EP3967949B1

EP3967949B1 - Heat source system

Info

Publication number: EP3967949B1
Application number: EP20805173.0A
Authority: EP
Inventors: ShuoBing YANG; Takeru Morita
Original assignee: Carrier Japan Corp
Current assignee: Carrier Japan Corp
Priority date: 2019-05-14
Filing date: 2020-04-27
Publication date: 2025-01-29
Anticipated expiration: 2040-04-27
Also published as: EP3967949A1; KR102637381B1; JP7130864B2; EP3967949A4; JPWO2020230603A1; WO2020230603A1; KR20210153728A

Description

Technical Field

Embodiments of the present invention described herein relate generally to heat source systems.

Background Art

A technique in which an outdoor unit includes a heat exchanger used to carry out heat exchange between a refrigerant and outdoor air, compressor used to compress the refrigerant, heater used to heat the compressor, outdoor air temperature detector used to detect the outdoor air temperature, and control device and, when the operation of the compressor is stopped, the control device makes the heating control of the compressor using the heater switchable in a multi-step manner on the basis of the outdoor air temperature detected by the outdoor air temperature detector to thereby prevent a refrigerant stagnation phenomenon from occurring is known. Here, the term stagnation phenomenon implies a phenomenon in which after the operation of the compressor is stopped, the refrigerant collects inside the casing of the compressor the temperature of which has lowered to condense and then merges into the refrigeration machine oil inside the casing. JP 2014-126309 1 discloses a heat source system.
US 2013/0199224 A1 discloses that a heat source system which executes air conditioning by refrigerating cycles comprises an outdoor air temperature measuring unit which is configured to measure an outdoor air temperature, heating units each of which is configured to heat compressors used for the refrigerating cycles, memory units each of which is configured to store a relationship between a temperature difference between an outdoor air temperature measured by the outdoor air temperature measuring unit and a refrigerant saturation temperature at the time of saturation of each refrigerant of the refrigerating cycles and an energization ratio of an intermittent operation period of each of the heating units, and first controllers each of which is configured to calculate, at the time when each of the compressors is in a stopped state, the temperature difference between the outdoor air temperature measured by the outdoor air temperature measuring unit and the refrigerant saturation temperature at the time of saturation of each refrigerant of the refrigerating cycles, determine an energization ratio of the intermittent operation period on the basis of this calculation result and the relationship stored in each of the memory units, and execute heating control of each of the heating units according to the determined energization ratio of the intermittent operation period.
EP 1 995 536 A1 discloses an air conditioner provided with a plurality of outdoor units, an indoor unit, a liquid refrigerant communication pipe and gas refrigerant communication pipe, and a controller. The outdoor unit has a compressor, an outdoor heat exchanger, and an accumulator. The indoor unit has an indoor expansion valve and an indoor heat exchanger. The controller starts another of the heat source units in a stopped state when it is determined that the amount of refrigerant is excessive in a heat source unit in an operating state, or performs refrigerant accumulation control for accumulating refrigerant in an accumulator in a heat source unit other than a first heat source unit in an operating state.
EP 3 467 395 A1 discloses a heat source system control method, wherein a control section of a heat source system controls the number of heat source machines to be operated and an amount of adjustment of each of flow rate regulating valves according to the required performance of air heat exchangers, identifies groups each of which includes air heat exchangers in operation from an operational status of a plurality of air heat exchangers, selects one set of piping resistance characteristics from a plurality of sets of piping resistance characteristics of the identified groups, controls an amount of adjustment of a pressure-regulating valve in such a manner that a pressure difference sensed by a differential pressure sensor coincides with a pressure difference calculated on the basis of the selected piping resistance characteristics, and controls a pump operation frequency of each of the heat source machines in operation on the basis of a sensed flow rate of a flow rate sensor.

Summary of Invention

Technical Problem

Incidentally, there are also cases where the outdoor air temperature detected by the outdoor air temperature detector and actual temperature of the compressor are different from each other. In order to cope with such a case, it is conceivable that when the heating control of the compressor is switched over, control may be carried out in such a manner as to cope with the severest environmental condition. Although when the heating control is executed in such a manner, it becomes possible to cope with even the case where the severest environmental condition is imposed, on the other hand, in the case where the severest environmental condition is not imposed, the compressor is subjected to excessive heating control. In such circumstances, useless electric power is wasted on the heating control of the compressor.
The purpose of the present invention described herein aim to acquire a heat source system capable of appropriately preventing a refrigerant stagnation phenomenon from occurring, and further reducing the power consumption of the compressor heating control.

