U.S. patent application number 10/714468 was filed with the patent office on 2005-05-19 for systems for regulating the temperature of a heating or cooling device using non-electric controllers and non-electric controllers therefor.
Invention is credited to Krempel, Benjamin J..
Application Number | 20050103040 10/714468 |
Document ID | / |
Family ID | 34573997 |
Filed Date | 2005-05-19 |
United States Patent
Application |
20050103040 |
Kind Code |
A1 |
Krempel, Benjamin J. |
May 19, 2005 |
Systems for regulating the temperature of a heating or cooling
device using non-electric controllers and non-electric controllers
therefor
Abstract
Described here are systems for regulating the temperature of a
heating or cooling device using a non-electric controller and
non-electric controllers therefor. In general, the systems
described here comprise a heating or cooling device and a
controller, or a heating or cooling device and a fluid circuit. The
heating or cooling device typically comprises a cold region and a
hot region, there being a temperature difference between the two,
and an input of constant energy. The controllers are configured to
be placed in thermal contact with at least a portion of the cold
region and at least a portion of the hot region, and are configured
to create a path for heat exchange between the portions of the
contacted hot and cold regions. The heat exchanged may be
controlled and the temperature of the system may be user
adjustable, or it may be automatically controlled.
Inventors: |
Krempel, Benjamin J.; (San
Francisco, CA) |
Correspondence
Address: |
MORRISON & FOERSTER LLP
755 PAGE MILL RD
PALO ALTO
CA
94304-1018
US
|
Family ID: |
34573997 |
Appl. No.: |
10/714468 |
Filed: |
November 14, 2003 |
Current U.S.
Class: |
62/383 ; 165/276;
165/277; 165/96 |
Current CPC
Class: |
G05D 23/08 20130101 |
Class at
Publication: |
062/383 ;
165/276; 165/277; 165/096 |
International
Class: |
F25D 003/12; F28F
027/00 |
Claims
What we claim is:
1. A system for regulating the temperature of a heating or cooling
device using a non-electric controller, comprising: a heating or
cooling device comprising a cold region, a hot region, and an input
of constant energy, there being a temperature difference between
the cold region and the hot region; and a controller comprising an
element of high thermal conductivity, the element configured to be
placed in thermal contact with at least a portion of the cold
region and at least a portion of the hot region, the element
further configured to create a path for heat exchange between the
portion of contacted hot region and the portion of contacted cold
region, whereby the heat exchange is controlled to regulate the
temperature of one of the regions, resulting in a controlled region
and a non-controlled region.
2. The system of claim 1 wherein the element comprises a metal
selected from the group consisting of aluminum, copper, silver, and
gold.
3. The system of claim 1 wherein the element has a thermal
conductivity of at least 50 (W)(m.sup.-1)(.degree. C..sup.-1).
4. The system of claim 1 further comprising a bimetal, the bimetal
being thermally insulated from the non-controlled region and
configured to be placed in thermal contact with at least a portion
of the controlled region.
5. The system of claim 4 wherein the heat exchange between the
non-controlled region and the controlled region is regulated, at
least in part, by thermal expansion of the bimetal.
6. The system of claim 1 wherein the temperature of the controlled
region is user adjustable.
7. The system of claim 5 wherein the temperature of the controlled
region is automatically controlled.
8. A system for regulating the temperature of a heating or cooling
device using a non-electric controller, comprising: a heating or
cooling device comprising a cold region, a hot region, and an input
of constant energy, there being a temperature difference between
the cold region and the hot region; and a fluid circuit, the fluid
circuit comprising a channel with a fluid therethrough, the fluid
circuit configured to be placed in thermal contact with at least a
portion of the cold region and at least a portion of the hot
region, the fluid circuit further configured to create a path for
heat exchange between the portion of contacted hot region and the
portion of contacted cold region, whereby the heat exchange is
regulated to control the temperature of one of the regions,
resulting in a controlled region and a non-controlled region.
9. The system of claim 8 further comprising an adjustable valve for
controlling the path and flow rate of the fluid in the fluid
circuit.
10. The system of claim 8 further comprising an element having a
high thermal conductivity, the element configured to be placed in
thermal contact with the fluid circuit and one of the regions.
11. The system of claim 10 wherein the element comprises a metal
selected from the group consisting of aluminum, copper, silver, and
gold.
12. The system of claim 11 wherein the element has a thermal
conductivity of at least 50 (W)(m.sup.-1)(.degree. C..sup.-1).
13. The system of either of claims 8 or 10 further comprising a
bimetal, the bimetal being thermally insulated from the
non-controlled region and configured to be placed in thermal
contact with at least a portion of the controlled region.
