Air-conditioning apparatus

Patent metadata

Field	Value
Publication number	US-9933205-B2
Application number	US-201114111795-A
Country	US
Kind code	B2
Filing date	May 23, 2011
Priority date	May 23, 2011
Publication date	Apr 3, 2018
Grant date	Apr 3, 2018

Abstract

An outdoor unit is configured to include a compressor and a heat source side heat exchanger. Indoor units are configured to include first expansion devices and use side heat exchangers, and air-condition an air-conditioned space. Branching devices, connected by pipes to the outdoor unit by a plurality of main pipes and connected by pipes to each indoor unit by a plurality of branch pipes, are configured to branch a refrigerant from a side of the main pipes and circulate the refrigerant to the branch pipes, and converge the refrigerant from a side of the branch pipes and circulate the refrigerant to the main pipes. A refrigerant concentration detecting device is installed in a non-air-conditioned space. A shutoff valve control device is configured, upon determining that the refrigerant has leaked, to control shutoff devices and to shut off the refrigerant flows.

First claim

The invention claimed is:

1. An air-conditioning apparatus comprising:
an outdoor unit configured to include a compressor and a heat source side heat exchanger;
a plurality of indoor units configured to include load-side expansion valves and load-side heat exchangers and configured to air-condition an air-conditioned space;
branching pipes, connected to the outdoor unit by a plurality of main pipes and connected to each indoor unit by a plurality of branch pipes, configured to branch a refrigerant from a side of the main pipes and circulate the refrigerant to the branch pipes, and converge the refrigerant from a side of the branch pipes and circulate the refrigerant to the main pipes;
a refrigerant concentration detecting device installed in a non-air-conditioned space, which is a different space from the air-conditioned space, and which is in a relative position where the refrigerant potentially spread into the air-conditioned space if the refrigerant leaks;
shutoff valves configured to shut off either or both flows between the outdoor unit and the branching pipes on the side of the main pipes and flows between the indoor units and the branching pipes on the side of the branch pipes; and
a controller configured, upon determining that the refrigerant has leaked on a basis of a detection by the refrigerant concentration detecting device, to control the shutoff valves to shut off the refrigerant flows; wherein
the branching pipes are installed in the non-air-conditioned space, and
provided that a refrigerant quantity inside the main pipes is a main-pipe enclosed refrigerant quantity W1 (kg), a refrigerant quantity inside the branch pipes is a branch-pipe enclosed refrigerant quantity W2 (kg), a refrigerant quantity inside the outdoor unit is M1 (kg), and a refrigerant quantity inside the indoor units is M2 (kg),
one of either
a value (W1+M1)/V obtained by dividing a sum of the main-pipe enclosed refrigerant quantity W1 and the refrigerant quantity M1 inside the outdoor unit by a volume V (m 3 ) of the air-conditioned space or
a value (W2+M2)/V obtained by dividing a sum of the branch-pipe enclosed refrigerant quantity W2 and the refrigerant quantity M2 inside the indoor units by the volume V (m 3 ) of the air-conditioned space

is equal to or greater than a predetermined refrigerant charged quantity limit value B (kg/m 3 ) determined on a basis of a flammability risk of the refrigerant, wherein the shutoff valves shut off pipes on a side equal to or greater than the predetermined refrigerant charged quantity limit value B (kg/m 3 ).

2. The air-conditioning apparatus of claim 1 , wherein
when the value (W1+M1)/V and the value (W2+M2)/V do not satisfy the predetermined refrigerant charged quantity limit value B (kg/m 3 ), and a sum of the value (W1+M1)/V and the value (W2+M2)/V is equal to or greater than the predetermined refrigerant charged quantity limit value B (kg/m 3 ), the shutoff valves are provided on either the side of the main pipes or the side of the branch pipes.

3. The air-conditioning apparatus of claim 1 , wherein
the shutoff valves are further provided at a position in the vicinity of the indoor units, and
the refrigerant quantity M2 inside the indoor units is set to 0 kg.

4. The air-conditioning apparatus of claim 1 , wherein
a length of the main pipes between the shutoff valves on the side of the main pipes and the branching pipes is set such that a value W3/V obtained by dividing a refrigerant quantity W3 (kg) in the main pipes between the shutoff valves on the side of the main pipes and the branching pipes by the volume V (m 3 ) of the air-conditioned space is less than or equal to the predetermined refrigerant charged quantity limit value B (kg/m 3 ), and
a length of the branch pipes between the shutoff valves on the side of the branch pipes and the branching pipes is set such that a value W4/V obtained by dividing a refrigerant quantity W4 (kg) in the branch pipes between the shutoff valves on the side of the branch pipes and the branching pipes by the volume V (m 3 ) of the air-conditioned space is less than or equal to the predetermined refrigerant charged quantity limit value B (kg/m 3 ).

