Abstract:
A split liquid desiccant air conditioning system is disclosed for treating an air stream flowing into a space in a building. The split liquid desiccant air-conditioning system is switchable between operating in a warm weather operation mode and a cold weather operation mode.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority from U.S. Provisional Patent Application No. 61/783,176 filed on Mar. 14, 2013 entitled METHODS AND SYSTEMS FOR MINI-SPLIT LIQUID DESICCANT AIR CONDITIONING, which is hereby incorporated by reference. 
     
    
     BACKGROUND 
       [0002]    The present application relates generally to the use of liquid desiccants to dehumidify and cool, or heat and humidify an air stream entering a space. More specifically, the application relates to the replacement of conventional mini-split air conditioning units with (membrane based) liquid desiccant air conditioning system to accomplish the same heating and cooling capabilities as those conventional mini-split air conditioners. 
         [0003]    Desiccant dehumidification systems—both liquid and solid desiccants—have been used parallel to conventional vapor compression HVAC equipment to help reduce humidity in spaces, particularly in spaces that require large amounts of outdoor air or that have large humidity loads inside the building space itself. (ASHRAE 2012 Handbook of HVAC Systems and Equipment, Chapter 24, p. 24.10). Humid climates, such as for example Miami, Fla. require a lot of energy to properly treat (dehumidify and cool) the fresh air that is required for a space&#39;s occupant comfort. Desiccant dehumidification systems—both solid and liquid—have been used for many years and are generally quite efficient at removing moisture from the air stream. However, liquid desiccant systems generally use concentrated salt solutions such as ionic solutions of LiCl, LiBr or CaCl 2  and water. Such brines are strongly corrosive, even in small quantities, so numerous attempts have been made over the years to prevent desiccant carry-over to the air stream that is to be treated. In recent years efforts have begun to eliminate the risk of desiccant carry-over by employing micro-porous membranes to contain the desiccant. These membrane based liquid desiccant systems have been primarily applied to unitary rooftop units for commercial buildings. However, residential and small commercial buildings often use mini-split air conditioners wherein the condenser is located outside and the evaporator cooling coil is installed in the room or space than needs to be cooled, and unitary rooftop units are not an appropriate choice for servicing those spaces. 
         [0004]    Liquid desiccant systems generally have two separate functions. The conditioning side of the system provides conditioning of air to the required conditions, which are typically set using thermostats or humidistats. The regeneration side of the system provides a reconditioning function of the liquid desiccant so that it can be re-used on the conditioning side. Liquid desiccant is typically pumped between the two sides, and a control system helps to ensure that the liquid desiccant is properly balanced between the two sides as conditions necessitate and that excess heat and moisture are properly dealt with without leading to over-concentrating or under-concentrating the desiccant. 
         [0005]    In many smaller buildings a small evaporator coil is hung high up on a wall or covered by a painting as for example the LG LAN126HNP Art Cool Picture frame. A condenser is installed outside and high pressure refrigerant lines connect the two components. Furthermore a drain line for condensate is installed to remove moisture that is condensed on the evaporator coil to the outside. A liquid desiccant system can significantly reduce electricity consumption and can be easier to install without the need for high pressure refrigerant lines that need to be installed on site. 
         [0006]    Mini-split systems typically take 100% room air through the evaporator coil and fresh air only reaches the room through ventilation and infiltration from other sources. This often can result in high humidity and cool temperatures in the space since the evaporator coil is not very efficient for removing moisture. Rather, the evaporator coil is better suited for sensible cooling. On days where only a small amount of cooling is required the building can reach unacceptable levels of humidity since not enough natural heat is available to balance the large amount of sensible cooling. 
         [0007]    There thus remains a need to provide a retrofitable cooling system for small buildings with high humidity loads, wherein the cooling and dehumidification of indoor air can be accommodated at low capital and energy costs. 
