A chilled beam, more particularly, an active chilled beam, is a combined discharge register and heat exchanger that is provided in the ceiling of a conditioned space. The discharge register portion receives primary air that is conditioned to satisfy the latent load of the conditioned space, the ventilation requirements of the conditioned space, and some of the sensible load of the conditioned space. The sensible load is further satisfied in an active chilled beam by cooling primary and some secondary conditioned space air using the heat exchanger portion. The primary air is ejected through nozzles to create the secondary flow by induction thereof. Water is pumped through the heat exchanger portion at a temperature that is above the dew point to prevent the heat exchanger portion causing condensation.
Active chilled beams provide benefits in areas with substantial sensible cooling and heating requirements and relatively mild ventilation requirements. This is because they can save on the primary air requirements associated with traditional VAV systems. Active chilled beams also are associated with low noise levels.
In addition, due to the very low noise levels of active chilled beams buildings that have special noise levels requirements are good candidates. Finally zones where there is high concern about indoor environment quality are ideal candidates as the conditioned spaces are provided with proper ventilation air and humidity control at all times and under all load conditions.
Generally, active chilled beams in a zone are supplied by a respective air handling unit. The air handling units can provide temperature-neutral latent load reduction by, for example, a desiccant wheel. The water temperature can be controlled by a control valve regulating flow through the heat exchanger portion from a water supply to a return. Water temperature can also be controlled by varying the rate of flow on either side of a heat exchanger that removes heat from the water.
The Summary describes and identifies features of some embodiments. It is presented as a convenient summary of some embodiments, but not all. Further the Summary does not identify critical or essential features of the embodiments, inventions, or claims.
According to an embodiment of the disclosed subject matter, a method of satisfying the load of a conditioned space includes conveying primary air from a central air handling unit to the primary air inlet of a chilled beam. The method further includes conveying conditioned return air to the primary air inlet of the chilled beam. In a variation, the conveying conditioned return air includes cooling return air from the conditioned space and mixing the result with the primary air from the central air handling unit to produce a combined primary air stream, which is provided to the primary air inlet of the chilled beam. In another variation, the conveying conditioned return air includes cooling return air from the conditioned space and mixing the result in a terminal unit with the primary air from the central air handling unit to produce a combined primary air stream, which is provided to the primary air inlet of the chilled beam. In yet another variation, the conveying primary air from a central air handling unit includes conveying primary air at a quality and rate that is sufficient to satisfy a ventilation load of the conditioned space but insufficient to supply a design thermal load requirement.
According to further embodiments, the disclosed subject matter includes a chilled beam system for a conditioned space. The system includes a handling unit configured to convey primary air from a central air handling unit to the primary air inlet of a chilled beam. The terminal unit configured to convey conditioned return air to the primary air inlet of the chilled beam. The conditioned return air may be cooled by the terminal unit and the result is mixed the terminal unit with the primary air from the central air handling unit to produce a combined primary air stream, which the terminal unit provides to the primary air inlet of the chilled beam. The terminal unit may be configured to mix the result in the terminal unit with the primary air from the central air handling unit to produce a combined primary air stream, and provide it to the primary air inlet of the chilled beam. The primary air from the central air handling unit may include a mechanism for conveying primary air at a quality and rate that is sufficient to satisfy a ventilation load of the conditioned space but insufficient to supply a design thermal load requirement. The terminal unit may include a condensing cooling coil configured to reduce the moisture content of the return air. The terminal unit includes a desiccant component configured to reduce the moisture content of the return air.
According to embodiments, the disclosed subject matter includes a method of satisfying the load of a conditioned space. The method includes creating a flow of primary air from a central air handling unit. The air handling unit provides fresh air from outside a building plus recirculated air in selectable ratios for form the primary air that is conveyed. The method further includes conveying the primary air from the central air handling unit to the inlet of chilled beams and creating a flow of conditioned recirculated air from terminal units. Each of the terminal units is connected to receive return air from a conditioned space served by a subset of the chilled beams and change an enthalpy of the return air to create the conditioned recirculated air. The primary air is received by the chilled beams after being combined with recirculated air flow created by the terminal units, the primary and recirculated air being combined within the terminal unit or by mixing output flows of the terminal units and the central air handling unit.
