A heat exchanger and method which is able to perform in different seasons. The heat exchanger has an upper header and a lower header. Multiple heat pipes extend between the upper header and the lower header, with each of the multiple heat pipes having an evaporator section at one end and a condenser section at the opposite end. The direction of heat flow through the multiple heat pipes is variable depending on ambient air conditions applied to the heat exchanger. A pump is provided in fluid communication with the upper header and the lower header. The pump operates when the heat exchanger is operating in a second mode in which the evaporator section is located above the condenser section, and the pump is disabled when the heat exchanger is operating in a first mode in which the condenser section is located above the evaporator section.

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 phase change material (PCM) module heat exchanger assembly includes a multi-section PCM container rotatingly supported about a center long axis of the multi-section PCM container, or a multi-section PCM container where one or more sections are slidingly mounted to the multi-section PCM container. Each section of a plurality of rotatably or slidingly selected PCM sections is selectably insertable into an air flow. A method of placing one of a group of two or more PCM sections into a building's heating, ventilation, or air conditioning (HVAC) ductwork and a method to harvest heating or cooling capacity for later use are also described.

Transfer of heat energy from within a building to the outside air by means of fans, heat pipes and circulating water in a closed loop system.

Disclosed herein is an air-conditioning apparatus using a heat pipe, wherein the heat exchange and mixed supply of outside air and ventilation air are effectively performed by comparing the state (e.g., temperature, humidity or wet-bulb temperature) of the outside air with the set state (e.g., temperature or humidity) of supply air, and supplying the supply air in a set state (temperature, humidity) through a change in the flow passage of ventilation air and outside air by the selective opening/shutting of dampers, cooling the outside air through latent heat by spraying mist, and cooling and humidifying the supply air. The energy of the air-conditioning apparatus can be reduced because energy efficiency can be improved using the evaporation latent heat of water. The cooling temperature and humidity of the supply air is controlled at a ratio of the ventilation air passing through a cooling coil and the ventilation air passing through a bypass passage. Using a bypass passage, ventilation air can directly move to an air supply block without the intervention of the cooling coil within a heat exchange block through which a ventilation air passes. Operation costs can be reduced and financial gains can be made because an efficient operation is performed.

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.

Systems and methods for controlling conditions in an enclosed space, such as a data center, or for providing cooling to a device, can include using a Liquid-to-Air Membrane Energy Exchanger (LAMEE) as an evaporative cooler. The LAMEE or exchanger can cool water to the outdoor air wet bulb temperature in a cooling system disposed outside of the enclosed space or device. The reduced-temperature water can be delivered to the enclosed space or device or can cool a coolant that is delivered to the enclosed space or device. The air in the enclosed space, or one or more components in the enclosed space, can be cooled by delivering the reduced-temperature water or coolant to the enclosed space, rather than moving the supply air from the enclosed space to the cooling system. In an example, the cooling system can include one or more cooling coils, upstream or downstream of the LAMEE.

Transfer of heat energy from within a building to the outside air by means of fans, heat pipes and circulating water in a closed loop system.

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.

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.