A system and method for controlling the operation of heating, ventilating, and air conditioning (HVAC) equipment so as to achieve a desired range of a sound pressure level and/or a sound power level is described. The system and method can lead to a desired range of a sound pressure level and/or a sound power level for a zone using equipment that is typically included in HVAC systems. Such control of equipment can be important for privacy and comfort requirements.

A cooling system is provided and includes pump, condenser fan, and control modules. The pump module controls a pump to pump a cooling fluid through a cooling circuit. The condenser fan module controls a condenser fan to transfer air across a condenser of the cooling circuit. The control module, while operating in a pumped refrigerant economizer mode or a mixed mode, determines a requested CFC percentage. The pump module activates the pump if the requested CFC percentage is greater than or equal to a predetermined CFC percentage. The condenser fan module: if the requested CFC percentage is greater than or equal to the predetermined CFC percentage, activates the condenser fan or operates the condenser fan at least at a minimum speed; and based on the requested CFC percentage, adjusts a speed of the condenser fan between the minimum speed and a maximum permitted speed to provide the requested CFC percentage.

Heating, ventilating and air conditioning are provided to a temporary, flexible shelter, especially in a rugged, remote and/or extreme environment, including locations and/or conditions where access to electric power may be limited and/or expensive. A portable system may include a light weight HVAC unit, with variable-speed components that are dynamically managed for efficiency, reliability and safety, and a flexible, self-insulating duct for connecting the HVAC unit to the temporary shelter.

A system and a method that utilizes wet proppants when creating fracturing fluid by receiving wet fracturing sand at a surge tank, vibrating the wet fracturing sand located within the surge tank, liquefying the wet fracturing sand within the surge tank based on the vibration, and metering the liquefied wet fracturing sand from the surge tank to a blending tub.

A system and method are provided including a system controller for a refrigeration or HVAC system having a compressor rack with a compressor and a condensing unit with a condenser fan. The system controller monitors and controls operation of the refrigeration or HVAC system. A rack controller monitors and controls operation of the compressor rack and determines compressor rack power consumption data. A condensing unit controller monitors and controls operation of the condensing unit and determines condensing unit power consumption data. The system controller receives the compressor rack power consumption data and the condensing unit power consumption data, determines a total power consumption of the refrigeration or HVAC system, determines a predicted power consumption or a benchmark power consumption for the refrigeration system, compares the total power consumption with the predicted power consumption or the benchmark power consumption, and generates an alert based on the comparison.

A refrigerator, a sealed refrigerant system, and method are provided where the refrigerator includes at least a refrigerated compartment and a sealed refrigerant system including an evaporator, a compressor, a condenser, a controller, an evaporator fan, and a condenser fan. The method includes monitoring a frequency of the compressor, and identifying a fault condition in the at least one component of the refrigerant sealed system in response to the compressor frequency. The method may further comprise calculating a compressor frequency rate based upon the rate of change of the compressor frequency, wherein a fault in the condenser fan is identified if the compressor frequency rate is positive and exceeds a condenser fan fault threshold rate, and wherein a fault in the evaporator fan is identified if the compressor frequency rate is negative and exceeds an evaporator fan fault threshold rate.

A method for defrosting a heat pump includes operating a fan at a particular speed. The fan is positioned to circulate air across the exterior coil of the heat pump. The method also includes measuring a power of the fan while the fan is operating at the particular speed and initiating a defrost of the exterior coil of the heat pump when the power of the fan is less than a threshold power.

An internal temperature adjusting device includes a heat pump, an internal heat exchanger, and an external heat exchanger. The internal heat exchanger is configured to function as one of an evaporator or a condenser of the heat pump, and exchange heat between a heat medium and air inside the container. The external heat exchanger is configured to function as the other one of the evaporator or the condenser, and exchange heat between the heat medium and air outside the container. The external heat exchanger includes a plurality of heat exchanging members separated from each other. According to the internal temperature adjusting device, drainage of the external heat exchanger as a whole can be secured.

A system and a method that utilizes wet proppants when creating fracturing fluid by receiving wet fracturing sand at a surge tank, vibrating the wet fracturing sand located within the surge tank, liquefying the wet fracturing sand within the surge tank based on the vibration, and metering the liquefied wet fracturing sand from the surge tank to a blending tub.

A control method and device and an air conditioner are provided. The air conditioner has an outdoor condenser, an indoor evaporator, a first electronic expansion valve, a throttle valve, and a heat dissipation coolant pipe arranged in an electric control box. By utilizing the control method and device, the air conditioner uses the heat dissipation coolant pipe to dissipate heat from the electric control box of the air conditioner. The heat generated by the electric control box can thus be timely removed. The temperature of the elements of the air conditioner can be lowered and the reliability and service life of the air conditioner can be improved.