CN110753819A

CN110753819A - Water recovery in desiccant enhanced evaporative cooling systems

Info

Publication number: CN110753819A
Application number: CN201780092237.9A
Authority: CN
Inventors: P·P·莱普德拉
Original assignee: Venmar CES Inc
Current assignee: Nortek Air Solutions Canada Inc
Priority date: 2017-04-18
Filing date: 2017-04-18
Publication date: 2020-02-04
Also published as: US20200063995A1; WO2018191807A1; SG11201909695XA; CN114935182A; EP3612772A4; AU2017410558A1; CA3060332A1; EP3612772A1

Abstract

Systems and methods for conditioning air for an enclosed space using a liquid-to-air membrane energy exchanger (LAMEE) as a pre-dryer to remove moisture from an air stream using a desiccant flowing through the LAMEE are disclosed. The LAMEE can be disposed inside a plenum configured to receive and condition an air flow. The LAMEE can be used in combination with a regeneration system to recover water from the diluted desiccant exiting the LAMEE for use as make-up water for conditioning one or more evaporative coolers in the system. This can reduce or eliminate the external water supply for operation of the one or more evaporative coolers. The conditioning system can operate efficiently using only a portion of the diluted desiccant that is regenerated. In one embodiment, a mixing tank may be used to mix the diluted desiccant (leaving the LAMEE) with the concentrated desiccant stream from regeneration.

Description

Water recovery in desiccant enhanced evaporative cooling systems

Background

There are many applications for which it is important to control the environmental conditions within an enclosed space, such as cooling a data center. Data centers typically include computers and associated components that operate 24 hours a day, 7 days a week. Electrical components in a data center generate a large amount of heat, which needs to be removed from the space. Air conditioning systems in a data center may consume up to 40% of the total energy.

Comfort cooling of residential, commercial and institutional buildings is primarily performed using vapor compression cooling devices. Many process applications, such as data centers, also use mechanical cooling for primary or secondary cooling. In most of these applications, the cooling temperatures required are moderate (e.g., 50F. -85F.; 10℃. -30℃.). Mechanical cooling devices can produce high cooling capacity, operate reliably and can have acceptable costs due to mass production of compressors, heat exchangers and other components. However, these systems require a large amount of high-grade electrical energy to operate. For example, approximately 15% of the total number of domestic electricity production in the united states per year is consumed by air conditioning units. Furthermore, about one third of the peak demand in the hot summer is driven by the air conditioning unit, leading to problems with power grid load and stability. The production of electricity remains carbon intensive, and therefore electrically driven cooling systems can contribute significantly to emissions and global warming.

Thermoelectric power production requires large amounts of water for cooling, and the average water consumption (evaporating water) for combined thermoelectric and hydroelectric production in the united states is about 2 gallons per kWh. The water consumed by the EER 11 air conditioner for electricity production is approximately equal to the water consumed by the evaporative cooling system for producing an equivalent amount of cooling. However, evaporative cooling systems consume far less electricity. Vapor compression also typically requires a synthetic refrigerant that operates at high pressure. The placement of large quantities of cryogen in air conditioning and cooling systems has resulted in safety, health, and environmental concerns. Modern high efficiency refrigerants, such as HFCs, can have high global warming potentials and are being phased out. There is currently no direct replacement refrigerant option with all the desirable properties in terms of efficiency, stability, flammability, toxicity and environmental impact.

Evaporative cooling systems are successfully used in many applications, especially in dry climates. Direct Evaporative Coolers (DEC) can be simple in design and efficient compared to, for example, vapor compression systems. However, conventional DEC may have certain drawbacks. The supply air temperature coming out of the cooler may affect the control and depends on the outdoor air temperature and humidity level. The supply air may be excessively humid. These systems require careful maintenance to ensure that bacteria, algae, fungi and other contaminants do not proliferate in the water system and are transferred into the supply air stream. Because these systems utilize direct contact between the vaporized liquid water and the supply air, entrainment of contaminants into the air stream can occur, which can in turn lead to reduced indoor air quality, odors, and "nausea building syndrome". Furthermore, the accumulation of mineral deposits in the unit and on the evaporation pad can reduce performance and require maintenance.

Indirect evaporative coolers address the humidity issue but typically operate at low wet bulb efficiency. Prior art dew point evaporative coolers can deliver lower cooling temperatures than conventional direct or indirect evaporative systems and can maintain cooling capacity for higher outdoor wet bulb temperatures. However, all evaporative cooling techniques lose cooling performance when the working air humidity rises and cannot be used in humid climates without auxiliary (usually vapor compression) cooling equipment. The water use efficiency of evaporative cooling systems also varies widely depending on system design and control characteristics. Water usage of the evaporative cooler can be a problem, or at least a perceived problem. For example, large-scale data centers may consume large amounts of potable water. Furthermore, for those locations where evaporative cooling works best (dry climates), water demand may not be sustainable.

There remains a need for alternative cooling techniques for comfort conditioning applications that can substantially replace mechanical cooling. The recognition of environmental impacts, including the increase in water consumption, is an urgent challenge for current HVAC cooling equipment.

Drawings

In the drawings, wherein like numerals may describe like parts throughout the different views, the drawings are not necessarily drawn to scale. Like numerals having different letter suffixes may represent similar components, subcomponents of a larger logical or physical system, or similar different instances. The drawings illustrate generally, by way of example, but not by way of limitation, various embodiments described in the present disclosure.

FIG. 1 schematically depicts an exemplary regeneration system for use in a conditioning system having a desiccant dryer LAMEE and an evaporative cooler.

FIG. 2 schematically depicts another exemplary conditioning system including a regeneration system having a Heat Recovery Exchanger (HRE).

FIG. 3 schematically depicts a portion of the regeneration system of FIG. 2.

FIG. 4 schematically depicts another exemplary conditioning system including a regeneration system.

FIG. 5 schematically depicts another example conditioning system, including a centralized regeneration system.

FIG. 6 schematically depicts another exemplary regeneration system for use in a conditioning system.

FIG. 7 is a flow chart depicting a method of operating a conditioning system according to the present disclosure.

Disclosure of Invention

The inventors of the present invention have recognized, among other things, that improving the opportunity to provide cooled performance to an enclosed space by the design of a conditioning system that uses a first liquid-to-air membrane energy exchanger (LAMEE) as a dehumidifier to dry air in an air stream passing through the first LAMEE, thereby reducing the enthalpy and dew point of the air, and then passes the air through a second LAMEE (or another type of evaporative cooler). In one embodiment, the second LAMEE may be used to condition the air flow such that conditioned air may be provided to the enclosed space. In another embodiment, the second LAMEE can be used to cool a water stream flowing through the LAMEE such that the water stream can be routed to a second plenum for cooling the process air stream. The inventors have also recognized the opportunity to use the water removed from the process air stream by the first LAMEE as a source of water supply for an evaporative cooler in a system that includes, for example, a second LAMEE (or other evaporative cooler) downstream to reduce or eliminate the need for an external water supply.

Embodiments according to the present application may include a system for conditioning air for an enclosed space and the system may include a LAMEE disposed inside a plenum configured to direct an air flow path from an inlet to an outlet, and a regeneration system fluidly connected to the LAMEE. The system may further include one or more cooling components disposed inside the plenum. The LAMEE can include a desiccant flow path separated from the air flow path by a membrane and the desiccant can remove water from air in the air flow path. The regeneration system may be configured to separate a portion of the water from the desiccant such that the regeneration system may output a concentrated desiccant stream and a distilled water stream. The concentrated desiccant stream may be returned for recirculation through the LAMEE. In one embodiment, only a portion of the diluted desiccant from the LAMEE is regenerated. The one or more cooling components may utilize at least a portion of the distilled water stream recovered in the regeneration for use as make-up water. This can reduce or eliminate the external water supply for the conditioning system. In one embodiment, the one or more cooling components may include an evaporative cooler disposed within the plenum downstream of the dryer LAMEE. In one embodiment, the downstream evaporative cooler may be a second LAMEE.

The dryer LAMEEs disclosed herein are designed such that the desiccant can remove at least one of moisture and heat from the air stream. Substantially all of the energy removed from the air stream may be transferred to the desiccant. The LAMEE can thus be a two-fluid design, where the first fluid is air and the second fluid is a desiccant.

In one embodiment, the conditioning system may include a liquid-to-liquid heat exchanger (LLHX) or a liquid-to-air heat exchanger (LAHX) configured to cool the desiccant prior to circulating the desiccant through the LAMEE. In one embodiment, the LAHX or LLHX may be configured outside of the plenum. In one embodiment, the LAHX may include evaporative cooling capability and may use water from the regenerator as make-up water. In one embodiment, the LAHX may use an outdoor air cooling desiccant.

In one embodiment, the regeneration system may include a thermally driven regeneration unit. In one embodiment, the regeneration system may use a non-thermal energy source to separate water and desiccant in the desiccant stream.

In one embodiment, the conditioning system may include a single plenum and a single working air stream. The air flow may be hot process air from the enclosed space and the air may be conditioned inside the plenum such that the process air may be returned to the enclosed space at a reduced temperature or humidity. The air stream may be outdoor air, which may be conditioned so that it may be delivered to the enclosed space at a reduced temperature or humidity. The air stream may be a combination of outdoor air and process air.

In one embodiment, the conditioning system may include two plenums and two working air streams. The first plenum may receive a flow of purge air and direct the purge air through the dryer LAMEE and an evaporative cooler downstream of the dryer LAMEE. The evaporative cooler may produce reduced temperature water for cooling. The second plenum may receive a flow of process air from the enclosed space and direct the process air through the LAHX in the second plenum, cooling the process air using the reduced temperature water from the first plenum. The process air may then be returned to the enclosed space.

Embodiments according to the present application may include a system for conditioning air for an enclosed space and the system may include a desiccant dryer LAMEE disposed inside the plenum, the desiccant dryer LAMEE configured for air to pass therethrough and remove water from the air using desiccant flowing therethrough. The desiccant and air may be separated by a membrane in the LAMEE and the LAMEE may assist in the energy exchange between the air and the desiccant such that the desiccant collects substantially all of the energy removed from the air. The conditioning system may further include an evaporative cooler disposed within the plenum downstream of the desiccant dryer LAMEE and configured to circulate at least one of chilled air and water through the evaporative cooler. The conditioning system may further include a fluid loop coupled to the desiccant dryer LAMEE and the evaporative cooler and including a regenerator configured to separate water and desiccant in the desiccant stream. The fluid loop is configured to transport at least a portion of the water removed from the air by the desiccant dryer LAMEE and separated in the regenerator to the evaporative cooler for use as make-up water for operation of the evaporative cooler. In one embodiment, the regenerator comprises a thermal separation unit. In one embodiment, the regenerator includes one or more heat sources to heat the desiccant prior to transferring the desiccant into the thermal separation unit. In one embodiment, the regenerator includes a separation unit driven by a non-thermal energy source.

Embodiments according to the present application may include a method for conditioning air for an enclosed space and may include directing air through a process plenum, directing air through a LAMEE inside the plenum, and directing desiccant through the LAMEE, the desiccant and air separated by a membrane of the LAMEE. The method may include transferring energy in the LAMEE from the desiccant to the air, the energy reduction of the air between the LAMEE inlet and the LAMEE outlet being approximately equal to the energy increase of the desiccant between the LAMEE inlet and the LAMEE outlet. The energy transfer includes removing water from the air using the desiccant such that a first concentration of water in the desiccant at the LAMEE inlet is lower than a second concentration of water in the desiccant at the LAMEE outlet. The method may include regenerating a portion of the diluted desiccant in a regenerator to separate water from the desiccant, directing the concentrated desiccant exiting the regenerator to a fluid loop for a desiccant dryer LAMEE, and directing distilled water from the regenerator to one or more evaporative coolers in a conditioning system. The method may include conditioning the regenerated portion of the diluted desiccant (from the dryer LAMEE). The one or more evaporative coolers in the conditioning system may include an evaporative cooler disposed downstream of the dryer LAMEE and configured to cool the air passing through the plenum. In one embodiment, the downstream evaporative cooler may be a second LAMEE.

The methods disclosed herein can significantly reduce or eliminate the external water supply for regulating the operation of the system. In one embodiment, the enclosed space may be a data center. In one embodiment, the conditioning system disclosed herein may be used in residential and commercial applications.

Embodiments according to the present application may include a system for conditioning air for an enclosed space and the system may include a plurality of conditioning units. Each conditioning unit may include a plenum having a LAMEE and an evaporative cooler downstream of the LAMEE. The system may include a regeneration system fluidly connected to the LAMEE outlet of each conditioning unit such that the regeneration system may regenerate at least a portion of the diluted desiccant from the outlet of the LAMEE of each unit. The system may include a concentrated desiccant storage system for receiving and storing concentrated desiccant from the regenerator system and a distilled water storage system for receiving and storing distilled water from the regenerator system. The concentrated desiccant may be supplied to each conditioning unit as needed for operation of the LAMEE of each conditioning unit. Distilled water may be supplied to the evaporative cooler of each unit as needed for operation of the evaporative cooling components. The system can significantly reduce or eliminate the external water supply for operation of multiple conditioning units.

This summary is intended to provide an overview of the subject matter of the present patent application. It is not intended to provide an exclusive or exhaustive explanation of the invention. The detailed description is included to provide further information about the present patent application.