14. The system of claim 13 wherein the heat exchange between the
non-controlled region and the controlled region is regulated, at
least in part, by thermal expansion of the bimetal.
15. The system of claim 8 wherein the temperature of the controlled
region is user adjustable.
16. The system of claim 13 wherein the temperature of the
controlled region is automatically controlled.
17. A system for regulating the temperature of a heating or cooling
device using a non-electric controller, comprising: a heating or
cooling device comprising a cold region, a hot region, and an input
of constant energy, there being a temperature difference between
the cold region and the hot region, and an airflow over them; and a
controller configured to alter the airflow rate over one of the
regions, whereby heat is exchanged to the environment in a
controlled manner to regulate the temperature of one of the
regions, resulting in a controlled region and a non-controlled
region.
18. The system of claim 17 further comprising a bimetal, the
bimetal being thermally insulated from the non-controlled region
and configured to be placed in thermal contact with at least a
portion of the controlled region
19. The system of claim 18 wherein the heat exchange between one of
the regions and the environment is controlled, at least in part, by
the thermal expansion of the bimetal.
20. They system of claim 19 wherein the temperature of the
controlled region is user adjustable.
21. A controller for regulating the temperature of a heating or
cooling device comprising: an element of high thermal conductivity,
the element configured to be placed in thermal contact with at
least a portion of a cold region of a heating or cooling device and
at least a portion of a hot region of a heating or cooling device,
the element further configured to create a path for heat exchange
between the portion of contacted hot region and the portion of
contacted cold region, whereby the heat exchange is controlled to
regulate the temperature of one of the regions, resulting in a
controlled region and a non-controlled region.
22. A fluid circuit for regulating the temperature of a heating or
cooling device comprising: a channel with a fluid therethrough, the
fluid circuit configured to be placed in thermal contact with at
least a portion of a cold region of a heating or cooling device and
at least a portion of a hot region of a heating or cooling device,
the fluid circuit further configured to create a path for heat
exchange between the portion of contacted hot region and the
portion of contacted cold region, whereby the heat exchange is
regulated to control the temperature of one of the regions,
resulting in a controlled region and a non-controlled region.
23. A controller for regulating the temperature of a heating or
cooling device wherein the controller is configured to alter the
airflow rate over a cold or hot region of a heating or cooling
device, whereby heat is exchanged to the environment in a
controlled manner to regulate the temperature of one of the cold or
hot regions, resulting in a controlled region and a non-controlled
region.
Description
BACKGROUND
[0001] It is often desirable to regulate the temperature of a
heating or cooling system. In this respect, controllers and control
systems are commonly used. These controllers and controls systems
help obtain, maintain, or change the temperature of the system.
Typically, controllers for heating or cooling systems are electric
in nature. These controllers are termed "electric" because they
function by regulating or modulating some electrical aspect of the
system, such as the system voltage, or the system power.
[0002] Thermostatic and steady-state electric controllers are among
the most common types of controllers for thermoelectric module
("TEM") based heating or cooling systems. Compared to compressor
driven refrigerators and resistive electric heaters, TEM based
systems typically operate at higher currents and on DC rather than
AC current. This has heretofore made traditional low-cost
controllers such as bimetal thermostats, unacceptable for use as
controllers for TEM based systems.
[0003] A thermostatic controller operates by maintaining a
temperature between two temperature limits. That is, a thermostatic
controller operates to control the temperature of a cooling system
by turning on or off cooling power when certain temperatures are
reached. For example, when the temperature of the system gets too
high, the controller turns on the cooling power to cool the system
down. When the lower temperature limit is reached, the cooling
power is turned off, and this cycle repeats itself to maintain the
system temperature within the upper and lower temperature limits.
The difference between the two set temperature limits is known as
the system's hysteresis.
[0004] A steady-state controller, on the other hand, is designed to
continually hold a set-point temperature with very little
variation. It is often the controller of choice when a system
temperature must be maintained with a high degree of certainty.
When the steady-state temperature is disrupted, (e.g., by a change
in ambient conditions) the controller acts to quickly bring the
temperature back to the steady-state temperature. Steady-state
control is often achieved with some variant of a proportional
controller.
[0005] Electromechanical devices such as bimetal snap disks or
relays are typically not used to control the temperature of TEM
based systems. This is because direct current switching leads to
contact pitting and premature wear from arcing, and because the
number of switching cycles of the mechanical component limits the
life of the device. In addition, the hysteresis of an
electromechanical system is often set undesirably large in order to
avoid premature device failure. Furthermore, snap disks are
difficult to incorporate into an adjustable set-point device. This
has lead to an almost uniform adoption of electric controllers as
necessary components of TEM based systems. Some devices employ an
electric controller plus additional structural components for
altering between heating and cooling modes. The selection of a
suitable controller is often one of the biggest considerations when
designing heating or cooling systems, especially since electrical
controllers have proven to be very costly.
