US20230366563A1

US20230366563A1 - Chilled beam with fans

Info

Publication number: US20230366563A1
Application number: US18/195,490
Authority: US
Inventors: Steve Lamica; Yi Li
Original assignee: Mestek Inc
Current assignee: Mestek Inc
Priority date: 2022-05-12
Filing date: 2023-05-10
Publication date: 2023-11-16
Also published as: CA3199355A1

Abstract

A heating and air conditioning unit includes a manifold having an induction aperture and a discharge slot, the induction aperture permitting passage of ambient air into the heating and air conditioning unit from a space outside of the manifold, and the discharge slot permitting passage of mixed air from the heating and air conditioning unit. An array of fans is mounted within the manifold in communication with the induction aperture, the array of fans selectively inducing a flow of the ambient air into the heating and air conditioning unit through the induction aperture. A heat exchanger is mounted within the manifold on an upstream side of the array of fans, the heat exchanger treating the flow of ambient air pulled through the heat exchanger by the array of fans.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application Serial No. 63/341,222, filed on May 12, 2022, which is herein incorporated by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates generally to heating, ventilation, and air conditioning (HVAC) systems and more particularly, to chilled beam HVAC units that incorporate fans to provide temperature management with as little primary airflow as possible.

BACKGROUND OF THE INVENTION

Chilled beams HVAC systems are either active systems that include an integrated air supply or passive systems that do not. Unsurprisingly, the integration of an air supply and the generated induction in active systems allows active chilled beam (ACB) systems to provide a greater cooling capacity than a passive chilled beam unit. Given their greater cooling capacity, ACBs are desirable for use in a variety of settings including both “ventilation-driven” and “cooling-driven” applications.
Ventilation-driven applications include spaces with high ventilation requirements and/or high latent load density relative to sensible loads such as classrooms, laboratories, patient rooms, etc. In ventilation-driven applications, the primary airflow provided to the ACB is determined by ventilation or latent requirements, rather than by sensible cooling. Active chilled beam units generally have excellent energy efficiency in such applications as there is significant primary airflow provided.
In contrast, cooling-driven applications include spaces with low ventilation requirements and low latent loads relative to sensible loads, such as, for example, office spaces. Known active chilled beams are not well suited for cooling-driven applications, however, as ACBs provide a cooling capacity that is proportional to the primary airflow the ACB receives. As cooling-driven settings typically require and include a relatively low amount of primary airflow, ACBs can only provide a limited amount of cooling in such settings. It is therefore challenging to design ACB systems to meet sensible cooling loads using the typical minimum air flow standards, i.e., the greater of 1) the minimum airflow to satisfy code ventilation requirements; or 2) the minimum to satisfy space latent loads.
Therefore, a need exists a chilled beam unit that can accommodate low primary airflow provided in, for example, cooling-driven applications such as office spaces.

SUMMARY OF THE INVENTION

With the forgoing concerns and needs in mind, it is the general object of the present invention to provide a chilled beam unit that can accommodate low primary airflow.
In an embodiment, a chilled beam unit includes a manifold having at least one induction aperture and at least one discharge slot, said induction aperture enabling a passage of air into the chilled beam unit from a space below the chilled beam unit and the discharge slot enabling a passage of air out of the chilled beam unit. The chilled beam unit also includes at least one fan mounted within said manifold about the induction aperture and configured to induce a flow of air from the space below the chilled beam unit into said chilled beam unit through the induction aperture. The chilled beam unit further including a heat exchanger mounted within the manifold on an upstream side of the array of fans and configured to accept a flow of air therethrough.
These and other objectives of the present invention, and their preferred embodiments, shall become clear by consideration of the specification, claims and drawings taken as a whole.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be better understood from reading the following description of non-limiting embodiments, with reference to the attached drawings, wherein below:

FIG. 1 illustrates an isometric, top view of a chilled beam unit, according to one embodiment of the present invention.

FIG. 2 illustrate an isometric, bottom view of the chilled beam unit, shown in FIG. 1 .

FIG. 3 illustrates an isometric, top view of the handline unit, shown in FIG. 1 , with a portion of the housing removed for clarity.

FIG. 4 illustrates a cross-section of the chilled beam unit of FIG. 1 .

FIG. 5 illustrates an alternate view of the cross-section of the chilled beam unit of FIG. 4 .

FIG. 6 illustrates the chilled beam unit of FIG. 1 with a portion of the chilled beam unit removed for clarity.

FIG. 7 illustrates a table of the cooling capacity of a chilled beam unit according to one embodiment of the present invention.