Solution to Problem

According to one aspect of the present invention, as defined by appended independent claim 1, a heat source system which executes air conditioning by refrigerating cycles comprises an outdoor air temperature measuring unit which is configured to measure an outdoor air temperature, heating units each of which is configured to heat compressors used for the refrigerating cycles, memory units each of which is configured to store a relationship between a temperature difference between an outdoor air temperature measured by the outdoor air temperature measuring unit and a refrigerant saturation temperature at the time of saturation of each refrigerant of the refrigerating cycles and an energization ratio of an intermittent operation period of each of the heating units, and first controllers each of which is configured to calculate, at the time when each of the compressors is in a stopped state, the temperature difference between the outdoor air temperature measured by the outdoor air temperature measuring unit and the refrigerant saturation temperature at the time of saturation of each refrigerant of the refrigerating cycles, determine an energization ratio of the intermittent operation period on the basis of this calculation result and the relationship stored in each of the memory units, and execute heating control of each of the heating units according to the determined energization ratio of the intermittent operation period. The heat source system further comprises refrigerant temperature measuring units each of which is configured to measure a refrigerant temperature of the refrigerant discharged from each of the compressor, wherein each of the memory units is configured to further store therein first information indicating a relationship between a temperature of each of the compressors and the refrigerant temperature measured by each of the refrigerant temperature measuring units, and each of the first controllers is configured to estimate, before an operation of each of the compressors, the temperature of each of the compressors from the refrigerant temperature measured by each of the refrigerant temperature measuring units and the first information, calculate a temperature difference between the estimated temperature and a condensation temperature after the operation of each of the compressors estimated from predetermined environmental conditions, when the calculated temperature difference exceeds a set value, start up each of the compressors in a first startup pattern in which a startup securing the reliability of each of the compressors is to be carried out and, when the temperature difference is less than or equal to the set value, start up each of the compressors in a second startup pattern in which a normal startup is to be carried out.
According to another aspect of the present invention, as defined by appended independent claim 3, a heat source system which executes air conditioning by refrigerating cycles comprises an outdoor air temperature measuring unit which is configured to measure an outdoor air temperature, heating units each of which is configured to heat compressors used for the refrigerating cycles, memory units each of which is configured to store a relationship between a temperature difference between an outdoor air temperature measured by the outdoor air temperature measuring unit and a refrigerant saturation temperature at the time of saturation of each refrigerant of the refrigerating cycles and an energization ratio of an intermittent operation period of each of the heating units, and first controllers each of which is configured to calculate, at the time when each of the compressors is in a stopped state, the temperature difference between the outdoor air temperature measured by the outdoor air temperature measuring unit and the refrigerant saturation temperature at the time of saturation of each refrigerant of the refrigerating cycles, determine an energization ratio of the intermittent operation period on the basis of this calculation result and the relationship stored in each of the memory units, and execute heating control of each of the heating units according to the determined energization ratio of the intermittent operation period. The heat source system further comprises refrigerant temperature measuring units each of which is configured to measure a refrigerant temperature of the refrigerant discharged from each of the compressors, wherein each of the memory units is configured to further store therein first information indicating a relationship between the temperature of each of the compressors and the refrigerant temperature measured by each of the refrigerant temperature measuring units, and each of the first controllers is configured to estimate, before the operation of each of the compressors, the temperature of each of the compressors from the refrigerant temperature measured by each of the refrigerant temperature measuring units and the first information, calculate a temperature difference between the estimated temperature and the refrigerant saturation temperature, when the calculated temperature difference becomes less than a set value, start up each of the compressors in a first startup pattern in which a startup securing the reliability of each of the compressors is to be carried out and, when the temperature difference does not become less than the set value, start up each of the compressors in a second startup pattern in which a normal startup is to be carried out.

Brief Description of Drawings

FIG. 1 is a perspective view showing an example of a heat source system according to a first embodiment.
FIG. 2 is a view showing an example of the control configuration of the heat source system according to the first embodiment.
FIG. 3 is a view showing an example of the configuration of a refrigerating cycle according to the first embodiment.
FIG. 4 is a view showing an example of a relationship between a temperature difference between the refrigerant saturation temperature and outdoor air temperature and intermittent operation ratio according to the first embodiment.
FIG. 5 is a view showing an example of an intermittent operation ratio according to the first embodiment.
FIG. 6 is flowchart showing an example of the processing of intermittent operation control according to the first embodiment.
FIG. 7 is a view showing an example of the configuration of a first controller according to a second embodiment.
FIG. 8 is a view showing an example of startup control of the compressor according to the second embodiment.
FIG. 9 is a view for explaining the case where two startup patterns according to the second embodiment are utilized.
FIG. 10 is a view showing an example of the configuration of a first controller according to a third embodiment.
FIG. 11 is a view showing an example of startup control of the compressor according to the third embodiment.

Mode for Carrying Out the Invention Embodiments of the present invention will be described below with reference to the accompanying drawings.

(First Embodiment)

