The present invention provides a liquid level sensor and an automatic calibration process which removes the need for prior manual calibration of the liquid level sensor, as this happens dynamically during installation and use of the pump. Further, by frequently monitoring the calibration of the sensor and correcting for long term drift or contamination on the sensing surface, the reliability of the liquid level sensor is considerably better than those of the prior art. By operating a solid state sensor, there are no moving parts in the liquid level sensor described above.

A drain pump clog prediction device predicts the clogging of a drain pump, which is configured to drain water out of a drain pan of an air conditioner. The drain pump clog prediction device includes an obtaining portion that obtains information related to an object in the drain pan and a prediction portion calculates at least one of an object amount, an object size, and an object inflow amount based on information obtained by the obtaining portion and predicts occurrence of the clogging of the drain pump based on at least one of the object amount, the object size, and the object inflow amount.

Embodiments include overflow sensor assemblies for water heaters, HVAC systems, and other devices for which temperature control systems may be used. An example overflow sensor assembly for detecting fluid leaks at a device may include a sensor probe configured to be in electrical communication with a power supply, and a sensor mounting bracket that forms a ground, the sensor mounting bracket configured to attach to a mounting surface on the device and suspend the sensor probe in a condensate drain pan of the device. An overflow detection circuit can be activated when the sensor probe and the sensor mounting bracket come in contact with a condensate fluid.

Controlling heating and cooling in a conditioned space utilizes a fluid circulating in a thermally conductive structure in fluid connection with a hydronic-to-air heat exchanger and a ground heat exchanger. Air is moved past the hydronic-to-air heat exchanger, the air having fresh air supply and stale air exhaust. Sensors located throughout the conditioned space send data to a controller. User input to the controller sets the desired set point temperature and humidity. Based upon the set point temperature and humidity and sensor data, the controller sends signals to various devices to manipulate the flow of the fluid and the air in order to achieve the desired set point temperature and humidity in the conditioned space. The temperature of the fluid is kept less than the dew point at the hydronic-to-air heat exchanger and the temperature of the fluid is kept greater than the dew point at the thermally conductive structure.

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.

This disclosure relates to a method and system for generating operational intelligence for a Heating Ventilation and Air Conditioning (HVAC) device. In one embodiment, the method includes detecting, via a plurality of sensors, a plurality of ambient parameters with respect to a building at periodic intervals; computing, via a processor, a plurality of performance parameters at the periodic intervals based on the plurality of ambient parameters; determining, via the processor, a plurality of operation parameters during an unoccupied period based on the plurality of ambient parameters and the plurality of performance parameters; and dynamically providing, via the processor, a recommendation regarding optimum operation for the HVAC device during the unoccupied period based on the plurality of operation parameters during the unoccupied period.

When an outdoor air handler performs a heating humidifying operation and an air conditioner performs a cooling operation, a control device adjusts at least one of a to-be-supplied air temperature of the outdoor air handler, a to-be-supplied air flow rate of the outdoor air handler, a to-be-supplied water flow rate of the outdoor air handler, and a cooling temperature that is a temperature at an air heat exchanger of the air conditioner. The control device adjusts the to-be-supplied air temperature and the cooling temperature on the basis of dehumidification information, operation information, temperature information, and humidity information. The operation information is information regarding an operating state of the air conditioner.

The electrical connections of a chamber or enclosure for a water tub can be protected through the use of spill element sensors. The spill element sensors can help to disable the delivery of power to the heater of a water tub in the event that the electrical connections become wet.

A direct evaporative cooling system add-on to the existing air conditioning system for more effectively removing the Latent-heat-of-condensation of the refrigerant of the system greatly enhances the EER rating of the system. Upgrading the conventional air-conditioning systems from air cooled refrigerant-condensing-radiator to water-evaporative-cooling via an ADD-ON unit, comprising a reservoir that stores water to be periodically pumped up a pipe under pressure controlled by the electronic controller for timing and quantity. The water is sprinkling uniformly with the help of a plurality of holes in the pipeline wetting the condensing radiator, some of which evaporates cooling the radiator and the excess returning to the reservoir to be recycled over the radiator repeatedly allowing the evaporation and heat exchange process to continue. This cooling effect reduces the pressures required by the compressor at the same time reducing the power drawn from the electrical grid saving money on the electric bill and in turn reducing the carbon foot print created by the use of air conditioning.

An outdoor unit includes a casing having a bottom plate and is configured such that at least a part thereof is made of metal, a compressor provided within the casing to compress a flammable refrigerant, an outdoor heat exchanger provided within the casing to exchange heat between the refrigerant and outside air, and an electric heater provided on an upper surface of the bottom plate. The power consumption of the electric heater is 250 W or less.