A heating and cooling apparatus is disclosed that combines a PTC heating element with a fan, and a combination of a cooling device aided by a thermoelectric cooling device to provide heating, passive air conditioning, and air circulation. The heating and cooling apparatus can include a condensation trap, a collection container, and an ozone generator for collecting and purifying the condensate. In addition, this apparatus provides the additional function of serving as an air purification system operating either in combination with the heating/cooling functions or as an independent air purifier.

A heating and cooling apparatus is disclosed that combines a PTC heating element with a fan, and a combination of a cooling device aided by a thermoelectric cooling device to provide heating, passive air conditioning, and air circulation. The heating and cooling apparatus can include a condensation trap, a collection container, and an ozone generator for collecting and purifying the condensate. In addition, this apparatus provides the additional function of serving as an air purification system operating either in combination with the heating/cooling functions or as an independent air purifier.

Systems and methods are disclosed that calibrate a defrost threshold used to determine when a heating, ventilating, and air conditioning (HVAC) system enters a defrost mode, and, more particularly, determine frost temperature differences used to determine the defrost threshold when the HVAC system is in a stable condition. A frost temperature difference is a difference between an outdoor ambient temperature and a refrigerant temperature. The HVAC system determines that it is in the stable condition by determining that a standard deviation of a current frost temperature difference from a previous frost temperature difference is below a standard deviation threshold. When the HVAC system is in the stable condition, the frost temperature differences are determined, and the defrost threshold is determined from the frost temperature differences.

Systems and methods are disclosed that calibrate a defrost threshold used to determine when a heating, ventilating, and air conditioning (HVAC) system enters a defrost mode, and, more particularly, determine frost temperature differences used to determine the defrost threshold when the HVAC system is in a stable condition. A frost temperature difference is a difference between an outdoor ambient temperature and a refrigerant temperature. The HVAC system determines that it is in the stable condition by determining that a standard deviation of a current frost temperature difference from a previous frost temperature difference is below a standard deviation threshold. When the HVAC system is in the stable condition, the frost temperature differences are determined, and the defrost threshold is determined from the frost temperature differences.

Systems and methods are disclosed that calibrate a defrost threshold used to determine when a heating, ventilating, and air conditioning (HVAC) system enters a defrost mode, and, more particularly, determine frost temperature differences used to determine the defrost threshold when the HVAC system is in a stable condition. A frost temperature difference is a difference between an outdoor ambient temperature and a refrigerant temperature. The HVAC system determines that it is in the stable condition by determining that a standard deviation of a current frost temperature difference from a previous frost temperature difference is below a standard deviation threshold. When the HVAC system is in the stable condition, the frost temperature differences are determined, and the defrost threshold is determined from the frost temperature differences.

Systems and methods are disclosed that calibrate a defrost threshold used to determine when a heating, ventilating, and air conditioning (HVAC) system enters a defrost mode, and, more particularly, determine frost temperature differences used to determine the defrost threshold when the HVAC system is in a stable condition. A frost temperature difference is a difference between an outdoor ambient temperature and a refrigerant temperature. The HVAC system determines that it is in the stable condition by determining that a standard deviation of a current frost temperature difference from a previous frost temperature difference is below a standard deviation threshold. When the HVAC system is in the stable condition, the frost temperature differences are determined, and the defrost threshold is determined from the frost temperature differences.

A method of liquid delivery in an evaporative cooler having an assembly of plates may include delivering liquid from a fill tube to a first trough formed on a first plate of the assembly of plates, the first trough including a first perforation in fluid communication with a second trough formed on a second plate of the assembly of plates, the fill tube configured to deliver the liquid above the first perforation such that an exit point of the fill tube is not submerged in liquid at any point during liquid delivery or operation of the evaporative cooler, draining the liquid from the first trough to the second trough via the first perforation, and filling the second trough to an overflow level before permitting the liquid to exit the second trough via a second perforation, the overflow level defined by a bottom of the second perforation.

An HVACR fan and heater assembly accounts for the cyclonic flow produced by centrifugal blowers by placing a heater vertically and biased towards a side of a fan cabinet in order to increase and balance airflow through the heater, eliminating hot spots and fire risk and improving heater efficiency. A blockoff in the fan cabinet forces airflow within the cabinet to move through the heater. The positioning of the heater may vary depending on the direction of rotation of the centrifugal blower. The fan and heater assembly may further include baffles to direct the airflow from the centrifugal blower.

An air-conditioning unit is provided, comprising: an input vent for receiving return air; an intermediate vent; an output vent; a blower fan proximate to the input vent for moving the return air from the input vent to the intermediate vent; and an air-conditioner coil between the intermediate vent and the output vent including an active portion including one or more operational air-conditioning coils that receive a first portion of the return air from the intermediate vent, for circulating a coolant, condition the first portion of the return air by heat exchange with the coolant to create conditioned air, and pass the conditioned air to the output vent, and an inactive portion that does not circulate coolant and passes a second portion of the return air as unconditioned air to the output vent, wherein the conditioned air and the unconditioned air pass through the output vent as supply air.

An air-conditioning unit is provided, comprising: an input vent for receiving return air; an intermediate vent; an output vent; a blower fan proximate to the input vent for moving the return air from the input vent to the intermediate vent; and an air-conditioner coil between the intermediate vent and the output vent including an active portion including one or more operational air-conditioning coils that receive a first portion of the return air from the intermediate vent, for circulating a coolant, condition the first portion of the return air by heat exchange with the coolant to create conditioned air, and pass the conditioned air to the output vent, and an inactive portion that does not circulate coolant and passes a second portion of the return air as unconditioned air to the output vent, wherein the conditioned air and the unconditioned air pass through the output vent as supply air.