BACKGROUND OF THE INVENTION
The present disclosure is generally related to open-case refrigeration technologies, and more specifically a retrofit energy device and system to modify, manipulate and optimize airflow in vertical open-case refrigeration units.
Retailers frequently use open-case refrigeration for some or all of their refrigerated items. Open-case refrigerators can be found in virtually every grocery store, supermarket, and convenience store around the world. These units contain dairy, meats, prepared foods, perishable food and beverages, keeping them cold while displaying them in a manner that is attractive and inviting to customers. One downside of vertical open-case refrigerators is that as with all cooling devices, they inherently use a lot of power, but in addition, their open fronts are extremely inefficient, resulting in high energy bills, losing on average 75% of the energy used to operate it primarily due to infiltration of warm ambient air.
One prior method to overcome the deficiencies of vertical open-case refrigeration units has been to use customized retrofit shelving to replace the existing shelves which re-circulates air through a complex series of channels built into them. However, this method employs a process that is both disruptive to retail operations and very costly to implement due to its complexity.
Another prior method is to retrofit vertical open-case refrigeration units with doors to achieve energy savings. However, opening a physical door pulls cold air out of the case as it breaks the seal within the refrigerated space. For example, one study showed that when a refrigeration unit's door is opened over 60 times in one hour, it negates any energy savings gained. On average doors reduce power used by 25%, according to studies, while having a long payback of 5-7 years.
One major issue for retailers in determining power use and savings is that most manufacturers test and develop their products in laboratory conditions with stagnant air and no products on the shelves, which do not take into account the rigors and air movements that occur in the real world from normal ambient activities. A person walking by a vertical open case refrigeration unit can create warm air intrusion that raises the temperature entering a Return Air Grill (RAG) by as much as 50%, and can take as long as 30 seconds to recover. A full refrigeration unit responds differently to one that is half full.
Opening doors can also be cumbersome in high traffic areas or crowded spaces, and hidden costs include elevated maintenance, as the doors require frequent cleaning and the windows need de-fogging technologies, which use more energy. There is also a substantial cost and disruption to retail operations associated with retrofitting open-case refrigeration units with doors. Furthermore, some studies have shown that placing a physical barrier between the customer and the product leads to reduced sales, and this loss negated the energy savings that the doors provided. Commercial retailers therefore still make extensive use of open refrigeration units despite their substantial inefficiencies.
SUMMARY OF THE INVENTION
The following presents a simplified summary of the innovation in order to provide a basic understanding of some aspects of the invention. This summary is not an extensive overview of the invention. It is intended to neither identify key or critical elements of the invention nor delineate the scope of the invention. Its sole purpose is to present some concepts of the invention in a simplified form as a prelude to the more detailed description that is presented later.
The present invention provides methods and apparatus for a retrofit energy device and system to modify, manipulate and optimize airflow in vertical open-case refrigeration units.
In one aspect, the invention features an open refrigerated display case including a refrigerated display area comprising one or more shelves, an air outlet and an air inlet opening into the display area and spaced from one another, and a duct configured to direct air flow out of the air outlet across the display area and toward the air inlet to form an air curtain across the display area, each one or more shelves provided with an airflow device attached in front of an outflow point of the air curtain.
In another aspect, the invention features a refrigeration system including a display case having an open front for allowing access thereto and being capable of having shelves arranged therein, cooling means arranged along the top of a refrigeration system, first air passage means arranged for receiving air passing through the cooling means and carrying refrigerated air therefrom to the display case, and means for establishing an air curtain, said air curtain extending substantially vertically across the opening in said display case, wherein one or more of the shelves is provided with an airflow device attached in front of an outflow point of the air curtain.
Embodiments of the invention may have one or more of the following advantages.
A retrofit airflow device and features for airflow manipulation that can be attached onto most state of the art vertical open-case refrigeration units in existence.
A retrofit airflow device located in front of the DAG reduces energy waste and warm air infiltration by maintaining a parallel ambient air curtain that minimizes the mixing of cold and ambient streams while providing the cold curtain additional momentum to travel further with minimal disruption.
