A refrigerant condition detection device (40A) according to an embodiment includes: a temperature information acquisition unit (41) that acquires a temperature of a refrigerant flowing out from the condenser of a refrigeration circuit having a compressor, the condenser, an expansion valve, and an evaporator, and also acquires a temperature of a cooling fluid before it cools the refrigerant in the condenser; and a refrigerant condition determination unit (42) that determines that a leakage or shortage of the refrigerant occurs, when a difference between the temperature of the refrigerant and the temperature of the cooing fluid, which are acquired by the temperature information acquisition unit (41), exceeds a threshold value previously recorded.

Chiller control systems and methods for chiller control use iterative modeling of cooling towers, heat exchangers, and pumps to determine the feasibility of integrated free cooling and the ability to take advantage of free cooling. The control systems and control methods can further include selecting the parameters for operating in the free cooling or integrated free cooling mode to improve efficiency and/or reduce energy consumption when operating in these modes. The models can have inputs and outputs that feed into one another, and converge at a solution over multiple iterations. The feasibility of integrated free cooling can be based on providing cooling to a cooling load process fluid at a heat exchanger. The availability of free cooling can be based on the cooling provided at the heat exchanger achieving a target temperature for the cooling load process fluid.

A method of controlling an HVAC circuit, comprises allowing refrigerant to circulate within the HVAC circuit, wherein the HVAC circuit comprises an evaporator coil, a condenser coil, at least one fan configured to provide airflow to the condenser coil, at least one expansion valve, and at least one compressor. The method continues by receiving a temperature measurement and determining based on the temperature measurement, a minimum fan speed configured to avoid pressure spikes within the condenser coil. The method concludes by sending a signal to the at the least one fan to direct the at least one fan to spin at a rate greater than or equal to the minimum fan speed when the measured temperature is less than a predetermined temperature, wherein, when the refrigerant circulates through the condenser coil, the minimum fan speed is greater than zero rotations per minute.

A refrigeration system includes a receiver, a gas bypass valve, a parallel compressor, and a controller. The gas bypass valve and the parallel compressor are fluidly coupled to an outlet of the receiver in parallel and configured to control a pressure of a gas refrigerant in the receiver. The controller is configured to switch from operating the gas bypass valve to operating the parallel compressor to control the pressure of the gas refrigerant in the receiver in response to a value of a process variable crossing a switchover setpoint. The value of the process variable depends on an amount of the gas refrigerant produced by the refrigeration system. The controller is configured to automatically adjust the switchover setpoint in response to the amount of the gas refrigerant produced by the refrigeration system being insufficient to sustain operation of the parallel compressor.

An apparatus and a method for detecting refrigerant leakage in an air source heat pump system. The method for detecting refrigerant leakage in an air source heat pump system includes the following steps in a cooling mode: S110: obtaining a running parameter of an air source heat pump system, wherein the running parameter at least includes a compressor rotational speed; S120: comparing the running parameter with a preset running parameter range; S130: updating a cumulative score when the running parameter falls within the preset running parameter range; and S140: when the cumulative score exceeds a predetermined cumulative score, determining that refrigerant leakage occurs, and when the cumulative score does not exceed the predetermined cumulative score, return to step S110.

A sorption heat pump having an evaporator containing a working fluid to evaporate the fluid to produce a gas, a sorber containing a sorption material to sorb the gas during a sorption phase, a vapor pathway connecting the evaporator and sorber, and a thermal control unit controlling the rate of vapor flow between the evaporator and sorber through the pathway, and being selectively operable to permit, stop and restart the flow of gas through the pathway. The pump may be used with a compartment storing temperature sensitive material. The evaporator may be positioned inside and the sorber outside the compartment, or the sorber may be positioned inside and the evaporator outside the compartment. The pump may be used in an apparatus including both cool and warm compartments, with an insulation layer in each. A method is disclosed for reusing the pump after the sorption material has been sorbed.

A refrigeration plant with a cooling circuit, comprising at least one peripheral unit having a refrigeration machine for refrigerating a storage compartment; the refrigeration machine having a heat exchanger connected to the cooling circuit for dissipating heat to a secondary fluid flowing therein; a cooling apparatus connected to the cooling circuit for cooling the secondary fluid; a control device connected to the cooling apparatus and configured to operate the cooling apparatus so as to maintain at least an operating temperature of the secondary fluid within at least a corresponding reference range or to equalize it to at least a corresponding target value.

Systems, apparatus and methods for efficiently operating a chiller plant while minimizing or eliminating the occurrence of centrifugal compressor surge. Taking into account chiller design specifications and current operating conditions, a compressor lift point at which surge is predicted to occur is established. Minima and maxima for various chiller setpoints that avoid or eliminate the occurrence of compressor surge are imposed on setpoints provided by a conventional optimizing chiller controller. The chiller system is operated in accordance with the resultant anti-surge setpoints. Energy savings is realized by modulating coolant tower flow to enable the compressor to operate at near-surge conditions while preventing the onset of actual surge.

Embodiments of the present disclosure are directed toward systems and method for cooling a refrigerant flow of a refrigerant circuit with a cold cooling fluid flow from a thermal storage unit to generate a warm cooling fluid flow, thermally isolating the cold cooling fluid flow and the warm cooling fluid flow in the thermal storage unit, and cooling the warm cooling fluid flow from the thermal storage unit in a chiller system to at least partially produce the cold cooling fluid flow.

A device for controlling the temperature of an external fluid. The device including a compressor for compressing an internal fluid, a first heat exchanger in a temperature control circuit for transferring thermal energy between the internal fluid and the external fluid. The device is further configured for use within a system for controlling the temperature of blood.