PATENT ABSTRACT
Disclosed is a method and device for a refrigerant-based thermal energy storage and cooling system with multiple condensing units utilizing a common evaporator coil. The disclosed embodiments provide a refrigerant-based ice storage system with increased reliability, lower cost components, and reduced power consumption and ease of installation.

PATENT DESCRIPTION
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application is based upon and claims the benefit of U.S. provisional application No. 61/029,156, entitled “Thermal Energy Storage and Cooling System Utilizing Multiple Refrigerant and Cooling Loops with a Common Evaporator Coil”, filed Feb. 15, 2008, the entire disclosure of which is hereby specifically incorporated by reference for all that it discloses and teaches. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    With the increasing demands on peak demand power consumption, ice storage has been utilized to shift air conditioning power loads to off-peak times and rates. A need exists not only for load shifting from peak to off-peak periods, but also for increases in air conditioning unit capacity and efficiency. Current air conditioning units having energy storage systems have had limited success due to several deficiencies, including reliance on water chillers that are practical only in large commercial buildings and have difficulty achieving high-efficiency. In order to commercialize advantages of thermal energy storage in large and small commercial buildings, thermal energy storage systems must have minimal manufacturing costs, maintain maximum efficiency under varying operating conditions, have minimal implementation and operation impact and be suitable for multiple refrigeration or air conditioning applications. 
         [0003]    Systems for providing thermal stored energy have been previously contemplated in U.S. Pat. No. 4,735,064, U.S. Pat. No. 5,225,526, both issued to Harry Fischer, U.S. Pat. No. 5,647,225 issued to Fischer et al., U.S. Pat. No. 7,162,878 issued to Narayanamurthy et al., U.S. patent application Ser. No. 11/112,861 filed Apr. 22, 2005 by Narayanamurthy et al., U.S. patent application Ser. No. 11/138,762 filed May 25, 2005 by Narayanamurthy et al., U.S. patent application Ser. No. 11/208,074 filed Aug. 18, 2005 by Narayanamurthy et al., U.S. patent application Ser. No. 11/284,533 filed Nov. 21, 2005 by Narayanamurthy et al., U.S. patent application Ser. No. 11/610,982 filed Dec. 14, 2006 by Narayanamurthy, U.S. patent application Ser. No. 11/837,356 filed Aug. 10, 2007 by Narayanamurthy et al., and U.S. Patent Application No. 60/990,685 filed Nov. 28, 2007 by Narayanamurthy et al. All of these patents utilize ice storage to shift air conditioning loads from peak to off-peak electric rates to provide economic justification and are hereby incorporated by reference herein for all they teach and disclose. 
       SUMMARY OF THE INVENTION 
       [0004]    An embodiment of the present invention may therefore comprise a refrigerant-based thermal energy storage and cooling system comprising: a first refrigerant loop containing a first refrigerant comprising: a first condensing unit, the first condensing unit comprising a first compressor and a first condenser; a first expansion device connected downstream of the first condensing unit; and, a primary heat exchanger connected between the first expansion device and the first condensing unit that acts as an evaporator and is located within a tank filled with a fluid capable of a phase change between liquid and solid, the primary heat exchanger that facilitates heat transfer from the first refrigerant from the first condenser to cool the fluid and to freeze at least a portion of the fluid within the tank; a second refrigerant loop containing a second refrigerant comprising: a second condensing unit, the second condensing unit comprising a second compressor and a second condenser; a second expansion device connected downstream of the second condensing unit; and, a load heat exchanger connected between the second expansion device and the second condensing unit; an isolating heat exchanger that facilitates thermal contact between the cooled fluid and the second refrigerant thereby reducing the enthalpy of the second refrigerant and that returns warmed fluid to the tank. 
         [0005]    An embodiment of the present invention may also comprise a refrigerant-based thermal energy storage and cooling system comprising: a first refrigerant loop containing a first refrigerant comprising: a first condensing unit, the first condensing unit comprising a first compressor and a first condenser; a first expansion device connected downstream of the first condensing unit; and, a primary heat exchanger connected between the first expansion device and the first condensing unit that acts as an evaporator and is located within a tank filled with a fluid capable of a phase change between liquid and solid, the primary heat exchanger that facilitates heat transfer from the first refrigerant from the first condenser to cool the fluid and to freeze at least a portion of the fluid within the tank; a second refrigerant loop containing a second refrigerant comprising: a second condensing unit, the second condensing unit comprising a second compressor and a second condenser; a second expansion device connected downstream of the second condensing unit; and, a load heat exchanger connected between the second expansion device and the second condensing unit; a cooling loop containing a heat transfer material comprising: an isolating heat exchanger that facilitates thermal contact between the cooled fluid and the heat transfer material and that returns warmed fluid to the tank; and, a sub-cooling heat exchanger that facilitates thermal contact between the heat transfer material and the second refrigerant thereby reducing the enthalpy of the second refrigerant and that returns warmed heat transfer material to the isolating heat exchanger. 
