Air-conditioning apparatus

• US 9,903,601 B2
• Filed: 10/27/2009
• Issued: 02/27/2018
• Est. Priority Date: 10/27/2009
• Status: Active Grant

• Current Assignee: Mitsubishi Electric Corporation
• Original Assignee: Mitsubishi Electric Corporation
• Inventors: Yamashita, Koji, Morimoto, Hiroyuki, Motomura, Yuji
• Primary Examiner(s): Ma, Kun Kai
• Application Number:
  US13/496,824
• Publication Number:
  US 20120174611A1
• Time in Patent Office: 3,045 Days
• Field of Search: 62185, 62201, 622281, 62159, 62200, 62204, 62175
• CPC Class Codes: F24F 11/84 using valves
• CPC Class Codes: F24F 3/065 with a plurality of evaporators or condensers
• CPC Class Codes: F25B 13/00 Compression machines, plants or systems, with reversible cycle defrosting cycles F25B47/02
• CPC Class Codes: F25B 2313/006 two pipes connecting the outdoor side to the indoor side with multiple indoor units
• CPC Class Codes: F25B 2313/0231 with simultaneous cooling and heating
• CPC Class Codes: F25B 2313/0272 using bridge circuits of one-way valves
• CPC Class Codes: F25B 2313/02732 using two three-way valves
• CPC Class Codes: F25B 2313/02741 using one four-way valve
• CPC Class Codes: F25B 2313/0314 Temperature sensors near the indoor heat exchanger
• CPC Class Codes: F25B 25/005 using primary and secondary systems
• CPC Class Codes: F25B 2600/13 Pump speed control
• CPC Class Codes: F25B 2700/21 Temperatures
• CPC Class Codes: F25B 2700/2106 of fresh outdoor air
• CPC Class Codes: Y02B 30/70 Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating

Abstract

To provide an air-conditioning apparatus capable of achieving energy saving, a pump control of controlling the operating capacity of a pump is performed such that an opening degree of a heat medium flow control device, controlled by a heat-medium-flow-control-device control, approaches a target opening degree, and a refrigeration cycle of a refrigerant circuit is controlled such that the temperature of a heat medium, whose flow rate is controlled by the heat-medium-flow-control-device control and the pump control, approaches a target temperature.

Claims

1. An air-conditioning apparatus in which

a compressor, a heat source side heat exchanger, expansion devices, and heat exchangers related to heat medium connect to form a refrigerant circuit for circulating a heat source side refrigerant, and

pumps, a plurality of use side heat exchangers, and the heat exchangers related to heat medium connect to form a plurality of heat medium cycles circulating a heat medium,

the air-conditioning apparatus, comprising:

a plurality of heat medium flow control devices for controlling a flow rate of the heat medium that circulates in each of the use side heat exchangers, respectively;

a first temperature sensor, which is positioned at a point in a passage between each of the heat exchangers related to heat medium and an inlet side of the use side heat exchangers, detecting a temperature of the heat medium;

a second temperature sensor, which is positioned at a point in a passage between each outlet side of the use side heat exchangers and the heat exchangers related to heat medium, detecting a temperature of the heat medium; and

a controller configured to control at least the plurality of heat medium flow control devices, the pumps, the compressor, and the expansion devices,

the controller configured to;

execute a heat medium flow control device control that controls an opening degree of the heat medium flow control devices,

execute a pump control that controls each operation capacity of the pumps, based upon a relationship of a maximum opening degree among the plurality of heat medium flow control devices to a predetermined target opening degree, and

execute a refrigeration-cycle control of the refrigerant circuit such that the detection temperature of the first temperature sensor approaches a target temperature of the heat medium, whose wherein the flow rate is controlled by the heat medium flow control device control and the pump control, by setting a control target value of at least one of a condensing temperature and an evaporating temperature of the heat source side refrigerant, or a control target value of at least one of an amount of change of the condensing temperature and an amount of change of the evaporating temperature of the heat source side refrigerant based on the detection temperature of the heat medium by the first temperature sensor.

2. The air-conditioning apparatus of claim 1, wherein

a control interval of the pump control is longer than a control interval of the heat medium flow control device control, and

a control interval of the refrigeration-cycle control is longer than the control interval of the pump control.

3. The air-conditioning apparatus of claim 1, wherein

a control interval of the pump control is 3 times or more longer than a control interval of the heat medium flow control device control, and

a control interval of the refrigeration-cycle control is 3 times or more longer than the control interval of the pump control.

4. The air-conditioning apparatus of claim 1, wherein

the controller is configured to control the opening degree of each of the heat medium flow control devices based on a difference between a detection temperature difference between the first temperature sensor and the second temperature sensor and a target temperature difference of each of the use side heat exchangers to the target temperature thereof so as to control the flow rate of the heat medium circulating in the use side heat exchanger.

5. The air-conditioning apparatus of claim 4, wherein

the controller is configured to set a control gain of each of the heat medium flow control devices based on a difference between an opening area at a current opening degree of the heat medium flow control devices or a value corresponding to the opening area and an opening area predicted value of the heat medium flow control devices or a predicted value of the value corresponding to the opening area at the time when the detection temperature difference becomes the target temperature difference.

6. The air-conditioning apparatus of claim 5, wherein

the controller is configured to obtain the opening area predicted value or the predicted value of the value corresponding to the opening area based on the detection temperature difference, the target temperature difference, and the opening area at the current opening degree or the value corresponding the opening area.

7. The air-conditioning apparatus of claim 5, wherein

the controller is configured to change the control gain of the heat medium flow control device continuously or in steps.