FIG. 1 is a perspective view showing an example of a heat source system 10 which is an air-cooling type heat pump chilling device configured to produce cold water or warm water.
In the heat source system 10, three air-cooling type heat pump chilling units 11, 12, and 13 are arranged adjacent to each other in the lateral direction. The heat source system 10 is an example of a heat source system, and can be operated in the cooling mode and heating mode. It should be noted that, although, in this embodiment, the heat source system 10 is described about the case where the heat source system 10 includes the three air-cooling type heat pump chilling units 11, 12, and 13, the heat source system 10 may also be configured in such a manner as to include two or four or more air-cooling type heat pump chilling units. Further, the heat source system 10 is installed on a horizontal installation surface such as a roof terrace of a building.
A housing 2 of the air-cooling type heat pump chilling unit is formed into approximately a box-like shape having a depth dimension greater than the width dimension. Here, the air-cooling type heat pump chilling unit of this embodiment includes four refrigerating cycle circuits each of which is formed by connecting in sequence a compressor, four-way valve, air heat exchanger (outdoor heat exchanger), expanding device, and water heat exchanger to each other by refrigerant piping. The refrigerating cycle circuit will be described later with reference to FIG. 3. The housing 2 of this embodiment is constituted of an upper structure 21 and lower structure 22. The upper structures 21 are configured in such a manner that four circuits 11a to 11d, 12a to 12d, and 13a to 13d each of which includes air heat exchangers and other constituent members for each refrigerating cycle circuit are respectively arranged in the longitudinal direction of the air-cooling type heat pump chilling units 11, 12, and 13.
Next, an example of the control configuration of the heat source system 10 will be described below with reference to FIG. 2.
As shown in FIG. 2, control units 111, 112, and 113 are respectively provided in such a manner as to correspond to the air-cooling type heat pump chilling units 11, 12, and 13. It should be noted that configurations common to and possessed by the three control units 111, 112, and 113 are denoted by reference symbols identical to each other and detailed descriptions of the configurations are omitted.
Each of the control units 111, 112, and 113 includes a first controller 120, first refrigerant circuit RA, second refrigerant circuit RB, third refrigerant circuit RC, and fourth refrigerant circuit RD. The control unit 112 further includes a second controller 130 in addition to these configurations. It should be noted that each of the first to fourth refrigerant circuits RA to RD includes elements necessary for the refrigerating cycle such as a compressor, heat exchangers, and the like.
Further, the first controller 120 includes a memory 121. The memory 121 is a nonvolatile memory medium such as a flash ROM. This memory 121 includes a first area 122 in which information such as a relationship or the like between the refrigerant saturation temperature at the time of saturation of the refrigerant and energization ratio of the intermittent operation period corresponding to the temperature difference between the refrigerant saturation temperature and outdoor air temperature is stored, the relationship being used by the first controller 120 in executing the heating control of the compressor. Here, the refrigerant saturation temperature is calculated by using a conversion formula on the basis of, for example, a pressure measured by a pressure sensor configured to detect the pressure inside the refrigerating cycle circuit.
As shown in FIG. 2, the first refrigerant circuit RA, second refrigerant circuit RB, third refrigerant circuit RC, and fourth refrigerant circuit RD are controlled according to an instruction from the first controller 120.
It should be noted that a relay unit or the like may be made to intervene between the first controller 120 and each of the first to fourth refrigerant circuits RA, RB, RC, and RD.
The second controller 130 is connected to the first controller 120 in the control unit 112, and to the first controller 120 in each of the control units 111 and 113. Furthermore, the second controller is connected to an operation panel 140. The second controller 130 outputs an instruction to each of the three first controllers 120 on the basis of a condition set by the operator through the operation panel 140 and state or the like of a load (illustration omitted) connected to the heat source system 10 to thereby operate the heat source system 10 in the cooling mode and heating mode.
Furthermore, the second controller 130 is connected to an outdoor air temperature measuring unit (outdoor air temperature measuring device) 150. The outdoor air temperature measuring unit 150 is a device configured to measure the temperature of the air outside the heat source system 10. The temperature measured by the outdoor air temperature measuring unit 150 is sent to the second controller 130 and is further transmitted from the second controller to each of the three first controllers 120. It should be noted that the configuration may also be contrived in such a manner that the measured outdoor air temperature is directly transmitted from the outdoor air temperature measuring unit 150 to the three first controllers 120. Further, the outdoor air measuring unit 150 may also be provided in each of the air-cooling type heat pump chilling units 11, 12, and 13.
FIG. 3 is a view showing an example of the configuration of refrigerating cycles of each of the air-cooling type heat pump chilling units 11, 12, and 13.
A refrigerant discharged from a compressor 21 flows into air heat exchangers 23a and 23b through a four-way valve 22, the refrigerant passing through the air heat exchangers 23a and 23b flows into a first refrigerant flow path of a water heat exchanger 30 through electronic expansion valves 24a and 24b. The refrigerant passing through the first refrigerant flow path of the water heat exchanger 30 is sucked into the compressor 21 through the four-way valve 22 and accumulator 25. This refrigerant flow direction is the direction at the time of the cooling operation (coldwater producing operation), the air heat exchangers 23a and 23b function as a condenser, and first refrigerant flow path of the water heat exchanger 30 functions as an evaporator. At the time of the heating operation (warm-water producing operation), the flow path of the four-way valve 22 changes to reverse the flow of the refrigerant, the first refrigerant flow path of the water heat exchanger 30 functions as a condenser, and air heat exchangers 23a and 23b function as an evaporator.
The compressor 21, four-way valve 22, air heat exchangers 23a and 23b, electronic expansion valves 24a and 24b, first refrigerant flow path of the water heat exchanger 30, and accumulator 25 constitute a first heat pump refrigerating cycle.
A refrigerant discharged from a compressor 41 flows into air heat exchangers 43a and 43b through a four-way valve 42, the refrigerant passing through the air heat exchangers 43a and 43b flows into a second refrigerant flow path of the water heat exchanger 30 through electronic expansion valves 44a and 44b. The refrigerant passing through the second refrigerant flow path of the water heat exchanger 30 is sucked into the compressor 41 through the four-way valve 42 and accumulator 45. This refrigerant flow direction is the direction at the time of the cooling operation (coldwater producing operation), the air heat exchangers 43a and 43b function as a condenser, and second refrigerant flow path of the water heat exchanger 30 functions as an evaporator. At the time of the heating operation (warm-water producing operation), the flow path of the four-way valve 42 changes to reverse the flow of the refrigerant, the second refrigerant flow path of the water heat exchanger 30 functions as a condenser, and air heat exchangers 43a and 43b function as an evaporator.
The compressor 41, four-way valve 42, air heat exchangers 43a and 43b, electronic expansion valves 44a and 44b, second refrigerant flow path of the water heat exchanger 30, and accumulator 45 constitute a second heat pump refrigerating cycle.
