阅读说明：本技术 混合空气冷却系统和方法 (Hybrid air cooling system and method ) 是由 克里斯托弗尔·约翰内斯·韦尔默朗 于 2020-01-31 设计创作，主要内容包括：本发明涉及一种混合空气冷却系统10,其包括用于接收主空气流14的主入口12、用于将调节空气流18供应到调节空间的主出口16以及在主入口12和主出口16之间延伸的主空气流动通道20。系统10还包括主热交换装置22,其设置在主空气流动通道20中,其适于允许主空气流14可操作地通过其中,以在主空气流14通过其中时从主空气流14中提取热能,从而形成经调节的空气流18。主热交换装置22包括利用第一冷却剂26从主空气流14中提取热能的第一间接热交换元件24,利用第二冷却剂30从主空气流14中提取热能的第二间接热交换元件28,以及利用第三冷却剂34从主空气流14中提取热能的第三直接热交换元件32。(The present invention relates to a hybrid air cooling system 10 including a primary inlet 12 for receiving a primary air stream 14, a primary outlet 16 for supplying a conditioned air stream 18 to a conditioned space, and a primary air flow passage 20 extending between the primary inlet 12 and the primary outlet 16. The system 10 further includes a primary heat exchange means 22 disposed in the primary air flow passage 20 and adapted to allow the primary air stream 14 to operatively pass therethrough to extract heat energy from the primary air stream 14 as the primary air stream 14 passes therethrough to form the conditioned air stream 18. The main heat exchange means 22 comprises a first indirect heat exchange element 24 which uses a first coolant 26 to extract thermal energy from the main air stream 14, a second indirect heat exchange element 28 which uses a second coolant 30 to extract thermal energy from the main air stream 14, and a third direct heat exchange element 32 which uses a third coolant 34 to extract thermal energy from the main air stream 14.)

1. A hybrid air cooling system (10), comprising:

-a main inlet (12) for receiving a main air flow (14), a main outlet (16) for supplying a conditioned air flow (18) to the conditioned space, and a main air flow channel (20) extending between the main inlet and the main outlet (12, 16);

-a main heat exchange means (22) disposed in the main air flow channel (20) and adapted to allow the main air stream (14) to operatively pass therethrough, the main heat exchange means (22) being operative to extract heat energy from the main air stream (14) as the main air stream (14) passes therethrough and thereby form a conditioned air stream (18) from the main air stream (14), the main heat exchange means (22) comprising:

o a first indirect heat exchange element (24) operable to extract thermal energy from the primary air stream (14) using a first coolant (26);

o a second indirect heat exchange element (28) operable to extract thermal energy from the primary air stream (14) with a second coolant (30); and

o a third direct heat exchange element (32) operable to extract thermal energy from the primary air stream (14) using a third coolant (34);

-an evaporative cooling unit (38) operative to extract thermal energy from the first coolant (26) by evaporation before the first coolant (26) is supplied to the first indirect heat exchange element (24);

-a thermal energy storage (40) operative to absorb thermal energy from the second coolant (30) before the second coolant is supplied to the second indirect heat exchange element (28); and

-a primary coolant distribution device (42) operative to distribute the tertiary coolant (34) over the third direct heat exchange element (32), whereby when the primary air stream (14) comes into contact with the tertiary coolant (34), thermal energy (34) is extracted from the primary air stream (14) and moisture from the tertiary coolant (34) is absorbed into the primary air stream (14).

2. The hybrid air-cooling system (10) of claim 1, configured to operatively cool the primary air stream (14) by extracting thermal energy from the primary air stream (14) by means of any one or more selected from the group consisting of a first indirect heat exchange element (24), a second indirect heat exchange element (28), and a third direct heat exchange element (32).

3. The hybrid air cooling system (10) of claim 1 or 2, configured to operatively cool the primary air stream (14) under first atmospheric conditions by extracting thermal energy from the primary air stream (14) by means of either or both of the first and third heat exchange elements (24, 32).

4. A hybrid air cooling system (10) according to claim 3 configured to operatively cool the primary air stream (14) by extracting thermal energy from the air stream (14) by means of the second heat exchange element (28) under second atmospheric conditions having a higher relative humidity than the first atmospheric conditions.

5. The hybrid air cooling system (10) of claim 4 configured to operatively cool the primary air stream (14) under second atmospheric conditions by extracting thermal energy from the air stream (14) by way of either or both of the first and third heat exchange elements (24, 32).

