A falling film of liquid desiccant in direct contact with a gas stream is formed, which allows water vapor transfer between a gas stream (air) and the desiccant, enabling dehumidification and/or humidification of air. Thin films are created in one way by a wettable layer that is in contact with a support structure and in another way directly on the support structure. The devices can be installed on an absorber (conditioner) side or a desorber (regenerator) side or both of air conditioning systems; for example, liquid desiccant air conditioning (LDAC) applications.

A falling film of liquid desiccant in direct contact with a gas stream is formed, which allows water vapor transfer between a gas stream (air) and the desiccant, enabling dehumidification and/or humidification of air. Thin films are created in one way by a wettable layer that is in contact with a support structure and in another way directly on the support structure. The devices can be installed on an absorber (conditioner) side or a desorber (regenerator) side or both of air conditioning systems; for example, liquid desiccant air conditioning (LDAC) applications.

A falling film of liquid desiccant in direct contact with a gas stream is formed, which allows water vapor transfer between a gas stream (air) and the desiccant, enabling dehumidification and/or humidification of air. Thin films are created in one way by a wettable layer that is in contact with a support structure and in another way directly on the support structure. The devices can be installed on an absorber (conditioner) side or a desorber (regenerator) side or both of air conditioning systems; for example, liquid desiccant air conditioning (LDAC) applications.

A falling film of liquid desiccant in direct contact with a gas stream is formed, which allows water vapor transfer between a gas stream (air) and the desiccant, enabling dehumidification and/or humidification of air. Thin films are created in one way by a wettable layer that is in contact with a support structure and in another way directly on the support structure. The devices can be installed on an absorber (conditioner) side or a desorber (regenerator) side or both of air conditioning systems; for example, liquid desiccant air conditioning (LDAC) applications.

A conditioning system includes a vapor compression system and a humidity control system. The vapor compression system includes an evaporator, a condenser, a first fan that produces a first airflow across the evaporator toward a conditioned interior space, and a second fan that produces a second airflow from the condenser toward an exterior space. The humidity control system includes a first mass exchange device positioned in the first airflow, a second mass exchange device positioned in the second airflow, and a heat exchanger in fluid communication with both mass exchange devices. The heat exchanger includes a first path and a second path that are thermally coupled and that provide liquid desiccant between the first and second mass exchange devices. The first and second mass exchange devices each include a plurality of cavities configured to permit liquid desiccant to flow therethrough.

Air conditioning units, systems, and methods that control temperature and humidity within a space in a building, for example, using a recovery wheel, a desiccant-based or passive dehumidification wheel, a primary cooling coil; and a secondary direct-expansion refrigeration circuit that includes a secondary circuit compressor, a secondary circuit evaporator coil, and a secondary circuit condenser coil. In various embodiments, the system forms a supply airstream that passes outdoor air first through the recovery wheel, then through the primary cooling coil, then through the secondary circuit evaporator coil, then through the dehumidification wheel, and then to the space. Further, in many embodiments, the system forms an exhaust airstream that passes return air from the space first through the secondary circuit condenser coil, then through the dehumidification wheel, and then through the recovery wheel. In some embodiments, various quantities of heat and moisture are transferred between the two airstreams.

Air conditioning units, systems, and methods that control temperature and humidity within a space in a building, for example, using a recovery wheel, a desiccant-based or passive dehumidification wheel, a primary cooling coil; and a secondary direct-expansion refrigeration circuit that includes a secondary circuit compressor, a secondary circuit evaporator coil, and a secondary circuit condenser coil. In various embodiments, the system forms a supply airstream that passes outdoor air first through the recovery wheel, then through the primary cooling coil, then through the secondary circuit evaporator coil, then through the dehumidification wheel, and then to the space. Further, in many embodiments, the system forms an exhaust airstream that passes return air from the space first through the secondary circuit condenser coil, then through the dehumidification wheel, and then through the recovery wheel. In some embodiments, various quantities of heat and moisture are transferred between the two airstreams.

A heat exchanger for heat exchange between at least two fluids includes a plurality of heat exchange elements each having at least one fluid-guiding path for conducting at least one of the fluids through. The heat exchanger has a cylindrical shape or substantially cylindrical shape with a cylinder axis around which the heat exchange elements are adjacently arranged. At lease a region of each of the heat exchange elements forms an outline structure at least substantially like one of a triangular cylinder, a trapezoidal cylinder, a circle-sector cylinder, and an annulus-sector cylinder. As a result of adjacent arrangement of the heat exchange elements, the heat exchanger or at least a region of the heat exchanger has an outline structure at least substantially like one of a polygonal cylinder, a polygonal hollow cylinder, a circular cylinder, and annular cylinder. The cylindrical shape of the heat exchanger may alternatively be a cone frustum. The heat exchanger may be incorporated into an air device.

A dehumidification system includes a compressor, a primary evaporator, a primary condenser, a secondary evaporator, a secondary condenser, a modulating valve, and an alternate condenser. The secondary evaporator receives an inlet airflow and outputs a first airflow to the primary evaporator. The primary evaporator receives the first airflow and outputs a second airflow to the secondary condenser. The secondary condenser receives the second airflow and outputs a third airflow to the primary condenser. The primary condenser receives the third airflow and outputs a dehumidified airflow. The compressor receives a flow of refrigerant from the primary evaporator and provides the flow of refrigerant to the modulating valve. The modulating valve directs the flow of refrigerant to the primary condenser and to the alternate condenser. The alternate condenser receives a portion of the flow of refrigerant for heat rejection, where the primary condenser receives the remaining portion of the flow of refrigerant.

A dehumidification system includes a compressor, a primary evaporator, a primary condenser, a secondary evaporator, a secondary condenser, a modulating valve, and an alternate condenser. The secondary evaporator receives an inlet airflow and outputs a first airflow to the primary evaporator. The primary evaporator receives the first airflow and outputs a second airflow to the secondary condenser. The secondary condenser receives the second airflow and outputs a third airflow to the primary condenser. The primary condenser receives the third airflow and outputs a dehumidified airflow. The compressor receives a flow of refrigerant from the primary evaporator and provides the flow of refrigerant to the modulating valve. The modulating valve directs the flow of refrigerant to the primary condenser and to the alternate condenser. The alternate condenser receives a portion of the flow of refrigerant for heat rejection, where the primary condenser receives the remaining portion of the flow of refrigerant.