[0006] Accordingly, improved controllers and control systems
capable of regulating the temperature of TEM based heating or
cooling systems would be desirable.
SUMMARY
[0007] Described here are systems for regulating the temperature of
a heating or cooling device using non-electric controllers and
non-electric controllers therefor. For example, one described
system comprises a heating or cooling device and a controller. The
heating or cooling device comprises a cold region, a hot region,
and an input of constant energy, there being a temperature
difference between the cold and hot region. The controller
comprises an element of high thermal conductivity that is
configured to be placed in thermal contact with at least a portion
of the cold region and at least a portion of the hot region. The
element is further configured to create a path for heat exchange
between the portion of the contacted hot region, and the portion of
the contacted cold region. In this way, heat exchange may be
controlled to regulate the temperature of one of the regions,
resulting in a controlled region and a non-controlled region. The
element may comprise a metal, or a mixture of metals. Suitable
metals, for example, include aluminum, copper, silver, and gold. In
some variations, the element has a thermal conductivity of at least
50 (W)(m.sup.-1)(.degree. C..sup.-1).
[0008] The system could further comprise a bimetal, which is
thermally insulated from the non-controlled region and configured
to be placed in thermal contact with at least a portion of the
controlled region. In some variations, the heat exchange between
the non-controlled region and the controlled region is regulated,
at least in part, by thermal expansion of the bimetal. The
temperature of the system may be user adjustable, or it may be
automatically controlled.
[0009] Another system described herein comprises a heating or
cooling device and a fluid circuit. The heating or cooling device
comprises a cold region, a hot region, and an input of constant
energy, there being a temperature difference between the cold and
hot region. The fluid circuit comprises a channel with a fluid
therethrough, which is configured to be placed in thermal contact
with at least a portion of the cold region and at least a portion
of the hot region. The fluid circuit is further configured to
create a path for heat exchange between the portion of contacted
hot region and the portion of contacted cold region. In this way,
the heat exchange may be regulated to control the temperature of
one of the regions, resulting in a controlled region and a
non-controlled region.
[0010] The system may further comprise an adjustable valve for
controlling the path and flow rate of the fluid in the fluid
circuit. The system may also comprise an element having a high
thermal conductivity, which is configured to be placed in thermal
contact with the fluid circuit and one of the regions. The element
may comprise a metal, such as aluminum, copper, silver, or gold, or
may comprise mixtures of metals. In some variations, the element
has a thermal conductivity of at least 50 (W)(m.sup.-1)(.degree.
C..sup.-1). The system may further comprise a bimetal, which is
thermally insulated from the non-controlled region and configured
to be placed in thermal contact with at least a portion of the
controlled region. In some variations, the heat exchange between
the non-controlled region and the controlled region is regulated,
at least in part, by thermal expansion of the bimetal. The
temperature of the system may be user adjustable, or it may be
automatically controlled.
[0011] Yet another system described herein comprises a heating or
cooling device and a controller configured to alter an airflow
rate. The heating or cooling device comprises a cold region, a hot
region, and an input of constant energy. In this system, there is a
temperature difference between the cold and the hot region, and
airflow over them. The controller is configured to alter the
airflow rate over one of the regions. In this way, heat is
exchanged to the environment in a controlled manner to regulate the
temperature of one of the regions, resulting in a controlled region
and a non-controlled region.
[0012] This system may comprise a bimetal, which is thermally
insulated from the non-controlled region and configured to be
placed in thermal contact with at least a portion of the controlled
region. In some variations, heat exchange between one of the
regions and the environment is controlled, at least in part, by
thermal expansion of the bimetal. The temperature of the system may
be user adjustable, or it may be automatically controlled.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIGS. 1A-1C are illustrative depictions of systems for
regulating the temperature of a heating or cooling device where
solids are used to transfer heat.
[0014] FIGS. 2A-2C are illustrative depictions of systems for
regulating the temperature of a refrigeration device where liquids
are used to transfer heat.
[0015] FIGS. 3A-3C are illustrative depictions of systems for
regulating the temperature of a refrigeration device where both
solids and liquids are used to transfer heat.
[0016] FIGS. 4A-4C are illustrative depictions of systems for
regulating the temperature of a refrigeration device where both
solids and gases are used to transfer heat.
