oil flows out into the circuit, the heat exchange of the refrigerant in the air heat exchanger 5 and the water heat exchanger 9 is hindered, so that there is a problem that the heat transfer efficiency is lowered and the operation efficiency of the apparatus is lowered. . In order to avoid this problem, an oil separator may be provided at the compressor discharge section. However, when one heat source unit is divided into a plurality of units and renewed, the oil separation is performed on all of the plurality of heat source units. There is a problem that the cost of the apparatus rises.
Further, when the capacity of the screw compressor is reduced, there is a problem that the ratio of the gap to the volume to be compressed is increased due to the problem of processing accuracy, and the efficiency is lowered. The capacity for which the efficiency is reduced is in the range of cooling capacity of about 100 to 150 kW, especially when trying to construct a model with a capacity of about 50 kW, which is a guide when carrying in with a building elevator or a small crane. There was a problem of becoming significant.

Since the scroll compressor has a two-dimensional shape, the processing accuracy can be higher than that of the screw compressor, and the amount of refrigeration oil contained in the discharged refrigerant can be reduced. This eliminates the need for an oil separator, and is advantageous in that the apparatus can be configured at low cost when one heat source unit is divided into a plurality of units and renewed.
Further, in a system in which a heat source unit and an indoor unit are connected by a refrigerant pipe in a direct expansion system, oil stagnating in the refrigerant pipe is generated, and the amount of the oil may increase and cause the exhaustion of refrigerating machine oil. Therefore, the installation of an oil separator is indispensable. However, in the case of a chiller that supplies a liquid medium such as cold / hot water to the load side as in the present invention, there is no stagnation of refrigerating machine oil in the above-mentioned piping. Therefore, it is not necessary to install an oil separator, and the apparatus can be configured at low cost.
Further, in the case of a scroll compressor, when a small-capacity model is to be constructed, since the gap of the compression chamber can be made relatively small, high efficiency can be maintained up to a capacity of about 3 kW. Therefore, even a heat source device configuration in which a heat source device having a capacity of about 100 kW or more, which is currently configured with one screw compressor, is divided into a plurality of units can be highly efficient.

In the case of a chiller that supplies liquid medium such as cold / hot water to the load side, the temperature of the liquid medium such as cold / hot water supplied to the load side is fixed. Operation) or high pressure (during heating operation) is fixed, and operation is performed at a relatively high compression ratio. A compressor with no internal volume ratio such as a reciprocating compressor and a rotary compressor, where the discharge part and the suction part are adjacent to each other, can be operated efficiently at a low compression ratio, but at a high compression ratio, refrigerant leakage in the compressor is large. Operating efficiency is greatly reduced. In the case of a scroll compressor, as shown in FIG. 7, since the compression chambers of the discharge part and the suction part are not adjacent to each other, high efficiency operation can be performed even at a high compression ratio.
In the case of a scroll compressor, there is an internal volume ratio, and operation at a lower compression ratio results in an overcompressed state and the operation efficiency is greatly reduced. In the case of a chiller, the refrigeration cycle has a low pressure (during cooling operation) or a high pressure. Since the operation is fixed (heating operation), the difference between the internal volume ratio and the compression ratio can be reduced by selecting an internal volume that matches the operating state. It can be operated with high efficiency.

In the present invention, the rotation speed of the compressor 3 is controlled by an inverter, and the following effects can be obtained. First, when a plurality of heat source devices 1 are used, the compressors of all the heat source devices are inverter-controlled, so that the capacity control width in each heat source device number is expanded. For example, if all compressors are operated at a constant speed with two heat source units of the same capacity, the capacity when operating with two heat source units is 200% (100% is the capacity per heat source unit) ) The capacity when operated with one heat source unit is 100%. In this case, since continuous capacity control cannot be performed, the start and stop of the heat source unit is inevitable at any capacity, the number of start and stop times of the compressor is increased, and the reliability is lowered.
Also, when one heat source unit is driven by an inverter and the capacity control width is 50% -150%, when one heat source unit is driven by a constant speed compressor, the capacity when operated by two heat source units is The capacity when operated with 150% -250% and one heat source machine is 50-150%. In this case, continuous capacity control can be performed. However, in the case of a load near 150%, only the heat source unit composed of a constant speed compressor will start and stop repeatedly, and the reliability of the compressor operation of the heat source unit Decreases.
When two heat source units are driven by an inverter and the capacity control width is 50% -150%, the capacity when operating with two heat source units is 100% -300% and operated with one heat source unit The capacity of the case is 50-150%. In this case, continuous capacity control can be performed and the capacity for switching the heat source machine can be in the vicinity of 100% and 150%. However, by appropriately selecting the number of operating heat source machines, continuous start and stop can be performed. Capacity control can be performed. Therefore, the number of start / stop times of the heat source device can be significantly reduced, and the reliability can be improved.

