Patent Publication Number: US-9845980-B2

Title: Air conditioning system with evaporative cooling system

Description:
BACKGROUND OF THE PRESENT INVENTION 
     Field of Invention 
     The present invention relates to an air conditioning system, and more particularly to an air conditioning system comprising a multiple-effect evaporative condenser which has a substantially improved energy efficiency and water consumption requirement as compared to conventional cooling techniques for an air conditioning system. 
     Description of Related Arts 
     Referring to  FIG. 1  of the drawings, a conventional air conditioning system utilizing a cooling tower is illustrated. In a conventional air conditioning system, cooling water is pumped to flow between a condenser  1 P and a cooling tower  2 P through two water pipes  3 P. The circulation cycles of the cooling water starts at the condenser  1 P. The cooling water enters the condenser  1 P through a water inlet  11 P and absorbs heat from the refrigerant and is pumped out of the condenser  1 P through a water outlet  12 P. The water pipe  3 P extends from the condenser  1 P to the cooling tower  2 P which is typically placed at a distance from the condenser  1 P. For example, the cooling tower  2 P may be placed on the roof of a building. The temperature of the cooling water entering the cooling tower  2 P is arranged to be lowered in the cooling tower  2 P. The difference in temperature between incoming cooling water and outgoing cooling water in the cooling tower  2 P is typically in the range of 5° C. 
     A major disadvantage of this type of conventional air conditioning system is that the distance between the cooling tower  2 P and the condenser  1 P is typically very long. The condenser  1 P is usually placed in the building while the water pipes  3 P connecting the cooling tower  2 P and the condenser  1 P must extend through building structures. This leads to very high manufacturing and maintenance cost of the air conditioning system. Moreover, conventional cooling tower  2 P requires high water circulation rate (approximately 0.73 m 3 /RT·hr), and this results in high power consumption by the relevant water pump  4 P. 
     SUMMARY OF THE PRESENT INVENTION 
     An objective of the present invention is to provide an air conditioning system comprising a multiple-effect evaporative condenser which is capable of effectively and efficiently rejecting heat from the air conditioning system. 
     An objective of the present invention is to provide an air conditioning system with a multiple-effect evaporative condenser which is small in size, light in weight, and can be conveniently and easily installed as compared with conventional central air conditioning system. 
     Another objective of the present invention is to provide a multiple-effect evaporative condenser for an air conditioning system which eliminates the need to have any cooling tower such as that for a typical air conditioning system. In other words, the overall manufacturing and maintenance cost of the air conditioning system can be substantially reduced. 
     Another objective of the present invention is to provide an air conditioning system comprising a multiple-effect evaporative condenser which utilizes a plurality of highly efficient heat exchanging pipes for providing a relatively large area of heat exchanging surfaces. 
     Another objective of the present invention is to provide an air conditioning system which does not require installation of any air conditioning components (such as air conditioning main unit, compressors etc.) in a building so as to allow the building to be fully utilized for its intended purpose without needing to designate predetermined space for accommodating air conditioning components or machines. 
     Another objective of the present invention is to provide an air conditioning system comprising a multiple-effect evaporative condenser which substantially lowers the circulating volume and the rate of cooling water, and the required power for water pumps. Thus, the present invention saves a substantial amount of energy as compared to conventional air conditioning system utilizing water towers. 
     Another objective of the present invention is to provide a multiple-effect evaporative condenser comprising highly efficient heat exchanging pipes each of which comprises a plurality of inner heat exchanging fins for providing relatively large contact surface area. More specifically, the highly efficient heat exchanging pipe is capable of achieving critical heat flux density for a given material of the highly efficient heat exchanging pipe. 
     In one aspect of the present invention, it provides an air conditioning system using a predetermined amount of refrigerant, comprising: 
     an evaporator unit; 
     a compressor unit connected to the evaporator; 
     an evaporative cooling system which comprises at least one multiple-effect evaporative condenser connected to the compressor for effectively cooling the refrigerant, the multiple-effect evaporative condenser comprising: 
     an air inlet side and an air outlet side which is opposite to the air inlet side; 
     a pumping device adapted for pumping a predetermined amount of cooling water at a predetermined flow rate; 
     a first cooling unit, comprising: 
     a first water collection basin for collecting the pumping deviceed from the pumping device; 
     a plurality of first heat exchanging pipes connected to the condenser and immersed in the first water collection basin; and 
     a first fill material unit provided underneath the first heat exchanging pipes, wherein the cooling water collected in the first water collection basin is arranged to sequentially flow through exterior surfaces of the first heat exchanging pipes and the first fill material unit; 
     a second cooling unit, comprising: 
     a second water collection basin positioned underneath the first cooling unit for collecting the cooling water flowing from the first cooling unit; 
     a plurality of second heat exchanging pipes immersed in the second water collection basin; and 
     a second fill material unit provided underneath the second heat exchanging pipes, wherein the cooling water collected in the second water collection basin is arranged to sequentially flow through exterior surfaces of the second heat exchanging pipes and the second fill material unit; and 
     a bottom water collecting basin positioned underneath the second cooling unit for collecting the cooling water flowing from the second cooling unit, 
     the cooling water collected in the bottom water collection tank being arranged to be guided to flow back into the first water collection basin of the first cooling unit, the refrigerant from the evaporator being arranged to flow through the first heat exchanging pipes of the first cooling unit and the second heat exchanging pipes of the second cooling unit in such a manner that the refrigerant is arranged to perform highly efficient heat exchanging process with the cooling water for lowering a temperature of the refrigerant, a predetermined amount of air being drawn from the air inlet side for performing heat exchange with the cooling water flowing through the first fill material unit and the second fill material unit for lowering a temperature of the cooling water, the air having absorbed the heat from the cooling water being discharged out of the first fill material unit and the second fill material unit through the air outlet side. 
     In another aspect of the present invention, it provides an evaporative cooling system comprising at least one multiple-effect evaporative condenser, which comprises: 
     an air inlet side and an air outlet side which is opposite to the air inlet side; 
     a pumping device adapted for pumping a predetermined amount of cooling water at a predetermined flow rate; 
     a first cooling unit, comprising: 
     a first water collection basin for collecting the cooling water from the pumping device; 
     a plurality of first heat exchanging pipes connected to the condenser and immersed in the first water collection basin; and 
     a first fill material unit provided underneath the first heat exchanging pipes, wherein the cooling water collected in the first water collection basin is arranged to sequentially flow through exterior surfaces of the first heat exchanging pipes and the first fill material unit; 
     a second cooling unit, comprising: 
     a second water collection basin positioned underneath the first cooling unit for collecting the cooling water flowing from the first cooling unit; 
     a plurality of second heat exchanging pipes immersed in the second water collection basin; and 
     a second fill material unit provided underneath the second heat exchanging pipes, wherein the cooling water collected in the second water collection basin is arranged to sequentially flow through exterior surfaces of the second heat exchanging pipes and the second fill material unit; and 
     a bottom water collecting basin positioned underneath the second cooling unit for collecting the cooling water flowing from the second cooling unit, 
     the cooling water collected in the bottom water collection tank being arranged to be guided to flow back into the first water collection basin of the first cooling unit, a predetermined amount of working fluid being arranged to flow through the first heat exchanging pipes of the first cooling unit and the second heat exchanging pipes of the second cooling unit in such a manner that the working fluid is arranged to perform highly efficient heat exchanging process with the cooling water for lowering a temperature of the working fluid, a predetermined amount of air being drawn from the air inlet side for performing heat exchange with the cooling water flowing through the first fill material unit and the second fill material unit for lowering a temperature of the cooling water, the air having absorbed the heat from the cooling water being discharged out of the first fill material unit and the second fill material unit through the air outlet side. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a conventional central air conditioning system utilizing a cooling tower. 
         FIG. 2  is a perspective view of an air conditioning system according to a preferred embodiment of the present invention. 
         FIG. 3  is a plan view of the air conditioning system according to the preferred embodiment of the present invention. 
         FIG. 4  is a schematic diagram of the air conditioning system according to the first preferred embodiment of the present invention. 
         FIG. 5  is a sectional view of the air conditioning system along plane B-B of  FIG. 4 , illustrating that the multiple-effect evaporative condenser has five cooling units. 
         FIG. 6  is a sectional view of the air conditioning system alone plane A-A of  FIG. 4 , illustrating that the multiple-effect evaporative condenser has five cooling units. 
         FIG. 7  is a schematic diagram of a multiple-effect evaporative condenser according to the preferred embodiment of the present invention, illustrating that the multiple-effect evaporative condenser has three cooling units. 