DETAILED DESCRPITION
[0017] Described here are systems for regulating the temperature of
a heating or cooling device using a non-electric controller and
non-electric controllers therefor. In general, the systems
described here comprise a heating or cooling device and a
controller, or a heating or cooling device and a fluid circuit. The
heating or cooling device typically comprises a cold region and a
hot region, there being a temperature difference between the two,
and an input of constant energy. The controller is configured to be
placed in thermal contact with at least a portion of the cold
region and at least a portion of the hot region, and is configured
to create a path for heat exchange between the portions of the
contacted hot and cold regions. In this way, heat exchange may be
controlled to regulate the temperature of the hot or cold region,
thereby resulting in a controlled region and a non-controlled
region.
[0018] The non-electric controllers useful with the described
systems may provide several advantages over the traditional
electric controllers typically employed with TEM based systems. For
example, the non-electric controllers described herein may be
capable of reducing electromagnetic interference when compared with
pulse-width modulation controllers. In addition, the non-electric
controllers may be capable of switching between cooling and heating
systems without reversing the polarity across the TEM. This in turn
may help to reduce the thermal cycling of the TEM and consequently,
may result in a higher reliability of the TEM over time. In
addition, the non-electric controllers described herein may be made
at a low cost without sacrificing the high performance typically
achieved with traditional electric controllers. In this way, the
controllers and systems for regulating temperature described herein
may be especially useful in cold therapy devices, as well as small
or portable refrigerators.
[0019] The controllers may be configured in any number of ways. For
example, they may employ liquids, gases, solids, or some
combination thereof, in order to aid in the transferring of heat.
In addition, the systems described herein may be useful as heaters
or as coolers. The difference between the heating and cooling
system is typically dependent upon, for example, the configuration
of the output side, and the region the non-electric controller
references in regulating the system temperature. Turning now to the
drawings, wherein like numerals indicate like elements throughout
the views, there is shown in FIGS. 1A-1C systems in which the hot
and cold regions have a solid, highly conductive junction, which is
used in transferring heat.
[0020] As shown in FIG. 1A, the system (100) comprises a
refrigeration device (102), and a controller (110). The
refrigeration device (102) comprises a hot region (104), a cold
region (106), and a TEM (108). It should be noted that while a TEM
is depicted throughout the figures, a TEM is not required. Indeed,
any suitable heat pump may be used with the systems described
herein. The controller comprises an element (112) having a high
thermal conductivity, which is configured to be placed in thermal
contact with at least a portion of the cold region (106) and at
least a portion of the hot region (104).
[0021] The hot region (104) may be made from any number of suitable
materials. For example, it can be made from a highly conductive
material, capable of dissipating heat, such as certain metals.
Suitable metals include, but are not limited to, aluminum, copper,
and mixtures thereof. The cold region (106) may similarly be made
from any number of suitable materials, for example, it may be made
of a highly conductive material, or made of a material capable of
functioning as a heat sink. Suitable metals include, but are not
limited to, aluminum, copper, and mixtures thereof. The hot and
cold regions may be of any suitable dimension, which is typically
dependent on the overall system size. In this way, the heat pumped
through the system may be transferred. The hot region (104) and
cold region (106) may also be configured to be reversible in some
capacity.
[0022] The element (112) depicted in FIG. 1A may take on any number
of configurations. In FIG. 1A, element (112) is shown as a manual
slide, or a block. However, element (112) need not take such form.
Indeed, any geometry permitting element (112) to be placed in
thermal contact with at least a portion of the hot region (104) and
at least a portion of the cold region (106) may be suitable.
[0023] Similarly, the element (112) may be made from any suitable
material. For example, the element may comprise a metal or a
mixture of metals. Suitable metals include aluminum, copper,
silver, gold, and the like. In some variations it may be desirable
that the element has a thermal conductivity of at least
50(W)(m.sup.-1)(.degree. C..sup.-1). The element (112) is
configured to be placed in thermal contact with at least a portion
of the cold region (106) and at least a portion of the hot region
(104) and to create a path for heat exchange between the portion of
contacted hot region (105) and the portion of contacted cold region
(107). In this way, element (112) creates a path for heat to flow
from the hot region (104) to the cold region (106) in order to
regulate the system temperature. Typically, the extent of heat
transfer between the two regions is dependent upon the extent of
surface area contact between element (112) and the hot (104) and
cold (106) regions. Accordingly, element (112) is often movable, so
that it can be moved or positioned to have greater or lesser
surface area contact with the hot (104) and cold (106) regions.