Further, by driving the inverter, the rotation speed when the compressor 3 is started can be controlled at a low speed. Thereby, the fluctuation | variation of the initial compression torque at the time of starting can be suppressed, a compressor bearing load can be reduced, and reliability can be improved.
Further, by controlling the rotation speed at the time of starting the compressor 3 to a low speed, the amount of liquid returning to the compressor 3 at the time of starting can be made small. In the chiller that supplies a liquid medium such as cold / hot water to the load side, when the air heat exchanger 5 is mounted, the volume difference between the water heat exchanger 9 and the air heat exchanger 5 is large, and the volume of the air heat exchanger 5 is It becomes 5 times or more of the water heat exchanger 9. When the cooling operation is performed with this configuration, a refrigerant amount of about 40% of the air heat exchanger 5 is required in order to obtain a degree of supercooling in the air heat exchanger 5 serving as a condenser. When the operation of the heat source unit 1 that was performing the cooling operation is stopped, the liquid refrigerant that has been present in the air heat exchanger 5 flows into the low-pressure side of the water heat exchanger 9 through the main expansion valve 8. To do. At this time, most of the refrigerant amount existing in the air heat exchanger 5 is in the form of liquid refrigerant, and its volume is more than twice that of the water heat exchanger 9, so the water heat exchanger 9 is liquid refrigerant. It will overflow. When starting operation is performed in this state, liquid back to the compressor 3 is unavoidable. When the liquid back occurs, the compression torque increases due to the liquid compression, and the oil in the compressor 3 is diluted with the liquid refrigerant, resulting in a decrease in the lubrication performance due to a decrease in the viscosity. descend.
In the direct expansion type and the like, there is a pipe connecting the heat source unit 1 and the indoor unit 2 as described above, so the liquid refrigerant overflowing from the air heat exchanger 5 is absorbed by the volume part of the pipe and the liquid back at start-up is alleviated. However, in the case of a chiller, since there is no other buffer part, the reliability is more likely to deteriorate due to liquid back.

Even under this condition, it is possible to control the rotation speed at the start of the compressor 3 at a low speed by driving the inverter, thereby suppressing an increase in the compression torque of the compressor 3 at the start of the start and a liquid flowing into the compressor 3. The absolute value of the amount of refrigerant can be reduced, and a decrease in viscosity due to oil dilution can also be suppressed. Therefore, highly reliable operation can be performed.
In order to avoid the liquid back, an accumulator can be provided for the suction of the compressor 3, but in this case, a single heat source device that can be handled by a single accumulator in the past is used for a plurality of heat source devices 1. Each of them requires an accumulator, which is not preferable because of high costs. In other words, an accumulator can be eliminated by driving the inverter, and the apparatus can be configured at low cost.

  When stopping the heat source machine 1 during operation, the main expansion valve 8 may be controlled to be closed during the stop. Thereby, the inflow of the liquid refrigerant from the air heat exchanger 5 while the heat source unit is stopped to the water heat exchanger 9 can be prevented, and the liquid back when the heat source unit 1 is started next time can be suppressed, thereby further improving the reliability. be able to.

  Further, when a plurality of heat source units are operated simultaneously, the temperature difference of the cold / hot water in the water heat exchanger 9 is set to be approximately the same in each heat source unit. Thereby, the capacity | capacitance of the compressor 3 of each heat source machine becomes comparable, and it can drive | operate on the refrigerant | coolant conditions of the same degree with the air heat exchanger 5 of each heat source machine 1, and the water heat exchanger 9 each heat exchanger. If a specific heat source unit 1 is biased and bears a load, the amount of heat exchange in the heat source unit 1 becomes excessive, and only the heat source unit has a high pressure, a low pressure, and an operation with reduced efficiency. The efficiency when viewed with the. High efficiency operation can be realized by ensuring that there is no heat source unit 1 that can uniformly exchange heat with each heat exchanger and whose efficiency is extremely reduced.

On the other hand, when the heat source device 1 is additionally operated, it is desirable to operate so that the capacity of the compressor 3 after the heat source device 1 is started is as small as possible. As described above, liquid back is likely to occur when the heat source unit 1 is started, and this situation continues for several minutes. Although it starts at a low speed at the time of startup, if the capacity of the compressor 3 is set to the same level as other heat source machines immediately after startup, a large amount of liquid back is generated depending on the operating conditions, and the operation reliability of the compressor 3 is increased. May decrease.
Therefore, the minimum capacity operation is continued so that the compressor capacity of the heat source machine 1 to be additionally operated is smaller than that of the other heat source machines for a few minutes after startup, or the cooling water cooling temperature The target setting of the hot water heating temperature is controlled to be lowered, and the capacity of the compressor 3 is reduced to ensure the operation reliability of the compressor 3.

At this time, by performing capacity control following the load fluctuation by compressor 3 capacity control by the inverter of the heat source device 1 other than the additional operation heat source device 1, it is possible to perform operation stably following the load. That is, by driving the compressor 3 of each heat source device with an inverter, it is possible to stably follow the load even under the condition that any heat source device 1 starts and stops.
Moreover, in the case of a chiller, it is set as the structure which suppresses the fluctuation | variation of the indoor unit water supply temperature when load followability by the on / off of the heat source machine 1 etc. falls by storing liquid media, such as excess water, in the water storage tank 13. However, as in the present invention, by reducing the on / off state of the heat source unit 1, the frequency of occurrence of on / off of the heat source unit 1 with the lowest load followability is reduced, and compression by the inverter in each heat source unit 1 Since the machine 3 capacity control can cope with load fluctuations including when the heat source machine 1 starts and stops, the water storage tank 13 can be made unnecessary, or its volume can be reduced, and the amount of water retained as a device can be reduced.
Therefore, the cost of the apparatus can be reduced, and the workability at the time of installation can be improved.

