Abstract: A water heater has one or more heating elements and an internal wall that causes an increased rate of heating within a sub-volume within the water heater tank. Water from the sub-volume is directed to the tank outlet.

Abstract: Disclosed herein are evaporator assemblies for heat pump systems. The evaporator units can comprise a housing defining an interior chamber, an air inlet and an air outlet. The air inlet and the air outlet can form an air flow path through the interior chamber, and an evaporator unit can be positioned within the interior chamber such that the air flow path contacts the evaporator unit. The air inlet having a semi-circular cross section through which air flows into the interior chamber, the semi-circular cross section having a straight edge and a curved edge. A velocity magnitude of the air flowing from the air inlet into contact with the evaporator unit can deviate less than 0.1 m/s from the average air velocity across the surface area of the evaporator.

Abstract: A liquid dosing system is disclosed and can include an inlet conduit and an outlet conduit. The inlet and outlet conduits can each be configured to fluidly communicate a heat exchanger of a water heater. The liquid dosing system can include one or more connector conduits configured to fluidly connect the inlet conduit and the outlet conduit to define a fluid circuit by at least the inlet conduit, the heat exchanger, the outlet conduit, and the one or more connector conduits. The liquid dosing system can include a pump configured to pump water through the fluid circuit, a reservoir configured to store an additive, and a dosing device configured to dispense the additive into the fluid circuit.

Abstract: A system for controlling air flow in an air handling unit having an air mover is provided. The system includes a first and a second sensing device, each receiving a first input indicative of electric power and a second input indicative of properties of air, respectively. The system further includes a processing unit to determine heat generated from a motor of the air mover based on the first input, determine density of air based on the heat generated from the motor based on the second input, and determine an actual air flow rate based on the density of the air, a speed of the motor, and dimensional characteristics of the air handling unit. Further, the speed of the motor is controlled when the actual air flow rate is different from a target air flow rate.

Abstract: The disclosed technology includes systems and methods for controlling an air conditioning system. The method of controlling the air conditioning system can include receiving air temperature data from an air temperature sensor and determining that the air conditioning system should operate in a reheat mode based on the air temperature being less than a threshold air temperature. The method can include outputting a control signal to a first electronic expansion valve to close and thereby prevent refrigerant to flow through an outdoor condenser coil. The method can also include outputting a control signal to a second electronic expansion valve to open and thereby permit refrigerant to flow through a reheat coil.

Abstract: A condenser assembly is disclosed. The condenser assembly can include a condenser coil having a first portion and a second portion. The first portion can be configured to fluidly communicate with a first refrigerant line of a heat pump, and the first portion can have a plurality of windings defining an internal volume. The second portion can be configured to fluidly communicate with a second refrigerant line of the heat pump. The condenser coil can be configured to at least partially insert into an internal volume of a water heater tank.

Abstract: The disclosed technology includes systems and methods for reducing temperature overshoot of a heating, ventilation, and air conditioning (HVAC) system. The disclosed technology can include a thermostat having a temperature sensor and a controller. The controller can be configured to receive temperature data from the temperature sensor, determine whether a time since the heating cycle of the HVAC unit began is greater than or equal to a predetermined amount of time, and determine whether a current temperature is less than or equal to a low threshold temperature, the low threshold temperature being less than a target temperature. If the current temperature is less than or equal to the low threshold temperature, the controller can determine whether a capacity of the HVAC unit at the end of the heating cycle is greater than a threshold capacity and adjust a response setting of the thermostat by a predetermined adjustment amount.

Abstract: Disclosed herein is a flue pipe system comprising a flue pipe, a first electrode, a second electrode, a third electrode, and a voltage supply. The flue pipe can define a fluid flow path through an interior volume of the flue pipe. The voltage supply can be connected to the first electrode, the second electrode, and the third electrode. The voltage supply can form a first electrical circuit comprising the voltage supply, the first electrode, and the third electrode and a second electrical circuit comprising the voltage supply, the second electrode, and the third electrode. The first electrical circuit can form a streamer corona discharge between the first electrode and the third electrode in the interior volume such that the fluid flow path flows therethrough. The second electrical circuit can form a flow of ions between the second electrode and the third electrode along the interior surface of the flue pipe.

Abstract: The disclosed technology includes a device for extending the turndown ratio of a gas-fired burner system. The device can comprise a variable area device configured reduce the amount of fuel and air passed to the burner during low output conditions by adjusting the cross-sectional area of the passage between the blower and the burner. The variable area device can be controlled by an actuator that adjusts the position of the variable area device. The actuator can be manually controlled, mechanically controlled, or electronically controlled.

Abstract: The disclosed technology includes an on-demand water heater which uses an electric heat source to heat the water. The on-demand water heater can have a low fluid capacity heating chamber which has an inlet and an outlet, an electric heat source for heating the water, and a controller to control the electric heat source and maintain the temperature of the water at a predetermined temperature setting. The on-demand water heater can be powered by a direct current power source. The on-demand water heater can also utilize a solar thermal system to provide additional heat to the water.