         [0006]    An embodiment of the present invention may also comprise a refrigerant-based thermal energy storage and cooling system comprising: a first refrigerant loop containing a first refrigerant comprising: a first condensing unit, the first condensing unit comprising a first compressor and a first condenser; a first expansion device connected downstream of the first condensing unit; and, a primary heat exchanger connected between the first expansion device and the first condensing unit that acts as an evaporator and is located within a tank filled with a fluid capable of a phase change between liquid and solid, the primary heat exchanger that facilitates heat transfer from the first refrigerant from the first condenser to cool fluid and to freeze at least a portion of the fluid within the tank; a second refrigerant loop containing a second refrigerant comprising: a second condensing unit, the second condensing unit comprising a second compressor and a second condenser; and, a second expansion device connected downstream of the second condensing unit; a cooling loop containing a heat transfer material comprising: a first isolating heat exchanger that facilitates thermal contact between the cooled fluid and the heat transfer material and that returns warmed fluid to the tank; a second isolating heat exchanger that facilitates thermal contact between the second refrigerant and the heat transfer material and that returns warmed second refrigerant to the second compressor; and, a load heat exchanger that transfers cooling capacity of the heat transfer material to the heat load. 
         [0007]    An embodiment of the present invention may also comprise a refrigerant-based thermal energy storage and cooling system comprising: a first refrigerant loop containing a first refrigerant comprising: a first condensing unit, the first condensing unit comprising a first compressor and a first condenser; a first expansion device connected downstream of the first condensing unit; and, a primary heat exchanger connected between the first expansion device and the first condensing unit that acts as an evaporator and is located within a first tank filled with a first fluid capable of a phase change between liquid and solid, the primary heat exchanger that facilitates heat transfer from the first refrigerant from the first condenser to cool the first fluid and to freeze at least a portion of the first fluid within the first tank; a second refrigerant loop containing a second refrigerant comprising: a second condensing unit, the second condensing unit comprising a second compressor and a second condenser; a second expansion device connected downstream of the second condensing unit; and, a secondary heat exchanger connected between the second expansion device and the second condensing unit that acts as an evaporator and is located within a second tank filled with a second fluid capable of a phase change between liquid and solid, the secondary heat exchanger that facilitates heat transfer from the second refrigerant from the second condenser to cool second fluid and to freeze at least a portion of the second fluid within the second tank; a cooling loop containing a heat transfer material comprising: a first isolating heat exchanger that facilitates thermal contact between the cooled first fluid and the heat transfer material and that returns warmed first fluid to the first tank; a second isolating heat exchanger that facilitates thermal contact between the cooled second fluid and the heat transfer material and that returns warmed second fluid to the second tank; and, a load heat exchanger that transfers cooling capacity of the heat transfer material to the heat load. 
         [0008]    An embodiment of the present invention may also comprise a method of providing cooling with a thermal energy storage and cooling system comprising the steps of: compressing and condensing a first refrigerant with a first air conditioner unit to create a first high-pressure refrigerant; expanding the first high-pressure refrigerant; providing cooling to a primary heat exchanger with the first refrigerant in the primary heat exchanger that is constrained within a tank containing a fluid capable of a phase change between liquid and solid; freezing a portion of the fluid and forming ice and cooled fluid within the tank during a first time period; compressing and condensing a second refrigerant with a second air conditioner unit to create a second high-pressure refrigerant; and, expanding the second high-pressure refrigerant in a load heat exchanger to provide load cooling during a second time period; transferring cooling from the cooled fluid to the second refrigerant in the second refrigerant loop; and, transferring cooling from the second refrigerant to the load heat exchanger to provide load cooling during a third time period. 
         [0009]    An embodiment of the present invention may also comprise a method of providing cooling with a thermal energy storage and cooling system comprising the steps of: compressing and condensing a first refrigerant with a first air conditioner unit to create a first high-pressure refrigerant; expanding the first high-pressure refrigerant; providing cooling to a primary heat exchanger with the first refrigerant in the primary heat exchanger that is constrained within a tank containing a fluid capable of a phase change between liquid and solid; freezing a portion of the fluid and forming ice and cooled fluid within the tank during a first time period; compressing and condensing a second refrigerant with a second air conditioner unit to create a second high-pressure refrigerant; and, expanding the second high-pressure refrigerant in a load heat exchanger to provide load cooling during a second time period; transferring cooling from the cooled fluid to a heat transfer material in a cooling loop; transferring cooling from the heat transfer material to the second refrigerant after the second refrigerant leaves the second air conditioner thereby reducing the enthalpy of the second refrigerant; and expanding the second high-pressure refrigerant in the load heat exchanger to provide load cooling during a third time period. 
         [0010]    An embodiment of the present invention may also comprise a method of providing cooling with a thermal energy storage and cooling system comprising the steps of: compressing and condensing a first refrigerant with a first air conditioner unit to create a first high-pressure refrigerant; expanding the first high-pressure refrigerant; providing cooling to a primary heat exchanger with the first refrigerant in the primary heat exchanger that is constrained within a tank containing a fluid capable of a phase change between liquid and solid; and, freezing a portion of the fluid and forming ice and cooled fluid within the tank during a first time period; compressing and condensing a second refrigerant with a second air conditioner unit to create a second high-pressure refrigerant; expanding the second high-pressure refrigerant; transferring cooling from the second refrigerant to a heat transfer material in a cooling loop; and, transferring cooling from the heat transfer material to a load heat exchanger to provide load cooling during a second time period; transferring cooling from the cooled fluid to the heat transfer material in the cooling loop; and, transferring cooling from the heat transfer material to the load heat exchanger to provide load cooling during a third time period. 
