A hybrid system and method for conditioning air for an enclosed space can include a direct cooling system in combination with an indirect cooling system. The hybrid system can use direct cooling when ambient temperature and humidity levels are such that 100% outdoor air can be delivered to the enclosed space. The hybrid system can use indirect cooling when 100% of the return air can be conditioned using an external cooling unit and then returned to the enclosed space as supply air. The external cooling unit can include an evaporative cooler and operate in a dry mode and a wet mode. The external cooling unit can produce a reduced temperature cooling fluid and provide liquid cooling to the air when the system is operating in the indirect mode, and in some cases, in the direct mode. The hybrid system can operate in a mixed mode in which the external cooling unit is off and a mix of return air and outdoor air can be delivered to the enclosed space.

Embodiments of the present disclosure are directed toward a heat exchanger that includes an evaporator coil section disposed at least partially within a first flow structure configured to direct a first flow of air across the evaporator coil section, a condenser coil section fluidly coupled with the evaporator coil section and disposed at least partially within a second flow structure configured to direct a second flow of air across the condenser coil section, and an auxiliary heat exchanger fluidly coupled with the evaporator coil section, where the auxiliary heat exchanger is external to the first flow structure.

A heat pipe heat exchanger is used in combination with a damper assembly to selectively control an amount of heat exchange provided. A divider defines discrete heat pipe plenums and bypass plenums within a duct, and the heat pipe system is configured so that all of the coils of one portion of the heat pipe system are received in the heat pipe plenum(s), while the bypass plenum(s) are free of any coils. The damper assembly includes adjustable heat pipe dampers aligned with the heat pipe plenums and adjustable bypass dampers aligned with the bypass plenums. The damper assembly can include a single actuator that simultaneously opens the heat pipe dampers and closes the bypass dampers and simultaneously closes the heat pipe dampers and opens the bypass dampers.

The invention relates to a recessed hollow profile for mounting to a wall system in a wall of a building, which allows ventilation with efficient decentralised energy recovery. The invention also relates to a system for ventilating a room.

Air conditioning systems and methods for cooling a space that include a chiller, a cooling coil, a heat sink, various water conduits, and a pump. Different modes of operation are used under different conditions and the water is routed differently in different modes. In a first mode, the chiller rejects heat to water returning from the cooling coil, and in a second mode, there are separate loops of chilled and heated water with separate pumps. In a third (economizer) mode of operation, the chiller is off and water from the heat sink is delivered to the cooling coil. Control valves, check valves, or both, are used to direct the flow of water, which are strategically placed in various water conduits.

Described herein is an apparatus and method for avoiding frost and ice buildup in and on vent pipes that transport a stream of gas from the inside to the outside of a building. The apparatus and method comprise a heat-conducting path that extracts heat energy from the stream of gas exiting the vent pipe, and transfers this energy to the frost and ice condensing surfaces at or near the terminus of the vent pipe. The heat-conducting path comprises a heat pipe. In one embodiment the heat-conducting path further comprises a heat exchanger. The passive transfer of heat energy via the heat-conducting path, from the stream of gas to the condensing surfaces of the vent pipe, avoids frost and ice buildup in or around the terminus of the vent pipe.

A liquid to air membrane energy exchanger (LAMEE) can be used as part of a heating and cooling system to transfer heat and moisture between a liquid desiccant and an air stream to condition the temperature and humidity of the air flowing through the LAMEE. The membrane can be a non-porous film having selective permeability for water, but not for other constituents that form the liquid desiccant. The non-porous membrane can allow for use of liquid desiccants, such as glycols, that had been previously determined to be unacceptable or undesirable in these types of applications. In an example, the membrane can be an ion-exchange membrane or pervaporation membrane.

Disclosed is an air-conditioning apparatus using a heat pipe. The state of the outside air is compared with the state of set supply air. The heat exchange and mixed supply of outside air and ventilation air are effectively performed by changing the passage of the ventilation air and the outside air through the selective opening/shutting of dampers, cooling the outside air through latent heat by spraying mist, and by controlling supply air in a set state through the cooling and humidification of the supply air. Accordingly, energy efficiency can be improved and the energy necessary for the air-conditioning apparatus can be reduced using the evaporation latent heat of water. Furthermore, operation costs can be reduced and financial gains can be obtained because an efficient operation can be performed in response to the state of a measured outside air.

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.

An air delivery system may include a housing, a first liquid-to-air membrane energy exchanger (LAMEE), and a desiccant storage tank. The housing includes a supply air channel and an exhaust air channel. The first LAMEE may be an exhaust LAMEE disposed within an exhaust air channel of the housing. The exhaust LAMEE is configured to receive the outside air during a desiccant regeneration mode in order to regenerate desiccant within the exhaust LAMEE. The desiccant storage tank is in communication with the exhaust LAMEE. The exhaust LAMEE is configured to store regenerated desiccant within the desiccant storage tank. The regenerated desiccant within the desiccant storage tank is configured to be tapped during a normal operation mode.