U.S. patent application number 13/235371 was filed with the patent office on 2012-04-19 for smart building systems and methods.
Invention is credited to Bao Q. Tran.
Application Number | 20120095605 13/235371 |
Document ID | / |
Family ID | 45934816 |
Filed Date | 2012-04-19 |
United States Patent
Application |
20120095605 |
Kind Code |
A1 |
Tran; Bao Q. |
April 19, 2012 |
SMART BUILDING SYSTEMS AND METHODS
Abstract
An appliance includes a memory storage location storing a flag
indicative of a predicted demand-response (DR) period; and a
controller coupled to the flag to autonomously place the appliance
in an energy shedding mode during the predicted DR period.
Additionally, a method is disclosed to fabricate a building
structure includes depositing a phase change material (PCM) on a
surface exposed to a conditioned air flow; and forming air channels
on the PCM to increase thermal contact between the PCM and the
conditioned air flow.
Inventors: |
Tran; Bao Q.; (Saratoga,
CA) |
Family ID: |
45934816 |
Appl. No.: |
13/235371 |
Filed: |
September 17, 2011 |
Current U.S.
Class: |
700/285 ;
700/275; 700/276; 700/282; 700/296 |
Current CPC
Class: |
F24F 5/0021 20130101;
G05D 23/1923 20130101; B05D 5/00 20130101 |
Class at
Publication: |
700/285 ;
700/296; 700/282; 700/275; 700/276 |
International
Class: |
G06F 1/32 20060101
G06F001/32; G05D 23/19 20060101 G05D023/19 |
Claims
1. An appliance, comprising: a memory storage location storing a
flag indicative of a predicted demand-response (DR) period; a
non-electrical energy source to provide temporary energy during the
DR period; and a controller reading the flag to autonomously place
the appliance in an energy shedding mode during the predicted DR
period.
2. The appliance of claim 1, wherein the predicted DR period occurs
when the specified duty cycle comprises 60 hertz and the current AC
power duty cycle comprises about 59.5 hertz or less.
3. The appliance of claim 1, comprising: a wide area network
coupled to the sensor; and a server coupled to the wide area
network, wherein for each appliance the server stores a location, a
user preference, and appliance properties, and wherein the server
receives periodic operating state update and time stamp from each
appliance.
4. The appliance of claim 3, wherein the controller indicates the
location of the appliance using an internet protocol (IP)
address.
5. The appliance of claim 3, wherein the controller indicates the
location of the appliance using an address selected from one of:
(consisting of) a user entered address, an address stored in
another appliance, and an address determined by a positioning
system.
6. The appliance of claim 1, wherein the server determines a first
group of appliances in an uninterruptible phase and sends a DR
override instruction to the controller(s) in the first group.
7. The appliance of claim 1, wherein the server modulates
operations of appliances to avoid stressing the electrical
grid.
8. The appliance of claim 1, wherein the appliance comprises a
sensor compares the current AC duty cycle against the specified AC
duty cycle and sets the flag indicative of a predicted
demand-response (DR) period.
9. The appliance of claim 1, comprising a power sensor external to
the appliance, wherein the power sensor compares the current AC
duty cycle against the specified AC duty cycle and sets the flag
indicative of a predicted demand-response (DR) period.
10. The appliance of claim 1, wherein the appliance is a
refrigerator, further comprising: an ice energy storage chamber
providing a predetermined cold energy for a refrigerated volume for
the predicted DR period; and a fan to circulate cold air from the
ice energy storage chamber inside the refrigerated volume during
the predicted DR period.
11. The appliance of claim 1, wherein the appliance is a
refrigerator, further comprising a phase change material coupled to
the refrigerated volume to maintain the refrigerated volume at a
predetermined temperature during the predicted DR period.
12. The appliance of claim 1, wherein the appliance is a
refrigerator and wherein the controller modulates compressor
operation to reduce power consumption during the predicted DR
period.
13. The appliance of claim 1, wherein the appliance is a
refrigerator, and wherein the controller precharges the
refrigerator prior to the predicted DR period.