A retrofit airflow device that can be attached to one or more individual shelves and create separation between the interior cavity of the shelf and the DAG air curtain flow and ambient air, thus creating a more energy efficient seal.
A retrofit solution where when the DAG area airflow device and shelving airflow devices are deployed, both combined improve the overall energy efficiency of the vertical open-case refrigeration system.
A retrofit solution that can be configured to create separation of the cold air inside the shelves and the warm ambient air without a creating a physical barrier between the product and consumer that can negatively impact retail sales.
A retrofit solution that does not require replacement of existing shelving or other parts of the original refrigeration unit, which can affect cost, time for installation and potentially negatively impact the open case refrigerators original manufacturer's warranty.
A retrofit solution which may use state of the art smart thermostat systems to assist in optimizing the improved cooling environment inside the shelving cavities.
A retrofit solution which can overall reduce the temperature of the shelves by improving the overall efficiency of the host vertical open case refrigeration unit.
A retrofit solution that may use simple blocking methods to reduce the air volume being released from the rear of the shelves to reduce overflow of cold air at the intake of the refrigerator case discharge air grill (RAG).
A retrofit system that can plug directly into a wall plug using standard power converters to eliminate the need for costly electrical installers.
A retrofit solution that targets the reduction in the number and length of the cooling cycles and the duty cycle of the host refrigeration unit to reduce its operating time and thus its energy use.
A retrofit solution that by reducing the operating cycles of vertical open-case refrigeration units can extend the operating life of these units.
A retrofit system that uses airflow speeds between 0.3 m/s to 3 m/s on average to operate and can be modified to meet a host refrigeration units specific operating parameters.
A retrofit solution that uses one or multiple low-power cross flow impeller fans or blower wheels which are housed in retrofit devices which are designed to optimize the airflow they generate and can be manipulated in velocity, density and direction to meet the operating parameters of its host refrigeration unit.
A retrofit solution which can be configured with other passive methods to stabilize and optimize airflow.
A retrofit solution which in some cases effectively reduces the difference in air temperatures between the RAG and DAG to as little as under 1 degree C., allowing the condenser to not use as much power to accomplish a reduction in the air temperature.
A retrofit housing that can be easily opened to access and replace a removable motor that operates the airflow impellers.
A retrofit housing that can be easily opened to access and replace removable airflow impellers in the event of damage.
A new vertical open case refrigeration design can integrate the fundamental operating parameters that are being accomplished by the various airflow devices, features, configurations, signature airflow patterns and characteristics of this invention.
These and other features and advantages will be apparent from a reading of the following detailed description and a review of the associated drawings. It is to be understood that both the foregoing general description and the following detailed description are explanatory only and are not restrictive of aspects as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be more fully understood by reference to the detailed description, in conjunction with the following figures, wherein:
FIG. 1A is a diagram of a side view of an illustrative state of the art vertical open-case refrigerator after the compressor cycle activates (turns on) and it releases cold air from its air curtain to sustain its temperature.
FIG. 1B is a diagram of a side view of an illustrative state of the art vertical open-case refrigerator after the compressor cycle activates (turns on) as it releases cold air from its air curtain with attached airflow device(s) in accordance with an embodiment of the present disclosure.
FIG. 2A is a computer modeling (CFD) showing cold air loss and ambient air infiltration from an illustrative state of the art vertical open-case refrigerator as the compressor cycle activates and releases cold air from its air curtain.
FIG. 2B is an illustration of a thermal image of a state of the art vertical open-case refrigerator as the compressor cycle activates and releases cold air from its air curtain with an airflow device of this invention attached in accordance with an embodiment of the present disclosure.
FIG. 3A is a diagram of a side view of an illustrative state of the art vertical open-case refrigerator with cold air being released from its air curtain at the top and from the rear of the shelving units.
FIG. 3B is a diagram of a side view of an illustrative state of the art vertical open-case refrigerator with cold air being released from its air curtain at the top and from the rear of the shelving units. It also shows airflow devices of this invention attached at the entry point of the air curtain and on the ends of the individual shelves in accordance with an embodiment of the present disclosure.