6. The mixed air cooling system (10) according to any one of the preceding claims, wherein a main coolant reservoir (74) is provided below the main heat exchange means (22) for receiving and accumulating the third coolant (34) operatively bled from the third direct heat exchange element (32), and wherein the system (10) is configured to operatively supply the third coolant (34) from the main coolant reservoir (74) to the main coolant distribution means (42).

7. The hybrid air cooling system (10) according to any one of the preceding claims, wherein the evaporative cooling unit (38) includes:

-a secondary inlet (44) for receiving a secondary air flow (46), a secondary outlet (48) for discharging an exhaust gas flow (50) from the cooling unit (38), and a secondary air flow channel (52) extending between the secondary inlet and the secondary outlet (44, 48);

-a secondary direct heat exchange element (56) disposed in the secondary air flow channel (52) and adapted to allow a secondary air flow (46) to operatively pass therethrough; and

-secondary coolant distribution means (58) for distributing the first coolant (26) over the secondary direct heat exchange element (56) so as to be operable to extract thermal energy from the first coolant (26) when the first coolant (26) is in contact with the secondary air stream (46), and moisture from the first coolant (26) is absorbed into the secondary air stream (46).

8. The hybrid air cooling system (10) of claim 7, wherein a secondary coolant reservoir (60) is provided below the secondary direct heat exchange element (56) for operatively receiving and accumulating the first coolant (26) flowing from the secondary direct heat exchange element (56).

9. The hybrid air cooling system (10) of claim 8, configured to operatively supply the first coolant (26) from the secondary coolant reservoir (60) to the first indirect heat exchange element (24), wherein thermal energy is transferred from the primary air flow (14) to the first coolant (26), and further configured to subsequently return the first coolant (26) from the first indirect heat exchange element (24) to the secondary coolant distribution device (58).

10. The hybrid air cooling system (10) of any of the preceding claims, comprising a heat transfer device (62) for receiving the second coolant (30) and operable to transfer thermal energy from the second coolant (30) to the heat sink.

11. A hybrid air cooling system (10) according to claim 10, wherein the heat transfer device (62) is in the form of a heat pump and the heat sink is the atmosphere.

12. The hybrid air cooling system (10) of any one of the preceding claims, wherein the thermal energy storage (40) comprises:

-a housing (64) in which a plurality of thermal energy storage elements (66) are stacked, each element (66) having an outer shell formed of a flexible material and filled with a thermal energy storage medium; and

-a stored coolant distribution arrangement (68) for distributing the second coolant (30) over the thermal energy storage element (66) such that thermal energy can be operatively transferred between the second coolant (30) and the thermal energy storage element (66) when the second coolant (30) flows through and in contact with the thermal energy storage element (66).

13. The hybrid air cooling system (10) according to claim 10 or 11, configured to operatively supply the second coolant (30) from the heat transfer arrangement (62) to the thermal energy storage (40), wherein the second coolant (30) absorbs thermal energy from the thermal energy storage (40) and subsequently returns the second coolant (30) to the heat transfer arrangement (62).

14. The hybrid air cooling system (10) of claim 1, configured to operatively supply a second coolant (30) from a thermal energy reservoir (40) to the second indirect heat exchange element (28), wherein thermal energy is transferred from the primary air flow (14) to the second coolant (30), and subsequently return the second coolant (30) to the thermal energy reservoir (40), wherein thermal energy is transferred from the second coolant (30) to the thermal energy reservoir (40).

15. The hybrid air cooling system (10) of claim 12, wherein the thermal energy storage medium comprises a phase change medium.

16. The hybrid air cooling system (10) of any of the preceding claims, wherein the first, second, and third heat exchange elements (24, 28, 32) are positioned in series such that the primary air flow (14) operatively passes through each of the first, second, and third heat exchange elements (24, 28, 32) as it moves from the primary inlet (12) to the primary outlet (16).

17. The hybrid air cooling system (10) of any of the preceding claims, wherein a primary blower (36) is located in the primary air flow channel (20) for inducing the primary air flow (14).

18. The hybrid air cooling system (10) of claim 7, wherein a secondary blower (54) is located in the secondary air flow channel (52) for inducing the secondary air flow (46).