14. The appliance of claim 13, wherein the appliance is a
refrigerator, and wherein the controller precharges the
refrigerator based on weather or warning from an authority.
15. The appliance of claim 1, wherein the appliance is a
refrigerator, comprising an ice storage to store coolth during
night and used for air-conditioning during day.
16. The appliance of claim 1, wherein the appliance is a water
heater, comprising: a back-up heated energy storage chamber to
store a reserve heated water to maintained a predetermined
temperature output for the water heater during the predicted DR
period; and a valve to mix the reserve heated water with the water
in the main water heater tank during the predicted DR period.
17. The appliance of claim 15, wherein the appliance is a water
heater, further comprising a phase change material coupled to the
water volume to maintain the water at a predetermined temperature
during the predicted DR period.
18. The appliance of claim 15, wherein the appliance is a water
heater and wherein the controller modulates heater operation to
reduce power consumption during the predicted DR period.
19. The appliance of claim 15, wherein the appliance is a water
heater, and wherein the controller precharges the water heater
prior to the predicted DR period.
20. The appliance of claim 18, wherein the appliance is a water
heater, and wherein the controller precharges the water heater
based on weather or warning from an authority.
21-28. (canceled)
Description
BACKGROUND
[0001] The present invention relates to smart building.
[0002] The ever increasing need for electricity has historically
been satisfied by building more power plants. However, the
projected load growth and other external forces are pointing to
projected peak capacity shortage in the near future.
[0003] One option to meet peak demand is called demand-response
(DR). DR uses technology and incentives to change electricity
consumption by end-use customers. It can result in a reduction in
energy consumption at times of peak use and at times of high
wholesale market prices. DR offers benefits to both utilities and
consumers in the form of increased electric system reliability and
reduced price volatility. It uses a wide range of technologies
offering a variety of options for both peaking and energy
capacities across the electrical system.
[0004] Energy demand at a premise varies over the time of day. In a
typical home there is a peak in the morning when the family gets
up, turns on lights, radios and televisions, cooks breakfast, and
heats hot water to make up for the amount used in showers. When the
family leaves for work and school it may leave the clothes washer
and dishwasher running, but when these are done, demand drops to a
lower level but not to zero as the air conditioners, refrigerators,
hot waters and the like continue to operate. Usage goes up as the
family returns, peaking around dinner when the entire family is
home. This creates the typical "double hump" demand curve.
[0005] Businesses tend to follow different patterns depending on
the nature of the business. Usage is low when the office is closed
and relatively constant when the office is open. In extreme
climates where air conditioning cannot be cut back overnight,
energy use over the course of the day is more constant. Businesses
such as restaurants may start later in morning and their peaks
extend farther into the evening. A factory with an energy intensive
process operating three shifts may show little or variation over
the course of the day.
SUMMARY
[0006] In one aspect, an appliance includes a memory storage
location storing a flag indicative of a predicted demand-response
(DR) period such as from a utility or when a current alternating
current (AC) duty cycle differs from a specified AC duty cycle by a
predetermined variance. The appliance includes a controller coupled
to the flag to autonomously place the appliance in an energy
shedding mode during the predicted DR period.
[0007] Implementation of the above system may include one or more
of the following. The predicted DR period occurs when the specified
duty cycle comprises 60 hertz and the current AC power duty cycle
comprises about 59.5 hertz or less. The appliance can include a
wide area network coupled to the sensor; a server coupled to the
wide area network, wherein for each appliance the server stores a
location, a user preference, and appliance properties, and wherein
the server receives periodic operating state update and time stamp
from each appliance. The controller can determine the location of
the appliance using an internet protocol (IP) address. The
controller indicates the location of the appliance using an address
selected from one of a user entered address, an address stored in
another appliance, and an address determined by a positioning
system. The server determines a first group of appliances in an
uninterruptible phase and sends a DR override instruction to the
controller(s) in the first group. The server modulates operations
of appliances to avoid stressing the electrical grid. The appliance
can include a sensor that compares the current AC duty cycle
against the specified AC duty cycle and sets the flag indicative of
a predicted demand-response (DR) period. An external power sensor
can be placed external to the appliance, wherein the power sensor
compares the current AC duty cycle against the specified AC duty
cycle and sets the flag indicative of a predicted demand-response
(DR) period.