FIG. 4 is an illustrative side view of a state-of-the-art vertical open-case refrigeration unit with one embodiment of this invention showing airflow devices of this invention attached at the entry point of the air curtain and on the penultimate/last shelf.
FIG. 5 is an illustrative side view of a state-of-the-art vertical open-case refrigeration unit with another embodiment of this invention showing airflow devices of this invention attached at the entry point of the air curtain and on the penultimate/last shelf, and retractable doors across the opening of the last shelf.
FIG. 6 shows an illustration of an enhanced IR image of the side of the vertical open case refrigerator unit with embodiment of FIG. 3A, showing flow of the air curtain spilling over the bottom of the open area of the unit.
FIG. 7 shows an illustration of an enhanced IR image of the side of the vertical open case refrigerator unit with embodiment of FIGS. 4 and 5, showing further improvement in air curtain shape and performance.
FIG. 8 is a diagram of a side view of an illustrative airflow device and housing in accordance with an embodiment of the present disclosure attached next to the DAG area of a vertical open-case refrigerator unit.
FIG. 9 is a diagram of a side view of an illustrative airflow device and housing in accordance with an embodiment of the present disclosure attached to the end of a shelf of an open-case refrigerator.
FIG. 10 is a diagram of a perspective view of an illustrative airflow device in accordance with an embodiment of the present disclosure attached to the end of shelf of a vertical open-case refrigerator. It shows the air intakes and outflows.
FIG. 11 is a diagram of a perspective view of an illustrative airflow device in accordance with an embodiment of the present disclosure attached to the end of multiple shelves of a vertical open-case refrigerator. It shows that the airflow devices extend along the horizontal length of the front of each shelf.
FIG. 12 is an illustrative perspective view of one possible embodiment of an airflow device and housing of the present disclosure illustrating various component of the airflow device.
FIG. 13 is an illustrative perspective view of one possible embodiment of an impeller of an airflow device of the present disclosure illustrating various component of the impeller.
FIG. 14 is an illustrative perspective view of one possible embodiment of a removable and replaceable electrical motor connected to an impeller of an airflow device of the present disclosure illustrating the assembly.
FIG. 15 is an illustrative perspective view of one possible embodiment of a removable and replaceable flow conditioner used in an airflow device of the present disclosure illustrating the features and details thereof.
FIG. 16 is an illustrative perspective view of one possible embodiment of the doors used as part of the present disclosure illustrating the features and details thereof.
FIG. 17A is an illustrative side view of one possible alternative embodiment of the invention of the present disclosure showing the use of an air vent duct instead of a Shelf Fan to redirect air into the RAG area.
FIG. 17B is an illustrative side view of one possible alternative embodiment of the invention of the present disclosure showing the details of the air vent duct.
FIG. 17C is an illustrative perspective view of one possible alternative embodiment of the invention of the present disclosure showing the details of the air vent duct.
DETAILED DESCRIPTION
The subject innovation is now described with reference to the drawings, wherein like reference numerals are used to refer to like elements throughout. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It may be evident, however, that the present invention may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form in order to facilitate describing the present invention.
In addition, the term “or” is intended to mean an inclusive “or” rather than an exclusive “or.” That is, unless specified otherwise, or clear from context, “X employs A or B” is intended to mean any of the natural inclusive permutations. That is, if X employs A, X employs B, or X employs both A and B, then “X employs A or B” is satisfied under any of the foregoing instances. Moreover, articles “a” and “an” as used in the subject specification and annexed drawings should generally be construed to mean “one or more” unless specified otherwise or clear from context to be directed to a singular form.
The present invention provides a compact energy efficiency device and system to modify, manipulate and optimize airflow in order to reduce energy use in open-case refrigeration units by creating a specific airflow characteristic and shape pattern. More specifically, the objectives of this device or devices are to produce a balanced combination of particular airflow pattern characteristics, optimize, redirect, change velocity and strengthen the airflow within state of the art vertical open case refrigeration units. Since the airflow characteristics are unique, the application can be universally applied across a diverse number of vertical open case refrigeration designs and manufacturers, including both new and retrofit applications.