Abstract: A system and a method for controlling twinned heating appliances are described. The system includes a first heating appliance and a second heating appliance. The first heating appliance includes a first blower and a first wireless communication unit. Further, the second heating appliance is operatively coupled with the first heating appliance as a twinned unit. The second heating appliance includes a second blower and a second wireless communication unit. The system also includes a primary control unit configured to receive speed data indicative of a speed of the first blower and speed data indicative of a speed of the second blower. The primary control unit is further configured to output a blower speed control signal to at least one of the first blower and the second blower to synchronize the first blower and the second blower.

Abstract: The disclosed technology includes systems and methods for detecting an obstructed air filter in a furnace. The disclosed technology can include a method and system that includes an air inlet, an air filter for filtering particles from air passing through the air inlet, an air moving device, a fuel valve, a burner, a pressure sensor, and a controller in communication with the pressure sensor and configured to output an alarm signal when the controller receives differential pressure data from the pressure sensor that indicates that the air filter is obstructed.

Abstract: A tube sheet for a thermal transfer device can include a body having a plurality of apertures that traverse therethrough, where the plurality of apertures are configured to receive a plurality of tubes of the thermal transfer device. The tube sheet can also include an outer perimeter defining the body, where the outer perimeter has at least one first recess feature disposed therein. The at least one first recess feature can have a first shape and a first size, where the first shape is any shape aside from a semi-circle.

Abstract: A managed water system can include a first body of water contained in a vessel. The managed water system can also include at least one sensor device that measures at least one parameter associated with the first body of water. The managed water system can further include a circulation system that circulates the body of water relative to the vessel. The managed water system can also include a controller communicably coupled to the at least one sensor device and the circulation system. The controller can control the circulation system, and receive measurements of the at least one parameter made by the at least one sensor device. The controller can also evaluate the measurements using multiple algorithms, and communicate a result of evaluating the measurements.

Abstract: A water heating system can include a water heater having a tank, and a first temperature sensor disposed toward a top end of the tank to measure a first temperature and a second temperature sensor disposed toward a bottom end of the tank to measure a second temperature. The water heating system can further include a controller communicably coupled to the first temperature sensor and the second temperature sensor, where the controller determines an amount of heated water in the tank based on a plurality of algorithms and measurements made by the first and second temperature sensors. The plurality of algorithms solves for at least one calculated temperature for at least one point between a first location of the first temperature sensor and a second location of the second temperature sensor, where the at least one calculated temperature is used to determine the amount of heated water in the tank.

Abstract: A transfer tube for a thermal transfer device can include at least one wall having an inner surface and an outer surface, where the inner surface forms a cavity, where the at least one wall further has a first end and a second end. The first end can be configured to couple to a terminus of a heat exchanger of the thermal transfer device. The second end can be configured to couple to a collector box of the thermal transfer device. At least a portion of the at least one wall can be disposed in a vestibule of the thermal transfer device. The cavity can be configured to simultaneously receive a first fluid that flows from the first end to the second end and a second fluid that flows from the second end to the first end.

Abstract: A water heating system can include a water heater having a tank, an inlet line, and an outlet line, where the inlet line provides unheated water to the tank, and where the outlet line draws heated water from the tank. The water heating system can also include multiple sensing devices, where each sensing device of the plurality of sensing devices measures a parameter associated with the tank. The water heating system can further include a controller communicably coupled to the plurality of sensing devices, where the controller determines an amount of heated water in the tank based on measurements made by the plurality of sensing devices.

Abstract: A fuel-fired heating appliance comprises a fuel source, an air source, a chamber in which fuel and air mix, a burner downstream from the mixing chamber, an igniter proximate the burner, a heat exchanger, a blower and a flue pipe. An ambient air inlet may be defined by at least one of the outlet end of the blower and the flue pipe extending between the interior of the flue pipe and an area ambient to the flue pipe. A flow rate of combustion gas may be controlled to a level below a steady-state flow rate during appliance warm-up.

Abstract: The disclosed technology includes devices and methods for optimizing refrigerant flow in a heat exchanger. The disclosed technology can include a heat exchanger unit that has a first heat exchanger coil that experiences a first airflow of air passing over the first heat exchanger coil and a second heat exchanger coil that experiences a second airflow of air passing over the second heat exchanger coil. The first airflow can be less than the second air flow. The disclosed technology can include distributor tubes in fluid communication with the heat exchanger coils to direct a flow of refrigerant from an expansion valve to the heat exchanger coils. The first distributor tube can reduce a flow rate of refrigerant to the first heat exchanger coil such that a greater amount of refrigerant is directed to the second heat exchanger coil and refrigerant exits each heat exchanger coil as a superheated vapor.

Abstract: The present disclosure provides a device and a method for detecting leak in a tankless water heater. According to the present disclosure, a leak detection device is disposed on a base of the tankless water heater. The leak detection device includes a leak sensor and at least one absorption arm extending from the leak sensor. The absorption arm wicks water and transports the wicked water towards the leak sensor. The leak sensor generates a signal indicative of leakage in the tankless water heater, in response to sensing wetness.