U.S. patent application number 12/324369 was filed with the patent office on 2009-05-28 for thermal energy storage and cooling system with multiple cooling loops utilizing a common evaporator coil.
This patent application is currently assigned to Ice Energy, Inc.. Invention is credited to Donald Thomas Cook, Ramachandran Narayanamurthy, Brian Parsonnet.
Application Number | 20090133412 12/324369 |
Document ID | / |
Family ID | 40668578 |
Filed Date | 2009-05-28 |
United States Patent
Application |
20090133412 |
Kind Code |
A1 |
Narayanamurthy; Ramachandran ;
et al. |
May 28, 2009 |
THERMAL ENERGY STORAGE AND COOLING SYSTEM WITH MULTIPLE COOLING
LOOPS UTILIZING A COMMON EVAPORATOR COIL
Abstract
Disclosed is a method and device for a refrigerant-based a
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.
Inventors: |
Narayanamurthy; Ramachandran;
(Loveland, CO) ; Parsonnet; Brian; (Fort Collins,
CO) ; Cook; Donald Thomas; (Berthoud, CO) |
Correspondence
Address: |
COCHRAN FREUND & YOUNG LLC
2026 CARIBOU DR, SUITE 201
FORT COLLINS
CO
80525
US
|
Assignee: |
Ice Energy, Inc.
Windsor
CO
|
Family ID: |
40668578 |
Appl. No.: |
12/324369 |
Filed: |
November 26, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60990685 |
Nov 28, 2007 |
|
|
|
Current U.S.
Class: |
62/66 ; 62/115;
62/335; 62/79 |
Current CPC
Class: |
Y02E 60/147 20130101;
F24F 5/0017 20130101; F25B 2400/23 20130101; F25B 2400/06 20130101;
F25D 16/00 20130101; Y02E 60/14 20130101 |
Class at
Publication: |
62/66 ; 62/335;
62/115; 62/79 |
International
Class: |
F25C 1/00 20060101
F25C001/00; F25B 7/00 20060101 F25B007/00; F25B 1/00 20060101
F25B001/00 |
Claims
1. A refrigerant-based thermal energy storage and cooling system
comprising: a first refrigerant loop containing a refrigerant
comprising: a first condensing unit comprising a first compressor
and a first condenser; a first expansion device connected
downstream of said first condensing unit; and, a thermal energy
storage unit comprising a primary heat exchanger connected between
said first expansion device and said first condensing unit that
acts as a first evaporator and is located within a tank filled with
a fluid, said primary heat exchanger that facilitates heat transfer
from said first refrigerant from said first condenser to cool said
fluid within said tank; a second refrigerant loop containing
additional said refrigerant comprising a load heat exchanger
connected to said thermal energy storage unit that transfers
cooling from said thermal energy storage unit to said load heat
exchanger to a heat load; a third refrigerant loop containing
additional said refrigerant comprising: a second condensing unit
comprising a second compressor and a second condenser; and, a
second expansion device connected downstream of said second
condensing unit, and said load heat exchanger connected between
said second expansion device and said second condensing unit that
transfers cooling capacity of said second condensing unit to said
load heat exchanger to a heat load.
2. The system of claim 1 further comprising: a refrigerant
management vessel in fluid communication with, and located between
said condensing unit and said primary heat exchanger comprising: an
inlet connection that receives refrigerant from said condensing
unit and said primary heat exchanger; a first outlet connection
that supplies refrigerant to said primary heat exchanger; and, a
second outlet connection that supplies refrigerant to said
condensing unit.
3. The system of claim 1 wherein said first expansion device and
said second expansion device are chosen from the group consisting
of a thermal expansion valve, an electronic expansion valve and a
mixed-phase regulator.
4. The system of claim 1 wherein said fluid is a eutectic
material.
5. The system of claim 1 wherein said fluid is water.
6. The system of claim 1 wherein said load heat exchanger is at
least one mini-split evaporator.
7. A refrigerant-based thermal energy storage and cooling system
comprising: a first refrigerant loop containing a first refrigerant
comprising: a first condensing unit comprising a first compressor
and a first condenser; a first expansion device connected
downstream of said first condensing unit; and, a thermal energy
storage unit comprising a primary heat exchanger connected between
said first expansion device and said first condensing unit that
acts as a first evaporator and is located within a tank filled with
a fluid, said primary heat exchanger that facilitates heat transfer
from said first refrigerant from said first condenser to cool said
fluid within said tank; a primary side of an isolating heat
exchanger that draws cooling from said thermal energy storage unit
and transfers cooling to a secondary side of said isolating heat
exchanger; a second refrigerant loop containing a second
refrigerant comprising: a second condensing unit comprising a
second compressor and a second condenser; a second expansion device
connected downstream of said second condensing unit; and, a load
heat exchanger connected between said second expansion device and
said second condensing unit that transfers cooling capacity of said
second refrigerant to said heat load in a first time period, said
load heat exchanger that is connected to said secondary side of
said isolating heat exchanger and that transfers cooling from said
secondary side of said isolating heat exchanger to said heat load
in a second time period.
8. The system of claim 7 further comprising: a refrigerant
management vessel in fluid communication with, and located between
said condensing unit and said primary heat exchanger comprising: an
inlet connection that receives refrigerant from said condensing
unit and said primary heat exchanger; a first outlet connection
that supplies refrigerant to said primary heat exchanger; and, a
second outlet connection that supplies refrigerant to said
condensing unit.
9. The system of claim 7 wherein said first expansion device and
said second expansion device are chosen from the group consisting
of a thermal expansion valve, an electronic expansion valve and a
mixed-phase regulator.
10. The system of claim 7 wherein said fluid is a eutectic
material.
11. The system of claim 7 wherein said fluid is water.
12. The system of claim 7 wherein said load heat exchanger is at
least one mini-split evaporator.
13. The system of claim 7 wherein said first refrigerant is a
different material from said second refrigerant.
14. The system of claim 7 wherein said first time period is
concurrent with said second time period.