Detailed Description

The present application relates to systems and methods for conditioning air for an enclosed space, and includes using a liquid-to-air membrane energy exchanger (LAMEE) as a desiccant dryer in combination with a regeneration system to collect water from an air stream for use as makeup water for one or more evaporative coolers in the conditioning system. This can reduce or eliminate the external water supply for regulating the operation of the system and significantly improve water use efficiency as compared to existing designs of evaporative coolers. The desiccant dryer LAMEE may circulate a liquid desiccant, such as lithium chloride, to remove moisture from the air stream passing through the LAMEE. The liquid desiccant and LAMEE are described in more detail below. In one embodiment, the conditioning system may include an evaporative cooler (disposed in the plenum downstream of the desiccant dryer LAMEE) and the evaporative cooler may be configured to provide cooling to an air stream passing through the plenum or to a water stream passing through the evaporative cooler. The evaporative cooler may use water recovered in regeneration from the air stream as make-up water for the evaporative cooler. In one embodiment, the evaporative cooler may be a LAMEE, operating as an evaporative cooler. In such embodiments, the desiccant dryer LAMEE is a first LAMEE and the evaporative cooler LAMEE is a second LAMEE.

In one embodiment, the conditioning system may include a liquid-to-air heat exchanger (LAHX), such as a cooling coil, disposed between the desiccant dryer LAMEE and the evaporative cooler and configured to pre-cool the air stream prior to passing the air stream through the evaporative cooler. In one embodiment, the LAHX/precooler may use water recovered in regeneration from the air stream as a cooling fluid for circulation through the LAHX/precooler.

The desiccant leaving the LAMEE may be a diluted desiccant stream. The conditioning system can operate efficiently using only a portion of the diluted desiccant that passes through the regeneration system. In one embodiment, the desiccant storage tank may be used to mix the diluted desiccant (leaving the LAMEE) with the concentrated desiccant stream from the regeneration system.

In one embodiment, the conditioning system may be configured to condition hot process air (return air) from the enclosed space and return the process air to the enclosed space as cold or reduced temperature process air (supply air). In another embodiment, the conditioning system may condition outdoor air and deliver the conditioned air to the enclosed space. In yet another embodiment, the conditioning system may condition a combination of process air and outdoor (make-up) air for delivery to the enclosed space.

A liquid-to-air membrane energy exchanger (LAMEE) may be used as part of a conditioning system to transfer heat and moisture between a liquid and an air stream, both flowing through the LAMEE to condition the temperature and humidity of the air or to reduce the temperature of the liquid. In one embodiment, the membrane in the LAMEE may be a non-porous membrane that is selectively permeable to water but not to other components that may be present in the liquid. Many different types of liquids may be used in combination with the non-porous membrane, including, for example, water, liquid desiccants, glycols. In one embodiment, the membranes in the LAMEE may be semi-permeable or vapor permeable, and generally any substance in the gas phase is able to pass through the membrane and generally any substance in the liquid phase is not able to pass through the membrane. In one embodiment, the membrane in the LAMEE may be microporous, such that one or more gases can pass through the membrane. In one embodiment, the membrane may be a selectively permeable membrane such that certain components are able to pass through the membrane but others are not. It is appreciated that any type of membrane suitable for use with an evaporative cooler LAMEE or a desiccant dryer LAMEE may be used with the LAMEEs included in the conditioning systems disclosed herein.

In one embodiment, the LAMEE can use a flexible polymeric membrane that is vapor permeable to separate air and water. Relative to other systems/devices, the water flow and air flow through the LAMEE may not be limited by problems such as droplet carryover at high face velocities. Further, the LAMEE can be operated at water flow rates that enable transport of thermal energy into a cooler similar to a cooling tower, and the elevated inlet water temperature can increase the evaporative cooling power of the LAMEE.

The desiccant dryer LAMEE may circulate any type of liquid desiccant suitable for removing moisture from air. In one embodiment, the cooling fluid is a liquid desiccant that is a high concentration salt solution. The presence of salt may disinfect the cooling fluid to prevent microbial growth. In addition, the desiccant salt may affect the vapor pressure of the solution and allow the cooling fluid to release or absorb moisture from the air. Examples of salt-based desiccants useful herein include lithium chloride, magnesium chloride, calcium chloride, lithium bromide, lithium iodide, potassium fluoride, zinc bromide, zinc iodide, calcium bromide, sodium iodide, and sodium bromide. In one embodiment, the liquid desiccant may include an acetate salt, such as, but not limited to, aqueous potassium acetate and aqueous sodium acetate.

In one embodiment, the liquid desiccant may comprise ethylene glycol or an aqueous solution of ethylene glycol. Glycols may be unsuitable for use in a direct contact exchanger because ethylene glycol can evaporate into the air stream. Glycol-based liquid desiccants can be used here with non-porous membranes, since the membranes prevent the transfer of glycol into the air. In one embodiment, the liquid desiccant may comprise a glycol or ethylene glycol based solution, such as triethylene glycol and propylene glycol, which is non-toxic, compatible with most metals, and relatively low cost. The glycols may be strongly hygroscopic at higher concentrations. For example, a 95% solution of triethylene glycol has comparable drying/dehumidification potential as lithium chloride near saturation. Triethylene glycol and tripropylene glycol can have low vapor pressures, but can be expensive. Less expensive and higher vapor pressure glycols such as ethylene glycol, diethylene glycol, propylene glycol, and dipropylene glycol may be used herein.

Other examples of liquid desiccants that may be used in the desiccant dryer LAMEE described herein include, but are not limited to, hygroscopic polyol-based solutions, sulfuric acid, and phosphoric acid. Glycerol is one example of a hygroscopic polyol useful herein. It is appreciated that a mixture of desiccants may be used as the liquid desiccant in the desiccant dryer LAMEE described herein. In addition to the desiccants listed above, the liquid desiccants may include, but are not limited to, acetate solutions, halide salt solutions, hygroscopic polyol based solutions, ethylene glycol based solutions, sulfuric acid solutions, phosphoric acid solutions, and any combination thereof.

In one embodiment, the conditioning system may include a regeneration system configured to increase the concentration of the liquid desiccant exiting the desiccant dryer LAMEE prior to recirculating the liquid desiccant through the desiccant dryer LAMEE. Systems and methods are disclosed for recovering water from an air stream (which is absorbed by liquid desiccant in a desiccant dryer LAMEE) and using the recovered water as make-up water for one or more cooling devices in the system, including, for example, an evaporative cooler located downstream of the desiccant dryer LAMEE. The systems and methods disclosed herein can eliminate or significantly reduce the external water consumption of an evaporative cooler.

In one embodiment, the LAMEE can circulate an evaporative cooling fluid through the LAMEE and the LAMEE can operate as an evaporative cooler, rejecting heat using cooling potential in both air and a cooling fluid (e.g., water). As described above, the evaporative cooler located downstream of the desiccant dryer LAMEE may be an evaporative cooler LAMEE. In one embodiment where the LAMEE is an evaporative cooler, the water or both the air and the water may be cooled to a temperature near the inlet air Wet Bulb (WB) temperature as the air flows through the LAMEE. Due to the evaporative cooling process in the LAMEE, the temperature of the water at the outlet of the LAMEE may be less than the temperature of the water at the inlet, or the temperature of the water may not be changed, but the air may be cooled. Other types of evaporative cooling fluids, including those listed above, may be used in combination with or as an alternative to water.

LAMEEs can provide advantages over conventional cooling systems such as cooling towers. The membrane separation layer in the LAMEE can reduce maintenance, can eliminate the need for chemical treatment, and can reduce the possibility of contaminant transfer to the liquid loop. The use of LAMEEs with upstream and/or downstream cooling coils (or other LAHX) can result in lower temperatures and higher cooling potential of the water exiting the LAMEE. Various configurations of conditioning systems with one or more LAMEEs are described herein and can improve performance in many climates.

FIG. 1 depicts an exemplary regeneration system 11, which may be part of a conditioning system 10 for conditioning air for delivery to an enclosed space. The conditioning system 10 may be used in commercial and industrial applications as well as residential applications. The conditioning system 10 may be used to cool air that is hot because of the conditions in the surrounding equipment and enclosed space. The conditioning system 10 may be used for comfort cooling in residential and commercial applications. The conditioning system 10 may receive hot process air from the enclosed space and condition the process air so that it may be returned to the enclosed space as supply air of reduced temperature or reduced humidity. The conditioning system 10 may receive outdoor air and condition the outdoor air prior to delivering the outdoor air to the enclosed space. In other embodiments, the conditioning system 10 may receive a mixture or combination of outdoor air and process air.

In one embodiment, where the conditioning system 10 receives process air from an enclosed space, the conditioning system 10 may sometimes be referred to as a 100% recirculation system, which generally means that the air within the enclosed space is recirculated through the conditioning system 10 in the following successive cycles: cooled by the system 10 to a target supply air temperature, supplied to the space, heated by components in the space (e.g., computers, servers, and other electronic equipment), and returned to the system 10 for cooling. Although not shown or described in detail, in such embodiments, the conditioning system 10 may include a make-up air unit or system to continuously or periodically refresh the air within the space to meet ventilation requirements.

The conditioning system 10 may include a desiccant dryer LAMEE6 disposed in the plenum 4 and an Evaporative Cooler (EC)8 disposed in the plenum 4 downstream of the LAMEE 6. The plenum 4 may be configured to receive an airflow through the plenum inlet 12 and release the airflow through the plenum outlet 14. Dampers 18, 20 may be associated with and generally juxtaposed with inlet 12 and outlet 14, respectively. Although not shown in fig. 1, the fan may be disposed inside the plenum 4 upstream of the desiccant dryer LAMEE6 or in some other location. In one embodiment, the conditioning system 10 may be configured to receive a flow of scavenging air if the system 10 has two working airflows (and two plenums), or a return airflow (from the enclosure) if the system 10 has one working airflow (and one process plenum). In another embodiment, the air entering the process plenum 4 may be outdoor air. In yet another embodiment, the air entering the process plenum 4 may be a mixture of outdoor air and process air from the enclosed space.

The regeneration system 11 may be configured for use with various conditioning systems including a combination of a desiccant dryer LAMEE6 and an evaporative cooler 8 downstream of the dryer LAMEE 6; such a regulation system may comprise further components not shown in fig. 1. The conditioning system 10 may include one or more features, such as dampers, that may assist in the bypass of the desiccant dryer LAMEE 6.

The evaporative cooler 8 may be any type of evaporative cooler suitable for use inside the process plenum 4 to cool an air stream or to cool an evaporative fluid circulating through the evaporative cooler 8 so that the fluid may be used to condition the separated air stream in the second plenum. In one embodiment, the evaporative cooler 8 may be a LAMEE, also referred to herein as an evaporative cooler LAMEE. Evaporative cooler LAMEEs are non-contact evaporative coolers because the membrane in the LAMEE separates the evaporative fluid (water) and air and maintains the separation between them. In such embodiments where the evaporative cooler 8 is a LAMEE, the desiccant dryer LAMEE6 may also be referred to herein as a first LAMEE6 and the evaporative cooler LAMEE 8 may also be referred to herein as a second LAMEE 8. In other embodiments, the evaporative cooler 8 may include, but is not limited to, a wetted media or a spray atomizer system, both of which are embodiments of a direct contact evaporative cooler in that the evaporative fluid (water) directly contacts the air to cool the air. In another embodiment, evaporative cooler 8 may include a wet deck or other flooded fill material (similar to that which may be used in cooling towers), these are additional embodiments of direct contact coolers, as the evaporative fluid directly contacts the air.

The conditioning system 10 may circulate a liquid desiccant through the LAMEE6 to reduce the humidity level of the air stream entering the plenum 4 before passing the air stream through the evaporative cooler 8. After circulating through the LAMEE6, the liquid desiccant may be diluted due to absorbed moisture from the air. A reduction in the concentration of desiccant may thereby reduce the drying capacity of the LAMEE 6. The regeneration system 11 may include a regenerator 52 that may be configured to regenerate the liquid desiccant prior to recycling the liquid desiccant back through the LAMEE 6.

After the liquid desiccant exits the LAMEE6 at the LAMEE outlet 28, the liquid desiccant may be discharged into a desiccant canister 26 configured for storage of the liquid desiccant. The desiccant may be transported from the desiccant tank 26 to the regenerator 52 and the liquid to air heat exchanger (LAHX) or the liquid to liquid heat exchanger (LLHX)32 via the pump 42. The LAHX or LLHX 32 can be configured to reduce the temperature of the desiccant prior to passing the desiccant into the LAMEE6 at the LAMEE inlet 34. The LAHX or LLHX 32 and the regenerator 52, in combination, can therefore reduce the temperature of the liquid desiccant and increase the concentration of the liquid desiccant before circulating the desiccant through the LAMEE 6. Both capabilities may be important so that the desiccant effectively removes moisture from the air stream passing through the LAMEE 6. The regulating valve 68 can control and vary the distribution of the desiccant from the tank 26 to the regenerator 52 and LAHX or LLHX 32, as further described below.

The regeneration system 11 may include a first desiccant loop 24 and a portion of a second desiccant loop 66 fluidly connected to the first desiccant loop 24. The LAHX or LLHX 32 can be part of the first desiccant loop 24. The tank 26 may be part of the first desiccant loop 24 and the second desiccant loop 66. The regenerator 52 may be part of a second desiccant loop 66. The regenerator 52 may include an energy input to assist in the separation of the water and desiccant. For example, such energy input may include, but is not limited to, heat, mechanical power, electrical power, or a combination thereof.

