The invention relates to a method for cooling and/or liquefying a user fluid flow the method using a cooling and/or liquefying system comprising a low-temperature refrigeration device, the refrigeration device comprising a working circuit forming a loop and containing a working fluid, the refrigeration device comprising a cooling exchanger intended to extract heat from the user fluid flow by heat exchange with the working fluid circulating in the working circuit, the working circuit forming a cycle comprising, in a series: a compression mechanism a cooling mechanism, an expansion mechanism, and a reheating mechanism, the system comprising a pipe for circulation of the user fluid flow to be cooled in heat exchange with the cooling exchanger of the refrigeration device, the method comprising a step of cooling a user fluid flow in the cooling exchanger and after this cooling step, a step of cleaning impurities solidified in the cooling exchanger, the cleaning step comprising stopping of the refrigeration device and simultaneously, circulation of a user fluid flow in the cooling exchanger.

An expansion valve control method for a multi-split air-conditioning system to solve the problem of detecting leakage of an expansion valve of a multi-split air-conditioning system. The system includes an outdoor unit and a plurality of indoor units connected to the outdoor unit, each of the indoor units is connected to the outdoor unit by a first pipeline and a second pipeline. The expansion valve control method includes acquiring an indoor temperature of an environment where an indoor unit is located; acquiring the temperature of a first pipeline of the indoor unit and the temperature of a second pipeline of the indoor unit when the indoor unit is in a shutdown state; and according to at least the indoor temperature of the environment where the indoor unit is located, determining the leakage condition of an expansion valve of the indoor unit.

Disclosed is a swirl generator for an evaporator, having: a body that extends along a body-center axis between opposing inlet and outlet ends, and includes: a fluid inlet at the inlet end; an outer surface that, at that the outlet end, defines an outlet region with a curved outer boundary forming a convex curve that extends radially inward from an outer diameter surface of the body to an outer axial surface of the body; a center passage formed within the body that extends from the inlet towards the outlet along the body-center axis; and a swirl passage formed at the outlet end of the body, the swirl passage extending between the center passage and the curved outer boundary along a swirl passage axis, whereby a fluid entering from the inlet exits the body at the curved outer boundary, the swirl passage axis forming an acute angle with the body-center axis.

A method of improving the efficiency of the heat exchange system using variable superheat and sub cooling values for a wide range of ambient conditions is provided. The heat exchange system comprises an efficiency enhancing apparatus positioned between the condenser and evaporator. Data analytics software module and artificial intelligence techniques are used to obtain optimum system parameters for achieving maximum efficiency.

A heat exchanger includes a plurality of fins and a plurality of tubes that are inserted into the fins and that allow refrigerant to flow in the tubes. The tubes include first heat transfer tubes and second heat transfer tubes. Each of the first heat transfer tubes includes grooves formed in an inner surface of the first heat transfer tube, and has an inside diameter Da and a groove depth Ta. Each of the second heat transfer tubes has an inner surface smoothed, has an inside diameter Db, and is connected to an associated one of the first heat transfer tubes. Da−2×Ta≤Db is satisfied.

An energy efficient heat pump for a heating, ventilation, and air conditioning (HVAC) system includes a vapor compression circuit, a heat exchanger of the vapor compression circuit configured to place a working fluid in a heat exchange relationship with an air flow directed across the heat exchanger, and a conduit system of the vapor compression circuit. The conduit system of the vapor compression circuit is configured to direct the working fluid into the heat exchanger and to receive the working fluid from the heat exchanger, wherein the conduit system is configured to direct the working fluid into the heat exchanger to place the working fluid in a counterflow arrangement with the air flow directed across the heat exchanger in a cooling mode of the heat pump and in a heating mode of the heat pump.

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.2s)] 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.

In one embodiment, an apparatus includes an insert for an evaporator coil. The insert is a curved wire located within the evaporator coil. The insert for the evaporator coil reduces refrigerant charge in the evaporator coil and causes refrigerant flowing through the evaporator coil to change direction.

In an air-conditioning apparatus in which air sucked into a casing of an outdoor unit by a fan is discharged from an upper portion of the casing, each of liquid header portions is configured to be connected with each of heat transfer tubes of a plurality of divided regions formed by dividing the outdoor heat exchangers in an up and down direction. Further, a shunt is configured to supply two-phase refrigerant, in which quality is adjusted by a gas-liquid separator, to each of the liquid header portions. To each of the liquid header portions, the shunt supplies the two-phase refrigerant of the amount corresponding to the air quantity of the divided region connected to each of the liquid header portions.

In one embodiment, an apparatus includes an insert for an evaporator coil. The insert is located within the evaporator coil. The insert for the evaporator coil reduces refrigerant charge in the evaporator coil and causes refrigerant flowing through the evaporator coil to change direction. The insert for the evaporator coil includes a solid core and a plurality of support legs.