         [0011]    An embodiment of the present invention may also comprise a method of providing cooling with a thermal energy storage and cooling system comprising the steps of: compressing and condensing a first refrigerant with a first air conditioner unit to create a first high-pressure refrigerant; expanding the first high-pressure refrigerant; providing cooling to a primary heat exchanger with the first refrigerant in the primary heat exchanger that is constrained within a first tank containing a first fluid capable of a phase change between liquid and solid; and, freezing a portion of the first fluid and forming a first ice and a first cooled fluid within the first tank during a first time period; compressing and condensing a second refrigerant with a second air conditioner unit to create a second high-pressure refrigerant; expanding the second high-pressure refrigerant; and, providing cooling to a secondary heat exchanger with the second refrigerant in the secondary heat exchanger that is constrained within a second tank containing a second fluid capable of a phase change between liquid and solid; and, freezing a portion of the second fluid and forming a second ice and a second cooled fluid within the second tank during a second time period; transferring cooling from the first refrigerant to a heat transfer material in a cooling loop; and, transferring cooling from the heat transfer material to a load heat exchanger to provide load cooling during a third time period; transferring cooling from the second refrigerant to the heat transfer material in the cooling loop; and, transferring cooling from the heat transfer material to the load heat exchanger to provide load cooling during a fourth time period. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    In the drawings, 
           [0013]      FIG. 1  illustrates an embodiment of a thermal energy storage and cooling system with multiple condensing units utilizing a common evaporator coil. 
           [0014]      FIG. 2  illustrates a configuration of another embodiment of a thermal energy storage and cooling system with multiple condensing units utilizing a common evaporator coil. 
           [0015]      FIG. 3  illustrates an embodiment of a thermal energy storage and cooling system with multiple condensing units utilizing a common evaporator coil with a sub-cooled secondary cooling loop. 
           [0016]      FIG. 4  illustrates a configuration of an embodiment of a thermal energy storage and cooling system with multiple condensing units utilizing a common evaporator coil with an isolated thermal storage unit and a sub-cooled secondary cooling loop. 
           [0017]      FIG. 5  illustrates a configuration of an embodiment of a thermal energy storage and cooling system with multiple condensing units utilizing a common evaporator coil with an isolated thermal storage unit and isolated secondary refrigerant loop. 
           [0018]      FIG. 6  illustrates another configuration of an embodiment of a thermal energy storage and cooling system with multiple condensing units utilizing a common evaporator coil with isolated primary and secondary cooling loops. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0019]    While this invention is susceptible to embodiment in many different forms, it is shown in the drawings, and will be described herein in detail, specific embodiments thereof with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not to be limited to the specific embodiments described. 
         [0020]      FIG. 1  illustrates an embodiment of a thermal energy storage and cooling system with multiple condensing units utilizing a common evaporator coil. This embodiment may function with or without an accumulator vessel or URMV  146  (universal refrigerant management vessel), and is depicted in  FIG. 1  with the vessel in place in the primary refrigerant loop with the first air conditioner unit # 1   102  and without in the URMV in the secondary refrigerant loop with the second air conditioner unit # 2   103 . As illustrated in  FIG. 1 , a first air conditioner unit # 1   102  utilizes a compressor  110  to compress cold, low pressure refrigerant gas to hot, high-pressure gas. Next, a condenser  111  removes much of the heat in the gas and discharges the heat to the atmosphere. The refrigerant leaves the condenser  111  as a warm, high-pressure liquid refrigerant delivered through a high-pressure liquid supply line  112  to the refrigerant management and distribution system  104 , which includes an expansion device  130  and to an optional accumulator vessel or URMV  146  acting as a collector and phase separator of multi-phase refrigerant. This expansion device  130  may be a conventional or non-conventional thermal expansion valve, a mixed-phase regulator and surge vessel (reservoir), or the like. Liquid refrigerant is then transferred from the URMV  146  to the thermal energy storage unit  106 . A primary heat exchanger  160  within an insulated tank  140  expands the refrigerant that is fed from a lower header assembly  156  through the freezing/discharge coils  142 , to the upper header assembly  154 . Low-pressure vapor phase and liquid refrigerant is then returned to the URMV  146  and compressor  110  via low pressure return line  118  completing the primary refrigeration loop. 
         [0021]    As illustrated in  FIG. 1 , the thermal energy storage unit  106  comprises an insulated tank  140  that houses the primary heat exchanger  160  surrounded by a liquid phase material  152  and/or solid phase material  153  (fluid/ice depending on the current system mode). The primary heat exchanger  160  further comprises a lower header assembly  156  connected to an upper header assembly  154  with a series of freezing and discharge coils  142  to make a fluid/vapor loop within the insulated tank  140 . The upper and lower header assemblies  154  and  156  communicate externally of the thermal energy storage unit  106  with inlet and outlet connections. 
         [0022]    The embodiment illustrated in  FIG. 1  utilizes the air conditioner unit # 1   102  as the principal cooling source for the thermal energy storage unit  106 . This portion of the disclosed embodiment functions in two principal modes of operation, ice-make (charging) and ice-melt (cooling) mode. 