The desiccant exiting the canister 26 may be transported to the regenerator 52 through the second desiccant loop 66 and enter the regenerator 52 at an inlet 70. The regenerator 52 may separate a portion of the water from the desiccant such that a first exit stream 71 exiting the regenerator 52 at a first outlet 72 may be concentrated desiccant and a second exit stream 73 exiting the regenerator 52 at a second outlet 74 may be distilled water. (concentration levels of desiccant C1-C3 are described below.) the first exit stream 71 may be part of the second desiccant loop 66. In one embodiment, the first exit stream 71 may be transported back to the tank 26 via a pump 76.

The second exit stream 73 (distilled water) may be transported via pump 78 to the tank 36 for the evaporative cooler 8 and used in the first water loop 30 for the evaporative cooler 8. Thus, water in the air stream passing through the plenum 4 may be absorbed by the desiccant in the desiccant dryer LAMEE6 separate from the desiccant in the regenerator 52 and then used as make-up water for the evaporative cooler 8. The evaporative cooler 8 may still be connected to an external water supply, which is shown in fig. 5 as an external water supply to the tank 36. External water may be provided to the evaporative cooler 8, as required; however, the use of the recovered water from the desiccant by the evaporative cooler 8 can result in a significant reduction or elimination of water for the operation of the evaporative cooler 8. In other embodiments, the water in the second exit stream 73 may be used by more than one cooling unit in the conditioning system.

The diluted desiccant exiting the LAMEE6 at the LAMEE outlet 28 may have a first desiccant concentration C1. The diluted desiccant may be mixed with the existing desiccant in the canister 26 such that the concentration of desiccant in the canister 26 may be at a second concentration C2 that is greater than the first concentration C1. In one embodiment, the difference in concentration between the first concentration C1 and the second concentration C2 may be small. The desiccant at the second concentration C2 may be regenerated in the regenerator 52 such that the third concentration C3 of the desiccant in the first exit stream 71 may be substantially greater than the second concentration C2. The concentrated desiccant in the first exit stream 71 (at the third concentration C3) may then be mixed with the diluted desiccant exiting the LAMEE6 (at the first concentration C1) and with the desiccant already in the tank 26 to increase the second concentration C2 of the mixed desiccant. Likewise, the second concentration C2 in the tank 26 may depend on the concentrations C1, C3, and the volume/flow of each, as well as the volume of desiccant in the tank 26.

Even though the mixed desiccant in the tank 26 may be at a second concentration C2 that is higher than the first concentration C1 of diluted desiccant exiting the LAMEE6, the mixed desiccant may be referred to herein as "diluted desiccant" relative to the concentrated desiccant exiting the regenerator 52 at concentration C3. Similarly, the desiccant entering the LAMEE may be referred to herein as "concentrated desiccant" relative to the diluted desiccant exiting the LAMEE6, even though the concentration C2 of the desiccant entering the LAMEE may be less than the concentration C3 of the desiccant exiting the regenerator 52.

Fig. 1 shows an exemplary design for a regeneration system 11 in which diluted desiccant exiting the LAMEE6 may be mixed with concentrated desiccant from a regenerator 52, and a portion of the desiccant exiting the tank 26 may be circulated back through the LAMEE6 and a portion may be regenerated. The valve 68 may control the distribution of the desiccant exiting the tank 26 to the LAMEE6 and to the regeneration system 11. In other embodiments, the conditioning system 10 may be configured such that all or a portion of the diluted desiccant exiting the LAMEE6 may be transported directly to the regenerator 52, rather than mixing the diluted desiccant in the tank 26 with the concentrated desiccant returning from the regenerator 52. This is shown in fig. 6 and described below.

The dehumidification capacity of the LAMEE6 can depend on the flow rate, temperature, and concentration of the liquid desiccant passing through the LAMEE 6. In one embodiment, the conditioning system 10 may operate using a setpoint temperature and setpoint concentration of the liquid desiccant at the LAMEE inlet 34; the flow of desiccant through the LAMEE6 can be substantially constant. The load on the LAMEE6 may change as the conditions of the airflow through the plenum 4 change. If the humidity of the air stream increases, the load on the LAMEE6 may increase. As a result, the liquid desiccant exiting the LAMEE6 at the outlet 28 may require more regeneration than if the LAMEE6 received a low humidity air stream. The regeneration system 11 may be configured such that the flow of liquid desiccant to the regenerator 52 may be increased by the regulating valve 68 when additional regeneration of the desiccant is required. In one embodiment, the regulator valve 68 may be controlled by the system controller 50 described below.

An increase in the flow of liquid desiccant to the regenerator 52 may result in an increase in the flow of concentrated liquid desiccant returned to the tank 26 at the concentration C3. An increased amount of concentrated liquid desiccant may be mixed with the liquid desiccant in the tank 26 to increase the concentration C2 of the liquid desiccant that is transported back to the LAMEE6 (after passing through the LAHX or LLHX 32). The flow of desiccant to the regenerator 52 may be controlled such that the concentration C2 may be at or near the setpoint concentration for the LAMEE6 at the LAMEE inlet 34. In one embodiment, the concentration C2 may vary (up or down), depending at least in part on the load of the system (i.e., outdoor air conditions).

Alternatively or in conjunction with the use of a regeneration system, the concentration of the liquid desiccant in the first desiccant loop 24 may be increased by introducing concentrated desiccant into the desiccant canister 26. This may be done intermittently or throughout the operation of the system 10 as desired.

The system 10 may be designed such that only one portion of the desiccant is regenerated in the regenerator 52. Thus, in one embodiment, the system 10 may continue to operate with high efficiency without requiring all of the desiccant to flow through the regenerator 52. The valve 68 may direct all or a portion of the desiccant from the tank 26 directly back to the LAMEE 6. This is partly a result of the mixing in the tank 26 of the concentrated desiccant from the regeneration system with the diluted desiccant from the LAMEE 6. This is also a result of this design of LAMEE6 operating at high flow rates of liquid desiccant through the LAMEE 6. Because the flow rate of the liquid desiccant through the LAMEE6 is high, the reduction in the concentration of desiccant in the desiccant flow between the inlet 34 and the outlet 28 of the LAMEE6 is small, as compared to if the desiccant flow rate was low. Likewise, in one embodiment, only a small portion of the desiccant from the tank 26 may be diverted for regeneration.

The LAMEE6 is configured such that the desiccant removes at least one of water and heat from the air stream. It is appreciated that if the desiccant only removes water from the air (i.e., the air maintains a substantially constant temperature between the LAMEE inlet and the LAMEE outlet), the temperature of the desiccant at the outlet of the LAMEE6 may still be higher than the temperature of the desiccant at the inlet of the LAMEE 6. The temperature increase of the desiccant is due to the latent heat of condensation of moisture from the air.

This design of the LAMEE6 allows the desiccant to not only remove water from the air stream, but the desiccant is also able to remove heat from the air stream. The LAMEE6 can be configured such that substantially all of the energy removed from the air stream is transferred to the desiccant stream. In other words, the energy reduction of the air in the air stream between the LAMEE inlet and the LAMEE outlet may be approximately equal to the energy increase of the liquid desiccant in the desiccant stream between the LAMEE inlet and the LAMEE outlet. It is appreciated that there may be some losses inherent in the system and that 100% of the energy removed from the air stream cannot all be transferred to the desiccant stream. For purposes herein, the term "substantially all energy" or "all energy" recognizes and takes into account such losses in the system. Similarly, for purposes herein, a system that is not 100% efficient and has some losses is recognized and taken into account with respect to the "approximately equal" reduction in energy of the air relative to the energy of the desiccant. The LAMEE6 can be configured such that a single fluid (desiccant) can be used to remove both heat and water from the air. Thus, the LAMEE6 can be a two-fluid design, the first fluid being an air stream and the second fluid being a desiccant. Additional fluids are not included to reduce the energy of the air, and a single desiccant flow in the LAMEE6 can adequately remove heat and water from the air stream passing through it. The heat from the air stream may be primarily latent heat, although some sensible heat may also be removed from the air by the desiccant. Because the flow rate of the liquid desiccant through the LAMEE6 is high, the temperature increase of the desiccant flow between the inlet 34 and the outlet 28 of the LAMEE6 is small, as compared to if the flow rate is low.

In one embodiment, the flow of the liquid desiccant to the LAHX or LLHX 32 may be relatively constant and the flow of the liquid desiccant through the regulating valve 68 may be variable. It is appreciated that the flow of liquid desiccant to the LAHX or LLHX 32 may also be variable in other embodiments.

The regenerator 52 may include any type of device capable of separating liquid water from liquid desiccant. For example, the regenerator 52 may include, but is not limited to, vacuum multi-effect membrane distillation (VMEMD), electrodialysis, reverse osmosis filtration, gas fired boiler with condenser, vacuum assisted generator, multi-stage flash, membrane distillation, and combinations thereof. The type of energy input to regenerator 52 may include, for example, electrical power, mechanical power, or heat. The type of energy input depends on the technology used for regeneration of the liquid desiccant. Although regenerator 52 is shown in fig. 1 as a single unit, regenerator 52 may represent more than one unit operation. For example, the regeneration system 11 may include a heat recovery unit upstream of the regeneration unit. This is further described below with reference to fig. 2 and 4.

The system 10 may include any type of device suitable for cooling a liquid desiccant. For example, the system 10 may include, but is not limited to, polymer fluid coolers (with evaporative cooling capability), plate heat exchangers, and combinations thereof. In one embodiment, the LAHX or LLHX 32 may provide air cooling to the liquid desiccant using outdoor air outside of the conditioning system 10. In another embodiment, the LAHX or LLHX 32 may provide liquid cooling to the liquid desiccant using another cooling fluid. In one embodiment, the LAHX or LLHX 32 may be located outside of the process plenum 4 or other components of the conditioning system 10. In one embodiment, the LAHX or LLHX 32 can be supplemented by an evaporative cooler for the desired use, depending on outdoor air conditions. For example, the LAHX may be supplemented with evaporative cooling sprays so that the tubes may be water sprayed to enhance cooling. In one embodiment, the evaporative cooler LAHX 32 may use the water recovered from the regeneration system 11 as make-up water for the LAHX 32.

The design of the regeneration system 11 in combination with the desiccant dryer LAMEE6 can help regulate the operation of the system 10 with little to no external water consumption. The LAMEE6 can remove water from the air stream and use that water (separated from the desiccant for regeneration of the desiccant) as a make-up water supply for conditioning one or more evaporative coolers in the system 10. The recovered water may be stored in a tank 36 and may be used as needed. Operation of an evaporative cooler, such as evaporative cooler 8, may generally require a significant amount of water. The conditioning system 10 with the regeneration system 11 can eliminate or significantly reduce the external water required to operate the system 10. In one embodiment, the system 10 may be substantially water neutral. In one embodiment, the system 10 may include an external water supply as a backup in the event additional water is needed.

In one embodiment, the LAHX or LLHX 32 may require make-up water in one embodiment, in which the LAHX or LLHX 32 includes evaporative cooling for the desired use. Evaporative cooling may be utilized when the outdoor air is at a high dry bulb temperature and the air cooling of the liquid desiccant is insufficient to meet the desiccant for delivery to the LAMEE 6. It is appreciated that the recovered water from the regenerator system 11 may be sufficient in some cases to provide make-up water requirements for the evaporative cooler 8 as well as the evaporative cooler LAHX 32.

The design of the regeneration system 11 in combination with the desiccant dryer LAMEE6 may also improve the operation of the evaporative cooler 8, as water may be collected directly from the atmosphere. Likewise, the water recovered from the liquid desiccant in the regenerator 52 may be high quality water, which may be desirable for many cooling applications, including evaporative coolers. Such high quality water may increase the life of the medium in the evaporative cooler 8 and may reduce the required maintenance of the cooler. Conversely, if the water supplied to the evaporative cooler 8 is potable water from a well or surface water source, then in some cases mineral clogging or scaling may occur, which may require the system 10 to include a management of mineral concentration or other water treatment unit. In general, the design described herein can reduce or eliminate the overall water consumption of the conditioning system 10, as well as improve the operation of the evaporative cooler 8.

The system controller 50 may manage the operation of the conditioning system 10, including the regeneration system 11. The system controller 50 may include hardware, software, and combinations thereof to implement the functionality attributed to the controllers herein. The system controller 50 may be an analog, digital, or combined analog and digital controller, including many components. By way of example, the controller 50 may include an ICB, PCB, processor, data storage device, switch, relay, and the like. Embodiments of the processor may include any one or more of a microprocessor, controller, Digital Signal Processor (DSP), Application Specific Integrated Circuit (ASIC), Field Programmable Gate Array (FPGA), or equivalent discrete or integrated logic circuitry. The storage device is described in certain embodiments as a computer-readable storage medium. In certain embodiments, the storage devices comprise temporary memory, meaning that the primary purpose of one or more storage devices is not long-term storage. The storage device is described in some embodiments as volatile memory, meaning that the storage device does not retain stored content when the computer is turned off. Examples of volatile memory include Random Access Memory (RAM), Dynamic Random Access Memory (DRAM), Static Random Access Memory (SRAM), and other forms of volatile memory known in the art. The data storage device may be used to store program instructions for execution by the processor of controller 50. The memory device is used, for example, as an embodiment by software, applications, algorithms running on the controller 150 and/or executed by the controller 50. The storage devices may include short-term and/or long-term memory, and may be volatile and/or nonvolatile. Examples of non-volatile storage elements include magnetic hard disks, optical disks, floppy disks, flash memory, or forms of electrically programmable memory (EPROM) or Electrically Erasable and Programmable (EEPROM) memory.

