A heating, ventilation, and/or air conditioning (HVAC) unit includes a first sensor disposed adjacent to an inlet of an evaporator configured to receive an airflow. The HVAC unit includes a second sensor disposed adjacent to an outlet of a reheat coil positioned downstream of the evaporator and configured to expel the airflow. The HVAC unit also includes a controller configured to regulate operation of a modulating reheat valve to adjust flow of a working fluid in thermal communication with the airflow to control a difference between a measurement of the first sensor and a measurement of the second sensor.

The purpose of the present invention is to propose a device for detecting refrigerant leaks in a refrigeration cycle. The device can be applied irrespective of whether a liquid-receiving tank is present, has a simple configuration, and can be installed easily and inexpensively as a retrofit. Moreover, the device is configured so as to detect the presence of leaks without stopping operation of the equipment, and is innovative and of exceptional utility such that there is no decrease in the equipment operation rate as caused by detection of leaks. Provided is a device for detecting refrigerant leaks in a refrigeration cycle, the device comprising an ultrasonic wave transmitter 1 for transmitting ultrasonic waves having a prescribed frequency, an ultrasonic wave receiver 2 for receiving the ultrasonic waves transmitted by the ultrasonic wave transmitter 1, an ultrasonic wave reception determination unit 3 for determining whether the ultrasonic wave receiver 2 has received the ultrasonic waves transmitted by the ultrasonic wave transmitter 1, and a leak reporting unit 4 for externally reporting a leak event when the ultrasonic wave reception determination unit 3 has determined that the ultrasonic wave receiver 2 has not received the ultrasonic waves transmitted by the ultrasonic wave transmitter 1.

A system or a method for performing capacitive sensing of humidity/liquid, primarily in conductive or non-conductive liquid/gas mixtures, having a control unit and at least first and second sensor electrodes, the capacitance between the first and the second electrodes being measured. To measure humidity/liquid in a circulating gas/liquid mixture at least one of the sensor electrodes is formed as a tube which is placed in the liquid/gas mixture. Based on the capacitance measurements, a calculation of at least one dataset for control of a second system is performed. The tube can be more or less filled up with liquid or gas and the capacitance can be measured as it depends on the content around or inside the tube, and if a dry gas is there will be one value of capacitance and in a situation where the gas is being replaced by liquid, the capacitance value will change rapidly.

An evaporator includes a housing having a first end longitudinally opposing a second end. The evaporator includes an inlet disposed on the housing and configured to receive a fluid. The evaporator also includes a tube bundle disposed in the housing and configured to evaporate the fluid to provide a vapor stream arranged to exit through an outlet on the housing. Additionally, the evaporator has a flow balancer provided between the tube bundle and the outlet on the housing, and the flow balancer is configured to balance refrigerant quality between the first end and the second end of the evaporator by controlling the vapor stream.

Systems and methods for providing an improved strategy for controlling a variable speed water pump in a vehicle. In some embodiments, more than one water pump speed function is calculated based on values obtained from vehicle sensors, and a controller chooses among the water pump speed function results to set a water pump speed. In some embodiments, the water pump speed is increased when driveline torque is greater than a threshold amount for an amount of time that varies based on the driveline torque. In some embodiments, ambient temperature is considered while determining whether the water pump should provide full coolant flow to an auxiliary coolant loop of a trailer.

An air-conditioning apparatus includes at least one indoor unit with intake and blow-out ports, a refrigerant gas sensor disposed in an air flow path inside the indoor unit; and a control device. The indoor unit has an indoor fan drawing indoor air in from the intake port and blowing conditioned air out from the blow-out port, an indoor temperature sensor detecting temperature of the indoor air, an indoor-side refrigerant circuit circulating a refrigerant having a greater specific gravity when gasified than air and producing conditioned air from the indoor air, and at least one refrigerant temperature sensor detecting refrigerant temperature in the refrigerant circuit. The control device drives the indoor fan in accordance with at least one of an operation mode and a detection value of the at least one refrigerant temperature sensor, and detects refrigerant leakage using the refrigerant gas sensor.

When the anomaly determination mode starts, the controller brings the decompressor into the first decompression amount state, and operates a compressor at a first speed. The controller is configured to store a value of the related physical quantity measured by the detector at a time point at which a first time elapses from a start of the anomaly determination mode, as a first measurement value, and thereafter switch the decompressor to the second decompression amount state from the first decompression amount state, store a value of the related physical quantity measured by the detector after the decompressor is switched to the second decompression amount state from the first decompression amount state, as a second measurement value, and determine that there is anomaly in the refrigerant circuit when a value obtained by subtracting the first measurement value from the second measurement value is larger than a first anomaly determination value.

A control system for a refrigeration circuit having one or more working fluid refrigerant sensors capable of measuring the fluid energy value of the refrigerant along a low side of the refrigeration circuit and regulating the flow of refrigerant to the circuit low side through reference to expected refrigerant fluid energy values.

A multi-split air-conditioning system, and a method for calculating a heat exchange capacity thereof. The method includes: acquiring a total heat exchange capacity of a multi-split air-conditioning system; acquiring a pressure difference between two pressure measurement points on each air pipe; acquiring the distance between the two pressure measurement points on each air pipe; acquiring the pipe diameter of each air pipe; acquiring the friction factor of each air pipe; acquiring the density of a heat exchange medium in each air pipe; and according to the total heat exchange capacity of the multi-split air-conditioning system, the pressure difference and distance between the two pressure measurement points on each air pipe, the pipe diameter and friction factor of each air pipe, and the density of the heat exchange medium in each air pipe, calculating a heat exchange capacity of each indoor unit.

An outdoor unit control unit 200 has a defrosting operation condition table 300a that defines an activation rotational speed Cr in accordance with a total sum of flow rate coefficients Cva that is a total sum of flow rate coefficients Cv representing capacities of indoor expansion valves 52a to 52c. The outdoor unit control unit 200 calculates the total sum of the flow rate coefficients Cva by adding the flow rate coefficient Cv of each of the indoor expansion valves 52a to 52c, and refers to the defrosting operation condition table 300a, so as to determine the activation rotational speed Cr. Then, the outdoor unit control unit 200 activates a compressor 21 at the determined activation rotational speed Cr when starting a defrosting operation, maintains this activation rotational speed Cr for a predetermined time from the start of the defrosting operation, and drives the compressor 21.