19. A method of supplying a conditioned air stream (18) to a conditioned space, the method comprising the steps of, at first atmospheric conditions:

-extracting thermal energy from the first coolant (26) by evaporation;

-supplying a first coolant (26) to the first indirect heat exchange element (24);

-distributing a third coolant (34) over the third direct heat exchange element (32); and

-forcing the primary air flow (14) through the first and third heat exchange elements (24, 32), whereby thermal energy is transferred from the air flow (14) to the first coolant (26) as the air flow (14) passes through the first heat exchange element (24), and further thermal energy is extracted from the air flow (14) as the air flow (14) comes into contact with the third coolant (34) and moisture from the third coolant (34) is absorbed into the air flow (14), thereby forming a conditioned air flow (18) from the primary air flow (14);

under second atmospheric conditions:

-transferring thermal energy from the second coolant (30) to the thermal energy storage (40) by bringing the second coolant (30) in the vicinity of the storage (40) maintained at a lower operating temperature than the second coolant (30);

-supplying a second coolant (30) to the second indirect heat exchange element (28); and

-forcing the primary air flow (14) through the second heat exchange element (28), whereby heat energy is transferred from the air flow (14) to the second coolant (30) when the air flow (14) passes through the second heat exchange element (28), thereby forming a conditioned air flow (18) from the primary air flow (14).

20. The method of claim 19, comprising, at a second atmospheric condition:

-extracting thermal energy from the first coolant (26) by evaporation;

-supplying a first coolant (26) to the first indirect heat exchange element (24); and

-forcing the primary air flow (14) through the first heat exchange element (24), whereby thermal energy is transferred from the air flow (14) to the first coolant (26) when the air flow (14) passes through the first heat exchange element (24).

21. The method of claim 19, comprising, at a second atmospheric condition:

-distributing a third coolant (34) over the third direct heat exchange element (32);

-forcing the primary air flow (14) through the third heat exchange element (32), thereby extracting thermal energy from the air flow (26) and absorbing moisture from the third coolant (34) to the air flow (14) when the air flow (26) is in contact with the third coolant (34).

22. A method according to any one of claims 19-21, wherein thermal energy is transferred from the second coolant (30) to the hot trap.

23. The method of any of claims 19-22, wherein the first atmospheric condition is more favorable to evaporative cooling than the second atmospheric condition.

24. The method of any of claims 19-23, wherein the air at the first atmospheric condition has a lower relative humidity than the air at the second atmospheric condition.

25. A hybrid air-cooling system according to claim 1 substantially as described herein with reference to the accompanying drawings.

26. A method according to claim 20 substantially as herein described with reference to the accompanying drawings.

Technical Field

The invention relates to a hybrid air cooling system and method. More particularly, but not exclusively, the invention relates to a hybrid air cooling system and method capable of adjusting its operating conditions in accordance with prevailing atmospheric conditions.

Background

Hybrid air cooling systems comprising an evaporative cooling unit which cools a medium by means of liquid evaporation and a refrigeration cooling unit which draws heat from the cold medium and rejects it to a hot medium by means of a series of thermodynamic processes are well known and widely used.

Evaporative cooling units consume significantly less power during operation and are therefore more economical to operate than refrigeration cooling units. However, evaporative cooling does not operate effectively in humid conditions, since it relies on the evaporation of a liquid.

For the above reasons, the individual cooling units are often mounted together, especially in cases where large area temperature regulation is required, to take advantage of the operational advantages of both cooling units. According to this configuration, the evaporative cooling unit is mainly relied on to supply cold air to a specified area, and the refrigeration cooling unit is used only when the evaporative cooling unit cannot sufficiently supply cold air due to generally unfavorable atmospheric conditions.

A disadvantage of the above-described hybrid air cooling system is that its power consumption increases significantly when the refrigeration cooling unit is operating. It is well known that electrical service providers charge consumers not only according to the total electricity usage (typically in kilowatt-hours) over a particular time period, but also according to the peak load used during the same time period, regardless of the duration of the peak load required. The refrigeration cooling unit is a major contributor to cooling system peak load usage.

Disclosure of Invention

It is therefore an object of the present invention to provide a hybrid air cooling system and method with which the above disadvantages may be overcome or at least reduced and/or which will be a useful alternative to known hybrid air cooling systems and methods.

According to a first aspect of the present invention, there is provided a hybrid air cooling system comprising:

-a main inlet for receiving a main air flow, a main outlet for supplying a conditioned air flow to the conditioned space, and a main air flow channel extending between the main inlet and the main outlet;

-a primary heat exchange means disposed in the primary air flow path and adapted to allow the primary air stream to operatively pass therethrough, the primary heat exchange means being operable to extract thermal energy from the primary air stream as it passes therethrough and thereby form a conditioned air stream from the primary air stream, the primary heat exchange means comprising:

a first indirect heat exchange element operable to extract thermal energy from the primary air stream with the first coolant;

o a second indirect heat exchange element operable to extract thermal energy from the primary air stream with a second coolant; and

a third direct heat exchange element operable to extract thermal energy from the primary air stream using a third coolant;

-an evaporative cooling unit for extracting thermal energy from the first coolant by evaporation before the first coolant is operatively supplied to the first indirect heat exchange element;

-a thermal energy storage for absorbing thermal energy from the second coolant before the second coolant is operatively supplied to the second indirect heat exchange element; and

-primary coolant distribution means for distributing the tertiary coolant to the third direct heat exchange element, thereby efficiently extracting thermal energy from the primary air stream and absorbing moisture from the tertiary coolant to the primary air stream when the primary air stream is in contact with the tertiary coolant.