         FIG. 8  is another schematic diagram of a multiple-effect evaporative condenser according to the preferred embodiment of the present invention, illustrating that the multiple-effect evaporative condenser has three cooling units. 
         FIG. 9  is a schematic diagram of first cooling unit of the multiple-effect evaporative condenser according to the preferred embodiment of the present invention. 
         FIG. 10  is a schematic diagram of second cooling unit of the multiple-effect evaporative condenser according to the preferred embodiment of the present invention. 
         FIG. 11  is a schematic diagram of bottom cooling unit of the multiple-effect evaporative condenser according to the preferred embodiment of the present invention. 
         FIG. 12  is a plan view of a first passage plate of the first cooling unit according to the preferred embodiment of the present invention. 
         FIG. 13  is a sectional side view of a flow control mechanism of the multiple-effective evaporative condenser along plane C-C of  FIG. 12 , illustrating that first passage holes and first control holes are substantially aligned and overlapped respectively. 
         FIG. 14  is another schematic diagram of the flow control mechanism of the multiple-effective evaporative condenser according to the preferred embodiment of the present invention, illustrating that the first passage holes and the first control holes start to offset. 
         FIG. 15  is a sectional side view of a flow control mechanism of the multiple-effective evaporative condenser along plane D-D of  FIG. 12 . 
         FIG. 16  is a schematic diagram of an automated control system of the flow control mechanism according to the preferred embodiment of the present invention. 
         FIG. 17  is another schematic diagram of the automated control system of the flow control mechanism according to the preferred embodiment of the present invention. 
         FIG. 18  is a sectional side view of a heat exchanging pipe of the multiple-effective evaporative condenser according to a preferred embodiment of the present invention. 
         FIG. 19  is a schematic diagram of a flowing route of the refrigerant flowing through a multiple-effective evaporative condenser according to a preferred embodiment of the present invention. 
         FIG. 20  is another schematic diagram of a flowing route of the refrigerant flowing through a multiple-effective evaporative condenser according to a preferred embodiment of the present invention. 
         FIG. 21  is a schematic diagram of the first heat exchanging pips of the first cooling unit according to the preferred embodiment of the present invention. 
         FIG. 22  is a sectional side view along plane E-E of  FIG. 21 . 
         FIG. 23  is a side view of a first alternative mode of the first water collection basin according to the preferred embodiment of the present invention. 
         FIG. 24  is a side view of a first alternative mode of the second water collection basin according to the preferred embodiment of the present invention. 
         FIG. 25  is a schematic diagram of the first heat exchanging pips of the first cooling unit according to the alternative mode of the preferred embodiment of the present invention. 
         FIG. 26  is a sectional side view along plane F-F of  FIG. 25 . 
         FIG. 27  is a schematic diagram of the second heat exchanging pips of the second cooling unit according to the alternative mode of the preferred embodiment of the present invention. 
         FIG. 28  is a sectional side view along plane G-G of  FIG. 27 . 
         FIG. 29  illustrates block diagram of the air conditioning system according to the preferred embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The following detailed description of the preferred embodiment is the preferred mode of carrying out the invention. The description is not to be taken in any limiting sense. It is presented for the purpose of illustrating the general principles of the present invention. 
     Referring to  FIG. 2  to  FIG. 10  and  FIG. 29  of the drawings, an air conditioning system according to a preferred embodiment of the present invention is illustrated. Broadly, the air conditioning system comprises two evaporator units  2 , two compressor units  1 , and an evaporative cooling system  200  comprising two multiple-effect evaporative condensers  5 . The air conditioning system utilizes a predetermined amount of working fluid, such as a predetermined amount of refrigerant, for performing heat exchange in various components of the air conditioning system and with ambient environment. 
     The air conditioning system further comprises an outer housing  30  for accommodating the evaporator units  2 , the two compressor units  1 , and the multiple-effect evaporative condensers  5 , and a plurality of cooling fans  27  provided on top of the outer housing  30 . 
     As shown in  FIG. 4  of the drawings, the outer housing  30  has a compressor compartment  31  for accommodating the compressor units  1 . Preferably, there are two compressor units  1  accommodated in the compressor compartment  31 . However, the number of the compressor units  1  may be varied to suit different circumstances in which the present invention is operated. The outer housing  30  further has an evaporator compartment  32  for accommodating the evaporator units  2 . Preferably, there are two evaporator units  2  accommodated in the evaporator compartment  12 . However, the number of the evaporator units  2  may be varied to suit different circumstances in which the present invention is operated. The compressor compartment  31  and the evaporator compartment  32  may be provided in a side-by-side manner at one transverse side of the outer housing  30  as shown in  FIG. 3  of the drawings. 
     In this preferred embodiment, the evaporative cooling system  200  comprises two multiple-effect evaporative units  5 . However, the number of the multiple-effect evaporator units  5  may also be varied to suit different circumstances in which the present invention is operated. 
     The multiple-effect evaporative condensers  5  are provided at two longitudinal sides of the outer housing  30  respectively and are connected to the compressor units  1  for cooling a predetermined amount of refrigerant circulating through the air conditioning system. The air conditioning system further comprises a water heater  3  positioned in the outer housing  30  between the two multiple-effect evaporator condensers  5 . 
     Each of the multiple-effect evaporative condensers  5  comprises a pumping device  4  positioned in the outer housing  30 , a first cooling unit  6 , a second cooling unit  7 , and a bottom water collection basin  100 . Each of the multiple-effect evaporative condensers  5  also has an air inlet side  51  and an air outlet side  52  which is opposite to the air inlet side  51 . 
     The pumping device  4  is adapted for pumping a predetermined amount of cooling water at a predetermined flow rate. Each of the multiple-effect evaporative condensers  5  may have its own pumping device  4 . Alternatively, several (such as two) multiple-effect evaporative condensers  5  may share one single pumping device  4  for circulating the cooling water in each of the multiple-effect evaporative condensers  5 , as shown in  FIG. 6  of the drawings. 
     As shown in  FIG. 9  of the drawings, the first cooling unit  6  comprises a first water collection basin  61  for collecting the cooling water from the pumping device  4 , a plurality of first heat exchanging pipes  62  connected to the relevant compressor unit  1  and immersed in the first water collection basin  61 , and a first fill material unit  63  provided underneath the first heat exchanging pipes  62 , wherein the cooling water collected in the first water collection basin  61  is arranged to sequentially flow through exterior surfaces of the first heat exchanging pipes  62  and the first fill material unit  63  for forming a thin water film therein. 
     On the other hand, as shown in  FIG. 10  of the drawings, the second cooling unit  7  comprises a second water collection basin  71  positioned underneath the first cooling unit  6  for collecting the cooling water flowing from the first cooling unit  6 , a plurality of second heat exchanging pipes  72  immersed in the second water collection basin  71 , and a second fill material unit  73  provided underneath the second heat exchanging pipes  72 . The cooling water collected in the second water collection basin  71  is arranged to sequentially flow through exterior surfaces of the second heat exchanging pipes  72  and the second fill material unit  73  for forming a thin water film therein. 
     The bottom water collecting basin  300  is positioned underneath the second cooling unit  7  for collecting the cooling water flowing from the second cooling unit  7 . The cooling water collected in the bottom water collection basin  100  is arranged to be guided to flow back into the first water collection basin  61  of the first cooling unit  6 . On the other hand, the refrigerant from the evaporator unit  2  is arranged to flow through the first heat exchanging pipes  62  of the first cooling unit  6  and the second heat exchanging pipes  72  of the second cooling unit  7  in such a manner that the refrigerant is arranged to perform highly efficient heat exchanging process with the cooling water for lowering a temperature of the refrigerant. A predetermined amount of air is drawn from the air inlet side  51  for performing heat exchange with the cooling water flowing through the first fill material unit  63  and the second fill material unit  73  for lowering a temperature of the cooling water. The air having absorbed the heat from the cooling water is discharged out of the first fill material unit  63  and the second fill material unit  73  through the air outlet side  52 . 
     According to the preferred embodiment of the present invention, each of the multiple-effect evaporative condensers  5  comprises first through fifth cooling units  6 ,  7 ,  8 ,  9 ,  10 . The number of cooling units utilized depend on the circumstances in which the air conditioning system is operated.  FIG. 5  and  FIG. 6  illustrate a situation where the multiple-effect evaporative condenser  5  comprise five cooling units, namely, the first cooling unit  6 , the second cooling unit  7 , the third cooling unit  8 , the fourth cooling unit  9 , and the fifth cooling unit  10 . 