       BRIEF SUMMARY 
       [0008]    Provided herein are methods and systems used for the efficient cooling and dehumidification of an air stream especially in small commercial or residential buildings using a mini-split liquid desiccant air conditioning system. In accordance with one or more embodiments, the liquid desiccant flows down the face of a support plate as a falling film. In accordance with one or more embodiments, the desiccant is contained by a microporous membrane and the air stream is directed in a primarily vertical orientation over the surface of the membrane and whereby both latent and sensible heat are absorbed from the air stream into the liquid desiccant. In accordance with one or more embodiments, the support plate is filled with a heat transfer fluid that ideally is flowing in a direction counter to the air stream. In accordance with one or more embodiments, the system comprises a conditioner that removes latent and sensible heat through the liquid desiccant into the heat transfer fluid and a regenerator that rejects the latent and sensible heat from the heat transfer fluid to the environment. In accordance with one or more embodiments, the heat transfer fluid in the conditioner is cooled by a refrigerant compressor or an external source of cold heat transfer fluid. In accordance with one or more embodiments, the regenerator is heated by a refrigerant compressor or an external source of hot heat transfer fluid. In accordance with one or more embodiments, the refrigerant compressor is reversible to provide heated heat transfer fluid to the conditioner and cold heat transfer fluid to the regenerator and the conditioned air is heat and humidified and the regenerated air is cooled and dehumidified. In accordance with one or more embodiments, the conditioner is mounted against a wall in a space and the regenerator is mounted outside of the building. In accordance with one or more embodiments, the regenerator supplies liquid desiccant to the conditioner through a heat exchanger. In one or more embodiments, the heat exchanger comprises two desiccant lines that are bonded together to provide a thermal contact. In one or more embodiments, the conditioner receives 100% room air. In one or more embodiments, the regenerator receives 100% outside air. In one or more embodiments, the conditioner and evaporator are mounted behind a flat screen TV or flat screen monitor or some similar device. 
         [0009]    In accordance with one or more embodiments a liquid desiccant membrane system employs an indirect evaporator to generate a cold heat transfer fluid wherein the cold heat transfer fluid is used to cool a liquid desiccant conditioner. Furthermore in one or more embodiments, the indirect evaporator receives a portion of the air stream that was earlier treated by the conditioner. In accordance with one or more embodiments, the air stream between the conditioner and indirect evaporator is adjustable through some convenient means, e.g., through a set of adjustable louvers or through a fan with adjustable fan speed. In one or more embodiments, the water supplied to the indirect evaporator is potable water. In one or more embodiments, the water is seawater. In one or more embodiments, the water is waste water. In one or more embodiments, the indirect evaporator uses a membrane to prevent carry-over of non-desirable elements from the seawater or waste water. In one or more embodiments, the water in the indirect evaporator is not cycled back to the top of the indirect evaporator such as would happen in a cooling tower, but between 20% and 80% of the water is evaporated and the remainder is discarded. In one or more embodiments, the indirect evaporator is mounted directly behind or directly next to the conditioner. In one or more embodiments, the conditioner and evaporator are mounted behind a flat screen TV or flat screen monitor or some similar device. In one or more embodiments, the exhaust air from the indirect evaporator is exhausted out of the building space. In one or more embodiments, the liquid desiccant is pumped to a regenerator mounted outside the space through a heat exchanger. In one or more embodiments, the heat exchanger comprises two lines that are thermally bonded together to provide a heat exchange function. In one or more embodiments, the regenerator receives heat from a heat source. In one or more embodiments, the heat source is a solar heat source. In one or more embodiments, the heat source is a gas-fired water heater. In one or more embodiments, the heat source is a steam pipe. In one or more embodiments, the heat source is waste heat from an industrial process or some other convenient heat source. In one or more embodiments, the heat source can be switched to provide heat to the conditioner for winter heating operation. In one or more embodiments, the heat source also provides heat to the indirect evaporator. In one or more embodiments, the indirect evaporator can be directed to provide humid warm air to the space rather than exhausting the air to the outside. 
         [0010]    In accordance with one or more embodiments, the indirect evaporator is used to provide heated, humidified air to a supply air stream to a space while a conditioner is simultaneously used to provide heated, humidified air to the same space. This allows the system to provide heated, humidified air to a space in winter conditions. The conditioner is heated and is desorbing water vapor from a desiccant and the indirect evaporator can be heated as well and is desorbing water vapor from liquid water. In combination the indirect evaporator and conditioner provide heated humidified air to the building space for winter heating conditions. 
