US20150354867A1

Movatterモバイル変換

Info

Publication number: US20150354867A1
Application number: US14/728,545
Authority: US
Inventors: Christopher P. Bloch
Original assignee: Enthaltec Inc
Current assignee: Enthaltec Inc
Priority date: 2014-06-06
Filing date: 2015-06-02
Publication date: 2015-12-10

Abstract

A ventilation adapter unit or roof curb retrofit is provided for reducing energy costs in operating a building ventilation system. The unit is disposed between a traditional HVAC unit and a surface of the building, and has a plurality of internal passageways including a return air passageway, a discharge air passageway, and a supplemental discharge air passageway. Air entering the discharge air passageway from the HVAC unit is selectively routed into the supplemental discharge air passageway, where it is cooled by a cooling panel according to the position of a damper in the discharge air passageway. The cooling panel receives chilled fluid from a chiller, such as an ice storage system that operates a refrigeration unit during off-peak hours. Regardless of whether the air is routed through or around the damper, the air is then discharged from the retrofit unit and into the building.

Description

CROSS REFERENCE TO RELATED APPLICATION

The present application claims the benefit of U.S. provisional application Ser. No. 62/008,775, filed Jun. 6, 2014, which is hereby incorporated by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates generally to ventilation systems for buildings, and more particularly, to adapters or retrofit units for mounting a powered HVAC unit along a building exterior.

BACKGROUND OF THE INVENTION

Heating, ventilation, and air conditioning (“HVAC”) units are typically mounted to building rooftops, or other building exterior surfaces, at a flashed-in “curb” that is made up of a plurality of upraised walls surrounding an opening in the building exterior. Such HVAC units typically include at least a refrigerant-based air conditioning system including a compressor, an evaporator, a condenser, an electric blower, and associated ductwork contained within a main housing, with the unit made weather-resistant for outdoor installations. Optionally, HVAC units may further include a heater, such as electric coils or a gas-fired burner, and may be operable in a fan-only mode for ventilation purposes.

In some cases, and especially when a newer HVAC unit is to be installed at an existing roof curb, a roof curb adapter is placed between the HVAC unit and the roof curb to obviate the need for modifying or re-sealing the roof curb, and also to obviate the need to locate or custom build an HVAC unit having inlets and outlets that dimensionally match the outlets and inlets of an existing roof curb and associated building ductwork.

Electrical rates typically fluctuate according to the time of day and even the day of the week due to changes in demand. For example, utility companies must provide enough electrical generating capacity to meet customer demand during peak consumption times of the day, such as hot summer afternoons. However, energy demands are substantially less during cooler nighttime hours, so that substantial excess capacity is available during those hours, and energy pricing can be reduced substantially during those times. To take advantage of the lower cost energy available during “off hours,” ice storage systems have been developed to create ice or other cooled substances during off hours by operating refrigeration systems associated with the ice storage systems. The formed ice or other chilled material is stored in insulated containers, so that a separate cooling fluid may be circulated through the ice or other chilled substance during peak daytime hours, and then through a heat exchanger in a discharge air duct that supplies air to a building, to thereby cool the building during times when energy cost can be substantially higher. Thus, the cooling capacity of the ice or other chilled substance may be utilized for cooling the building air during peak hours, while reducing or eliminating the need to operate costly energy-consuming air conditioning systems, and especially their refrigerant compressors, during peak hours.

SUMMARY OF THE INVENTION

The present invention provides a modified roof curb adapter or retrofit unit, which permits the substantially conventional use of a rooftop HVAC unit, and which also permits the use of a separate chiller, such as an ice storage unit, to take advantage of lower electricity costs during off-peak hours. The retrofit unit includes a conventional return air passageway that directs warm or stale air from the building into the HVAC unit, but the retrofit unit has a damper or valve disposed along a discharge air passageway so that air received into the HVAC unit can be selectively directed through a supplemental discharge air passageway in the retrofit unit, the supplemental discharge air passageway containing a heat exchanger, such as a cooling panel associated with a chiller.

