U.S. patent application number 17/307310 was filed with the patent office on 2021-08-19 for coldwave appliance.
The applicant listed for this patent is IceColdNow, Inc.. Invention is credited to Benjamin J. Beck, Ryan J. Donovan, David Dussault, Douglas A. Marsden.
Application Number | 20210251418 17/307310 |
Document ID | / |
Family ID | 1000005557135 |
Filed Date | 2021-08-19 |
United States Patent
Application |
20210251418 |
Kind Code |
A1 |
Dussault; David ; et
al. |
August 19, 2021 |
COLDWAVE APPLIANCE
Abstract
A coffee appliance includes a powered cooling system integrated
with and matched to a hot coffee brewer, configured to cool
freshly-brewed coffee by thermal contact to chill a small batch of
fresh-brewed coffee in a cooled receiving vessel. The vessel has an
evaporator coil to ice the beverage. The cooling system is a robust
system, a phase change refrigerant compression-type system
employing a positive-displacement compressor, sized in relation to
its rate of thermal cooling and the temperature of the beverage and
the thermal mass and conductivity of the fluid-contacting assembly,
bringing hot coffee to an ice-cold temperature, 2-5.degree. C., on
demand and quickly. The fresh brewed, flash-cooled coffee has
undiluted and undegraded flavor. An integrated appliance includes a
coffee brewer and cooler in a single device, and a slide switch or
valve allows the user to select hot or iced coffee.
Inventors: |
Dussault; David; (Stoneham,
MA) ; Beck; Benjamin J.; (Boston, MA) ;
Marsden; Douglas A.; (Marblehead, MA) ; Donovan; Ryan
J.; (Watertown, MA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
IceColdNow, Inc. |
Braintree |
MA |
US |
|
|
Family ID: |
1000005557135 |
Appl. No.: |
17/307310 |
Filed: |
May 4, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15976966 |
May 11, 2018 |
11019957 |
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17307310 |
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PCT/US2016/047249 |
Aug 17, 2016 |
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15976966 |
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62254993 |
Nov 13, 2015 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A47J 31/44 20130101;
F25B 1/00 20130101; F25D 31/002 20130101; A47J 31/467 20130101 |
International
Class: |
A47J 31/44 20060101
A47J031/44; F25D 31/00 20060101 F25D031/00; F25B 1/00 20060101
F25B001/00; A47J 31/46 20060101 A47J031/46 |
Claims
1. An apparatus, comprising: a powered cooling assembly comprising
a compressor, a condenser, and an evaporator for compressing and
circulating a phase change refrigerant through a helical evaporator
coil; a cooling chamber configured and arranged to receive and
retain a batch of a beverage during a cooling interval, at least a
portion of the helical evaporator coil being positioned within the
cooling chamber; and a mixer disposed within the cooling chamber,
the mixer including at least one blade configured and arranged to
move within a central portion or around a perimeter of the helical
evaporator coil so as to drive the beverage radially against loops
of the helical evaporator coil.
2. The apparatus of claim 1, further comprising: a beverage brewer
configured to brew hot coffee or tea; and a control circuit
configured to control operation of the powered cooling assembly and
the beverage brewer so that the powered cooling assembly provides
selective cooling localized at the evaporator while the beverage
brewer is brewing the hot coffee or tea and dispensing the hot
coffee or tea into the cooling chamber.
3. The apparatus of claim 1, wherein the helical evaporator coil is
shaped as a double helix.
4. The apparatus of claim 1, wherein the at least one blade is
configured and arranged to move within the central portion of the
helical evaporator coil.
5. The apparatus of claim 4, wherein the at least one blade
comprises a plurality of vanes that extend vertically through at
least part of the central portion of the helical evaporator
coil.
6. The apparatus of claim 1, wherein the at least one blade is
configured and arranged to move around the perimeter of the helical
evaporator coil.
7. The apparatus of claim 6, wherein the at least one blade
comprises a plurality of vanes configured and arranged to move
circumferentially about helical evaporator coil.
8. The apparatus of claim 1, wherein a ratio of a heat transfer
surface area of the helical evaporator coil to a volume of the
cooling chamber is at least 0.02916 square feet per fluid
ounce.
9. The apparatus of claim 1, wherein the mixer is configured to
rotate the at least one blade at 290 or more revolutions per
minute.
10. The apparatus of claim 9, wherein the mixer is configured to
rotate the at least one blade at 440 or fewer revolutions per
minute.
11. The apparatus of claim 1, wherein a ratio of a heat transfer
surface area of the helical evaporator coil to a power consumed by
the compressor is at least 0.00096 square feet per Watt.
12. A method, comprising: operating a powered cooling assembly
comprising a compressor, a condenser and an evaporator for
compressing and circulating a phase change refrigerant through a
helical evaporator coil; introducing a beverage into a cooling
chamber in which at least a portion of the helical evaporator coil
is disposed; and operating a mixer disposed within the cooling
chamber so that at least one blade of the mixer moves within a
central portion or around a perimeter of the helical evaporator
coil so as to drive the beverage radially against loops of the
helical evaporator coil.
13. The method of claim 12, wherein the beverage comprises
freshly-brewed coffee or tea.
14. The method of claim 13, further comprising: controlling
operation of the powered cooling assembly and a beverage brewer so
that the powered cooling assembly provides selective cooling
localized at the evaporator while the beverage brewer is brewing
the coffee or tea and dispensing the coffee or tea into the cooling
chamber.
15. The method of claim 12, wherein the beverage comprises fruit
juice, an alcoholic cocktail, or wine.
16. The method of claim 12, wherein introducing the beverage into
the cooling chamber further comprises: retaining the beverage
within the cooling chamber during a cooling interval so that at
least a portion of the helical evaporator coil remains fully
immersed within the beverage during the cooling interval.
17. The method of claim 12, wherein the helical evaporator coil is
shaped as a double helix.
18. The method of claim 12, wherein operating the mixer comprises
moving the at least one blade within the central portion of the
helical evaporator coil.