A refrigerant discharged from a compressor 51 flows into air heat exchangers 53a and 53b through a four-way valve 52, the refrigerant passing through the air heat exchangers 53a and 53b flows into a first refrigerant flow path of a water heat exchanger 60 through electronic expansion valves 54a and 54b. The refrigerant passing through the first refrigerant flow path of the water heat exchanger 60 is sucked into the compressor 51 through the four-way valve 52 and accumulator 55. This refrigerant flow direction is the direction at the time of the cooling operation (coldwater producing operation), the air heat exchangers 53a and 53b function as a condenser, and first refrigerant flow path of the water heat exchanger 60 functions as an evaporator. At the time of the heating operation (warm-water producing operation), the flow path of the four-way valve 52 changes to reverse the flow of the refrigerant, the first refrigerant flow path of the water heat exchanger 60 functions as a condenser, and air heat exchangers 53a and 53b function as an evaporator.
The compressor 51, four-way valve 52, air heat exchangers 53a and 53b, electronic expansion valves 54a and 54b, first refrigerant flow path of the water heat exchanger 60, and accumulator 55 constitute a third heat pump refrigerating cycle.
A refrigerant discharged from a compressor 71 flows into air heat exchangers 73a and 73b through a four-way valve 72, the refrigerant passing through the air heat exchangers 73a and 73b flows into a second refrigerant flow path of the water heat exchanger 60 through electronic expansion valves 74a and 74b. The refrigerant passing through the second refrigerant flow path of the water heat exchanger 60 is sucked into the compressor 71 through the four-way valve 72 and accumulator 75. This refrigerant flow direction is the direction at the time of the cooling operation (coldwater producing operation), the air heat exchangers 73a and 73b function as a condenser, and second refrigerant flow path of the water heat exchanger 60 functions as an evaporator. At the time of the heating operation (warm-water producing operation), the flow path of the four-way valve 72 changes to reverse the flow of the refrigerant, the second refrigerant flow path of the water heat exchanger 60 functions as a condenser, and air heat exchangers 73a and 73b function as an evaporator.
The compressor 71, four-way valve 72, air heat exchangers 73a and 73b, electronic expansion valves 74a and 74b, second refrigerant flow path of the water heat exchanger 60, and accumulator 75 constitute a fourth heat pump refrigerating cycle.
The water inside the water piping 2b is guided to the water piping 2a through a water flow path of the water heat exchanger 60 and water flow path of the water heat exchanger 30.
A pump 80 is arranged in the water piping between the water piping 2b and water flow path of the water heat exchanger 60. The pump 80 includes a motor operated by an AC voltage supplied from an inverter 81, and the pump head varies according to the rotational speed of the motor. The inverter 81 rectifies a voltage of the commercial AC power, converts the rectified DC voltage into an AC voltage of a predetermined frequency by switching, and supplies the converted AC voltage as the drive power of the motor of the pump 80. By changing the frequency (operation frequency) F of the output voltage of the inverter 81, the rotational speed of the motor of the pump 80 is changed.
A differential pressure sensor 90 is arranged between the water piping of the water heat exchanger 60 on the water inflow side and water piping of the water heat exchanger 30 on the water outflow side. The differential pressure sensor 90 detects a difference (water pressure difference between the water heat exchangers 60 and 30) between the pressure of the water flowing into the water heat exchanger 60 and pressure of the water flowing out of the water heat exchanger 30. On the basis of the detected differential pressure of the differential pressure sensor 90, it is possible to detect the quantity of the water flowing through each of the water heat exchangers 60 and 30, i.e., the quantity of the water flowing through the heat source equipment.
Further, a heater wire (hereinafter referred to as a "case heater") 21a, 41a, 51a, and 71a which is a heating unit is wound around the outside of each compressor 21, 41, 51, and 71. Each of the case heaters 21a, 41a, 51a, and 71a is provided for the purpose of heating each of the compressors 21, 41, 51, and 71. The first controller 120 heating-controls the case heaters 21a, 41a, 51a, and 71a separately from each other to thereby heat each of the compressors 21, 41, 51, and 71.
Furthermore, on the discharge side of each of the compressors 21, 41, 51, and 71, each of temperature sensors S1 to S4 which are refrigerant temperature measuring units is provided. Each of the temperature sensors S1 to S4 measures the temperature inside each of the compressors 21, 41, 51, and 71 on the discharge side, and first controller 120 estimates the temperature of each of the compressors 21, 41, 51, and 71 on the basis of each measured temperature. It should be noted that although when the operation of each of the compressors 21, 41, 51, and 71 is in the stopped state, the refrigerant is not discharged, it becomes possible to detect the temperature of the refrigerant inside each of the compressors 21, 41, 51, and 71 by the temperature conducted by heat conduction. The temperature values measured by the temperature sensors S1 to S4 are used in the second and third embodiments to be described later.
The first controller 120 calculates, when the operation of each of the compressors 21, 41, 51, and 71 is in the stopped state, a temperature difference between the outdoor air temperature measured by the outdoor air temperature measuring unit 150 and refrigerant saturation temperature at the time of saturation of the refrigerant, determines the energization ratio of the intermittent operation period on the basis of the above calculation result and relationship stored in the first memory 121 described previously, and executes the heating control of each of the compressors 21, 41, 51, and 71, i.e., each of the case heaters 21a, 41a, 51a, and 71a on the basis of the determined energization ratio. Details of the heating control of the case heater to be executed by the first controller 120 will be described later.
FIG. 4 is a view showing a relationship between a temperature difference between the refrigerant saturation temperature and outdoor air temperature and enerigization ratio r of the intermittent operation.
The first controller 120 acquires, when the operation of each of the compressors 21, 41, 51, and 71 is in the stopped state, the outdoor air temperature through the outdoor air temperature measuring unit 150 and second controller 130, calculates the temperature difference between the acquired outdoor air temperature and refrigerant saturation temperature, and calculates the enerigization ratio of the intermittent operation period from this temperature difference by utilizing the relationship shown in FIG. 4. Then, on the basis of the energization ratio of the intermittent operation period, the first controller 120 executes heating control of each of the case heaters 21a, 41a, 51a, and 71a.
Further, FIG. 5 is a view showing an example of an intermittent operation ratio.
In FIG. 5, the axis of ordinate indicates the on/off state of the heating control of the case heater 21a, and axis of abscissas indicates time. The period Ts of the intermittent operation is set at a predetermined time (for example, in this embodiment, 30 minutes), during the elapse of a first time period T1 which is a part of the predetermined time, heating of the case heater 21a is kept in the off-state and, after the elapse of the first time period T1 and during the elapse of a second time period T2, heating of the case heater 21a is kept in the on-state. That is, the relationship between the intermittent operation period Ts and time periods T1 and T2 is TS=T1+T2, and the energization ratio r of the intermittent operation is T2/Ts. The first time period T1 has a relationship "T1=(1-r)·Ts" with the intermittent operation period Ts and ratio r, and second time period T2 has a relationship "T2=r·Ts" with the intermittent operation period Ts and ratio r. It should be noted that such determination of the first time period T1 and second time period T2 of the intermittent operation period Ts, and intermittent operation ratio r is carried out also with respect to each of the other case heaters 41a, 51a, and 71a in the same manner as above.
Next, intermittent operation control will be described below. FIG. 6 is flowchart showing an example of the processing of intermittent operation control to be executed by the first controller 120. This processing is executed at predetermined time intervals and is executed each time, for example, one second elapses. It should be noted that although this processing is executed with respect to each of the compressors 21, 41, 51, and 71, hereinafter, in order to simplify the description, only the processing to be executed with respect to the compressor 21 will be described.