[0024] For example, when element (112) is moved into contact with
the hot region (104) and the cold region (106), the thermal
resistance of the system is decreased, allowing heat to flow from
the hot region to the cold region. The greater the contact between
the hot and cold regions and the element, the greater the heat that
gets transferred. The system (100) shown in FIG. 1A is user
adjustable. That is, a user may turn the adjustment control knob
(114) to adjust the position of element (112). In this way, the
system output may be made hotter or colder and the temperature of
the system regulated. It should be noted, however, that while the
system of FIG. 1A is capable of providing for a range of
temperatures, the range will typically be relative to the ambient
temperature or the temperature of the surrounding environment.
Therefore, the user would be able, for example, to make the system
temperature cold, colder, or coldest in the case of a cooler, and
hot, hotter, or hottest in the case of a heater.
[0025] FIG. 1B shows another system (116) where the temperature is
automatically controlled using a bimetal. As shown in FIG. 1B,
system (116) comprises a refrigeration device (118) and a
controller (126). The refrigeration device comprises a hot region
(120), a cold region (122), and a TEM (125). Again, while a TEM
(125) is depicted, any suitable heat pump may be used. The
controller (126) comprises an element (128), a bimetal securing
screw (130), a bimetal strip (132), and a bimetal adjuster
(134).
[0026] The bimetal strip (132) may be made out of any suitable
bimetal, i.e., any material comprising two different metals having
different coefficients of thermal expansion, which are bonded
together. The bimetal industry is a mature one having certain
standards (e.g., ANSI standard, etc.), and any of these known
industry bimetals, for example, are acceptable. The bimetal
threaded adjuster may be made of any material, for example,
stainless steel. However, in some instances it may be desirable for
the threaded adjuster to be made of an engineering polymer, or some
other thermal insulator, so as not to alter the bimetal
temperature.
[0027] The bimetal strip (132) is configured to connect to, or
otherwise configured to facilitate movement of, element (126). In
this way, expansion or contraction of bimetal strip (132) regulates
the position of element (126) relative to the hot (120) and cold
regions (122) in order to control the system temperature. That is,
the bimetal strip (132) typically deforms at a measurable rate, as
a function of its temperature throughout its effective range, due
to the thermal expansion of the bimetal and the chosen bimetal
properties. Typically, the bimetal strip (132) is thermally
insulated from the non-controlled region and is configured to be
placed in thermal contact with at least a portion of the controlled
region.
[0028] As noted above, the system to be regulated may be either a
heating or cooling system. Illustratively depicted in FIG. 1B is a
cooling system. In operation, for example, as the temperature of
the cold region (112) changes, the bimetal expands or contracts to
move element (128) in towards TEM (124). The contact of element
(128) with hot region (120) and cold region (122) creates a path
for heat exchange, allowing heat to transfer from hot region (120)
to cold region (122). In this way, bimetal strip (132) helps to
control and regulate the temperature of the system. That is, unlike
system (100) depicted in FIG. 1A, whose temperature regulation is
dependent upon the ambient temperature, the system (116) of FIG. 1B
has a fixed temperature which is controlled in a self-regulating,
or automatic fashion.
[0029] Another system (136) is depicted in FIG. 1C. The system of
FIG. 1C is similar to system (116) depicted in FIG. 1B, but system
(136) has a user adjustment knob (156). The adjustment knob (156)
allows a user to adjust the temperature within a set range of
temperatures. The allowable temperature range is typically dictated
by the selection of the bimetal material used to make bimetal strip
(152).
[0030] The adjustment knob (156) of FIG. 1C, like the adjustment
knob (114) of FIG. 1A, and the other knobs depicted throughout the
figures, may be any acceptable knob, for example, the type of knob
most commonly used as a radio dial. Indeed, structurally, the knobs
may of any configuration capable of changing the position of
element (148) with respect to bimetal strip (152). Similarly,
bimetal securing screws (130) and (150) may be made out of any
material, for example, stainless steel or various engineering
polymers. However, selection of metallic bimetal securing screws
may help insure that the temperature of the bimetal is close to the
reference temperature.
[0031] FIGS. 2A-2C depict systems having a fluid circuit, where the
hot and cold region junction employs a liquid to transfer heat.
FIG. 2A shows a user adjustable system (200). As shown there, the
system (200) comprises a refrigeration device (202) and a fluid
circuit. The refrigeration device comprises a hot region (204)
having a fluid channel (206) passing therethrough, a cold region
(208) having a fluid channel (210) passing therethrough, and a TEM
(214). The system (200) shown in FIG. 2A also has a check valve
(216) and a check valve spring (218).