         [0023]    In ice-make mode, compressed high-pressure refrigerant leaves the air conditioner unit # 1   102  through high-pressure liquid supply line  112  and is fed through an expansion device  130  and URMV  146  to cool the thermal energy storage unit  106  where it enters the primary heat exchanger  160  through the lower header assembly  156  and is then distributed through the freezing coils  142  which act as an evaporator. Cooling is transmitted from the freezing coils  142  to the surrounding liquid phase material  152  that is confined within the insulated tank  140  and may produce a block of solid phase material  153  (ice) surrounding the freezing coils  142  and storing thermal energy in the process. Warm liquid and vapor phase refrigerant leaves the freezing coils  142  through the upper header assembly  154  and exits the thermal energy storage unit  106  returning to the URMV  146  and then to the air conditioner unit # 1   102  through the low pressure return line  118  and is fed to the compressor  110  and re-condensed into liquid by condenser  111 . 
         [0024]    In ice-melt mode, the entirety of the fluid is not frozen within the insulated tank  140 , and therefore, an amount of fluid (liquid phase material  152 ) continuously surrounds the block of ice (solid phase material  153 ). At the bottom of the tank, this fluid is very near the freezing point of the medium and this liquid phase material  152  is propelled by a thermosiphon, or optional pump  121 , to a primary side of an isolating heat exchanger  162  where cooling is transferred to a secondary side containing a secondary cooling loop. Warm liquid phase material  152  is then returned to an upper portion of the insulated tank  140  where it is again cooled by the medium within the tank. 
         [0025]    The secondary side of the isolating heat exchanger  162  contains refrigerant and warm vapor or liquid/vapor mixture that is cooled by the primary side leaves the heat exchanger where it is optionally received/stored in a refrigerant receiver  190  and propelled by thermosiphon or optional refrigerant pump  120  through a check valve (CV- 2 )  166  and to a load heat exchanger  122  where cooling is transferred to a load. Upon leaving the load heat exchanger  122 , the warm refrigerant returns through a check valve CV- 1   164  to the secondary side of the isolating heat exchanger  162  where it is again cooled. The check valve (CV- 1 )  164  may contain a capillary by-pass  165  to assist in refrigerant charge balancing and pressure equalization in the return line to the isolating heat exchanger  162 . 
         [0026]    Additional cooling is provided within the embodiment of  FIG. 1  by a second air conditioner unit # 2   103  that utilizes an additional compressor  114  to compress cold, low pressure refrigerant gas to hot, high-pressure gas. Next, a condenser  116  removes much of the heat in the gas and discharges the heat to the atmosphere. The refrigerant leaves the condenser  116  as a warm, high-pressure liquid refrigerant delivered through a high-pressure liquid line  113 . Liquid refrigerant is then transferred to the load heat exchanger  122  through a check valve CV- 3   168  to an expansion valve  170 . This expansion device  170  can be either a conventional thermal expansion device (TXV), an electronic expansion device (EEV) or a like pressure regulating device. 
         [0027]    When cooling is being supplied from the thermal energy storage unit  106 , the check valve  168  CV- 3  acts to prevent backflow through the expansion valve  170 . Upon leaving the expansion valve  170 , refrigerant flows to the load heat exchanger  122  where cooling is transferred to a cooling load. Warm vapor or liquid/vapor mixture leaves load heat exchanger  122  and is fed through suction line  119  past a solenoid valve (SV- 1 )  180  back to air conditioner # 2   103  and is fed to the compressor  114  and re-condensed into liquid by condenser  116 . The function of the (SV- 1 )  180  is to prevent backflow through the suction line  119  when the thermal energy storage unit  106  is operating. 
         [0028]    Upon leaving the load heat exchanger  122 , the temperature of the refrigerant may be sensed with a temperature sensor  172  that is in communication with expansion valve  170 . The temperature of the refrigerant at this sensing point may act as a feedback and regulation mechanism in combination with the expansion valve  170 . If the temperature sensor  172  senses that the refrigerant temperature is too high then the expansion valve  170  will respond by producing an increased rate of expansion of the compressed refrigerant. Conversely, if the temperature sensor  172  senses that the refrigerant temperature is too low, then the expansion valve  170  will respond by producing a reduced rate of expansion of the compressed refrigerant. In this way, the amount of cooling transmitted to the cooling load is regulated. 
         [0029]    The additional loops with (SV- 2 ) and capillary bypass are intended for refrigerant balancing in various modes. When air conditioner # 2   103  is providing cooling, often the pressure in suction line  119  is lower than in the isolating heat exchanger  162 . Hence, (CV- 1 )  164  serves to prevent backflow of a large quantity of refrigerant to compressor  114 . Capillary bypass  165  serves to equalize the suction line pressure between  119  and the isolating heat exchanger  162  during ice make to ensure that all refrigerant is not drained from air conditioner # 2   103 . 