The first controller 120 determines whether or not the compressor 21 is in operation (ST101). Upon determination that the compressor 21 is not in operation (ST101: NO), the first controller 120 starts addition of an addition timer, calculates the energization ratio r of the intermittent operation as described previously, and calculates the first time period T1 and second time period T2 corresponding to the operation period Ts and energization ratio r (ST102). Here, the addition timer is formed inside, for example, the memory 121. This addition timer is used to determine whether or not the current point in time is, for example, within the second time (second time period) T2 after the elapse of the already-described first time (first time period) T1, i.e., to determine whether or not the heating control of the case heater 21a has already been started.
Next, the first controller 120 determines whether or not the addition timer value is greater than the already-described intermittent operation period Ts (ST103). Upon determination that the addition timer value is less than the intermittent operation period Ts (ST103: NO), the first controller 120 determines whether or not the addition timer value is greater than the calculated first time period T1 (ST104). When the addition timer value is less than the first time period T1 (ST104: NO), the first controller 120 brings the case heater 21a into the off-state without carrying out heating control (ST105), and returns to the determination (ST101) whether or not the compressor 21 is in operation. Further, when the addition timer value is greater than the first time period T1 (ST104: YES), the first controller 120 brings the case heater 21a into the on-state to thereby carry out heating control (ST106), and then returns to the determination (ST101) whether or not the compressor 21 is in operation.
Then, the processing is returned to the processing (ST101) of determining whether or not the compressor 21 is in operation and, when the compressor 21 is not in operation (ST101: NO), the first controller 120 continues carrying out the heating control of the case heater 21a until the addition timer value reaches the intermittent operation period Ts. Then, when the addition timer value reaches the intermittent operation period Ts (ST103: YES), the first controller 120 brings the case heater 21a into the off-state, and resets the addition timer value (ST107). Then, the processing is returned to the processing (ST101) of determining whether or not the compressor 21 is in operation, and the above determination is repeated until the compressor 21 starts to operate.
It should be noted that when the compressor 21 is in operation or when the compressor 21 has started to operate (ST101: YES), the first controller 120 brings the case heater 21a into the off-state, resets the addition timer (ST107), and terminates the processing. That is, while the compressor 21 is in operation, heating control of the case heater 21a is not executed.
Owing to the configuration described above, it is possible for the first controller 120 to acquire, when the operation of each of the compressors 21, 41, 51, and 71 is in the stopped state, the outdoor air temperature measured by the outdoor air temperature measuring unit 150, calculates the temperature difference between the acquired outdoor air temperature and refrigerant saturation temperature, determine, on the basis of the above calculation result and relationship stored in the first memory 120a, the intermittent operation period Ts of each of the case heaters 21a, 41a, 51a, and 71a, and execute heating control of each of the case heaters 21a, 41a, 51a, and 71a according to each of the determined periods. The greater the temperature difference between the refrigeration machine oil temperature and refrigerant saturation temperature, the less the stagnation quantity of the refrigerant merging into the refrigeration machine oil becomes and, the less the temperature difference, the greater the stagnation quantity becomes. Further, when the operation of the refrigerating cycle is in the stopped state, the refrigerant saturation temperature is dependent on the lower of the outdoor air temperature which is the ambient temperature of the outdoor heat exchanger and water temperature which is the temperature of the water heat exchanger. That is, the refrigerant saturation temperature varies depending on the influence of the water temperature or outdoor air temperature. On the other hand, the temperature of the refrigeration machine oil lowers depending on the compressor ambient temperature. That is, when the outdoor air temperature is low, the amount of heat radiation from the compressor increases, and hence the case temperature is liable to lower. Accordingly, although the case temperature of the compressor largely varies depending on the season, there is sometimes a case where the variation in the temperature of water to be supplied to the water heat exchanger is little throughout the year, and thus there is sometimes a case where the refrigerant saturation temperature is not dependent on the outdoor air temperature. As described above, in the heat source system configured to carry out heat transfer to the utilization-side equipment by using a utilization-side fluid such as water or the like as in the case of the air-cooling type heat pump chilling unit, the stagnation quantity of the refrigerant merging into the refrigeration machine oil increases/decreases due to the influence of the outdoor air temperature and water temperature of the utilization-side equipment. For example, when the outdoor air temperature is high and saturation temperature is low (water temperature is low), the temperature difference between the refrigeration machine oil temperature and refrigerant saturation temperature is great, whereby a condition making dilution difficult is given, and hence the heat generation amount of the heater can be reduced.
By increasing/decreasing the energization ratio of each of the case heaters 21a, 41a, 51a, and 71a of each of the compressors 21, 41, 51, and 71 according to the temperature difference between the refrigerant saturation temperature and outdoor air temperature as in the case of the present application, it is possible to realize saving of energy and optimization of the necessary energization time.
That is, even in an apparatus in which the temperature of water flowing into the water heat exchanger 30 is approximately constant throughout the year due to the influence of the usage on the utilization side or influence of the source of the supplied water, it is possible to appropriately heat each of the compressors 21, 41, 51, and 71 by each of the case heaters 21a, 41a, 51a, and 71a, appropriately prevent the refrigerant stagnation phenomenon from occurring, and reduce the power consumption of the heating control of each of the compressors 21, 41, 51, and 71.
Further, as described above, by calculating the operation ratio on the basis of the temperature difference between the outdoor air temperature and refrigerant saturation temperature, it is possible to carry out, throughout the year, a stable operation imposing little load on the compressor and requiring only reduced power consumption although the control to be carried out in the operation is simplified.
Further, the control described above is carried out, whereby it is possible to carry out efficient heating control of the compressor saving power consumption without providing a temperature sensor configured to measure the case temperature.
It should be noted that although in the above description, the method in which the intermittent operation period Ts is made the predetermined time, and the first time period during which energization is not to be carried out and second time period during which energization is to be carried out are changed according to the energization ratio r of the intermittent operation is used, in addition to this, the first time period T1 may be made the fixed time, and intermittent operation period Ts and second time period T2 may be changed according to the energization ratio r. Further, the second time period T2 may be made the fixed time, and intermittent operation period Ts and first time period T1 may be changed according to the energization ratio r. When the first time period T1 and second time period T2 are determined according to the energization ratio, each period may be made variable.