[0032] The hot and cold regions are of the same type as those
described in FIGS. 1A-C, and accordingly, as noted above, can be
made of any suitable material and be of any suitable dimension. For
example, the hot and cold regions may be made of a thermally
conductive material, such as a metal. The fluid channels traversing
through the hot and cold regions may carry any number of suitable
fluids. In some variations, water is used in the fluid circuit. The
check valve may be any check valve useful in preventing the fluids
from mixing when it is not desirable for them to do so. Similarly,
the check valve should permit the fluids to mix when it is
desirable for them to do so.
[0033] One way that system (200) may be operated, is illustratively
depicted in FIG. 2A. When the control valve (220) is completely
closed, the fluid flows only through the hot region channel (206).
That is, the fluid enters from input channel (203), flows through
hot region channel (206), and then flows out through output channel
(205). As noted above, the system may be used as a heater or a
cooler, depending on the nature of its configuration. For example,
the system may be configured such that input channel (203) and
output channel (205) are connected to a pump, and optionally a
radiator, and the system be made suitable as a cooler. In this
variation, the cold region (208) could be the output side, and may
be used, for example, like a cold plate. Conversely, if it were
desirable to have hot region (206) as the output side, then system
(200) could be configured as a heater. In this variation, for
example, the flow out of the output side (205) could go to a
heating pad, or other heating or warming device.
[0034] Typically, the check valve (216) is actuated by pressure
within system rather than by gravity. For example, if control valve
(220) is completely closed, then the cold region (208) is typically
at a lower pressure than the hot region (204). This pressure
difference causes the check valve to prevent the fluid from mixing.
Similarly, when the control valve (220) is opened, the pressure
within the system equalizes and the check valve ball moves into
spring (218) compressing it, creating a space. The space created by
the spring compression allows the fluid to pass through, and
therefore, mix together. That is, when check valve (216) is
partially open, fluid flows in from input channel (203) and flows
both through hot region channel (206) and cold region channel
(210).
[0035] In this way, a user can regulate the temperature of the
system by adjusting the control valve (220). For example, a user
can heat up a system that is too cold, or the user can cool down a
system that is too hot. However, without more components, the
system depicted in FIG. 2A, is typically not self regulating.
Instead, the user would have only relative temperature control
(e.g., cold, colder, coldest in the case of a cooler, and hot,
hotter, hottest in the case of a heater).
[0036] FIG. 2B illustrates a system (222) having a fixed
temperature set point. Thus, unlike the system (200) of FIG. 2A
where temperature is controlled in a relative fashion, the
temperature of system in FIG. 2B, is regulated in an absolute
fashion. Turning now to FIG. 2B, there is a refrigeration device
(224), and a bimetal (240). The refrigeration device comprises a
hot region (226) having a fluid circuit (228) passing therethrough,
a cold region (230) having a fluid circuit (232) passing
therethrough, and a TEM (234). Also shown is check valve (236) and
check valve spring (238).
[0037] The system of FIG. 2B is similar in operation to the system
of FIG. 2A, however, in FIG. 2B, the temperature of the system is
regulated, at least in part, by thermal expansion of bimetal (240).
Typically, the bimetal (240) is thermally insulated from the
non-controlled region and configured to be placed in thermal
contact with at least a portion of the controlled region. Thus, as
shown in FIG. 2B, if it is desirable, to regulate the temperature
of the cold region (230) the bimetal (240) would be placed in
thermal contact with cold region (230) to use it as a reference
temperature. Similarly, the system may be modified so as to
regulate the temperature of hot region (226) by placing the bimetal
(240) in thermal contact with hot region (226) so as to use the hot
region (226) as a reference temperature.
[0038] Another system is illustrated in FIG. 2C. Shown there is a
system involving aspects of both FIG. 2A and FIG. 2B. That is, the
system (242) provides a fixed temperature with an adjustable range.
As shown in FIG. 2C, system (242) comprises a refrigeration device
(244) and a bimetal (260). The refrigeration device comprises a hot
region (246) having a fluid circuit (248) therethrough, a cold
region (250) having a fluid circuit (252) therethrough, and a TEM
(254). Also shown in FIG. 2C are a check valve (256), a check valve
spring (258), and a user adjustment knob (262).
[0039] In operation, the system (242) of FIG. 2C functions in a
fashion similar to that of systems (222) and (200). That is, the
check valve (256) is actuated by the pressure within the system and
compression into check valve spring (258) creates a space for fluid
to flow therethrough. The system (242) has a user adjustment knob
(262) which allows the user to adjust the temperature of the
system. The range of temperatures for which the user can achieve is
set by the bimetal (260). Therefore, while the system is user
adjustable, it is adjustable within a set range of temperatures,
typically dictated by the selection of bimetal (260).