  Moreover, in this invention, the gas injection is performed to the compressor 3 via the economizer circuit. The refrigeration cycle when the gas injection is performed is as shown in FIG. 2, and some of the refrigerant compressed by the compressor 3 is compressed from the intermediate pressure Pm to the high pressure Ph. Therefore, while all the refrigerant is compressed from the low pressure Pl to the high pressure Ph, the work of compressing a part of the refrigerant from the low pressure Pl to the intermediate pressure Pm can be reduced, and high efficiency operation can be performed. it can.

  When the scroll compressor is applied, the injected gas refrigerant is carried out via the injection port 21 in FIG. In the case of the scroll compressor, if the injection port 21 is provided in the second compression chamber 19b from the outside in FIG. 7, no rotation angle can be established for either suction or discharge. Therefore, the injected refrigerant does not flow out to the low pressure side, and the high pressure refrigerant does not flow backward through the injection port, so there is no need for an accessory such as a shut-off valve according to the rotation angle. A corresponding compressor 3 can be configured.

Moreover, the capacity | capacitance control range of the compressor 3 can also be expanded by changing the refrigerant | coolant flow volume which flows through an economizer circuit. When the opening degree of the bypass expansion valve 10 is controlled to be small, the amount of refrigerant flowing through the economizer circuit is reduced. At this time, the flow rate of refrigerant discharged from the compressor 3 decreases, so the flow rate of refrigerant flowing through the heat exchanger serving as a condenser and the flow rate of refrigerant flowing through the water heat exchanger 9 when performing a heating operation are reduced. 1 heating capacity can be reduced.
Further, when the amount of refrigerant flowing through the economizer circuit decreases, the amount of heat exchange in the supercooling heat exchanger 7 decreases, so that the enthalpy change width (ΔH in FIG. 2) on the high pressure liquid side in the supercooling heat exchanger 7 is small. Thus, the enthalpy (point D in FIG. 2) at the inlet of the evaporator is increased. Therefore, the enthalpy difference (ΔHe in FIG. 2) in the evaporator is reduced, and the amount of heat exchange in the evaporator is reduced. Therefore, in the cooling operation, the heat exchange amount of the water heat exchanger 9 acting as an evaporator is reduced, so that the cooling capacity of the heat source device 1 can be reduced.
Since the flow rate of the refrigerant flowing through the economizer circuit is about 0% to 20% of the compressor suction flow rate, the lower limit capacity of the compressor 3 can be increased by about 20% at the maximum.

  Since the capacity control range of the compressor 3 can be expanded by changing the flow rate of the refrigerant flowing through the economizer circuit as described above, the capacity control range corresponding to the number of heat source machines is expanded. In this invention, the operating condition and operating range in which the heat source machine must be started and stopped by starting the compressor by the inverter is narrowed, but the range is further expanded by performing flow rate control in the economizer circuit. Can do. Therefore, the frequency at which the compressor 3 starts and stops can be reduced, the reliability can be improved, and the load followability can be improved.

Moreover, in this invention, the liquid medium flow path is comprised so that liquid media, such as cold / hot water supplied from the indoor unit 2, may flow through each heat source unit 1 in series. As a result, the following effects can be obtained.
If the liquid medium such as cold / hot water supplied from the indoor unit 2 is configured to flow through the heat source units 1 in parallel, the temperature of the cold / warm water fed from the water storage tank 13 to the indoor unit 2 is stabilized. The cold / hot water outlet temperature in each heat source unit 1 needs to be controlled to be the same in each heat source unit 1. Since the amount of water supplied to each heat source unit 1 at that time is determined by the pump capacity outside the heat source unit 1, depending on the operating conditions, the amount of water supplied is large when starting the heat source unit, and high capacity operation is started from the start. The situation that must be performed occurs, the start-up load of the compressor 3 becomes excessive, and the reliability of the compressor 3 may be reduced.
When the liquid medium flow path is configured such that a liquid medium such as cold / hot water flows through each heat source unit 1 in series, as described above, the capacity of the heat source unit to be additionally operated is reduced, and the heat source unit to be continuously operated is reduced. By controlling the operating capacity to be high, the capacity at the time of starting the compressor 3 can be reduced, and the reliability of the operation of the compressor 3 can be improved.