(Second Embodiment)

Although in the first embodiment, the processing of heating control of each of the case heaters 21a, 41a, 51a, and 71a at the time when each of the compressors 21, 41, 51, and 71 is in the stopped state has been described, in a second embodiment, processing at the time when each of the compressors 21, 41, 51, and 71 is started up will be described. It should be noted that configurations identical to the first embodiment are denoted by reference symbols identical to the first embodiment, and detailed descriptions of these configurations are omitted.
FIG. 7 is a view showing an example of the configuration of a first controller 120 of the second embodiment. When compared with the first embodiment, the second embodiment differs from the first embodiment in that a second area 123 is provided in a memory 121, and first startup pattern 125a and second startup pattern 125b are added to the first controller 120.
The second area 123 stores therein a relationship between the temperature of each of compressors 21, 41, 51, and 71 and refrigerant temperature (temperature sensor value of the discharged gas) as first information. In this embodiment, the refrigerant temperature is so made as to be acquired from each of temperature sensors S1 to S4 provided on the discharge side of each of the compressors 21, 41, 51, and 71, and the first controller 120 can estimate the temperature of each of the compressors 21, 41, 51, and 71 from the refrigerant temperature measured in this way and already-described first information. Furthermore, the first controller 120 is so made as to be able to calculate a temperature difference between the above estimated temperature and condensation temperature of each of the compressors 21, 41, 51, and 71 estimated from the predetermined environmental conditions, and change the startup pattern of each of the compressors 21, 41, 51, and 71 to one of the first startup pattern 125a and second startup pattern 125b according to the calculated temperature difference.
The first startup pattern 125a is a startup pattern for securing the reliability. That is, the first startup pattern 125a is a startup pattern in which each of the compressors 21, 41, 51, and 71 is made to undergo a high-load operation after the refrigeration machine oil is warmed by carrying out a warm-up operation. On the other hand, the second startup pattern 125b is a normal startup pattern. That is, the second startup pattern is a startup pattern in which each of the compressors 21, 41, 51, and 71 is immediately made to undergo a high-load operation.
Next, startup control of the compressor will be described below. FIG. 8 is a view showing an example of startup control of the compressor 21 to be executed by the first controller 120. It should be noted that the same processing is to be described with respect to each of the other compressors 41, 51, and 71, and hence in this embodiment, descriptions will be given by taking the compressor 21 as an example.
First, the first controller 120 determines whether or not it has become the predetermined time before the startup (ST201). When the determination is 'NO' (ST201: NO), the processing is terminated. That is, until it becomes the predetermined time, a standby state is continued.
Upon determination that it has become the predetermined time (ST201: YES), the first controller 120 acquires the estimated value of the temperature of the compressor 21 (ST202). More specifically, the first controller 120 estimates the temperature of the compressor 21 from the output value (refrigerant temperature) of the sensor S1 and first information stored in the second area 123, and acquires the estimation result as the estimated value.
Next, the first controller 120 estimates the condensation temperature from the environmental conditions such as the outdoor air temperature acquired from the outdoor air temperature measuring unit 150, temperature of the cooling water, and the like, and acquires the estimation result as the estimated value (ST203).
Next, the first controller 120 calculates a temperature difference between the estimated value of the temperature of the compressor 21 and estimated value of the condensation temperature (ST204), and determines whether or not the calculated temperature difference exceeds a set value (ST205). Here, the set value is a threshold used to determine the startup pattern for starting up the compressor 21 and is, for example, a value stored in advance in the second area 123.
Upon determination that the temperature difference exceeds the set value (ST205: YES), the first controller 120 starts up the compressor 21 in the first startup pattern 125a (ST206) and, upon determination that the temperature difference does not exceed the set value (ST205: NO), the first controller 120 starts up the compressor 21 in the second startup pattern 125b (ST207).
FIG. 9 is a view for explaining the two startup patterns. As shown in FIG. 9, the startup patterns are contrived in such a manner that the operation of the compressor 21 is started after an elapse of a short time. Regarding the graphs g1 and g2 of the temperature difference, whereas the graph g1 exceeds the set value with the elapse of time, graph g2 does not exceed the set value. Accordingly, when the temperature difference depicts the graph g1, a startup securing the reliability by the first startup pattern 125a is needed and, when the temperature difference depicts the graph g2, it becomes possible to carry out a startup in the second startup pattern 125b.
The first and second startup patterns 125a and 125b are configured as described above, and hence even when a change occurs in the case temperature or condensation temperature while the compressor 21 is in the stopped state, the first controller 120 can change the startup pattern of the compressor 21 on the basis of whether or not the set value set in advance is exceeded. Accordingly, when the set value is exceeded, by adopting the first startup pattern 125a in which the high-load operation is executed after a warm-up operation is carried out, it becomes possible to allow the dilution degree of the refrigeration machine oil of the compressor 21 in the stopped state to be increased.
Further, the temperature of the compressor 21 is acquired from the temperature sensor S1, and hence it is not necessary to provide a temperature sensor configured to measure the temperature of the compressor 21 itself.