It should be understood that the hybrid air cooling system may be configured to operatively cool the primary air stream at a particular point in time by extracting thermal energy from the primary air stream by means of any one or more selected from the group consisting of the first indirect heat exchange element, the second indirect heat exchange element, and the third direct heat exchange element.

According to an exemplary embodiment of the invention, the hybrid air cooling system may be configured to operatively cool the primary air stream under first atmospheric conditions by extracting thermal energy from the primary air stream by means of either or both of the first and third heat exchange elements, and configured to operatively cool the primary air stream under second atmospheric conditions in which the first and third heat exchange elements are unable to cool the primary air stream to a desired set point temperature by extracting thermal energy from the primary air stream by means of the second indirect heat exchange element.

Thermal energy is extracted from the primary air stream by the second indirect heat exchange element in combination with, or separately from, either or both of the first and third heat exchange elements.

The first atmospheric condition is set to favor evaporative cooling over the second atmospheric condition. More specifically, air at a first atmospheric condition has a lower relative humidity than air at a second atmospheric condition. Therefore, the wet bulb pressure drop is greater at the first atmospheric condition than at the second atmospheric condition, and the wet bulb pressure drop ratio is the largest contributor to system efficiency.

A main coolant reservoir may be provided below the main heat exchange means for receiving and accumulating the third coolant flowing from the third direct heat exchange element. According to an exemplary embodiment, the system is configured to operatively supply the third coolant from the main coolant reservoir to the main coolant distribution device.

The primary coolant distribution means may comprise a primary manifold located at an operatively upper end of the third direct heat exchange element.

An evaporative cooling unit is provided comprising:

-a secondary inlet for receiving a secondary air flow, a secondary outlet for discharging an exhaust gas flow from the cooling unit, and a secondary air flow channel extending between the secondary inlet and the secondary outlet;

-a secondary direct heat exchange element disposed in the secondary air flow channel and adapted to allow a secondary air flow to operatively pass therethrough; and

-secondary coolant distribution means for distributing the first coolant over the second direct heat exchange element, thereby being operable to extract thermal energy from the first coolant and absorb moisture from the first coolant to the secondary air stream when the first coolant is in contact with the secondary air stream.

A secondary coolant reservoir may be disposed below the secondary direct heat exchange element for operatively receiving and accumulating the first coolant flowing from the secondary direct heat exchange element.

The secondary coolant distribution device may include a secondary manifold located above the secondary direct heat exchange element.

The first indirect heat exchange element is configured to include a length of tubing through which the first coolant is operable to flow and over which the primary air stream passes, whereby thermal energy is transferred from the primary air stream to the first coolant.

Preferably, the system is configured to operatively supply the first coolant from the secondary coolant reservoir to the first indirect heat exchange element, wherein thermal energy is transferred from the primary air flow to the first coolant, and is further configured to subsequently return the first coolant from the first indirect heat exchange element to the secondary coolant distribution device.

The system may also include a heat transfer device for receiving the second coolant and operable to transfer thermal energy from the second coolant to the heat sink. According to an exemplary embodiment of the invention, the heat transfer device is in the form of a heat pump and the heat sink is the atmosphere.

The system may be configured to operatively supply a second coolant from the heat transfer device to the thermal energy storage, wherein the second coolant absorbs thermal energy from the thermal energy storage, and to subsequently return the second coolant to the heat transfer device.

The thermal energy storage may comprise:

-a housing in which a plurality of thermal energy storage elements are stacked, each element having an outer shell formed of a flexible material and filled with a thermal energy storage medium; and

-a stored coolant distribution means for distributing the second coolant over the thermal energy storage element such that thermal energy can be operatively transferred between the second coolant and the thermal energy storage element when the second coolant flows through and in contact with the thermal energy storage element.

The second indirect heat exchange element is configured to include a length of tubing through which the second coolant is operable to flow and over which the primary air flow passes, whereby thermal energy is transferred from the primary air flow to the second coolant.

