An authentication system acquires, as authentication information, information related to a device, information related to a user or information related to a user terminal, and information indicating that the user or the user terminal is in a vicinity of the device. The authentication system performs authentication of the acquired authentication information, and permits the user for whom or the user terminal for which the authentication is successful to manage the device.

Control systems are provided that provide thermodynamically decoupled control of temperature and relative humidity and/or reduce or prevent frost formation or remove previously-formed frost. The control systems herein may be included as a component of a heating, ventilation, air conditioning, and refrigeration system that includes a heat exchanger.

A control system is provided for controlling heating and/or cooling with a conditioning load such as fan coils and chilled beams. Based on user input and ambient conditions, the control system determines a desired temperature for the liquid entering the load and combines fresh supply liquid (e.g., from a chiller or boiler) with a portion of the liquid that has passed through the load, to achieve the target load input temperature for the liquid. A recirculation pump may be used to return a portion of the liquid exiting the load for mixing with the fresh supply liquid and a control valve may be used to adjust the ratio of fresh supply liquid and recirculated liquid to achieve the targeted temperature. The control systems can be compatible with a variety of liquid supply systems such as two- and four-pipe systems.

A system for analyzing a heating, ventilation, and air conditioning (HVAC) system includes: a processor; a display device controlled by the processor; a wireless communication module configured to receive a plurality of measurements from a plurality of different HVAC test instruments arranged to take measurements from the HVAC system, each of the HVAC test instruments providing one or more of the measurements; and a memory having instructions stored thereon where, when the instructions are executed by the processor, cause the processor to: receive the measurements from the different HVAC test instruments via the wireless communication module; convert the measurements to a common format; store the measurements in the common format in the memory; and display the measurements on the display device.

The disclosed technology includes systems and methods of reducing frost accumulation on a heat pump evaporator coil. The disclosed technology can include a heat pump assembly having an evaporator coil, a fan configured to direct air across the evaporator coil, a temperature sensor, and a controller configured to energize the fan to direct air across the evaporator coil when the temperature of the evaporator coil is below a threshold temperature.

A method of defrost operation optimization in a heat pump includes launching a heating mode after completion of a performed defrost operation, measuring, after launching the heating mode, a heat transfer capability, determining if the measured heat transfer capability is less than or equal to a predetermined heat transfer capability limit for a non-iced condition, and reinforcing a next defrost operation if the measured heat transfer capability is greater than the predetermined gap limit.

The invention provides a heat transfer system and a method for operating a heat transfer system in which a heat transfer fluid comprising or consisting of a phase change material (PCM) circulates in a cooling circuit. A combined state of phase value of the heat transfer fluid is determined based on information obtained from a sensor system including a temperature sensor and an electrical resistance sensor realized as two separate sensors or as one combined temperature-and-electrical-resistance sensor. The system and method can securely and effectively prevent a possible blocking of the channels of an indoor heat exchanger of the system by solidified PCM and an unwanted deposition of solid PCM (crystals) on heat transfer surfaces of the indoor heat exchanger.

A system for controlling flow of a fluid through a heat exchanger in a heating, ventilation, or air conditioning (HVAC) system includes a flow control device operable to adjust the flow of the fluid through the heat exchanger, temperature sensors positioned to obtain a temperature differential of the fluid across the heat exchanger, and a controller configured to compare the temperature differential to a threshold. Responsive to the temperature differential being less than the threshold, the controller is configured to calculate an adjusted setpoint for the flow control device as a function of both the temperature differential and the threshold and operate the flow control device to adjust the flow of the fluid through the heat exchanger in accordance with the adjusted setpoint.

A method for controlling an air handler includes providing a temperature setpoint to a smart valve in fluid communication with one or more coils of the air handler, providing to the smart valve an air temperature of air conditioned by the air handler, and modulating a valve position of the smart valve using the temperature setpoint, and the air temperature.

An air conditioner and a method for detecting an incorrectly connected pipe in an air conditioner are provided. The air conditioner may detect an incorrectly connected pipe by performing a serial pipe inspection when three or less indoor units are connected to an outdoor unit through pipes and performing a group pipe inspection when four or more indoor units are connected to the outdoor unit through the pipes. The structure may enable detecting the incorrectly connected pipe among pipes connecting the outdoor unit to the indoor units within a shorter time.