  Further, when a liquid medium such as cold / hot water is configured to flow through each heat source unit 1 in parallel, the outlet temperature of the cold / hot water in each heat source unit 1 is the same in each heat source unit 1, for example, 7 ° C. in the cooling operation, heating operation Then, it is set to 45 ° C. or the like. On the other hand, when the liquid medium flow path is configured such that a liquid medium such as cold / hot water flows through each heat source apparatus 1 in series, the water temperature condition of the heat source apparatus 1 connected to the upstream side is high in the cooling operation, for example, 9.5 ° C. Furthermore, it is low in the heating operation, for example, set to 42.5 ° C. At this time, the refrigeration cycle of the heat source unit 1 on the upstream side has a high cold water outlet temperature during the cooling operation, so that the low pressure is high, and during the heating operation, the hot water outlet temperature is low, so the high pressure is low and the operating efficiency is low. Get higher. Therefore, highly efficient operation can be performed even if it sees as the whole apparatus.

  In addition, when a liquid medium such as cold / hot water supplied from the indoor unit 2 is configured to flow through the heat source units 1 in parallel, the liquid medium flows through the heat source unit 1 in parallel. Since the configuration can be low and inexpensive, when the cost is important, the configuration may be such that the liquid medium flows through the heat source units 1 in parallel.

  In this embodiment, an example of an air conditioner that supplies cold / hot water to the load side has been described. However, a water heater that supplies hot water for hot water supply to the load side, and a low-temperature brine that cools a cold warehouse or the like to the load side. Even if it is the refrigeration apparatus to supply, the same effect can be acquired by performing either cooling and heating operation.

  In the present embodiment, the number of heat source devices 1 is two, but may be three or more, and the same effect can be obtained in that case.

In addition, although the number of indoor units 2 is one, it may be configured with two or more, and in that case, the same effect can be obtained. When the indoor unit 2 includes a plurality of units, a valve that closes the inflow of a liquid medium such as cold / hot water into each indoor unit 2 is provided. As the control of the shut-off valve, the indoor air temperature is compared with the set temperature in each indoor unit 2, and when the indoor air temperature is higher than the set temperature by a predetermined value during the cooling operation, or the indoor air temperature is predetermined from the set temperature during the heating operation. When the temperature is lower than the specified value, the shut-off valve is opened, and when the indoor air temperature is lower than the set temperature by a predetermined value during the cooling operation, or when the indoor air temperature is higher than the set temperature by the predetermined value during the heating operation, The control is performed so that the load is adjusted individually in each indoor unit 2.
The water amount control of the pump 12 in this case is configured such that the flow paths flowing from the indoor units 2 to the heat source unit 1 are once aggregated, and a temperature sensor 15r is disposed in that portion so that the temperature here becomes the target value. Controlled.

  When there are a plurality of indoor units 2, load fluctuations are likely to occur due to fluctuations in the number of indoor units 2, and accordingly the heat source unit 1 is likely to start and stop, but in the configuration of the present invention, such a situation However, it is possible to perform an operation in which the start and stop of the heat source device 1 is unlikely to occur, and a more reliable device can be obtained.

  Moreover, the refrigerant to be applied is not limited to R410A, and can be applied to other HFC refrigerants, natural refrigerants such as HC refrigerant, CO2, and NH3. In the case of CO2 refrigerant, it is necessary to ensure the pressure resistance of each refrigerant circuit component because the pressure is high. However, if it is configured with one heat source unit, the volume of each component becomes large, and the pressure resistance specification corresponding to the volume Therefore, the parts 3 such as the compressor 3 require a large thickness and are expensive. If a plurality of small-capacity heat source units 1 are configured as in the present invention, the volume of each component can be reduced, the pressure resistance is increased by that amount, and the thickness of each component can be kept low. Can be configured.

Embodiment 2. FIG.
A second embodiment of the present invention is shown in FIG. FIG. 10 shows a refrigerant circuit configuration of the heat source unit 1a in the second embodiment, and a gas-liquid separator 23a is used instead of the supercooling heat exchanger 7a as an economizer circuit. FIG. 11 is a diagram showing the relationship between the pressure and enthalpy of the refrigeration air conditioner in the second embodiment.
In the second embodiment, the configuration and control other than the refrigerant circuit of the heat source devices 1a and 1b are the same as those in the first embodiment.

In the cooling operation in which the refrigerant circuit is connected in a ring shape and cold water is produced by the water heat exchanger 7a, the compressor 3a, the four-way valve 4a, the air heat exchanger 5a, the check valve 6a, the auxiliary expansion valve 22a, and the gas-liquid separator 23a. The main expansion valve 8a, the check valve 6d, the water heat exchanger 9a, the four-way valve 4a, and the compressor 3a are connected in an annular shape, and the refrigerant flows in this order. The gas refrigerant separated by the gas-liquid separator 23a is branched and injected into the compression chamber of the compressor 3a through the bypass expansion valve 10a.
In the heating operation in which hot water is produced by the water heat exchanger 7, the compressor 3a, the four-way valve 4a, the water heat exchanger 7a, the check valve 6b, the auxiliary expansion valve 22a, the gas-liquid separator 23a, the main expansion valve 8a, the check The valve 6c, the air heat exchanger 5a, the four-way valve 4a, and the compressor 3a are connected in an annular shape, and the refrigerant flows in this order. Also in the heating operation, the gas refrigerant separated by the gas-liquid separator 23a is branched and injected into the compression chamber of the compressor 3a through the bypass expansion valve 10a.
The economizer circuit is configured by a circuit in which the gas refrigerant separated by the gas-liquid separator 23a in the cooling and heating operation is branched and injected into the compression chamber of the compressor 3a through the bypass expansion valve 10a.