The system controller 50 may be configured to communicate with the conditioning system 10 and its components via various wired or wireless communication techniques and components using various public and/or private standards and/or protocols. For example, some type of power and/or communication network may be employed to facilitate communication and control between the controller 50 and the conditioning system 10. In one embodiment, system controller 50 may communicate with conditioning system 10 via a private or public Local Area Network (LAN), which may include wired and/or wireless elements that function according to one or more standards and/or via one or more propagation media. In one embodiment, the system 10 may be configured for wireless communication using a wireless communication protocol according to one or another of the 802.11 or bluetooth specification sets, or proprietary. Data transmitted to and from components of system 10, including controller 50, may be formatted according to a variety of different communication protocols. For example, all or a portion of the communication may be through a packet-based Internet Protocol (IP) network that communicates data over, for example, Category 5 ethernet cable in transmission control protocol/internet protocol (TCP/IP) packets.

The system controller 50 may include one or more programs, circuits, algorithms, or other mechanisms for controlling the operation of the conditioning system 10. For example, the system controller 50 may be configured to control the valve 68 to adjust and vary, as needed, the volume of desiccant diverted to the regeneration system. In one embodiment, the system controller 50 may control components to maintain a low humidity level or low temperature of the supply air. Such control may be based on variable sensible and latent loads in the enclosed space. The controller 50 may be responsive to changing outdoor air conditions or changing requirements for ventilation to the enclosed space. In one embodiment, the system controller 50 may control or vary the amount of outdoor air added to the plenum 4.

FIG. 2 depicts another exemplary conditioning system 100, including a regeneration system 111. The conditioning system 100 may include many of the components and functions of the conditioning system 10 of fig. 1. The conditioning system 100 may include a heat recovery heat exchanger (HRE)180 in combination with a regenerator or regeneration unit 152, both of which may be part of the regeneration system 111. The HRE180 is not required to regulate operation of the system 100, but, as described below, can assist in improved efficiency and performance of the regeneration system 111. The second desiccant loop 166 may include the HRE180 and the regenerator 152.

As stated above with reference to fig. 1, the regenerator 152 may comprise any type of device capable of separating water from a desiccant. One embodiment, described below and illustrated in fig. 3, uses a thermally driven separation process. The regenerator 152 may include a heat source 151 configured to heat the desiccant to evaporate water in the desiccant. (see fig. 3.) the HRE180 may preheat the desiccant before it is heated by the heat source 151. Given the inclusion of the HRE180, less heat may be required from the heat source 151 to evaporate water in the desiccant stream, as compared to if the regenerator 152 is operated without the HRE 180.

In fig. 2, the desiccant from the tank 126 passes through the HRE180 before passing into the regenerator 152. Conversely, the regenerator 52 in fig. 1 is shown receiving desiccant directly from the tank 26 at an inlet 70. The HRE180 may be configured to exchange heat between the concentrated desiccant exiting the regenerator 152 and the desiccant entering the regenerator 152. The desiccant may enter the HRE180 at inlet 181 and temperature T1. The desiccant may exit the HRE180 at an outlet 182 and at a temperature T2, which may be greater than the temperature T1. The concentrated desiccant may enter the HRE180 at inlet 183 and temperature T3. The concentrated desiccant may exit the HRE180 at an outlet 184 and at a temperature T4, which may be less than the temperature T3. In other words, the HRE180 may be configured for the concentrated desiccant from the regenerator 152 to reject heat to the mixed desiccant from the tank 126. As a result, the mixed desiccant exiting the HRE180 at the outlet 182 may be preheated prior to entering the regenerator 152.

The concentrated desiccant exiting the HRE180 at the outlet 184 may be transported to the tank 126 for storage and for recycling back to the LAMEE 106. It may be advantageous for the concentrated desiccant to be at a reduced temperature T4 to reduce or maintain the temperature of the desiccant in the tank 126. The temperature of the desiccant in the tank 126 may directly affect the amount of heat that must be rejected from the desiccant in the heat exchanger 132. Thus, the HRE180 may serve two benefits: heating the mixed desiccant prior to regeneration and cooling the concentrated desiccant prior to circulation through the heat exchanger 132 and LAMEE 106.

A heat source 151 is shown generally as being provided to a regenerator 152. Fig. 3 illustrates an exemplary heat source and desiccant path through the HRE180 and then through the one or more heat sources 151 before entering the regenerator 152.

As described above, the conditioning system 100 may receive a flow of scavenging air or a flow of process air, or a combination thereof. In one embodiment, the conditioning system 100 may include two working air streams (and two plenums) or one working air stream and one plenum. In such embodiments using two working air streams, outdoor (scavenge) air may be used to produce chilled water in the Evaporative Cooler (EC)108 (disposed in the first plenum 104) and such chilled water may be used to provide cooling to the process air stream passing through the second (process air) plenum.

The following numbers are exemplary conditions for the conditioning system 100, based on a patterned conditioning system.

The outdoor air enters the plenum 104 at a dry bulb temperature of 90 degrees Fahrenheit (32.2 degrees Celsius), a wet bulb temperature of 85 degrees Fahrenheit (29.4 degrees Celsius), a moisture content of 25.2g/kg, and a flow rate of 30,000 SCFM. The liquid desiccant enters the desiccant dryer LAMEE 106 at an inlet 134 at a temperature of 34 degrees celsius, a concentration of 38% lithium chloride (LiCl), and a flow rate of 250 GPM.

After leaving the desiccant dryer LAMEE 106, the sweep air was at a dry bulb temperature of 35.6 degrees celsius and a moisture content of 15.2 g/kg. The moisture removal rate was 613.4 kg/hour (0.170kg/s) and the total cooling was 377 kW.

The desiccant exits the LAMEE 106 at the outlet 128 at a temperature of 40.4 degrees celsius and the concentration C1 is 37.7% LiCl. The diluted desiccant enters the canister 126 at a concentration C1 and mixes with the desiccant in the canister 126. The concentration of mixed desiccant C2 exiting the tank 126 was 38.0% LiCl and the mixed desiccant was transported from the tank 126 through the pump 142 at a flow rate of 275 GPM. The regulator valve 168 may divert 25GPM or 1.58L/s of desiccant to HRE 180. The remaining 250GPM (15.8L/s) of the desiccant may flow to the heat exchanger 132 (and then to the LAMEE 106). In this embodiment, nine percent (9%) of the desiccant exiting the tank 126 is diverted to the regenerator 152. As described above, in one embodiment, the flow to the heat exchanger 132 may be substantially constant and the flow to the HRE180 may be variable depending on, for example, the regenerative load.

The heat exchanger 132 may reduce the temperature of the desiccant in the first desiccant loop 124 such that the temperature of the desiccant at the inlet 134 is 34 degrees celsius.

The desiccant entering the HRE180 at inlet 181 (at concentration C2) is heated in the HRE180 from a temperature T1(40.6 degrees Celsius) to a temperature T2(55.3 degrees Celsius) at outlet 182. The increased temperature desiccant then enters the regenerator 152 at inlet 153. As a result of the separation process occurring in the regenerator 152 (see fig. 3 and description below), the desiccant exits the regenerator 152 at the outlet 155 at a concentration C3 equal to 41.7% LiCl and a temperature T3(60.0 degrees celsius) greater than the temperature T2. The concentrated desiccant stream (C3) may be transported to the tank 126 via the pump 176. The temperature T1(40.6 degrees celsius) at the inlet 181 of the HRE180 may be slightly higher than the temperature at the LAMEE outlet 128 (40.4 degrees celsius) because the desiccant from the outlet 128 mixes with the hot concentrated desiccant returning to the tank 126 at the temperature T4(43.5 degrees celsius). The values provided above for temperatures T1-T4 are exemplary based on a patterned system. It is appreciated that the temperature may depend at least in part on the concentration C2, the concentration C1, and the concentration target for the inlet 134 to the LAMEE 106.

The collected water may exit the regenerator 152 at outlet 174 at a rate of 0.17L/s or 2.7 GPM. The water may be transported to the tank 136 via the pump 178 to be used by the evaporative cooler 108 as make-up water.

The concentrated desiccant at concentration C3 may exit the HRE180 at outlet 184 and at temperature T4(43.5 degrees celsius) and may then be transferred back to the tank 126 at a rate of 1.41L/s or 22.3 GPM. The concentrated desiccant at 41.7% LiCl (C3) was mixed with the diluted desiccant at 37.7% LiCl (C1) to produce a concentration C2 at 38.0% LiCl.

These are exemplary values. It is appreciated that the capacity of the heat exchanger 132, the HRE180, and the regenerator 152 may be dependent on load variations on the desiccant dryer LAMEE 106. The operation of the system 100 in one embodiment may be controlled by a system controller 150 that may operate similarly to the system controller 50 described above. As described above with reference to fig. 1, the regulating valve 168 may be used to control the flow of desiccant from the tank 126 through the regenerator and thereby control the concentration C2, including maintaining the concentration C2 at or near the target concentration for the inlet 134.

FIG. 3 depicts a portion of the regeneration system 111 of FIG. 2 including an HRE180, a regeneration unit 152, and one or more heat sources 151. As described above with reference to fig. 2, the HRE180 may receive the mixed desiccant (from the canister 136) at the inlet 181 (at an increased temperature) and the concentrated desiccant (from the regenerator 152) at the inlet 183. The concentrated increased temperature desiccant (C3, T3) exiting the regenerator 152 may transfer heat to the mixed desiccant (C2, T1) from the tank 136. The concentrated desiccant (C3, T4) at the outlet 184 may flow back to the tank 136. The mixed desiccant (C2, T2) at the outlet 182 may flow to the regeneration unit 152.

In one embodiment, the one or more heat sources 151 may include a solar collector 185 and a supplemental heater 187. The mixed desiccant may flow through the one or more solar collectors 185 before passing into the regeneration unit 152, and the one or more solar collectors 185 may further increase the temperature of the desiccant using energy from the sun 186 before the desiccant flows through the regenerator 152. In one embodiment, the two collectors 185 of FIG. 3 may be evacuated tube solar collectors that may circulate the desiccant through the tubes prior to transferring the desiccant to the regenerator 152. In another embodiment, the solar collector may be a flat panel design.

The regeneration system 111 may include an auxiliary heater 187 located between the solar collector 185 and the regeneration unit 152. The auxiliary heater 187 may use various sources to increase the temperature of the desiccant before it enters the regeneration unit 152. Such sources may include, but are not limited to, combustion of gases, waste heat, and fuels. The supplemental heater 187 may be operated intermittently, depending at least in part on the load on the regeneration unit 152 and the heating (if any) provided by the solar collector 185.

The solar collector 185 and the heater 187 may increase the temperature of the desiccant prior to separating the water and the desiccant in the regeneration unit 152. The vapor pressure may increase rapidly as the desiccant temperature increases, resulting in a large flux of water vapor out of the desiccant. It is not required that regeneration system 111 include both tube collector 185 and supplemental heater 187. In other embodiments, a tube collector 185 or a supplemental heater 187 may be used. In other embodiments, other forms of heating may be used for heat source 151 in conjunction with tube collector 185 and supplemental heater 187 or as an alternative to tube collector 185 and supplemental heater 187.

The desiccant leaving the supplemental heater 187 may enter the regeneration unit 152 as hot desiccant. In one embodiment, the temperature at the inlet of the regenerator 152 may be approximately 80 degrees celsius. In order for the regenerator 152 to be effective, the desiccant stream must be hot enough to evaporate water from the desiccant stream. In one embodiment, the regeneration unit 152 may separate water and desiccant using a membrane distillation separation process. In such embodiments, and as described in detail below, the regeneration unit 152 may include an evaporation section 188 and a concentration section 179.

The evaporator end 188 can have a plurality of channels 189 and a corresponding membrane 190 for each of the channels 189. The desiccant may be directed into each of the channels and may flow inside the channels 189 and down the channels 189. The material forming the membrane may be permeable to water but impermeable to the desiccant. Each membrane 190 may contact the exterior of its corresponding channel such that the membrane 190 creates a seal around the channel 189. As the hot desiccant travels down the channels 189, water may be released from the desiccant as water vapor. Water vapor may permeate through membrane 190 and thus permeate out of channels 189. The desiccant may be maintained in liquid form, may be contained within the channels 189 by the membranes 190 and may travel down the channels to the manifold 191. The manifold 191 may transport the increased concentration of desiccant (C3) out of the regenerator 152 and to the HRE 180. As discussed above, the increased concentration of desiccant may be cooled in the HRE180 before being transported to the canister 136.