         [0011]    In no way is the description of the applications intended to limit the disclosure to these applications. Many construction variations can be envisioned to combine the various elements mentioned above each with its own advantages and disadvantages. The present disclosure in no way is limited to a particular set or combination of such elements. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0012]      FIG. 1  illustrates an exemplary 3-way liquid desiccant air conditioning system using a chiller or external heating or cooling sources. 
           [0013]      FIG. 2  shows an exemplary flexibly configurable membrane module that incorporates 3-way liquid desiccant plates. 
           [0014]      FIG. 3  illustrates an exemplary single membrane plate in the liquid desiccant membrane module of  FIG. 2 . 
           [0015]      FIG. 4  shows a schematic of a conventional mini-split air conditioning system. 
           [0016]      FIG. 5A  shows a schematic of an exemplary chiller assisted mini-split liquid desiccant air conditioning system in a summer cooling mode in accordance with one or more embodiments. 
           [0017]      FIG. 5B  shows a schematic of an exemplary chiller assisted mini-split liquid desiccant air conditioning system in a winter heating mode in accordance with one or more embodiments. 
           [0018]      FIG. 6  shows an alternate embodiment of a mini-split liquid desiccant air conditioning system using an indirect evaporative cooler and an external heat source in accordance with one or more embodiments. 
           [0019]      FIG. 7  shows the liquid desiccant mini-split system of  FIG. 6  configured for operation in a winter heating mode in accordance with one or more embodiments. 
           [0020]      FIG. 8  is a perspective view of an exemplary liquid desiccant mini-split system similar to  FIG. 5A . 
           [0021]      FIG. 9A  illustrates a cut-away rear-view of the system of  FIG. 8 . 
           [0022]      FIG. 9B  illustrates a cut-away front-view of the system of  FIG. 8 . 
           [0023]      FIG. 10  shows a three dimensional view of a liquid desiccant mini-split system of  FIG. 6  in accordance with one or more embodiments. 
           [0024]      FIG. 11  shows a cut-away view of the system of  FIG. 10  in accordance with one or more embodiments. 
           [0025]      FIG. 12  illustrates an exemplary liquid desiccant supply and return structure comprising two bonded plastic tubes creating a heat exchange effect in accordance with one or more embodiments. 
       
    
    
     DETAILED DESCRIPTION 
       [0026]      FIG. 1  depicts a new type of liquid desiccant system as described in more detail in U.S. Patent Application Publication No. US 20120125020, which is incorporated by reference herein. A conditioner  101  comprises a set of plate structures that are internally hollow. A cold heat transfer fluid is generated in cold source  107  and entered into the plates. Liquid desiccant solution at  114  is brought onto the outer surface of the plates and runs down the outer surface of each of the plates. The liquid desiccant runs behind a thin membrane that is located between the air flow and the surface of the plates. Outside air  103  is now blown through the set of wavy plates. The liquid desiccant on the surface of the plates attracts the water vapor in the air flow and the cooling water inside the plates helps to inhibit the air temperature from rising. The treated air  104  is put into a building space. 
         [0027]    The liquid desiccant is collected at the bottom of the wavy plates at  111  and is transported through a heat exchanger  113  to the top of the regenerator  102  to point  115  where the liquid desiccant is distributed across the wavy plates of the regenerator. Return air or optionally outside air  105  is blown across the regenerator plate and water vapor is transported from the liquid desiccant into the leaving air stream  106 . An optional heat source  108  provides the driving force for the regeneration. The hot transfer fluid  110  from the heat source can be put inside the wavy plates of the regenerator similar to the cold heat transfer fluid on the conditioner. Again, the liquid desiccant is collected at the bottom of the wavy plates  102  without the need for either a collection pan or bath so that also on the regenerator the air flow can be horizontal or vertical. An optional heat pump  116  can be used to provide cooling and heating of the liquid desiccant. It is also possible to connect a heat pump between the cold source  107  and the hot source  108 , which is thus pumping heat from the cooling fluids rather than the desiccant. 