The conveying conditioned return air may include cooling return air from the conditioned space within the terminal unit and mixing the result with the primary air from the central air handling unit to produce a combined primary air stream, which is provided to the primary air inlet of the chilled beam. The changing of the enthalpy in the terminal units may include removing moisture from the return air.
According to embodiments, the disclosed subject matter includes a method of satisfying the load of a conditioned space. The method includes providing a terminal unit with a heat exchanger. The terminal unit is connected to a conditioned space to receive return air therefrom. The terminal unit is configured to condition the return air using the heat exchanger and combine conditioned return air with a primary air stream, which includes fresh air. The method further includes generating a heating mode signal and configuring one of the terminal unit and a chilled beam in response to the heating mode signal. The configuring includes changing an aspect ratio of a discharge into the occupied space or switching the flow into the occupied space from a first aspect ratio discharge to a second aspect ratio discharge, wherein the first and second aspect ratios differ in magnitude.
The method may include configuring the one of the terminal unit and a chilled beam in response to a cooling mode signal, the configuring including changing an aspect ratio of a discharge into the occupied space or switching the flow into the occupied space from the second aspect ratio discharge to the first aspect ratio discharge, wherein the first and second aspect ratios differ in magnitude.
According to embodiments, the disclosed subject matter includes apparatus for conditioning the air of an occupied space. The apparatus includes a terminal unit with a heat exchanger. The terminal unit is connected to a conditioned space to receive return air therefrom. The terminal unit is configured to condition the return air using the heat exchanger and combine conditioned return air with a primary air stream, which includes fresh air. The apparatus further includes a chilled beam and a controller configured to generate a heating mode signal. The controller is connected to control at least one actuator adapted to reconfigure one of the terminal unit, a chilled beam, or a further device in response to the heating mode signal. The reconfiguring includes changing an aspect ratio of a discharge into the occupied space or switching the flow into the occupied space from a first aspect ratio discharge to a second aspect ratio discharge, wherein the first and second aspect ratios differ in magnitude.
The terminal unit may include a damper configured to vary a mix of return air from the occupied space and air from the primary air stream. The terminal unit may include a powered air mover such as a fan or blower. Each terminal unit may be connected to multiple chilled beams and multiple terminal units may be connected to an air handler providing primary air.
The description set forth below in connection with the appended drawings is intended as a description of various embodiments of the invention and is not intended to represent the only embodiments in which the invention may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention may be practiced without these specific details. In some instances, well known structures and components are shown in block diagram form in order to avoid obscuring the concepts of the invention. In particular, exemplary embodiments are provided below that specifically describe camera-ready or printed documents. Such specifics are for illustrative purposes only and one of ordinary skill will recognize that documents of various, different formats may be used without departing from the scope of the present invention.
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Each chilled beam 101 receives final primary air 130 from a terminal unit 122 which conditions a return air stream 132 extracted from the conditioned space(s) 110. The return air stream may be provided from one or more return air registers serving (each of) the conditioned space(s) 110. The return air stream may also be provided from a selectable subset of multiple return air registers, one or more located near the ceiling for the cooling mode and one or more located low near the floor for heating mode. In embodiments, the heating or cooling return air registers may be selected based on whether heating or cooling is being supplied to the conditioned space employing any suitable control interconnect. The selection may be provided by a mode-switched damper, for example.
The terminal unit 122 conditions the return air 132 from the conditioned space and mixes the conditioned return air with initial primary air 133 from an air handling unit 120. The mixture forms the flow of final primary air 130. A fraction 174 (between 0 and 100 percent) of the return air may also be conveyed back to the air handling unit 120. A variable mixing box 182 may be provided to control the fraction of air returned to the terminal unit 122 and the air handling unit 120. The latter feature of a mixing box and return air channel to the air handling unit may be provided in any of the embodiments disclosed. A controller 193 may be provided to control the system and components as described below for any of the embodiments. The controller may generate heating mode signals, cooling mode signals in a conventional fashion. Also, or alternatively, the controller may generate commands or signals to cause the terminal units and/or chilled beams of the embodiments to configure for a cooling mode or a heating mode. The controller 193 may be connected to control one or more actuators 149 for configuring chilled beams and/or terminal unit dampers as described elsewhere in the present disclosure.