The operation of the refrigerant circuit in the cooling operation will be described with reference to FIGS. The flow path of the four-way valve 4a is set in the direction of the solid line in FIG. The high-temperature and high-pressure (Ph) gas refrigerant (point A in FIG. 11) discharged from the compressor 3a flows into the air heat exchanger 5a through the four-way valve 4a and dissipates heat in the air heat exchanger 5a serving as a condenser. It condenses and liquefies (11 points B). The high-pressure liquid refrigerant exiting the air heat exchanger 5a passes through the check valve 6a and is reduced to the intermediate pressure (Pm) by the auxiliary expansion valve 22a to become a two-phase refrigerant (point F in FIG. 11). The two-phase refrigerant flows into the gas-liquid separator 23a, gas-liquid is separated, and the separated liquid refrigerant (point C in FIG. 11) flows into the main expansion valve 8a. The two-phase refrigerant decompressed to a low pressure (Pl) by the main expansion valve 8a (point D in FIG. 11) absorbs heat while evaporating and gasifying in the water heat exchanger 9a that becomes the evaporator through the check valve 6d. Then, the liquid medium is cooled to produce cold water. The refrigerant exiting the water heat exchanger 9a is sucked into the compressor 3a through the four-way valve 4a (point E in FIG. 11). The gas refrigerant (point G in FIG. 11) separated by the gas-liquid separator 23a passes through the bypass expansion valve 10a and is injected into the compression chamber in the middle of compression in the compressor 3a, and compressed from the suction state (point E in FIG. 11). After being mixed with the refrigerant (point H in FIG. 11) (point I in FIG. 11), the refrigerant is compressed to a high pressure (Ph) to become a high-temperature and high-pressure gas refrigerant (point A in FIG. 11).
Next, the operation of the refrigerant circuit in the heating operation will be described. In the heating operation, the flow path of the four-way valve 4a is set in the direction of the dotted line in FIG. The state change of the refrigerant in the heating operation is almost the same as that in the cooling operation, and the state change shown in FIG. The high-temperature and high-pressure (Ph) gas refrigerant (point A in FIG. 11) discharged from the compressor 3a flows into the hydrothermal exchanger 9a via the four-way valve 4a, and dissipates heat in the hydrothermal exchanger 9a serving as a condenser. It condenses and liquefies (point B in FIG. 11). At this time, water as a liquid medium is heated to generate hot water. The high-pressure liquid refrigerant that has exited the water heat exchanger 9a passes through the check valve 6b, and is reduced to the intermediate pressure (Pm) by the auxiliary expansion valve 22a to become a two-phase refrigerant (point F in FIG. 11). The two-phase refrigerant flows into the gas-liquid separator 23a, gas-liquid is separated, and the separated liquid refrigerant (point C in FIG. 11) flows into the main expansion valve 8a. The refrigerant is reduced to a low pressure (Pl) by the main expansion valve 8a to become a two-phase refrigerant (point D in FIG. 11), passes through the check valve 6c, flows into the air heat exchanger 5a serving as an evaporator, and flows into the air heat exchanger 5a. The gas is evaporated and is sucked into the compressor 3a through the four-way valve 4a (point E in FIG. 11). The gas refrigerant (point G in FIG. 11) separated by the gas-liquid separator 23a passes through the bypass expansion valve 10a and is injected into the compression chamber in the middle of compression in the compressor 3a, and compressed from the suction state (point E in FIG. 11). After being mixed with the refrigerant (point H in FIG. 11) (point I in FIG. 11), the refrigerant is compressed to a high pressure (Ph) to become a high-temperature and high-pressure gas refrigerant (point A in FIG. 11).

About the control operation in the heat source machine 1 of this Embodiment 2, the step which controls the opening degree of the auxiliary | assistant expansion valve 22 with respect to the said Embodiment 1 is added. Hereinafter, the control operation during the cooling operation will be described with reference to FIG. Also in the control operation, the same operation is performed for the heat source devices 1a and 1b. Therefore, the operation control of the heat source device 1a will be described as a representative.
First, when the heat source unit 1a is activated (ST501), the rotation speed of the compressor 3a, the air flow to the air heat exchanger 5a, the opening of the main expansion valve 8a, and the opening of the bypass expansion valve 10a are set to initial values. Operation is performed (ST502). The initial setting value of the air flow rate of the air heat exchanger 5a is determined by comparing the outside air temperature detected by the temperature sensor 15s and a predetermined value stored in the measurement control device 16 in advance. Here, the predetermined value to be compared with the outside air temperature is determined based on equipment performance such as the operating capacity of the compressor and heat exchanger performance, so that the high pressure of the refrigeration cycle (pressure of the refrigerant discharged from the compressor 3a) does not decrease too much. Therefore, the high air volume is set when the outside air temperature is high, and the low air volume is set when it is low.