         [0028]      FIG. 2  describes a 3-way heat exchanger as described in further detail in U.S. patent application Ser. No. 13/915,199 filed on Jun. 11, 2013, Ser. No. 13/915,222 filed on Jun. 11, 2013, and Ser. No. 13/915,262 filed on Jun. 11, 2013, which are all incorporated by reference herein. A liquid desiccant enters the structure through ports  304  and is directed behind a series of membranes as described in  FIG. 1 . The liquid desiccant is collected and removed through ports  305 . A cooling or heating fluid is provided through ports  306  and runs counter to the air stream  301  inside the hollow plate structures, again as described in  FIG. 1  and in more detail in  FIG. 3 . The cooling or heating fluids exit through ports  307 . The treated air  302  is directed to a space in a building or is exhausted as the case may be. 
         [0029]      FIG. 3  describes a 3-way heat exchanger as described in more detail in U.S. Provisional Patent Application Ser. No. 61/771,340 filed on Mar. 1, 2013, which is incorporated by reference herein. The air stream  251  flows counter to a cooling fluid stream  254 . Membranes  252  contain a liquid desiccant  253  that is falling along the wall  255  that contain a heat transfer fluid  254 . Water vapor  256  entrained in the air stream is able to transition the membrane  252  and is absorbed into the liquid desiccant  253 . The heat of condensation of water  258  that is released during the absorption is conducted through the wall  255  into the heat transfer fluid  254 . Sensible heat  257  from the air stream is also conducted through the membrane  252 , liquid desiccant  253  and wall  255  into the heat transfer fluid  254 . 
         [0030]      FIG. 4  illustrates a schematic diagram of a conventional mini-split air conditioning system as is frequently installed on buildings. The unit comprises a set of indoor components that generate cool, dehumidified air and a set of outdoor components that release heat to the environment. The indoor components comprise a cooling (evaporator) coil  401  through which a fan  407  blows air  408  from the room. The cooling coil cools the air and condenses water vapor on the coil which is collected in drain pan  418  and ducted to the outside  419 . The resulting cooler, drier air  409  is circulated into the space and provides occupant comfort. The cooling coil  401  receives liquid refrigerant at pressures of typically 50-200 psi through line  412 , which has already been expanded to a low temperature and pressure by expansion valve  406 . The pressure of the refrigerant in line  412  is typically 300-600 psi. The cold liquid refrigerant  410  enters the cooling coil  401  where it picks up heat from the air stream  408 . The heat from the air stream evaporates the liquid refrigerant in the coil and the resulting gas is transported through line  404  to the outdoor components and more specifically to the compressor  402  where it is re-compressed to a high pressure of typically 300-600 psi. In some instances the system can have multiple cooling coils  410 , fans  407  and expansion valves  406 , for example a cooling coil assembly could be located in various rooms that need to be cooled. 
         [0031]    Besides the compressor  402 , the outdoor components comprise a condenser coil  403  and a condenser fan  417 . The fan  417  blows outside air  415  through the condenser coil  403  where it picks up heat from the compressor  402  which is rejected by air stream  416 . The compressor  402  creates hot compressed refrigerant in line  411 . The heat of compression is rejected in the condenser coil  403 . In some instances the system can have multiple compressors or multiple condenser coils and fans. The primary electrical energy consuming components are the compressor through electrical line  413 , the condenser fan electrical motor through supply line  414  and the evaporator fan motor through line  405 . In general the compressor uses close to 80% of the electricity required to operate the system, with the condenser and evaporator fans taking about 10% of the electricity each. 
         [0032]      FIG. 5A  illustrates a schematic representation of a liquid desiccant air conditioner system. A 3-way conditioner  503  (which is similar to the conditioner  101  of  FIG. 1 ) receives an air stream  501  from a room (“RA”). Fan  502  moves the air  501  through the conditioner  503  wherein the air is cooled and dehumidified. The resulting cool, dry air  504  (“SA”) is supplied to the room for occupant comfort. The 3-way conditioner  503  receives a concentrated desiccant  527  in the manner explained under  FIGS. 1-3 . It is preferable to use a membrane on the 3-way conditioner  503  to ensure that the desiccant is generally fully contained and is unable to get distributed into the air stream  504 . The diluted desiccant  528 , which contains the captured water vapor is transported to the outside regenerator  522 . Furthermore the chilled water  509  is provided by pump  508 , enters the conditioner module  503  where it picks up heat from the air as well as latent heat released by the capture of water vapor in the desiccant  527 . The warmer water  506  is also brought outside to the heat exchanger  507  on the chiller system  530 . It is worth noting that unlike the mini-split system of  FIG. 4 , which has high pressure between 50 and 600 psi, the lines between the indoor and outdoor system of  FIG. 5A  are all low pressure water and liquid desiccant lines. This allows the lines to be inexpensive plastics rather than refrigerant lines in  FIG. 4 , which are typically copper and need to be braised in order to withstand the high refrigerant pressures. It is also worth noting that the system of  FIG. 5A  does not require a condensate drain line like line  419  in  FIG. 4 . Rather, any moisture that is condensed into the desiccant is removed as part of the desiccant itself. This also eliminates problems with mold growth in standing water that can occur in the conventional mini-split systems of  FIG. 4 . 