Water vapor from the evaporation section 188 may travel to a concentration section 179, which may include a plurality of channels 192 that function as cooling channels 192. Although not shown in fig. 3, the regeneration unit 152 may include an inlet to and an outlet from the passage 192 for the source of air used to provide cooling to the water vapor. The water vapor may pass outside of the channels 192 and the water vapor may condense on the surface of the cooling channels 192 as a result of the cooling fluid flowing inside the channels 192. The cooling fluid may be any fluid (liquid or gas) suitable for cooling the surrounding material such that water vapor condenses on the exterior surfaces forming the channels 192. In one embodiment, the cooling fluid may be air. The air may come from any source at conditions favorable for providing air cooling to the water vapor. Examples of air sources may include, but are not limited to, outdoor air or exhaust air from the outlet of the heat exchanger 132. In one embodiment, a regeneration unit similar to unit 152 may be used in a conditioning system for a process air stream and such a conditioning system may include an exhaust air stream including an exhaust LAMEE. In such embodiments, the exhaust air from the exhaust LAMEE outlet may be used as the air source for the air cooling passage 192. The air circulating through the channels 192 may be relatively humid as long as the air is still relatively cool. In one embodiment, the cooling fluid may be water.

The condensate (distilled water) may be collected by gravity by a water collection tank 193 at the bottom of the regeneration unit 152. Tank 193 can be at the bottom of regeneration unit 152 or connected to outlet 174 of regeneration unit 152 and distilled water can be transported from tank 193 to other parts of the conditioning system, such as one or more evaporative coolers. In one embodiment, as shown in fig. 3, the water may be delivered to a tank 136 for use as make-up water for the evaporative cooler 108. This can reduce or eliminate the external water supply for operating the conditioning system 100.

FIG. 3 illustrates one embodiment of a regeneration unit, which may include a thermally driven separation process. It is appreciated that other types of regeneration may be used to separate the desiccant from the water, including but not limited to those listed above with reference to fig. 1.

FIG. 4 depicts another exemplary conditioning system 200, including a regeneration system 211. FIG. 4 illustrates an exemplary heat source that may be used to drive the operation of the regenerator 252 in the regeneration system 211. FIG. 4 also illustrates an exemplary design having a concentrated desiccant storage tank 294 and a distilled water storage tank 296, described further below.

The desiccant dryer LAMEE206 is shown in fig. 4 and, in one embodiment, may be used in combination with an evaporative cooler located downstream of the LAMEE206, as described above with reference to fig. 1 and 2. In other embodiments, other coolers may be included in the system 200, such as a liquid-to-air heat exchanger (LAHX) located between the desiccant dryer LAMEE and the evaporative cooler.

As described above with reference to fig. 2 and 3, the desiccant from the LAMEE206 may be directly heated (using any type of heat source) prior to circulating the desiccant through the regeneration unit 152. In another embodiment, the desiccant may be heated using a heat transfer fluid. The heat transfer fluid may be heated and then transfer heat to the desiccant, which is shown in fig. 4.

The conditioning system 200 may include a heating fluid circuit 298 for circulating a heating fluid through the regenerator 252 of the regeneration system 211. Heating fluid loop 298 may include solar thermal array 285 and auxiliary heater 287. In one embodiment, the solar thermal array 285 may be configured similarly to the solar collector 185 of fig. 3. The solar thermal array 285 may include first and second solar devices 285a, 285b, which may include flat plate collectors or evacuated tube collectors, for example. The sub-heater 287 may be similar to the sub-heater 187 of fig. 3.

The regenerator or regeneration unit 252 may be similar to the unit 152 shown in fig. 3, but may further include a liquid-to-liquid heat exchanger (LLHX) contained within the heating fluid loop 298. The LLHX can be inside the regenerator unit 252 upstream of the evaporation section (see section 188 of fig. 3) or the LLHX can be outside the regeneration unit 252 and upstream of the desiccant inlet to the regeneration unit. Instead of heating the desiccant using the solar thermal array 285 or the supplemental heater 287, the solar thermal array 285 or the supplemental heater 287 can heat the heating fluid and then the heating fluid can transfer heat to the desiccant in the LLHX. The hot desiccant may then be processed through a regenerator 252, as described above with reference to fig. 3.

In one embodiment, the heating fluid may be a glycol solution. The heating fluid may be any type of liquid suitable for transferring heat to the desiccant such that the desiccant is heated prior to passing through the evaporator section in the regenerator 252. Other examples include, but are not limited to, water and oil.

One or both of solar thermal array 285 and heater 287 may be intermittent or continuous heat sources. In one embodiment, the supplemental heater 287 may use waste heat from another source within the system 200. In another embodiment, the supplemental heater 287 may use a gas as a heat source.

In one embodiment, the regenerator system 211 may operate and separate water from the desiccant when heat (solar heat, waste heat, etc.) is available to operate the regenerator. The concentrated desiccant from the regenerator 252 may be transported to a concentrated desiccant storage tank 294. Similarly, distilled water from the regenerator 252 may be transported to a distilled water storage tank 296. The concentrated desiccant may be pulled from the storage tank 294 and supplied to the desiccant tank 226 via a pump 295 as needed (as shown in fig. 4). Alternatively, the concentrated desiccant may be transported directly to the heat exchanger 232 or to the LAMEE 206. Similarly, distilled water may be pulled from the storage tank 296 and supplied to one or more evaporative coolers in the conditioning system 200 via pump 297, as needed. One or both of the

tanks

294, 296 may be included in other conditioning systems described herein and shown in fig. 1 and 2.

The regeneration system 211 may operate similarly to the

regeneration systems

11, 111 of fig. 1 and 2, respectively, and a portion of the desiccant from the tank 226 may be transported to the regenerator 252 for regeneration. A larger portion of the desiccant from the tank 226 may be transported to the heat exchanger 232 and returned to the LAMEE 206. Instead of a regulator valve (see valves 68, 168) as shown in fig. 1 and 2, the system 200 may include two pumps fluidly connected to the desiccant tank 226. The first pump 242 may deliver desiccant from the tank 226 to the LAMEE206 and the second pump 243 may deliver desiccant from the tank 226 to the regenerator 252. This two-pump design of fig. 4 may also be used in the designs of fig. 1 and 2. Similarly, the regulator valve design of fig. 1 and 2 may also be used in the design of fig. 4. The system controller may control the flow of desiccant to the LAMEE206 and the flow of desiccant to the regenerator 252. One or both of such flows may be constant or variable.

Although a heat recovery heat exchanger is not shown in fig. 4, it is appreciated that an HRE may be included in the conditioning system 200 upstream of the regenerator 252 and operate similarly to the HRE180 of fig. 2.

Fig. 5 depicts an exemplary system 300 that may include a plurality of desiccant dryer LAMEEs 306. Each of the

desiccant dryers LAMEEs

306a, 306b, 306c may be part of a

conditioning unit

301a, 301b, 301c, respectively, those may include an air plenum housing the desiccant dryers LAMEE and an Evaporative Cooler (EC) downstream of the desiccant dryers LAMEE. Each

conditioning unit

301a, 301b, 301c may thus function similarly to any of the conditioning systems described herein, including the

conditioning systems

10, 100 of fig. 1 and 2, respectively.

Instead of each

conditioning unit

301a, 301b, 301c having its own regeneration system, the system 300 may include a centralized regenerator apparatus 303 having the ability to regenerate one portion of the desiccant from each of the

LAMEEs

306a, 306b, 306 c. The regenerator device 303 may include some or all of the components described herein, such as a heat recovery heat exchanger, a heating fluid, a solar thermal array, and so forth. For simplicity, these additional components are not specifically shown in fig. 5, but rather the heat input to the device 303 is schematically shown generally.

Each

conditioning unit

301a, 301b, 301c can have a

desiccant loop

366a, 366b, 366c fluidly connected to a

tank

326a, 326b, 326c and to the centralized regenerator apparatus 303. The desiccant in the

desiccant loops

366a, 366b, 366C may be at a concentration C2 at the inlet 370 to the regenerator apparatus 303. The desiccant may be regenerated in the device 303 (as described above) such that the first outlet stream 371 exiting the device 303 at outlet 372 may be concentrated desiccant at concentration C3 and the second outlet stream 373 exiting the device 303 at outlet 374 may be distilled water. The concentrated desiccant may be transported to a concentrated desiccant storage tank 394 and distilled water may be transported to a distilled water storage tank 396.

As described above with reference to fig. 4, the concentrated desiccant from the storage tank 394 may be transported back to each of the units 301 through the centralized output flow 367 from the tank 394. Stream 367 may be fluidly connected to an input stream forming part of the desiccant loop 366 for each of the units 301. In one embodiment, the concentrated desiccant at concentration C3 may be transferred back to the tank 326 for each conditioning unit 301. Distilled water from the storage tank 396 may be supplied to each conditioning unit 301 via a stream of water 375 from the storage tank 396. As described above, distilled water may be used as make-up water for one or more evaporative coolers in conditioning unit 301. The system 300 may further include an external water supply of potable/treated water, which may be conveyed through a water stream 377 fluidly connected to a water stream 375. Such external water may be used as a backup for the conditioning system 300 if and when the distilled water is insufficient as make-up water for the conditioning unit 301.

In one embodiment, conditioning unit 301 may be used to provide cooling for a data center, and conditioning unit 301 may be located on the roof of the data center. The embodiment of fig. 5 shows three regulating units 301. It is appreciated that the system 300 may include any number of adjustment units. Depending on the number of conditioning units 301, more than one regenerator device 303 may be used in combination with the conditioning units 301. In one embodiment, the regenerator apparatus 303 may be housed within a desiccant processing chamber, which may be housed within the data center or external to the data center.

As shown in fig. 5, each conditioning unit 301 may receive concentrated desiccant from a tank 394 and distilled water from a tank 396. In another embodiment, each conditioning unit 301 may have a dedicated desiccant tank and a dedicated water tank.

FIG. 6 illustrates an example conditioning system 400, and the example conditioning system 400 may be similar to the

conditioning systems

10, 100, 200, but may include alternative designs for the fluid loop for regeneration. Only one portion of the system 400 is shown in fig. 6 for simplicity and it is appreciated that additional components may be included. For example, only a portion of the system enclosure 402 and plenum 404 are shown in fig. 6, but it is appreciated that the plenum 404 may include some or all of the additional components shown and described above with reference to fig. 1, 2, and 4.

The desiccant dryer LAMEE 406 may operate similarly to the desiccant dryer LAMEE described above. The diluted desiccant exiting the desiccant dryer LAMEE 406 at outlet 428 may split into two flow paths-a first flow path to the tank 426 or a second flow path directly to the regenerator 452 (via the desiccant loop 466). The regenerator 452 may operate similarly to the regenerators described above. The desiccant entering the regenerator 452 at the inlet 470 may be at a first concentration C1. The concentrated desiccant exiting the regenerator 452 at outlet 472 may be at a third concentration C3 and may be transported to the tank 426 to mix with the desiccant already in the tank 426. Likewise, the desiccant in the canister 426 may be at a second concentration C2 that is greater than the first concentration C1 and less than the third concentration C3.

In contrast to the design shown in fig. 1, 2 and 4, instead of the diluted desiccant (at concentration C1) being mixed with the desiccant in a tank and then flowing to the regenerator (at second concentration C2), the diluted desiccant leaving the LAMEE 406 in fig. 6 is transported directly to the regenerator 452 (via pump 467) at the first concentration C1. All of the desiccant leaving the tank 426 at the second concentration C2 is circulated through the heat exchanger 432 and back through the LAMEE 406, rather than selectively directing a portion of the desiccant at the second concentration C2 to the regenerator 452. Thus, the split in the desiccant flow path in the design of fig. 6 is at the outlet 428 of the LAMEE 406, rather than at the outlet of the tank 426.

A pump 467 is shown in the desiccant loop 466 and is an embodiment of a means for regulating or controlling the flow of diluted desiccant to the regenerator 452. As described above with reference to other exemplary conditioning systems, in one embodiment, only a portion of the diluted desiccant that typically exits the LAMEE 406 during operation of the system is sent to the regenerator 452. The amount of desiccant transported to the regenerator 452 may be variable and a percentage of the desiccant at the outlet 428 may be directed to the regenerator and the remaining percentage of the desiccant at the outlet 428 may be directed to the tank 426. Such percentages may depend in part on the load of the adjustment system 400.

Fig. 7 illustrates an exemplary method 700 for conditioning air for delivery to an enclosed space in accordance with the exemplary conditioning system described above. The method 700 can reduce or eliminate the external water supply to the conditioning system. The method 700 may include directing air through a desiccant dryer LAMEE disposed in the process plenum at 702 and directing the concentrated desiccant into and through the LAMEE to remove moisture from the air at 704. In one embodiment, the LAMEE at 702 can be further configured such that the desiccant can also remove heat from the air such that the temperature of the desiccant at the LAMEE outlet is higher than the temperature of the desiccant at the LAMEE inlet. The air flow through the LAMEE may be outdoor air, hot supply air from an enclosed space, or a combination thereof. The conditioning system may include one working air stream (via the process plenum) or two working air streams: a first air stream containing scavenging air and a second air stream containing process air.

The method 700 may include, at 706, regenerating the diluted desiccant exiting the LAMEE to separate water from the desiccant before recycling the desiccant back through the LAMEE. In one embodiment, only a portion of the desiccant exiting the LAMEE may be regenerated. The regeneration step may result in a concentrated desiccant output stream and a distilled water output stream.