       FIG. 7  and  FIG. 8  illustrate that each of the multiple-effective evaporative condenser  5  has a total of three cooling units, namely the first cooling unit  6 , the second cooling unit  7 , and the third cooling unit  8 . From the above description, it can be shown that when the cooling water passes through one cooling unit, its temperature is arranged to increase by absorbing heat from the relevant heat exchanging pipes and is to be lowered by a predetermined temperature gradient by extracting heat to the ambient air (referred to as one “temperature cooling effect” on the cooling water), so that if the cooling water passes through five cooling units  6 ,  7 ,  8 ,  9 ,  10 , the multiple-effect evaporative condenser  5  has a total of five temperature effects on the cooling water because the cooling water is heated up by the heat exchanging pipes five times and cooled down by the ambient air in the relevant fill material unit five times. 
     Referring back to  FIG. 5  to  FIG. 6  of the drawings, the third cooling unit  8  comprises a third water collection basin  81 , a plurality of third heat exchanging pipes  82  immersed in the third water collection basin  81 , and a third fill material unit  83  provided under the third water collection basin  81 . Similarly, the fourth cooling unit  9  comprises a fourth water collection basin  91 , a plurality of fourth heat exchanging pipes  92  immersed in the fourth water collection basin  91 , and a fourth fill material unit  93  provided under the fourth water collection basin  91 . The fifth cooling unit  10  comprises a fifth water collection basin  101 , a plurality of fifth heat exchanging pipes  102  immersed in the fifth water collection basin  101 , and a fifth fill material unit  103  provided under the fifth water collection basin  101 . Note that where the multiple-effect evaporative condenser  5  has more than five cooling units, each of the additional cooling units will have the same structure as that of first through fifth cooling units  5 ,  6 ,  7 ,  8 ,  9 ,  10 . For example, a sixth cooling unit may comprise a sixth water collection basin, a plurality of sixth heat exchanging pipes, and a sixth fill material unit, so on and so forth. 
       FIG. 5  and  FIG. 6  illustrate two multiple-effect evaporative condensers  5  which are served by one common pumping device  4 . Thus, the bottom water collection basin  100  of each of the multiple-effect evaporative condensers  5  is connected to the pumping device  4  so that the cooling water collected by the bottom water collection basin  100  is arranged to be pumped to the first cooling unit  6  of the respective multiple-effect evaporative condenser  5 . 
     Each of the multiple-effect evaporative condensers  5  further comprises a pumping pipe assembly  18  connecting the pumping device  4  and the first cooling unit  6 . Specifically, the pumping pipe assembly  18  has one end connected to the pumping device  4  and extends upwardly along the corresponding multiple-effect evaporative condenser  5  for guiding the cooling water to flow into the first water collection basin  61  of the first cooling unit  6 . The pumping pipe assembly  18  has a main piping section  181  comprising a main pipe  1811 , and a plurality of branch piping sections  182  each of which has at least one pumping pipe  1821  extended from the main pipe  1811  or a corresponding pumping pipe  1821  of the lower branch piping section  181 . 
     As illustrated in  FIG. 5  of the drawings, the pumping pipe assembly  18  has one main piping section  181  and a first branch piping section  182  upwardly extended from the main piping section  181 , and a second branch piping section  182  upwardly extended from the first branch piping section  182 . The first branch piping section  182  has two branch pipes  1821  bifurcated from the main pipe  1811 , while the second branch piping section  182  has four branch pipes  1821 , two of which are extended from one of the branch pipes  1821  of the first branch piping section  182 , while the other two branch pipes  1821  are extended from another branch pipe  1821  of the first branch piping section  182 . 
     It is important to note that the number of branch piping sections  182  depend on the height and length of the multiple-effect evaporative condenser  5  and can be varied according to different circumstances. The purpose of the pumping pipe assembly  18  is to control the flow rate of the cooling water and to allow the cooling water to be evenly and controllably distributed along a longitudinal length of the first water collection basin  61 . 
     As one may appreciate, each of the branch pipes  1821  is extended from a corresponding branch pipe  1821  of a lower branch piping section  182  or the main pipe  1811 , so that the flow rate of the cooling water gradually reduces when the cooling water travels up along the pumping pipe assembly  18 . 
     Referring to  FIG. 4  and  FIG. 6  of the drawings, two multiple-effect evaporative condensers  5  are illustrated. For the sake of clarity, the two multiple-effect evaporative condensers  5  are named first multiple-effect evaporative condenser  5  and second multiple-effect evaporative condenser  5  in the following descriptions. The first and the second multiple-effect evaporative condensers  5  are structurally identical and are spacedly accommodated in the outer housing  30  in such a manner that their air outlet sides  52  face each other. 
     The cooling water is pumped by the pumping device  4  to flow into the first water collection basin  61  of the first cooling unit  6  through the pumping pipe assembly  18 . The cooling water is arranged to perform heat exchange with the refrigerant flowing through the first heat exchanging pipes  62  and absorb a certain amount of heat. The cooling water is then allowed to flow into the first fill material unit  63  where it forms thin water film under the influence of gravity. The water film performs heat exchange with the air draft so that heat is extracted from the cooling water to the ambient air. The cooling water is then guided to flow into the second water collection basin  71  of the second cooling unit  7  and performs another cycle of heat exchange with the refrigerant flowing through the second heat exchanging pipes  72  and in the second fill material unit  73 . The cooling water is guided to sequentially flow through first through fifth cooling unit  6 ,  7 ,  8 ,  9 ,  10  to absorb heat from the refrigerant flowing through the various heat exchanging pipes. The absorbed heat is subsequently extracted to ambient air in the various fill material units. 
     As shown in  FIG. 11  of the drawings, each of the multiple-effect evaporative condensers  5  further comprises a bottom cooling unit  300  provided underneath the fifth cooling unit  10  for providing additional cooling of the refrigerant. The bottom cooling unit  300  comprises a guiding member  301 , and a plurality of bottom heat exchanging pipes  302  immersed in the bottom water collection basin  100 . The refrigerant passing through the bottom heat exchanging pipes  302  are arranged to perform heat exchange with the cooling water contained in the bottom water collection basin  100 . 
     The guiding member  301  has a blocking portion  3011 , an inclined guiding portion  3012 , and a horizontal guiding portion  3013  extended between the blocking portion  3011  and the inclined guiding portion  3012 . The blocking portion  3011  is upwardly extended from one end of the horizontal guiding portion  3013 , while the inclined guiding portion  3012  is downwardly extended from another end of the horizontal guiding portion  3013 . The guiding member  301  is positioned underneath the fifth cooling unit  10  and above the bottom water collection basin  100 . Optimally, the horizontal guiding portion  3013  should be positioned above the cooling water level by approximately 3 mm to 6 mm. When cooling water falls from the fifth cooling unit  10  and reaches the horizontal guiding portion  3013 , the cooling water is blocked from falling into the bottom water collection basin  100  from the end where the blocking portion  3011  is positioned because the cooling water is blocked by the blocking portion  3011 . Thus, the cooling water is only allowed to fall into the bottom water collection basin  100  via the inclined guiding portion  3012  which is inclinedly and downwardly extended from another end of the horizontal guiding portion  3013 . 
     In the preferred embodiment, the inclined guiding portion  3012  is provided at the air inlet side  51  of the multiple-effective evaporative condenser  5  while the blocking portion  3011  is provided at the air outlet side  52  thereof. Thus, the cooling water is guided to fall into the bottom water collection basin  100  at an outer side (i.e. the same side as the air inlet side  51 ) thereof. As a result, the temperature of the cooling water contained in the bottom water collection basin  100  is uneven. Since the bottom heat exchanging pipes  302  are immersed in the cooling water which falls into the bottom water collection basin  100  at one side only (i.e. outer side), the relatively cool cooling water (from the fifth cooling unit  10 ) is guided or forced to pass through the bottom heat exchanging pipes  302  and absorb heat from the refrigerant passing therethrough. The temperature of the cooling water increases as it absorbs heat from the refrigerant. From simple physics, one may appreciate that water having a higher temperature tends to move upward in a contained space. Thus, when the cooling water absorbs heat from the bottom heat exchanging pipes  302 , it tends to move upward in the bottom water collection basin  100 . 
