An air conditioner for a vehicle includes a refrigeration cycle, a heating unit and a control unit. The refrigeration cycle includes an air-conditioning evaporator, a chilling evaporator, an air-conditioning side flow path, a detour flow path and an air-conditioning flow rate adjustment unit. The control unit includes a determination unit that determines whether a condensation condition is satisfied when a refrigerant is flowing through the chilling evaporator via the detour flow path in a state where an inflow of a refrigerant into the air-conditioning evaporator is prohibited. When the determination unit determines that the condensation condition is satisfied, the control unit controls the air-conditioning flow rate adjustment unit to allow an inflow of a refrigerant into the air-conditioning evaporator as a condensation suppression operation for suppressing condensation of a refrigerant in the air-conditioning evaporator.

The invention relates to a thermoplastic composition for a monolayer tube (T1, T2), and particularly to an air-conditioning circuit for a motor vehicle comprising tubes transporting a refrigerating fluid.

The composition comprises in weight fractions: more than 20% and up to 40% of a PA 6.10 and/or a PA 6.12, from 45% to less than 60% of a polyphthalamide having a Tg higher than 120° C. and selected from PA 6.I/6.T, PA 9.T, PA 10.T, PA 10.T/X, and from 10% to 20% of a compatibilizing system comprising a reaction product between (a) a polymer of olefin comprising an unsaturated epoxide and (b) a polymer of olefin comprising an unsaturated carboxylic acid, with weight ratio (a):(b) greater than 1.

An HVAC system includes a high-pressure subsystem and a low-pressure subsystem. After determining that refrigerant leak diagnostics should be performed, a controllable valve is closed between a condenser and compressor of the HVAC system. The compressor then operates until a predetermined input refrigerant pressure is reached. After the predetermined input refrigerant pressure is reached, operation of the compressor is stopped. After stopping operation of the compressor and waiting at least a predetermined wait time, the pressure in the low-pressure subsystem of the HVAC system is monitored. A rate of change of the pressure in the low-pressure subsystem is determined. If the rate of change is negative and a magnitude of the rate of change is greater than a threshold value, a leak location is determined to be in the low-pressure subsystem.

A refrigeration system, comprising an evaporator, a condenser, a throttling device, a compressor, an economizer and an ejector, these devices together form a closed-loop refrigerant circulation loop, the ejector being connected to the economizer, and the ejector being provided on an exhaust side of the compressor. The structure enables the refrigeration system to realize the dual-stage boost, does not affect the stability of the compressor due to the instability of the airflow of the ejector, and does not affect the oil property of the compressor, thereby ensuring the operation safety of the compressor.

There is provided a HVAC system comprising: a fluid circuit for conveying a refrigerant; a compressor for compressing the refrigerant; three heat exchangers defining an evaporator, an outdoor exchanger and a heat recovery exchanger provided along the fluid circuit; an expansion valve provided along the fluid circuit; and a receiver connected in parallel to the expansion valve, wherein a fill valve is located between the receiver and a connection upstream of the expansion valve and a drain valve is located between the receiver and a connection downstream of the expansion valve; wherein the fluid circuit comprises a plurality of valves which are configured to be controlled based on a selected operating mode such that at least one of the outdoor exchanger and the heat recovery exchanger is connected to a discharge line of the compressor and in series with one of the other heat exchangers which is connected to a suction line of the compressor, with the expansion valve disposed between the heat exchangers; wherein the fill and drain valves are configured to be controlled to store a volume of refrigerant in the receiver so as to provide an effective refrigerant charge in the fluid circuit that corresponds to the selected operating mode.

Technologies described herein are directed to isolating or insulating at least portions of an evaporator coil within a climate control unit (CCU) of a TCCS so as to reduce or even eliminate adverse effects caused by a leaked working fluid. Such adverse effects may include a threat of ignition, asphyxiation of occupants, damage to cargo, and other harmful effects caused by emission of a noxious gas. A leak isolation structure is provided to isolate evaporator tubes of an evaporator coil from at least one of a plurality of turns of the evaporator coil.

A header includes a plurality of branch tubes and a header manifold. If refrigerant flowing into the header manifold forms a pattern of annular flow or churn flow, tips of the branch tubes inserted into the header manifold pass through a liquid-phase portion having a thickness δ [m] and reach a gas-phase portion. The thickness δ [m] of the liquid-phase portion is defined as δ=G×(1−x)×D/(4ρ.sub.L×U.sub.LS), where G is a flow speed [kg/(m.sup.2 s)] of the refrigerant, x is a quality of the refrigerant, D is an inside diameter [m] of the header manifold, ρ.sub.L is a liquid density [kg/m.sup.3] of the refrigerant, U.sub.LS is a reference apparent liquid speed [m/s] that is a maximum value within a range of variation in an apparent gas speed of the refrigerant flowing into a flow space of the header manifold. The reference apparent liquid speed U.sub.LS [m/s] is defined as G(1−x)/ρ.sub.L.

A header includes a plurality of branch tubes and a header manifold. If refrigerant flowing into the header manifold forms a pattern of annular flow or churn flow, tips of the branch tubes inserted into the header manifold pass through a liquid-phase portion having a thickness δ [m] and reach a gas-phase portion. The thickness δ [m] of the liquid-phase portion is defined as δ=G×(1−x)×D/(4ρ.sub.L×U.sub.LS), where G is a flow speed [kg/(m.sup.2 s)] of the refrigerant, x is a quality of the refrigerant, D is an inside diameter [m] of the header manifold, ρ.sub.L is a liquid density [kg/m.sup.3] of the refrigerant, U.sub.LS is a reference apparent liquid speed [m/s] that is a maximum value within a range of variation in an apparent gas speed of the refrigerant flowing into a flow space of the header manifold. The reference apparent liquid speed U.sub.LS [m/s] is defined as G(1−x)/ρ.sub.L.

A vapor compression system includes a first conduit fluidly coupling a liquid collection portion of a condenser and an evaporator, where the first conduit is configured to direct a first flow of refrigerant from the condenser to a first inlet of the evaporator and a second conduit fluidly coupling the liquid collection portion of the condenser and the evaporator, where the second conduit is configured to direct a second flow of refrigerant from the condenser to a second inlet of the evaporator via gravitational force, and where the first inlet is disposed above the second inlet relative to a vertical dimension of the evaporator.

A vapor compression system includes a first conduit fluidly coupling a liquid collection portion of a condenser and an evaporator, where the first conduit is configured to direct a first flow of refrigerant from the condenser to a first inlet of the evaporator and a second conduit fluidly coupling the liquid collection portion of the condenser and the evaporator, where the second conduit is configured to direct a second flow of refrigerant from the condenser to a second inlet of the evaporator via gravitational force, and where the first inlet is disposed above the second inlet relative to a vertical dimension of the evaporator.