A method for refrigerant charge determination in a cooling circuit including a low-pressure section and a high-pressure section. At least one compressor unit generates a compression flow of refrigerant from said low-pressure section to said high-pressure section. At least one expansion device generates an expansion flow of refrigerant from said high-pressure section to said low-pressure section. A heat-releasing heat exchanger in said high-pressure section cools and condenses compressed refrigerant. A heat-absorbing heat exchanger in said low-pressure section vaporizes said expanded refrigerant. The method includes loading refrigerant from said low-pressure section into said high-pressure section. An unloading step admits the expansion flow of refrigerant loaded in said high-pressure section into said low pressure section and determines the amount of refrigerant flowing in said unloading step. The method includes calculating the refrigerant charge in said cooling circuit, based on the amount of refrigerant flowing from said high-pressure section to said low-pressure section.

A system for controlling or optimizing the performance of a vapor compression system by modifying the actuator commands via an output interface, that realizes thermofluid property functions and their derivatives as spline functions which are represented in a coordinate system that is aligned with a fluid saturation curve. The system includes an interface configured to receive measurement data from sensors, a memory configured to store thermofluid property data and computer-executable programs including a B-spline method, and a processor for performing the computer-implemented method. The processor is configured to take as input two thermofluid property variables, and compute a coordinate transformation in which one axis of the coordinates is aligned with the liquid and vapor saturation curves. In the saturation-curve aligned coordinates, a spline function represents the thermofluid property function, with coefficients and knots stored in memory. The spline function is constructed in a manner such that derivatives of the thermofluid property function may be discontinuous across the saturation curve.

The present disclosure relates to a method for determining an efficiency curve of a chiller that includes operating a chiller over a range of operating capacities, measuring a temperature of water entering the chiller at an initial capacity, measuring a temperature of water exiting the chiller at the initial capacity, measuring a power consumption of the chiller at the initial capacity, calculating an initial efficiency of the chiller at the initial capacity, measuring a plurality of temperatures of water entering the chiller at a plurality of capacities, measuring a plurality of temperatures of water exiting the chiller at each of the plurality of capacities, measuring a plurality of power consumptions at each of the plurality of capacities, calculating a plurality of efficiencies at each of the plurality of capacities, and generating an efficiency curve for the chiller with the initial efficiency and the plurality of efficiencies.

An air-conditioning apparatus includes a four-way valve, a first three-way valve and a second three-way valve each having a closed port, a compressor, an indoor heat exchanger, an expansion valve, a first outdoor heat exchanger, a second outdoor heat exchanger, a bypass expansion valve, a check valve, a discharge temperature sensor, an indoor pipe temperature sensor, an indoor temperature sensor, a current sensor, and a controller configured to detect switching failure at the four-way valve, the first three-way valve, and the second three-way valve. The controller is configured to detect switching failure at the four-way valve, the first three-way valve, or the second three-way valve by using the temperatures measured by the discharge temperature sensor, the indoor pipe temperature sensor, and the indoor temperature sensor and the current in consideration of an operation status.

A chiller includes an evaporator, a compressor including a prime mover, a first pressure sensor that detects a first pressure in the evaporator, a second pressure sensor that detects a second pressure in a condenser, and a controller. The controller determines a predicted energy level of the compressor based on the first pressure and the second pressure, the predicted energy level associated with liquid droplet flow into the compressor, compares the predicted energy level to an operating energy level, and modifies the at least one of the input power and the input current to the prime mover based on the comparison satisfying a modification condition.

A device for refuelling containers with pressurized gas, comprising a pressurized gas source, a transfer circuit intended to be removably connected to a container, the device comprising a refrigeration system for cooling the gas flowing from the gas source prior to its entering into the container, the refrigeration system comprising a refrigerant cooling loop circuit comprising, arranged in series, a compressor, a condenser section, an expansion valve and an evaporator section, the refrigeration system comprising a cold source in heat exchange with the condenser section and a heat exchanger located in the transfer circuit, the device comprising an electronic controller connected to the expansion valve and configured for controlling cooling power produced by the refrigeration system via the control of the opening of the expansion valve, the device comprising a differential temperature sensor system measuring the difference between the temperature of the refrigerant in the refrigerant cooling loop circuit at the outlet of the heat exchanger and the temperature of the refrigerant in the cooling loop circuit at the inlet of the heat exchanger, the electronic controller being configured for controlling the cooling power produced as a function of this temperature differential.

A dual reclaim coil with a smart control application is provided that allows the refrigerant inlet to the HVAC unit switch between the two sides of the condenser is aimed to use the high temperature and pressure of the condenser/gas cooler outlet while a CO.sub.2 refrigerant system is operating above critical point. This occurs in hot ambient conditions, when the need for heating in the space is not as great as in the wintertime and the available heat at the condenser/gas cooler's outlet is sufficient to satisfy the heating load. This also mitigates space overcooling, while increasing the CO.sub.2 transcritical system's efficiency by subcooling the refrigerant for applications involving dehumidification HVAC systems which often results in a phenomenon called “overcooling” during the dehumidification season.

A parameter estimation apparatus of an embodiment of the present invention is provided with a model reduction processor and a parameter estimator. The model reduction processor generates reduced order models by reducing order of a simulation model on the basis of measurement data sets and conditions for model order reduction possibility. The parameter estimator estimates values of parameters of the reduced order models on the basis of the reduced order models and the measurement data sets corresponding to the reduced order models. Further, after estimating a first value for a first parameter of a first reduced order model based on a first measurement data set, the parameter estimator applies the first value to the first parameter of a second reduced order model based on a second measurement data set.

An icemaking system includes: a refrigerant circuit that executes a vapor compression refrigeration cycle; a circulation circuit that circulates solution as a cooling target of the refrigerant circuit; and a control device that controls refrigerant evaporation temperature at the refrigerant circuit. The circulation circuit includes a solution flow path of: an ice generator; a solution tank that stores the solution; and a pump that pressure feeds the solution to the solution flow path. The refrigerant circuit includes: an evaporator of the ice generator; a compressor; a condenser; and an expansion valve. The control device includes a central processing unit (CPU) that adjusts to lower evaporation temperature at the evaporator as the solution has higher solute concentration.

A multi-connection air conditioning system and a method for calculating a heat exchange amount thereof includes a plurality of indoor units, and the method includes: obtaining a total heat exchange amount of the multi-connection air conditioning system; obtaining inlet air temperature of each indoor unit; obtaining a two-phase saturation temperature of each indoor unit; obtaining an air supply volume of each indoor unit; obtaining a heat exchange area of each indoor unit; and calculating a heat exchange amount of each indoor unit according to the total heat exchange amount of the multi-connection air conditioning system, the inlet air temperature of each indoor unit, the two-phase saturation temperature of each indoor unit, the air supply volume of each indoor unit, and the heat exchange area of each indoor unit. Thus the user can monitor the heat exchange amount of each indoor unit so that they can be managed with separate targets.