# US 11,441,813 B2 · Indoor unit of refrigeration apparatus

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- Number: US 11,441,813 B2
- Document ID: US11441813B2
- Status: Granted
- Kind: B2
- Application number: 17/572,890
- Filed: 2022-01-11
- Published: 2022-04-28
- Granted: 2022-09-13
- Earliest claimed: 2019-07-12
- Assignees: Daikin Industries, Ltd.
- Applicants: Daikin Industries, Ltd.
- Inventors: Yoshiyuki Tsuji; Makoto Kojima
- Web page: https://patentgrep.com/patent/US11441813B2

## CPC

- F24F 13/222: {for evacuating condensate}
- F25B 49/02: for compression type machines, plants or systems
- F24F 1/0043: characterised by mounting arrangements
- F24F 1/0063: by the mounting or arrangement of the heat exchangers
- F24F 11/36: to leakage of heat-exchange fluid
- F24F 11/89: Arrangement or mounting of control or safety devices
- F24F 13/20: Casings or covers
- F25B 13/00: Compression machines, plants or systems, with reversible cycle (defrosting cycles F25B47/02)
- F25B 49/005: {of safety devices (F25B49/02 and F25B49/04 take precedence)}
- F24F 2110/66: Volatile organic compounds [VOC]
- F25B 2500/222: Detecting refrigerant leaks
- F24F: AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING (removing dirt or fumes from areas where they are produced B08B15/00; vertical ducts for carrying away waste gases from buildings E04F17/02; tops for chimneys or ventilating shafts, terminals for flues F23L17/02)
- F25B: REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS

## Abstract

An indoor unit of a refrigeration apparatus includes: a drain pan that includes four wall surfaces including a first wall surface, and has a quadrangle shape in a plan view; a heat exchanger disposed above the drain pan and through which a combustible refrigerant, having a larger specific gravity than air, flows; a fan that generates air flow to the heat exchanger; a gas sensor that detects a refrigerant leakage; and a casing accommodating the drain pan, the heat exchanger, the fan, and the gas sensor.

## Claims

### Claim 1

An indoor unit of a refrigeration apparatus comprising:
a drain pan that:
comprises four wall surfaces including a first wall surface, and
has a quadrangle shape in a plan view;
a heat exchanger disposed above the drain pan and through which a combustible refrigerant, having a larger specific gravity than air, flows;
a fan that generates air flow to the heat exchanger;
a gas sensor that detects refrigerant leakage; and
a casing accommodating the drain pan, the heat exchanger, the fan, and the gas sensor, wherein
the casing comprises:
side plates, including a first side plate, that constitute side surfaces of an outer contour of the casing;
a partition plate that divides an internal space surrounded by the side plates into a first chamber in which the drain pan is disposed and a second chamber in which the fan is disposed; and
a blow-out port disposed in the first side plate,
the first side plate faces the first wall surface of the drain pan,
the wall surfaces of the drain pan other than the first wall surface are arranged along the side plates or the partition plate, and
the gas sensor is disposed above the drain pan and satisfies
L·W{C1·H1/Q+C2·H/(Q−C3·L·H{circumflex over ( )}(3/2))}≤90,
where
C1=0.0067,
C2=0.01172,
C3=0.000153,
H is a height of the gas sensor from an upper end of the drain pan in [m],
L is a length of the first wall surface of the drain pan in [m],
W is a length of a wall surface of the drain pan intersecting with the first wall surface in [m],
H1 is a depth of the drain pan in [m], and
Q is a refrigerant leakage flow rate in [m3/s].

### Claim 2 (depends on 1)

The indoor unit according to claim 1, wherein
the indoor unit further comprises a control board,
the heat exchanger comprises a first end and a second end,
the first end is closer to the control board than the second end is, and
the gas sensor is disposed closer to the first end than to the second end.

### Claim 3 (depends on 2)

The indoor unit according to claim 2, wherein
the heat exchanger comprises:
heat transfer tubes;
a collection tube connected to a first end of each of the heat transfer tubes; and
a connection tube connected to a second end of each of the heat transfer tubes, and
the control board is installed closer to the collection tube than to the connection tube.

### Claim 4 (depends on 2)

The indoor unit according to claim 2, wherein the control board is disposed along one of the side plates or the partition plate.

### Claim 5 (depends on 1)

The indoor unit according to claim 1, wherein
the casing further comprises:
an opening in one of the side plates; and
a lid that closes the opening, and
the gas sensor is disposed at a position that is attachable and detachable through the opening when the lid is opened.

### Claim 6 (depends on 1)

The indoor unit according to claim 1, wherein the gas sensor is disposed below the heat exchanger.

### Claim 7 (depends on 1)

The indoor unit according to claim 1, wherein
the indoor unit further comprises a plurality of gas sensors that each detects refrigerant leakage, and
the plurality of gas sensors are installed at different locations.

### Claim 8 (depends on 1)

The indoor unit according to claim 1, wherein the gas sensor is covered by a case having an opening for ventilation.

### Claim 9 (depends on 1)

The indoor unit according to claim 1, wherein
the gas sensor comprises a detector and a wire, and
the wire is disposed below the detector.