The system is configured such that, according to a first example operating state thereof, a second coolant is operatively supplied from the thermal energy reservoir to the second indirect heat exchange element, wherein thermal energy is transferred from the primary air flow to the second coolant. The second coolant is then returned from the second indirect heat exchange element to the thermal energy storage, wherein thermal energy is transferred from the second coolant to the thermal energy storage. More specifically, when the second coolant and the thermal energy storage element are in contact with each other, thermal energy is transferred from the second coolant to the thermal energy storage element.

Preferably, the second coolant is operatively supplied to the second indirect heat exchange element from a bottom region of the housing, and the second coolant is returned from the second indirect heat exchange element to the reservoir after thermal energy is transferred from the primary air flow to the second coolant.

The system is configured such that, according to a second example operating state thereof, the second coolant is operatively supplied from the thermal energy store to the heat transfer arrangement where thermal energy is expelled from the second coolant to the hot sink. The second coolant is then returned from the heat transfer device to the thermal energy storage, where thermal energy is transferred from the storage to the second coolant. More specifically, when the thermal energy storage element and the second coolant are in contact with each other, thermal energy is transferred from the thermal energy storage element to the second coolant.

Preferably, the thermal energy storage medium of the thermal energy storage element comprises a phase change medium, such as water.

The first, second and third heat exchange elements are arranged to be positioned in series such that the primary air flow is operable to pass through each of the first, second and third heat exchange elements as it moves from the primary inlet to the primary outlet.

A primary blower may be located in the primary air flow passage for inducing a primary air flow.

A secondary blower may be located in the secondary air flow passage for inducing a secondary air flow.

According to an exemplary embodiment of the invention, the main inlet, the main outlet, the main air flow channel and the main heat exchange device may together form a main cooling unit. The main cooling unit may be integrally connected to the evaporative cooling unit.

The first and third coolants may include water. The second coolant can include water with an additive, such as an antifreeze that lowers the freezing temperature of the second coolant.

According to a second aspect of the present invention there is provided a method of supplying a conditioned gas stream to a conditioned space, the method comprising the steps of: under first atmospheric conditions:

-extracting thermal energy from the first coolant by evaporation;

-supplying a first coolant to the first indirect heat exchange element;

-distributing a third coolant over the third direct heat exchange element; and

-forcing the primary air stream through the first and third heat exchange elements, whereby thermal energy is transferred from the air stream to the first coolant as the air stream passes through the first heat exchange element, and further thermal energy is extracted from the air stream and moisture of the third coolant is absorbed into the air stream as the air stream comes into contact with the third coolant, thereby forming a conditioned air stream from the primary air stream;

and under second atmospheric conditions:

-transferring thermal energy from the second coolant to a thermal energy storage, which is maintained at a lower operating temperature than the second coolant, by bringing the second coolant in the vicinity of the storage;

-supplying a second coolant to the second indirect heat exchange element; and

-forcing the primary air flow through the second heat exchange element, whereby heat energy is transferred from the air flow to the second coolant when the second coolant passes through the second heat exchange element, thereby forming a conditioned air flow from the primary air flow.

Under second atmospheric conditions, the first and third heat exchange elements may not be able to cool the primary air stream to the desired set point temperature.

The method further provides, at a second atmospheric condition:

-extracting thermal energy from the first coolant by evaporation;

-supplying a first coolant to the first indirect heat exchange element; and

-forcing the main air flow through the first heat exchange element, whereby thermal energy is transferred from the air flow to the first coolant when the air flow passes through the first heat exchange element.

The method also provides, at a second atmospheric condition:

-distributing a third coolant over the third direct heat exchange element;

-forcing the main air flow through the third heat exchange element, thereby extracting thermal energy from the air flow and absorbing moisture from the third coolant to the air flow when the air flow is in contact with the third coolant.

Transfer of thermal energy from the second coolant to the hot sink is also provided. According to an exemplary embodiment of the invention, the heat transfer device is in the form of a heat pump and the heat sink is the atmosphere.

The first atmospheric condition is set to favor evaporative cooling over the second atmospheric condition. More specifically, air at a first atmospheric condition has a lower relative humidity than air at a second atmospheric condition. Therefore, the wet bulb pressure drop is greater at the first atmospheric condition than at the second atmospheric condition, and the wet bulb pressure drop is the largest contributor to system efficiency.

The above and other features of the present invention will be described in more detail below.

Drawings

An embodiment of the invention is described hereinafter, by way of non-limiting example only, and with reference to the accompanying drawings, in which:

FIG. 1 is a schematic cut-away perspective front view of a hybrid air cooling system according to the present invention;

FIG. 2 is a schematic cut-away perspective rear view of a main cooling unit forming part of the system of FIG. 1;

FIG. 3 is a schematic rear view of the main cooling unit in use; and

fig. 4 is a schematic front view of the main cooling unit in use.