  And after driving | running in this state, each actuator is controlled according to an apparatus operating state. First, the rotation speed of the compressor 3 is controlled so that the cold water temperature at the outlet of the hydrothermal exchanger 9 detected by the temperature sensor 15h becomes a preset target value (ST503). As described above, the target temperature differs between the heat source devices 1a and 1b. For example, the target temperature is set to 9.5 ° C. for the heat source device 1a and 7 ° C. for the heat source device 1b. If the rotation speed of the compressor 3 is high, the refrigerant flow rate increases, the cooling capacity of the apparatus increases, and the water is further cooled, so the water temperature at the outlet of the water heat exchanger 9 decreases. Conversely, when the rotation speed of the compressor 3 is low, the water temperature at the outlet of the water heat exchanger 9 rises. Therefore, the water temperature at the outlet of the water heat exchanger 9 is compared with the target value. When the water temperature is high, the rotational speed of the compressor 3 is increased, and when the water temperature is low, the rotational speed of the compressor 3 is decreased (ST504).

  Next, although it is the air flow rate of the air heat exchanger 5, this air flow rate is basically operated at an initial set value. However, if the high pressure detected by the pressure sensor 14b deviates from the predetermined range depending on the operating conditions, it is confirmed whether the high pressure is within the predetermined range (ST505). In order to protect the compressor 3a, control is performed to increase the air volume. If the high pressure is excessively reduced, the low pressure (pressure of the refrigerant sucked by the compressor 3a) is greatly reduced even if the opening degree of the main expansion valve 8 is controlled, the refrigerant evaporation temperature is lowered below the freezing point, Since there is a risk of freezing, control is performed to reduce the air volume so as to suppress an excessive decrease in high pressure (ST506).

Next, the opening degree of the main expansion valve 8a, which is the outlet of the water heat exchanger 9a serving as an evaporator, calculates the refrigerant superheat degree SH in the state of suction of the compressor 3a (point E in FIG. 11) (ST507). ), The refrigerant superheat degree SH is controlled to be a preset target value, for example, 2 ° C. (ST508). Here, the refrigerant superheat degree SH at the outlet of the water heat exchanger 9a and sucked into the compressor 3a is (temperature sensor 15a detected temperature (intake temperature of the compressor 3)) − (refrigerant saturation temperature converted from the pressure sensor 14a). Use the value calculated in.
When the opening of the main expansion valve 8a decreases, the flow rate of the refrigerant flowing through the water heat exchanger 9a decreases, the refrigerant superheat degree SH at the outlet of the water heat exchanger 9a increases, and conversely, the opening of the main expansion valve 8a increases. Then, the refrigerant superheat degree SH of the water heat exchanger 9a becomes small. Therefore, the refrigerant superheat degree SH of the compressor 3a suction (water heat exchanger 9a outlet) is compared with the target value, and when the refrigerant superheat degree SH is larger than the target value, the opening degree of the main expansion valve 8a is largely controlled. When the refrigerant superheat degree SH is smaller than the target value, the opening degree of the main expansion valve 8a is controlled to be small (ST509).

Next, regarding the opening of the auxiliary expansion valve 22a, first, the degree of supercooling SC at the outlet of the air heat exchanger 5a serving as a condenser is calculated (ST510). Specifically, it is calculated by (refrigerant saturation temperature converted from the value detected by the pressure sensor 14b) − (temperature sensor 15c detected temperature). The opening degree of the auxiliary expansion valve 22a is controlled so that the degree of supercooling SC becomes a preset target value, for example, 5 ° C. (ST511).
When the opening degree of the auxiliary expansion valve 22a decreases, the refrigerant flow rate flowing through the air heat exchanger 5a decreases, the degree of supercooling SC at the outlet of the air heat exchanger 5a increases, and conversely the opening degree of the auxiliary expansion valve 22a increases. Then, the degree of supercooling SC of the air heat exchanger 22a becomes small. Therefore, when the degree of supercooling SC is larger than the target value, the opening degree of the auxiliary expansion valve 22a is increased. Conversely, when the degree of supercooling SC is smaller than the target value, the opening degree of the auxiliary expansion valve 22a is decreased ( ST512).

Next, the opening degree of the bypass expansion valve 10a, the refrigerant superheat degree SHd at the outlet of the compressor 3a (point A in FIG. 11) is calculated (ST513), and this refrigerant superheat degree SHd is set to a preset target value. For example, the temperature is controlled to be 2 ° C. (ST514). Here, the refrigerant superheat degree SHd discharged from the compressor 3a uses a value calculated by (temperature sensor 15b detected temperature) − (refrigerant saturation temperature converted from the value detected by the pressure sensor 14b).
When the opening degree of the bypass expansion valve 10a is reduced, the flow rate of the refrigerant flowing through the economizer circuit is reduced, and the refrigerant superheat degree SHd discharged from the compressor 3a is increased (the point A in FIG. 11 moves to the right and the distance between AB is increased). Conversely, when the opening degree of the bypass expansion valve 10a is increased, the refrigerant superheat degree SHd at the outlet of the compressor 3a decreases (the point A in FIG. 11 moves to the left, and the distance between AB decreases). Therefore, the refrigerant superheat degree SHd at the outlet of the compressor 3a is compared with the target value. If the refrigerant superheat degree SHd is larger than the target value, the opening degree of the bypass expansion valve 10a is controlled to be large, and the refrigerant superheat degree SHd is set to the target value. When the value is smaller than the value, the opening degree of the bypass expansion valve 10a is controlled to be small (ST515).
Then, it returns to step ST503 again, it is detected whether the outlet water temperature of the water heat exchanger 9 has become target value, and the process of step ST503-ST515 is repeated according to a detection result.

