A liquid desiccant air conditioning system comprises an energy exchange unit comprising a sump and a plurality of media pads positioned above the sump, first, second, and third desiccant outlets fluidly connected to the sump, and at least one retractable gate positioned above the sump, configured to partition the sump into at least first and second compartments, wherein the first compartment is fluidly connected to the first desiccant outlet and the second compartment is fluidly connected to the second desiccant outlet, and wherein effective volumes of the first and second compartments can be modified by opening and closing the at least one retractable gate. A method of controlling desiccant circulation in a liquid desiccant air conditioning system is also described.

A liquid desiccant air conditioning system comprises an energy exchange unit comprising a sump and a plurality of media pads positioned above the sump, first, second, and third desiccant outlets fluidly connected to the sump, and at least one retractable gate positioned above the sump, configured to partition the sump into at least first and second compartments, wherein the first compartment is fluidly connected to the first desiccant outlet and the second compartment is fluidly connected to the second desiccant outlet, and wherein effective volumes of the first and second compartments can be modified by opening and closing the at least one retractable gate. A method of controlling desiccant circulation in a liquid desiccant air conditioning system is also described.

An HVAC system is provided. Embodiments of the present disclosure generally relate to heat exchangers having tubing with a reduced diameter compared to traditional systems. In one embodiment, a ducted HVAC system comprises an outdoor heat exchanger with tubing that has an outer diameter of eight millimeters (8 mm) or less and an indoor heat exchanger with tubing that has an outer diameter of nine millimeters (9 mm) or less. Additional systems, devices, and methods are also disclosed.

An HVAC system is provided. Embodiments of the present disclosure generally relate to heat exchangers having tubing with a reduced diameter compared to traditional systems. In one embodiment, a ducted HVAC system comprises an outdoor heat exchanger with tubing that has an outer diameter of eight millimeters (8 mm) or less and an indoor heat exchanger with tubing that has an outer diameter of nine millimeters (9 mm) or less. Additional systems, devices, and methods are also disclosed.

An air handler unit (AHU) in communication with a building automation system (BAS) or through direct programming of one or more smart valves within the AHU operates to meter an amount of water that flows through a coil in the AHU. In one embodiment, the BAS transmits a temperature setpoint signal to the smart valve and allows the smart valve to control its valve position without additional input from the BAS. In another embodiment, the AHU includes a master smart valve and a second valve. The BAS provides the temperature setpoint signal to the master smart valve, which in turn provides another temperature setpoint signal to the second valve. The second valve may take the form of a slave smart valve or a slave non-smart valve.

An air handler unit (AHU) in communication with a building automation system (BAS) or through direct programming of one or more smart valves within the AHU operates to meter an amount of water that flows through a coil in the AHU. In one embodiment, the BAS transmits a temperature setpoint signal to the smart valve and allows the smart valve to control its valve position without additional input from the BAS. In another embodiment, the AHU includes a master smart valve and a second valve. The BAS provides the temperature setpoint signal to the master smart valve, which in turn provides another temperature setpoint signal to the second valve. The second valve may take the form of a slave smart valve or a slave non-smart valve.

Operation switching units, each changing directions of a refrigerant flowing through its associated indoor unit in response to a switch from a cooling operation to a heating operation, or vice versa, are each connected with the associated indoor unit through indoor communication pipes; a gas-liquid separation unit is connected with an outdoor unit through outdoor communication pipes; and the operation switching units are connected with the gas-liquid separation unit through two intermediate communication pipes preinstalled and one intermediate communication pipe newly installed. This provides a simple and cost-effective means for upgrading a preinstalled air conditioner making a switch from cooling to heating, and vice versa, into an air conditioner that can perform a cooling operation and a heating operation in parallel with each other.

Operation switching units, each changing directions of a refrigerant flowing through its associated indoor unit in response to a switch from a cooling operation to a heating operation, or vice versa, are each connected with the associated indoor unit through indoor communication pipes; a gas-liquid separation unit is connected with an outdoor unit through outdoor communication pipes; and the operation switching units are connected with the gas-liquid separation unit through two intermediate communication pipes preinstalled and one intermediate communication pipe newly installed. This provides a simple and cost-effective means for upgrading a preinstalled air conditioner making a switch from cooling to heating, and vice versa, into an air conditioner that can perform a cooling operation and a heating operation in parallel with each other.

A method for heating or cooling rooms in a building with a temperature-controlled system, the temperature-controlled system has a central heater or cooler with a run-around coil system having a supply line and a return line, a central circulation pump for circulating a temperature-control fluid in the run-around coil system, at least two heat exchanger devices that thermally supply one room of the building and are connected to the supply line and the return line of the run-around coil system, one valve with an actuator for each heat exchanger device, one room temperature sensor for each thermally supplied room, and a central open- and closed-loop control unit that is connected to the actuators of the valves and to the room temperature sensors. The method serves to bring about, in the thermally supplied rooms, a temperature transition from a starting state to an end state, with corresponding room temperature setpoint values.

A method for heating or cooling rooms in a building with a temperature-controlled system, the temperature-controlled system has a central heater or cooler with a run-around coil system having a supply line and a return line, a central circulation pump for circulating a temperature-control fluid in the run-around coil system, at least two heat exchanger devices that thermally supply one room of the building and are connected to the supply line and the return line of the run-around coil system, one valve with an actuator for each heat exchanger device, one room temperature sensor for each thermally supplied room, and a central open- and closed-loop control unit that is connected to the actuators of the valves and to the room temperature sensors. The method serves to bring about, in the thermally supplied rooms, a temperature transition from a starting state to an end state, with corresponding room temperature setpoint values.