DETAILED DESCRIPTION

Reference will be made below in detail to exemplary embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference characters used throughout the drawings refer to the same or like parts, without duplicative description.
As used herein, the terms “substantially,” “generally,” and “about” indicate conditions within reasonably achievable manufacturing and assembly tolerances, relative to ideal desired conditions suitable for achieving the functional purpose of a component or assembly. As also used herein, the terms “upstream” and “downstream,” describe the position of the referenced elements with respect to a flow path of a fluid flowing between and/or near the referenced elements.
While embodiments disclosed herein are described with respect to use in cooling-driven applications, i.e., spaces with low ventilation requirements and low latent loads relative to sensible loads, such as office spaces, it is to be understood that embodiments of the invention may be applicable other settings and applications where there is little, reduced, or no primary airflow. In embodiments, inventive chilled beam units can be combined with traditional ACBs or other types of heating / cooling systems, e.g., baseboard and forced air.
FIG. 1 illustrates an isometric view of a chilled beam unit 10 according to an embodiment of the present invention. As shown, the unit 10 includes a housing 25 that has a substantially open interior cavity 26 (FIG. 3 ). FIG. 2 is an alternate isometric view of the chilled beam unit 10 of FIG. 1 depicting a manifold 20 that defines induction aperture 22 and discharge slots 24, and a housing 25 extending from the manifold 20. The induction aperture 22 enables air to pass into the chilled beam unit 10 from a space below the chilled beam unit 10 and the discharge slots 24 enable air to pass back out of the chilled beam unit 10.
As will be appreciated, embodiments of the inventive unit 10 and system are configured for ceiling installation. As such, the housing 25 may be recessed in a suspending ceiling with the discharge slots 24 and the induction aperture 22 facing substantially downward into the space. In this regard, the unit 10 may be sized and shaped to fit into a conventional suspended ceiling grid.
FIG. 3 illustrates the isometric view of the chilled beam unit 10 of FIG. 1 with a portion of the housing 25 removed for clarity. In particular, FIG. 3 illustrates an array of fans 30 mounted within the manifold 20 about the induction aperture 22. The array of fans 30 induce a flow of air from the space below the chilled beam unit 10 into the unit 10 through the induction aperture 22. A heat exchanger 40 is mounted within the manifold 20 on an upstream side of the array of fans 30. The heat exchanger 40 include one or more pipes through which a cooled or heated fluid, e.g., water, flows. As will be appreciated, the heat exchanger 40 accepts a flow of fluid (air) therethrough to transfer heat.
The array of fans 30 require minimal electricity for operation. In one embodiment, each fan runs on 12 volts of direct current electricity and consumes approximately 1.2 watts of power. In certain embodiments, an eight-foot-long chilled beam unit 10 has an array of twenty fans, resulting in about 24 watts of power consumption. As a result, the power consumption of the array of fans 30 is very low (similar to an LED light fixture). In the embodiment depicted in FIGS. 1-6 , the array of fans 30 are powered by a 24-volt AC/DC electrical connection, which is already provided to chilled beam units to power the control valve used to control water flow. This 24-volt wiring is connected to the array of fans 30 at a single point. As will be appreciated, while embodiments may include an array of twenty fans, other embodiments may have greater or fewer fans.
FIGS. 4 and 5 , in combination, illustrate cross-sectional views of an embodiment of the chilled beam unit 10. The depicted manifold 20 defines a single central induction aperture 22 and two discharge slots 24 each extending the length of the induction aperture 22. The array of fans 30 is mounted about the induction aperture 22 on a downstream side of the induction aperture 22. Air flows from the space below the chilled beam unit 10 through an induction grill and the heat exchanger 40 and through the induction aperture 22 into a hollow cavity 26 defined by the housing 25 of the chilled beam unit 10. The air mixed within the hollow cavity 26 and cooler air naturally separates from warmer air and falls out of the cavity 26 through the discharge slots 24.
In embodiments, a temperature sensor is mounted to the heat exchanger 40. In particular, the units 10 and system may utilize factory mounted sensors located on a tube of the coil of the heat exchanger 40. The sensor measures the temperature of the coil. In one embodiment, there are two temperature sensors, a first sensor that turns the fans on if the coil is cold, and a second sensor that turns the fans on if the coil is hot. As will be appreciated, the array of fans 30 are configured to induce the flow of air through the induction aperture 22 in response to the temperature measured by the sensor(s). In one embodiment, the array of fans 30 induce the flow of air through the induction aperture 22 if the sensor measures a temperature that is less than or greater than a threshold value. Each chilled beam unit 10 is configured as cooling only, heating only, or cooling and heating. The chilled beam units that are configured as cooling only and heating only switch on the array of fans 30 when the sensor measures a single temperature threshold value. Chilled beam units configured as cooling and heating switch on the array of fans 30 when the sensor measures one of two temperature threshold values. As will be appreciated, while described as located on a tube of the heat exchanger, the sensor(s) may be in a variety of locations within the chilled beam unit 10.
In embodiments, chilled beam units 10 are combined with conventional ACBs and the resulting overall system utilizes the control logic that is already programmed into the zone controller that controls the valve used to control water flow to the ACBs.
FIG. 7 illustrates the cooling capacity of one embodiment of a chilled beam unit 10. The chilled beam unit 10 is found to have the same performance as prior art chilled beam units. Typical operating conditions of 12 CFM/foot of primary air at 0.6 inches of plenum pressure and 725 BTUH/ ft were used in evaluating the performance for the purposes of testing a four-foot-long chilled beam unit 10 using a 75-degree room temperature set point and 56° F. water entering the heat exchanger 40. The air distribution pattern of the air exiting the air handing units 10 is similar to the air exiting prior art chilled beam units. An embodiment of the chilled beam unit 10 that was four feet long in a ceiling mode propelled air about ten feet across the ceiling before dropping. In a heating mode, an embodiment of the unit 10 had acceptable performance. The chilled beam unit 10, operating in a heating mode, can compliment low temperature baseboard heating in high heat-loss applications where the baseboard heater is insufficient and can help maximize winter energy efficiency.
The sound level or sound generated by chilled beam units is an integral factor in choosing the appropriate unit for the application. One embodiment of the chilled beam unit 10 generated a sound level of approximately NC32. A maximum sound level of NC40 is the typical target for open office HVAC systems. As a result, the sound level of the chilled beam unit 10 is suitable for most office spaces.
The chilled beam unit 10 disclosed herein is compatible with assemblies incorporating active chilled beam units that require connections to primary air sources. In some embodiments, units 10 are combined with conventional ACBs or other chilled beams systems. Here, the same water coils may be used for both. In particular, water coils / heat exchangers 40 may be piped in parallel with the heat exchangers of the other chilled beam units in the same zone and may be served by the same water control valves. In such systems, ACBs may represent a relatively small percentage of chilled beams in the overall system, e.g., 25%, depending on various design factors, e.g., additional sensible cooling requirements.
In one embodiment, the chilled beam unit 10 has the same (or lower) overall height of a prior art chilled beam unit (e.g., an “ACB40” chilled beam), the same mounting brackets, and the same appearance.
In another embodiment, an array of fans may be added or retrofitted to a conventional passive chilled beam unit or other chilled beam.
In certain embodiments, a controller (not shown) may be utilized for each unit 10. The controller could include one or more switches in communication with the sensors on the heat exchangers. For example, the controller may include a heating temperature switch and a cooling temperature switch. The switches in turn, may be in communication with the fans. The controller may also include a 24VAC to 12VDC converter. In embodiments, USB splitters may be employed to power the array of fans, though other solutions, e.g., a linear PCB, are certainly possible.
Although this invention has been shown and described with respect to the detailed embodiments thereof, it will be understood by those of skill in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed in the above detailed description, but that the invention will include all embodiments falling within the scope of this disclosure.