[0008] In one implementation, the appliance can be a refrigerator
with an ice energy storage chamber providing a predetermined cold
energy for a refrigerated volume for the predicted DR period; and a
fan to circulate cold air from the ice energy storage chamber
inside the refrigerated volume during the predicted DR period. The
refrigerator can include a phase change material coupled to the
refrigerated volume to maintain the refrigerated volume at a
predetermined temperature during the predicted DR period. The
controller modulates compressor operation to reduce power
consumption during the predicted DR period. The controller
precharges the refrigerator prior to the predicted DR period. The
controller precharges the refrigerator based on weather or warning
from an authority. The refrigerator can include ice storage to
store coolth when power is available and used during the DR period.
The fact that water is a pure substance and that making ice does
not involve a chemical reaction is one reason that ice storage is a
relatively trouble free system.
[0009] In another implementation, the appliance is a water heater
with a back-up heated energy storage chamber to store a reserve
heated water to maintained a predetermined temperature output for
the water heater during the predicted DR period; and a valve to mix
the reserve heated water with the water in the main water heater
tank during the predicted DR period. The water heater can include a
phase change material coupled to the water volume to maintain the
water at a predetermined temperature during the predicted DR
period. The water heater controller modulates heater operation to
reduce power consumption during the predicted DR period. The
controller can precharge the water heater prior to the predicted DR
period or based on weather or warning from an authority.
[0010] In another implementation, the appliance can be a washer
with a digitally actuated latch to secure a washer door during the
predicted DR period. If the washer is in an uninterruptible
cleaning operation during the predicted DR period, the controller
reduces power consumption during the predicted DR period and
subsequently repeats the uninterruptible operation after the
predicted DR period. Further, if the washer is in an extendible
cleaning operation during the predicted DR period, the controller
reduces power consumption during the predicted DR period and
subsequently completes the extendible operation after the predicted
DR period. The washer appliance can include a back-up heated energy
storage chamber to store a reserve heated water to maintained a
predetermined temperature output for the heater during the
predicted DR period; and a mixer to mix the reserve heated water
with cold water to maintain a predetermined washing temperature
during the predicted DR period. A data input device can indicate
the use of detergent additive or bleach usage, wherein the
processor ignores the predicted DR period to avoid damage to items
in the washer.
[0011] In another aspect, systems and methods are disclosed to
fabricate a building structure includes depositing a phase change
material (PCM) on a surface exposed to a conditioned air flow; and
forming air channels on the PCM to increase thermal contact between
the PCM and the conditioned air flow.
[0012] In another aspect, a method to fabricate a building
structure mixing a texture aggregate filler mixed with a phase
change material (PCM), said filler being selected from the group
consisting of perlite, glass microballoons, glass bubbles, phenolic
microballoons, and microspheres; and placing the PCM with the
filler on a surface exposed to a conditioned air flow to increase
thermal contact between the PCM and the conditioned air flow.
[0013] Implementations of the above aspect may include one or more
of the following. The building structure comprises a ceiling tile
or an underfloor air distribution (UFAD) panel. The process
includes forming elongated hollow PCM structures. The elongated
hollow PCM structures are fabricated in advance and attached to the
building material during fabrication or during shipping. The
elongated hollow PCM structures are formed by dipping a scaffold
into melted PCM. The process includes extruding the elongated
hollow PCM structures with a predetermined cross-sectional shape.
The cross-sectional shape comprises one of: circular, hexagonal,
rectangular, octahedron. The process includes forming a first layer
of elongated hollow PCM structures and a second layer of elongated
hollow PCM structures above the first layer. The process includes
forming air channels with grooves positioned on two adjacent sides
of the building materials to allow air flow through the PCM
regardless of orientation of the building material. The process
includes spraying PCM onto the surface before forming air channels
with a shaped tool. The process includes pouring PCM onto the
surface before forming air channels with a shaped stamping tool.
