Chilled Beam Air Conditioning System

Abstract

An improved chilled beam refrigeration and/or air conditioning systems uses a first chilled air flow to induce a second chilled air flow. Ambient air is drawn through first coils to produce a primary cooled air flow into an intake plenum on the suction side of a fan. The primary cooled air is drawn from the intake plenum, through the fan, and is exhausted into a discharge plenum at a positive pressure. Discharge nozzles along discharge face(s) of the discharge plenum direct the primary cooled air outward inducing a negative pressure in an area behind (or above) second coils. The negative pressure induces additional ambient air to be drawn through the second coils and cooled to provide additional cooled air. The additional cooled air mixes with the primary cooled air providing a larger refrigeration and/or air conditioning effect which would otherwise require additional motorized fans.

Description

BACKGROUND OF THE INVENTION

The present invention relates to refrigeration and/or air conditioning systems and in particular to chilled beam refrigeration and/or air conditioning systems.

Conventional refrigeration and/or air conditioning systems include a central forced air unit with a fan circulating air through coils of an evaporator. The evaporator receives a flow of fluid refrigerant which evaporates into a vapor refrigerant flow out of the evaporator and thereby drops in temperature. The air circulated through the evaporator is cooled and then circulated throughout a house or other structure to provide a flow of cooled air into various areas of the structure. Unfortunately, significant energy is required to circulate the cooled air throughout the structure.

Chilled beam refrigeration systems replace the circulation of the cooled air with circulation of cooled fluid. The cooled fluid is circulated through a radiator (or heat exchanger), generally at a high point in a room, making the radiator cold. Warm air rises and is cooled by the cold radiator, and falls back towards the floor. Less energy is required to circulate the fluid and required outside air so an energy savings results.

A passive chilled beam uses the heavier cool air to induce a draft through a coil thus providing cooling or refrigeration to an area. These passive types of coils can also be called “gravity coils” as they use the draft induced by cooling air to cool a space. These devices may or may not utilize drain pans to catch condensate in the event that the dewpoint of the coil is lower than that of the surrounding room.

An active chilled beam is a device that utilizes a duct in the center that is pressurized by an external source and has small holes or nozzles to point out and away from the unit. The pressurized air at 0.4 to 1.0 inches of water of positive static pressure induces additional air to flow through the coil. The amount of air induced as a result of the pressurized nozzles can vary from 1:1 ratio of pressurized air to induced air flow up to six or eight times of induced air versus the amount of supplied pressurized air.

Unfortunately, while energy savings result from circulating liquid state fluid instead of air, the air flow through the radiator is often less than the optimal air flow for cooling the room.

BRIEF SUMMARY OF THE INVENTION

The present invention addresses the above and other needs by providing an improved chilled beam refrigeration and/or air conditioning systems which uses a first chilled air flow to induce a second chilled air flow. Ambient air is drawn through first coils to produce a primary cooled air flow into an intake plenum on the suction side of a fan. The primary cooled air is drawn from the intake plenum, through the fan, and is exhausted into a discharge plenum at a positive pressure. Discharge nozzles along discharge face(s) of the discharge plenum direct the primary cooled air outward inducing a negative pressure in an area behind (or above) second coils. The negative pressure induces additional ambient air to be drawn through the second coils and cooled to provide additional cooled air. The additional cooled air mixes with the primary cooled air providing a larger refrigeration effect which would otherwise require additional motorized fans.

In accordance with one aspect of the invention, there is provided an improved chilled beam unit including the elements of an active chilled beam unit in that the improved chilled beam unit includes nozzles to induce airflow through secondary coil(s) while as the same time having a fan integrated into the improved chilled beam unit to supply pressurized air to the improved chilled beam unit so that the improved chilled beam unit is self contained.

In accordance with another aspect of the invention, there is provided an improved chilled beam unit which may include a drip pan to catch the condensate depending on operating conditions.

In accordance with yet another aspect of the invention, there is provided an improved chilled beam unit having one, two or three coils for primary and induced air paths.

In accordance with still another aspect of the invention, there is provided an improved chilled beam unit configurable to have either unidirectional (for sidewall) or bidirectional airflow (for center of room locations).

In accordance with another aspect of the invention, there is provided an improved chilled beam unit having controls to modulate the fan speed to deliver specific air induction characteristics.