     Each of the multiple-effect evaporative condensers  5  further comprises a pumping tank  19  communicated with the bottom water collection basin  100 . The pumping tank  19  is positioned adjacent to an inner side (i.e. the same side as the air outlet side  52  of the multiple-effect evaporative condenser  5 ) of the bottom water collection basin  100  such that the relatively warmer cooling water may flow into the pumping tank  19  which also accommodate the pumping device  4 . As shown in  FIG. 11  of the drawings, the bottom water collection basin  100  and the pumping tank  19  share one common sidewall  191  so that the cooling water contained in the bottom water collection basin  100  is allowed to flow into the pumping tank  19  by flowing over the common sidewall  191 . The cooling water then flows into the pumping tank  19  which pumps the cooling water back to the first cooling unit  6  of the relevant multiple-effect evaporative condenser  5 . 
     It is estimated that the circulation rate of the cooling water in the air conditioning system of the present invention is approximately one-fifth of that of conventional air conditioning system having a cooling tower. 
     As shown in  FIG. 9  of the drawings, the first water collection basin  61  has a first stabilizing compartment  611  connected to the pumping pipe assembly  18 , a first heat exchanging compartment  612  provided adjacent to and communicated with the first stabilizing compartment  611  via a first water channel  613 , wherein the first heat exchanging pipes  62  are immersed in the first heat exchanging compartment  612 . The cooling water pumped by the pumping device  4  is guided to flow into the first stabilizing compartment  611 . When the stabilizing compartment  611  is filled with a predetermined amount of cooling water which reaches the first water channel  613 , the cooling water flows into the heat exchanging compartment  612  through the first water channel  613 . The purpose of the first stabilizing compartment  611  is to provide a buffer zone for controlling the flow rate and pressure of the cooling water. These parameters affect the performance of the heat exchanging process between the cooling water and the first heat exchanging pipes  62 . 
     It is worth mentioning that the first water channel  613  should be elongated in shape and extend along a longitudinal direction of the first water collection basin  61  so as to allow the cooling water to evenly flow into the first heat exchanging compartment  612  along a longitudinal direction of the first heat exchanging pipes  62 . As a result, the cooling water enters the first heat exchanging compartment  612  at an even flow rate along the entire length of the first heat exchanging pipes  62 . This structural arrangement also ensures that the first heat exchanging pipes  62  are immersed in the cooling water in its entirety. 
     The first water collection basin  61  has a first inner sidewall  614 , a first outer sidewall  615 , a first partitioning wall  616 , and a first bottom plate  617 , and a first passage plate  618 . The first partitioning wall  616  is provided between the first inner sidewall  614  and the first outer sidewall  615 , and divides the first water collection basin  61  into the first stabilizing compartment  611  and the first heat exchanging compartment  612 , wherein the first water channel  613  is formed on the first partitioning wall  616  along a longitudinal direction thereof. The first stabilizing compartment  611  is formed between the first inner sidewall  614 , the first partitioning wall  616 , and the first bottom plate  617 . The first heat exchanging compartment  612  is formed by the first partitioning wall  616 , the first outer sidewall  615 , and the first passage plate  618 . 
     The first passage plate  618  has a plurality of first passage holes  6181  for allowing the cooling water contained in the first heat exchanging compartment  612  to fall into the first fill material unit  63 . Referring to  FIG. 12  of the drawings, the first passage holes  6181  are distributed along the first passage plate  618  in a predetermined array, wherein a center of each of the first passage holes  6181  in a particular row is arranged not to align with that of the first passage holes  6181  in the next row. Moreover, each two adjacent first passage holes  6181  of an upper row thereof is arranged to form a triangular distribution with a corresponding first passage hole  6181  of the adjacent row of the first passage holes  6181 , as shown in  FIG. 12  of the drawings. The first passage holes  6181  all have identical shape and size. 
     Referring to  FIG. 9  to  FIG. 17  of the drawings, each of the multiple-effect evaporative condensers  5  comprises a flow control mechanism  17  which comprises at least one control plate  171  movably provided underneath the first passage plate  618  of the first water collection basin  61 , and at least one driving member  172  connected to the first control plate  171  for driving the control plate  171  to move in a horizontal and reciprocal manner. The control plate  171  has a plurality of control holes  1711  spacedly distributed thereon. The number, size, and shape of the control holes  1711  are identical to those of the first passage holes  6181 . Moreover, centers of the first passage holes  6181  are normally aligned with those of the control holes  1711  respectively. The flow control mechanism  17  further comprises a plurality of securing members  173  mounted on the first water collection basin  61  and is arranged to normally exert an upward biasing force toward the control plate  171  so as to maintain a predetermined distance between the control plate  171  and the first passage plate  618 . 
     In this preferred embodiment, the driving member  172  comprises an adjustment screw adjustably connected between the first water collection basin  61  and the control plate  171  for driving the control plate  171  to move in a horizontal and reciprocal manner. 
     As shown in  FIG. 13  of the drawings, when each of the first passage holes  6181  is aligned or substantially overlap with a corresponding control hole  1711 , the cooling water in the first water collection basin  61  may pass through the first passage plate  618  and the control plate  171  at maximum flow rate. However, as shown in  FIG. 13  and  FIG. 14  of the drawings, when the control plate  171  is driven to move horizontally, the control holes  1711  and the first passages holes  6181  no longer align and flow rate of the cooling water passing through the control plate  171  and the first passage plate  618  will decrease. When the control plate  171  is moved such that each of the control holes  1711  blocks the corresponding first passage hole  6181 , the flow rate of the cooling water is at its minimum, which is approximately one-third of the maximum flow rate of the cooling water. 
     The purpose of the flow control mechanism  17  is to control the flow rate of the cooling water flowing from the first cooling unit  6  to the second cooling unit  7 , or from an upper cooling unit to a lower cooling unit. The controlled flow rate ensures that the heat exchanging pipes, such as the second heat exchanging pipes  72 , can be fully immersed in the cooling water so as to perform the heat exchange process in the most effective and efficient manner. 
     Referring to  FIG. 15  of the drawings, the first water collection basin  61  further has a pair of first securing slots  619  formed at lower portions of the first partitioning wall  616  and the first outer sidewall  615  respectively. Each of the first securing slots  619  is elongated along a longitudinal direction of the first water collection basin  61 , wherein the securing members  173  are mounted in the first securing slots  619  respectively. In this preferred embodiment, each of the securing members  173  is a resilient element which normally exerts an upward biasing force against the control plate  171 . 
     It is worth mentioning that the first water collection basin  61  (or other water collection basins used in the present invention) can be manufactured as an integral body for ensuring maximum structural integrity and minimum manufacturing cost. The material used may be plastic material or stainless steel. 
     Referring to  FIG. 16  to  FIG. 17  of the drawings, the flow control mechanism  17  further comprises an automated control system  174  operatively connected to at least one driving member  172 . The automated control system  174  comprises a central control unit  1741 , a connecting member  1742  connected between the central control unit  1741  and the driving member  172 , and a sensor  1743  provided in the first water collection basin  61  and electrically connected to the central control unit  1741 . 
     The sensor  1743  detects the water level in the first water collection basin  61  and sends a signal to the central control unit  1741 , which is pre-programmed to respond to the sensor signal. The central control unit  1741  is then arranged to drive the connecting member  1742  to move horizontally so as to drive the driving member  172  to move in the same direction for controlling the flow rate of the cooling water flowing through the first passage plate  618 . 
     Referring back to  FIG. 9  of the drawings, the first cooling unit  6  further comprises a first water distributing panel  610  having a plurality of distribution openings  6101  mounted between the first water collection basin  61  and the first fill material unit  63  of the first cooling unit  6  for allowing the cooling water flowing from the first water collection basin  61  to be evenly distributed into the first fill material unit  63  along a transverse direction thereof. The purpose of the first water distributing panel  610  is to ensure proper formation of the water film in the first fill material unit  63  and optimal heat exchange performance between the water film and the ambient air. 
     Furthermore, each of the evaporative condensers  5  further comprises at least one filter member  15  supported between the first cooling unit  6  and the second cooling unit  7  for filtering unwanted substances from the cooling water flowing from the first cooling unit  6  to the second cooling unit  7 , as shown in  FIG. 10  of the drawings. 
     As shown in  FIG. 10  of the drawings, the second water collection basin  71  has a second heat exchanging compartment  712 , wherein the second heat exchanging pipes  72  are immersed in the second heat exchanging compartment  712 . The cooling water coming from the first cooling unit  6  is guided to flow into the second heat exchanging compartment  712  via the filter member  15 . 