5. The air-conditioning apparatus of claim 1 , wherein a length of the main pipes between the shutoff valves on the side of the main pipes and the branching pipes is set such that a value (W3+W2+M2)/V obtained by dividing a sum of a refrigerant quantity W3 (kg) in the main pipes between the shutoff valves on the side of the main pipes and the branching pipes, a branch pipe enclosed refrigerant quantity W2 (kg), and a refrigerant quantity M2 (kg) inside the indoor units by the volume V (m 3 ) of the air-conditioned space is less than or equal to the predetermined refrigerant charged quantity limit value B (kg/m 3 ).

6. The air-conditioning apparatus of claim 1 , wherein a length of the branch pipes between the shutoff valves on the side of the branch pipes and the branching pipes is set such that a value (W4+W1+M1)/V obtained by dividing a sum of a refrigerant quantity W4 (kg) in the branch pipes between the shutoff valves on the side of the branch pipes and the branching pipes, a main-pipe enclosed refrigerant quantity W1 (kg), and the refrigerant quantity M1 (kg) inside the outdoor unit by the volume V (m 3 ) of the air-conditioned space is less than or equal to the predetermined refrigerant charged quantity limit value B (kg/m 3 ).

7. The air-conditioning apparatus of claim 1 , wherein the refrigerant is a refrigerant with flammable properties.

8. The air-conditioning apparatus of claim 7 , wherein the refrigerant is HFO-1234yf, HFO-1234ze, R32, a refrigerant mixture containing R32 and HFO-1234yf, a refrigerant mixture containing at least one of HFO-1234yf, HFO-1234ze, or R32 as a component, or HC.

9. The air-conditioning apparatus of claim 8 , wherein the refrigerant charged quantity limit value B is 0.800 kg/m 3 or less for R32, 0.759 kg/m 3 or less for HFO-1234yf, 0.777 kg/m 3 or less for a refrigerant mixture with a composition ratio of 44% for R32 and 56% for HFO-1234yf, 0.790 kg/m 3 or less for a refrigerant mixture with a composition ratio of 73% for R32 and 27% for HFO-1234yf, and 0.105 kg/m 3 or less for propane.

10. The air-conditioning apparatus of claim 1 , wherein the refrigerant circuit encloses 20 kg or greater in the case where the refrigerant is R32, 19.43 kg or greater in the case where the refrigerant is the refrigerant mixture with the composition ratio of 44% for R32 and 56% for HFO-1234yf, 19.75 kg or greater in the case where the refrigerant is the refrigerant mixture with the composition ratio of 73% for R32 and 27% for HFO-1234yf, 18.98 kg or greater in the case where the refrigerant is HFO-1234yf, and 2.63 kg or greater in the case where the refrigerant is propane.

11. The air-conditioning apparatus of claim 1 , wherein a detector of the refrigerant concentration detecting device is made of materials including tin oxide.

12. The air-conditioning apparatus of claim 2 wherein
the branching pipes form a relay unit that includes a gas liquid separator and opening and closing devices that supply the gas refrigerant to indoor units performing heating among the indoor units, and supply the liquid refrigerant to indoor units performing cooling among the indoor units, and
provided that a refrigerant quantity inside the relay unit is M3 (kg), a value (W2+M2+M3)/V obtained by dividing the sum of the branch-pipe enclosed refrigerant quantity W2, the refrigerant quantity M2 inside the indoor units, and the refrigerant quantity M3 inside the relay unit by the volume V of the air-conditioned space is used instead of the value (W2+M2)/V.

Assignees

• Hatomura Takeshi
• Yamashita Koji
• Morimoto Hiroyuki
• Mitsubishi Electric Corp

Inventors

• Hatomura Takeshi
• Yamashita Koji
• Morimoto Hiroyuki

Classifications

• F25B49/005

  of safety devices (F25B49/02 and F25B49/04 take precedence) · CPC title

• F25B2313/02741

  using one four-way valve · CPC title

• F25B2500/22

  Preventing, detecting or repairing leaks of refrigeration fluids · CPC title

• F25D29/006 Primary

  Safety devices · CPC title

• F24F2011/0052

  Mechanical Engineering · mapped topic