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With a higher volume rate including return air directly provided to the terminal unit as well as primary air from the air handling unit, the design beam volume rate may be met whilst still providing additional volume for effective use of the mixing register 421. In an alternative embodiment, a simple damper is used in the mixing register output and at least some air is always permitted to go to the beam output 137. The fan may be a variable rate fan and may be turned off under selected conditions, for example, proportionally in response to higher load, during heating (when the mixing register is used in combination with the beams). Note in some embodiments, the beams may be bypassed in heating mode and a mixing register used alone.
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In any of the embodiments, a damper 419 may provide for selection of the ratio of primary supply 133 from the air handling unit 120 and the return air 132 from the conditioned space. A fan 411 may be provided as discussed above and shown here. In low profile embodiments of terminal units, for example as discussed later for use with configurations that can fit over a hung ceiling, suitable fan designs such as tangential fans may be employed.
In embodiments of any of the systems described herein, return air passes through a mixing valve configured to exhaust a selectable amount of the return air and replace that amount with fresh air from a fresh air source. The resulting partial stream may be fed to the supply terminal unit.
In embodiments, the terminal unit 128 is configured to permit primary supply air to be tempered by a heat exchanger in addition to the tempering of the return air stream.
In embodiments of the systems described herein, return air passes through a mixing valve configured to exhaust a selectable amount of the return air. The resulting diminished stream is fed to the supply terminal unit. In a further embodiment, the terminal unit has mixes a selectable quantity of fresh air with the conditioned return air.
In any of the embodiments described, various control methods will be recognized as suitable for regulating the rate of heating or cooling required.
In any of the embodiments described, the terminal unit may include a regenerating desiccant to handle at least part of the latent load of the space.
In embodiments of the systems described herein, a terminal unit is retrofitted to an existing chilled beam system which is otherwise configured to provide only cooling. In such a retrofit, the terminal unit adds heating capability to the system.
In any of the embodiments described, a terminal unit is provided as a retrofit to provide an increased heating and/or cooling capacity to an existing chilled beam system.
In a method of providing a chilled beam system, a cooling load is satisfied by designing providing a capacity of a chilled beam air handling unit is based on ventilation requirements which may be ineffective for handling the total cooling load. In the method, the supplemental cooling effect is provided by a terminal unit as in any of the embodiments. In such system, the capacity of the terminal unit is sufficient to satisfy the total cooling load, reduced by the cooling effect provided by the air handling unit. In embodiments, systems are configured with components of the specified relative capacities.
In one or more system embodiments of a chilled beam system, a cooling load is satisfied by designing providing a capacity of a chilled beam air handling unit is based on ventilation requirements which may be ineffective for handling the total cooling load. In the systems, the supplemental cooling effect is provided by a terminal unit as in any of the embodiments.
In control embodiments, the heat exchanger and/or desiccant component of the terminal units are shut off when the capacity of the air handling unit is sufficient. In such embodiments, return air may be selectably made to bypass the heat exchanger or desiccant component to reduce pressure losses. In embodiments, the heat exchanger of terminal units 128 or 122 may be replaced with, or combined with, a desiccant enthalpy control device such as a desiccant wheel.
In one or more control embodiments, at times when ventilation load is low such as night-time, the terminal units provide latent and/or sensible load management and the air handling unit is shut down or operated intermittently.
One or more control devices (indicated as “XTL” in the figures) may be provided to control the terminal units, the air handling units or both. In any of the embodiments, the number of air handling units is independent of the number of terminal units.
In any of the embodiments, instead of a desiccant, a condensing heat exchanger may be provided. In any of the terminal unit embodiments, the heat exchanger 406 may be one or more heat exchangers at least one of which may include a condensing coil.