15. A refrigerant-based thermal energy storage and cooling system
comprising: a first refrigerant loop containing a refrigerant
comprising: a first condensing unit comprising a first compressor
and a first condenser; a first expansion device connected
downstream of said first condensing unit; and, a thermal energy
storage unit comprising a primary heat exchanger connected between
said first expansion device and said first condensing unit that
acts as a first evaporator and is located within a tank filled with
a fluid, said primary heat exchanger that facilitates heat transfer
from said first refrigerant from said first condenser to cool said
fluid within said tank; a primary side of a sub-cooling heat
exchanger that draws cooling from said thermal energy storage unit
and transfers cooling to a secondary side of said sub-cooling heat
exchanger; a second refrigerant loop containing additional said
refrigerant comprising: a second condensing unit comprising a
second compressor and a second condenser; said second condensing
unit that supplies said refrigerant to said secondary side of said
sub-cooling heat exchanger where cooling is transferred from said
secondary side of said sub-cooling heat exchanger to said
additional said refrigerant thereby creating sub-cooled
refrigerant; a second expansion device connected downstream of said
secondary side of said sub-cooling heat exchanger; and, a load heat
exchanger connected between said second expansion device and said
second condensing unit that transfers cooling capacity of said
sub-cooled refrigerant to said heat load in a first time period,
said load heat exchanger that is connected to said thermal energy
storage unit and that transfers cooling from said thermal energy
storage unit to said heat load in a second time period.
16. The system of claim 15 wherein said first expansion device and
said second expansion device are chosen from the group consisting
of a thermal expansion valve, an electronic expansion valve and a
mixed-phase regulator.
17. The system of claim 15 wherein said fluid is a eutectic
material.
18. The system of claim 15 wherein said fluid is water.
19. The system of claim 15 wherein said load heat exchanger is at
least one mini-split evaporator.
20. The system of claim 15 wherein said first time period is
concurrent with said second time period.
21. A refrigerant-based thermal energy storage and cooling system
comprising: a first refrigerant loop containing a first refrigerant
comprising: a first condensing unit comprising a first compressor
and a first condenser; a first expansion device connected
downstream of said first condensing unit; and, a thermal energy
storage unit comprising a primary heat exchanger connected between
said first expansion device and said first condensing unit that
acts as a first evaporator and is located within a tank filled with
a fluid, said primary heat exchanger that facilitates heat transfer
from said first refrigerant from said first condenser to cool said
fluid within said tank; a primary side of an isolating heat
exchanger that draws cooling from said thermal energy storage unit
and transfers cooling to a secondary side of said isolating heat
exchanger; a second refrigerant loop containing a second
refrigerant comprising: a second condensing unit comprising a
second compressor and a second condenser; a second expansion device
connected downstream of said second condensing unit; a primary side
of a sub-cooling heat exchanger connected between said second
expansion device and said second condenser; a secondary side of
said sub-cooling heat exchanger that draws cooling from said
secondary side of said isolating heat exchanger to sub-cool said
second refrigerant in said primary side of said sub-cooling heat
exchanger; and, a load heat exchanger that draws cooling from said
primary side of said sub-cooling heat exchanger or said secondary
side of said isolating heat exchanger and transfers cooling to a
load.
22. The system of claim 21 wherein said first expansion device and
said second expansion device are chosen from the group consisting
of a thermal expansion valve, an electronic expansion valve and a
mixed-phase regulator.
23. The system of claim 21 wherein said fluid is a eutectic
material.
24. The system of claim 21 wherein said fluid is water.
25. The system of claim 21 wherein said load heat exchanger is at
least one mini-split evaporator.
26. The system of claim 21 wherein said first refrigerant is a
different material from said second refrigerant.
27. A refrigerant-based thermal energy storage and cooling system
comprising: a first refrigerant loop containing a first refrigerant
comprising: a first condensing unit comprising a first compressor
and a first condenser; a first expansion device connected
downstream of said first condensing unit; and, a thermal energy
storage unit comprising a primary heat exchanger connected between
said first expansion device and said first condensing unit that
acts as a first evaporator and is located within a tank filled with
a fluid, said primary heat exchanger that facilitates heat transfer
from said first refrigerant from said first condenser to cool said
fluid within said tank; a second refrigerant loop containing a
second refrigerant comprising: a second condensing unit comprising
a second compressor and a second condenser; a second expansion
device connected downstream of said second condensing unit; a
primary side of a first isolating heat exchanger that draws cooling
from said thermal energy storage unit and transfers cooling to a
secondary side of said first isolating heat exchanger; a primary
side of second a isolating heat exchanger connected between said
second expansion device and said second condenser that transfers
cooling to a secondary side of said second isolating heat
exchanger; and, a load heat exchanger receives cooling from a
secondary side of said first isolating heat exchanger, or said
secondary side of said second isolating heat exchanger, or a
combination of said secondary side of said first isolating heat
exchanger and said secondary side of said second isolating heat
exchanger.
28. The system of claim 27 wherein said first expansion device and
said second expansion device are chosen from the group consisting
of a thermal expansion valve, an electronic expansion valve and a
mixed-phase regulator.
29. The system of claim 27 wherein said fluid is a eutectic
material.
30. The system of claim 27 wherein said fluid is water.
31. The system of claim 27 wherein said load heat exchanger is at
least one mini-split evaporator.
32. The system of claim 27 wherein said first refrigerant is a
different material from said second refrigerant.
33. A method of providing cooling with a refrigerant-based thermal
energy storage and cooling system comprising the steps of:
compressing and condensing a refrigerant with a first air
conditioner unit to create a first high-pressure refrigerant;
expanding said first high-pressure refrigerant to provide cooling
to a 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 said fluid and forming ice within
said tank during a first time period; cooling said refrigerant in
said primary heat exchanger with said ice and transferring said
refrigerant to a load heat exchanger to provide load cooling;
returning said refrigerant to said primary heat exchanger; and,
re-cooling said refrigerant during a second time period;
compressing and condensing said refrigerant with a second air
conditioner unit to create a second high-pressure refrigerant; and,
expanding said second high-pressure refrigerant in said load heat
exchanger to provide load cooling during a third time period.