         [0033]    The liquid desiccant  528  leaves the conditioner  503  and is moved through the optional heat exchanger  526  to the regenerator  522  by pump  525 . If the desiccant lines  527  and  528  are relatively long they can be thermally connected to each other, which eliminates the need for heat exchanger  526 . 
         [0034]    The chiller system  530  comprises a water to refrigerant evaporator heat exchanger  507  which cools the circulating cooling fluid  506 . The liquid, cold refrigerant  517  evaporates in the heat exchanger  507  thereby absorbing the thermal energy from the cooling fluid  506 . The gaseous refrigerant  510  is now re-compressed by compressor  511 . The compressor  511  ejects hot refrigerant gas  513 , which is liquefied in the condenser heat exchanger  515 . The liquid refrigerant  514  then enters expansion valve  516 , where it rapidly cools and exits at a lower pressure. It is worth noting that the chiller system  530  can be made very compact since the high pressure lines with refrigerant ( 510 ,  513 ,  514  and  517 ) only have to run very short distances. Furthermore, since the entire refrigerant system is located outside of the space that is to be conditioned, it is possible to utilize refrigerants that normally cannot be used in indoor environments such as by way of example, CO 2 , Ammonia and Propane. These refrigerants are sometimes preferable over the commonly used R410A, R407A, R134A or R1234YF refrigerants, but they are undesirable indoor because of flammability or suffocation or inhaling risks. By keeping all of the refrigerants outside, these risks are essentially eliminated. The condenser heat exchanger  515  now releases heat to another cooling fluid loop  519  which brings hot heat transfer fluid  518  to the regenerator  522 . Circulating pump  520  brings the heat transfer fluid back to the condenser  515 . The 3-way regenerator  522  thus receives a dilute liquid desiccant  528  and hot heat transfer fluid  518 . A fan  524  brings outside air  523  (“OA”) through the regenerator  522 . The outside air picks up heat and moisture from the heat transfer fluid  518  and desiccant  528  which results in hot humid exhaust air (“EA”)  521 . 
         [0035]    The compressor  511  receives electrical power  512  and typically accounts for 80% of electrical power consumption of the system. The fan  502  and fan  524  also receive electrical power  505  and  529  respectively and account for most of the remaining power consumption. Pumps  508 ,  520  and  525  have relatively low power consumption. The compressor  511  will operate more efficiently than the compressor  402  in  FIG. 4  for several reasons: the evaporator  507  in  FIG. 5A  will typically operate at higher temperature than the evaporator  401  in  FIG. 4  because the liquid desiccant will condense water at much higher temperature without needing to reach saturation levels in the air stream. Furthermore the condenser  515  in  FIG. 5A  will operate at lower temperatures than the condenser  403  in  FIG. 4  because of the evaporation occurring on the regenerator  522  which effectively keeps the condenser  515  cooler. As a result the system of  FIG. 5A  will use less electricity than the system of  FIG. 4  for similar compressor isoentropic efficiencies. 
         [0036]      FIG. 5B  shows essentially the same system as  FIG. 5A  except that the compressor  511 &#39;s refrigerant direction has been reversed as indicated by the arrows on refrigerant lines  514  and  510 . Reversing the direction of refrigerant flow can be achieved by a 4-way reversing valve (not shown) or other convenient means. It is also possible to instead of reversing the refrigerant flow to direct the hot heat transfer fluid  518  to the conditioner  503  and the cold heat transfer fluid  506  to the regenerator  522 . This will in effect provide heat to the conditioner which will now create hot, humid air  504  for the space for operation in winter mode. In effect the system is now working as a heat pump, pumping heat from the outside air  523  to the space supply air  504 . However unlike the system of  FIG. 4 , which is oftentimes also reversible, there is much less of a risk of the coil freezing because the desiccant  525  usually has much lower crystallization limit than water vapor. In the system of  FIG. 4 , the air stream  523  contains water vapor and if the condenser coil  403  gets too cold, this moisture will condense on the surfaces and create ice formation on those surfaces. The same moisture in the regenerator of  FIG. 5B  will condense in the liquid desiccant which—when managed properly will not crystallize until −60° C. for some desiccants such as LiCl and water. 