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In embodiments, the terminal units provide additional capacity without the need to provide additional air through the primary ventilation channels; e.g.,
As described above, terminal units may be connected to a main supply air duct that supplies air to one or more chilled beams and is provided from an air handling unit. As indicated, all or part of the air provided to the chilled beams (final primary air) may come from the main supply air duct (initial primary air). The final primary air can be a result of a series or parallel connection between the air handling unit and the terminal unit as described. The terminal unit may recycle room air and provide heating or cooling depending on the mode. Terminal units may provide only one or the other or both. Heating or cooling effect provided by the terminal units may be provided from a heat transfer fluid provided from a boiler or chiller or from an internal unit such as a vapor compression device (e.g. reversible heat pump) or a hydronic device such as an instant on-demand water heater or chiller.
The terminal unit may recycle air from the conditioned space of the chilled beams served by it. Also, as indicated, the return air may be partly (or fully) returned to the air handling unit. In embodiments, the terminal units recycle air through the heat exchanger to provide additional capacity. In this way chilled beams that provide only cooling may be provided with heating capability using heat from the terminal unit. This capability may be added as a retrofit product for an existing chilled beam system that lack heating capability, for example.
Any of the embodiments may be provided with a controller which activates the additional heating or cooling provided by the terminal unit in the event of a load that is greater than the capacity of the chilled beam system. Also, any of the embodiments may be provided with a controller which activates the additional heating or cooling provided by the terminal unit in the event of a detected need or commanded requirement of fast ramp to target conditions. In other words, in the latter case, the additional capacity is used to overcome thermal inertia thereby allowing, lower non-occupancy intervals such as during weekends at an office building or school building. Detection of a condition requiring the additional capacity provided by the terminal unit may be, for example, a current temperature lower than a threshold or a comfort. An open loop program for saving energy may employ regulate temperature using the auxiliary capacity of the terminal unit to maintain a target temperature or enthalpy profile over a period of predicted occupancy/non-occupancy cycle. Thus, the controller may receive the profile as a command or may store standard profiles which are selected via a user interface.
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In any of the embodiments, the controller may provide the additional capacity of the terminal unit responsively to a change in detected or predicted occupancy. For example, this may be a relevant strategy for occasional high occupancy or high activity levels that would generate moisture during cooling mode operation.
Embodiments of this invention are described herein, include the best mode known to the inventors for carrying out the claims. Variations of the disclosed embodiments may become apparent to those of ordinary skill in the art in light of the present disclosure. The inventors expect that the invention will be practiced using details and variations that are left or our that depart the descriptions herein. Thus, the invention includes modifications, variations, and equivalents of the subject matter recited in the claims appended hereto.
In the present application, the term “terminal unit” is used to describe a particular component of a chilled beam system even though chilled beam units may be identified as “terminal units” by those skilled in the art. In the present application, the term “chilled beam” is used to identify a chilled beam type of terminal unit that includes a heat exchanger and induces flow through the heat exchanger by means of primary air jets.
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The term mixing register is generally used to identify a diffuser or opening with an aspect ratio that is lower than about five. In all embodiments where the use of a mixing register is invoked, by configuration of the chilled beam or the terminal unit, the volume of primary air (including air from the terminal unit) may be increased, for example, when a heating mode signal is generated.
The terms “a” and “an” and “the” and similar terms are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clear from the context of usage. The terms “comprising,” “having,” “including,” and “containing” are open-ended terms that do not preclude additional elements or features unless otherwise indicated. The terms “attached” and “connected” mean partly or wholly contained within, affixed to, integral to, or joined together. Ranges of values include each separate value within the range, unless otherwise indicated and each separate value in the range is indicated by recitation of a range as if separately disclosed. Unless otherwise indicated or clear, methods described herein may be performed in any sequential order. Examples described herein are not intended to introduce limitations to the inventions.
The present application claims the benefit of U.S. Provisional Application 61/297,800, filed Jan. 24, 2010.
Number | Date | Country | |
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61297800 | Jan 2010 | US |
Number | Date | Country | |
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Parent | 13574645 | Jul 2012 | US |
Child | 14266806 | US |