Air-conditioning apparatus with safety measure for ventilation of inflammable refrigerant from heat exchanger

Patent metadata

Field	Value
Publication number	US-9459013-B2
Application number	US-201013878262-A
Country	US
Kind code	B2
Filing date	Dec 3, 2010
Priority date	Dec 3, 2010
Publication date	Oct 4, 2016
Grant date	Oct 4, 2016

Abstract

A refrigerant circuit device includes a compressor, a heat exchanger that is capable of exchanging heat between the refrigerant and a heat medium, and other components that are connected by pipes, in which the refrigerant circuit circulates a refrigerant. A heat medium circulating circuit circulates the heat medium in the heat exchanger. At least the compressor is housed in an outdoor unit, at least the heat exchanger is housed in a heat medium relay unit, and an indoor unit is housed in a use side heat exchanger. The outdoor unit, the heat medium relay unit, and the indoor unit are formed separately and can be disposed in separate positions. A housing of the heat medium relay unit has an opening that allows ventilation between the housing space of the heat exchanger related to heat medium and the space outside the housing space.

First claim

The invention claimed is:

1. An air-conditioning apparatus, comprising:
a refrigeration cycle including a refrigerant circuit for circulating a refrigerant, the refrigerant circuit being constituted by connecting with pipes a compressor that sends out a combustible refrigerant, a refrigerant flow switching device configured to switch circulation paths of the refrigerant, a heat source side heat exchanger configured to exchange heat of the refrigerant, a refrigerant expansion device configured to control a pressure of the refrigerant, and a plurality of heat exchangers related to heat medium capable of exchanging heat between the refrigerant and a heat medium that is different from the refrigerant; and
a heat medium side circuit constituted by a heat medium circulating circuit that is constructed by connecting a plurality of heat medium sending devices configured to circulate the heat medium pertaining to heat exchange of the heat exchangers related to heat medium, and a plurality of use side heat exchangers exchanging heat between the heat medium and air related to a space to be air-conditioned, with pipes, wherein
at least the compressor, the refrigerant flow switching device, the heat source side heat exchanger are housed in an outdoor unit, at least the heat exchangers related to heat medium and the refrigerant expansion device are housed in a heat medium relay unit, and the use side heat exchangers are housed in corresponding indoor units, each of the outdoor unit, the heat medium relay unit, and the indoor units being separately formed and being allowed to be disposed at separate positions,
a housing of the heat medium relay unit includes an opening allowing ventilation between an inside of the housing and an outside of the housing, and a relay-unit air-sending device that sends air,
a controller configured to perform a control operation of the relay-unit air-sending device such that refrigerant concentration inside the housing of the heat medium relay unit is maintained under a predetermined concentration, the controller is configured to
set, in the control operation, a ventilation volume of the relay-unit air-sending device to 0.55×m (m 3 /min) or greater with respect to a refrigerant amount m (kg) in the refrigerant circuit, and

the heat medium circulating circuit includes heat medium flow switching devices being connected by pipes to the corresponding use side heat exchangers to perform switching such that the heat medium that passes through each of the heat exchangers related to heat medium is selected and is caused to flow into the use side heat exchangers.

2. The air-conditioning apparatus of claim 1 , wherein a total area of the opening is 10% or larger than a surface area of the housing of the heat medium relay unit, the surface area including the total area of the opening.

3. The air-conditioning apparatus of claim 1 , wherein the controller operates the relay-unit air-sending device in order to maintain the refrigerant concentration under the predetermined concentration even when the compressor of the outdoor unit is in a suspended state.

4. The air-conditioning apparatus of claim 1 , further comprising:
a refrigerant concentration detection device that detects the refrigerant concentration inside the housing, wherein
the controller operates the relay-unit air-sending device on a basis of a detection value of the refrigerant concentration detection device.

5. The air-conditioning apparatus of claim 4 , further comprising:
shut-off devices that shut off a flow of the refrigerant, the shut-off devices each being disposed in a refrigerant inlet/outlet of the heat medium relay unit, wherein
the controller makes the shut-off devices shut off the flow of the refrigerant on a basis of the detection value of the refrigerant concentration detection device.

6. The air-conditioning apparatus of claim 1 , wherein the refrigerant is R32 and the ventilation volume of the relay-unit air-sending device is set to 0.784×m (m 3 /min) or greater.

7. The air-conditioning apparatus of claim 1 , wherein the refrigerant is HFO1234yf and a ventilation volume Q of the relay-unit air-sending device is set to 0.830×m (m 3 /min) or greater.

8. The air-conditioning apparatus of claim 1 , wherein the refrigerant is a mixed refrigerant of at least HFO1234yf and R32 and the ventilation volume of the relay-unit air-sending device is set to (0.784×ratio of R32+0.830×ratio of HFO1234yf)×m (m 3 /min) or greater.

9. The air-conditioning apparatus of claim 1 , wherein the refrigerant is propane and the ventilation volume of the relay-unit air-sending device is set to 6.3×m (m 3 /min) or greater.

10. The air-conditioning apparatus of claim 1 , wherein the refrigerant amount m (kg) in the heat medium relay unit is a maximum refrigerant amount allowed to exist in the heat medium relay unit on the basis of a refrigerant state according to an operation mode carried out by the heat medium circulating circuit.

11. The air-conditioning apparatus of claim 1 , wherein the refrigerant amount m (kg) in the heat medium relay unit is a product of a total value (m 3 ) of internal volumes of refrigerant pipes and components in which the refrigerant passes in the heat medium relay unit, and a density (kg/m 3 ) of the refrigerant.

12. The air-conditioning apparatus of claim 1 , wherein the refrigerant amount m (kg) in the heat medium relay unit is a product of a total value (m 3 ) of the internal volumes of refrigerant pipes and components in which the refrigerant passes in the heat medium relay unit, and 1000 (kg/m 3 ).

13. The air-conditioning apparatus of claim 1 , wherein the heat medium flow switching devices are housed in the heat medium relay unit.

14. The air-conditioning apparatus of claim 1 , wherein the heat medium circulating circuit includes a heat medium flow control device that is connected by pipes and that controls a flow rate of the heat medium caused to flow into and out of the use side heat exchanger, the heat medium flow control device being housed in the heat medium relay unit.

15. The air-conditioning apparatus of claim 1 , wherein the outdoor unit and the heat medium relay unit are connected by two pipes, and the heat medium relay unit and each of the indoor units are connected by two pipes.

16. The air-conditioning apparatus of claim 1 , wherein the heat medium relay unit is disposed in a space inside a structure in which ventilation to an outdoor space by natural convection or forced convection is allowed.

17. The air-conditioning apparatus of claim 1 , wherein
the controller is configured to set, in the control operation, a ventilation volume of the relay-unit air-sending device to between 0.55 to 6.3×m (m 3 /min) with respect to the refrigerant amount m (kg) in the refrigerant circuit.

Assignees

• Yamashita Koji
• Morimoto Hiroyuki
• Mitsubishi Electric Corp

Inventors

• Yamashita Koji
• Morimoto Hiroyuki

Classifications

• F24F11/74

  for controlling air flow rate or air velocity · CPC title

• F24F3/065 Primary

  with a plurality of evaporators or condensers · CPC title

• F24F1/32 Primary

  for connecting the separate outdoor units to indoor units · CPC title

• F24F13/20

  Casings or covers · CPC title

• F25B2313/0233

  in parallel arrangements · CPC title