34. The method of claim 33 further comprising the step of: managing
volumes and phase of said refrigerant with a refrigerant management
vessel, said refrigerant management vessel in fluid communication
with said first air conditioner unit and said primary heat
exchanger.
35. The method of claim 33 wherein said steps of said second time
period are performed concurrent with said steps of said third time
period.
36. A method of providing cooling with a refrigerant-based thermal
energy storage and cooling system comprising the steps of:
compressing and condensing a first refrigerant to create a first
high-pressure refrigerant; providing cooling to a primary heat
exchanger by expanding said first high-pressure refrigerant in said
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 said fluid to form ice within said tank
during a first time period; transferring cooling from said fluid
and said ice to a primary side of an isolating heat exchanger;
transferring cooling from said primary side of said isolating heat
exchanger to a second refrigerant on a secondary side of said
isolating heat exchanger; and, transferring cooling from cooled
said second refrigerant to a load heat exchanger to provide load
cooling during a second time period; compressing and condensing
said second refrigerant to create a second high-pressure
refrigerant; and, expanding said second high-pressure refrigerant
in said load heat exchanger to provide load cooling during a third
time period.
37. The method of claim 36 further comprising the step of: managing
volumes and phase of said first refrigerant with a refrigerant
management vessel, said refrigerant management vessel in fluid
communication with said first air conditioner unit and said primary
heat exchanger.
38. The method of claim 36 further comprising the step of: managing
volumes and phase of said second refrigerant with a refrigerant
receiver, said refrigerant receiver in fluid communication with
said second air conditioner unit and said isolating heat
exchanger.
39. The method of claim 36 wherein said steps of said second time
period are performed concurrent with said steps of said third time
period.
40. A method of providing cooling with a thermal energy storage and
cooling system comprising the steps of: compressing and condensing
a refrigerant with a first air conditioner unit to create a first
high-pressure refrigerant; providing cooling to a primary heat
exchanger by expanding said first high-pressure refrigerant in said
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 said fluid to form ice within said tank
during a first time period; transferring cooling from said fluid
and said ice to a load heat exchanger to provide load cooling in a
second time period; compressing and condensing said refrigerant
with a second air conditioner unit to create a second high-pressure
refrigerant; transferring cooling from said fluid and said ice to a
primary side of a sub-cooling heat exchanger; transferring said
second high-pressure refrigerant from said second air conditioner
unit to a secondary side of said sub-cooling heat exchanger;
sub-cooling said second high-pressure refrigerant by transferring
cooling from said primary side of said sub-cooling heat exchanger
to said secondary side of said sub-cooling heat exchanger;
transferring sub-cooled said second high-pressure refrigerant from
said secondary side of said isolating heat exchanger to a load heat
exchanger; expanding said sub-cooled said second high-pressure
refrigerant in said load heat exchanger to provide load cooling;
and, returning said refrigerant to said second air conditioner unit
during a third time period.
41. The method of claim 40 further comprising the step of: managing
volumes and phase of said first refrigerant with a refrigerant
management vessel, said refrigerant management vessel in fluid
communication with said first air conditioner unit and said primary
heat exchanger.
42. The method of claim 40 further comprising the step of: managing
volumes and phase of said second refrigerant with a refrigerant
receiver, said refrigerant receiver in fluid communication with
said second air conditioner unit and said sub-cooling heat
exchanger.
43. The method of claim 40 wherein said steps of said second time
period are performed concurrent with said steps of said third time
period.
44. 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; providing cooling to a primary
heat exchanger by expanding said first high-pressure refrigerant in
said 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 said fluid to form ice within
said tank during a first time period; transferring cooling from
said fluid and said ice to a primary side of a first isolating heat
exchanger; transferring cooling from said primary side of said
first isolating heat exchanger to a secondary side of said first
isolating heat exchanger; and, transferring cooling from said
secondary side of said first isolating heat exchanger to a load
heat exchanger to provide load cooling in a second time period;
compressing and condensing a second refrigerant with a second air
conditioner unit to create a second high-pressure refrigerant;
transferring cooling from said second high-pressure refrigerant to
a primary side of a second isolating heat exchanger; transferring
cooling from said primary side of said second isolating heat
exchanger to a secondary side of said second isolating heat
exchanger; and, transferring cooling from said secondary side of
said second isolating heat exchanger to said load heat exchanger to
provide load cooling in a third time period.
45. The method of claim 44 further comprising the step of: managing
volumes and phase of said first refrigerant with a refrigerant
management vessel, said refrigerant management vessel in fluid
communication with said first air conditioner unit and said primary
heat exchanger.
46. The method of claim 44 further comprising the step of: managing
volumes and phase of said second refrigerant with a refrigerant
receiver, said refrigerant receiver in fluid communication with
said second air conditioner unit and said second isolating heat
exchanger.
47. The method of claim 44 wherein said steps of said second time
period are performed concurrent with said steps of said third time
period.
48. 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; providing cooling to a first
primary heat exchanger by expanding said first high-pressure
refrigerant in said first 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
said first fluid to form first ice within said tank during a first
time period; transferring cooling from said first fluid and said
first ice to a primary side of a first isolating heat exchanger;
transferring cooling from said primary side of said first isolating
heat exchanger to a secondary side of said first isolating heat
exchanger; and, transferring cooling from said secondary side of
said first isolating heat exchanger to a load heat exchanger to
provide load cooling in a second time period; compressing and
condensing a second refrigerant with a second air conditioner unit
to create a second high-pressure refrigerant; providing cooling to
a second primary heat exchanger by expanding said second
high-pressure refrigerant in said second primary 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 said second fluid to form second ice within said second
tank during a third time period; transferring cooling from said
second fluid and said second ice to a primary side of a second
isolating heat exchanger; transferring cooling from said primary
side of said second isolating heat exchanger to a secondary side of
said second isolating heat exchanger; and, transferring cooling
from said secondary side of said second isolating heat exchanger to
said load heat exchanger to provide load cooling in a fourth time
period.