Individual impacts of this invention include the reduction of warm air intrusion by improving the recovery time strengthening the air curtain near the Discharge Air Grill (DAG) and upper half of the open case refrigerator; using a secondary airflow device reducing cold air loss from the host air curtain by redirecting it and optimizing the velocity as it approaches the final shelf prior to the RAG; producing a signature airflow pattern; reduce the volume of warm air intrusion into the RAG by strengthening the curtain near the intake using passive or active devices. By reducing the temperature of the air entering the RAG, the host unit's compressor does not need to expend as much power and operate for as long a period to reduce the air temperature being released at the DAG.
Systems according to the present disclosure can help to reduce substantial energy costs exhibited by prior-art vertical open refrigeration units or display cases in retail establishments. The cost reductions can be very significant given the large numbers of units in operation and the high levels of energy that they consume. These cost reductions can result from better containment of the cold air, optimized airflow patterns and reduction of the intrusion of the warmer ambient air, which reduces the power consumption of the unit to maintain its optimal operating temperatures.
To put the potential cost savings into perspective, most people consider the cost of air conditioning a home one of the largest electricity expenses, and a typical 1000 square foot (sf) home can be cooled with a 1 ton air conditioner which uses about 1000 watts to operate it. In contrast, a typical 4 foot length, state of the art vertical open case refrigeration unit will use 1,300-1,600 watts to power it. A typical 1,000 sf convenience store in most countries will contain 40 linear feet of open case refrigeration. So the cost of powering an open case refrigeration system is over ten times the cost of air conditioning the same space.
FIG. 1A is a diagram of a side view of an exemplary vertical open-case refrigerator after the compressor cycle activates. The air circulates through the refrigeration unit 100 as it is cooled and is slowly released through the outflow point of the air curtain Discharge Air Grill (DAG) 101. Simultaneously, air is released from the rear panels 102 of the refrigeration unit, which cools the product placed in the cavity of the shelving. As the air is released from the air curtain it mixes in with the warmer ambient air 103 as it gradually organizes itself to eventually create a more stable downward motion to help seal the open cavities of the shelves. As the cold air moves towards the opening of the shelves, it continues flowing in an outward and downward direction 104. At the bottom of the unit, there is an input Return/Receive Air Grill (RAG) 105 where the air is re-captured and cooled before it is released to the shelves and the DAG 101. The inefficiency of the system creates a substantial overflow of cold air 106 which is a large portion of the energy loss.
FIG. 1B is a diagram of a side view of an exemplary vertical open case refrigerator after the compressor cycle activates as it releases cold air from its air curtain. In this illustration, an airflow device 110 of the present invention is attached in front of the outflow point of the air curtain DAG. 111 The speed of the airflow 112 from the airflow device must be matched or similar to the airflow speed 113 being released from the refrigeration unit's air curtain (DAG) to avoid shear, which will result in warm air intrusion. As the upper airflow device of this invention is active in perpetuity, it substantially reduces the losses associated with state of the art vertical open-case refrigeration systems due to cold air spillage and warm air infiltration, by strengthening the existing air curtain and in the event of warm air intrusion, a much faster temperature recovery time, often in half the time. Airflow from the air curtain is immediately contained and the result has been that the air entering the RAG 114 is colder, while reducing the cold air overflow 115. Temperatures being released from the DAG 111 are colder as are the individual temperatures in the shelving spaces using this type of airflow management system using the devices in this invention. In case studies, the difference between the RAG and DAG has been as little as under 1 degree Centigrade (C).
FIG. 2A is an illustrative computer modeling (CFD) showing cold air loss and warm ambient air infiltration from an illustrative state of the art vertical open-case refrigerator, as the compressor cycle activates and releases cold air from its air curtain 200. As the airflow attempts to organize, substantial losses of cold air occur 201, while facilitating warm air infiltration 202 which is shown as a lighter shade entering the RAG 203.