19. The method of claim 18, wherein the at least one blade
comprises a plurality of vanes that extend vertically through at
least part of the central portion of the helical evaporator
coil.
20. The method of claim 12, wherein operating the mixer comprises
moving the at least one blade around the perimeter of the helical
evaporator coil.
21. The method of claim 20, wherein the at least one blade
comprises a plurality of vanes configured and arranged to move
circumferentially about helical evaporator coil.
22. The method of claim 12, wherein a ratio of a heat transfer
surface area of the helical evaporator coil to a volume of the
cooling chamber is at least 0.02916 square feet per fluid
ounce.
23. The method of claim 12, wherein operating the mixer comprises
rotating the at least one blade at 290 or more revolutions per
minute.
24. The method of claim 23, wherein operating the mixer comprises
rotating the at least one blade at 440 or fewer revolutions per
minute.
25. The method of claim 24, wherein a ratio of a heat transfer
surface area of the helical evaporator coil to a power consumed by
the compressor is at least 0.00096 square feet per Watt.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of and claims the benefit
under 35 U.S.C. .sctn. 120 to U.S. patent application Ser. No.
15/976,966, entitled COLDWAVE APPLIANCE, filed May 11, 2018, which
is a continuation of and claims the benefit under 35 U.S.C. .sctn.
120 and 35 U.S.C. .sctn. 365(c) to International Application
PCT/US2016/047249, entitled COLDWAVE APPLIANCE, with an
international filing date of Aug. 17, 2016, which claims the
benefit of U.S. Provisional Patent Application Ser. No. 62/254,993,
filed Nov. 13, 2015, the entire contents of each of which are
incorporated herein by reference for all purposes.
TECHNICAL FIELD
[0002] The present invention relates to devices and equipment for
preparing beverages. It also relates to refrigeration or cooling
equipment, and to an improved coffee brewing device.
SUMMARY OF THE INVENTION
[0003] The invention, referred to herein generally as the
"appliance", is a beverage device characterized by possessing a
powered cooling system and a contact-cooling portion having a
fluid-contacting part, such as an immersed cooling coil or a cooled
fluid-bounding wall or plate (a "cooling body" or "coil"), that is
cooled by the powered cooling system and is configured or
positioned to cool a hot beverage by thermal contact therewith. The
cooling system and body are matched to and operatively coordinated
with a hot beverage brewer, and the body is positioned to quickly
and effectively chill a small batch, such as an individual cup, or
in some embodiments a carafe, of freshly brewed or hot coffee that
is passed into or run through the vessel, removing the heat of
brewing, and bringing the beverage down to an icy temperature. The
appliance will be described with reference to a coffee brewer, such
as a `pod-type` or `k-cup` brewer or a filter-type drip brewer,
integrated as a single unit with the refrigerant/chiller assembly
and configured so that the user may select whether the beverage
output of the integrated brewer/chiller appliance is to be a cup of
freshly brewed hot coffee, or is to be a cup of freshly brewed and
flash-chilled iced coffee. The "iced" coffee thus produced is a
beverage of enhanced flavor, quickly and conveniently prepared
without extended refrigeration or use of ice, and has a taste that
is free of the dilution, and of the aging or oxidation, found in a
conventionally-prepared iced or refrigerator-cooled beverage.
[0004] The chiller portion is preferably chilled by a robust
powered cooling system such as a phase change refrigerant
compression-type system that employs a positive-displacement
compressor driven by an electric motor, and it is sized, in
relation to its required rate of thermal cooling and to the thermal
mass and conductivity of the beverage and the fluid-contacting
vessel assembly, to bring a cup, or a batch, of hot coffee to an
ice-cold temperature, for example, down to a temperature of about 2
to 5.degree. C. (35-40.degree. F.), on-demand and in a time period
that is compatible with the brew time, for example, of under about
two minutes, for the single cup embodiment set for a 4-, 6-, 8- or
10-ounce cup size. Preferably a selector control portion starts the
refrigerant compressor when the unit is turned ON, to pre-compress
a phase change refrigerant or pre-cool the cooling stage so that
the initial cup of brew is flash-cooled or cooled quite
quickly.
[0005] When embodied in an integrated or dual temperature
(selectable hot/cold) coffee device, the heating and brewing
portion or `first stage` may follow any conventional configuration,
for example may include a stage or portion substantially identical
to the popular "Mr. Coffee", "Keurig" or a common bar-style
Expresso brewing console. However the appliance further includes
operative components such that the freshly brewed hot coffee flows
in a short, or integrated or switched flow path, from the first,
brewing stage portion, through a second, chiller stage portion, to
an output to provide iced coffee with fresh-brewed flavor. In one
integrated brewer-chiller embodiment, the brewing and chilling
portions are arranged vertically, in a compact unit as upper- and
lower-flow-through stages, with the chiller constructed as an
evaporator coil suspended in a twist-on removable coffee-receiving
vessel or cup.
[0006] The invention may also be embodied in a counter-top,
chill-only appliance. The chill-only appliance may be configured
with a chiller cup mounted, for example on an arm extending out
from the appliance so that by moving the appliance the chiller cup
is positioned on the cup- or carafe-shelf or support of a common
domestic brewer. With such a construction, that is as a chill-only
appliance, the chiller may be simply user-actuated with an ON
switch, without specific control circuitry for coordination and
integration with the brewer. More generally, however the chill-only
appliance may be a counter-top chiller, a stand-alone beverage
cooler that receives a `cooling cup` or removably-positioned vessel
to contain hot coffee, and the cup or vessel is held or positioned
such that a refrigeration unit evaporator coil extends into the
cooling cup and is surrounded by a hot beverage that is to be
chilled. The cooling cup may attach by a twist-mount, bayonet or
magnetic coupling to the chiller head. In one embodiment a
plurality of moving vanes are positioned centrally within, or
around the perimeter of, the evaporator coil and are moved by a
motor or gear to deflect or stir the fluid in the vessel thereby
accelerating heat removal and assuring fast and uniform cooling of
the beverage while operating with a relatively modest refrigeration
unit and cooling elements or vessel of modest dimensions.