Detailed Description

Referring to the drawings, wherein like numerals indicate like features, a hybrid air cooling system according to the present invention is generally indicated by reference numeral 10 in FIG. 1.

The system 10 includes a primary inlet 12 (see fig. 4) for receiving a primary air flow 14, a primary outlet 16 for supplying a conditioned air flow 18 to a conditioned space (not shown), and a primary air flow passage 20 extending between the primary inlet 12 and the primary outlet 16.

The system 10 also includes a primary heat exchange device 22 disposed in the primary air flow path 20. Main heat exchange means 22 is adapted to allow main air stream 14 to operatively pass through main heat exchange means 22 to extract heat energy from main air stream 14 as main air stream 14 passes therethrough to form conditioned air stream 18. The main heat exchange means 22 comprises a first indirect heat exchange element 24 which uses a first coolant 26 to extract thermal energy from the main air stream 14, a second indirect heat exchange element 28 which uses a second coolant 30 to extract thermal energy from the main air stream 14, and a third direct heat exchange element 32 which uses a third coolant 34 to extract thermal energy from the main air stream 14. During the cooling phase, the primary air stream 14 does not absorb any additional moisture as the primary air stream 14 passes through the first indirect heat exchange element 24 and the second indirect heat exchange element 28, and during the cooling phase, the primary air stream 14 absorbs some additional moisture as the primary air stream 14 passes through the third direct heat exchange element 32. This is because the primary air stream 14 is not in contact with the first coolant 26 and the second coolant 30 when the primary air stream 14 is operatively passed through the first indirect heat exchange element 24 and the second indirect heat exchange element 28, but the primary air stream 14 is indeed in contact with the third coolant 34 when the primary air stream 14 is operatively passed through the third heat exchange element 32.

In accordance with the exemplary embodiment of the present invention as shown, the first, second and third heat exchange elements 24, 28, 32 are positioned in series such that the primary air flow 14 operatively passes through each of these heat exchange elements 24, 28, 32 as the primary air flow 14 moves from the primary inlet 12 to the primary outlet 16. A primary air blower 36 located in the primary air flow passage 20 is operable to induce the primary air flow 14.

The system 10 also includes an evaporative cooling unit 38 that extracts thermal energy from the first coolant 26 by evaporation before the first coolant 26 is operatively provided to the first indirect heat exchange element 24. The system 10 includes a thermal energy reservoir 40 operable to absorb thermal energy from the second coolant 30 before the second coolant 30 is operably supplied to the second indirect heat exchange element 28.

The system 10 also includes a primary coolant distribution device 42 for distributing the tertiary coolant 34 over the third direct heat exchange element 32, thereby operable to extract thermal energy from the primary air stream 14 when the primary air stream 14 is in contact with the tertiary coolant 34, and moisture from the tertiary coolant 34 is operably absorbed into the primary air stream 14.

The primary inlet 12, the primary outlet 16, the primary air flow passage 20 and the primary heat exchange means 22 together form a primary cooling unit. Preferably, the main cooling unit is integrally connected to the evaporative cooling unit 38.

The system 10 is configured to operatively cool the primary air stream 14 at a first atmospheric condition by extracting thermal energy from the primary air stream 14 by means of only the first and third heat exchange elements 24, 32, and to operatively cool the primary air stream 14 at a second atmospheric condition by extracting thermal energy from the primary air stream 14 by means of the second indirect heat exchange element 28 due to the first and third heat exchange elements 24, 32 being unable to cool the primary air stream 14 to the desired set point temperature. The first atmospheric condition is more favorable to evaporative cooling than the second atmospheric condition. Thus, the wet bulb pressure drop, which is the largest contributor to unit efficiency, is greater at first atmospheric conditions than at second atmospheric conditions that require the extraction of thermal energy through the first and third heat exchange elements 24, 32 and the second indirect heat exchange element 28. It is contemplated that second heat exchange element 28 may operate alone or in combination with first and third heat exchange elements 24, 32, depending on operational requirements.

Turning to fig. 2 and 3, the evaporative cooling unit 38 includes a secondary inlet 44 (in this exemplary embodiment, two opposing secondary inlets 44) for receiving a secondary air flow 46, a secondary outlet 48 for discharging an exhaust gas flow 50 from the cooling unit 38, and a secondary air flow channel 52 extending between the secondary inlet 44 and the secondary outlet 48. A secondary air blower 54 located in the secondary air flow path 52 is operable to introduce the secondary air flow 46.