FIG. 2B is an illustration of a thermal image of an exemplary vertical open-case refrigerator as the compressor cycle activates and releases cold air from its air curtain with an airflow device 210 attached in accordance with an embodiment of the present disclosure. The cold air curtain is seen to be pushed inwards such that half 211 of the curtain is getting sucked back into the RAG, while the other half 212 spilling out of the unit due to watershed effect from the back panel flow 213 bottom two shelves.
FIG. 3A is a diagram of a side view of an exemplary vertical open-case refrigerator with cold air being released from its air curtain 300 and from the rear of the shelving units 301. As the air curtain from the DAG 300 descends it tends to move outwards allowing a greater mixing of cold air 303 with ambient warm air towards the bottom of the unit. The less organized the air curtain, the greater the infiltration of warm ambient air. The state of the art open nature of individual shelves releases substantial volumes of cold air, which then adds to the overflow at the entry point of the RAG 304. A clearer diagram of this shape and effect is illustrated in FIG. 6
FIG. 3B is a diagram of a side view of an exemplary vertical open-case refrigerator with cold air being released from its air curtain 310 and from the rear of the shelving units 311. It also shows airflow devices of this invention attached at the entry point of the air curtain 312 and on the ends of the individual shelves 313 in accordance with an embodiment of the present disclosure. The airflow from the device in front of the air curtain outflow 314 is shown containing the airflow from the air curtain 315 and creating separation. The airflow devices located at the end of the shelves 313 improve the containment of the air inside each shelf cavity, reducing the overflow 316 and improving the cooling of products on each shelf. The reduction of overflow from the shelves will reduce the overflow and mixing of cold air going into the RAG 317.
In laboratory environments, the strengthening of the cold air curtain with an airflow device of this invention does a good job of containing the top 3 shelves. Individual shelf fans for these shelves although effective may be cost prohibitive if the marginal power savings doesn't justify the additional cost of materials and installation.
FIG. 4 shows an alternate embodiment of the current invention which in certain cases optimizes the energy gains against the product/installation cost. This embodiment uses only two airflow devices. One airflow device 401 near the top of the unit intakes ambient air and creates an airflow 402 that runs parallel to the cold air curtain 403 created by the DAG 404. The DAG airflow has matching or similar velocity to that of the cold air curtain. This velocity matching or similar speed reduces shear between the curtain and the airflow generated by this invention and reduces the mixing between cold and warm air temperatures. The second airflow device 405 is attached at the outer edge of the penultimate/last shelf 406, which intakes the cold air 407 being discharged from the rear panel of that shelf as well as the compacted cold air 408 descending from the main cold air curtain. This fan re-directs these two streams and infuses the cold air 409 and directs it towards the RAG 410. This has the combined effect of pushing the slightly warmer air away from the RAG (since cold air is denser) and replacing it with colder air, thus reducing the temperature of the air 411 going into the RAG. The shelf fan also relieves some of the outward pressure created by the back flow and reduces the watershed effect which pushes the main curtain 403 outwards in other state of the art units that are not fitted with the devices of this invention. The inventors of this disclosure have observed and demonstrated this effect via infrared visualization techniques. The effect of this and the airflow shape it produces is clearly is illustrated in FIG. 7.
The inventors of the current disclosure have further observed that most of the cold-and-warm air mixing happened very close to the RAG, roughly across the vertical height of the last shelf. This is expected since the integrity of the DAG cold air curtain starts disintegrating beyond the third shelf, (unless re-directed by a secondary shelf fan) and the cumulative back flow from the previous shelves creates a watershed effect pushing the cold air curtain outwards thus compromising its integrity.