[0007] In either case, whether configured to catch the output of a
hot beverage brewer or configured as a free-standing chiller
appliance, the refrigeration portion of the chiller assembly has a
cooling capacity and thermal mass and cooling rate matched to a cup
or serving of hot coffee, or to the hot fluid output of the
conventional domestic or lunchroom coffee brewer, for example, to a
small, medium or large coffee cup size, or in some embodiments to a
small carafe batch size (e.g., 20-30 ounce size) of the brewer.
[0008] When intended as a general purpose counter-top chiller, an
embodiment may advantageously be constructed with refrigeration
components, such as a compressor and condenser assembly, mounted
below-the-counter, connected via flexible lines or rigid tubing, to
an above-counter beverage cooling head that includes an evaporator
coil which extends into a removably mountable cup or vessel in
which the beverage to be chilled is placed. Preferably the
counter-top chiller has a small footprint, and may be similar to a
soda fountain frappe machine; as such, the unit may also be used to
chill other beverages, such as fruit juice, alcoholic cocktails or
wine.
[0009] An embodiment of the integrated brewer-chiller appliance
includes a mechanical or an electrically operated valve for
selectively passing a brewed beverage stream to either a direct
output (e.g., to a cup for hot coffee), or to the chilling vessel.
The integrated appliance may further include control electronics
that coordinate the operation of the refrigerant components with
the heating/brewing cycle of the device, for example, to initially
compress the refrigerant, or to pre-cool the chiller vessel or
coil; or may include power control elements that vary and/or
selectively switch the refrigerant compression timing and fluid
flow regimens, allowing the device to flash cool at least an
initial cup of hot beverage, and/or to efficiently and effectively
cool a larger, e.g., carafe-sized batch of 24, 30 or 40 ounces of
hot coffee, either directly (if configured with a larger vessel or
refrigeration assembly), or by successively cooling several smaller
cup-sized flows at controlled times or intervals as the hot
beverage is being brewed. The control and switching elements may be
set such that, when initially switched ON, the refrigeration
components are powered; this assures that the compressor,
evaporator and condenser have attained an operation-ready state
when the flow of hot brewed coffee initially appears shortly
after.
[0010] The invention also contemplates embodiments wherein power
switching of the heater and of the compressor motor are effected
under selectable or automated control at offset intervals in such a
way as to limit the total power draw to below a desired peak
domestic appliance power consumption level, for example to under
1200, or under 900 or under 600 watts. Such control may be
programmed, and may additionally be responsive to thermal sensors
that detect the initial temperatures of the vessel, the vessel
contents, and/or the brew as it cools, while controlling flow
valves and powering the refrigerant assembly so as to achieve fast
and effective brewing and single-pass cooling without requiring
extended continuous or simultaneous operation of all the
power-using components, or incurring delays between the brewing and
the cooling intervals. In this embodiment, the thermal mass of the
cooling body or vessel, and the cooling rate or capacity of the
refrigerant system may be optimized to operate effectively by
partially pre-chilling the cooling body or vessel so as to brew and
flash cool an initial cup, while optionally cooling the subsequent
flow of coffee at a more moderate rate as it is brewed. With this
arrangement the appliance flash chills a cup of coffee, but lowers
the peak or duration of high electrical current draw by taking
advantage of the time delays inherent in refrigerant compression
and in thermal conduction profiles for contact cooling of the
fluid, and the characteristic delayed water heating and hot coffee
flow rate of a drip-brewing or k-cup coffee mechanism.
[0011] A presently preferred embodiment is a single cup
brewer-chiller device having a brewer portion which brews hot
coffee, a chiller portion to which the hot coffee may be
selectively channeled to be chilled, and a flow selector or valve
that either passes the hot coffee directly to an output port, or
selectively diverts the hot coffee into the chiller portion before
it passes to an output.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] These and other features of the invention will be understood
by reference to the figures below, taken together with the
description herein and the claims appended hereto, wherein:
[0013] FIG. 1 schematically illustrates functional elements and
organization of an embodiment of the Appliance and system flow for
selectively brewing, or for brewing and chilling, coffee;
[0014] FIG. 2 shows idealized states of a heat transfer refrigerant
on a temperature-entropy diagram of the beverage cooler;
[0015] FIGS. 3A, 3B, 3C and 3D show, by way of example, compressor,
condenser, throttle valve and evaporator elements useful in a
refrigerant assembly of the chiller appliance;
[0016] FIG. 4 shows measured cooling times achieved with several
mixer and condenser variations during testing and validation of
integrated chiller constructions;
[0017] FIGS. 5A and 5B show right- and left-front perspective views
of an integrated domestic brewer/chiller appliance;
[0018] FIGS. 6A, 6B and 6C show left-rear perspective views of the
appliance of FIG. 5 illustrating integration of refrigeration
elements into a coffee brewer;
[0019] FIGS. 7A and 7B illustrate operation of hot (FIG. 7A) and
cold (FIG. 7B) beverage selection mechanism; and
[0020] FIGS. 8A, 8B, 8C, and 8D further illustrate construction
details of a selectable chilling cup of the appliance of FIGS.
5-7.
DETAILED DESCRIPTION
[0021] FIG. 1 schematically illustrates functional elements and
organization of an embodiment of the present invention as an
appliance for "brewing" instant iced coffee. Operation of the
appliance involves brewing hot coffee, and chilling the beverage so
produced, wherein the chilling or refrigeration components of the
appliance are matched to the thermal load and brew path, being
sized, positioned and operated to quickly produce a cup of iced
coffee.