In accordance with still another aspect of the invention, there is provided an improved chilled beam unit having controls to modulate the coil temperature in relation to the dew point level of the room to prevent condensation.

In accordance with still another aspect of the invention, there is provided an improved chilled beam unit utilizing either direct expansion or secondary heat transfer fluids.

In accordance with another aspect of the invention, there is provided an improved chilled beam unit having one or more fans to draw the primary air flow to create the desired induced air flow.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

The above and other aspects, features and advantages of the present invention will be more apparent from the following more particular description thereof, presented in conjunction with the following drawings wherein:

FIG. 1 is a prior art refrigeration and/or air conditioning system.

FIG. 2 shows a prior art distribution of cooled air through ducting to outlets in various rooms.

FIG. 3 shows a prior art chilled beam system distributing cooled liquid state fluid to chilled beam units in the various rooms.

FIG. 4 shows a prior art chilled beam unit.

FIG. 5A shows a side view of an improved chilled beam unit according to the present invention and drip tray.

FIG. 5B shows an end view of the improved chilled beam unit according to the present invention and drip tray.

FIG. 5C shows a bottom view of the improved chilled beam unit according to the present invention and drip tray.

FIG. 6A shows a side view of the improved chilled beam unit according to the present invention with the drip tray removed.

FIG. 6B shows an end view of the improved chilled beam unit according to the present invention with the drip tray removed.

FIG. 6C shows a bottom view of the improved chilled beam unit according to the present invention with the drip tray removed.

FIG. 7 shows a cross-sectional view of the improved chilled beam unit according to the present invention taken along line 7-7 of FIG. 6A.

FIG. 8 shows a primary air flow through the improved chilled beam unit according to the present invention.

FIG. 9 shows an induced air flow through the improved chilled beam unit according to the present invention.

Corresponding reference characters indicate corresponding components throughout the several views of the drawings.

DETAILED DESCRIPTION OF THE INVENTION

The following description is of the best mode presently contemplated for carrying out the invention. This description is not to be taken in a limiting sense, but is made merely for the purpose of describing one or more preferred embodiments of the invention. The scope of the invention should be determined with reference to the claims.

A diagram showing a known refrigeration and/or air conditioning system 10 is shown in FIG. 1. Typically, the compressor 12 compresses refrigerant into a high-pressure vapor refrigerant flow 14 through a pressure line 15 into a condenser 16. An outdoor fan 17 creates an air flow 19a across the condenser 16 which cools the high-pressure vapor refrigerant flow 14 by removing heat and condenses the high-pressure vapor flow 14 to a liquid state fluid refrigerant flow 18. The heat added to the air flow 19a produces a heated air flow 19b. The liquid state fluid refrigerant flow 18 flows along a refrigerant pipeline, through a metering device 26, and into an evaporator coil 20.

The metering device 26 controls the rate at which refrigerant enters the evaporator coil 20 and also creates a pressure drop. The pressure drop allows the refrigerant to expand from a small diameter tube to a larger diameter. The liquid state fluid refrigerant flow 18 evaporates back to a vapor refrigerant flow 22 in the evaporator 20 experiencing a temperature drop. An evaporator fan 28 blows air 24a across the cold evaporator coil 20 and heat transfers from the air flow 24a into the cold vapor refrigerant flow 22 to provide a cooled air flow 24b into a living area. The vapor refrigerant flow 22 then returns to the compressor 12 through a suction line 23 to start the cycle over again.

A prior art Heating, Ventilation, and Air Conditioning (HVAC) system distributes cooled or heated air from a central unit 32 through ducting 34 to outlets 36a, 36b, and 36c in various rooms 30a, 30b, and 30c is shown in FIG. 2. The ducting 34 must be large to have sufficient capacity with low restriction to air flow. The size of the ducting 34 may limit installation of such systems to locations where substantial space is available, and the large surface area of the ducting provides opportunities for leaks and damage.

A prior art chilled beam system distributing a cooled fluid from a central unit 32 or an exterior unit 38 through lines 42 to chilled beam units 40a , 40b, and 40c in the various rooms 30a, 30b, and 30c and return the fluid through lines 44 is shown in FIG. 3 and a prior art chilled beam unit 40 is shown in FIG. 4. The lines 42 and 44 are much smaller than the ducting 34 and allow installation in many more locations. The chilled beam unit 40 may be active or passive and conducts heat or cold from the lines 42 to the ambient air 46 in the room to provide heated or cooled air 48. Because of the much greater volumetric heat capacity of liquid state fluids, the chilled beam unit 40 provides fairly efficient operation.