49. The method of claim 48 further comprising the step of: managing
volumes and phase of said first refrigerant with a first
refrigerant management vessel, said first refrigerant management
vessel in fluid communication with said first air conditioner unit
and said first primary heat exchanger.
50. The method of claim 48 further comprising the step of: managing
volumes and phase of said second refrigerant with a second
refrigerant management vessel, said second refrigerant management
vessel in fluid communication with said second air conditioner unit
and said second primary heat exchanger.
51. The method of claim 48 wherein said steps of said first time
period are performed concurrent with said steps of said fourth time
period.
52. The method of claim 48 wherein said steps of said second time
period are performed concurrent with said steps of said third time
period.
53. The method of claim 48 wherein said steps of said second time
period are performed concurrent with said steps of said fourth time
period.
54. A means for providing cooling with a thermal energy storage and
cooling system comprising: a first air conditioner means for
compressing and condensing a first refrigerant to create a first
high-pressure refrigerant; a means for providing cooling to a
primary heat exchanger by expanding said first high-pressure
refrigerant in said primary heat exchanger that is constrained
within a tank containing a fluid capable of a phase change between
liquid and solid; and, a means for freezing a portion of said fluid
to form ice within said tank during a first time period; a means
for transferring cooling from said first high-pressure refrigerant
to a load heat exchanger to provide load cooling during a second
time period; a means for transferring cooling from said fluid and
said ice to a load heat exchanger to provide load cooling during a
third time period; a second air conditioner means for compressing
and condensing additional said refrigerant to create a second
high-pressure refrigerant; a means for transferring cooling from
said second high-pressure refrigerant to said load heat exchanger
to provide load cooling during a fourth time period.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is based upon and claims the benefit of
U.S. provisional application No. 60/990,685, entitled "Thermal
Energy Storage and Cooling System with Multiple Cooling Loops
Utilizing a Common Evaporator Coil", filed Nov. 28, 2007, 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 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, and U.S. patent application
Ser. No. 11/837,356 filed Aug. 10, 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
refrigerant comprising: a first condensing unit comprising a first
compressor and a first condenser; a first expansion device
connected downstream of the first condensing unit; and, a thermal
energy storage unit comprising a primary heat exchanger connected
between the first expansion device and the first condensing unit
that acts as a first evaporator and is located within a tank filled
with a fluid, the primary heat exchanger that facilitates heat
transfer from the first refrigerant from the first condenser to
cool the fluid within the tank; a second refrigerant loop
containing additional refrigerant comprising a load heat exchanger
connected to the thermal energy storage unit that transfers cooling
from the thermal energy storage unit to the load heat exchanger to
a heat load; a third refrigerant loop containing additional
refrigerant comprising: a second condensing unit comprising a
second compressor and a second condenser; and, a second expansion
device connected downstream of the second condensing unit, and the
load heat exchanger connected between the second expansion device
and the second condensing unit that transfers cooling capacity of
the second condensing unit to the load heat exchanger to a heat
load.
[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 refrigerant
comprising: a first condensing unit comprising a first compressor
and a first condenser; a first expansion device connected
downstream of the first condensing unit; and, a thermal energy
storage unit comprising a primary heat exchanger connected between
the first expansion device and the first condensing unit that acts
as a first evaporator and is located within a tank filled with a
fluid, the primary heat exchanger that facilitates heat transfer
from the first refrigerant from the first condenser to cool the
fluid within the tank; a primary side of a sub-cooling heat
exchanger that draws cooling from the thermal energy storage unit
and transfers cooling to a secondary side of the sub-cooling heat
exchanger; a second refrigerant loop containing additional
refrigerant comprising: a second condensing unit comprising a
second compressor and a second condenser; the second condensing
unit that supplies the refrigerant to the secondary side of the
sub-cooling heat exchanger where cooling is transferred from the
secondary side of the sub-cooling heat exchanger to the additional
refrigerant thereby creating sub-cooled refrigerant; a second
expansion device connected downstream of the secondary side of the
sub-cooling heat exchanger; and, a load heat exchanger connected
between the second expansion device and the second condensing unit
that transfers cooling capacity of the sub-cooled refrigerant to
the heat load in a first time period, the load heat exchanger that
is connected to the thermal energy storage unit and that transfers
cooling from the thermal energy storage unit to the heat load in a
second time period.
[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 comprising a first compressor
and a first condenser; a first expansion device connected
downstream of the first condensing unit; and, a thermal energy
storage unit comprising a primary heat exchanger connected between
the first expansion device and the first condensing unit that acts
as a first evaporator and is located within a tank filled with a
fluid, the primary heat exchanger that facilitates heat transfer
from the first refrigerant from the first condenser to cool the
fluid within the tank; a second refrigerant loop containing a
second refrigerant comprising: a second condensing unit comprising
a second compressor and a second condenser; a second expansion
device connected downstream of the second condensing unit; a
primary side of a first isolating heat exchanger that draws cooling
from the thermal energy storage unit and transfers cooling to a
secondary side of the first isolating heat exchanger; a primary
side of second a isolating heat exchanger connected between the
second expansion device and the second condenser that transfers
cooling to a secondary side of the second isolating heat exchanger;
and, a load heat exchanger receives cooling from a secondary side
of the first isolating heat exchanger, or the secondary side of the
second isolating heat exchanger, or a combination of the secondary
side of the first isolating heat exchanger and the secondary side
of the second isolating heat exchanger.
[0007] An embodiment of the present invention may also comprise a
method of providing cooling with a refrigerant-based thermal energy
storage and cooling system comprising the steps of: compressing and
condensing a refrigerant with a first air conditioner unit to
create a first high-pressure refrigerant; expanding the first
high-pressure refrigerant to provide cooling to a 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 within the tank during a first
time period; cooling the refrigerant in the primary heat exchanger
with the ice and transferring the refrigerant to a load heat
exchanger to provide load cooling; returning the refrigerant to the
primary heat exchanger; and, re-cooling the refrigerant during a
second time period; compressing and condensing the refrigerant with
a second air conditioner unit to create a second high-pressure
refrigerant; and, expanding the second high-pressure refrigerant in
the load heat exchanger to provide load cooling during a third time
period.