[0022] The upper portion of FIG. 1 shows the brewer stage of the
appliance, which is illustrated as following a conventional
domestic coffee brewer construction in which water is pumped from a
water reservoir 11 by a pump 13 into a heating chamber 12, and the
heating chamber is pressurized by an air pump 14 to force heated
water along a passage into a brewer stage 15, such as a pod- or
k-cup or filter cone coffee brewer, thus making hot, fresh-brewed
coffee. The hot coffee so produced passes from the bottom of the
brewer stage 15, either directly to a cup 16, or passes into a
cooling chamber 18 which cools the coffee to form an iced coffee
output. When the user has selected "hot" coffee, the brew may
follow a flow path centrally through the cooling chamber, without
contacting the cooling element. Such an arrangement is discussed
further below, and illustrated in FIGS. 5-8.
[0023] The lower portion of FIG. 1 schematically illustrates
arrangement of the refrigeration components of the appliance, and
their interface with the hot coffee brewer stage, and operation to
cool an evaporator coil. For producing iced coffee, the
refrigeration portion and the brewer portion of the appliance
overlap in the cooling chamber 18, in which coffee from the brewer
stage 15 is retained and contacts the evaporator coil during a
cooling interval. When a hot coffee output is selected, the cooling
chamber is simply bypassed. As shown in FIG. 1, the refrigeration
portion of the appliance may include a phase change refrigeration
compressor 21, which compresses and drives a refrigerant into a
condenser 22. The condenser may be cooled by a fan or an array of
fans to better dissipate the heat of condensation or compression,
denoted Qcond in the figure. From the condenser, the refrigerant
expands through a throttle valve 23 entering the evaporator coil 24
as a further-cooled fluid. The evaporator coil 24 is positioned in
the cooling chamber 18 to cool the hot coffee output of the brewer
by contact, absorbing heat, denoted Qevap, from the beverage. The
refrigerant then passes to an accumulator 25 before entering the
compressor 21 for the next compression cycle. The state of the
refrigeration fluid changes at the various points of the
refrigerant cycle in FIG. 1, starting from state 1 entering the
compressor, to a compressed but heated state 2 entering the
condenser, where heat is rejected to reach state 3, then expanding
and cooling as it passes through the throttle valve 23 and attains
state 4 entering the evaporator as a cooled heat exchange medium
for absorbing heat from the beverage before again returning to
state 1 in the accumulator ready for the next compression
cycle.
[0024] FIG. 2 shows the Temperature-entropy diagram corresponding
to states 1-4, illustrating the work performed in compressing the
refrigerant and in cooling the hot coffee.
[0025] By way of background and technical detail, applicant notes
that this application is based upon and related to the U.S.
Provisional Patent Application Ser. No. 62/254,993 filed in the
United States Patent Office on Nov. 13, 2015, cited supra and
incorporated by reference herein in its entirety. That provisional
filing described theory and operational characteristics of
prototype a domestic iced coffee appliances with a refrigerant
portion matched to a brewer so as to effectively make instant iced
coffee, and reported investigating the heat exchange effectiveness
and the actual or characteristic beverage cooling times of several
configurations of cooling elements as described therein, including
fluid cooling with a refrigerant compressor driving an evaporation
coil or a cooled plate; and the rate of cooling of the coffee as
affected by several different fluid mixing or stirring regimens.
The provisional patent application also suggested arrangements for
a free-standing chiller, for an integrated brewer-chiller, and for
improved implementations of an iced coffee appliance modeled on a
single-portion k-cup brewer or modeled on a pitcher-size drip
brewer. The reader is urged to consult the full text and disclosure
of that application, together with its figures, analytic models and
technical evaluations and alternative constructions, for
descriptions of technology for effective implementation of the
beverage cooler, and relevant factors and general considerations,
including theory, hardware, applications, and various test
procedures or results illustrating intended and desirable
embodiments and elucidation of technical factors defining the
nature and scope, capacity and operating characteristics achieved
by or achievable in embodiments of the invention.
[0026] As relevant hereto, applicant found that chilling times of
well under several minutes are achieved using a small (fractional
horsepower, under 500 watt) refrigeration compressor, and that
chilling is enhanced by providing a stirring or mixing mechanism in
the cooling chamber 18 to improve the rate of heat exchange and
uniformity of cooling, and avoid the formation of ice on the
evaporator coil. These thermal calculations and proof-of-principle
experiments were performed by adapting components with a modified
refrigeration cycle and a custom evaporator in thermal contact with
a receiving vessel or chamber sized for effective heat exchange
contact with a cup or batch of hot coffee. The experiments
identified and confirmed achievable target power usage of under
about a kilowatt for the combined heating and cooling requirements,
and achieving cooling times under two minutes, and suitable
dimensions and materials for components of a cup- or carafe-sized
on-demand coffee chiller. The size and scale are such that
embodiments of the chiller assembly may be integrated with the
switching, fluid heating, and fluid-channeling components of a
conventional coffee maker, and matched to the thermal load of the
coffee maker, to form an integral coffee brewer-chiller-dispenser
of enhanced performance that selectively provides hot coffee or
ice-cold coffee on demand in a counter-top appliance for domestic
use.
[0027] As such, the dimensions, power and thermal characteristics
fall in a low range and are engineered to collectively achieve fast
and effective cooling of the hot beverage. In addition, because the
Appliance includes a compressor powering a refrigerant-based
cooling cycle, in some embodiments it may also be run in a
continuous, or near continuous cooling mode (for example under
control to achieve or maintain a specific operating temperature)
and operated to successively cool an unlimited number of cups of
hot coffee, or more slowly cool a larger volume provided over a
longer time. Such an embodiment of the integrated Appliance is thus
adapted for large functions or events and the invention is not
limited to typical domestic or small office lunchroom
situations.