FIG. 5 shows another embodiment of the current invention that improves upon the embodiment of FIG. 4. The embodiment of FIG. 4 still allows some warmer air 412 to get into the RAG. The embodiment of FIG. 5 virtually eliminates this problem by introducing a physical barrier in the form of a see through door 512 across the opening of the bottom shelf all the way to the RAG outside edge. This ensures that the RAG only receives the cold air 509 from the shelf fan 505 installed on the penultimate/last shelf 506, thus further reducing the final temperature of the air 511 entering the RAG 510. As a result of this, during the period when the compressor is in the off cycle, the difference between the RAG and DAG temperatures would go as low as under 1 degree centigrade in our testing compared to observed numbers as high as 6-8 degrees C. differential in baseline tests.
The arrangement of FIG. 5 uses two airflow devices 501, 505. For purposes of easy identification, these are called the DAG Fan and the Shelf Fan, respectively. The DAG Fan 501 is attached close to the DAG 504 towards the outer end of the unit. This fan draws in warm ambient air and creates a parallel thinner airflow running alongside the default cold curtain of the unit. To facilitate this, the DAG Fan has air intake designed facing outside the unit. The horizontal location of the RAG 510 varies depending on the design of the refrigeration unit and hence the RAG may not always be vertically aligned with the DAG. To accommodate for these differences, the DAG Fan is mounted near the DAG with brackets that allow for adjusting the angle of the warm airflow during installation.
The Shelf Fan 505 is installed at the outer edge of the penultimate/last shelf 506. It draws and re-directs the cold air 508 descending from the DAG curtain 503 and combines with the colder air 507 coming from the back panel of the penultimate/last shelf. To facilitate this, the Shelf Fan has an air intake directed towards the top edge of the shelf it is installed on. This combined cold air is then directed towards the RAG entrance. The location of the RAG entrance varies depending on the design of the refrigeration unit. To accommodate these differences, the Shelf Fan is mounted to the shelf with brackets that allow for adjusting the angle of the resulting curtain during installation.
FIG. 6 shows the shape of the DAG curtain of a state of the art vertical open case refrigeration unit showing an illustrated version of infrared (IR) imaging without any of the embodiment of the current invention. The watershed effect is clearly seen as the cold curtain flares outwards as it descends vertically. This airflow shape and characteristic illustrated here is typical of current state of the art vertical open case refrigeration units.
FIG. 7 in stark contrast to FIG. 6, this illustrated version shows the shape of the DAG curtain as evinced by IR imaging with the embodiment of FIGS. 4 and 5. It is seen that the cold curtain shape is drastically altered. The curtain is clearly seen to be pulled inwards near the fourth shelf due to suction by the shelf fan. Overall the curtain descends more or less vertically without much dispersion/flaring, resulting in lower warm air infiltration and better refrigerator power performance. This airflow shape which is easily determined using thermal imaging, defines the objectives of this invention using the various devices and features described in this invention. By duplicating this shaping, the power savings principles described in this invention can be broadly applied.
FIG. 8 is a diagram of a side view of an illustrative retrofit DAG area airflow device housing 801 in accordance with an embodiment of the present disclosure attached near the DAG 802 of a state of the art vertical open-case refrigerator. In this iteration, the airflow device 801 is attached outwards of the DAG 802 by one of multiple commonly known methods including clips, strap, brackets, and bolts among others. Using one or multiple low power consumption cross flow fan impellers or blower wheels 803, ambient air 808 is pulled from the perforated/slotted intake 804 and forced out in a thin layer of air 805 parallel to the cold air curtain 806 to create containment. A flow conditioner such as honeycomb shaped material 807 enables the flow coming out of the airflow device to be laminar and coherent. The voltage of this unit may be increased or decreased to optimize the velocity released by the device, and thus the volume of air moved.
FIG. 9 is a diagram of a side view of an illustrative Shelf Fan airflow device in accordance with an embodiment of the present disclosure attached to the end of the shelf/shelves of a vertical open-case refrigerator. The airflow device 901 housing is attached to the end of the shelf/shelves 902 by one of multiple commonly known methods including clips, strap, brackets, and bolts among others. Using one or multiple low power consumption cross flow impeller fans or blower wheels 903, air 904 is pulled from the upper part of the shelf via a perforated/slotted intake 905 and forced out in a thin layer of air 906 across the bottom shelf to create containment. A flow conditioner such as a honeycomb shaped material 907 ensures the flow coming out of the airflow device is laminar and coherent. Since the shelf is being extended over the existing product price code, the airflow device can be mounted with its own product price code holder 908.