     The second water collection basin  71  has a second inner sidewall  714 , a second outer sidewall  715 , and a second passage plate  718 . The second heat exchanging compartment  712  is defined within the second inner sidewall  714 , the second outer sidewall  715 , and the second passage plate  718 . The second passage plate  718  has a plurality of second passage holes  7181  for allowing the cooling water contained in the second heat exchanging compartment  712  to fall into the bottom water collection basin  100  or an additional cooling unit, such as the third cooling unit  8 , when the multiple-effective evaporative condenser  5  has more than two cooling units. Referring to  FIG. 12  of the drawings, the second passage holes  7181  are distributed along the second passage plate  718  in a predetermined array, wherein a center of each of the second passage holes  7181  in a particular row is arranged not to align with that of the second passage holes  7181  in the next row. Moreover, each two adjacent second passage holes  7181  of an upper row thereof is arranged to form a triangular distribution with a corresponding second passage hole  7181  of the adjacent row of the second passage holes  7181  as shown in  FIG. 12  of the drawings. The second passage holes  7181  all have identical shape and size. These structures are identical to that of the first passage plate  618 , and the first passage holes  6181 . 
     In this preferred embodiment, the flow control mechanism  17  comprises a plurality of control plates  171  provided underneath the first passage plate  618  and the second passage plate  718 , and a plurality of driving members  172  connected to the control plates  171  respectively for driving the control plates  171  to move in a horizontal and reciprocal manner respectively, as shown in  FIG. 9  and  FIG. 10  of the drawings. Generally speaking, the flow control mechanism  17  comprises the same number of control plates  171  as that of the cooling units  6 ,  7 ,  8 ,  9 ,  10 . In other words, when the multiple-effective evaporative condensers  5  comprises first through fifth cooling units  6 ,  7 ,  8 ,  9 ,  10 , the flow control mechanism will comprise five control plates  171  and five driving members  172 . The structure of each of the control plates  171  and the driving members  172  is identical and has been described above. This structure is illustrated in  FIG. 17  of the drawings. 
     Referring to  FIG. 15  of the drawings, the second water collection basin  71  further has a pair of second securing slots  719  formed at lower portions of the second inner side wall  714  and the second outer sidewall  715  respectively. Each of the second securing slots  719  is elongated along a longitudinal direction of the second water collection basin  71 , wherein the corresponding securing members  173  are mounted in the second securing slots  719  respectively. Again, in this preferred embodiment, each of the securing members  173  is a resilient element which normally exert an upward biasing force against the corresponding control plate  171 . 
     As mentioned above and as shown in  FIG. 16  to  FIG. 17  of the drawings, the flow control mechanism  17  may be operated through the automated control system  174  operatively connected to all the driving members  172  for electrically and automatically controlling the movement of all of the driving members and ultimately the control plates  171 . 
     Referring back to  FIG. 10  of the drawings, the second cooling unit  7  further comprises a second water distributing panel  710  having a plurality of distribution openings  7101  mounted between the second water collection basin  71  and the second fill material unit  73  of the second cooling unit  7  for allowing the cooling water flowing from the second water collection basin  71  to be evenly distributed into the second fill material unit  73  along a transverse direction thereof. The purpose of the second water distributing panel  710  is to ensure proper formation of the water film in the second fill material unit  73  and optimal heat exchange performance between the water film and the ambient air. 
     Furthermore, each of the evaporative condensers  5  further comprises a plurality of filter members  15  supported between each two cooling units for filtering unwanted substances from the cooling water flowing from an upper cooling unit to an immediately lower cooling unit. 
     Referring to  FIG. 18  of the drawings, each of the first heat exchanging pipes  62  comprises a first pipe body  621  and a plurality of first retention members  622  spacedly formed in the first pipe body  621 , and a plurality of first heat exchanging fins  623  extended from an inner surface  6213  of the pipe body  621 . Specifically, the first pipe body  621  has two curved side portions  6211  and a substantially flat mid portion  6212  extending between the two curved side portions to form rectangular cross sectional shape at the mid portion  6212  and two semicircular cross sectional shapes at two curved side portions  621  of the first heat exchanging pipe  62 . 
     Furthermore, the retention members  622  are spacedly distributed in the flat mid portion  6212  along a transverse direction of the corresponding pipe body  621  so as to form a plurality of first pipe cavities  624 . Each of the retention members  622  has a predetermined elasticity for reinforcing the structural integrity of the corresponding first heat exchanging pipe  62 . On the other hand, each of the first heat exchanging fins  623  are extended from an inner surface of the first pipe body  621 . The first heat exchanging fins  623  are spacedly and evenly distributed along the inner surface  6213  of first pipe body  621  for enhancing heat exchange performance between the refrigerant flowing through the corresponding first heat exchanging pipe  62  and the cooling water. 
     When the first heat exchanging pipes  62  operate under vacuum condition, or when the first heat exchanging pipes  62  are subject to higher external pressure (meaning negative pressure inside the pipes  62 ), the first heat exchanging fins  623  may be used to withstand a certain amount of external pressure so as to reinforcing the structural integrity of the first heat exchanging pipes  62 . The length of the first heat exchanging fins  623  depend on the actual circumstances in which the first heat exchanging pipes  62  are used. 
     On the other hand, when the first heat exchanging pipes  62  are subject to positive pressure inside the pipes  62  (such as for a typical air conditioning system), the first retention members  622 , having a predetermined elasticity, will exert a pulling force to the first pipe body  621  and therefore may assist in withstanding such positive pressure developed inside the first pipe body  621 . 
     On the other hand, the second heat exchanging pipes  72  are structurally identical to the first heat exchanging pipes  62 . So, also referring to  FIG. 18  of the drawings, each of the second heat exchanging pipes  72  comprises a second pipe body  721  and a plurality of second retention members  722  spacedly formed in the second pipe body  721 , and a plurality of second heat exchanging fins  723  extended from an inner surface  7213  of the pipe body  721 . Specifically, the second pipe body  721  has two curved side portions  7211  and a substantially flat mid portion  7212  extending between the two curved side portions to form rectangular cross sectional shape at the mid portion  7212  and two semicircular cross sectional shapes at two curved side portions  721  of the second heat exchanging pipe  72 . 
     Furthermore, the retention members  722  are spacedly distributed in the flat mid portion  7212  along a transverse direction of the corresponding pipe body  721  so as to form a plurality of second pipe cavities  724 . Each of the retention members  722  has a predetermined elasticity for reinforcing the structural integrity of the corresponding second heat exchanging pipe  72 . On the other hand, each of the second heat exchanging fins  723  are extended from an inner surface of the second pipe body  721 . The second heat exchanging fins  723  are spacedly and evenly distributed along the inner surface  7213  of second pipe body  721  for enhancing heat exchange performance between the refrigerant flowing through the corresponding second heat exchanging pipe  72  and the cooling water. 
     It is worth mentioning that when the multiple-effect evaporative condenser  5  comprises many cooling units, such as the above-mentioned first through fifth cooling units  6 ,  7 ,  8 ,  9 ,  10 , the third through fifth heat exchanging pipes  82 ,  92 ,  102  are structurally identical to the first heat exchanging pipes  62  and the second heat exchanging pipes  72  described above. 
     According to the preferred embodiment of the present invention, each of the first through fifth heat exchanging pipes  62 ,  72 ,  82 ,  92 ,  102  are configured from aluminum which can be recycled and reused very conveniently and economically. In order to make the heat exchanging pipes to resist corrosion and unwanted oxidation, each of the heat exchanging pipes  62 ,  72 ,  82 ,  92 ,  102  has a thin oxidation layer formed on an exterior surface and an interior surface thereof for preventing further corrosion of the relevant heat exchanging pipe. The formation of this thin oxidation layer can be by anode oxidation method. 
     Moreover, each of the heat exchanging pipes  62 ,  72 ,  82 ,  92 ,  102  may also have a thin layer of polytetrafluoroethylene formed on an exterior surface thereof to prevent unwanted substances from attaching on the exterior surfaces of the heat exchanging pipes  62 ,  72 ,  82 ,  92 ,  102 . 
     The use of aluminum for the heat exchanging pipes  62 ,  72 ,  82 ,  92 ,  102  allows reduction of manufacturing cost by approximately 50% as compared with traditional heat exchanging pipes, which are configured from copper. Possible corrosion problem is effectively resolved by the introduction of the thin oxidation layer on an exterior surface and an interior surface of each of the heat exchanging pipes  62  ( 72 ) ( 82 ) ( 92 ) ( 102 ) and the addition of the thin layer of thin layer of polytetrafluoroethylene on the exterior surfaces of the heat exchanging pipes  62  ( 72 ) ( 82 ) ( 92 ) ( 102 ). 