         [0030]    The additional cooling provided by the second air conditioner unit # 2   103  can replace, augment, or supplement space cooling driving either of the ice make or ice melt modes that are driven by the first air conditioner unit # 1   102 . For example, the system may be in ice-make mode with the first air conditioner unit # 1   102  transferring cooling to the thermal energy storage unit  106 , wile the second air conditioner unit # 2   103  is either off, or with the second air conditioner unit # 2   103  providing cooling to the thermal energy storage unit  106  or the load heat exchanger  122 . Additionally, the system may be in ice-melt mode with the first air conditioner unit # 1   102  off, and with cooling being provided to the load heat exchanger  122  from the thermal energy storage unit  106 . In this situation, the second air conditioner unit # 2   103  is either off, or the second air conditioner unit # 2   103  may provide additional direct cooling to the load heat exchanger  122  thereby augmenting the amount of cooling that is being provided by the thermal energy storage unit  106 . Finally, the system may be in ice-make/direct cooling mode with the first air conditioner unit # 1   102  in ice-make mode by transferring cooling to the thermal energy storage unit  106  while the second air conditioner unit # 2   103  is providing direct cooling to the load heat exchanger  122 . In this way, a wide variety of cooling responses can be delivered by a single system in order to meet various cooling, environmental, and economic variables. 
         [0031]    This variability may be further extended by specific sizing of the compressor and condenser components within the system. By having one large and one small air conditioner unit (typically conventional off-the-shelf of retrofit components), precise loads can be matched by a combination of modes to provide greater efficiency to the cooling of the system. Additionally, the two air conditioner units can be conventional packaged units, for example, as a conventional single roof-top unit with each of the units within the single housing providing the first air conditioner unit # 1   102  and the second air conditioner unit # 2   103 . 
         [0032]    The embodiment illustrated in  FIG. 2  shows a thermal energy storage unit  106  that operates using an independent refrigerant loop that transfers the cooling between the air conditioner unit # 1   102  and the thermal energy storage unit  106 . This embodiment may function with or without an accumulator vessel or URMV  146  (universal refrigerant management vessel), and is depicted in  FIG. 2  with the vessel in the primary refrigerant loop. In this example, acting as a collector and phase separator of multi-phase refrigerant, the accumulator or universal refrigerant management vessel (URMV)  146 , is in fluid communication with both the thermal energy storage unit  106  and the air conditioner unit  102 . 
         [0033]    This embodiment functions in four principal modes of operation: ice-make (charging), ice-melt (cooling), ice-melt/boost (high capacity cooling), and bypass mode. Ice-make mode in the primary refrigerant loop utilizing air conditioner unit # 1   102  is identical to that of  FIG. 1 . 
         [0034]    In ice-melt mode, the entirety of the fluid is not frozen within the insulated tank  140 , and therefore, an amount of fluid (liquid phase material  152 ) continuously surrounds the block of ice (solid phase material  153 ). At the bottom of the tank, this fluid is very near the freezing point of the medium and this liquid phase material  152  is propelled by a thermosiphon, or optional pump  121  to a primary side of an isolating heat exchanger  162  where cooling is transferred to a secondary side containing a secondary cooling loop. Warm liquid phase material  152  is then returned to an upper portion of the insulated tank  140  where it is again cooled by the medium within the tank. 
         [0035]    The secondary side of the isolating heat exchanger  162  contains refrigerant and warm vapor or liquid/vapor mixture that is cooled by the primary side leaves the heat exchanger where it is propelled by thermosiphon or optional refrigerant pump  120  through a 3-way valve (3WV- 2 )  188  and to a load heat exchanger  122  where cooling is transferred to a load. Upon leaving the load heat exchanger  122 , the warm or vapor phase refrigerant returns through a 3-way valve (3WV- 1 )  186  to the secondary side of the isolating heat exchanger  162  where it is again cooled. 
         [0036]    In ice-melt/boost (high capacity cooling) mode, the primary refrigerant loop driven by air conditioner unit # 1   102  can again continue to cool, can be shut down, or can be disengaged (valves not shown). In addition to the cooling provided by ice-melt from the thermal energy storage unit  106 , air conditioner unit # 2   103  may operate to additionally boost the cooling provided to the load heat exchanger  122 . When in operation, air conditioner unit # 2   103  utilizes a compressor  114  to compress cold, low pressure refrigerant gas to hot, high-pressure gas. Next, a condenser  116  removes much of the heat in the gas and discharges the heat to the atmosphere. The refrigerant leaves the condenser  116  as a warm, high-pressure liquid refrigerant delivered through a high-pressure liquid line  113  through an optional refrigerant receiver  190  and solenoid valve (SV- 1 )  180  to an expansion valve  170 . Like expansion device  130 , this second expansion device  170  may be a conventional or non-conventional thermal expansion valve, a mixed-phase regulator and surge vessel (reservoir) or the like. 
         [0037]    Refrigerant is metered and regulated by expansion valve  170  and transferred to a 3-way valve  188 . Upon leaving the 3-way valve  188 , refrigerant flows to the load heat exchanger  122  where cooling is transferred to a cooling load. Warm vapor or liquid/vapor mixture refrigerant leaves the load heat exchanger  122  where the temperature of the refrigerant is sensed with a temperature sensor  172  that is in communication with expansion valve  170 . The temperature of the refrigerant at this sensing point acts as a feedback and regulation mechanism in combination with the expansion valve  170  thereby controlling the amount of cooling transmitted to the cooling load. 
         [0038]    The refrigerant is then controlled by 3-way valve (3WV- 1 )  186  that directs the refrigerant to either the suction line  119 , back to air conditioner # 2   103  where it is fed to the compressor  114  and re-condensed into liquid by condenser  116 , and/or to the secondary side of the isolating heat exchanger  162 . 