[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 refrigerant with a first air conditioner unit to create a first
high-pressure refrigerant; providing cooling to a primary heat
exchanger by expanding the first high-pressure 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 to form ice within the tank during
a first time period; transferring cooling from the fluid and the
ice to a load heat exchanger to provide load cooling in a second
time period; compressing and condensing the refrigerant with a
second air conditioner unit to create a second high-pressure
refrigerant; transferring cooling from the fluid and the ice to a
primary side of a sub-cooling heat exchanger; transferring the
second high-pressure refrigerant from the second air conditioner
unit to a secondary side of the sub-cooling heat exchanger;
sub-cooling the second high-pressure refrigerant by transferring
cooling from the primary side of the sub-cooling heat exchanger to
the secondary side of the sub-cooling heat exchanger; transferring
sub-cooled the second high-pressure refrigerant from the secondary
side of the isolating heat exchanger to a load heat exchanger;
expanding the sub-cooled the second high-pressure refrigerant in
the load heat exchanger to provide load cooling; and, returning the
refrigerant to the second air conditioner unit during a third time
period.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] In the drawings,
[0010] FIG. 1 illustrates an embodiment of a thermal energy storage
and cooling system with multiple condensing units utilizing a
common evaporator coil.
[0011] FIG. 2 illustrates an embodiment of a thermal energy storage
and cooling system with multiple condensing units utilizing a
common evaporator coil with an isolated primary refrigerant
loop.
[0012] FIG. 3 illustrates a configuration of another embodiment of
a thermal energy storage and cooling system with multiple
condensing units utilizing a common evaporator coil.
[0013] 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 primary
refrigerant loop.
[0014] FIG. 5 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 refrigerant
loop.
[0015] FIG. 6 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 primary
refrigerant loop and a sub-cooled secondary refrigerant loop.
[0016] FIG. 7 illustrates a 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 refrigerant loops.
[0017] FIG. 8 illustrates another configuration of an embodiment of
multiple thermal energy storage and cooling systems with multiple
condensing units utilizing a common evaporator coil with isolated
primary and secondary refrigerant loops.
DETAILED DESCRIPTION OF THE INVENTION
[0018] 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.
[0019] 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 (universal refrigerant
management vessel), and is depicted in FIG. 1 with the vessel. 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 an expansion device 130 and to an 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 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 refrigeration loop.
[0020] 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 change material 152
and/or solid phase change 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.
[0021] 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.
[0022] 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 change material 152 that is
confined within the insulated tank 140 and may produce a block of
solid phase change 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.
[0023] In ice-melt mode, cool liquid refrigerant leaves the lower
portion of the insulated tank 140 via lower header assembly 156 and
is propelled by a thermosiphon or optional pump 120 through a check
valve (CV-2) 166 to a load heat exchanger 122 where cooling is
transferred to a load (i.e., with the aid of an air handler not
shown). Warm vapor or liquid/vapor mixture leaves load heat
exchanger 122 where the liquid is returned through another check
valve (CV- 1) 164 to the upper header assembly 154 of the thermal
energy storage unit 106 and draws cooling from the solid phase
change material 153 and or liquid phase change material 152
surrounding the coils. 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 primary heat
exchanger 160.
[0024] 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.
[0025] 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.
[0026] Upon leaving the load heat exchanger 122, 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. 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. The embodiment
illustrated in FIG. 1 additionally shows an optional pressure
equalization line 174 that acts to balance the pressure in the
refrigerant loop which includes air conditioner #2 103 and load
heat exchanger 122.
[0027] 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 upper header 154. 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 154 during ice make to ensure
that all refrigerant is not drained from air conditioner #2 103. In
the same way, (SV-2) 182 is activated by a low pressure signal on
the suction line 119 to transfer larger amounts of refrigerant from
the thermal energy storage unit 106 to the air conditioner #2 103
when it is providing cooling to the load heat exchanger 122.
[0028] 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 (direct expansion [DX]) 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.
[0029] 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, 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 packaged, 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.
[0030] FIG. 2 illustrates an embodiment of a thermal energy storage
and cooling system with multiple condensing units utilizing a
common evaporator coil with an isolated primary refrigerant loop.
As with the embodiment of FIG. 1, this embodiment may function with
or without an accumulator vessel or URMV (universal refrigerant
management vessel), and is depicted in FIG. 2 with the vessel in
place. As illustrated in FIG. 2, 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 an expansion device 130 and to an
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 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 refrigeration
loop.
[0031] As was illustrated in FIG. 1, the thermal energy storage
unit 106 of FIG. 2 comprises an insulated tank 140 that houses the
primary heat exchanger 160 surrounded by a liquid phase change
material 152 and/or solid phase change 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.
[0032] The embodiment illustrated in FIG. 2 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.
[0033] 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 change material 152 that is
confined within the insulated tank 140 and may produce a block of
solid phase change 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.
[0034] In ice-melt mode, cool liquid refrigerant leaves the lower
portion of the insulated tank 140 via lower header assembly 156 and
is propelled by a thermosiphon or optional pump 121 to a primary
side of an isolating heat exchanger 162 where cooling is
transferred to the secondary side of this isolating heat exchanger
162 and to a secondary refrigerant loop. Warmed refrigerant is then
returned from the primary side of the isolating heat exchanger 162
back to the thermal energy storage unit 106 where it is cooled
again. Refrigerant that is cooled by the primary refrigerant loop
is propelled in the secondary refrigerant loop by a thermosiphon or
optional pump 120 through a check valve (CV-2) 166 to a load heat
exchanger 122 where cooling is transferred to a load (i.e., with
the aid of an air handler not shown).
