A heat exchanger for exchanging heat between an inside airstream flowing within an interior of a building structure and an outdoor airstream flowing outside of the interior of the building structure includes a heat pipe system comprising a refrigerant. A first heat pipe assembly is installed within the interior of the building structure such that heat is transferrable between the first heat pipe assembly and the inside airstream flowing within the interior of the building structure. A second heat pipe assembly is installed outside of the interior of the building structure such that heat is transferrable between the second heat pipe assembly and the outside airstream flowing outside of the interior of the building structure. The heat pipe system is configured such that the inside airstream remains within the interior of the building structure and the outside airstream remains outside of the interior of the building 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.

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.

A heat exchanger for exchanging heat between first and second duct portions of a ventilation system includes first and second heat pipe portions in the first and second duct portions, respectively. Each heat pipe portion can be a heat pipe subassembly including one or more vertical heat pipes fluidly coupled to top and bottom headers, which are respectively connected to the top and bottom headers of the other subassembly to form a refrigerant loop. One or more flow restrictors can block air flow through a respective section of the first or second duct portion. The blocked section can be operatively aligned with a segment of the respective heat pipe portion along which there is a low probability of refrigerant phase change. Each flow restrictor can be an adjustable damper. The damper(s) can be selectively opened and closed as the ventilation system switches between heating and cooling modes.

An air handling unit (1) for cooling down an indoor airflow (A1) including at least one fan (3) circulating the indoor airflow inside the air handling unit (1) and a first and a second cooling subsystems (5, 15) including a refrigeration apparatus (50, 150) comprising an evaporator (500, 1500) and a condenser (504, 1504), a first water circuit (52, 152) connected to the condenser and comprising at least one outside heat exchanger (520, 1520) exposed to outside air (A5, A15), a second water circuit (56, 156) connected to the evaporator and comprising at least one indoor heat exchanger (560, 1560) exposed to the indoor airflow, water connection means (62, 64, 162, 164) for selectively connecting, depending on a temperature of the outside air.

Embodiments of the present disclosure are directed to an energy recovery system for a heating, ventilation, and/or air conditioning (HVAC) system. The energy recovery system includes a nozzle having a flow passage with an inlet passage and an outlet passage that is narrowed relative to the inlet passage, in which the nozzle is configured to couple to a condenser and receive an air flow into the flow passage from a condenser fan. The energy recovery system further includes a wind turbine disposed within the outlet passage of the flow passage and having a first axis of rotation, and a generator that is external to the nozzle and that includes a shaft with a second axis of rotation. The generator is coupled to the wind turbine, such that the first axis of rotation is aligned with the second axis of rotation.

Several methods and systems for pre-cooling warm air in a cooling system are disclosed. The warm air may be return air, fresh air or a combination of return and fresh air. Condensate from a primary cooling element is applied to the wet side of an air-to-air heat exchanger while the warm air passes through the dry side of the heat exchanger. The warm air is pre-cooled by the transfer of heat from the warm air to the condensate, reducing overall energy consumption in the cooling system.

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.

An example system is configured to control conditions in an enclosed space. The system includes scavenger and process plenums, a liquid-to-air membrane energy exchanger (LAMEE), a first liquid-to-air heat exchanger (LAHX), a second LAHX, and a fluid circuit The scavenger plenum is configured to direct scavenger air from a scavenger inlet to a scavenger outlet. The process plenum is sealed from the scavenger plenum and is configured to direct process air from a process inlet to a process outlet The process inlet receives heated air from the space and the process outlet supplies cooled air to the space. The LAMEE is arranged inside the scavenger plenum. The LAMEE is configured to use the scavenger air to evaporatively cool a first fluid flowing through the LAMEE. The temperature of the first fluid at a LAMEE outlet is lower than the temperature of the first fluid at a LAMEE inlet. The first LAHX is arranged inside the process plenum. The first LAHX is configured to directly and sensibly cool the heated air from the space to a supply air temperature using a second fluid flowing through the first LAHX. The second LAHX is arranged inside the scavenger plenum downstream of the LAMEE. The second LAHX is configured to receive and cool the second fluid heated by the first LAHX using the scavenger air. The fluid circuit transports the first and second fluids among the LAMEE, the first LAHX, and the second LAHX.

An air-conditioning apparatus using a heat pipe is provided, where 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.