         [0039]    With both the thermal energy storage unit  106  and air conditioner unit # 2   103  operating in conjunction, a very high cooling capacity is realized within the system. This boost mode may be accomplished with shared refrigerant lines as depicted in  FIG. 2 , or with a separate set of refrigerant lines (not shown) where the isolating heat exchanger  162  (cooled by the thermal energy storage unit  106 ) and air conditioner unit # 2   103  may be independently plumbed into and out of the load heat exchanger  122 . This type of embodiment would also be favorable to a load heat exchanger that contains multiple cooling coils or a mini-split evaporator. 
         [0040]    Additionally, the system may also be run in bypass mode where air conditioner unit # 2   103  may operate without the assistance of either the thermal energy storage unit  106  or air conditioner unit # 1   102  to supply conventional air conditioning to the load heat exchanger  122 . 
         [0041]      FIG. 3  illustrates an embodiment of a thermal energy storage and cooling system with multiple condensing units utilizing a common evaporator coil with a sub-cooled secondary cooling loop. As with the embodiment of  FIGS. 1 and 2 , this embodiment may function with or without an accumulator vessel or URMV  146  (universal refrigerant management vessel) on the primary refrigerant loop, and is depicted in  FIG. 3  with the vessel in place. This embodiment functions in three principal modes of operation: ice-make (charging), ice-melt/sub-cool (high capacity cooling) mode and bypass mode. Ice-make mode in the primary refrigerant loop utilizing air conditioner unit # 1   102  is identical to that of  FIG. 1 . 
         [0042]    In ice-melt/sub-cool (high capacity cooling) mode, the primary refrigerant loop driven by air conditioner unit # 1   102  can again continue to cool, or can be shut down. In this embodiment, the cooling provided by ice-melt from the thermal energy storage unit  106  is used to sub-cool the refrigerant that leaves air conditioner # 2   103  thereby increasing the cooling capacity of the refrigerant and in effect increasing the cooling capacity of air conditioner # 2   103 . 
         [0043]    In this mode, the entirety of the fluid is not frozen within the insulated tank  140 , and therefore, an amount of fluid (liquid phase material  152 ) continuously surrounds the block of ice (solid phase material  153 ). At the bottom of the tank, this fluid is very near the freezing point of the medium and this liquid phase material  152  is propelled by a thermosiphon or optional pump  120  to a primary side of a sub-cooling heat exchanger  163  where cooling is transferred to the secondary side of the heat exchanger. Cooling is transferred to the secondary side of the sub-cooling heat exchanger  163  and returned to the secondary side of the isolating heat exchanger  162  where it is again cooled. The secondary side of a sub-cooling heat exchanger  163  is refrigerant that has been compressed and condensed by air conditioner # 2   103  and fed through liquid line  113  through and optional refrigerant receiver  190  and solenoid valve (SV- 1 )  180 . Once cooling is transferred from the thermal energy storage unit  106  to the refrigerant produced by air conditioner unit # 2   103 , the sub-cooled refrigerant is fed to the expansion device  131 . 
         [0044]    Sub-cooled refrigerant is metered and regulated by expansion device  131  and transferred to the load heat exchanger  122  where cooling is transferred to a cooling load. Warm vapor or liquid/vapor mixture refrigerant leaves the load heat exchanger  122  and is then fed back via suction line  119  to air conditioner # 2   103  where it is fed to the compressor  114  and re-condensed into liquid by the condenser  116 . 
         [0045]    In bypass mode, the air conditioner # 2   103  is operating but the sub cooling heat exchanger  163  is not utilized to provide sub-cooling to the refrigerant leaving the air conditioner # 2   103  and the system acts as a conventional air conditioning system. During this bypass period, air conditioner # 1   103  may be operating to charge the thermal energy storage unit  106  (ice make) or be switched off. 
         [0046]      FIG. 4  illustrates an embodiment of a thermal energy storage and cooling system with multiple condensing units utilizing a common evaporator coil with an isolated secondary refrigerant loop. As with the embodiment of  FIG. 1 , this embodiment may function with or without an accumulator vessel or URMV  146  (universal refrigerant management vessel) on the primary refrigerant loop, and is depicted in  FIG. 4  with the vessel in place. This embodiment functions in three principal modes of operation: ice-make (charging), ice-melt/sub-cool (high capacity cooling) mode and bypass mode. Ice-make mode in the primary refrigerant loop utilizing air conditioner unit # 1   102  is identical to that of  FIG. 1 . 
         [0047]    In ice-melt/sub-cool (high capacity cooling) mode, the primary refrigerant loop driven by air conditioner unit # 1   102  can continue to cool, can be shut down, or can be disengaged. In this embodiment, the cooling provided by ice-melt from the thermal energy storage unit  106  is used to sub-cool the refrigerant that leaves air conditioner # 2   103  via an isolating heat exchanger  162  and sub-cooling heat exchanger  163 , thereby increasing the cooling capacity of the refrigerant and in effect increasing the cooling capacity of air conditioner # 2   103 . 
         [0048]    In this mode, the entirety of the fluid is not frozen within the insulated tank  140 , and therefore, an amount of fluid (liquid phase material  152 ) continuously surrounds the block of ice (solid phase material  153 ). At the bottom of the tank, this fluid is very near the freezing point of the medium and this liquid phase material  152  is propelled by a thermosiphon or optional pump  121  to a primary side of an isolating heat exchanger  162  where cooling is transferred to secondary side containing a sub-cooling loop. Warm liquid phase material  152  is then returned to an upper portion of the insulated tank  140  where it is again cooled by the medium within the tank. 