The method 700 may include directing the concentrated desiccant from the regenerator back to the fluid loop for the desiccant dryer LAMEE at 708. In one embodiment, the concentrated desiccant may be directed to a desiccant canister that may also receive diluted desiccant exiting the LAMEE. The diluted desiccant and the concentrated desiccant may be mixed such that the desiccant in the canister may be at a higher concentration than the diluted desiccant exiting the LAMEE and lower than the concentrated desiccant exiting the regenerator. The desiccant canister may be contained within a desiccant fluid loop that passes through the LAMEE.

The method 700 may include directing, at 710, distilled water from a regenerator to one or more evaporative coolers in a conditioning system. In one embodiment, the one or more evaporative coolers may include an evaporative cooler disposed in the plenum downstream of the desiccant dryer LAMEE, and the recovered water from the regenerator may be used as make-up water for operation of the evaporative cooler. In one embodiment, where the conditioning system uses two working air streams and two plenums, the evaporative cooler in the first plenum may be used to cool the water passing therethrough and the cooled water may be routed to the LAHX in the second plenum to cool the process air stream passing through the second plenum. In one embodiment, the one or more evaporative coolers may include a LAHX in the desiccant loop, which may be configured to cool the desiccant prior to flowing the desiccant through the desiccant dryer LAMEE. The LAHX may be inside or outside the plenum housing the desiccant dryer LAMEE. The LAHX may include evaporative cooling capacity and may use recovered water from the regenerator as make-up water for operation of the evaporative cooler LAHX. The use of recovered water from regeneration by one or more evaporative coolers in the system can significantly reduce or eliminate the external water supply used to regulate the operation of the system.

It is appreciated that the method 700 for conditioning air may include other steps not included in fig. 7. Such additional steps may include, but are not limited to, directing the air through a precooler or LAHX disposed in the process plenum downstream of the LAMEE and upstream of the evaporative cooler. In one embodiment, directing air through the LAMEE in 702 may include mixing process air with outdoor air upstream of the LAMEE to create a mixed air flow through the process plenum. In one embodiment, method 700 may include removing a portion of the air in the mixed stream at a location downstream of the precooler and upstream of the evaporative cooler to create an exhaust air stream and cool the cooling fluid circulating through the precooler with the exhaust air stream. In one embodiment, the method 700 may include directing cooled water from the evaporative cooler in the first plenum to the LAHX in the second plenum to cool the process air passing through the second plenum.

The foregoing detailed description includes references to the accompanying drawings, which form a part hereof. The drawings show, by way of illustration, specific embodiments in which the invention may be practiced. These embodiments are also referred to herein as "examples". Such embodiments may include elements in addition to those shown or described. However, the inventors also contemplate embodiments in which only those elements shown or described are provided. Moreover, the inventors also contemplate embodiments (or one or more aspects thereof) using any combination or arrangement of those elements shown or described, with respect to a particular embodiment (or one or more aspects thereof), or with respect to other embodiments (or one or more aspects thereof) shown or described herein.

All patent publications, patents, and patent documents mentioned in this document are incorporated by reference herein, in their entirety, as if individually incorporated by reference. In the event of inconsistent usages between this document and those documents incorporated by reference, the usage in the incorporated references should be considered supplementary to that of this document; for irreconcilable inconsistencies, the usage in this document takes precedence.

In this document, the terms "a" or "an" are used, as is common in patent documents, to include one or more than one, independent of any other instances or uses of "at least one" or "one or more". In this document, the term "or" is used to refer to a non-exclusive or, such that "a or B" includes "a but not B," "B but not a" and "a and B," unless otherwise indicated. In this document, the terms "including" and "in which" are used as the plain-english equivalents of the respective terms "comprising" and "wherein". Furthermore, in the claims that follow, the terms "comprise" and "comprise" are open-ended, i.e., a system, apparatus, article, or method that comprises elements in addition to those listed after such term in a claim is still considered to fall within the scope of the claims. Furthermore, in the following claims, the terms "first," "second," and "third," etc. are used merely as labels, and are not intended to impose numerical requirements on their objects.

The method embodiments described herein may be at least partially machine or computer implemented. Certain embodiments may include a computer-readable medium or machine-readable medium encoded with instructions operable to configure an electronic device for performing a method as described in the embodiments above. Implementations of such methods may include code, such as microcode, assembly language code, a higher level language code, or the like. Such code may include computer readable instructions for performing various methods. The code may form part of a computer program product. Further, the code may be tangibly stored on one or more tangible computer-readable media, which may be volatile or non-volatile, such as during execution or at other times. Examples of such tangible computer-readable media may include, but are not limited to, hard disks, removable magnetic disks, removable optical disks (e.g., compact disks and digital video disks), magnetic cassettes, memory cards or sticks, Random Access Memories (RAMs), Read Only Memories (ROMs), and the like.

Embodiments as described herein may include or may operate on logical or numerous components, modules, or mechanisms. A module may be hardware, software, or firmware communicatively coupled to one or more processors to perform the operations described herein. A module may be a hardware module, and as such a module may be considered a tangible entity capable of performing specified operations and may be configured or arranged in a certain manner. In one embodiment, the loops may be arranged in a specified manner as modules (e.g., inside or outside an entity such as other circuitry). In one embodiment, all or a portion of one or more computer systems (e.g., a stand-alone, client or server computer system) or one or more hardware processors may be configured by firmware or software (e.g., instructions, application portions, or applications) as modules that operate to perform specified operations. In one embodiment, the software may reside on a machine-readable medium. In one embodiment, the software, when executed by the underlying hardware of the module, causes the hardware to perform the specified operations. Accordingly, the term hardware module is understood to encompass a tangible entity, be it a physically constructed entity, be it specially configured (e.g., hardwired) or temporarily (e.g., momentarily) configured (e.g., programmed) to operate in a specified manner or to perform part or all of any of the operations described herein. In view of the embodiments in which the modules are temporarily configured, each of the modules need not be instantiated at any one time in time. For example, if the module includes a multipurpose hardware processor configured using software; the multipurpose hardware processor may be configured at different times as separate and distinct modules. The software may configure the hardware processor accordingly, e.g., to constitute a particular module at one time and to constitute another module at another time. The modules may also be software or firmware modules that operate to perform the methods described herein.

The above description is intended to be illustrative and not restrictive. For example, the embodiments described above (or one or more aspects thereof) may be used in combination with each other. Other embodiments may be used, for example, by one skilled in the art upon reading the above description. Furthermore, in the foregoing detailed description, various technical features may be grouped together to streamline the disclosure. This should not be interpreted as intending that an unclaimed disclosed technical feature is essential to any claim. Rather, inventive subject matter may lie in less than all features of a particular disclosed embodiment. Thus, the following claims are hereby incorporated into the detailed description, with each claim standing on its own as a separate embodiment, and it is intended that such embodiments may be combined with each other in various combinations or arrangements. The scope of the invention should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.

The present application provides the following exemplary embodiments or examples, the numbering of which is not to be construed as specifying the level of importance:

embodiment 1 provides a system for conditioning air for an enclosed space. The system may include a plenum having a plenum inlet and a plenum outlet, the plenum configured to direct an air flow path from the plenum inlet to the plenum outlet, and a liquid-to-air membrane energy exchanger (LAMEE) disposed inside the plenum. The LAMEE can include a desiccant flow path separated from an air flow path by a membrane. The LAMEE can be configured to circulate a desiccant through the desiccant flow path and remove water from air in the air flow path. The reduction in energy of the air in the air flow path between the LAMEE inlet and the LAMEE outlet may be approximately equal to the increase in energy of the desiccant in the desiccant flow path between the LAMEE inlet and the LAMEE outlet, and substantially all of the energy removed from the air is transferred to the desiccant. The system may further include a regeneration system fluidly connected to the LAMEE and having a regeneration inlet configured to receive the diluted desiccant stream. The regeneration system may be configured to separate water from the desiccant in the diluted desiccant stream, the regeneration system having a first outlet for discharging the concentrated desiccant stream and a second outlet for discharging a water stream. The system may further comprise one or more cooling components disposed inside the plenum, and at least a portion of the flow of water from the regeneration system may be used by the one or more cooling components as make-up water for operation of the one or more cooling components.

Embodiment 2 provides the system of embodiment 1, optionally configured such that the regeneration system comprises a regeneration unit that thermally separates water and desiccant in the diluted desiccant stream.

Embodiment 3 provides the system of embodiment 2, optionally configured such that the regeneration system comprises a heat exchanger disposed upstream of the regeneration unit and configured to increase the temperature of the diluted desiccant stream before the diluted desiccant stream enters the regeneration unit.

Embodiment 4 provides the system of embodiment 3, optionally configured such that the heat exchanger receives the concentrated desiccant stream from the regeneration unit and transfers heat to the diluted desiccant stream using the concentrated desiccant stream.

Embodiment 5 provides the system of any of embodiments 2-4, optionally configured such that the regeneration system includes a heat source for increasing the temperature of the diluted desiccant stream.

Embodiment 6 provides the system of embodiment 5, optionally configured such that the heat source is the sun.

Embodiment 7 provides the system of embodiment 1, optionally configured such that the regeneration system comprises a regeneration unit that utilizes non-thermal energy to separate water and desiccant in the diluted desiccant stream.

Embodiment 8 provides the system of any of embodiments 1-7, optionally configured such that the concentrated desiccant stream is transported to a desiccant canister configured to receive the concentrated desiccant stream and a diluted desiccant stream exiting the LAMEE.

Embodiment 9 provides the system of embodiment 8, optionally configured such that the output stream from the desiccant canister is at a concentration higher than the concentration of desiccant in the diluted desiccant stream and lower than the concentration of desiccant in the concentrated desiccant stream.

Embodiment 10 provides the system of embodiment 9, optionally configured such that the output stream from the desiccant tank is transported to at least one of the regeneration systems and to the LAMEE for recirculation.

Embodiment 11 provides the system of embodiment 10, optionally further comprising a regulating valve configured to control distribution of the output flow from the desiccant tank to the regeneration system and to the LAMEE.

Embodiment 12 provides the system of embodiment 11, optionally configured such that less than 50 percent by volume of the output stream from the desiccant tank is transported to the regeneration system.

Embodiment 13 provides the system of embodiment 11, optionally configured such that less than 25 percent by volume of the output stream from the desiccant tank is transported to the regeneration system.

Embodiment 14 provides the system of any of embodiments 10-13, optionally configured such that a portion of the output stream from the desiccant tank that is transported to the LAMEE passes through the heat exchanger before being circulated through the LAMEE. The heat exchanger may reduce the temperature of the output stream from the desiccant canister.

Embodiment 15 provides the system of embodiment 8, optionally configured such that a first portion of the diluted desiccant stream exiting the LAMEE is transported to the desiccant canister and a second portion of the diluted desiccant stream exiting the LAMEE is transported to the regeneration system.

Embodiment 16 provides the system of embodiment 15, optionally configured such that the first portion and the second portion are variable during operation of the system.

Embodiment 17 provides the system of any of embodiments 1-16, optionally configured such that the concentration of water in the desiccant at the LAMEE outlet is higher than the concentration of water in the desiccant at the LAMEE inlet.

Embodiment 18 provides the system of any of embodiments 1-17, optionally configured such that the temperature of the desiccant at the LAMEE outlet is higher than the temperature of the desiccant at the LAMEE inlet.

Embodiment 19 provides the system of any of embodiments 1-18, optionally configured such that the LAMEE is a two-fluid LAMEE having a first fluid and a second fluid, and wherein the first fluid is air in the air flow path and the second fluid is desiccant in the desiccant flow path.

Embodiment 20 provides the system of any of embodiments 1-19, optionally configured such that the one or more cooling components comprise an evaporative cooler disposed downstream of the LAMEE.

Embodiment 21 provides the system of any of embodiments 1-20, optionally configured such that an amount of water from the regeneration system is sufficient as make-up water for operation of the evaporative cooler, such that the evaporative cooler operates without an external water supply.

Embodiment 22 provides the system of any of embodiments 20 or 21, optionally configured such that

The LAMEE disposed inside the plenum is a first LAMEE and the evaporative cooler disposed downstream is a second LAMEE.

Embodiment 23 provides the system of embodiment 22, optionally configured such that the second LAMEE adiabatically cools air passing through the process plenum, such that air exiting the second LAMEE is conditioned air for delivery to the enclosed space.

Embodiment 24 provides the system of any of embodiments 1-23, optionally configured such that the one or more cooling components comprise an evaporative cooler configured to cool the desiccant prior to circulating the desiccant through the LAMEE.

Embodiment 25 provides the system of embodiment 24, optionally configured such that the evaporative cooler is external to the plenum.

Embodiment 26 provides the system of any of embodiments 21-25, optionally further comprising a liquid-to-air heat exchanger (LAHX) disposed between the LAMEE and the evaporative cooler, the LAHX configured to pre-cool the air prior to passing the air through the evaporative cooler.

Embodiment 27 provides the system of any of embodiments 1-26, optionally configured such that the plenum is a first plenum configured to receive a flow of purge air, and the system further comprises a second plenum configured to receive a flow of process air from the enclosure.

Embodiment 28 provides the system of embodiment 27, optionally configured such that the one or more cooling components comprise an evaporative cooler disposed in the first plenum downstream of the LAMEE, the evaporative cooler configured to produce water having a reduced temperature. The reduced temperature water may be transported to a LAHX disposed in the second plenum, and the reduced temperature water may be used to cool a process air stream flowing through the LAHX.