  Also in the second embodiment, the refrigeration cycle is a gas injection cycle, and high-efficiency operation can be performed as in the first embodiment. Moreover, by controlling the flow rate injected by the opening degree control of the bypass expansion valve 10a, the capacity control range of the heat source unit 1 can be expanded, the frequency of starting and stopping the heat source unit 1 is reduced, and a more reliable device is obtained. be able to.

Embodiment 3 FIG.
A third embodiment of the present invention is shown in FIG. FIG. 13 shows a refrigerant circuit configuration of the heat source unit 1a in the third embodiment. A gas bypass circuit 24 connecting the discharge side and the suction side of the compressor 3 and a flow control valve 25 on the gas bypass circuit 24 are shown. It is provided. Other configurations are the same as those of the first embodiment.

By providing the gas bypass circuit 24, the lower limit of the capacity control range of the compressor 3 can be expanded. During normal operation, the flow control valve 25 is closed to perform the same operation as in the first embodiment, but the flow control valve 25 is opened when it is desired to lower the capacity control range of the compressor 3 below the lower limit of the operation frequency. Then, a part of the refrigerant discharged from the compressor 3 a is caused to flow to the gas bypass circuit 24.
By carrying out like this, the refrigerant | coolant flow rate which flows in into the water heat exchanger 9a can be reduced, and the cooling and heating capability of the heat source unit 1 can be reduced. By expanding the capacity control range of the compressor 3, the frequency of starting and stopping the heat source unit 1 can be reduced, and the reliability of the apparatus can be further increased.

  Further, when the heat source device 1 starts operation and the compressor 3 is activated, the flow control valve 25 may be opened for a predetermined time after activation. As described above, liquid back is likely to occur when the compressor 3 is started. At this time, the high-temperature refrigerant discharged from the compressor 3a is caused to flow to the suction side via the gas bypass circuit 24 and mixed with the liquid-backed refrigerant, thereby evaporating the liquid refrigerant and liquid refrigerant in the liquid-back operation. Reduce the amount. By so doing, liquid compression and refrigeration oil dilution during liquid back operation can be eased, and more reliable operation can be realized.

Embodiment 4 FIG.
Embodiment 4 of the present invention is shown in FIG. FIG. 14 shows a refrigerant circuit configuration of the heat source unit 1a in the fourth embodiment, and a gas bypass circuit 26 for controlling the capacity of the compressor 3a is provided. The gas bypass circuit 26 connects the discharge and suction sides of the compressor 3a and the compression chamber in the compressor 3a, and has flow control valves 25a and 25b on the bypass circuit.
FIG. 15 shows the position of the compression chamber to which one end of the gas pie bus circuit is connected, and one end of the gas pie bus circuit is connected to an unload port 27 provided in the compression chamber 19a on the outer peripheral side of the scroll compressor. The unload port 27 has a structure that can be closed by a leaf spring. When the pressure on the gas pipe circuit 26 side is higher than the pressure in the compression chamber 19a, the leaf spring is pressed against the compression chamber side to close and conversely compress. When the pressure in the chamber 19a is high, the leaf spring opens and the compression chamber 19a and the gas bypass circuit 26 are connected.

By providing the gas bypass circuit 26, the lower limit of the capacity control range of the compressor 3 can be expanded. During normal operation, by opening the flow control valve 25a and closing 25b, the pressure of the gas piping circuit 26 becomes high, the unload port 27 is closed, and the same operation as in the first embodiment is performed.
When it is desired to lower the capacity control range of the compressor 3 below the lower limit of the operating frequency, the flow control valve 25a is closed and 25b is opened. At this time, the unload port 27 is opened and the compression chamber 19a, the gas bypass circuit 26, and the compressor 3 suction side are connected. Therefore, until the unload port 27 is positioned on the outer peripheral side of the orbiting scroll 17, the outermost compression is performed. The chamber 19a is connected to the suction side and is not compressed. When the unload port 27 is positioned on the outer peripheral side of the orbiting scroll 17, the compression of the outermost compression chamber 19a is completed, and the compression starts from this point, so the stroke volume of the compressor 3a is reduced, The lower limit of the capacity control range of the compressor 3a is expanded.
By carrying out like this, the refrigerant | coolant flow rate which flows in into the water heat exchanger 9a can be reduced, and the cooling and heating capability of the heat source unit 1 can be reduced. By expanding the capacity control range of the compressor 3a, the frequency of starting and stopping the heat source unit 1 can be reduced, and the reliability of the apparatus can be further increased.
In the third embodiment, since the compressed refrigerant is bypassed to the suction side, the amount of unnecessary compression work is reduced and the operation efficiency is reduced. Thus, the compression chamber and the suction side are connected in this way, When the closing position is delayed, there is little compression work for the refrigerant flowing out through the bypass circuit 26, and the lower limit of the capacity control range can be expanded more efficiently.