         [0049]    The sub-cooling loop on the secondary side of the isolating heat exchanger  162  contains a heat transfer material (refrigerant or coolant) that is cooled by the primary side of the isolating heat exchanger  162 . This heat transfer material is propelled in the loop by a thermosiphon or optional pump  120  to a primary side of a sub-cooling heat exchanger  163  where cooling is transferred to the secondary side of the sub-cooling heat exchanger  163 . Cooling is transferred to the secondary side of the sub-cooling heat exchanger  163  and returned to the secondary side of the isolating heat exchanger  162  where it is again cooled. The secondary side of a sub-cooling heat exchanger  163  is in thermal communication with a secondary refrigerant loop where refrigerant is compressed and condensed by air conditioner # 2   103  and fed through liquid line  113  through and optional refrigerant receiver  190  and solenoid valve (SV- 1 )  180 . Once cooling is transferred from the thermal energy storage unit  106  to the refrigerant in the secondary refrigerant loop downstream of air conditioner unit # 2   103 , the sub-cooled refrigerant is fed to the expansion device  131 . 
         [0050]    Sub-cooled refrigerant is metered and regulated by expansion device  131 . This expansion device  131  may be a conventional or non-conventional thermal expansion valve, a mixed-phase regulator and surge vessel (reservoir) or the like. Upon leaving expansion device  131 , refrigerant flows to the load heat exchanger  122  where cooling is transferred to a cooling load. Warm vapor or liquid/vapor mixture refrigerant leaves the load heat exchanger  122  and is returned via the suction line  119 , back to air conditioner # 2   103  where it is fed to the compressor  114  and re-condensed into liquid by condenser  116 . 
         [0051]    In Bypass mode the air conditioner # 2   103  operates without the influence of sub-cooling from the thermal energy storage unit  106 . In this mode, air conditioner unit # 1   102  can continue to make ice, can be shut down, or can be disengaged by valves not shown. 
         [0052]      FIG. 5  illustrates an embodiment of a thermal energy storage and cooling system with multiple condensing units utilizing a common evaporator coil with an isolated load cooling loop. As with the embodiment of  FIG. 1 , this embodiment may function with or without an accumulator vessel or URMV  146  (universal refrigerant management vessel) on the primary refrigerant loop, and is depicted in  FIG. 5  with the vessel in place for the primary refrigerant loop with air conditioner # 1   102  supplying cooling to the thermal energy storage unit  106 . This embodiment functions in four principal modes of operation: ice-make (charging), ice-melt (cooling), ice-melt/boost (high capacity cooling), and isolated bypass mode. Ice-make mode in the primary refrigerant loop utilizing air conditioner unit # 1   102  is identical to that of  FIG. 1 . 
         [0053]    In ice-melt mode, the entirety of the fluid is not frozen within the insulated tank  140 , and therefore, an amount of fluid (liquid phase material  152 ) continuously surrounds the block of ice (solid phase material  153 ). At the bottom of the tank, this fluid is very near the freezing point of the medium and this liquid phase material  152  is propelled by a thermosiphon or optional pump  121  to a primary side of an isolating heat exchanger  162  where cooling is transferred to a secondary side containing a load cooling loop  190 . Warm liquid phase material  152  is then returned to an upper portion of the insulated tank  140  where it is again cooled by the medium within the tank. 
         [0054]    A heat transfer material (refrigerant or coolant) that is cooled by the primary side of the isolating heat exchanger  162  loop is propelled within the load cooling loop  190  by thermosiphon or optional pump  120  to a load heat exchanger  122  where cooling is transferred to a load. Warm fluid, vapor or liquid/vapor mixture refrigerant or coolant leaves load heat exchanger  122  where it is returned to the secondary side of this isolating heat exchanger  162  where it is again cooled by the primary side of this isolating heat exchanger  162  being fed by the thermal energy storage unit  106  which draws cooling from by the medium within the tank. 
         [0055]    In ice-melt/boost (high capacity cooling) mode, the primary refrigerant loop driven by air conditioner unit # 1   102  can again continue to cool, can be shut down, or can be disengaged (valves not shown). In addition to the cooling provided by ice-melt from the thermal energy storage unit  106 , air conditioner unit # 2   103  may operate to additionally boost the cooling provided to the load heat exchanger  122 . When in operation, air conditioner unit # 2   103  produces refrigerant that leaves the condenser  116  as a warm, high-pressure liquid delivered through a high-pressure liquid line  113  through an optional refrigerant receiver  190  and solenoid valve (SV- 1 )  180  to an expansion device  131  and then through a primary side of an isolating heat exchanger  174 . After transferring cooling to the secondary side of the isolating heat exchanger  165  warm refrigerant/coolant returns to the air conditioner unit # 2   103  via suction line  119 . Here the refrigerant is compressed by compressor  114  and condensed by condenser  116 . This expansion device  131  may be a conventional or non-conventional thermal expansion valve, a mixed-phase regulator and surge vessel (reservoir) or the like. 