[0035] Warm vapor or liquid/vapor mixture leaves load heat
exchanger 122 where it is returned through another check valve
(CV-1) 164 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 the solid phase change material 153 and or
liquid phase change material 152 surrounding the coils. 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. Additionally, this
refrigerant may contain a refrigerant receiver 190 within the loop
to act as a surge vessel and reservoir for maintaining proper
levels of refrigerant within this loop.
[0036] In a similar manner to the embodiment of FIG. 1, additional
cooling may be provided within the embodiment of FIG. 2 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 to the load heat exchanger 122 through a check valve CV-3 168
to an expansion device 170. This expansion device 170 may be a
conventional or non-conventional thermal expansion valve (TXV), an
electronic expansion device (EEV), a mixed-phase regulator and
surge vessel (reservoir) or the like.
[0037] 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 refrigerant leaves the load heat exchanger 122 and is fed
through suction line 119 back to air conditioner #2 103 and is fed
to the compressor 114 and re-condensed into liquid by condenser
116. The function of valve (SV-1) 180 is to prevent backflow
through the suction line 119 when the thermal energy storage unit
106 is operating.
[0038] Upon leaving the load heat exchanger 122, 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. As with FIG.
1, the additional loops with (SV-2) and capillary bypass are
intended for refrigerant balancing in various modes.
[0039] The additional cooling provided by the second air
conditioner unit #2 103 can replace or augment cooling of the ice
melt mode that are driven by the first air conditioner unit #1 102.
For example, 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
via isolation heat exchanger 162. 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 (DX) cooling
to the load heat exchanger 122 thereby augmenting the amount of
cooling that is being provided by the thermal energy storage unit
106. Additionally, 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 wile
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.
[0040] The isolation heat exchanger 162 provides additional control
and refrigerant management to the overall system by reducing the
line volumes and path length variability that can be seen in the
embodiment of FIG. 1. Additionally, since the primary and secondary
refrigerant loops are isolated from one another, different
refrigerants may be used within each loop of the system. For
example, one type of highly efficient refrigerant that may have
properties that would discourage use within a dwelling (such as
propane) may be utilized within the primary refrigerant loop that
is isolated by the isolating heat exchanger 162, while a more
suitable refrigerant (such as R-22 or R-410A) can be used for the
secondary refrigerant loop that may enter the dwelling. This allows
greater versatility and efficiency of the system while maintaining
safety, environmental, and application issues to be addressed.
[0041] Additionally, the isolating heat exchanger 162 may also
provide a junction point between the primary refrigerant loop that
may be located outside a structure, while the secondary refrigerant
loop is located within the structure. It is also noted that the
embodiment illustrated in FIG. 2 shows the system without the
pressure equalization line 174 that is shown in FIG. 1. In any of
the disclosed embodiments, the pressure equalization line 174 shown
in FIG. 1 may be used as an optional feature.
[0042] The embodiment illustrated in FIG. 3 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 (universal
refrigerant management vessel), and is depicted in FIG. 3 with the
vessel. 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.
[0043] This embodiment functions in five principal modes of
operation: ice-make (charging), ice-melt (cooling), ice-melt/boost
(high capacity cooling), ice-make/boost (high capacity charging)
and bypass mode. Ice-make mode in the primary refrigerant loop
utilizing air conditioner unit #1 102 is identical to that of FIG.
1.
[0044] In ice-melt only (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 (valves not shown). Cool
liquid refrigerant is drawn from the thermal energy storage unit
106 and is transported by thermosiphon or pumped by a liquid pump
120 through a 3-way valve 188 to the load heat exchanger 122 where
cooling is transferred to a load. The warm mixture of liquid and
vapor phase refrigerant leaves the load heat exchanger 122 where
the mixture is returned to the thermal energy storage unit 106 now
acting as a condenser, through a 3-way valve 186. Vapor phase
refrigerant is cooled and condensed by drawing cooling from the
cold fluid or ice where it becomes again available for load
cooling.
[0045] 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 131 may be a conventional
or non-conventional thermal expansion valve, a mixed-phase
regulator and surge vessel (reservoir) or the like.
[0046] 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.
[0047] 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
thermal energy storage unit 106. Valve 165 is placed on a separate
charge equalization line between the two outlet lines of 3-way
valve (3WV-1) 186 to enable refrigerant to migrate from the thermal
energy storage unit 106 to air conditioner #2 103 and vice versa.
Since the thermal energy storage unit 106 is usually the coldest
location in the system, the refrigerant will likely migrate to the
thermal energy storage unit during idle periods and will need to be
returned to the air conditioning unit #2 103 during its
operation.
[0048] 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.
3, or with a separate set of refrigerant lines (not shown) where
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.
[0049] In ice-make/boost (high capacity charging) mode, air
conditioner unit #2 103 supplies refrigerant that is metered and
regulated by expansion valve 170 (temperature sensor 172
deactivated) and transferred to the 3-way valve 188. Upon leaving
the 3-way valve 188, refrigerant flows to the thermal energy
storage unit 106 (bypassing pump 120) 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 change material 152 that is confined
within the insulated tank 140 and may produce a block of solid
phase change 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
and proceeds to 3-way valve (3WV-1) 186 that returns the
refrigerant to air conditioner unit #2 103 through suction line
119. In this mode, both air conditioner units may act to rapidly
deliver cooling to the thermal energy storage unit 106 and produce
thermal energy storage within a short time.
[0050] 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.
[0051] FIG. 4 illustrates an embodiment (similar to that detailed
in FIG. 3) of a thermal energy storage and cooling system with
multiple condensing units utilizing a common evaporator coil with
an isolated primary refrigerant loop. As with the embodiment of
FIG. 3, this embodiment may function with or without an accumulator
vessel or URMV (universal refrigerant management vessel), and is
depicted in FIG. 4 with the vessel in place. This embodiment also
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.