This arrangement permits the HVAC unit to be operated in a fan-only mode, without energizing a refrigerant compressor of an air conditioning system in the HVAC unit, and to instead cool the air using the cooling panel associated with the chiller, before the discharge air is passed back into the building. However, when the damper or valve is open, the air exiting the HVAC unit is routed directly through the damper or valve and out through the retrofit unit and into the building, substantially bypassing the cooling panel associated with the chiller. By essentially removing the cooling panel from the air stream when the damper or valve is open, the fan efficiency of the HVAC unit is substantially unaffected by the presence of the cooling panel in the retrofit unit, because the air discharged from the HVAC unit is not being routed through the cooling panel that otherwise causes a pressure drop in the airstream and would require higher fan power to maintain a given airflow rate. Accordingly, the HVAC unit may be operated in a conventional manner as desired, and may be operated in a fan-only mode in which air is not being cooled by the HVAC unit, but instead the air is routed along the supplemental discharge air passageway in the retrofit unit, where it passes through the cooling panel associated with the chiller, so that energy consumed by the chiller during off-peak hours may be used during on-peak hours to provide cooled air to the building during on-peak hours, as desired.

Optionally, the first end portion of the housing is a lower end that engages a roof curb at the top of the building, and the second end portion of the main housing is an upper end that receives the powered ventilation unit.

Optionally, the damper includes one or more pivotable louvers and a powered actuator that pivots the louvers in response to a damper activation signal. The damper may be oriented along a diagonal (i.e. neither perpendicular nor parallel to outer walls of the retrofit unit), with a first end portion located proximate the first end portion of the main housing, and a second end portion located proximate the second end portion of the main housing.

Optionally, the interior walls include a first wall that is positioned between the damper and the inlet portion of the supplemental discharge air passageway, the first interior wall defining a generally triangular opening at the inlet portion of the supplemental discharge air passageway.

Optionally, the heat exchanger is a cooling panel having fluid conduit that is in fluid communication with a chiller, such as an ice storage unit associated with the building and operable during off-peak hours to create ice or other chilled material or substance, which can later be used to cool a fluid that is directed through the cooling panel at times when air cooling is desired, particularly during on-peak hours of higher energy costs.

Optionally, a controller is used to selectively actuate the damper to its closed position, and to activate the chiller to circulate chilled fluid through the cooling panel as air passes through the supplemental discharge air passageway and the cooling panel. The controller may be operable in response to one or more of a thermostat located in a room of the building, a real time clock, and a chiller status signal. The controller may further be operable to selectively energize the blower and compressor-based air conditioner of the powered ventilation unit. The controller may further be operable to simultaneously energize the blower of the powered roof top ventilation unit, de-energize the air conditioner of the powered rooftop unit, actuate the damper to the closed position, and activate the chiller.

Thus, the ventilation adapter unit or roof curb retrofit unit of the present invention facilitates the use of lower-priced energy during off-peak periods, and lowering energy consumption during on-peak periods, but without significantly increasing the energy consumption of a blower fan associate with a conventional HVAC unit, since a cooling panel or heat exchanger associated with the retrofit unit is essentially removed from the airstream during periods when it is not in use. The retrofit thus facilitates the installation of new HVAC units along a building exterior, without substantially affecting the operating efficiency of the HVAC unit, and by facilitating reduced usage of the HVAC unit during periods of peak energy rates or prices, by cooling discharge air using a chiller that primarily consumes energy during off-peak hours while deactivating or limiting the use of a compressor-based air conditioner associated with the HVAC unit.

These and other objects, advantages, purposes and features of the present invention will become apparent upon review of the following specification in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified diagrammatic view of an HVAC system for a building, including a roof curb retrofit unit in accordance with the present invention;

FIGS. 2-5 are a series of top perspective views of the roof curb retrofit unit ofFIG. 1, taken from different viewing angles; and