         [0056]    Refrigerant is metered and regulated by the expansion device  131  and transfers cooling from the primary side of the isolating heat exchanger  174  to the secondary side. A heat transfer material (refrigerant or coolant) flowing on the secondary side of the isolating heat exchanger  174  on the load cooling loop  190  is driven by thermosiphon or optional pump  120  to the load heat exchanger  122  where cooling is transferred to a cooling load. Warm liquid, vapor or liquid/vapor mixture refrigerant or coolant leaves the load heat exchanger  122  and returns to the isolating heat exchanger  162  where it is cooled by the primary side of this isolating heat exchanger  162  being fed by the thermal energy storage unit  106  which draws cooling from the medium within the tank. The heat transfer material then is returned to the other isolating heat exchanger  174  where it is cooled again by the primary side of the heat exchanger being fed cooling from air conditioner # 2   103 . 
         [0057]    In isolated bypass mode, the primary refrigerant loop driven by air conditioner unit # 1   102  can again continue to cool, can be shut down, or can be disengaged (valves not shown). The isolating heat exchanger  162  is not transferring cooling from the thermal energy storage unit  106  and the cooling provided to the load heat exchanger  122  is solely provided by air conditioner # 2   103  via isolating heat exchanger  174 . In this case the thermal energy storage unit  106  can be disengaged (valves not shown) from heat transfer to the load cooling loop  190 . 
         [0058]      FIG. 6  illustrates an embodiment of a thermal energy storage and cooling system with two air conditioner loops and two thermal energy storage units utilizing multiple evaporator coil paths that include a common isolated evaporator coil. As with previous embodiments, this embodiment may function with or without an accumulator vessel or URMV  146  (universal refrigerant management vessel) on the primary refrigerant loop on either refrigerant management and distribution system  104 ,  105 , and is depicted in  FIG. 8  with the vessel in place for each. This embodiment functions in three principal modes of operation: ice-make (1 or 2 AC units charging); ice-melt (1 or 2 AC units cooling); and, ice-make/ice-melt (1 or 2 AC units charging, and 1 or 2 AC units cooling). 
         [0059]    Ice-make mode in the primary refrigerant loop utilizing air conditioner unit # 1   102  and/or air conditioner unit # 2   103  is identical to that of  FIG. 1 . If the air conditioner units  102  and  103  are of different sizes, the system can choose to run the appropriate air conditioners to provide as much cooling as needed for a particular load. For example if air conditioner unit # 1   102  has a 10 ton capacity, and air conditioner unit # 2   103  has a 5 ton capacity, the units may be selectively run to provide charging at 5, 10 or 15 ton capacity depending upon the charging/cooling demand at the time. These two air conditioner units can be conventional packaged units, for example, as a conventional single roof-top unit with each of the condenser units within the single housing providing the first air conditioner unit # 1   102  and the second air conditioner unit # 2   103 . 
         [0060]    In ice-melt mode, one or both thermal energy storage units  106 / 107  may be utilized for cooling. In this embodiment, the entirety of the fluid is not frozen within either insulated tank  140 , and therefore, an amount of fluid continuously surrounds the block of ice. At the bottom of the tank, this fluid is very near the freezing point of the medium and this liquid phase material  152  is propelled by a thermosiphon, or optional pump  121  to a primary side of isolating heat exchanger # 1   162  if air conditioner unit # 1   102  is operating, and/or isolating heat exchanger # 2   174 , if air conditioner unit # 2   103  is operating. Here, cooling is transferred to a secondary side containing a load cooling loop  190 . 
         [0061]    Warm a heat transfer material (refrigerant or coolant) contained in the load cooling loop  190 , is cooled by either isolating heat exchanger # 1   162 , isolating heat exchanger # 2   174  or both, and delivered by thermosiphon or optional pump  120  to a load heat exchanger  122  where cooling is transferred to a load. Upon leaving the load heat exchanger  122 , the warm refrigerant/coolant returns to the secondary side of the isolating heat exchanger/s  162  and/or  174  where it is again cooled by the primary side of this isolating heat exchanger/s  162  and/or  174  being fed by the thermal energy storage units  106 / 107  which draw cooling from the solid phase material  153  via liquid phase material  152  surrounding the coils. 
         [0062]    In ice-make/ice-melt mode, one or two AC units  102 ,  103  are charging thermal energy storage units  106 ,  107  while 1 or two isolating heat exchanger/s  162  and/or  174  are discharging/transferring cooling to the load cooling loop  190  and thus to a cooling load via load heat exchanger  122 . For example, air conditioner unit # 1   102  may be forming ice within thermal energy storage unit # 1   106 . Cooling is transferred from the thermal energy storage unit # 1   106  to the isolating heat exchanger # 1   162 , which transfers cooling to the load cooling loop  190  on the secondary side and then to the load heat exchanger  122 . During this period, air conditioner unit # 2   103  may be dormant or utilizing air conditioner unit # 2   103  to charge the second thermal energy storage unit  107 . If energy storage unit  107  has cooling capacity, it also may be utilized to cool the load cooling loop  190  via isolating heat exchanger # 2   174 . 
         [0063]    The foregoing description of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and other modifications and variations may be possible in light of the above teachings. The embodiment was chosen and described in order to best explain the principles of the invention and its practical application to thereby enable others skilled in the art to best utilize the invention in various embodiments and various modifications as are suited to the particular use contemplated. It is intended that the appended claims be construed to include other alternative embodiments of the invention except insofar as limited by the prior art.