1a, 1b Heat source unit 2 Indoor unit 3a, 3b Compressor 4a, 4b Four-way valve 5a, 5b Air heat exchanger 6a, 6b, 6c, 6d, 6e, 6f, 6g, 6h Check valve 7a, 7b Supercooling heat exchange 8a, 8b Main expansion valves 9a, 9b Hydrothermal exchangers 10a, 10b Bypass expansion valve 11 Indoor heat exchanger 12 Pump 13 Water tanks 14a, 14b, 14c, 14d Pressure sensors 15a, 15b, 15c, 15d, 15e, 15f 15g, 15h, 15i, 15j, 15k, 15l, 15m, 15n, 15o, 15p, 15q, 15r, 15s, 15t, 15u Temperature sensor 16 Measurement control device 17 Oscillating scroll 18 Fixed scroll 19, 19a, 19b, 19c Compression chamber 20 Discharge port 21 Injection port 22 Auxiliary expansion valve 23 Gas-liquid separators 24, 26 Gas bypass circuit 25,25a, 25b flow control valve 27 unload port

Claims (11)

A scroll compressor that is driven by an inverter and compresses the refrigerant;
An air heat exchanger connected to the scroll compressor and performing heat exchange between the refrigerant and air;
A pressure reducing device connected to the air heat exchanger and reducing the pressure of the refrigerant;
A load-side heat exchanger having one end connected to the decompression circuit and the other end connected to the scroll compressor and supplying cold to a heat load by performing heat exchange between the liquid medium and the refrigerant; A plurality of heat source machines having
The refrigerating and air-conditioning apparatus, wherein the liquid medium flows through the heat source devices in series. The said scroll compressor is provided with the port by which gas injection is performed, and the economizer circuit which supplies the gas of the pressure between the high pressure of the refrigerating cycle of the said refrigerating and air-conditioning apparatus to the port is provided to this port. The refrigeration air conditioner according to 1. 3. A gas bypass circuit for connecting a discharge side and a suction side of the compressor, and a flow rate control valve for controlling a flow rate of the refrigerant flowing through the gas bypass circuit. Refrigeration air conditioner of description. 3. A gas bypass circuit that connects a compression chamber of the compressor and a compressor suction side, and a flow rate control valve that controls a flow rate of the refrigerant flowing through the gas bypass circuit. The refrigeration air conditioner described in 1. 2. The refrigeration according to claim 1, wherein the decompression device includes an opening adjustment valve, and includes a flow control valve that fully closes the opening of the opening adjustment valve while the compressor is stopped. Air conditioner. When operating at least two or more of the heat source units, the total capacity of the compressors of the heat source unit performing the operation is equal to or less than a predetermined ratio of the total maximum capacity of the compressors of the heat source unit performing the operation. 6, the refrigeration air conditioner according to claim 1, wherein the operation of at least one of the heat source machines is stopped. When one or a plurality of the heat source units are operating, and when at least one of the heat source units is stopped, the total capacity of the compressors of the heat source units performing the operation is operating. The refrigerating and air-conditioning apparatus according to claim 1 or 6, wherein the operation of the heat source apparatus that has been stopped is started when the total capacity of the compressors of the heat source apparatus is equal to or greater than a predetermined ratio. When starting the operation of the heat source machine that has been stopped, the capacity of the scroll compressor of the heat source machine is already in operation for a predetermined period from the start of operation of the heat source machine. It controls so that it may become smaller than a capacity | capacitance, The refrigeration air conditioner of Claim 7 characterized by the above-mentioned. 2. The control according to claim 1, wherein when operating a plurality of the heat source units at the same time, the temperature difference at the inlet / outlet of the load-side heat exchanger of the liquid medium is controlled to be substantially the same in each heat source unit. Refrigeration air conditioner of description. The economizer circuit is:
A bypass expansion valve that depressurizes a part of the refrigerant provided by branching from a connection path between the air heat exchanger and the pressure reducing device;
A supercooling heat exchanger that performs heat exchange between the refrigerant passing through the connection path between the air heat exchanger and the pressure reducing device, and the refrigerant passing through the bypass expansion valve;
The refrigerating and air-conditioning apparatus according to claim 2, comprising a refrigerant pipe that introduces the refrigerant that has passed through the bypass expansion valve and the supercooling heat exchanger into the port. The economizer circuit is:
A gas-liquid separation device provided between the air heat exchanger and the decompression device;
A bypass expansion valve for further reducing the pressure of the gas separated by the gas-liquid separator;
Piping connecting the bypass expansion valve and the port of the scroll compressor;
The refrigerating and air-conditioning apparatus according to claim 2, further comprising: a pipe that introduces the liquid separated by the gas-liquid separation apparatus into the decompression apparatus.

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