[0052] In ice-melt only (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 (valves not shown). Cool
liquid refrigerant is drawn from the thermal energy storage unit
106 and is transported by thermosiphon or optionally pumped by a
liquid pump 121 to a primary side of an isolating heat exchanger
162 where cooling is transferred to the secondary side of the
isolating heat exchanger 162. Warm refrigerant is then returned to
the thermal energy storage unit 106 where it is cooled by the solid
phase change material 153 and/or the liquid phase change material
152 that are in thermal contact with the primary heat exchanger
160.
[0053] Refrigerant within the secondary side of the isolating heat
exchanger 162 is cooled by the primary side and flows by
thermosiphon or optional pump 120 through a 3-way valve 188 to load
heat exchanger 122 where cooling is transferred from the
refrigerant to a load. The warm mixture of liquid and vapor phase
refrigerant leaves the load heat exchanger 122 where the mixture is
returned to the secondary side of the isolating heat exchanger 162
now acting as a condenser, through a 3-way valve 186. Vapor phase
refrigerant is cooled and condensed by drawing cooling from the
primary side of the isolating heat exchanger 162 where it becomes
again available for load cooling.
[0054] 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 131 may be a conventional
or non-conventional thermal expansion valve, a mixed-phase
regulator, and surge vessel (reservoir) or the like.
[0055] 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.
[0056] The refrigerant is then controlled by 3-way valve 186 that
directs the refrigerant to enter 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.
[0057] 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.
4, or with a separate set of refrigerant lines (not shown) where
the thermal energy storage unit 106 and air conditioner unit #2 103
may be independently pumped 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.
[0058] 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 (via the
isolating heat exchanger 162) or air conditioner unit #1 102 to
supply conventional air conditioning to the load heat exchanger
122.
[0059] As with the embodiments described in FIGS. 2 and 3, the
isolation heat exchanger 162 provides additional control and
refrigerant management to the overall system by reducing the line
volumes and path length variability that can be seen in the
embodiment of FIG. 4. Additionally, since the primary and secondary
refrigerant loops are isolated from one another, different
refrigerants maybe used within each loop of the system.
[0060] FIG. 5 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 refrigerant
loop. As with the embodiment of FIG. 4, this embodiment may
function with or without an accumulator vessel or URMV (universal
refrigerant management vessel) on the primary refrigerant loop, and
is depicted in FIG. 5 with the vessel in place. This embodiment
functions in five principal modes of operation: ice-make
(charging), ice-melt (cooling), ice-melt/boost (high capacity
cooling), 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.
[0061] In ice-melt only (cooling) mode, the cooling loop utilizing
the thermal storage unit 106 is similar to that of FIG. 3. In this
mode, the primary refrigerant loop driven by air conditioner unit
#1 102 can continue to cool, can be shut down, or can be disengaged
(valves not shown). Cool liquid refrigerant is drawn from the
thermal energy storage unit 106 and is transported by thermosiphon
or pumped by an optional liquid pump 120 through two 3-way valves
189 and 188 to the load heat exchanger 122 where cooling is
transferred to a load. The warm mixture of liquid and vapor phase
refrigerant leaves the load heat exchanger 122 where the mixture is
returned to the thermal energy storage unit 106 now acting as a
condenser, through a third 3-way valve 186. Vapor phase refrigerant
is cooled and condensed by drawing cooling from the cold fluid or
ice where it becomes again available for load cooling.
[0062] 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, 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 through a secondary side of a sub-cooling
heat exchanger 163 and then to an expansion device 131. Like
expansion device 130, this second expansion device 131 may be a
conventional or non-conventional thermal expansion valve, a
mixed-phase regulator and surge vessel (reservoir) or the like.
[0063] Refrigerant is metered and regulated by expansion device 13
land 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 and is then
controlled by 3-way valve 186 that directs the refrigerant to 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.
[0064] 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, can be shut down, or can be disengaged
(valves not shown). 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.
[0065] In this mode, cool liquid refrigerant leaves the lower
portion of the insulated tank 140 via lower header assembly 156 and
is propelled by a thermosiphon or optional pump 120 through a 3-way
valve (3WV-3) 189 to a primary side of a sub-cooling heat exchanger
163 where cooling is transferred to the secondary side of the heat
exchanger. The secondary side of a sub-cooling heat exchanger 163
is a 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 check 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.
[0066] Sub-cooled refrigerant is metered and regulated by expansion
device 131 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
and is then controlled by 3-way valve 186 that directs the
refrigerant to 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. Subcooling increases the capacity of the
refrigeration loop without increasing the size of the compressor.
It can also be accomplished without sharing the refrigeration
loops.
[0067] FIG. 6 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. 5, this embodiment may function with
or without an accumulator vessel or URMV (universal refrigerant
management vessel) on the primary refrigerant loop, and is depicted
in FIG. 6 with the vessel in place. This embodiment functions in
five principal modes of operation: ice-make (charging), ice-melt
(cooling), ice-melt/boost (high capacity cooling),
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.
[0068] In ice-melt mode, cool liquid refrigerant leaves the lower
portion of the insulated tank 140 via lower header assembly 156 and
is propelled by a thermosiphon or optional pump 121 to a primary
side of an isolating heat exchanger 162 where cooling is
transferred to the secondary side of this isolating heat exchanger
162 and to a secondary refrigerant loop. Warmed refrigerant is then
returned from the primary side of the isolating heat exchanger 162
back to the thermal energy storage unit 106 where it is cooled
again. Refrigerant that is cooled by the primary side of the
isolating heat exchanger 162 loop is propelled in the secondary
refrigerant loop by a thermosiphon or optional pump 120 through a
3-way valve (3WV-3) 189 and then through another 3-way valve
(3WV-2) 188 to a load heat exchanger 122 where cooling is
transferred to a load.
[0069] Warm vapor or liquid/vapor mixture leaves load heat
exchanger 122 where it is returned through a 3-way valve (3WV-1)
186 back 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 the solid phase change material 153 and/or
liquid phase change material 152 surrounding the coils.
[0070] 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 through a secondary side of a sub-cooling heat exchanger
163 and then to an expansion device 131.