(Third Embodiment)

Although in the first embodiment, the processing of heating control of each of the case heaters 21a, 41a, 51a, and 71a of each of the compressors 21, 41, 51, and 71 in the stopped state has been described, in a third embodiment, the processing to be carried out when each of the compressors 21, 41, 51, and 71 is started up will be described. It should be noted that configurations identical to the first embodiment are denoted by reference symbols identical to the first embodiment, and detailed descriptions of these configurations are omitted.
FIG. 10 is a view showing an example of the configuration of a first controller 120 of the third embodiment. When compared with the first embodiment, the third embodiment differs from the first embodiment in that a third area 124 is provided in a memory 121, and third startup pattern 125c and fourth startup pattern 125d are added to the first controller 120.
The third area 124 stores therein a relationship between the temperature of each of compressors 21, 41, 51, and 71 and refrigerant temperature (temperature sensor value of the discharged gas) as first information. In this embodiment, as in the case of the second embodiment, the refrigerant temperature is so made as to be acquired from each of temperature sensors S1 to S4 provided on the discharge side of each of the compressors 21, 41, 51, and 71, and the first controller 120 can estimate the temperature of each of the compressors 21, 41, 51, and 71 from the refrigerant temperature acquired in the manner described above and already-described first information. Furthermore, the first controller 120 is so made as to be able to estimate the temperature of each of the compressors 21, 41, 51, and 71 from the refrigerant temperature to be measured and first information, calculate a temperature difference between the estimated temperature and refrigerant saturation temperature, and change the startup pattern of each of the compressors 21, 41, 51, and 71 to one of the third startup pattern 125c and fourth startup pattern 125d according to whether or not the calculated temperature difference becomes less than a set value.
The third startup pattern 125c is, as in the case of the first startup pattern 125a, a startup pattern for securing the reliability. That is, the third startup pattern 125c is a startup pattern in which each of the compressors 21, 41, 51, and 71 is made to undergo a high-load operation after the refrigeration machine oil is warmed by carrying out a warm-up operation. On the other hand, the fourth startup pattern 125d is, as in the case of the second startup pattern 125b, a normal startup pattern. That is, the fourth startup pattern is a startup pattern in which each of the compressors 21, 41, 51, and 71 is immediately made to undergo a high-load operation.
Next, startup control of the compressor will be described below. FIG. 11 is a view showing an example of startup control of the compressor 21 to be executed by the first controller 120. It should be noted that the same processing is to be described with respect to each of the other compressors 41, 51, and 71, and hence in this embodiment, descriptions will be given by taking the compressor 21 as an example.
First, the first controller 120 determines whether or not the compressor 21 is in the stopped state (ST301). When the determination result is 'NO' (ST301: NO), the processing is terminated. That is, this control is not executed while the compressor 21 is in operation.
Upon determination that the compressor 21 is in the stopped state (ST301: YES), the first controller 120 acquires an estimated value of the case temperature of the compressor 21 (ST302). The first controller 120 estimates the temperature of the compressor 21 from an output value (refrigerant temperature) of the sensor S1 and first information stored in the third area 124, and acquires the estimation result as the estimated value.
Next, the first controller 120 acquires the refrigerant saturation temperature stored in the first memory 120a (ST303), and calculates the temperature difference between these temperatures (ST304). The temperature differences are stored in sequence in, for example, the third area 124.
Next, the first controller 120 determines whether or not the compressor 21 is to be started (ST305). That is, it is determined whether or not it has become the time for which the startup of the compressor 21 is scheduled. When it is determined by the first controller 120 that the compressor 21 is not to be started (ST305: NO), the processing is returned to step ST302. That is the processing of calculating the temperature difference is executed until the compressor 21 is started up.
On the other hand, upon determination that the compressor 21 is to be started (ST305: YES), the first controller 120 determines whether or not the temperature difference has become less than the set value (ST306). That is, it is determined whether or not there has been a case where the already-described temperature difference has become less than the set value set in advance before the startup of the compressor 21.
Upon determination that there has been the case where the temperature difference has become less than the set value (ST306: YES), the first controller 120 starts up the compressor 21 in the third startup pattern 125c (ST307) and, upon determination that there has not been the case where the temperature difference has become less than the set value (ST306: NO), the first controller 120 starts up the compressor 21 in the fourth startup pattern 125d (ST308).
Owing to the configuration described above, even when a change in the environmental conditions occurs while the compressor 21 is in the stopped state, it is possible for the first controller 120 to change the startup pattern of the compressor 21 on the basis of whether or not there has been the case where the temperature difference has become less than the set value. Accordingly, when there has been the case where the temperature difference has become less than the set value, by adopting the third startup pattern 125c in which the high-load operation is executed after a warm-up operation is carried out, it becomes possible to allow the dilution degree of the refrigeration machine oil of the compressor 21 in the stopped state to be increased.
Further, the temperature of the compressor 21 is acquired from the temperature sensor S1, and hence it is not necessary to provide a temperature sensor configured to measure the temperature of the compressor 21 itself, this being identical to the second embodiment.
While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the invention. Instead, the scope of the invention is only limited by the scope of the appended independent claims.

Reference Signs List

10 ··· air-cooling type heat pump chilling device, 11, 12, 13 ··· air-cooling type heat pump chilling unit, 11a to 11d, 12a to 12d, 13a to 13d ··· circuit, 21, 41, 51, 71 ··· compressor, 21a, 41a, 51a, 71a ··· case heater, 120 ··· first controller, 121 ··· memory, 122 ··· first area, 123 ··· second area, 124 ··· third area, 125a ··· first startup pattern, 125b ··· second startup pattern, 125c ... third startup pattern, 125d ... fourth startup pattern, 130 ··· second controller, 150 ··· outdoor air temperature measuring unit, and T1, T2 ··· time.