FIG. 6 is a top plan view of the roof curb retrofit unit.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings and illustrative embodiments depicted therein, a ventilation adapter unit in the form of a roofcurb retrofit unit10 is configured for mounting atop abuilding12, between aroof curb14 and an HVAC unit16 (FIG. 1), although non-rooftop mounting locations are equally possible.Retrofit unit10 has amain housing18 with a first orlower end portion18athat rests atoproof curb14, and a second orupper end portion18bthat supportsHVAC unit16.Main housing18 defines an inner chamber or region, which is divided into a plurality of passageways by interior divider walls. The passageways defined bymain housing18 include areturn air passageway20, adischarge air passageway22, and a supplemental discharge air passageway24 (FIGS.1 and3-6).Discharge passageway22 contains a damper orvalve26 that is operable to selectively direct discharge air received fromHVAC unit16 into supplementaldischarge air passageway24, which contains a heat exchanger in the form of acooling panel28, as will be described in more detail below.

Main housing

18 has exterior surfaces made up of a plurality of panels, typically of sheet metal, including afirst end wall30a, asecond end wall30b, afirst sidewall32a, asecond sidewall32b, and a generally L-shaped bottom wall34 atlower end portion18aalong supplemental discharge air passageway24 (FIGS. 3-6). Optionally, a generally L-shaped top wall, corresponding tobottom wall34, can be positioned atupper end portion18bof the main housing, to enclose the supplementaldischarge air passageway24. A firstinterior divider wall36 is positioned betweendischarge air passageway22 and an intake end portion of supplementaldischarge air passageway24, and a secondinterior divider wall38 is positioned on the opposite side ofdischarge air passageway22 fromfirst wall36, and separatesreturn air passageway20 fromdischarge air passageway22. First and

second divider walls

26,38 are generally parallel to first and

second end walls

30a,30b.

A thirdinterior divider wall40 is generally parallel to first and

second sidewalls

32a,32b, with first and second

interior divider walls

36,38 terminating at third interior divider wall40 (FIGS. 3-6). In the illustrated embodiment, first and

second divider walls

36,38 extend inwardly fromfirst sidewall32a, with firstinterior divider wall36 having anextension portion36aprojecting further towardsecond sidewall32bto accommodatecooling panel28. However, it will be appreciated that the size and placement ofcooling panel28, and of the various sidewalls in the main housing, may be changed as desired for a particular application, without departing from the spirit and scope of the present invention.

Thirdinterior divider wall40 defines anopening42 between first and second

interior divider walls

36,38, and below anupper end portion26aof damper26 (FIGS. 3 and 4).Damper26 is set at a diagonal angle, so that itsupper end portion26ais positioned alonginterior divider wall40, while alower end portion26bis positioned alongfirst sidewall32aat L-shaped bottom wall34. As will be described in more detail below, whendamper26 is open, such as shown inFIGS. 2-6, discharge air enteringdischarge air passageway22 atupper end portion18awill pass substantially uninhibited throughdamper26 and out through adischarge opening44 formed inlower end portion18a, between first and

second divider walls

36,38. Whendamper26 is closed, discharge air is routed through a generallytriangular opening46 and into supplementaldischarge air passageway24, where it passes throughcooling panel28, whereupon it is directed out throughdischarge opening44 viaopening42 formed in thirdinterior divider wall40. Thus, whendamper26 is closed, discharge air in thedischarge air passageway22 is forced arounddamper26 and throughcooling panel28, rather than directly throughdamper26, although it will be appreciated that the discharge air eventually exits through the same discharge opening44 regardless of the position ofdamper26.

Referring again toFIG. 1, returnair passageway20 receives warm or stale air from building12 via areturn air duct48 having aninlet48ainside the building, and having anoutlet48bin theroof curb14. Similarly, all discharge air enteringdischarge air passageway22 exits throughdischarge opening44 and into adischarge air duct50 having aninlet portion50aatroof curb14, and anair outlet portion50bin a room of building12. Return air exitingreturn air passageway20 atupper end portion18aof the main housing passes into anintake duct52, passes through a heat exchanger such as anevaporator54 that receives refrigerant from a compressor56. A condenser would also be included, and a fresh air intake and/or heater are optional, but are omitted from the drawing for clarity. It will further be appreciated that, instead of a refrigerant-based cooling system, the HVAC unit could utilize an evaporative cooling system, a piezoelectric cooling system, or substantially any other type of heat exchanger, without departing from the spirit and scope of the present invention.