8. The air-conditioning apparatus of claim 1, wherein

the controller is configured to control operating capacities of the pumps such that the opening degree or a value corresponding to the opening degree of the heat medium flow control devices approaches a target opening degree based on the opening degree or the value corresponding to the opening degree of the heat medium flow control devices that is controlled by the heat medium flow control device control.

9. The air-conditioning apparatus of claim 8, wherein

the target opening degree is set in advance based on an opening degree or the value corresponding to the opening degree, which are corresponding to the maximum opening degree of the heat medium flow control device, and

the operating capacities of the pumps are controlled such that the maximum value or the mean value of the opening degree or the value corresponding to the opening degree of the heat medium flow control devices approaches the target opening degree or the value corresponding to the opening degree.

10. The air-conditioning apparatus of claim 8, wherein

the air-conditioning apparatus is capable of carrying out:

a heating only operation mode that heats the heat medium by allowing a high-temperature high-pressure heat source side refrigerant discharged from the compressor to flow through all of the heat exchangers related to heat medium;

a cooling only operation mode that cools the heat medium by allowing a low-temperature low-pressure heat source side refrigerant discharged from the compressor to flow through all of the heat exchangers related to heat medium; and

a cooling and heating mixed operation mode that heats the heat medium by allowing the high-temperature high-pressure heat source side refrigerant discharged from the compressor to flow through one or some of the heat exchangers related to heat medium, and cools the heat medium by allowing a low-temperature low-pressure heat source side refrigerant to flow through one or some of the other heat exchangers related to heat medium,

in the cooling and heating mixed operation mode

the pumps are separated into a heating side pump corresponding to the heat exchanger related to heat medium that heats the heat medium and a cooling side pump corresponding to the heat exchanger related to heat medium that cools the heat medium,

the operating capacity of the heating side pump is controlled such that the maximum value or the mean value of the opening degree or the value corresponding to the opening degree of the heat medium flow control devices corresponding to the use side heat exchanger in heating operation approaches the target opening degree, and

the operating capacity of the cooling side pump is controlled such that the maximum value or the mean value of the opening degree or the value corresponding to the opening degree of the heat medium flow control devices corresponding to the use side heat exchanger in cooling operation approaches the target opening degree.

11. The air-conditioning apparatus of claim 8, wherein the controller

has a capacity code, which is information on the amount of each heat exchange of the use side heat exchangers, set in advance,

changes the operating capacity of the heating side pump based on the total value of the capacity codes of the use side heat exchangers that are in heating operation, and

changes the operating capacity of the cooling side pump based on the total value of the capacity codes of the use side heat exchangers that are in cooling operation.

12. The air-conditioning apparatus of claim 1, further comprising

an outdoor air temperature sensor that detects a suction temperature of air that is to exchange heat with the heat source side refrigerant being provided in the heat source side heat exchanger, wherein

the target temperature of the heat medium is changed based on the detection temperature of the outdoor air temperature sensor.

13. The air-conditioning apparatus of claim 1, further comprising

an indoor air temperature sensor that detects a suction temperature of air that is to exchange heat with the heat medium, being provided in each of the use side heat exchangers, wherein

the target temperature of the heat medium is changed based on the difference between the detection temperature of the indoor air temperature sensor and a target temperature of the conditioned space.

14. The air-conditioning apparatus of claim 1, wherein

the compressor and the heat source side heat exchanger are housed in an outdoor unit,

the expansion devices, the heat exchangers related to heat medium, and the pumps are housed in a heat medium relay unit,

each use side heat exchanger is housed in an indoor unit, and

the outdoor unit, the heat medium relay unit, and the indoor unit are constitutable in separate housings and are installable at separate places.

15. The air-conditioning apparatus of claim 1, wherein

the compressor and the heat source side heat exchanger are housed in an outdoor unit, the expansion devices,

the heat exchangers related to heat medium, and the pumps are housed in a heat medium relay unit,

the outdoor unit and the heat medium relay unit are constitutable in separate housings and are installable at separate places,

the controller includes:

a first control unit that is configured to control at least the heat medium flow control device, the pumps, and the expansion devices, the first control unit being disposed inside or at a position near the heat medium relay unit; and

a second control unit that is configured to control at least the heat source side heat exchanger, the second control unit being disposed inside or at a position near the outdoor unit, the air-conditioning apparatus wherein

the first control unit and the second control unit are connected with each other by wireless or wire, and

the first control unit transmits the control target value, which is either or both of the condensing temperature and the evaporating temperature of the heat source side refrigerant or the control target value, which is either or both of amount of change of the condensing temperature and an amount of change of the evaporating temperature, to the second control unit as a control signal.

16. The air-conditioning apparatus of claim 1, wherein

the heat medium flow control device is housed in a heat medium relay unit.

17. The air-conditioning apparatus of claim 1, wherein

the expansion devices, the heat exchangers related to heat medium, and the pumps are housed in a heat medium relay unit,

the heat medium flow control devices are disposed in separate housing to the housing of the heat medium relay unit,

the controller further includes:

a first control unit that is configured to control the heat medium flow control devices, the pumps, and the expansion devices, the first control unit being disposed inside or at a position neat the heat medium relay unit; and

a third control unit disposed inside or at a position near a housing separate to the housing of the heat medium relay unit, wherein

the first control unit and the third control unit are connected with each other by wireless or wire, and

the third control unit transmits information, which is the opening degree or the opening area of the heat medium flow control devices, to the first control unit.

18. The air-conditioning apparatus of claim 1, wherein

the first temperature sensor and the second temperature sensor are housed in a heat medium relay unit.