A control unit is configured to set a rotation speed of a compressor to be lower than that in a defrosting operation and set an opening degree of a pressure reducing device to be equal to or greater than that in the defrosting operation during a first control time after completion of the defrosting operation, stop the compressor and set the opening degree of the pressure reducing device to be less than that in the first control time during a second control time after lapse of the first control time, and control a refrigerant circuit switching device to resume a heating operation after lapse of the second control time.

A dehumidifier apparatus (10) to provide low humidity air to an enclosure. The apparatus (10) includes an outer housing (11) providing six air passages (12 to 17). Also located in the outer housing (11) is a heat exchanger (22) that provides two air paths between which heat is exchanged. The apparatus (10) further includes coils (27, 28 and 29) as well as a motorised damper (18) and fan (19). The apparatus (10) further includes a refrigeration circuit (73) and controller (30), with the controller (30) operating the damper (18), fan (19) and circuit (73) to provide low dew point dehumidified air.

A freeze protection system for a heating, ventilation, or air conditioning (HVAC) system is shown. The freeze protection system includes a temperature sensor positioned at an inlet of a coil within which a liquid is at risk of freezing, and a controller comprising a processor and memory. The memory stores instructions that are executed by the processor. The processor is instructed to obtain a measured temperature of the liquid at the inlet of the coil from the temperature sensor, compare the measured temperature of the liquid at the inlet of the coil with a freeze prevention temperature threshold, engage a freeze prevention action in response to a determination that the measured temperature of the liquid at the inlet of the coil is less than or equal to the freeze prevention temperature threshold.

A freeze protection system for a heating, ventilation, or air conditioning (HVAC) system is shown. The freeze protection system includes a temperature sensor positioned at an inlet of a coil within which a liquid is at risk of freezing, and a controller comprising a processor and memory. The memory stores instructions that are executed by the processor. The processor is instructed to obtain a measured temperature of the liquid at the inlet of the coil from the temperature sensor, compare the measured temperature of the liquid at the inlet of the coil with a freeze prevention temperature threshold, engage a freeze prevention action in response to a determination that the measured temperature of the liquid at the inlet of the coil is less than or equal to the freeze prevention temperature threshold.

The present invention relates to a heat exchanger, a method for manufacturing the same, a heat recovery ventilator (HRV) including the same, and a method for defrosting and checking operations thereof.

In an air-conditioning apparatus, a heat source side heat exchanger, intermediate heat exchangers, and use side heat exchangers are formed in separate bodies respectively and adapted to be disposed at separate locations one another. In a heat medium circulation circuit where the intermediate heat exchanger and the use side heat exchanger are connected, temperature sensors are installed. An anti-freezing operation mode is provided in which, when the detection temperatures of the temperature sensors become equal to or lower than a set temperature Ts while a compressor or pumps are stopped, the heat medium is circulated to perform anti-freezing of the heat medium.

An example HVAC system includes an HVAC component, and an HVAC control configured to control the HVAC component according to an HVAC system configuration parameter. The HVAC control includes a controller wireless interface and a memory. The system also includes a mobile device having a user interface and a mobile wireless interface in wireless communication with the controller wireless interface of the HVAC control. The mobile device is configured to display the HVAC system configuration parameter on the user interface, receive user input settings for the HVAC system configuration parameter, and wirelessly transmit the received user input settings to the controller wireless interface of the HVAC control. The HVAC control is configured to store the received user input settings in the memory of the HVAC control to control the HVAC component. Example methods of controlling an HVAC system are also disclosed.

An example HVAC system includes an HVAC component, and an HVAC control configured to control the HVAC component according to an HVAC system configuration parameter. The HVAC control includes a controller wireless interface and a memory. The system also includes a mobile device having a user interface and a mobile wireless interface in wireless communication with the controller wireless interface of the HVAC control. The mobile device is configured to display the HVAC system configuration parameter on the user interface, receive user input settings for the HVAC system configuration parameter, and wirelessly transmit the received user input settings to the controller wireless interface of the HVAC control. The HVAC control is configured to store the received user input settings in the memory of the HVAC control to control the HVAC component. Example methods of controlling an HVAC system are also disclosed.

A method of defrosting an energy recovery ventilator unit. The method comprises defrosting an energy recovery ventilator unit. The method comprises activating a defrost process of an enthalpy-exchange zone of the energy recovery ventilator unit when an air-flow blockage in the enthalpy-exchange zone coincides with a frost threshold in the ambient environment surrounding the energy recovery ventilator unit. The method also comprises terminating the defrost process when a heat transfer efficiency across the enthalpy-exchange zone returns to within 10 percent of a pre-frosting heat transfer efficiency wherein, the heat transfer efficiency is proportional to a temperature difference between an intake air zone of the energy recovery ventilator and a supply air zone of the energy recovery ventilator divided by a temperature difference between an return air zone of the energy recovery ventilator and the intake air zone.

A dehumidifying apparatus controls the amount of refrigerant flowing into a third heat exchanger serving as a condenser, so as to secure the amount of heat required for defrosting.