After passing throughevaporator54, which may or may not be actively operating to cool the air received throughintake duct52, the air enters adischarge duct58 containing ablower fan60, which draws the air throughreturn air duct48,intake duct52,discharge duct58, and directs the discharge air intodischarge air passageway22 ofretrofit unit10 and, subsequently, intodischarge air duct50 and into the room of the building. It is desirable thatblower fan60 is operable independently of compressor56 so thatHVAC unit16 may be operated in a relatively low-energy state by running onlyblower fan60 for ventilation and subsequent cooling by thecooling panel28 ofretrofit unit10. This permits discharge air to be cooled only by coolingpanel28 whendamper26 is closed.

Coolingpanel28 is another heat exchanger that receives chilled fluid via a coldfluid inlet line62a, which originates at a chiller such as anice storage unit64 located in ornearby building12. Typically, the chilled fluid passes through coils or a series of fluid passageways of coolingpanel28, absorbing heat from the airstream as the air passes throughsupplemental discharge passageway24. The fluid then exits through afluid outlet line62a, which leads back toice storage unit64 for re-cooling and recirculation back to coolingpanel28.

Acontroller66 is operable to controlHVAC unit16,damper26, andice storage unit64.Controller66 is in communication withHVAC unit16 via anHVAC control line68, is in communication with a powered actuator associated withdamper26 via adamper control line70, and is in communication withice storage unit64 via achiller control line72. Preferably,controller66 is operable to independently energize and de-energize compressor56 andblower fan60 ofHVAC unit16, repositiondamper26 in the open or closed position as needed, and to activateice storage unit64 by operating a fluid pump to direct chilled fluid into coolingpanel28 via coldfluid inlet line62a. In addition,controller66 may include or be in communication with a real time clock, and with athermostat74 positioned in a room of the building. Optionally, the controller may be in wireless communication with the various components that it controls and/or from which it receives data that is uses to determine the appropriate operating configuration.

To operateHVAC unit16,retrofit unit10, andice storage unit64 in a cost-efficient and optimized manner,controller66 is programmed to operateice storage unit64 during off-peak hours when energy costs are lower, such as at night, and during thattime controller66 may rely on compressor56 andevaporator54 ofHVAC unit16 to provide the necessary cooling of discharge air throughdischarge air passageway22, withdamper26 open. Optionally, cooling may also be supplemented by coolingpanel28 during off-peak hours, if desired and if cooling capacity remains inice storage unit64. During periods of high energy costs, such as during summer daytime hours,controller66 is programmable to operateice storage unit64 to pump chilled fluid through coolingpanel28, and to operateblower fan60 without operating compressor56, withdamper26 actuated to a closed position to direct the discharged air through supplementaldischarge air passageway24 and coolingpanel28, thereby utilizing the cooling capacity ofice storage unit64 during periods of peak energy costs.Controller66 may receive a status signal fromice storage unit64, the status signal being indicative of the remaining cooling capacity ofice storage unit64, so thatcontroller66 can revert to normal operation ofHVAC unit16 by operating compressor56 andopening damper26 to bypass coolingpanel28 when the cooling capacity ofice storage unit64 has been depleted. It is envisioned that ifice storage unit64 retains cooling capacity after the conclusion of a high cost energy time of day,controller66 may continue to circulate fluid fromice storage unit64 throughcooling panel28 until its cooling capacity has been depleted. By programmingcontroller66 with the times of day at which energy costs are highest and lowest,controller66 will operateretrofit unit10,HVAC unit16, andice storage unit64 in a manner that minimizes the cost of energy utilized in cooling interior rooms ofbuilding12.