[0040] FIGS. 3A-3C illustrate other systems for regulating the
temperature of a refrigeration device. As shown therein, the hot
and cold region junctions are regulated using both solids and
liquids. For example, shown in FIG. 3A is a system (300) comprising
a refrigeration device (302), a hot region (304) having a fluid
channel (306) therethrough, a cold region (308), and an element
having a high thermal conductivity (312). Also shown therein is a
user adjustment knob (316) and a mechanism (314) to connect the
element (312) to the user adjustment knob (316), here, shown as a
rod.
[0041] As noted above, the systems described in FIGS. 3A-3C may be
configured to operate as heaters or coolers, for example, by
selecting the system output region or by selecting the reference
region. That is, the output may be configured to be on the side of
either the cold or hot region of the system, depending on what is
desirable. For example, if it is desirable to have the system
output on the cold region, then the system can operate as a cooler.
In this variation, the temperature of the cold region could be
regulated, and the cold region could function as a cold plate, or
the like. This may be useful, for example, during laboratory
experimentation, where it may be desirable to have a cold plate to
regulate the temperature of certain samples. In this variation, the
input (303) and output (305) channels of hot region (304) could be
connected to a pump, and an optional radiator or fan to remove heat
from the hot region, thereby cooling down the system
temperature.
[0042] Similarly, if it is desirable to have the system output on
the hot region, then the system could function as a heater. In this
variation, for example, the input (303) and output (305) channels
of hot region (304) could be connected to a heating pad, or other
heating or warming device. In some variations a radiator may be
desirable in order to transfer heat to, and therefore, heat up, the
hot region. Again, while the fluid channel is depicted traversing
through the hot region, it is also possible for the fluid channel
to traverse through the cold region, and it should be understood
that the systems described here are not so limited so as to exclude
these variants.
[0043] One illustrative example of how system (300) may be operated
is depicted in FIG. 3A. As shown in FIG. 3A, element (312) is
partially in contact with fluid channel (306). Movement of element
(312) into and out of fluid channel (306) controls the heat
exchange between the hot and cold region, and thus the system
temperature. This movement can be controlled by a user by
adjustment knob (316). As noted above, the knob (316) may be any
knob suitable for facilitating movement of element (312) into, or
out of, fluid channel (306).
[0044] As the user turns adjustment knob (316), element (312) is
moved into the path of fluid flow in the fluid channel, thereby
exposing more of element's (312) surface area to the passing fluid.
As more of the element's surface area gets exposed to the passing
fluid, the more heat gets transferred. The element (312) can take
any suitable configuration, and be made of any suitable material.
In some variations, the element (312) is made out of a highly
conductive material having an o-ring. In some variations, the
element is made out of a metal selected from the group consisting
of aluminum, copper, silver, and gold. Mixtures of metals or alloys
may also be suitable. In some variations, the element has a thermal
conductivity of at least 50(W)(m.sup.-1)(.degree. C..sup.-1).
[0045] System (318) of FIG. 3B illustrates a system similar to that
of system (300) of FIG. 3A, however, in FIG. 3B, the temperature of
the system is regulated, at least in part, by thermal expansion of
bimetal (334). As shown in FIG. 3B, the system (318) comprises a
refrigeration device (320), and a controller (330). The
refrigeration device (320) comprises a hot region (322) having a
fluid channel (324) therethrough, a cold region (326), and a TEM
(328). The controller comprises an element of high thermal
conductivity (332), a bimetal (334), and a bimetal securing screw
(336).
[0046] In operation, the system of FIG. 3B functions in a similar
fashion to the system of FIG. 3A, however, whereas the system of
FIG. 3A is user controlled and operates only upon relative
temperatures, the system of FIG. 3B is automatically controlled
about a range of temperatures, which are typically determined by
the selection of the bimetal material. As noted above in the
description of the systems of FIGS. 11B and 2B, the temperature of
the system is regulated, at least in part, by thermal expansion of
the bimetal. That is, as bimetal (334) expands, it moves element
(332) into the path of fluid flow, thereby effecting greater heat
transfer.
[0047] FIG. 3C illustrates another variation of a solid-liquid
system, in which the temperature is user adjustable about a fixed
set point. As shown in FIG. 3C, the system (338) comprises a
refrigeration device (340) and a controller (350). The
refrigeration device (340) comprises a hot region (342) having a
fluid channel (344) traversing therethrough, a cold region (346),
and a TEM (348). The controller (350) comprises an element of high
thermal conductivity (352), a bimetal (354), a bimetal securing
screw (356), a user adjustment knob (360), and a bimetal threaded
adjuster (358).