Claims

1. A chilled beam unit, comprising:

a manifold having at least one induction aperture and at least one discharge slot, said induction aperture enabling a passage of air into said chilled beam unit from a space below said chilled beam unit and said discharge slot enabling a passage of air out of said chilled beam unit;

at least one fan mounted within said manifold about said induction aperture and configured to induce a flow of air from said space below said chilled beam unit into said chilled beam unit through said induction aperture; and

a heat exchanger mounted within said manifold on an upstream side of said array of fans and configured to accept a flow of air therethrough.

2. The chilled beam unit of claim 1 wherein the at least one fan is an array of fans.

3. The chilled beam unit of claim 1 further comprising at least one temperature sensor mounted on the heat exchanger.

4. The chilled beam unit of claim 3 wherein the at least one temperature sensor is a first temperature sensor that turns on the at least one fan if the coil is cold, and a second temperature sensor that turns on the at least one fan if the coil is hot.

5. A heating and air conditioning unit, comprising:

a manifold having an induction aperture and a discharge slot, said induction aperture permitting passage of ambient air into said heating and air conditioning unit from a space outside of said manifold, and said discharge slot permitting passage of mixed air from said heating and air conditioning unit;

an array of fans mounted within said manifold in communication with said induction aperture, said array of fans selectively inducing a flow of said ambient air into said heating and air conditioning unit through said induction aperture; and

a heat exchanger mounted within said manifold on an upstream side of said array of fans, said heat exchanger thereby treating said flow of ambient air pulled therethrough via said array of fans.

6. The heating and air conditioning unit of claim 1, wherein:

said discharge slot extends substantially the entire length of said manifold.

7. The heating and air conditioning unit of claim 1, further comprising:

a temperature sensor mounted in communication with said heat exchanger.

8. The heating and air conditioning unit of claim 7, wherein:

said temperature sensor selectively turns on said fan when said temperature sensor determines said heat exchanger is below a predetermined temperature, and selectively turns off said fan when said temperature sensor determines said heat exchanger is above a predetermined temperature.

9. The heating and air conditioning unit of claim 1, wherein:

said heat exchanger includes fluid carrying piping.

10. The heating and air conditioning unit of claim 1, wherein:

each fan in said array of fans is powered by low voltage.

11. A method of conditioning ambient air within an enclosure, said method comprising the steps of:

arranging a manifold to be in fluid communication said enclosure, said manifold having an induction aperture and a discharge slot, said induction aperture permitting passage of said ambient air into said manifold from outside of said manifold, and said discharge slot permitting passage of mixed air from said manifold;

mounting a fan within said manifold in communication with said induction aperture, said fan selectively inducing a flow of said ambient air into manifold through said induction aperture; and

mounting a heat exchanger within said manifold on an upstream side of said fan, said heat exchanger thereby conditioning said flow of ambient air pulled therethrough via said fan.

12. The method of conditioning ambient air within an enclosure according to claim 11, said method further comprising the steps of:

powering said fan with a 12 volt supply of electricity.