Although the ventilation adapter or retrofit unit of the present invention is primarily described herein as a rooftop unit that operates in a coordinated manner with a powered rooftop ventilation system or unit, it will be appreciated that the ventilation adapter or retrofit unit may be installed along substantially any exterior wall or surface of a building, such as for use with a wall-mounted ventilation system. The ventilation adapter or retrofit unit may also be adapted for use in a building interior. It will further be appreciated that the ventilation adapter or retrofit unit can be readily adapted to supplement a building's heating instead of (or in addition to) the building's cooling, in substantially the same manner as described above, such as by circulating warm fluid through the retrofit unit's heat exchanger panel. In such an arrangement, the warm fluid may be created by solar heating or with electricity or other energy source during times of lower energy cost, and circulated through the heat exchanger panel during times of higher energy cost.

Therefore, the present invention provides a ventilation adapter unit or roof curb retrofit that minimizes the consumption of high cost electrical energy during peak usage times of day, by offsetting some of that energy usage with increased energy usage during lower cost times of day. An ice storage system or the like is operated during low cost periods, so that chilled fluid may be circulated through a cooling panel in the retrofit unit during high energy costs times, but substantially without increasing the energy required to force discharge air through the cooling panel during times when it is not in use. The retrofit unit is operable in coordinated manner with the HVAC unit and with the ice storage system, substantially automatically, to minimize energy costs for a particular installation.

Changes and modifications in the specifically-described embodiments may be carried out without departing from the principles of the present invention, which is intended to be limited only by the scope of the appended claims as interpreted according to the principles of patent law including the doctrine of equivalents.

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A ventilation adapter unit for a building ventilation system, said adapter unit comprising:

a main housing defining an inner chamber, said main housing including first and second end portions, said first end portion configured to engage an exterior building surface associated with the building ventilation system, and said second end portion configured to engage a powered ventilation unit of the building ventilation system;

a plurality of interior walls dividing said inner chamber into a plurality of passageways including (i) a return air passageway open at both said first and second end portions of said main housing, (ii) a discharge air passageway open at both said first and second end portions of said main housing, and (iii) a supplemental discharge air passageway having an inlet portion in fluid communication with said discharge air passageway near said open second end portion of said main housing and an outlet portion in fluid communication with said discharge air passageway near said open first end portion of said main housing;

a heat exchanger disposed in said supplemental discharge air passageway; and

a damper disposed in said discharge air passageway between said first and second end portions of said main housing and positionable between an open position and a closed position;

wherein when said damper is in the open position, a flow of discharge air is permitted to pass from the powered ventilation unit through said second end portion of said main housing and substantially directly out through said first end portion of said main housing, and when said damper is in the closed position, the flow of discharge air is directed into said supplemental air passageway, through said heat exchanger, and out through said first end portion of said main housing.

2. The ventilation adapter unit ofclaim 1, wherein said damper is oriented along a diagonal with a first end portion located proximate said first end portion of said main housing and a second end portion located proximate said second end portion of said main housing.

3. The ventilation adapter unit ofclaim 2, wherein said plurality of interior walls comprises a first interior wall positioned between said damper and said inlet portion of said supplemental discharge air passageway, and wherein said first interior wall defines a generally triangular opening at said inlet portion of said supplemental discharge air passageway.

4. The ventilation adapter unit ofclaim 1, wherein said heat exchanger comprises a cooling panel in fluid communication with a chiller.

5. The ventilation adapter unit ofclaim 4, further in combination with the chiller, wherein said chiller comprises an ice storage unit.

6. The ventilation adapter unit ofclaim 4, further comprising a controller, wherein said controller is operable to selectively actuate said damper to the closed position and to activate the chiller to thereby circulate chilled fluid through said cooling panel.

7. The ventilation adapter unit ofclaim 6, wherein said controller is operable in response to at least one chosen from (i) a thermostat located in a room of the building, (ii) a real time clock, and (iii) a chiller status signal.

8. The ventilation adapter unit ofclaim 7, wherein said controller is further operable to selectively energize a blower and an air conditioner of the powered ventilation unit.

9. The ventilation adapter unit ofclaim 8, wherein said controller is operable to simultaneously (i) energize the blower of the powered rooftop ventilation unit, (ii) de-energize the air conditioner of the powered rooftop ventilation unit, (iii) actuate said damper to the closed position, and (iv) activate said chiller.