The evaporative cooling unit 38 further includes a secondary direct heat exchange element 56, in this example embodiment two opposed heat exchange elements 56, each heat exchange element 56 being located adjacent one of the secondary inlets 44, disposed in the secondary air flow passage 52 and adapted to allow the secondary air flow 46 to operatively pass therethrough.

A secondary coolant distribution device 58 in the form of a secondary manifold is located above each of the elements 56 for distributing the first coolant to each of the secondary direct heat exchange elements 56. When the first coolant 26 is in contact with the secondary air stream 46, thermal energy is operatively extracted from the first coolant 26 by evaporative cooling, and moisture from the first coolant 26 is absorbed into the secondary air stream 46. Thermal energy needs to be applied to the first coolant 26 to change it from a liquid to a vapor, and when a phase change occurs, heat is lost from the first coolant 26, which results in cooling of the first coolant 26.

As shown, a secondary coolant reservoir 60 is located below each of the secondary heat exchange elements 56 for operatively receiving and accumulating the cooled first coolant 26 flowing from the secondary direct heat exchange elements 56. The first coolant 26 is typically operatively supplied from the secondary coolant reservoir 60 to the secondary coolant distribution device 58 through the first indirect heat exchange element 24 via at least one liquid circulation pump and associated piping (not shown).

The first indirect heat exchange element 24 comprises a length of tubing through which the first coolant 26 operatively flows and over which the primary air stream 14 passes, whereby thermal energy is transferred from the primary air stream 14 to the first coolant 26, thereby cooling the primary air stream 14. The first coolant 26 is operatively supplied to the first indirect heat exchange element 24 from the secondary coolant reservoir 60, wherein thermal energy is transferred from the primary air flow 14 to the first coolant 26, then from the first indirect heat exchange element 24 back to the secondary coolant distribution device 58, then back to the secondary direct heat exchange element 56 for cooling.

A heat transfer device 62 is provided for transferring thermal energy from the second coolant 30 to the hot sink. In this exemplary embodiment of the invention, the heat transfer device 62 is in the form of a heat pump and the heat sink is atmospheric air.

The thermal energy store 40 comprises an insulating housing 64 in which a plurality of thermal energy storage elements 66 are stacked, each element 66 having an outer shell formed of a flexible material and filled with a thermal energy storage medium (not shown) in the form of a phase change medium, such as water. The reservoir 40 further includes a stored coolant distribution device 68 in the form of a storage manifold for distributing the second coolant 30 to the thermal energy storage elements 66 so that thermal energy is operatively allowed to transfer between the second coolant 30 and the thermal energy storage elements 66 as the second coolant 30 flows through the thermal energy storage elements 66.

The second indirect heat exchange element 28 comprises a length of tubing through which the second coolant 30 operatively flows and over which the primary air stream 14 passes, whereby thermal energy is transferred from the primary air stream 14 to the second coolant 30.

According to a first example operating state of the system 10, the second coolant 30 is operatively supplied to the second indirect heat exchange element 28 via a conduit 70 from, for example, a lower bottom region of the thermal energy store 40, due to the need to extract thermal energy from the primary air stream 14 by means of the second indirect heat exchange element 28 in order to cool the air stream 14 to the desired setpoint temperature. To accomplish the same, the valves 72A, 72C and 72E mounted on the conduit 70 need to be in an open configuration to allow the second coolant 30 to operatively pass through them, and the valves 72B and 72D also mounted on the conduit 70 need to be in a closed configuration to prevent the second coolant 30 from operatively passing through them.

At the second indirect heat exchange element 28, thermal energy is transferred from the primary air flow 14 to the second coolant 30, the second coolant 30 then being returned from the second indirect heat exchange element 28 to the thermal energy reservoir 40 through the stored coolant distribution device 68, where the thermal energy is transferred from the second coolant 30 to the reservoir 40 in the stored coolant distribution device 68. More specifically, when the second coolant 30 and the thermal energy storage element 66 are in contact with each other, thermal energy is transferred from the second coolant 30 to the thermal energy storage element 66.

Furthermore, according to a second example operating state of the system 10, since there is no need to extract thermal energy from the primary air stream 14 by means of the second indirect heat exchange element 28 to cool the air stream 14 to the desired set point temperature, and the thermal energy storage element 66 needs to be cooled (charged), the second coolant 30 is operatively supplied from (the lower bottom region of) the thermal energy store 40 to the heat transfer device 62 through the conduit 70. To accomplish the same, valves 72A and 72D need to be in a closed configuration to prevent second coolant 30 from operatively passing through them and thus through second indirect heat exchange element 28, and valves 72B, 72C, and 72E need to be in an open configuration to allow second coolant 30 to operatively pass through them.