[0028] From a high level systems view, the basic function of the
device is to actively cool a small batch of a liquid rapidly,
without dilution, on demand. More specifically, for brewing a hot
beverage such as tea or coffee; the Appliance brews and then cools
the beverage from "near boiling" to "ice cold"; and cooling is
effected in a short time interval, comparable to the brew time of a
common single-serving domestic brewer. Illustratively, a coffee
cooling temperature drop of over 150.degree. F. is effected in an
operating time of under one or two minutes. By arranging the
cooling elements around the periphery of the cooling vessel, the
device may be configured so that when hot coffee is desired, a
manual selector allows the brew stream to simply pass centrally
through the cooling vessel, without loss of heat. Embodiments of
the integrated brew/chill Appliance may also be configured with a
sensor to sense the temperature of the cooled liquid and/or a
control circuit to control coolant cycles or to divert fluid flow
along separate `hot` or `chilled` paths to a receiving cup
accordingly. In some embodiments, controlling on the output
temperature, or both input and output temperatures, the Appliance
may be configured as a chiller only, and operated to chill other
beverages, such as alcohol-based cocktails, from a less extreme
initial temperature, e.g., from room- or wine-cellar temperature,
to a chilled or near freezing temperature.
[0029] The structure of the Appliance will be best understood
starting with a description of an illustrative embodiment as a
counter-top single serving coffee cooling appliance.
[0030] From a process flow perspective, a refrigeration cycle is
integrated with a batch cooling container or receiving vessel. The
refrigerant evaporator may comprise a helical coil sitting in the
vessel chamber, or tube embedded in a wall of the vessel, and is
positioned to remove heat from (i.e., to cool) the beverage in the
receiving vessel. The beverage is automatically channeled into the
container, or in some embodiments is poured (by hand), and is held
for the cooling duration, and is then exited, for example, via a
manually-operated spigot, via an automatically switched valve at
the bottom of the vessel, or by removing the vessel and decanting
the chilled beverage. The filling, cooling, and pour functions are
preferably coordinated by a logic board which actuates the
compressor/refrigeration components and the appropriate valves in
the fluid path. A temperature sensor may detect the desired thermal
endpoint (e.g., 35.degree. F.) and turn off the compressor, open an
output valve, and/or initiate a new fill/cool cycle.
[0031] As shown in the lower portion of FIG. 1, refrigeration
hardware may include a compressor, condenser, throttle valve, and
accumulator, examples of which are shown in FIGS. 3A, 3B, 3C and
3D. This hardware is similar to that of a standard small
refrigerator or a room air-conditioner construction, but may be
specifically scaled and adapted to the task of quickly cooling a
cup or batch of the hot beverage. An evaporator is preferably
provided as a custom coil fitted within the vessel, and may be a
helix, a double helix or other shape, or a plate cooled by
refrigerant tubes, incorporated with the beverage container for
effective cooling. A single helical coil positioned within a
cylindrical cooling vessel has been found to be effective.
Preferably a mixing mechanism is also provided to hasten heat
exchange between the hot beverage and the fluid-contacting surface
of the evaporator assembly in the cooling vessel. Mixing increases
the rate of heat transfer, especially at moderate or intermediate
temperatures.
[0032] Two mixing mechanisms have been found to perform well--blade
mixing (e.g., stirring) and bubble mixing. These may be implemented
with a rotary stirrer powered by a small drive extending down into
the fluid, or a diaphragm-type air pump, respectively which
provides a stream of air to churn the fluid. Blade mixing (e.g.,
with an assembly of moving vanes) is preferred to avoid possible
oxidation or flocculation effects that might occur from a bubble
mixer with some brews. The benefits of mixing include increasing
the heat transfer coefficient; decreasing the required surface area
of the evaporator element, cooling member or vessel; and avoiding
the formation of ice on the evaporator coil.
[0033] In a hot/cold coffee brewing Appliance, the coffee brew
portion of the appliance can employ the construction of an existing
brewer of the prior art; however the cooling technology, and the
integration of the coffee components with the cooling components,
is believed to be new and inventive. The discussion below for FIGS.
5-8 illustrates one basic integrated brewer/cooler device.
[0034] As a general beverage cooler, the Appliance may be
implemented as a stand-alone device rather than as a stage in a
brewing device, to enable the user to chill or process any
beverage. However, to integrate the technology into a single cup
brewer, preferentially with k-cups or other single-cup coffee
product, the Appliance is preferably configured with a rotary-type
refrigerant compressor to achieve a suitably narrow footprint, and
with a controller card and user control buttons, switches and fluid
valves to control the refrigeration components and fluid paths so
as to augment a conventional brewing device to provide the option
to serve hot coffee as usual or ice coffee that is "brewed hot,
served cold." Applicant has found that integrating the brewing and
cooling operations in this manner results in an iced coffee product
having exceptional flavor and freshness. A simple spring-loaded
valve in the brew head may provide dependable, single-slide user
operation without requiring complex electronics or control
circuitry.
[0035] Operation of the appliance will be understood with reference
to the thermal characteristics of its basic operation, involving a
refrigerant-based cooling module that cools a coffee-receiving
cooling vessel and sized for counter-top operation. FIG. 1
schematically illustrates functional elements of an embodiment of
the appliance and their system flow diagram, while FIG. 2 shows the
corresponding idealized states (at an instant in time) on a T-s
(temperature-entropy) diagram. As shown in the left side of FIG. 1,
refrigerant starts as a saturated vapor in state 1 and passes
through a compressor attaining a compressed state 2 or condenser
pressure at a higher temperature. In the condenser coil, the heat
of compression is rejected from the refrigerant with a heat flow
Q.sub.cond from the condenser into the surrounding air lowering the
temperature of the compressed refrigerant at state 3. A fan or
array of small fans directed at the condenser is provided in some
embodiments to provide air circulation and assure sufficient heat
transfer to avoid overheating of the condenser. From state 3 the
compressed refrigerant passes through a throttle valve, which
regulates flow of the cooled compressed refrigerant to a state 4
that then passes into the evaporator coil.