[0071] Refrigerant is metered and regulated by expansion device 13
land 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 and is then
controlled by 3-way valve 186 that directs the refrigerant to 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.
[0072] 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, 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,
thereby increasing the cooling capacity of the refrigerant and in
effect increasing the cooling capacity of air conditioner #2
103.
[0073] In this mode, cool liquid refrigerant leaves the lower
portion of the insulated tank 140 via lower header assembly 156 and
is propelled by a thermosiphon or optional pump 121 to a primary
side of an isolating heat exchanger 162 where cooling is
transferred to the secondary side of this isolating heat exchanger
162 and to a secondary refrigerant loop. Warmed refrigerant is then
returned from the primary side of the isolating heat exchanger 162
back to the thermal energy storage unit 106 where it is cooled
again. Refrigerant that is cooled by the primary side of the
isolating heat exchanger 162 loop is propelled in the secondary
refrigerant loop by a thermosiphon or optional pump 120 through a
3-way valve (3WV-3) 189 to a primary side of a sub-cooling heat
exchanger 163 where cooling is transferred to the secondary side of
the heat exchanger. The secondary side of a sub-cooling heat
exchanger 163 is a 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 check valve
(SV-1) 180. Once cooling is transferred from the thermal energy
storage unit 106 and the refrigerant is produced by air conditioner
unit #2 103, the sub-cooled refrigerant is fed to the expansion
device 131.
[0074] Sub-cooled refrigerant is metered and regulated by expansion
device 131 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
and is then controlled by 3-way valve 186 that directs the
refrigerant to 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.
[0075] FIG. 7 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
and an isolated sub-cooled second air conditioner loop. As with the
embodiment of FIG. 6, this embodiment may function with or without
an accumulator vessel or URMV (universal refrigerant management
vessel) on the primary refrigerant loop, and is depicted in FIG. 7
with the vessel in place. 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.
[0076] In ice-melt mode, cool liquid refrigerant leaves the lower
portion of the insulated tank 140 via lower header assembly 156 and
is propelled by a thermosiphon or optional pump 121 to a primary
side of an isolating heat exchanger 162 where cooling is
transferred to the secondary side of this isolating heat exchanger
162 and to a secondary refrigerant loop. Warmed refrigerant is then
returned from the primary side of the isolating heat exchanger 162
back to the thermal energy storage unit 106 where it is cooled
again. Refrigerant that is cooled by the primary side of the
isolating heat exchanger 162 loop is propelled in the secondary
refrigerant loop by a thermosiphon or optional pump 120 through a
solenoid valve (SV-2) 182 and to a load heat exchanger 122 where
cooling is transferred to a load.
[0077] Warm vapor or liquid/vapor mixture 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 the solid
phase change material 153 and/or liquid phase change material 152
surrounding the coils.
[0078] 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 165.
[0079] Refrigerant is metered and regulated by the expansion device
131 and transfers cooling from the primary side of the isolating
heat exchanger 165 to the secondary side. Refrigerant flowing on
the secondary side of the isolating heat exchanger 165 is driven by
thermosiphon or optional pump 120 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 returns through another solenoid valve (SV-3) 184 back to the
isolating heat exchanger 165 where it is cooled again by the
primary side of the heat exchanger being fed cooling from air
conditioner #2 130.
[0080] FIG. 8 illustrates an embodiment of multiple thermal energy
storage and cooling systems with two air conditioner loops and two
thermal energy storage units utilizing multiple evaporator coil
paths that include an isolated evaporator coil. As with previous
embodiments, this embodiment may function with or without an
accumulator vessel or URMV (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 four principal modes of operation, ice-make (1 or 2 AC units
charging), ice-melt (1 or 2 AC units cooling), ice-make/ice-melt (1
AC unit charging, 1 AC unit cooling). 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.
[0081] In ice-melt mode, one or both thermal energy storage units
106/107 may be utilized for cooling. In this embodiment, cool
liquid refrigerant or coolant leaves the lower portion of the
insulated tank 140 via lower header assembly 156 and is propelled
by a thermosiphon or optional pump 121/122 to a primary side of an
isolating heat exchanger 162/163 where cooling is transferred to
the secondary side of this isolating heat exchanger 162/163 and to
a secondary loop. Warmed refrigerant or coolant is then returned
from the primary side of the isolating heat exchanger 162/163 back
to the thermal energy storage unit 106 and/or 107 where it is
cooled again. Refrigerant or coolant that is cooled by the primary
side of the isolating heat exchanger 162/163 loop is propelled in
the secondary cooling loop by a thermosiphon or optional pump 120
to a load heat exchanger 122 where cooling is transferred to a
load.
[0082] Warm refrigerant or coolant leaves load heat exchanger 122
where it is returned to the secondary side of the first isolating
heat exchanger 162 where it is again cooled by the primary side of
this first isolating heat exchanger 162 being fed by the thermal
energy storage unit 106 which draws cooling from the solid phase
change material 153 and or liquid phase change material 152
surrounding the coils. The refrigerant or coolant leaves the first
isolating heat exchanger 163 and travels to the secondary side of
the second isolating heat exchanger 163 where it is again cooled by
the primary side of this second isolating heat exchanger 163 being
fed by the thermal energy storage unit 107 which draws cooling from
the solid phase change material 153 and or liquid phase change
material 152 surrounding the coils.
[0083] In ice-make/ice-melt mode, one AC unit is charging a thermal
energy storage unit while the other AC unit can either charge a
second thermal energy storage unit or can be shut down. 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 first isolating heat
exchanger 162 which transfers cooling to the cooling loop 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 #1 102 to charge the second thermal energy storage
unit 107. Thus in this embodiment, as with all the disclosed
embodiments, the time periods for charging and discharging the
thermal energy storage units and the air conditioning units is
independent of sequence and coincidence. Various "time periods"
even though referred to as a "first time period" or a "second time
period" may be concurrent or reversed in actual order that they are
performed.
[0084] 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.
* * * * *