An HVAC system includes a high-pressure subsystem and a low-pressure subsystem. After determining that refrigerant leak diagnostics should be performed, a controllable valve is closed between a condenser and compressor of the HVAC system. The compressor then operates until a predetermined input refrigerant pressure is reached. After the predetermined input refrigerant pressure is reached, operation of the compressor is stopped. After stopping operation of the compressor and waiting at least a predetermined wait time, the pressure in the low-pressure subsystem of the HVAC system is monitored. A rate of change of the pressure in the low-pressure subsystem is determined. If the rate of change is negative and a magnitude of the rate of change is greater than a threshold value, a leak location is determined to be in the low-pressure subsystem.

A control method and device for an air conditioner outdoor unit, an outdoor unit and an air conditioner are provided. The outdoor unit has a compressor, a first sensor for detecting an air exhaust pressure of the compressor, and a second sensor for detecting an air return pressure of the compressor. According to the method, a target pressure value is determined; an air exhaust pressure value detected by the first sensor or an air return pressure value detected by the second sensor is periodically obtained as a first pressure value; and the frequency of the compressor is adjusted according to the first pressure value and the target pressure value.

An HVAC system with a reheat coil is described, the system includes a compressor, a micro-channel condenser and an evaporator. A reversing valve is connected to the compressor, the micro-channel condenser and the reheat coil. The reversing valve is used to direct the refrigerant from the compressor to the micro-channel condenser in a normal mode, and to direct the refrigerant from the compressor to the reheat coil in a reheat mode. The reversing valve can be switched from normal mode to reheat mode when a high pressure condition is detected at an input to the micro-channel condenser, and switched back from reheat mode to normal mode when the high pressure condition has resolved or an amount of time has passed. In the normal mode the refrigerant is returned from the reheat coil into a refrigerant line between the evaporator and the compressor through a restrictor.

This disclosure aims to provide a technique for improving the accuracy of prediction. A first trained model for inferring labels for measurement data is generated based on a first data set. The first data set includes: combined data that are a combination of first measurement data, which are related to a first air conditioning apparatus, and labels set for the first measurement data; and second measurement data related to the first air conditioning apparatus.

A refrigerant leak management system includes a controller is configured to receive a signal indicative of a refrigerant pressure within a refrigerant circuit and determine whether the refrigerant pressure is indicative of a refrigerant leak in the refrigerant circuit. In response to determining that the refrigerant pressure is indicative of the refrigerant leak, the controller is configured to activate a fan configured to motivate air proximate the refrigerant circuit.

In an air-conditioning system including an outside air processing device and an air-conditioning device, an operation of either one of the outside air processing device or the air-conditioning device is stopped if a temperature/humidity state that is at least either the temperature or humidity of air in a target space is within a predetermined range and if the load factor of at least one of the outside air processing device or the air-conditioning device is below a predetermined lower limit.

A controller of an HVAC system is communicatively coupled to a liquid-side sensor and a shutoff switch. The controller stores measurements of a liquid-side property over an initial period of time. The controller detects that the shutoff switch is tripped at a first time stamp corresponding to an end of the initial period of time. The controller accesses the measurements of the liquid-side property. The controller determines, based on the measurements of the liquid-side property, that the liquid-side property has a decreasing trend. In response to determining that the liquid-side property has the decreasing trend, a malfunction of a blower of the system is determined to have caused the shutoff switch to trip.

An industrial installation having a primary supply circuit in which cooling water is conveyed and a consumer to which cooling water from the primary supply circuit is provided and which is connected to the primary supply circuit via a secondary supply circuit. An outward flow line of the secondary supply circuit is connected to an outward flow line of the primary supply circuit, and a return flow line of the secondary supply circuit is connected to a return flow line of the primary supply circuit. The outward flow line of the primary supply circuit is connected to a groundwater delivery line of a spring installation which has a groundwater delivery line through which groundwater can be conveyed from an aquifer and can be fed as cooling water into the outward flow line of the primary supply circuit. Also provided is a method for operating an industrial installation wherein the cooling water that is used is naturally occurring groundwater which is obtained from an aquifer with the aid of a spring installation.

An HVAC system includes a high-pressure subsystem and a low-pressure subsystem. After determining that refrigerant leak diagnostics should be performed, a controllable valve is closed between a condenser and compressor of the HVAC system. The compressor then operates until a predetermined input refrigerant pressure is reached. After the predetermined input refrigerant pressure is reached, operation of the compressor is stopped. After stopping operation of the compressor and waiting at least a predetermined wait time, the pressure in the low-pressure subsystem of the HVAC system is monitored. A rate of change of the pressure in the low-pressure subsystem is determined. If the rate of change is negative and a magnitude of the rate of change is greater than a threshold value, a leak location is determined to be in the low-pressure subsystem.

An air-conditioning apparatus includes: a heat-medium transfer device including a pump provided to transfer a heat medium that contains water or brine and transfers heat; a plurality of indoor units each of which includes an indoor heat exchanger provided to cause heat exchange to be performed between indoor air and the heat medium, and a flow control valve provided to adjust a flow rate of the heat medium that flows through the indoor heat exchanger, the plurality of indoor units being connected to the heat-medium transfer device by respective heat medium pipes; and a controller provided to control an opening degree of the flow control valve. The controller determines a valve opening-degree control range that is a control range of an opening degree of the flow control valve of each indoor unit, based on a flow-passage resistance depending on a length of a pipe that extends from the heat-medium transfer device to the indoor unit, such that the lower the flow-passage resistance, the smaller the valve opening-degree control range.