10. A roof curb retrofit unit comprising:

a main housing comprising perimeter walls that cooperate to define an inner chamber, a lower portion for engaging a roof curb, and an upper portion for engaging a powered rooftop ventilation unit;

a plurality of interior walls dividing said inner chamber into a plurality of passageways including (i) a return air passageway open at both said upper and lower portions of said main housing, (ii) a discharge air passageway open at both said upper and lower portions of said main housing, and (iii) a supplemental discharge air passageway having an inlet portion in fluid communication with said discharge air passageway near said open upper portion of said main housing and an outlet portion in fluid communication with said discharge air passageway near said open lower portion of said main housing;

a cooling panel disposed in said supplemental discharge air passageway between said inlet and outlet portions thereof, said cooling panel configured to permit a flow of air therethrough and to remove heat from the air; and

a damper disposed in said discharge air passageway between said upper and lower portions of said main housing, wherein said damper is configurable between an open position and a closed position;

wherein when said damper is in the open position, a flow of discharge air is permitted to pass from the rooftop ventilation unit through said upper portion of said main housing and substantially directly out through said lower portion of said main housing, and when said damper is in the closed position, the flow of discharge air is directed into said supplemental air passageway, through said cooling panel, and out through said lower portion of said main housing.

11. The roof curb retrofit unit ofclaim 10, wherein said main housing comprises a bottom panel attached to said perimeter walls, said bottom panel defining openings only at said return air passageway and at said discharge air passageway.

12. The roof curb retrofit unit ofclaim 11, wherein said damper is oriented along a diagonal relative to a horizontal plane, and comprises an upper end portion proximate said upper portion of said main housing and a lower end portion proximate said lower portion of said main housing.

13. The roof curb retrofit unit ofclaim 10, wherein said plurality of interior walls comprise a first interior wall positioned between said damper and said inlet portion of said supplemental discharge air passageway, and wherein said first interior wall defines a generally triangular opening at said inlet portion of said supplemental discharge air passageway.

14. The roof curb retrofit unit ofclaim 10, wherein an entirety of the flow of discharge air entering said discharge air passageway passes through said damper or said cooling panel.

15. The roof curb retrofit unit ofclaim 10, wherein said cooling panel is in fluid communication with a chiller.

16. The roof curb retrofit unit ofclaim 15, further comprising a controller, wherein said controller is operable to selectively actuate said damper to the closed position and to activate the chiller to thereby circulate chilled fluid through said cooling panel.

17. The roof curb retrofit unit ofclaim 16, wherein said controller is operable in response to at least one chosen from (i) a thermostat located in a room of a building on which said roof curb retrofit unit is mounted, (ii) a real time clock, (iii) a chiller status signal.

18. The roof curb retrofit unit ofclaim 17, wherein said controller is further operable to selectively energize a blower and an air conditioner of the powered rooftop ventilation unit.

19. The roof curb retrofit unit ofclaim 18, wherein said controller is operable to simultaneously (i) energize the blower of the powered rooftop ventilation unit, (ii) de-energize the air conditioner of the powered rooftop ventilation unit, (iii) actuate said damper to the closed position, and (iv) activate said chiller.

20. A method of operating a roof curb retrofit unit, said method comprising:

directing return air from a building interior to a return air passageway of the roof curb retrofit unit;

directing the return air from the return air passageway to a powered rooftop ventilation unit coupled to the roof curb retrofit unit;

passing the return air through a blower of the powered rooftop ventilation unit to convert the return air to discharge air;

directing the discharge air from the powered rooftop ventilation unit to a discharge air passageway of the roof curb retrofit unit;

closing a damper that is disposed in the discharge air passageway to thereby direct the discharge air (i) into an inlet portion of a supplemental discharge air passageway of the roof curb retrofit unit that is in fluid communication with the discharge air passageway, (ii) through a cooling panel disposed in the supplemental discharge air passageway, and (iii) out of the roof curb retrofit unit through an outlet portion of the discharge air passageway;

opening the damper to thereby direct the discharge air through the damper and directly to the outlet portion of the discharge air passageway so that the discharge air substantially bypasses the supplemental discharge air passageway; and

circulating a cooling fluid through the cooling panel when the damper is closed.