Embodiment 29 provides a system for conditioning air for an enclosed space, the system may include a plenum, an outlet configured to direct air thereto from an inlet thereof, a desiccant dryer liquid-to-air membrane energy exchanger (LAMEE) disposed inside the plenum and configured for air passing therethrough, the desiccant dryer LAMEE configured to remove water from the air using desiccant flowing therethrough. The desiccant and air may be separated by a membrane in the LAMEE. The LAMEE can assist in the energy exchange between the air and the desiccant, and the desiccant can collect substantially all of the energy removed from the air. The system may further include an evaporative cooler disposed within the plenum downstream of the desiccant dryer LAMEE and configured for air passing therethrough, the evaporative cooler configured to cool at least one of the air and water circulating through the evaporative cooler. The system may further include a fluid loop coupled to the desiccant dryer LAMEE and the evaporative cooler. The fluid loop may include a regenerator configured to separate water and desiccant in the desiccant stream. The fluid loop may be configured to transport at least a portion of the water removed from the air by the desiccant dryer LAMEE and separated in the regenerator to the evaporative cooler for use as make-up water for operation of the evaporative cooler.

Embodiment 30 provides the system of embodiment 29, optionally configured such that the fluid loop receives an output desiccant stream from a desiccant canister fluidly connected to the outlet of the LAMEE.

Embodiment 31 provides the system of embodiment 30, optionally configured such that the desiccant tank is fluidly connected to an outlet of the regenerator such that the desiccant tank receives the concentrated input desiccant stream discharged from the regenerator and the diluted input desiccant stream exiting the LAMEE.

Embodiment 32 provides the system of embodiment 31, optionally configured such that the fluid loop is a first desiccant loop and the system further comprises a second desiccant loop, the LAMEE being housed within the second desiccant loop. The output desiccant flow from the desiccant canister may be directed to a modulation valve configured to distribute the output desiccant flow to the first desiccant loop and the second desiccant loop.

Embodiment 33 provides the system of embodiment 32, optionally configured such that a greater percentage of the output desiccant stream than the first desiccant loop is directed to the second desiccant loop by weight.

Embodiment 34 provides the system of any of embodiments 29-33, optionally configured such that the regenerator comprises a thermal separation unit.

Embodiment 35 provides the system of embodiment 34, optionally configured such that the regenerator comprises one or more heat sources to increase the temperature of the desiccant stream prior to transferring the desiccant stream into the thermal separation unit.

Embodiment 36 provides the system of embodiment 35, optionally configured such that the one or more heat sources comprises solar energy.

Embodiment 37 provides the system of embodiment 35 or 36, optionally configured such that the one or more heat sources comprises a heat exchanger configured to transfer heat to a desiccant stream using a liquid.

Embodiment 38 provides the system of embodiment 37, optionally configured such that the liquid is a concentrated desiccant stream exiting the regenerator, and the concentrated desiccant stream increases the temperature of the desiccant stream prior to transferring the desiccant stream into the thermal separation unit.

Embodiment 39 provides the system of embodiment 37, optionally configured such that the liquid is a heat transfer fluid configured to transfer heat to the desiccant stream prior to transferring the desiccant stream into the thermal separation unit.

Embodiment 40 provides the system of any of embodiments 29-39, optionally configured such that the fluid loop comprises a concentrated desiccant storage tank configured to receive the concentrated desiccant stream output from the regenerator.

Embodiment 41 provides the system of embodiment 40, optionally configured such that the concentrated desiccant storage tank delivers concentrated desiccant to at least one of the mix tank and the LAMEE.

Embodiment 42 provides the system of embodiment 41, optionally configured such that the concentrated desiccant is intermittently delivered as needed to increase the concentration of the desiccant in the input stream to the LAMEE.

Embodiment 43 provides the system of any of embodiments 29-42, optionally configured such that the fluid loop comprises a distilled water storage tank configured to receive the distilled water output stream from the regenerator and store distilled water for transfer to the evaporative cooler as needed for makeup water.

Embodiment 44 provides the system of any of embodiments 29-43, optionally configured such that an increase in energy of the desiccant between the LAMEE inlet and the LAMEE outlet results in a higher temperature of the desiccant at the outlet of the LAMEE than at the inlet of the LAMEE.

Embodiment 45 provides the system of any of embodiments 29-44, optionally configured such that the desiccant dryer LAMEE is a first LAMEE and the evaporative cooler is a second LAMEE.

Embodiment 46 provides a method for conditioning air for an enclosed space, and the method may include directing air through a process plenum having a plenum inlet and a plenum outlet, directing air through a liquid-to-air energy exchanger (LAMEE) disposed inside the plenum, and directing desiccant through the LAMEE, the desiccant and air separated by a membrane of the LAMEE. The method may further include transferring energy in the LAMEE from the desiccant to the air, the reduction in energy of the air between the LAMEE inlet and the LAMEE outlet being approximately equal to the increase in energy of the desiccant between the LAMEE inlet and the LAMEE outlet. Transferring energy in the LAMEE may include removing water from the air using a desiccant. The first concentration of water in the desiccant at the LAMEE inlet may be lower than the second concentration of water in the desiccant at the LAMEE outlet, and the desiccant at the LAMEE outlet may be a diluted desiccant. The method may further include regenerating a portion of the diluted desiccant in a regenerator to separate water from the desiccant, directing the concentrated desiccant exiting the regenerator to a fluid loop for the desiccant dryer LAMEE, and directing distilled water from the regenerator to one or more evaporative coolers in the conditioning system.

Embodiment 47 provides the method of embodiment 46, optionally configured such that directing the concentrated desiccant exiting the regenerator to a fluid loop for a desiccant dryer LAMEE comprises transporting the concentrated desiccant to a mixing tank that receives diluted desiccant from a LAMEE outlet.

Embodiment 48 provides the method of embodiment 47, optionally further comprising directing a first portion of the diluted desiccant from the LAMEE outlet to the mixing tank and directing a second portion of the diluted desiccant from the LAMEE outlet to the regenerator.

Embodiment 49 provides the method of embodiment 48, optionally configured such that the first portion is larger than the second portion.

Embodiment 50 provides the method of embodiment 48 or 49, optionally further comprising adjusting and varying the first portion and the second portion.

Embodiment 51 provides the method of any of embodiments 47-50, optionally further comprising directing the concentrated desiccant to a concentrated desiccant storage tank prior to transporting the concentrated desiccant to the mixing tank.

Embodiment 52 provides the method of embodiment 47, optionally further comprising mixing the diluted desiccant and the concentrated desiccant in a mixing tank to form a mixed desiccant having a concentration of desiccant that is higher than the concentration of the diluted desiccant and lower than the concentration of the concentrated desiccant.

Embodiment 53 provides the method of embodiment 52, optionally configured such that regenerating a portion of the diluted desiccant comprises transporting a first portion of the mixed desiccant to the LAMEE and a second portion of the mixed desiccant to the regenerator.

Embodiment 54 provides the method of embodiment 53, optionally further comprising adjusting a volume of the second portion of the mixed desiccant transported to the regenerator relative to a volume of the first portion of the mixed desiccant transported to the LAMEE.

Embodiment 55 provides the method of embodiment 54, optionally configured such that adjusting the volume of the second portion of the mixed desiccant transported to the regenerator comprises transporting less than 25 percent by volume of the mixed desiccant exiting the tank to the regenerator.

Embodiment 56 provides the method of any of embodiments 46-55, optionally configured such that the one or more evaporative coolers comprises an evaporative cooler disposed in the plenum downstream of the desiccant dryer LAMEE.

Embodiment 57 provides the method of embodiment 56, optionally configured such that the desiccant dryer LAMEE is a first LAMEE and the downstream evaporative cooler is a second LAMEE.

Embodiment 58 provides the method of embodiment 56 or 57, optionally further comprising using distilled water from the regenerator as make-up water for operation of the evaporative cooler.

Embodiment 59 provides the method of any of embodiments 56-58, optionally configured such that directing air through the process plenum comprises directing scavenging air through the first plenum. The method may further include directing the process air through a second plenum, the process air being from the enclosed space and at an increased temperature, the second plenum configured to cool the process air for delivery back to the enclosed space at a reduced temperature.

Embodiment 60 provides the method of embodiment 59, optionally further comprising passing the reduced temperature water exiting the evaporative cooler to a LAHX disposed in the second plenum to cool the process air directed through the second plenum.

Embodiment 61 provides a system for conditioning air for an enclosed space and the system may include a plurality of conditioning units. Each conditioning unit may include a liquid-to-air film energy exchanger (LAMEE) disposed inside a plenum configured to pass an air stream therethrough and an evaporative cooling component disposed inside the plenum downstream of the LAMEE. The LAMEE can include a desiccant flow path separated from an air flow path by a membrane. The LAMEE can be configured to circulate a desiccant through the desiccant flow path and remove water from the air stream, the concentration of water in the desiccant at the LAMEE outlet being higher than the concentration of water in the desiccant at the LAMEE inlet. The system may further include a regeneration system fluidly connected to the LAMEE outlet of each conditioning unit, the regeneration system having a regeneration inlet configured to receive the diluted desiccant stream, the regeneration system configured to separate water from the desiccant in the diluted desiccant stream, the regeneration system having a first outlet for discharging the concentrated desiccant stream and a second outlet for discharging the distilled water stream. The system may further include a concentrated desiccant storage system configured to receive and store a concentrated desiccant stream from the regenerator system, the concentrated desiccant storage system supplying concentrated desiccant to each conditioning unit as needed for operation of the LAMEE of each conditioning unit. The system may further include a distilled water storage system configured to receive and store the flow of distilled water from the regenerator system, the distilled water storage system supplying water to the evaporative cooling components of each conditioning unit as needed for operation of the evaporative cooling components.

Embodiment 62 provides the system of embodiment 61, optionally configured such that each conditioning unit further comprises a mixing tank configured to receive concentrated desiccant from the concentrated desiccant storage system and diluted desiccant from the LAMEE outlet.

Embodiment 63 provides the system of embodiment 62, optionally configured such that a first portion of the desiccant output flow from the mixing tank of each conditioning unit is transported back to the LAMEE inlet for recirculation and a second portion of the desiccant output flow from the mixing tank of each conditioning unit is transported to the regeneration system.

Embodiment 64 provides the system of embodiment 63, optionally configured such that the volume of the first portion is greater than the volume of the second portion.

Embodiment 65 provides the system of any of embodiments 61-64, optionally configured such that the enclosed space is a data center.

Embodiment 66 provides the system of any of embodiments 61-65, optionally configured such that each conditioning unit receives process air from the enclosed space at an increased temperature and delivers process air at a reduced temperature back to the enclosed space.

Embodiment 67 provides the system of any of embodiments 61-66, optionally further comprising an external source of treated water for delivery to a conditioning unit for standby as needed.

Embodiment 68 provides the system of any of embodiments 61-67, optionally configured such that the LAMEE of each conditioning unit is a first LAMEE and the evaporative cooling component of each conditioning unit is a second LAMEE.

Embodiment 69 provides the system of embodiment 68, optionally configured such that the plenum of each conditioning unit is a first plenum and each conditioning unit further comprises a second plenum configured to pass a process air stream therethrough. The second LAMEE can generate water having a reduced temperature and the water having the reduced temperature can be transported to the second plenum to cool the process air in the process air stream.

Embodiment 70 provides a system or method of any one or any combination of embodiments 1-69, which may optionally be configured such that all of the recited steps or elements are available for use or selected therefrom.

Various aspects of the present disclosure have been described. These and other aspects are within the scope of the following claims.

Claims

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

a plenum having a plenum inlet and a plenum outlet, the plenum configured to direct an airflow path from the plenum inlet to the plenum outlet;

a liquid-to-air membrane energy exchanger (LAMEE) disposed inside the plenum, the LAMEE comprising a desiccant flow path separated from the air flow path by a membrane, the LAMEE configured to circulate desiccant through the desiccant flow path and remove water from air in the air flow path, wherein a reduction in energy of the air in the air flow path between a LAMEE inlet and a LAMEE outlet is about equal to an increase in energy of the desiccant in the desiccant flow path between the LAMEE inlet and the LAMEE outlet, and substantially all of the energy removed from the air is transferred to the desiccant;

a regeneration system fluidly connected to the LAMEE and having a regeneration inlet configured to receive a diluted desiccant stream, the regeneration system configured to separate water from the desiccant in the diluted desiccant stream, the regeneration system having a first outlet for discharging a concentrated desiccant stream and a second outlet for discharging a water stream; and

one or more cooling components disposed inside the plenum, wherein at least a portion of the flow of water from the regeneration system is used by the one or more cooling components as makeup water for operation of the one or more cooling components.

2. The system of claim 1, wherein the regeneration system comprises a regeneration unit that thermally separates the water and the desiccant in the diluted desiccant stream.

3. The system of claim 2, wherein the regeneration system comprises a heat exchanger disposed upstream of the regeneration unit and configured to increase the temperature of the diluted desiccant stream before the diluted desiccant stream enters the regeneration unit.

4. The system of claim 3, wherein the heat exchanger receives the concentrated desiccant stream from the regeneration unit and uses the concentrated desiccant stream to transfer heat to the diluted desiccant stream.

5. The system of claim 2, wherein the regeneration system comprises a heat source for increasing the temperature of the diluted desiccant stream.