The fluid may be a refrigerant which is in a liquid state in the lines 42, evaporate to a gas state in coils in the chilled beam units, and returns to the exterior unit 38 in the gas state, or a secondary fluid such as water or a water-glycol mixture, which remains in liquid state at all times.

A side view of an improved chilled beam unit 50 according to the present invention and drip tray 54 is shown in FIG. 5A, an end view of the chilled beam unit 50 and drip tray 54 is shown in FIG. 5B, and a bottom view of the chilled beam unit 50 and drip tray 54 is shown in FIG. 5C. The drip tray 54 may include baffles 52 along its sides and bottom to direct an ambient air flow drawn into the improved chilled beam unit 50 to prevent or reduce mixing of the air flows, or may simply include passages with raised lips to trap condensation in the drip trays while allowing the flow of ambient air. The drip pan 54 may or may not be present depending on the need to catch condensation on the coils.

A side view of the chilled beam unit 50 with the drip tray 54 removed is shown in FIG. 6A, an end view of the chilled beam unit 50 with the drip tray removed is shown in FIG. 6B, a bottom view of the chilled beam unit 50 with the drip tray removed is shown in FIG. 6C, and a cross-sectional view of the chilled beam unit 50 taken along line 7-7 of FIG. 6A is shown in FIG. 7. The chilled beam unit 50 includes primary coils 66a on a center bottom surface. Ambient room 46a is drawn through the primary coils 66a into an intake plenum 70 by a fan (or blower) 62. The ambient air 46a is either heated or cooled as it passes through the primary coils 66a providing a primary air flow 60 into the intake plenum 70. The primary air flow 60 is then drawn from the intake plenum 70 and blown into a discharge plenum 72 by the fan 62. The primary air flow 60 then escapes the discharge plenum 72 through discharge ports 64.

The flow of discharged air 58 creates low pressure above the secondary coils 66b drawing additional ambient room air 46b through the secondary coils 66b to create an induced air flow 56. The flow of discharged air 58 combines with the induced flow 56 to provide a greater air flow than the primary air flow 60 without requiring an additional fan, thus improving efficiency of the chilled beam unit 50. A two sided chilled beam unit is shown in FIGS. 6A-7 which is suitable for positioning in the center of a room or away from walls. A single sided chilled beam unit 50 having one secondary coil 66b and only one set of discharge ports 64 on one side of the chilled beam unit 50 is suitable for mounting near or against a wall. The chilled beam unit 50 may further include one, two, or three coils in the primary flow path and in the induced air path(s), and the flow of the fluid through the coils may be controlled as needed to control coil temperature in relation to due point to prevent condensation. The chilled beam unit 50 may utilize either refrigerants or chilled water/glycol mixtures as a heat transfer fluid.

The primary coils 66a are housed in a primary coil housing 67a and the secondary coils 66b are housed in secondary coil housings 67b. The primary coil housing 67a is generally horizontal and the secondary coil housings 67b are tilted up from the horizontal at angle A. The angle A is preferably between zero degrees and 60 degrees and preferably approximately 45 degrees.

The primary air flow 60 only through the chilled beam unit 50 is shown in FIG. 8. The ambient air 46a is drawn into the chilled beam unit 50 through the primary coils 66a by low pressure in the intake plenum 70. The primary air flow then passes through the fan 62 and into the discharge plenum 72, and out through the discharge ports 62 creating the discharge flow 58.

The induced air flow through the chilled beam unit 60 is shown in FIG. 9. The discharge flow 58 creates low pressure above the secondary coils 68b. The low pressure draws the ambient air 46b through the secondary coils 66b to mix with the discharge flow 58 providing a greater flow of heated or cooled air.

The fan 62 may be single speed or multi-speed to provide a specific primary air flow. The chilled beam unit 50 may also include more than one fan as needed.

While the invention herein disclosed has been described by means of specific embodiments and applications thereof, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope of the invention set forth in the claims.