FIG. 10 is a diagram of a perspective view of an illustrative Shelf mounted airflow device 1001 in accordance with an embodiment of the present disclosure attached to the end of shelf of an open-case refrigerator. It shows the perforated air intake 1002 which captures air across the horizontal surface of the shelf and generates outflows 1003. The product price code attachment 1004 on the airflow device is shown.
FIG. 11 is a diagram of a perspective view of an illustrative shelf mounted airflow device in accordance with an embodiment of the present disclosure attached to the end of multiple shelves 1101 of a vertical open-case refrigerator. It shows that the airflow devices 1102 extend along the horizontal length of the front of each shelf. The thin airflow 1103 being released vertically along the horizontal length of the front of each shelf has a secondary effect of reducing the overflow out of the cavity from each shelf by creating separation between the interior of the shelf and the exterior of the shelf. This reduces the horizontal pressure on the air curtain. Additionally, as the airflow device intakes air at the bottom of each shelf, it also reduces the overflow by re-directing it downwards. The airflow devices of this invention have wiring 1104 to be attached to a power source which may be DC or AC and due to the low power usage required by these devices, may be powered by solar panels or batteries.
FIG. 12 shows the general design details of an airflow device used to generate airflow needed for this invention. The device consists of a housing 1201, single or multiple crossflow impellers 1202, an electrical motor 1203 that is preferably removable/replaceable, a flow conditioner such as a honeycomb shaped device 1204 which is also preferably removable and replaceable, and electrical connectors 1205. The airflow device assembly can be of a modular design facilitating quick assembly and replacement of individual components/modules. The housing has a perforated/slotted panel 1206 that acts as an air-intake while protecting the impeller/s 1202 from undue exposure or intrusion. The housing can have access panels that can be flipped open or removed to provide internal access for repair and maintenance. The housing has mounting features for snap-fit of impeller bearings such that the impellers can be individually put in or taken out with ease for replacement. The housing units containing the airflow devices can be designed to connect to another housing in parallel to run longer lengths of vertical open case refrigeration units which may be installed in an interconnected configuration. The housing units containing the airflow devices may also be connected vertically to simplify installation.
FIG. 13 shows the general design of the impellers used in the airflow device of FIG. 12. The impellers consist of prefabricated assembly 1301 made of metal, plastic, composites, or any combination thereof. The impeller has a male shaft 1302 at one end and a female hole 1303 at the other end. The impeller shaft rotates inside a bearing 1304 which provides for lubrication and support to the impellers. The impellers have flexible mating features on one end to couple it to the neighboring impeller while allowing for axial tilt during assembly/replacement.
FIG. 14 show the electrical motor. The electrical motor 1401 driving the impeller assembly 1402 is of brushed or brushless type, rated for 6-2 V, 0.1-0.25 A, and 2000-4000 rpm in one embodiment. The motor is coupled to the impeller assembly by a coupling 1403 housed inside a mounting feature in the housing. A motor mount integral to the housing allows for a snap-fit of the motor into the housing. As the motors have a known finite life of a few years, the motor mounting and coupling arrangement in one embodiment is designed for easy replacement of the motor. The motor is electrically connected to the housing via removable male-female connectors. The electrical connections consist of female sockets on either end of the housing. The sockets may be of any design and standard. Power is tapped from one of the sockets and supplied to the motor, while a wire running through the housing provides electricity at the other socket for connecting another airflow device. The fans are supplied with a 12v DC power via a wall-adapter, and have voltage adjustment devices inside the housing or on the power supply box for easy adjustment of the operating voltage, and hence the air-curtain speed.