[0036] As shown in FIG. 1, the evaporator coil is placed in heat
exchange position with, or is positioned within, a beverage vessel
where it cools the beverage by absorbing a flow of heat Q.sub.evap
from the beverage into the refrigerant fluid, which expands or
evaporates and passes to the accumulator whence it again passes
into the compressor stage. Thus, from state 4 to 1, heat is
transferred in the evaporator from a hot beverage into the
refrigerant which then passes to another compression/refrigeration
cycle. The accumulator is positioned to prevent liquid from
entering the compressor. In FIG. 1, the beverage vessel is
illustrated schematically on the right side of the Figure,
corresponding to the output of a coffee brewer; in practice the
evaporator coil may be integrated with a coffee brewing device, and
the vessel may a bayonet-mount coffee-receiving cup that fits
around the evaporator and causes coffee to accumulate and rise up
and immerse the evaporator in hot coffee. The temperature-entropy
diagram of FIG. 2 illustrates states (1)-(4) described above. In
practice a suitable refrigeration assembly operating with a 300 to
500 watt motor has been found sufficient for effective operation of
the described domestic coffee chiller.
[0037] Hardware components or subsystems of the cooling portion may
be adapted from or similar to corresponding portions of common
consumer products such as a small room air conditioner or a
personal dormitory-style refrigerator. Typical components of this
type are illustrated in FIG. 3A-3D with discussion of some
attributes for technical consideration. The hardware elements
(compressor, condenser coil, evaporator coil) are sized and shaped
to fit the overall volume, and in certain embodiments designed to
constitute a pleasing design or stylized shape, of a counter-top
appliance. Thus, for example, the motor and compressor may form a
cylindrical functional unit about 10-12 cm in diameter by 25-30 cm
tall; the condenser coil may constitute a rectangular planar array
about 20 by 30 cm positioned on a rear face of the appliance and
cooled by a fan or an array of small fan units, and the evaporator
path may consist of a helical tube that is positioned for immersion
in a cup-shaped chamber or vessel that fits in a lower part of the
brew/drip path and receives the hot beverage.
[0038] FIG. 3A shows several compressor options, which may include
rotary (left image) and reciprocating (right image) compressor
mechanisms. Both are positive displacement compressors, which
operate efficiently for low refrigerant flow applications, and both
are commonly used in air conditioning and refrigeration
applications. The rotary compressor may include a liquid
accumulator, as shown on the far left in FIG. 3A, which assures
that liquid does not enter the compressor stage. From a performance
standpoint, both compressors are sufficient, and the choice of a
compressor for incorporation in the appliance may be driven by cost
and layout considerations. For bread boarding and the initial
thermal analysis, a rotary-type compressor from a 5,000 BTU air
conditioner manufactured by the LG corporation was employed, with a
reduced-size condenser and evaporator configured for effective
cooling and interfacing with a single-cup brewer or manually-poured
hot coffee.
[0039] The appliance is to occupy a countertop footprint similar to
that of a popular domestic coffee brewer, and may, like them,
include a programmable control chip which, may operate for setting
such features as initiation of the coffee brewing operation, as
well as operations unique to the appliance, such as initiation of a
cooling and/or a pre-cooling operation of the compressor, cooling
of the hot coffee, end of the cooling cycle, and, in some
embodiments, automatic passage of the cooled beverage to an output
port or receiving cup. The illustrated rotary compressor suggests a
size and overall shape similar to a domestic coffee brewer such as
a Keurig- or a CoffeeMate brewer, and this overall look was
selected for prototype construction.
[0040] Various options may be implemented for forming the condenser
portion of the refrigerant module. FIG. 3B illustrates several
possible condenser constructions. The left side shows a tube and
fin arrangement common to forced convection (fan driven) air
conditioners, and the right shows a natural convection type
commonly found, for example, in a low power or
continuously-operating refrigerator. It was decided to use a forced
convection type condenser coil to achieve a compact and inexpensive
counter-top appliance.
[0041] FIG. 3C shows several simple throttle valve constructions.
The left side shows a capillary tube, while the right side image
illustrates a pressure or flow reduction orifice. A variable area
valve was not considered for the sake of cost and minimal controls,
because the magnitude of the cooling task for the intended beverage
size and known starting temperature allows clear definition of a
fixed throttle valve. A capillary tube is chosen because it is less
sensitive to disturbances in the line and has been found to be
effective and commonly used in comparable cooling applications such
as air conditioners.
[0042] FIG. 3D illustrates several possible implementations of the
evaporator. The left side shows a bare helically-shaped tube for
immersion in the beverage. The right side shows a cold plate type
heat exchanger wherein intermediate material is used to provide a
flat beverage interface. The use of a cold plate construction would
increase cost and potentially introduce thermal resistance, in
particular relative to any air gaps (even small gaps on the order
of 0.001 in) that may exist between the refrigerant line and the
plate surface, while cleanability would be a potential trade-off
when using an elongated or a double-helical spiral evaporator coil.
However the components of brewed coffee, if they adhere to or build
up on the heat exchange contact surface, constitute at worst a
cosmetic, rather than a bacteriological, residue, so that
performance considerations of cooling efficacy make the bare coil
evaporator the first choice for implementation of the
appliance.
[0043] In embodiments of the beverage-cooling appliance, a mixing
mechanism is desirably also provided for the evaporator/cooling
vessel in order to enhance heat transfer between the evaporator and
the surrounding fluid, and to reduce the required surface area and
therefore size, and to prevent ice formation as the fluid contacts
the evaporator. Two mechanisms were considered: (1) a motor driven
blade, paddle, whisk or propeller for stirring the fluid, and (2)
an air compressor driven aerator/bubbler, which may be similar to
one used in a fish tank, or comparable in pressure to the aerator
of a latte machine.
[0044] Several refrigerants were considered, including R134a and
R410a. R134a is currently more commonly used in residential
applications, but the fluorocarbon mixture R410a appears to result
in better performance and, for environmental reasons, is likely to
be phased in as the dominant player in residential applications.
For these reasons, R410a is presently preferred for the
appliance.
[0045] Thermal modeling was performed for the process of cooling,
roughly contemplating cooling a 12 oz cup of coffee from
200.degree. F. down to 35.degree. F. in 2 minutes. The time
averaged evaporator heat transfer from the coffee to the
refrigerant is
Q . e .times. v .times. a .times. p = m .times. c p .times. .DELTA.
.times. T t .times. = > Q . e .times. v .times. a .times. p = (
1 .times. 2 1 .times. 6 .times. .times. lb .times. .times. m )
.times. ( 4 .times. 2 .times. 0 .times. 0 .times. J kg .times.
