Abstract:
The present invention provides for a system for calibrating operation of a compressor unit in a heating, ventilation, and air conditioning (HVAC) system. A measuring device measures an operating parameter of the HVAC system at a position where the measuring device is mounted on a refrigerant line of the HVAC system. The measuring device switches states when the value of the measured operating parameter reaches a switching value. A controller estimates a value of the first operating parameter at the position where the first measuring device is mounted on the refrigerant line, and the controller determines whether the estimated first operating parameter is within a threshold percentage of the switching value.
Abstract:
Controls for chillers with variable speed and variable geometry compressors are disclosed. In exemplary embodiments, a centrifugal compressor equipped with a variable frequency drive and variable inlet guide vanes may be utilized. A controller is operable to determine a chiller capacity command, a speed command, and a vane position command. The speed command and vane position command may maintain system operation at or near a surge control boundary over one or more capacity ranges to enhance efficiency and deviate from the surge control boundary over certain capacity ranges to improve controllability or avoid control aberrations.
Abstract:
A system and methods associated therewith for providing a load controller for a refrigerant recovery unit are disclosed. The load controller can be controlled to operate when the current drawn by the motor increases due to pressure changes caused by abnormal refrigerant flow or during activation of the motor in order to lower the pressure. In some aspects of the present disclosure, the load controller can lower the pressure by recirculating some of the pressure load through the opening of a compressor bypass loop line. In some embodiments, the current/pressure load may be monitored during the operation of the refrigerant recovery unit and set to act as an emergency shut off and alert system to the user when the system malfunctions.
Abstract:
A compressor, which is susceptible to protective shutdowns when certain operating conditions are sensed, includes a control feature wherein, when the compressor is restarted after a period of time, it may be caused to operate in an unloaded mode such that a reoccurrence of the shutdowns is less likely.
Abstract:
A scroll compressor is provided with economizer injection ports, which extend through the wrap of one of the scroll members. Preferably the injection ports are formed through a so-called “hybrid” wrap, which has a varying thickness. The other scroll member is provided with grooves in its base plate. The injection of economizer fluid occurs only during a portion of the orbiting cycle when the injection port and corresponding grooves are aligned with each other. An indentation is formed into the wrap that includes the injection port. The indentation is spaced circumferentially from the injection port. The indentation communicates with the groove, such that refrigerant can pass from the injection port, into the groove, and through the indentation into a compression chamber. This increases the injection time allowing more fluid to be injected into the compression chamber, and provides the scroll compressor designer with greater freedom to achieve desired flow of economizer fluid into the compression chambers.
Abstract:
A heat pump four-way valve selectively routes refrigerant to either indoor or outdoor heat exchanger. The position of the plunger inside the valve can also be adjusted to selectively provide a hot gas by-pass function by routing a portion of refrigerant from discharge to suction line. The four-way valve preferably is positioned such that it can either operate in a conventional heat pump mode, or can be positioned to perform an unloaded hot gas by-pass function.
Abstract:
A cooling system controller controls the capacity of a variable capacity compressor based upon the temperature of a housing being cooled, the suction pressure of the compressor or both of these criteria. The cooling system controller is capable of controlling either single-evaporator or multiple-evaporator refrigeration systems. The multiple-evaporator systems can have evaporators of similar temperatures or of mixed temperatures. The controller also allows the use of one or more condenser fans that are operated in a lead/lag fashion to control the cooling capability of the system.
Abstract:
A cooling system controller controls the capacity of a variable capacity compressor based upon the temperature of a housing being cooled, the suction pressure of the compressor or both of these criteria. The cooling system controller is capable of controlling either single-evaporator or multiple-evaporator refrigeration systems. The multiple-evaporator systems can have evaporators of similar temperatures or of mixed temperatures. The controller also allows the use of one or more condenser fans that are operated in a lead/lag fashion to control the cooling capability of the system.
Abstract:
A refrigeration/heating system for cooling or heating an area includes a condenser for removing heat from the system to an external environment, an evaporator for receiving heat from the area to be cooled or delivering heat to the area to be heated, and a compressor for raising the pressure and the temperature of a refrigerant. The compressor has at least one cylinder bank and an unloader connected to the cylinder bank for loading and unloading the cylinder bank. Pressure transducers measure the suction and discharge pressures of the compressor when the state of a cylinder bank is changed from a loaded to an unloaded state. A processor uses the suction and discharge pressures in the various states to determine the operational condition of either unloader. By varying the loading and unloading of a pair of cylinder banks, the processor can also use various suction and discharge pressures to determine if a problem exists within either cylinder bank or unloader.
Abstract:
In a refrigerating machine having a heat exchanger, a rated compressor for which the frequency of driving power is fixed, a power control mechanism which is disposed in the compressor and serves to return a part of the refrigerant in the cylinder under a compressing process to the cylinder under sucking process, a refrigerant return mechanism for returning a part of the refrigerant discharged from the compressor to a refrigerant suction side of the compressor, and a controller for selectively controlling the power control mechanism and the refrigerant return mechanism to make the output power variable. A pole-changeable type compressor having a pole changer may be used in place of the rated compressor having the power control mechanism, and the output power is made variable by selectively controlling the pole changer and the refrigerant return mechanism.