The disclosed technology includes devices and systems for air handling units used in heating ventilation and air conditioning (HVAC) systems. The disclosed technology can include a unitary heat exchanger structure configured to be positioned in an airflow path of an HVAC system and comprising a refrigerant heat exchanger coil and a hydronic heat exchanger coil. The refrigerant heat exchanger can include a refrigerant flow path configured to (i) receive a refrigerant circulated through the refrigerant heat exchanger coil and (ii) facilitate heat exchange between the refrigerant and air directed across the refrigerant heat exchanger coil. The hydronic heat exchanger coil can include a water flow path configured to (a) receive water circulated through the hydronic heat exchanger coil and (b) facilitate heat exchange between the water and air directed across the hydronic heat exchanger coil.

The disclosed technology includes devices and systems for air handling units used in heating ventilation and air conditioning (HVAC) systems. The disclosed technology can include a unitary heat exchanger structure configured to be positioned in an airflow path of an HVAC system and comprising a refrigerant heat exchanger coil and a hydronic heat exchanger coil. The refrigerant heat exchanger can include a refrigerant flow path configured to (i) receive a refrigerant circulated through the refrigerant heat exchanger coil and (ii) facilitate heat exchange between the refrigerant and air directed across the refrigerant heat exchanger coil. The hydronic heat exchanger coil can include a water flow path configured to (a) receive water circulated through the hydronic heat exchanger coil and (b) facilitate heat exchange between the water and air directed across the hydronic heat exchanger coil.

A method for controlling an air handler includes providing a temperature setpoint to a smart valve in fluid communication with one or more coils of the air handler, providing to the smart valve an air temperature of air conditioned by the air handler, and modulating a valve position of the smart valve using the temperature setpoint, and the air temperature.

A method for controlling an air handler includes providing a temperature setpoint to a smart valve in fluid communication with one or more coils of the air handler, providing to the smart valve an air temperature of air conditioned by the air handler, and modulating a valve position of the smart valve using the temperature setpoint, and the air temperature.

An air handler, comprising: a heating and cooling coil to exchange heat with input air to generate conditioned air; an air diffuser to diffuse the conditioned air to generate diffused air; and an air blower to draw the input air into the air handler via an air inlet, pass the input air over the heating and cooling coil, pass the conditioned air through the diffuser, and expel the diffused air through an air outlet as output air, wherein the air diffuser contains one or more baffles to create two or more air passages that operate to control the expansion and reduction of kinetic energy of the conditioned air to generate the diffused air, a first direction represents a direction of a shortest line between the air blower and the outlet, the air diffuser passes air in a second direction displaced from the first direction by a deflection angle.

An air handler, comprising: a heating and cooling coil to exchange heat with input air to generate conditioned air; an air diffuser to diffuse the conditioned air to generate diffused air; and an air blower to draw the input air into the air handler via an air inlet, pass the input air over the heating and cooling coil, pass the conditioned air through the diffuser, and expel the diffused air through an air outlet as output air, wherein the air diffuser contains one or more baffles to create two or more air passages that operate to control the expansion and reduction of kinetic energy of the conditioned air to generate the diffused air, a first direction represents a direction of a shortest line between the air blower and the outlet, the air diffuser passes air in a second direction displaced from the first direction by a deflection angle.

Some embodiments of the present disclosure provide an air conditioning system. The air conditioning system includes: a housing, having an indoor air supply port; a first heat exchanger, disposed in the housing, an air outlet of the first heat exchanger being communicated with the indoor air supply port; a first air supply mechanism, disposed in the housing, an air outlet of the first air supply mechanism being provided correspondingly to an air inlet of the first heat exchanger; and a plurality of replaceable assemblies, wherein each of the plurality of replaceable assemblies can be assembled in the housing, and the housing is selectively cooperated with one or more of the plurality of replaceable assemblies.

Some embodiments of the present disclosure provide an air conditioning system. The air conditioning system includes: a housing, having an indoor air supply port; a first heat exchanger, disposed in the housing, an air outlet of the first heat exchanger being communicated with the indoor air supply port; a first air supply mechanism, disposed in the housing, an air outlet of the first air supply mechanism being provided correspondingly to an air inlet of the first heat exchanger; and a plurality of replaceable assemblies, wherein each of the plurality of replaceable assemblies can be assembled in the housing, and the housing is selectively cooperated with one or more of the plurality of replaceable assemblies.

An HVAC system is described having components of a variable refrigerant flow (VRF) outdoor compressor unit connected to an indoor fan coil unit. The indoor fan coil unit supplies air to ducts that condition a plurality of zones. Each zone has a volume modulating air damper that can maintain a predetermined volume of air flowing through it. As the dampers for some zones vary between open and close positions, the air pressure in the ducts changes. The volume modulating dampers compensate for these pressure changes, ensuring that only the predetermine volume of air is passing into the zones. By regulating the volume of into each zone, the volume modulating air dampers can restrict the air volume through the fan coil causing the outdoor unit to reduce compressor speed, thereby saving energy.

A heating, ventilation and air conditioning (HVAC) unit can flow conditioned air into an indoor space through a first flow pathway, and receive returned air from the indoor space through a second flow pathway. A sensor module is positioned in the second flow pathway to receive the return air from the indoor space and determine that a quantity of volatile organic compounds (VOCs) in the return air exceeds a threshold VOC quantity. In response, the HVAC unit can flow a quantity of the return air out of the second flow pathway and into the atmosphere, and draw, into the second flow pathway, an equal quantity of air from the atmosphere. The HVAC unit can flow a remainder of the return air and the drawn quantity of air from the atmosphere into the first flow pathway to be conditioned and flowed into the indoor space.