.times. K ) .times. ( 2 .times. 0 .times. 0 - 3 .times. 5 ) .times.
R ( 2 .times. min ) .times. ( 6 .times. 0 .times. s min ) .times. (
2.2 .times. lb .times. m k .times. g ) .times. ( 1 . 8 .times. R K
) = 1091 .times. W ##EQU00001##
[0046] Assuming a refrigeration coefficient of performance of 3,
the compressor power is given by
C .times. O .times. P = Q . e .times. v .times. a .times. p W . c
.times. o .times. m .times. p .times. = > W . c .times. o
.times. m .times. p = Q . e .times. v .times. a .times. p ( COP ) =
( 1 .times. 0 .times. 9 .times. 1 .times. W ) ( 3 ) = 3 .times. 6
.times. 4 .times. W ##EQU00002##
[0047] An energy balance gives the heat rejection in the condenser
from the refrigerant to the air
{dot over (Q)}.sub.cond={dot over (Q)}.sub.evap+{dot over
(W)}.sub.comp
=>{dot over (Q)}.sub.cond=(1091 W)+(364 W)=1455 W
[0048] In terms of the heat exchanger, the evaporator heat transfer
is given by
{dot over (Q)}.sub.evap=U.sub.evapA.sub.evap.DELTA.T.sub.evap
where U.sub.evap is the overall heat transfer coefficient,
A.sub.evap is the coffee/heat exchanger interface surface area, and
.DELTA.T.sub.evap is the temperature difference between the coffee
and the refrigerant. Assuming an overall heat transfer coefficient
of 1000 W/m2/K (forced convection, water) and a temperature
difference of 60 F, the heat transfer surface area is
A e .times. v .times. a .times. p = Q . e .times. v .times. a
.times. p U e .times. v .times. a .times. p .times. .DELTA. .times.
T e .times. v .times. a .times. p .times. .times. = > A e
.times. v .times. a .times. p = ( 1 .times. 0 .times. 9 .times. 1
.times. W ) .times. ( 3 . 2 .times. 8 .times. .times. ft m ) 2 ( 1
.times. 0 .times. 0 .times. 0 .times. W m 2 .times. K ) .times. ( 6
.times. 0 .times. R ) .times. ( K 1 . 8 .times. R ) = 0 . 3 .times.
5 .times. ft 2 ##EQU00003##
[0049] Similarly for the condenser, assuming 100 W/m/K (forced
convection, air) and a temperature difference of 20.degree. F.
A cond = Q . cond U cond .times. .DELTA. .times. T cond .times.
.times. = > A cond = ( 1 .times. 4 .times. 5 .times. 5 .times. W
) .times. ( 3 . 2 .times. 8 .times. ft m . ) 2 ( 1 .times. 0
.times. 0 .times. W m 2 .times. K ) .times. ( 2 .times. 0 .times. R
) .times. ( K 1.8 .times. R ) = 14 .times. ft 2 ##EQU00004##
[0050] The compressor and throttle valve can be sourced using
conventional refrigeration part specifications for the cooling load
above. Rough specs for the compressor are: a volume flowrate of 0.5
to 1.0 cfm and a pressure rise of 100 to 200 psi, depending on the
refrigerant type. Rough specs for the throttle valve are: a
capillary tube 0.040 to 0.050 in ID and a tube length of 2 to 3
feet. The performance calculations above are time averaged rough
estimates. Refined optimization is achieved with detailed analysis
and hardware testing; however, illustratively, a brief summary of
several test procedures is included herein.
[0051] For confirmation of modeling, a 5000 BTU/hr window air
conditioner (R410a) was deconstructed and substituted with a
suitably-sized evaporator heat exchanger. Performance levels were
reported in the aforesaid provisional patent filing, and a decision
was made to proceed with a helical evaporator coil for initial
product design. Testing further showed that mixing was effective to
prevent ice formation on the coil. Measurements were taken during a
number of mixing runs.
[0052] FIG. 4 shows a subset of the cooling run test results for
several prototype mixer and evaporator variations. The beverage
temperature change was roughly from 200 down to 40.degree. F. The
calculations showed that the condenser was oversized by a factor of
about 2.times. for the desired level of performance, and this was
subsequently verified in tests. A four blade mixer performed better
than an eight-bladed one, and diminishing returns were shown with
respect to speed, illustrating that only a moderate speed would be
needed. Interestingly, air mixing was found to be comparable to
blade mixing, so the choice between air vs blade mixing may be
considered open for final appliance product designs provided no
adverse taste or textures are introduced by aeration. A
paddle-wheel vane arrangement rotating around the coil periphery is
also deemed suitable. The prototyping tests, using compressor,
condenser, throttle valve, and accumulator hardware that are
standard refrigeration components, and an evaporator that, while a
custom coil, was a helix of relatively standard shape, fully
confirmed and enabled construction of integrated or free-standing
coffee coolers with on-demand batch cooling performance. The
helical evaporator coil in a cylindrical beverage cooling vessel
quickly and efficiently performed on-demand and fast cooling, while
the addition of any of several different mixing mechanisms--blade
mixing and bubble mixing--enhanced performance and prevented icing
of the coil, demonstrating an ability to operate continuously on
successive batch cooling tasks to handle cumulatively large tasks
such as event catering which may require individual serving on a
possibly repetitive basis. As noted above, other benefits of mixing
in addition to preventing ice formation on the coil include
increasing the heat transfer coefficient and decreasing the surface
area requirements, thus removing space and weight constraints on
the design and visual appearance of consoles or units embodying the
appliance.