[0048] The adjustment knob (360) allows a user to adjust the
temperature of the system within a set range of temperatures, the
range typically determined by the selection of the bimetal used to
make bimetal strip (354). As noted above, the adjustment knob (360)
may be any acceptable knob. Similarly, bimetal securing screw (356)
may be made out of any suitable material, for e.g., the same
material used to make securing screws (130) and (150).
[0049] FIGS. 4A-4C illustrate systems where a gas and a solid are
used at the hot and cold region junctions to transfer heat. That
is, opposed to the systems described in FIGS. 3A-3C, which utilize
fluids to dissipate heat, the hot region of the systems illustrated
in FIGS. 4A-C, dissipate heat using a gas. A heat sink having a
gaseous current running by it is illustratively depicted in FIGS.
4A-C.
[0050] Turning now to FIG. 4A, there is shown a user adjustable
system (400) comprising a refrigeration device, and a controller
(410). The refrigeration device comprises a hot region (404), a
cold region (406), and a TEM (408). The controller (410) comprises
a vent door (412), and a housing (414). Also shown in FIG. 4A is a
user adjustment knob (420). Depicted in FIG. 4A is a heat sink
(418), here in the form of a ridged structure as part of hot region
(404).
[0051] In operation, the gas enters system (400) through opening
(416), and exits on the right when vent door (412) is open. When
the vent door (412) is closed, convection is restricted, and the
gas flow cannot exit. Any number of suitable gases can be used with
the systems described here. For example, the gas may be air, or
some other inert gas. In the system depicted here, the rate of heat
dissipation is regulated by controlling the path of the gas as it
crosses hot region (404) and heat sink (418).
[0052] The user adjustment knob (420) controls the vent door (412).
That is, as knob (420) is turned, the vent door (412) opens, and
more gas is permitted to escape. If the knob is turned in the
opposite direction, the vent door closes. In this way, the vent
door is used to regulate the amount of gas flow exiting the system.
The more gas that passes over the hot region (404), the more heat
that gets dissipated. That is, when the vent door (412) is
completely open, there is maximum cooling or heat dissipation.
[0053] The vent door (412) need not be made out of any particular
material. For example, the vent door (412) could be made out of a
conductive or insulating material. For example, sheet metal or
engineering polymers may be used. Suitable knobs were described
above, as were materials and dimensions suitable for the hot and
cold regions.
[0054] FIG. 4B illustrates a system (422) having a fixed
temperature set point. As shown in FIG. 4B, the system comprises a
refrigeration device (424), and a controller (430). The
refrigeration device (424) comprises a hot region (426), a cold
region (428), and a TEM (430) positioned between the two and in
thermal contact therewith. The controller (430) comprises a vent
door (432), a housing (434), a bimetal (436), and a bimetal
securing screw (428).
[0055] System (422) of FIG. 4B illustrates a system similar to that
of system (400) of FIG. 4A, however, in FIG. 4B, the temperature of
the system is regulated, at least in part, by thermal expansion of
bimetal (436). That is, whereas the system of FIG. 4A is user
controlled and operates only upon relative temperatures, the system
of FIG. 4B is automatically controlled about a range of
temperatures, which are typically determined by the selection of
the bimetal material. As bimetal (436) expands, it pushes on a
connecting element (here shown as a rod) attached to vent door
(432), thereby causing the vent door to close.
[0056] Another variation of the systems described herein is
illustrated in FIG. 4C, which depicts a user adjustable system
(444) adjustable about a fixed temperature set point. As shown in
FIG. 4C, the system comprises a refrigeration device (446), and a
controller (454). The refrigeration device (446) comprises a hot
region (448), a cold region (450), and a TEM (452) positioned
between the two and in thermal contact therewith. The controller
(454) comprises a vent door (456), a housing (458), a bimetal
(462), and a bimetal securing screw (460). Also shown in a user
adjustment knob (468).
[0057] The adjustment knob (468) controls the vent door (456) and
therefore allows a user to adjust the temperature of the system
within a set range of temperatures, the range typically determined
by the selection of the bimetal used to make bimetal strip (462).
As noted above, the adjustment knob (468) may be any acceptable
knob. Similarly, bimetal securing screw (460) may be made out of
any suitable material, for e.g., the same material used to make
securing screws (130) and (150) and (356).
[0058] Although illustrative variations of the systems and
controllers have been described above, it will be evident to a
skilled artisan that various changes and modifications may be made
without departing from the true scope and spirit of the systems and
controllers described above and herein claimed.
* * * * *