         [0037]      FIG. 6  illustrates an alternate embodiment of a mini-split liquid desiccant system. Similar to  FIG. 5A , a 3-way liquid desiccant conditioner  503  receives an air stream  501  (“RA”) moved by fan  502  through the conditioner  503 . However unlike the case of  FIG. 5A , a portion  601  of the supply air stream  504  (“SA”) is directed towards an indirect evaporative cooling module  602  through sets of louvers  610  and  611 . Air stream  601  is usually between 0 and 40% of the flow of air stream  504 . The dry air stream  601  is now directed through the 3-way indirect evaporative cooling module  602  which is constructed similarly to the 3-way conditioner module  503 , except that instead of using a desiccant behind a membrane, the module now has a water film behind such membrane supplied by water source  607 . This water film can be potable water, non-potable water, seawater or waste water or any other convenient water containing substance that is mostly water. The water film evaporates in the dry air stream  601  creating a cooling effect in the heat transfer fluid  604  which is then circulated to the conditioner module as cold heat transfer fluid  605  by pump  603 . The cold water  605  then cools the conditioner module  503 , which in turn creates cooler drier air  504 , which then results in an even stronger cooling effect in the indirect evaporative module  602 . As a result the supply air  504  will ultimately be both dry and cold and is supplied to the space for occupant comfort. Conditioner module  503  also receives a concentrated liquid desiccant  527  that absorbs moisture from the air stream  501 . Dilute liquid desiccant  528  is then returned to the regenerator  522  similar to  FIG. 5A . It is of course possible to locate the indirect evaporative cooler  602  outside of the space rather than inside, but for thermal reasons it is probably better to mount the indirect evaporator  602  in close proximity to the conditioner  503 . The indirect evaporative cooling module  602  does not evaporate all of the water (typically 50 to 80%) and thus a drain  608  is employed. The exhaust air stream  606  (“EA 1 ”) from the module evaporative cooling module  602  is brought to the outside since it is warm and very humid. 
         [0038]    As in  FIG. 5A , the concentrated liquid desiccant  527  and dilute liquid desiccant  528  pass through a heat exchanger  526  by pump  525 . As before one can thermally connect the lines  527  and  528  which eliminates the need for heat exchanger  526 . The 3-way regenerator  522  as before receives an outdoor air stream  523  through fan  524 . And as before a hot heat transfer fluid  518  is applied to the 3-way regenerator module  522  by pump  520 . However unlike the system of  FIG. 5A , there is no heat from a compressor to use in the regenerator  522 , so an external heat source  609  needs to be provided. This heat source can be a gas water heater, a solar module, a solar thermal/PV hybrid module (a PVT module), it can be heat from a steam loop or other convenient source of heat or hot water. In order to prevent over-concentration of the desiccant  528 , a supplemental heat dump  614  can be employed which can temporarily absorb heat from the heat source  609 . An additional fan  613  and air stream  612  are then necessary as well. Of course other forms of heat dumps can be devised and may not always be required. The heat source  609  ensures that the excess water is evaporated from the desiccant  528  so that it can be re-used on the conditioner  503 . As a result the exhaust stream  521  (“EA 2 ”) comprises hot, humid air. It is worth noting that again no high pressure lines are needed between the indoor and outside components of the system. A single water line for water supply is needed and a drain line for the removal of excess water. However a compressor and heat exchanger are no longer required in this embodiment. As a result this system will use significantly less electricity than the system of  FIG. 4  and the system of  FIG. 5A . The major consumption of electricity are now the fans  502  and  524  through electrical supply lines  505  and  529  respectively and the liquid pumps  603 ,  520  and  525 . However these devices consume considerably less power than the compressor  402  in  FIG. 4 . 