6. The system of claim 5, wherein the heat source is the sun.

7. The system of claim 1, wherein the regeneration system comprises a regeneration unit that utilizes non-thermal energy to separate the water and the desiccant in the diluted desiccant stream.

8. The system of claim 1, wherein the concentrated desiccant stream is transported to a desiccant canister configured to receive the concentrated desiccant stream and a diluted desiccant stream exiting the LAMEE.

9. The system of claim 8, wherein the output stream from the desiccant canister is at a concentration higher than the concentration of the desiccant in the diluted desiccant stream and lower than the concentration of the desiccant in the concentrated desiccant stream.

10. The system of claim 9, wherein the output stream from the desiccant tank is transported to at least one of the regeneration systems and to the LAMEE for recirculation.

11. The system of claim 10, further comprising a regulating valve configured to control distribution of the output flow from the desiccant canister to the regeneration system and to the LAMEE.

12. The system of claim 11, wherein less than 50 percent of the output stream from the desiccant canister is transported to the regeneration system on a volume basis.

13. The system of claim 11, wherein less than 25 percent of the output stream from the desiccant canister is transported to the regeneration system on a volume basis.

14. The system of claim 10, wherein a portion of the output stream from the desiccant tank that is transported to the LAMEE passes through a heat exchanger before being circulated through the LAMEE, and wherein the heat exchanger reduces the temperature of the output stream from the desiccant tank.

15. The system of claim 8, wherein a first portion of the diluted desiccant stream exiting the LAMEE is transported to the desiccant canister and a second portion of the diluted desiccant stream exiting the LAMEE is transported to the regeneration system.

16. The system of claim 15, wherein the first portion and the second portion are variable during operation of the system.

17. The system of claim 1, wherein the concentration of water in the desiccant at the LAMEE outlet is higher than the concentration of water in the desiccant at the LAMEE inlet.

18. The system of claim 1, wherein the desiccant at the LAMEE outlet is at a higher temperature than the desiccant at the LAMEE inlet.

19. The system of claim 1, wherein the LAMEE is a two-fluid LAMEE having a first fluid and a second fluid, and wherein the first fluid is the air in the air flow path and the second fluid is the desiccant in the desiccant flow path.

20. The system of claim 1, wherein the one or more cooling components comprise an evaporative cooler disposed downstream of the LAMEE.

21. The system of claim 20, wherein the amount of water from the regeneration system is sufficient as the make-up water for operation of the evaporative cooler such that the evaporative cooler operates without an external water supply.

22. The system of claim 20, wherein the LAMEE disposed inside the plenum is a first LAMEE and the evaporative cooler disposed downstream is a second LAMEE.

23. The system of claim 22, wherein the second LAMEE adiabatically cools the air passing through the process plenum such that the air exiting the second LAMEE is conditioned air for delivery to an enclosed space.

24. The system of claim 20, wherein the one or more cooling components comprise an evaporative cooler configured to cool the desiccant prior to circulating the desiccant through the LAMEE.

25. The system of claim 24, wherein the evaporative cooler is external to the plenum.

26. The system of claim 20, further comprising a liquid-to-air heat exchanger (LAHX) disposed between the LAMEE and the evaporative cooler, the LAHX configured to pre-cool the air prior to passing the air through the evaporative cooler.

27. The system of claim 1, wherein the plenum is a first plenum configured to receive a flow of purge air, and the system further comprises a second plenum configured to receive a flow of process air from the enclosed space.

28. The system of claim 27, wherein the one or more cooling components comprise an evaporative cooler disposed in the first plenum downstream of the LAMEE, the evaporative cooler configured to produce reduced temperature water, and wherein the reduced temperature water is transported to a LAHX disposed in the second plenum and used to cool the process air stream flowing through the LAHX.

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

a plenum configured to direct air from an inlet thereof to an outlet thereof;

a desiccant dryer liquid-to-air membrane energy exchanger (LAMEE) disposed inside the plenum and configured for the air passing therethrough, the desiccant dryer LAMEE configured to remove water from the air using desiccant flowing therethrough, the desiccant and air being separated in the LAMEE by a membrane, wherein the LAMEE facilitates energy exchange between the air and the desiccant, and the desiccant collects substantially all of the energy removed from the air;

an evaporative cooler disposed within the plenum downstream of the desiccant dryer LAMEE and configured for the air passing therethrough, the evaporative cooler configured to cool at least one of the air and water circulating through the evaporative cooler; and

a fluid loop coupled to the desiccant dryer LAMEE and the evaporative cooler, the fluid loop including a regenerator configured to separate water and desiccant in a desiccant stream, wherein the fluid loop is configured to transport at least a portion of the water removed from the air by the desiccant dryer LAMEE and separated in the regenerator to the evaporative cooler for use as make-up water for operation of the evaporative cooler.

30. The system of claim 29, wherein the fluid loop receives an output desiccant stream from a desiccant canister fluidly connected to an outlet of the LAMEE.

31. The system of claim 30, wherein the desiccant tank is fluidly connected to an outlet of the regenerator such that the desiccant tank receives the concentrated input desiccant stream discharged from the regenerator and the diluted input desiccant stream exiting the LAMEE.

32. The system of claim 31, wherein the fluid loop is a first desiccant loop and the system further comprises a second desiccant loop, the LAMEE being housed within the second desiccant loop, and wherein the output desiccant stream from the desiccant canister is directed to a modulating valve configured to distribute the output desiccant stream to the first desiccant loop and the second desiccant loop.

33. The system of claim 32, wherein a greater percentage of the output desiccant stream than the first desiccant loop is directed to the second desiccant loop by weight.

34. The system of claim 29, wherein the regenerator comprises a thermal separation unit.

35. The system of claim 34, wherein the regenerator includes one or more heat sources to increase the temperature of the desiccant stream prior to transferring the desiccant stream into the thermal separation unit.

36. The system of claim 35, wherein the one or more heat sources comprise solar energy.

37. The system of claim 35, wherein the one or more heat sources comprise a heat exchanger configured to transfer heat to the desiccant stream using a liquid.

38. The system of claim 37, wherein the liquid is a concentrated desiccant stream exiting the regenerator, and the concentrated desiccant stream increases a temperature of the desiccant stream prior to transferring the desiccant stream into the thermal separation unit.

39. The system of claim 37, wherein the liquid is a heat transfer fluid configured to transfer heat to the desiccant stream prior to transferring the desiccant stream into the thermal separation unit.

40. The system of claim 29, wherein the fluid loop comprises a concentrated desiccant storage tank configured to receive a concentrated desiccant stream output from the regenerator.

41. The system of claim 40, wherein the concentrated desiccant storage tank delivers concentrated desiccant to at least one of a mix tank and the LAMEE.

42. The system of claim 41, wherein the concentrated desiccant is delivered intermittently as needed to increase the concentration of the desiccant in the input stream to the LAMEE.

43. The system of claim 29, wherein the fluid loop comprises a distilled water storage tank configured to receive a distilled water output stream from the regenerator and store the distilled water for delivery to the evaporative cooler for makeup water as needed.

44. The system of claim 29, wherein the increase in energy of the desiccant between the LAMEE inlet and the LAMEE outlet causes a temperature of the desiccant at the LAMEE outlet to be higher than a temperature of the desiccant at the LAMEE inlet.

45. The system of claim 29, wherein the desiccant dryer LAMEE is a first LAMEE and the evaporative cooler is a second LAMEE.

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

directing air through a process plenum having a plenum inlet and a plenum outlet;

directing the air through a liquid-to-air energy exchanger (LAMEE) disposed inside the plenum;

directing a desiccant through the LAMEE, the desiccant and air separated by a membrane of the LAMEE;

transferring energy in the LAMEE from the desiccant to the air, the reduction in energy of the air between a LAMEE inlet and a LAMEE outlet being about equal to the increase in energy of the desiccant between the LAMEE inlet and the LAMEE outlet, and transferring energy in the LAMEE comprising removing water from the air using the desiccant, the first concentration of water in the desiccant at a LAMEE inlet being lower than the second concentration of water in the desiccant at a LAMEE outlet, the desiccant at the LAMEE outlet being diluted desiccant;

regenerating a portion of the diluted desiccant in a regenerator to separate the water from the desiccant;

directing the concentrated desiccant exiting the regenerator to a fluid loop for the desiccant dryer LAMEE; and

directing distilled water from the regenerator to one or more evaporative coolers in the conditioning system.

47. The method of claim 46, wherein directing the concentrated desiccant exiting the regenerator to a fluid loop for the desiccant dryer LAMEE comprises transporting the concentrated desiccant to a mixing tank that receives the diluted desiccant from the LAMEE outlet.

48. The method of claim 47, further comprising:

directing a first portion of the diluted desiccant from the LAMEE outlet to the mixing tank; and

directing a second portion of the diluted desiccant from the LAMEE outlet to the regenerator.

49. The method of claim 48, wherein the first portion is larger than the second portion.

50. The method of claim 48, further comprising adjusting and varying the first portion and the second portion.

51. The method of claim 47, further comprising:

directing the concentrated desiccant to a concentrated desiccant storage tank prior to transporting the concentrated desiccant to the mixing tank.

52. The method of claim 47, further comprising:

mixing the diluted desiccant and the concentrated desiccant in the mixing tank to form a mixed desiccant having a concentration of desiccant that is higher than the concentration of the diluted desiccant and lower than the concentration of the concentrated desiccant.

53. The method of claim 52, wherein regenerating a portion of the diluted desiccant comprises transporting a first portion of the mixed desiccant to the LAMEE and a second portion of the mixed desiccant to the regenerator.

54. The method of claim 53, further comprising:

adjusting a volume of the second portion of the mixed desiccant transported to the regenerator relative to a volume of the first portion of the mixed desiccant transported to the LAMEE.

55. The method of claim 54, wherein adjusting the volume of the second portion of the mixed desiccant transported to the regenerator comprises transporting less than 25 percent by volume of the mixed desiccant exiting the tank to the regenerator.

56. The method of claim 46, wherein the one or more evaporative coolers comprises an evaporative cooler disposed in the plenum downstream of the desiccant dryer LAMEE.

57. The method of claim 56, wherein the desiccant dryer LAMEE is a first LAMEE and the evaporative cooler downstream is a second LAMEE.

58. The method of claim 56, further comprising:

using the distilled water from the regenerator as make-up water for operation of the evaporative cooler.

59. The method of claim 56, wherein directing air through a process plenum comprises directing scavenge air through a first plenum, and the method further comprises:

directing process air from an enclosure and at an increased temperature through a second plenum configured to cool the process air for delivery back to the enclosure at a reduced temperature.

60. The method of claim 59, further comprising:

passing the reduced temperature water exiting the evaporative cooler to a LAHX disposed in the second plenum to cool the process air directed through the second plenum.

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

a plurality of adjustment units, each adjustment unit comprising:

a liquid-to-air membrane energy exchanger (LAMEE) disposed inside a plenum configured to pass an air stream therethrough, the LAMEE comprising a desiccant flow path separated from the air flow path by a membrane, the LAMEE configured to circulate desiccant through the desiccant flow path and remove water from the air stream, a concentration of water in the desiccant at a LAMEE outlet being higher than a concentration of water in the desiccant at a LAMEE inlet; and

an evaporative cooling component disposed within the plenum downstream of the LAMEE;

a regeneration system fluidly connected to the LAMEE outlet of each conditioning unit, the regeneration system having a regeneration inlet configured to receive a diluted desiccant stream, the regeneration system configured to separate water from the desiccant in the diluted desiccant stream, the regeneration system having a first outlet for discharging a concentrated desiccant stream and a second outlet for discharging a distilled water stream;

a concentrated desiccant storage system configured to receive and store the concentrated desiccant stream from the regenerator system, the concentrated desiccant storage system supplying concentrated desiccant to each conditioning unit as needed for operation of the LAMEE of each conditioning unit; and

a distilled water storage system configured to receive and store the distilled water stream from the regenerator system, the distilled water storage system supplying water to the evaporative cooling components of each conditioning unit as needed for operation of the evaporative cooling components.

62. The system of claim 61, wherein each conditioning unit further comprises a mixing tank configured to receive the concentrated desiccant from the concentrated desiccant storage system and diluted desiccant from the LAMEE outlet.

63. The system of claim 62, wherein a first portion of the desiccant output flow from the mixing tank of each conditioning unit is transported back to the LAMEE inlet for recirculation and a second portion of the desiccant output flow from the mixing tank of each conditioning unit is transported to the regeneration system.

64. The system of claim 63, wherein the volume of the first portion is greater than the volume of the second portion.

65. The system of claim 61, wherein the enclosed space is a data center.

66. The system of claim 61, wherein each conditioning unit receives process air from the enclosed space at an increased temperature and delivers the process air at a reduced temperature back to the enclosed space.

67. The system of claim 61, further comprising an external source of treated water for delivery to the conditioning unit for standby as needed.

68. The system of claim 61, wherein the LAMEE of each conditioning unit is a first LAMEE and the evaporative cooling component of each conditioning unit is a second LAMEE.

69. The system of claim 68, wherein the plenum of each conditioning unit is a first plenum and each conditioning unit further comprises a second plenum configured to pass a process air stream therethrough, and wherein the second LAMEE produces water of reduced temperature and the water of reduced temperature is transported to the second plenum to cool process air in the process air stream.