     It can be appreciated that when the use of the multiple-effect evaporative condensers  5 , the entire air conditioning system will become extremely compact. The outer housing  30  and all other components can be put on top of a building. Unlike traditional air conditioning systems which utilize some sorts of cooling towers, the present invention does not require users to install any other components or designate any areas in the building for accommodating other components. 
     Referring to  FIG. 19  of the drawings, it illustrates that the first heat exchanging pipes  62 , the second heat exchanging pipes  72  and the third heat exchanging pipes  82  are connected in parallel. As a result, the refrigerant enters the relevant multiple-effect evaporative condenser  5  and passes through the first through third heat exchanging pipes  62 ,  72 ,  82  at the same time. After passing through each of the first through third heat exchanging pipes  62 ,  72 ,  82 , the temperature of the refrigerant will be lowered and the refrigerant is arranged to exit the multiple-effect evaporative condenser  5 . 
     Referring to  FIG. 8  and  FIG. 20  of the drawings, two of the multiple-effect evaporative condensers  5  may form an evaporative condenser group for cooling the refrigerant. For example, two multiple-effect evaporative condensers  5  may be placed side-by-side in which the air outlet side  52  of one multiple-effective evaporative condenser  5  faces the air inlet side  51  of another multiple-effect evaporative condenser  5 . Moreover, the refrigerant flowing through the first heat exchanging pipes  62  of one multiple-effect evaporative condenser  5  is arranged to flow into the first heat exchanging pipes  62  of another multiple-effect evaporative condenser  5 . Likewise, the refrigerant flowing through the second heat exchanging pipes  72  of one multiple-effect evaporative condenser  5  is arranged to flow into the second heat exchanging pipes  72  of another multiple-effect evaporative condenser  5 . The refrigerant flowing through the third heat exchanging pipes  82  of one multiple-effect evaporative condenser  5  is arranged to flow into the third heat exchanging pipes  82  of another multiple-effect evaporative condenser  5 . 
     In the arrangement illustrated in  FIG. 20 , ambient air should be drawn in the direction which is opposite to the flow of the refrigerant. For example, if the refrigerant is flowing from the first multiple-effect evaporative condenser  5  to a second multiple-effect evaporative condenser  5 , the ambient air should be drawn from the second multiple-effect evaporative condenser  5  to the first multiple-effect evaporative condenser  5 . 
     Referring to  FIG. 21  to  FIG. 22  of the drawings, the first cooling unit  6  further comprises a first guiding system  64  connected to the first heat exchanging pipes  62  to divide the first heat exchanging pipes  62  into several piping groups so as to guide the refrigerant to flow through the various piping groups in a predetermined order. Specifically, the first guiding system  64  comprises a first inlet collection pipe  641  and a first guiding pipe  642 , wherein each of the first heat exchanging pipes  62  has one end connected to first inlet collection pipe  641 , and another end connected to the first guiding pipe  642 . As shown in  FIG. 21  of the drawings, the first inlet collection pipe  641  has a first fluid inlet  6411 , a first fluid outlet  6412 , and a divider  6413  provided in the first inlet collection pipe  641  to divide the first inlet collection pipe  641  into an inlet portion  6414  and an outlet portion  6415 . The divider  6413  prevents fluid from passing from one side of the divider  6413  to the other side of the divider  6413  (i.e. the fluid is prevented from passing from the first inlet portion  6414  to the first outlet portion  6415 ). The first fluid inlet  6411  is formed on the first inlet portion  6414 , while the first fluid outlet  6412  is formed on the first outlet portion  6415 . 
     According to the preferred embodiment of the present invention, there are altogether four first heat exchanging pipes  62  which are divided into two piping groups. The refrigerant enters the first inlet collection pipe  641  through the first fluid inlet  6411 . The first piping group has two first heat exchanging pipes  62  which are connected to the first inlet portion  6414  while the second piping group has another two of the first heat exchanging pipes  62  which are connected to the first outlet portion  6415 . Thus, the refrigerant entering the first inlet collection pipe  641  is guided to flow through the two heat exchanging pipes  62  of the first piping group. The refrigerant then leaves the two corresponding first heat exchanging pipes  62  and enters the first guiding pipe  642 . The refrigerant flowing in the first guiding pipe  642  is allowed to enter the other two first heat exchanging pipes  62  of the second piping group. The refrigerant is then guided to flow through the two first heat exchanging pipes  62  of the second piping group. The refrigerant then exits the first inlet collection pipe  641  through the first fluid outlet  6412 . The refrigerant flowing through the first heat exchanging pipes  62  are arranged to perform heat exchange with the cooling water passing through the first cooling unit  6 . 
     In addition, the first guiding system  64  further comprises a plurality of first heat exchanging fins  623  extended between each two adjacent first heat exchanging pipes  62  for substantially increasing a surface area of heat exchange between the first heat exchanging pipes  62  and the cooling water, and for reinforcing a structural integrity of the first guiding system  64 . These first heat exchanging fins  623  may be integrally extended from an outer surface of the first heat exchanging pipes  62 , or externally attached or welded on the outer surfaces of the first heat exchanging pipes  62 . 
     The second cooling unit  7  further comprises a second guiding system  74  connected to the second heat exchanging pipes  72  to divide the second heat exchanging pipes  72  into a predetermined number of piping groups, and for guiding the refrigerant to flow through the second heat exchanging pipes  72  in a predetermined order. The structure of the second guiding system  74  is identical to that of the first guiding system  64 . Thus, the second guiding system  74  comprises a second inlet collection pipe  741  and a second guiding pipe  742 , wherein each of the second heat exchanging pipes  72  has one end connected to second inlet collection pipe  741 , and another end connected to the second guiding pipe  742 . As shown in  FIG. 21  of the drawings, the second inlet collection pipe  741  has a second fluid inlet  7411 , a second fluid outlet  7412 , and a second divider  7413  provided in the second inlet collection pipe  741  to divide the second inlet collection pipe  741  into an inlet portion  7414  and an outlet portion  7415 . The second divider  7413  prevents fluid from passing from one side of the second divider  7413  to the other side of the second divider  7413  (i.e. the fluid is prevented from passing from the second inlet portion  7414  to the second outlet portion  7415 ). The second fluid inlet  7411  is formed on the second inlet portion  7414 , while the second fluid outlet  7412  is formed on the second outlet portion  7415 . 
     Again, there are altogether four second heat exchanging pipes  72  which are divided into two piping groups. The refrigerant enters the second inlet collection pipe  741  through the second fluid inlet  7411 . The first piping group has two of the second heat exchanging pipes  72  which are connected to the second inlet portion  7414  while another piping group has the remaining two of the second heat exchanging pipes  72  which are connected to the second outlet portion  7415 . Thus, the refrigerant entering the second inlet collection pipe  741  is guided to flow through the two heat exchanging pipes  72  which are connected to the second inlet portion  7414  (i.e. the first piping group). The refrigerant then leaves the two second heat exchanging pipes  72  and enters the second guiding pipe  742 . The refrigerant flowing in the second guiding pipe  742  is allowed to enter the other two second heat exchanging pipes  72  which are connected to the second outlet portion  7415  (i.e. the second piping group). The refrigerant is then guided to flow through the two second heat exchanging pipes  72  which are connected to the second outlet portion  7415  and enters it. The refrigerant then exits the second inlet collection pipe  741  through the second fluid outlet  7412 . The refrigerant flowing through the second heat exchanging pipes  72  are arranged to perform heat exchange with the cooling water passing through the second cooling unit  7 . 
     In addition, the second guiding system  74  further comprises a plurality of second heat exchanging fins  723  extended between each two adjacent second heat exchanging pipes  72  for substantially increasing a surface area of heat exchange between the second heat exchanging pipes  72  and the cooling water, and for reinforcing a structural integrity of the second guiding system  74 . These second heat exchanging fins  723  may be integrally extended from an outer surface of the second heat exchanging pipes  72 , or externally attached or welded on the outer surfaces of the second heat exchanging pipes  72 . 
     It is important to mention at this stage that the above-mentioned configuration of the first guiding system  64 , the second guiding system  74 , the first heat exchanging pipes  62 , the second heat exchanging pipes  72 , and the number of piping groups are for illustrative purpose only and can actually be varied according to the circumstances in which the present invention is operated. 
