US 2022/0090833 A1 · REFRIGERANT CYCLE APPARATUS

Abstract

Excessive specifications of a shutoff valve leads to increase in production cost. An air conditioner configured to circulate a lower flammability refrigerant in a refrigerant circuit includes a first shutoff valve and a second shutoff valve configured to inhibit refrigerant leakage into a predetermined space. Each of the first shutoff valve and the second shutoff valve in a shutoff state has a shutoff leakage rate, as an air leakage rate in a case where fluid is air at 20° C. and a differential pressure between upstream and downstream of the valve is 1 MPa, more than 300 (cm3/min) and less than 300×R (cm3/min). R satisfies R = ( ρ md × V md × A d ) ⁢ / ⁢ ( C r × ( 2 × Δ ⁢ ⁢ P r ⁢ / ⁢ ρ 1 ⁢ rl ) 0.5 × A v × ρ 1 ⁢ rl + A v × ( 2 ⁢ / ⁢ ( λ + 1 ) ) ( ( λ + 1 ) ⁢ / ⁢ 2 ⁢ ( λ - 1 ) ) × ( λ × P 1 ⁢ r × ρ 1 ⁢ rg ) 0.5 ) .

A refrigerant cycle apparatus configured to circulate a lower flammability refrigerant categorized in lower flammability refrigerants by ISO 817 in a refrigerant circuit, the refrigerant cycle apparatus comprising:

a first shutoff valve and a second shutoff valve provided on both sides of a first portion of the refrigerant circuit;
a detector detection unit configured to detect refrigerant leakage from the first portion of the refrigerant circuit into a predetermined space;
and
a controller control unit configured to bring each of the first shutoff valve and the second shutoff valve into a shutoff state when the detector detection unit detects refrigerant leakage into the predetermined space, to inhibit refrigerant leakage into the predetermined space;
wherein
each of the first shutoff valve and the second shutoff valve in the shutoff state has a shutoff leakage rate, as an air leakage rate when fluid is air at 20° C. and a differential pressure between upstream and downstream of the valve is 1 MPa,
more than 300 (cm3/min), and
less than 300×R (cm3/min),
in which
R
=
(
ρ
md
×
V
md
×
A
d
)
⁢
/
⁢
(
C
r
×
(
2
×
Δ
⁢
⁢
P
r
⁢
/
⁢
ρ
1
⁢
rl
)
0.5
×
A
v
×
ρ
1
⁢
rl
+
A
v
×
(
2
⁢
/
⁢
(
λ
+
1
)
)
(
(
λ
+
1
)
⁢
/
⁢
2
⁢
(
λ
-
1
)
)
×
(
λ
×
P
1
⁢
r
×
ρ
1
⁢
rg
)
0.5
)
,
Av is a valve clearance sectional area (m2) of each of the first shutoff valve and the second shutoff valve in the shutoff state,
ρ1rl is a mass concentration (kg/m3) of a refrigerant in a liquid phase,
ρ1rg is a mass concentration (kg/m3) of a refrigerant in a gas phase,
ρ1r is an upstream refrigerant pressure (MPa) of each of the first shutoff valve and the second shutoff valve, as a refrigerant saturation pressure when maximum temperature outside an building is set to 55° C.,
λ is a refrigerant specific heat ratio,
ρmd is a mass concentration (kg/m3) of a gaseous mixture containing air and a refrigerant having reached a refrigerant tolerable average concentration in the predetermined space after refrigerant leakage into the predetermined space and passing a clearance of a door partitioning into inside and outside the predetermined space,
Vmd is a velocity (m/s) of the gaseous mixture containing air and the refrigerant having reached the refrigerant tolerable average concentration in the predetermined space after refrigerant leakage into the predetermined space and passing the clearance of the door partitioning into inside and outside the predetermined space,
Ad is an area (m2) of the clearance of the door partitioning into inside and outside the predetermined space,
ΔPr is a pressure difference (Pa) between inside and outside a hole at a position where the refrigerant leaks, as a differential pressure between the refrigerant saturation pressure when the maximum temperature outside the building is set to 55° C. and an atmospheric pressure, and
Cr is 0.6 as a refrigerant flow rate coefficient in a case where the refrigerant in the liquid phase passes the hole at the position where the refrigerant leaks.

109 more elements

Refrigerant cycle apparatus

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Refrigerant cycle apparatus

Life of this patent

Abstract

Claims5