[0053] FIGS. 5A and 5B illustrate the integrated brewer/icer of the
invention as embodied in a pod brewer 50, showing perspective views
from the front right (FIG. 5A) and front left (FIG. 5B). The
appliance has a control panel 52 which may include one or more
suitably wired button switches for ON, OFF, COLD or STANDBY, and
one or more LED status indicator lights to report a status such as
READY or BREWED. A user-filled water reservoir 53 occupies the left
side of the appliance, while the right side consists of a pod- or
filter-type brewer head 55 which notably includes a hot/cold
selector handle 56 at the level of the pod or filter (discussed
further in relation to FIGS. 7A and 7B infra, and a chiller cup or
vessel assembly 57 located vertically below the brew pod and above
the drip tray 60.
[0054] FIGS. 6A, 6B and 6C are perspective views from the back and
left of the integrated appliance 50 showing details of refrigerant
unit integration. The condenser coil assembly 62 is mounted on a
rear surface of the appliance 50 under a cover plate that serves to
channel cooling air provided by fans 63a, 63b (positioned in a fan
tray 64 below the condenser coil 62) through the cooling tower or
air duct 65 forming a rear portion of the body of the appliance.
This arrangement provides degree of thermal isolation between the
refrigerant heat dissipation elements and the cooling vessel while
improving the overall cooling capacity of the small refrigeration
assembly.
[0055] Returning to a front perspective view, FIGS. 7A and 7B
illustrate details of the brew basket assembly and operation with
the hot/cold selector handle 56 and cooling vessel 57 of FIG. 5A.
FIG. 7A shows the hot/cold selector in the HOT position, with the
corresponding position of the brew basket 71 and cooling vessel 57
shown in the lower portion of FIG. 7A. In this position, the outlet
passage 72 at the bottom of the brew basket 71 directly enters a
central outlet passage 57a of the vessel 57, allowing the hot
coffee to pass without contacting the evaporator coil 80 (FIGS.
8B-8D) that is positioned circumferentially around the central
region, and to fall straight through into a coffee cup resting on
the drip tray 60. FIG. 7B shows corresponding views when the
selector handle 56 is moved to the right into the COLD or ICED
COFFEE position. This motion moves the brew basket outlet passage
72 off center, so it is no longer aligned with the central hot
coffee outlet 57a, thus causing the hot brew to flow into and fill
the cooling vessel, contacting the evaporator coil and chilling the
coffee.
[0056] FIGS. 8A-8D illustrate further details of the cooling vessel
and evaporator coil for such operation. As shown, the evaporator
coil 80 fills a generally peripheral region, while the hot coffee
through passage 57a is located near the center and positioned to
align with the brew basket outlet 72 (FIG. 7A). As best seen in
FIG. 8D, the hot bypass passage 57a which may have a contact valve
at its top surface to close when not directly contacted by the brew
basket outlet 72, leads into an open bypass conduit 57b which keeps
the hot flow away from the nearby evaporator coil and allows the
hot brew to bypass the chilling cup and drop straight through to
the user's cup. However when the brew basket outlet 72 is not
aligned with the passage 57a, 57b the hot coffee falls on top plate
57c and runs off to the side or peripheral region, flowing down
over the evaporator coil so that the beverage is cooled. With this
arrangement, the helical evaporator coil may be positioned in a
narrow or closely fitting annular region between the central body
and the outer wall of the vessel to assure speed and efficiency of
cooling. As best seen in FIG. 8C, the evaporator assembly or the
vessel may further include a circumferentially mounted set of
oblique vanes 85. These may be driven by a motor or drive gear in a
paddle-wheel motion to deflect or drive the hot liquid radially
through the evaporator coil to enhance the rate of cooling of the
coffee pooled in the annular region of the chilling cup surrounding
the evaporator coil. Positioning the coil in an annular vessel
rather than an open cup assures a substantial degree of immersion
of the coil for effective heat transfer and cooling without
introducing localized ice bridging or thermal non-uniformity.
[0057] While FIGS. 7 and 8 illustrate a specific arrangement of
brew basket and chilling vessel passages for achieving bypass or
cooling operation without electrically-operated valves, it will be
appreciated that the illustrated manually-operated selector
mechanism is readily adaptable to various common brew baskets of
pod-, k-cup-, filter- or expresso-type coffee machines, and further
that such mechanical flow-selectors may instead be effected by
push-button, electrically operated valve, selector, and/or pump
mechanisms. Moreover mixing may, in various embodiments be
implemented by various paddle or whisk- or propeller-type stirring,
or flow deflection or recirculation mechanisms in the cooling
vessel to drive the coffee against the evaporator coil for fast
efficient heat transfer without icing up. It will be understood by
a person skilled in the art that the layout of elements may be
varied accordingly when the cooling mechanism is to be integrated
with, or manually positioned under a hot coffee brewer of different
overall shape, size or aspect.
[0058] Furthermore, architecture of the brew section may also be
varied within a broad range of constructions. Thus, for example,
while conventional k-cup or pod-type or other brewers commonly have
a top lid that lifts up slightly for insertion of the cup or pod,
or for placement of coffee and a drip filter, brew heads of the
present invention may be configured with a drawer mechanism that
pulls forward to allow insertion of the coffee charge, thereby
reducing the required vertical clearance for counter top operation.
In a drawer-type embodiment, the hot/cold coffee paths may also be
implemented differently, for example, may correspond to different
drawer positions, which operate to position the coffee charge over
different passages for direct output or diversion to the evaporator
cooler. It will also be appreciated that while the embodiment of
FIG. 6 generally places the heat rejection condenser on a broad
back surface of the appliance, and augments its efficiency by a
forced air channeling fan assembly, condenser positions at either
side are also feasible, and passive airflow can suffice when an
appliance is intended for occasional, single-cup or low volume
operation rather than broader household or cafe use. Other
variations may incorporate, start from or coordinate with different
existing brew mechanisms of the prior art, and may substitute steam
pressure for motorized pumping, electrically operated valves rather
than the described manual selector for directing either water or
brewed coffee along different paths, and chiller vessels
differently positioned in relation to the brew assembly.
[0059] The invention being thus disclosed and representative
embodiments described, further variations and modifications will
occur to those skilled in the art, and all such variations and
embodiments are considered to be encompassed in the invention, as
set forth herein and the claims appended hereto.
* * * * *