     Referring to  FIG. 23  of the drawings, an alternative mode of the air conditioning system according to the preferred embodiment of the present invention is illustrated. The alternative mode is identical to the preferred embodiment as described above except the first water collection basin  61 ′ and the second water collection basin  71 ′. According to the alternative mode, the first water collection basin  61 ′ further comprises a supporting member  614 ′ securely mounted at a lower portion thereof, a plurality of top separating panels  611 ′ spacedly extended from a top ceiling  613 ′ of the first water collection basin  61 ′, and a plurality of bottom separating panels  6150 ′ spacedly and upwardly extended from the supporting member  614 ′ to divide the first heat exchanging compartment  612 ′ into a plurality of heat exchanging chambers  613 ′. 
     As shown in  FIG. 23  of the drawings, the piping groups of the first heat exchanging pipes  62  are received in the heat exchanging chambers  613 ′ respectively. The first (leftmost) heat exchanging chamber  613 ′ is formed between the first partitioning wall  616 ′ and the leftmost top separating panel  611 ′. The second heat exchanging chamber  613 ′ is formed between the leftmost separating panel  611 ′ and the adjacent bottom separating panel  6150 ′ which is extended from the supporting member  614 ′. The next heat exchanging chamber  613 ′ is formed between the bottom separating panel  6150 ′ and the next top separating panel  611 ′. The next heat exchanging chamber  613 ′ is formed between the top separating panel  611 ′ and the next bottom separating panel  6150 ′. The last heat exchanging chamber  613 ′ is formed between the bottom separating panel  6150 ′ and an outer sidewall of the first water collection basin  61 ′. 
     In other words, apart from the two side heat exchanging chambers  613 ′ (i.e. the leftmost heat exchanging chamber  613 ′ and the rightmost heat exchanging chamber  613 ′), each of the remaining heat exchanging chambers  613 ′ is defined by one top separating panel  6150 ′ and an adjacent bottom separating panel  6150 ′, wherein each of the piping groups is received in one of the heat exchanging chambers  613 ′. 
     As a result, the cooling water entering the first heat exchanging compartment  612 ′ via the first water channel  613  is forced or guided to flow through each of the heat exchanging chambers  613 ′ and the corresponding heat exchanging pipes  62  of the corresponding piping group. It is worth mentioning that a length of the supporting member  614 ′ is less than that of the heat exchanging compartment  612 ′ so that the rightmost heat exchanging chamber  613 ′ is formed between the rightmost bottom separating panel  6150 ′ and the first outer sidewall  615 ′. After passing through the last heat exchanging chamber  613 ′, the cooling water is then guided to flow through the first bottom plate  617 ′ and the first water distributing panel  610 ′. The temperature of the cooling water leaving the heat exchanging compartment  612 ′ is increased to a predetermined amount so as to maximize the heat exchanging efficiency between the cooling water and the ambient air in the first fill material unit  63 ′. 
     Note that a space between each two top separating panels  611 ′ and each two bottom separating panels  6150 ′ may be varied so that the number of the first heat exchanging pipes  62  that can be accommodated in each heat exchanging chamber  613 ′ can also be varied. 
     Referring to  FIG. 24  of the drawings, the second water collection basin  71 ′ according to the alternative mode of the air conditioning system is illustrated. Like the first water collection basin  61 ′ as described above, the second water collection basin  71 ′ further comprises a supporting member  7140 ′ securely mounted at a lower portion thereof, a plurality of top separating panels  711 ′ spacedly extended from a top ceiling  7130 ′ of the second water collection basin  71 ′, and a plurality of bottom separating panels  7150 ′ spacedly and upwardly extended from the supporting member  7140 ′ to divide the second heat exchanging compartment  712 ′ into a plurality of heat exchanging chambers  713 ′. 
     As shown in  FIG. 24  of the drawings, the piping groups of the second heat exchanging pipes  72  are received in the heat exchanging chambers  713 ′ respectively. The leftmost heat exchanging chamber  713 ′ is formed between the inner sidewall  714 ′ and the leftmost top separating panel  711 ′. The second heat exchanging chamber  713 ′ is formed between the leftmost separating panel  711 ′ and the adjacent bottom separating panel  7150 ′ which is extended from the supporting member  7140 ′. The next heat exchanging chamber  713 ′ is formed between the bottom separating panel  7150 ′ and the next top separating panel  711 ′. The next heat exchanging chamber  713 ′ is formed between the top separating panel  711 ′ and the next bottom separating panel  7150 ′. The last heat exchanging chamber  713 ′ is formed between the bottom separating panel  7150 ′ and an outer sidewall  715 ′ of the second water collection basin  71 ′. 
     In other words, apart from the two side heat exchanging chambers  713 ′ (i.e. the leftmost heat exchanging chamber  713 ′ and the rightmost heat exchanging chamber  713 ′), each of the remaining heat exchanging chambers  713 ′ is defined by one top separating panel  715 ′ and an adjacent bottom separating panel  715 ′, wherein each of the piping groups of the second heat exchanging pipes  72  is received in one of the heat exchanging chambers  713 ′. 
     As a result, the cooling water entering the second heat exchanging compartment  712 ′ via the second water channel  713  is forced or guided to flow through each of the heat exchanging chambers  713 ′ and the corresponding second heat exchanging pipes  72 . It is worth mentioning that a length of the supporting member  7140 ′ is less than that of the heat exchanging compartment  712 ′ so that the rightmost heat exchanging chamber  713 ′ is formed between the rightmost bottom separating panel  7150 ′ and the second outer sidewall  715 ′. After passing through the last heat exchanging chamber  713 ′, the cooling water is then guided to flow through the second bottom plate  717 ′ and the second water distributing panel  710 ′. The temperature of the cooling water leaving the heat exchanging compartment  712 ′ is increased to a predetermined amount so as to maximize the heat exchanging efficiency between the cooling water and the ambient air in the second fill material unit  73 ′. 
     Referring to  FIG. 25  to  FIG. 26  of the drawings, according to the alternative mode of the present invention, the first cooling unit  6 ′ further comprises a first guiding system  64 ′ connected to the first heat exchanging pipes  62 ′ for guiding the refrigerant to flow through the first heat exchanging pipes  62 ′ in a predetermined order. Specifically, the first guiding system  64 ′ comprises a first inlet collection pipe  641 ′ and a first guiding pipe  642 ′, wherein each of the first heat exchanging pipes  62 ′ has one end connected to first inlet collection pipe  641 ′, and another end connected to the first guiding pipe  642 ′. 
     As shown in  FIG. 25  of the drawings, the first inlet collection pipe  641 ′ has a first fluid inlet  6411 ′, a first fluid outlet  6412 ′, and a plurality of dividers  6413 ′ provided in the first inlet collection pipe  641 ′ to divide the first heat exchanging pipes  62 ′ into a plurality of piping groups. The dividers  6413 ′ in the first inlet collection pipe  641 ′ divides it into an inlet portion  6414 ′, an outlet portion  6415 ′, and one intermediate portion  6416 ′. Each divider  6413 ′ prevents fluid from passing from one side of the divider  6413 ′ to the other side of the corresponding divider  6413 ′. The first fluid inlet  6411 ′ is formed on the first inlet portion  6414 ′, while the first fluid outlet  6412 ′ is formed on the first outlet portion  6415 ′. One divider  6413 ′ is also provided in the first guiding pipe  642 ′ to evenly divide the first guiding pipe  642 ′ into two portions. 
     In this alternative mode, there are altogether ten first heat exchanging pipes  62 ′ which are divided into four piping groups. The first piping group us constituted by three first heat exchanging pipes  62 ′. The second piping group is constituted by the next three first heat exchanging pipes  62 ′. The third piping group is constituted by the next two first heat exchanging pipes  62 ′. The last piping group is constituted by the final two first heat exchanging pipes  62 ′. The refrigerant enters the first inlet collection pipe  641 ′ through the first fluid inlet  6411 ′. Three of the first heat exchanging pipes  62 ′ (the first piping group) are connected to the first inlet portion  6414 ′, while five of the first heat exchanging pipes  62  are connected to the intermediate portion  6416 ′ (the second and the third piping group). The remaining two first heat exchanging pipes  62 ′ (the fourth piping group) are connected to the first outlet portions  6415 ′. The refrigerant entering the first inlet collection pipe  641 ′ is guided to flow through the three heat exchanging pipes  62 ′ (the first piping group) which are connected to the first inlet portion  6414 ′. The refrigerant then leaves the three first heat exchanging pipes  62 ′ and enters the first guiding pipe  642 ′. The refrigerant flowing in the first guiding pipe  642 ′ is guided by the divider  6413 ′ in the first guiding pipe  642 ′ to enter three subsequent first heat exchanging pipes  62 ′ (the second piping group) which are connected to the intermediate outlet portion  6415 ′. The refrigerant re-enters the first inlet collection pipe  641 ′ and is then guided to flow through the next two first heat exchanging pipes  62 ′ which are connected to the intermediate portion  6416 ′ (the third piping group). The refrigerant re-enters the first guiding pipe  642 ′ and is then guided to flow through the final two of the first heat exchanging pipes  62 ′ which are connected to the first outlet portion  6415 ′ (the fourth piping group). The refrigerant then exits the first inlet collection pipe  641 ′ through the first fluid outlet  6412 ′. As in the preferred embodiment described above, the refrigerant flowing through the first heat exchanging pipes  62 ′ are arranged to perform heat exchange with the cooling water passing through the first cooling unit  6 . 
