Desiccant enhanced evaporative cooling systems and methods

A system for conditioning air for an enclosed space, the system comprising:

• a process plenum configured to direct air from a process inlet to a process outlet, the process inlet receiving air at a first temperature and the process outlet supplying air to the space at a second temperature that is lower than the first temperature;
• a first liquid-to-air membrane energy exchanger (LAMEE1) arranged inside the process plenum, the LAMEE1 configured to use a liquid desiccant flowing through the LAMEE1 to reduce the humidity of the air, a first concentration of water in the liquid desiccant at a fluid inlet of the LAMEE1 being lower than a second concentration of water in the liquid desiccant at a fluid outlet of the LAMEE1;
• and
• a second LAMEE (LAMEE2) arranged inside the process plenum downstream of the LAMEE1, the LAMEE2 configured to use water flowing there through to evaporatively cool the air, a temperature of the air at an air outlet of the LAMEE2 being lower than a temperature of the air at an air inlet of the LAMEE2, wherein:
• at least a portion of the water flowing through the LAMEE2 is water removed from the air by the liquid desiccant in the LAMEE1;
• and
• a quantity of the water removed from the air by the liquid desiccant in the LAMEE1 is sufficient as the make-up water for operation of the LAMEE2.

A method of conditioning air for an enclosed space, the method comprising:

• directing air through a process plenum having a plenum inlet and outlet, the air entering the plenum inlet at a first temperature;
• directing the air through a liquid-to-air energy exchanger (LAMEE) arranged inside the plenum, a first moisture content of the air being higher at a LAMEE inlet compared to a second moisture content of the air at a LAMEE outlet;
• directing a desiccant through the LAMEE, the desiccant and air separated by a membrane of the LAMEE, the LAMEE configured to remove water from the air using the desiccant, a first concentration of water in the desiccant being lower at a LAMEE inlet compared to a second concentration of water in the desiccant at a LAMEE outlet, the desiccant at the LAMEE outlet being a dilute desiccant;
• directing the air through a direct evaporative cooler (DEC) arranged inside the process plenum downstream of the LAMEE to cool the air;
• and
• delivering the air to the enclosed space, the air exiting the plenum outlet at a second temperature lower than the first temperature,
• wherein the LAMEE is configured to remove heat from the air using the desiccant as the desiccant and the air are directed through the LAMEE, and wherein a temperature of the desiccant at the LAMEE outlet is higher than a temperature of the desiccant at the LAMEE inlet.

A system for conditioning air for an enclosed space, the system comprising:

• a process plenum having a plenum inlet and outlet, the process plenum configured to direct air in an air flow path from the plenum inlet to the plenum outlet;
• a liquid-to-air membrane energy exchanger (LAMEE) arranged inside the process plenum, the LAMEE comprising a desiccant flow path separated from the air flow path by a membrane, the LAMEE configured to circulate a desiccant through the desiccant flow path and air through the air flow path, a moisture content of the air at a LAMEE outlet being lower than a moisture content of the air at a LAMEE inlet and an enthalpy of the air at the LAMEE outlet being lower than an enthalpy of the air at the LAMEE inlet;
• and
• a direct evaporative cooler (DEC) arranged inside the process plenum downstream of the LAMEE, the DEC configured to evaporatively cool the air, a temperature of the air at a DEC outlet being lower than a temperature of the air at a DEC inlet.