         [0039]      FIG. 7  illustrates the system of  FIG. 6  reconfigured slightly to allow for operation in winter heating mode. The heat source  609  now provides hot heat transfer fluid to the conditioner module  503  through lines  701 . As a result the supply air to the space  504  will be warm and humid. It is also possible to provide hot heat transfer fluid  703  to the indirect evaporative cooler  602  and to direct the hot, humid exhaust air  702  to the space rather than to the outside. This increases the available heating and humidification capacity of the system since both the conditioner  503  and the indirect evaporative “cooler”  602  (or “heater” may be a better moniker) are operating to provide the same hot humid air and this can be handy since heating capacity in winter typically needs to be larger than cooling capacity in summer. 
         [0040]      FIG. 8  shows an embodiment of the system of  FIG. 5A . The air intake  801  allows for air from space  805  to enter the conditioner unit  503  (not shown). The air supply exits from roster  803  into the space. A flat screen television  802  or painting, or monitor or any other suitable device can be used to visually hide the conditioner  503 . An external wall  804  would be a logical place to mount the conditioner system. A regenerator and chiller system  807  can be mounted in a convenient outside location  806 . Desiccant supply and return lines  809  and cold heat transfer fluid supply and return lines  808  connect the two sides of the system. 
         [0041]      FIG. 9A  shows a cut-away view of the rear side of the system in  FIG. 8 . The regenerator module  522  receives liquid desiccant from lines  809 . A compressor  511  an expansion valve  516  and two refrigerant to liquid heat exchangers  507  and  515  are also shown. Other components have not been shown for convenience. 
         [0042]      FIG. 9B  shows a cut-away view of the front side of the system in  FIG. 8 . The flat screen TV  802  has been omitted to allow a view of the conditioner module  503 . 
         [0043]      FIG. 10  shows an aspect of an embodiment of the system of  FIG. 6 . The system has an air intake  801  and a supply roster  803  similar to the system of  FIG. 8 . As in  FIG. 8 , a TV  802  or something similar can be used to cover the conditioner module  503 . The unit can be mounted to wall  804  and provide conditioning of the space  805 . The system also has an exhaust  606  that penetrates the wall  804 . On the outside  806 , the regenerator module  902  provides concentrated liquid desiccant to the conditioner section (not shown) through desiccant supply and return lines  809 . A water supply line  901  is also shown. A source of hot heat transfer fluid can be the solar PVT module  903  which provides hot water through line  905  which after being cooled through the regenerator returns heat transfer fluid to the PVT module  903  through line  904 . An integrated hot water storage tank  906  can provide both a hot water buffer as well as a ballast for the PVT module  903 . 
         [0044]      FIG. 11  shows a cut-away view of the system of  FIG. 10 . The conditioner module  503  can be clearly seen as can the indirect evaporator module  602 . Inside the regenerator module  902  one can see the regenerator module  522  as well as the optional heat dump  614  and fan  612 . 
         [0045]      FIG. 12  illustrates a structure  809  for the supply and return of the liquid desiccant to the indoor conditioning unit. The structure comprises a polymer material such as for example an extruded High Density Polypropylene or High Density Polyethylene material the comprises two passages  1201  and  1202  for the supply and return of desiccant respectively. The wall  1203  between the two passages could be manufactured from a thermally conductive polymer, but in many cases that may not be necessary because the length of the structure  809  is by itself sufficient to provide adequate heat exchange capacity between the supply and return liquids. 
         [0046]    Having thus described several illustrative embodiments, it is to be appreciated that various alterations, modifications, and improvements will readily occur to those skilled in the art. Such alterations, modifications, and improvements are intended to form a part of this disclosure, and are intended to be within the spirit and scope of this disclosure. While some examples presented herein involve specific combinations of functions or structural elements, it should be understood that those functions and elements may be combined in other ways according to the present disclosure to accomplish the same or different objectives. In particular, acts, elements, and features discussed in connection with one embodiment are not intended to be excluded from similar or other roles in other embodiments. Additionally, elements and components described herein may be further divided into additional components or joined together to form fewer components for performing the same functions. Accordingly, the foregoing description and attached drawings are by way of example only, and are not intended to be limiting.