     As shown in  FIG. 26  of the drawings, the first guiding system  64 ′ further comprises a plurality of first heat exchanging fins  623 ′ extended between each two adjacent first heat exchanging pipes  62 ′ for substantially increasing a surface area of heat exchange between the first heat exchanging pipes  62 ′ and the cooling water, and for reinforcing a structural integrity of the first guiding system  64 ′. These first heat exchanging fins  623 ′ may be integrally extended from an outer surface of the first heat exchanging pipes  62 ′, or externally attached or welded on the outer surfaces of the first heat exchanging pipes  62 ′. 
     Referring to  FIG. 27  to  FIG. 28  of the drawings, according to the alternative mode of the present invention, the second cooling unit  7  further comprises a second guiding system  74 ′ connected to the second heat exchanging pipes  72 ′ for guiding the refrigerant to flow through the second heat exchanging pipes  72 ′ in a predetermined order. Specifically, the second guiding system  74 ′ comprises a second inlet collection pipe  741 ′ and a second guiding pipe  742 ′, wherein each of the second heat exchanging pipes  72 ′ has one end connected to second inlet collection pipe  741 ′, and another end connected to the second guiding pipe  742 ′. 
     As shown in  FIG. 27  of the drawings, the second inlet collection pipe  741 ′ has a second fluid inlet  7411 ′, a second fluid outlet  7412 ′, and a plurality of dividers  7413 ′ provided in the second inlet collection pipe  741 ′ and the second guiding pipe  742 ′ to divide the second heat exchanging pipes  72 ′ into a plurality of piping groups. The dividers  7413 ′ in the second inlet collection pipe  741 ′ divides the second inlet collection pipe  741 ′ into an inlet portion  7414 ′, an outlet portion  7415 ′, and one intermediate portion  7416 ′. Each dividers  7413 ′ prevents fluid from passing from one side of the divider  7413 ′ to the other side of the corresponding divider  7413 ′. The second fluid inlet  7411 ′ is formed on the second inlet portion  7414 ′, while the second fluid outlet  7412 ′ is formed on the second outlet portion  7415 ′. One divider  7413 ′ is also provided in the second guiding pipe  742 ′ to evenly divide the second guiding pipe  742 ′ into two portions. 
     In this alternative mode, there are altogether ten second heat exchanging pipes  72 ′ which are divided into four piping groups. The second piping group is constituted by three second heat exchanging pipes  72 ′. The second piping group is constituted by the next three second heat exchanging pipes  72 ′. The third piping group is constituted by the next two second heat exchanging pipes  72 ′. The last piping group is constituted by the final two second heat exchanging pipes  72 ′. The refrigerant enters the second inlet collection pipe  741 ′ through the second fluid inlet  7411 ′. Three of the second heat exchanging pipes  72 ′ (the first piping group) are connected to the second inlet portion  7414 ′, while five of the second heat exchanging pipes  72 ′ are connected to the intermediate portion  7416 ′ (the second and the third piping group). The remaining two second heat exchanging pipes  72 ′ (the fourth piping group) are connected to the second outlet portions  7415 ′. The refrigerant entering the second inlet collection pipe  741 ′ is guided to flow through the three heat exchanging pipes  72 ′ (the first piping group) which are connected to the second inlet portion  7414 ′. The refrigerant then leaves the three second heat exchanging pipes  72 ′ and enters the second guiding pipe  742 ′. The refrigerant flowing in the second guiding pipe  742 ′ is guided by the corresponding divider  7413 ′ in the second guiding pipe  742 ′ to enter three subsequent second heat exchanging pipes  72 ′ (the second piping group) which are connected to the intermediate outlet portion  7415 ′. The refrigerant re-enters the second inlet collection pipe  741 ′ and is then guided to flow through the next two second heat exchanging pipes  72 ′ which are connected to the intermediate portion  7416 ′ (the third piping group). The refrigerant re-enters the second guiding pipe  742 ′ and is then guided to flow through the final two of the second heat exchanging pipes  72 ′ which are connected to the second outlet portion  7415 ′ (the fourth piping group). The refrigerant then exits the second inlet collection pipe  741 ′ through the second fluid outlet  7412 ′. As in the preferred embodiment described above, the refrigerant flowing through the second heat exchanging pipes  72 ′ are arranged to perform heat exchange with the cooling water passing through the second cooling unit  7 . 
     As shown in  FIG. 27  of the drawings, the second guiding system  74 ′ further comprises a plurality of second heat exchanging fins  723 ′ extended between each two adjacent second heat exchanging pipes  72 ′ for substantially increasing a surface area of heat exchange between the second heat exchanging pipes  72 ′ and the cooling water, and for reinforcing a structural integrity of the second guiding system  74 ′. These second heat exchanging fins  723 ′ may be integrally extended from an outer surface of the second heat exchanging pipes  72 ′, or externally attached or welded on the outer surfaces of the second heat exchanging pipes  72 ′. 
     In the alternative mode, for both the first cooling unit  6  and the second cooling unit  7 , the number of dividers  6413 ′,  7413 ′ may be varied so as to direct the flow of the refrigerant through the first heat exchanging pipes  62 ′ and the second heat exchanging pipes  72 ′ in any predetermined manner. 
     Referring to  FIG. 28  of the drawings, for each of the cooling units, the cooling water is guided to flow from the fourth piping group to the first piping group while the refrigerant is flowing from the first piping group to the fourth piping group. This arrangement ensures maximum heat exchange efficiency between the refrigerant and the cooling water. The first through fourth piping groups may accommodate in the fourth through first heat exchanging chambers. 
     Referring to  FIG. 29  of the drawings, a block diagram of the air conditioning system according to the preferred embodiment of the present invention is illustrated. The air conditioning system comprises the compressor unit  1 , the water heater  3 , the evaporative cooling system  200 , the evaporator unit  2 , a plurality of filter devices  400 , and a plurality of expansion valves  500 . The refrigerant circulates through the compressor unit  1 , the water heater  3 , an evaporator unit  2 , the evaporative cooling system  200 , the filter units  400 , and the expansion valves  500  in the manner as shown in  FIG. 29 . 
     Specifically, steam or vaporous refrigerant leaves the compressor unit  1  through a compressor outlet  105 . The compressor unit  1  is connected to the water heater  3 . The refrigerant is guided to flow into the water heater  3  for extracting a predetermined amount of heat to incoming water so that the water in the water heater  3  is heated for being delivered to users of the present invention. The refrigerant then leaves the water heater  3  and enters the evaporative cooling system  200  which is connected to the water heater  3 . The refrigerant is cooled by the evaporative cooling system  200  in the manner described above. The refrigerant then leaves the evaporative cooling system  200  and is arranged to flow through the filter devices  400 , the expansion valves  500 , and enter the evaporator unit  2  through an evaporator inlet  201 . The refrigerant in the evaporator unit  2  is arranged to absorb heat from a space in which it is located and then leaves the evaporator unit  2  through an evaporator outlet  202 . The refrigerant is then guided to flow back to the compressor unit  1  through a compressor inlet  106 . 
     It is important to mention that in the specific system shown in  FIG. 29 , the air conditioning system is capable of producing cooled air and hot water. However, the water heater  3  in the above system is optional and the refrigerant coming from the compressor unit  1  may be guided to enter the evaporator cooling system  200  without passing through any water heater  3 . This configuration is within the scope of the present invention. 
     The present invention, while illustrated and described in terms of a preferred embodiment and several alternatives, is not limited to the particular description contained in this specification. Additional alternative or equivalent components could also be used to practice the present invention.