At the heat exchange device 62, thermal energy is expelled from the second coolant 30 to the heat sink, and the second coolant 30 is then returned from the heat transfer device 62 to the thermal energy storage 40 via the storage coolant distribution device 68, where the thermal energy is transferred from the storage 40 to the second coolant 30 in the storage coolant distribution device 68. More specifically, when the thermal energy storage element 66 and the second coolant 30 are in contact with each other, thermal energy is transferred from the thermal energy storage element 66 to the second coolant 30.

Furthermore, according to a third example operating state of the system 10, since the temperature of the ambient air is below the desired temperature of the conditioned space, it is necessary to add thermal energy to the primary air flow 14 by means of the second indirect heat exchange element 28 to heat the air flow 14 to the desired set point temperature. The second coolant 30 is operatively supplied to the heat transfer device 62 from the second indirect heat exchange element 28 through a conduit 70. To accomplish the same, valves 72B, 72C, and 72E need to be in a closed configuration to prevent the second coolant 30 from operatively passing therethrough, and valves 72A and 72D need to be in an open configuration to allow the second coolant 30 to operatively pass therethrough.

At the heat exchange device 62, thermal energy is transferred to the second coolant 30, and the coolant 30 is then returned from the heat transfer device 62 to the second indirect heat exchange element 28, where the thermal energy is transferred from the second coolant 30 to the air stream 14.

A main coolant reservoir 74 is provided below the main heat exchange device 22 for operatively receiving and accumulating the third coolant 34 flowing from the third direct heat exchange element 32, as well as any condensate flowing down the first and second indirect heat exchange elements 24, 28. The third coolant 34 is typically operatively supplied from the main coolant reservoir 74 to the main coolant distribution device 42 by a liquid circulation pump and associated piping (not shown), the main coolant distribution device 42 being in the form of a main manifold located at an operatively upper end of the third direct heat exchange element 32.

The applicant believes that the present invention provides an effective solution for significantly reducing peak load power usage of a hybrid air cooling system, regardless of its operating state based on atmospheric conditions. More specifically, under (humid) atmospheric conditions not conducive to evaporative cooling, a cooling device in the form of a thermal energy store 40 may be used for cooling purposes, thus eliminating the need to use a refrigerant-based cooling device that consumes more power than an equivalent evaporative cooling device. Further, for example, thermal energy may be extracted from the thermal energy storage 40 when demand for electricity is low (e.g., at night) and in some cases when electricity prices are also low. Thus, when it may be desired to transfer thermal energy from the primary air flow 14 to the thermal energy storage 40 via the second coolant 30, the storage 40 is at a low operating temperature and is able to absorb thermal energy from the second coolant 30 for a long period of time.

It will be understood by those skilled in the art that the present invention is not limited to the precise details set forth herein and that many changes may be made without departing from the scope and spirit of the invention. For example, it is contemplated that the first and third heat exchange elements 24, 32 may be operatively used in conjunction with the second heat exchange element 28 to extract thermal energy from the primary air flow 14 at second atmospheric conditions. Similarly, under first atmospheric conditions, the second heat exchange element 28 may be operatively used in conjunction with the first and third heat exchange elements 24 to extract thermal energy from the primary air flow 14. Further, any of the heat exchange elements 24, 28, and 32 may be operable to be used alone, or in combination with any one or more of its residual heat exchange elements 24, 28, and 32 to extract thermal energy. Furthermore, in an exemplary embodiment of the invention, the system 10 may include a liquid inlet (not shown) for receiving the first coolant 26 from an external source (not shown), such as a ground water reservoir in addition to or in place of the evaporative cooling unit 38, which is then supplied to the first heat exchange element 24, after which the coolant 26 may be returned to the external source. It is also contemplated that in another embodiment of the present invention, any one or more of the evaporative cooling unit 38, the conduit 70, the heat transfer apparatus 62, and the thermal energy storage 40, and any one or more of their associated components, may be omitted, and the system 10 includes a liquid inlet (not shown) for receiving the first coolant 26 from an external source (not shown), such as a ground water storage in addition to or in place of the evaporative cooling unit 38, which is then supplied to the first heat exchange element 24, after which the coolant 26 may be returned to the external source.

The description is intended to provide the most useful and readily understood description of the principles and conceptual aspects of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for a fundamental understanding of the invention.