AIR-CONDITIONING APPARATUS

• US 20120304675A1
• Filed: 02/10/2010
• Published: 12/06/2012
• Est. Priority Date: 02/10/2010
• Status: Active Grant

• Current Assignee: Mitsubishi Electric Corporation
• Original Assignee: Mitsubishi Electric Corporation
• Inventors: Motomura, Yuji, Yamashita, Koji, Morimoto, Hiroyuki, Ue, Jyunichi
• Granted Patent: US 9,353,958 B2
• Time in Patent Office: Days
• US Class Current: 62/156
• CPC Class Codes: F24F 11/41 Defrosting; Preventing freezing
• CPC Class Codes: F24F 11/89 Arrangement or mounting of control or safety devices
• CPC Class Codes: F24F 2221/54 Heating and cooling, simultaneously or alternatively
• CPC Class Codes: F24F 3/06 characterised by the arrangements for the supply of heat-exchange fluid for the subsequent treatment of primary air in the room units
• CPC Class Codes: F25B 13/00 Compression machines, plants or systems, with reversible cycle defrosting cycles F25B47/02
• CPC Class Codes: F25B 2313/0231 with simultaneous cooling and heating
• CPC Class Codes: F25B 2313/02322 during defrosting
• 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 25/005 using primary and secondary systems
• CPC Class Codes: F25B 2600/2513 Expansion valves
• CPC Class Codes: F25B 47/025 by reversing the cycle

Abstract

To obtain an air-conditioning apparatus that is capable of performing an effective defrosting operation, as well as saving energy, the air-conditioning apparatus has a heating operation mode that heats a heat medium in at least one of the heat exchangers related to heat medium, a heat recovery defrosting operation mode that melts frost attached to a heat source side heat exchanger—during the heating operation mode by operating at least one of the pumps and by making a heat source side refrigerant receive heat from the heat medium that is flowing in the at least one of the heat exchangers related to heat medium, and a bypass defrosting operation mode that melts frost attached to the heat source side heat exchanger during the heating operation mode by passing a portion or all of the heat source side refrigerant through a bypass piping.

Claims

1. An air-conditioning apparatus, comprising:

a refrigerant circuit including at least a compressor, a heat source side heat exchanger, an expansion device, and a refrigerant side passage of a heat exchanger related to heat medium connected by piping in series, the refrigerant circuit circulating a heat source side refrigerant; and

a heat medium circuit including at least a heat medium side passage of the heat exchanger related to heat medium, a pump, and a use side heat exchanger connected by piping in series, the heat medium circuit circulating a heat medium, wherein

at least two or more pumps and at least two or more heat exchangers related to heat medium are provided

at least a bypass piping is provided in the refrigerant circuit, bypasses the heat exchanger related to heat medium and returns the heat source side refrigerant to the compressor,

the air-conditioning apparatus has;

a heating operation mode in which after the refrigerant discharged from the compressor has flowed into at least one of the heat exchangers related to heat medium and has exchanged heat with the heat medium, the refrigerant receives heat in the heat source side heat exchanger and the heat medium that has been heated in the heat exchanger(s) related to heat medium flows into a used side heat exchanger having a heating requirement and transfers heat;

a first defrosting operation mode that is switched from the heating operation mode when an evaporating temperature in the heat source side heat exchanger becomes equal to or lower than a predetermined temperature, in which after the refrigerant discharged from the compressor has transferred heat in the heat source side heat exchanger, the refrigerant flows into the at least one of the heat exchangers related to heat medium that had heated the heat medium during the heating operation, receives heat from the heat medium, and is sucked into the compressor, and the heat medium that had been cooled in the heat exchanger related to heat medium flows into a use side heat exchanger having a heating requirement; and

a second defrosting operation mode that is switched from the first defrosting operation mode when a heat medium temperature flowing into the use side heat exchanger having the heating requirement is equal to or lower than a predetermined temperature, in which after the refrigerant discharged from the compressor transfers heat in the heat source side heat exchanger, the refrigerant bypasses the heat exchanger(s) related to heat medium that is conveying the heat medium to the use side heat exchanger having a heating requirement and is sucked into the compressor.

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

whether to carry out the first defrosting operation mode or the second defrosting operation mode is determined based on a heat medium temperature in an outlet of the heat exchanger related to heat medium.

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

the first defrosting operation mode is carried out when the heat medium temperature in the outlet of the heat exchanger related to heat medium is equal to or higher than a first set temperature and

the second defrosting operation mode is carried out when the heat medium temperature in the outlet of the heat exchanger related to heat medium is lower than the first set temperature.

5. The air-conditioning apparatus of claim 4, wherein the first set temperature is a temperature of a use side medium supplied to the use side heat exchanger.

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

the compressor reduces a rotation speed or the second defrosting operation mode is carried out when the refrigerant temperature of any portion in the passage between the expansion device to the outlet side of the heat exchanger related to heat medium is lower than a second set temperature or when estimated to be lower.

7. The air-conditioning apparatus of claim 1, wherein in the first defrosting operation mode carried out during a heating only operation mode, which is a mode among the heating operation mode, in which all of the heat exchangers related to heat medium heat the heat medium,

frost attached to the heat source side heat exchanger is melted by virtually fully opening the expansion device and by having the heat source side refrigerant receive heat from the heat medium flowing in all of the heat exchangers related to heat medium.

8. The air-conditioning apparatus of claim 7, wherein the second defrosting operation mode is carried out by totally closing the expansion device and passing the entire heat source side refrigerant that is flowing in all of the heat exchangers related to heat medium through the bypass piping.

9. The air-conditioning apparatus of claim 1, wherein in the first defrosting operation mode carried out during a heating main operation mode, which is a mode among the heating operation mode, in which one or some of the heat exchangers related to heat medium heat the heat medium and one or some of the remaining heat exchangers related to heat medium cool the heat medium,

frost attached to the heat source side heat exchanger is melted by virtually fully opening the expansion device corresponding to the heat exchanger related to heat medium that had heated the heat medium, by continuing the cooling in the heat exchanger related to heat medium that had been cooling the heat medium, and by having the heat source side refrigerant receive heat from the heat medium flowing in the heat exchanger related to heat medium that had heated the heat medium.

10. The air-conditioning apparatus of claim 9, wherein the bypass second defrosting operation mode is carried out by totally closing the expansion device corresponding to the heat exchanger related to heat medium that had heated the heat medium, by continuing the cooling in the heat exchanger related to heat medium that had been cooling the heat medium, and by passing a portion of the heat source side refrigerant through the bypass piping.

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

in the first defrosting operation mode

supplying of the use side medium to the use side heat exchanger that had been carrying out heating operation is stopped and the supplying of the use side medium to the use side heat exchanger that is carrying out cooling operation is continued.

12. The air-conditioning apparatus of claim 1, wherein a housing accommodating the compressor and the outdoor heat exchanger;

a housing accommodating the heat exchanger related to heat medium, the expansion device, and the pump; and

a housing accommodating the use side heat exchanger are each a different housing.

2. (canceled)