FIG. 15 shows a flow conditioner 1501 which is preferably designed to be easily replaceable and can be made of plastic, metal, or other manmade or natural composite with specific geometric parameters. The purpose of the flow conditioner is to smoothen the flow coming out of the impeller(s) and provide uniform laminar flow regardless of where it is released. The flow conditioner may have arrays of channels 1502 of any shape and profile (including but not limited to square, rectangular, circular, hexagonal) in any pattern to achieve this. The dimensions of the flow conditioners are subject to change and may assume any value depending on the design of the refrigerator unit. The airflow device creates an air curtain that is approx. 10mm thick at exit and spans the length of the device. In this iteration, the average velocity of the air at the exit of the flow conditioner is typically between 0.2 m/s and 3 m/s, but may assume any value depending in the design of the refrigerator unit.
FIG. 16 shows the door/s used on the last shelf. The door/s consist of rectangular panels 1301 of a transparent material (glass, plastics or other composites) in a single or multiple split configuration. Although not necessary, the door/s may be attached to the shelf-fan or shelf via hinges 1302 or other similar flexible attachment at one end to allow for easy retraction and closure. A handle 1303 is installed on the other end to allow easy opening and closing of the doors. The doors may or may not have a slot 1304 running along most of its length to moderate flow. The size and location of the slot is not fixed and can assume any parameters depending upon the refrigeration unit's flow characteristics. The doors may or may not be installed depending on customer discretion and may also be of the sliding type.
FIG. 17A shows one embodiment of the present disclosure whereby the Shelf Fan is replaced with an air vent duct 1701 sitting between the edge of the shelf 1702 and the hinge 1703 of the bottom shelf door 1704. This air vent duct experiences some suction on account of the powerful suction at the RAG 1705 which is up to twice the velocity of the DAG airflow. In certain configurations, the RAG might provide enough suction at the air vent duct to make a Shelf Fan unnecessary. The duct runs along the entire width of the shelf, and the width of the duct is configurable based on the operating parameters of the particular unit the invention of this disclosure is retrofitted on. A flexible seal attached to the shelf doors 1704 would reduce cold air loss while strengthening the pull of the RAG from the air vent ducts.
FIG. 17B shows the concept of FIG. 17A in closer detail. The gap 1711 between the shelf 1712 and the hinge 1713 of the door 1714 forms an air vent duct, which experiences some suction on account of the powerful suction generated by the RAG. The width of the air vent duct 1711 is configurable based on the operating parameters of the particular unit the invention of this disclosure is retrofitted on.
FIG. 17C shows the concept of FIG. 17A in further detail. The gap 1721 between the shelf 1722 and the hinge 1723 of the door 1724 forms an air vent duct, which experiences some suction on account of the powerful suction generated by the RAG. The width of the air vent duct 1721 is configurable based on the operating parameters of the particular unit the invention of this disclosure is retrofitted on.
The housing containing the airflow devices can be universally retrofitted onto vertical open case refrigeration units by means of brackets, screws or other state of the art secure fastening method available. The mounting brackets may have provisions to set the angle of the devices of this inventions airflow to an optimal degree during installation to adapt to the design or configuration of the refrigeration unit and the characteristics of its airflow. Multiple fans can be connected in series such that several linear feet of refrigerated units can be powered by just one or multiple power supply(s). The individual units may be daisy-chained together using patch cables that electrically connect them to each other using the electrical jacks on the sides of the fans. The patch cables have male jacks on both ends that plug into the female sockets on the airflow device housing. Given the low power usage of the fans of this invention, (in most cases between 1-2 watts per device) there is a possibility to operate them using solar power arrays installed either inside or outside.
The retrofit solution presented in this invention includes the possibility of incorporating it into new production units by suitable design modifications. The key to the success of this invention is the characteristic shape and airflow signature that pulls and re-directs the cold airflow from the air curtain in an inward angle towards the last shelf which reduces the warm air infiltration at the RAG.
The DAG and Shelf Fan type devices of this invention with similar operating parameters can be made integral to the new vertical open case refrigerator unit with power supplied to the fan from within the unit's electrical supply.
Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.
Patent Application
20180084926