Claims

1. A Heating, Ventilation, and Air Conditioning (HVAC) system comprising:

a source of cooled fluid;

first lines carrying the cooled fluid from the source of cooled fluid;

second lines returning the fluid to the source of cooled fluid;

a chilled beam comprising: a housing having openings to receive a first flow of ambient air from an area the chilled beam resides in; coils residing in the housing and receiving the cooled fluid from the first lines and releasing the cooled fluid to the second lines; a fan urging the first flow of ambient air to pass through the coils to create a primary cooled air flow; discharge ports allowing the escape of the primary cooled air flow from the housing to create a flow of discharged air; a low pressure area next to the housing created by the flow of discharged air; and a second flow of ambient air into the housing, the low pressure area drawing the second flow of ambient air through the coils to create an induced flow from the housing; and

the induced flow combining with the flow of discharged air to cool the room.

2. The HVAC system of claim 1, wherein:

the coils include first coils on a floor of the housing; and

the first flow of ambient air passes through first coils.

3. The HVAC system of claim 2, wherein:

the coils include second coils on the side of the first coils; and

the second flow of ambient air passes through the second coils.

4. The HVAC system of claim 3, wherein:

the second coils comprise coils residing on right and left sides of the first coils; and

the second flow of ambient air passes through the second coils.

5. The HVAC system of claim 4, wherein the second coils residing at a tilt of between zero and 60 degrees.

6. The HVAC system of claim 5, wherein the second coils residing at a tilt of approximately 45 degrees.

7. The HVAC system of claim 5, wherein;

an inside edge of the second coils resides along edges of the first coils; and

the second coils tilt up and away from the first coils.

8. The HVAC system of claim 1, wherein:

the first coils reside under an intake plenum running the length of the housing;

a discharge plenum resides above the intake plenum and runs the length of the housing;

the discharge ports reside along at least one side of the discharge plenum; and

the fan resides between the intake plenum and the discharge plenum and draws air from the intake plenum and pushes the air into the discharge plenum.

9. The HVAC system of claim 8, wherein the discharge ports reside along opposite sides of the discharge plenum.

10. The HVAC system of claim 1, wherein the fluid is chilled water.

11. The HVAC system of claim 1, wherein the fluid is a chilled water and glycol mixture.

12. The HVAC system of claim 1, wherein the cooled fluid from the source of cooled fluid is a liquid state fluid refrigerant and the fluid returned to the source of cooled fluid is a gas state fluid refrigerant.

13. A Heating, Ventilation, and Air Conditioning (HVAC) system comprising:

a source of cooled fluid;

first lines carrying the cooled fluid from the source of cooled fluid;

second lines returning the fluid to the source of cooled fluid;

a chilled beam comprising: an intake plenum having openings along the bottom to receive a first flow of ambient air from an area the chilled beam resides in; first coils residing in the bottom of the intake plenum and receiving the cooled fluid from the first lines and releasing the cooled fluid to the second lines; a discharge plenum residing above the intake plenum and running the length of the intake plenum; discharge ports reside along at least one side of the discharge plenum; a fan drawing a first flow of ambient air into the intake plenum and through the first coils, pushing the first flow into the discharge plenum and out through the discharge ports to create a flow of discharged air; a low pressure area next to the discharge plenum created by the flow of discharged air; second coils on at least one side of the intake plenum below the low pressure area; and a second flow of ambient air through the second coils, the low pressure area drawing the second flow of ambient air through the second coils to create an induced flow; and

the induced flow combining with the flow of discharged air to cool the room.

14. A Heating, Ventilation, and Air Conditioning (HVAC) system comprising:

a source of cooled fluid;

first lines carrying the cooled fluid from the source of cooled fluid;

second lines returning the fluid to the source of cooled fluid;

a chilled beam comprising: an intake plenum having openings along the bottom to receive a first flow of ambient air from an area the chilled beam resides in; first coils residing in the bottom of the intake plenum and receiving the cooled fluid from the first lines and releasing the cooled fluid to the second lines; a discharge plenum residing above the intake plenum and running the length of the intake plenum; discharge ports reside along opposite sides of the discharge plenum; a fan drawing a first flow of ambient air into the intake plenum and through the first coils, pushing the first flow into the discharge plenum and out through the discharge ports to create flows of discharged air on opposite sides of the discharge plenum; low pressure areas next to the discharge plenum created by the flows of discharged air; second coils on opposite sides of the intake plenum below the low pressure areas; and second flows of ambient air through the second coils, the low pressure areas drawing the second flows of ambient air through the second coils to create induced flows; and

the induced flows combining with the flow of discharged air to cool the room.