Claims

A heat source system which executes air conditioning by refrigerating cycles (RA, RB, RC, RD) comprising:
an outdoor air temperature measuring unit (150) which is configured to measure an outdoor air temperature;

heating units (21a, 41a, 51a, 71a) each of which is configured to heat compressors (21, 41, 51, 71) used for the refrigerating cycles (RA, RB, RC, RD);

memory units (121) each of which is configured to store a relationship between a temperature difference between an outdoor air temperature measured by the outdoor air temperature measuring unit (150) and a refrigerant saturation temperature at the time of saturation of each refrigerant of the refrigerating cycles (RA, RB, RC, RD) and an energization ratio of an intermittent operation period of each of the heating units (21a, 41a, 51a, 71a); and

first controllers (120) each of which is configured to calculate, at the time when each of the compressors (21, 41, 51, 71) is in a stopped state, the temperature difference between the outdoor air temperature measured by the outdoor air temperature measuring unit (150) and the refrigerant saturation temperature at the time of saturation of each refrigerant of the refrigerating cycles (RA, RB, RC, RD) , determine the energization ratio of the intermittent operation period on the basis of this calculation result and the relationship stored in each of the memory units (121), and execute heating control of each of the heating units (21a, 41a, 51a, 71a) according to the determined energization ratio of the intermittent operation period,

characterized in that the heat source system further comprises refrigerant temperature measuring units (S1, S2, S3, S4) each of which is configured to measure a refrigerant temperature of the refrigerant discharged from each of the compressor (21, 41, 51, 71), wherein

each of the memory units (121) is configured to further store therein first information indicating a relationship between a temperature of each of the compressors (21, 41, 51, 71) and the refrigerant temperature measured by each of the refrigerant temperature measuring units (S1, S2, S3, S4), and

each of the first controllers (120) is configured to estimate, before an operation of each of the compressors (21, 41, 51, 71), the temperature of each of the compressors (21, 41, 51, 71) from the refrigerant temperature measured by each of the refrigerant temperature measuring units (S1, S2, S3, S4) and the first information, calculate a temperature difference between the estimated temperature and a condensation temperature after the operation of each of the compressors (21, 41, 51, 71) estimated from predetermined environmental conditions, when the calculated temperature difference exceeds a set value, start up each of the compressors (21, 41, 51, 71) in a first startup pattern in which a startup securing the reliability of each of the compressors (21, 41, 51, 71) is to be carried out and, when the temperature difference is less than or equal to the set value, start up each of the compressors (21, 41, 51, 71) in a second startup pattern in which a normal startup is to be carried out.
The heat source system of claim 1, characterized in that
the period is a predetermined time, and

the first controllers (120) are configured to keep heating of the heating units (21a, 41a, 51a, 71a) in an off-state during a first time period within the predetermined time, and keep the heating of the heating units (21a, 41a, 51a, 71a) in an on-state during a second time period after an elapse of the first time period.
A heat source system which executes air conditioning by refrigerating cycles (RA, RB, RC, RD) comprising:
an outdoor air temperature measuring unit (150) which is configured to measure an outdoor air temperature;

heating units (21a, 41a, 51a, 71a) each of which is configured to heat compressors (21, 41, 51, 71) used for the refrigerating cycles (RA, RB, RC, RD);

memory units (121) each of which is configured to store a relationship between a temperature difference between an outdoor air temperature measured by the outdoor air temperature measuring unit (150) and a refrigerant saturation temperature at the time of saturation of each refrigerant of the refrigerating cycles (RA, RB, RC, RD) and an energization ratio of an intermittent operation period of each of the heating units (21a, 41a, 51a, 71a); and

first controllers (120) each of which is configured to calculate, at the time when each of the compressors (21, 41, 51, 71) is in a stopped state, the temperature difference between the outdoor air temperature measured by the outdoor air temperature measuring unit (150) and the refrigerant saturation temperature at the time of saturation of each refrigerant of the refrigerating cycles (RA, RB, RC, RD) , determine the energization ratio of the intermittent operation period on the basis of this calculation result and the relationship stored in each of the memory units (121), and execute heating control of each of the heating units (21a, 41a, 51a, 71a) according to the determined energization ratio of the intermittent operation,

characterized in that the heat source system further comprises refrigerant temperature measuring units (S1, S2, S3, S4) each of which is configured to measure a refrigerant temperature of the refrigerant discharged from each of the compressors (21, 41, 51, 71), wherein

each of the memory units (121) is configured to further store therein first information indicating a relationship between the temperature of each of the compressors (21, 41, 51, 71) and the refrigerant temperature measured by each of the refrigerant temperature measuring units (S1, S2, S3, S4), and

each of the first controllers (120) is configured to estimate, before the operation of each of the compressors (21, 41, 51, 71), the temperature of each of the compressors (21, 41, 51, 71) from the refrigerant temperature measured by each of the refrigerant temperature measuring units (S1, S2, S3, S4) and the first information, calculate a temperature difference between the estimated temperature and the refrigerant saturation temperature, when the calculated temperature difference becomes less than a set value, start up each of the compressors (21, 41, 51, 71) in a first startup pattern in which a startup securing the reliability of each of the compressors (21, 41, 51, 71) is to be carried out and, when the temperature difference does not become less than the set value, start up each of the compressors (21, 41, 51, 71) in a second startup pattern in which a normal startup is to be carried out.
The heat source system of claim 3, characterized in that
the period is a predetermined time, and

the first controllers (120) are configured to keep heating of the heating units (21a, 41a, 51a, 71a) in an off-state during a first time period within the predetermined time, and keep the heating of the heating units (21a, 41a, 51a, 71a) in an on-state during a second time period after an elapse of the first time period.