The process includes rolling PCM onto the surface before forming
air channels with a shaped roller. The process includes dipping the
surface into PCM and then forming the air channels with a shaped
tool. The process includes microencapsulating the PCM. The process
includes characterizing PCM properties and predicting building
performance with the characterized PCM properties. The process
includes pre-charging a building by cooling the PCM during a period
of non-peak energy consumption and reducing energy consumption
during a peak period.
[0014] In another aspect, a method to fabricate a building
structure includes mixing a phase change material (PCM) with a
texture aggregate filler, said filler being selected from the group
consisting of perlite, glass microballoons, glass bubbles, phenolic
microballoons, and microspheres; spraying the aggregate filler PCM
on a surface exposed to a conditioned air flow to increase thermal
contact between the PCM and a conditioned air flow.
[0015] Implementations of the above aspect may include one or more
of the following. The process includes rolling the texture on the
PCM with a roller. The process includes using a crow's foot stomp
brush to form a texture to thermally interact with the air flow.
The process includes stamping a texture on the PCM.
BRIEF DESCRIPTION OF THE FIGURES
[0016] FIGS. 1A and 1B show an exemplary smart grid home.
[0017] FIG. 2A and FIG. 2B show exemplary DR responsive appliances
such as an exemplary water heater, an exemplary refrigerator, an
exemplary dish washer, an exemplary clothes washer, and an
exemplary oven.
[0018] FIG. 3 shows an exemplary refrigerator.
[0019] FIG. 4 shows an exemplary water heater.
[0020] FIG. 5 shows an exemplary clothes washer.
[0021] FIG. 6 shows an exemplary dish washer.
[0022] FIGS. 7-11 show exemplary phase change material (PCM)
ceiling tiles or floor panels.
[0023] FIGS. 12A-12C show exemplary PCM fabrication equipment.
DESCRIPTION
[0024] FIG. 1A shows an exemplary smart grid home. The smart grid
home includes smart building materials such as smart tile
ceiling/floor panels and windows/window shades, as discussed in
depth below. In one embodiment, the home may include a roof
refrigeration unit to store energy. Ice is one technical modality
currently used in commercial building applications to store
"coolth" at night by running refrigeration equipment. During the
day, the refrigeration equipment is turned off to reduce peak
electrical demand. To store heat (from the sun, for example),
however, a different phase change material is needed. Alternatives
to ice can be used. For example, paraffin, alone, and solid-state
phase change materials (PCM) can be incorporated into building
products such as wallboard and concrete. Microencapsulated PCM can
be used in window cover or fabrics to reduce temperature
fluctuations.
[0025] The windows allow sunlight or solar radiation into a
building or structure when the ambient temperature is low and
substantially block solar radiation when the ambient temperature is
high, especially when sunlight is directly on the window. This
house provides windows that allow passive solar heating and
daylighting on colder days and still provide significant
daylighting, while blocking solar heat build-up on warmer days,
especially from sunlight shining directly on or through the windows
of this invention. This house also provides thermochromic devices
such as variable transmission shutters for use as lenses or
filters.
[0026] Ultimately, it is the outdoor or ambient temperature and the
directness of the sun's rays that determine the need for energy
blocking character of windows. In a number of embodiments of this
invention, the windows of this invention spontaneously change to
provide energy blocking under the appropriate conditions of
temperature and directness of sunlight without the control
mechanisms and user intervention required by most alternate
technologies under consideration for use as dimmable windows. Other
embodiments of this invention provide windows that can be
controlled by users or be controlled automatically by, for example,
electronic control mechanisms, if so desired.
[0027] Windows have residual light energy absorbing character such
that when exposed to sunlight, (especially direct sunlight on warm
or hot days), the temperature of at least a portion of the total
window structure is raised significantly above the ambient, outdoor
temperature. The windows and devices combine thermochromic
character with this residual light energy absorbing character,
juxtaposed in such a manner that there is an increase in
temperature of the materials responsible for the thermochromic
character when there is an increase in temperature due to sunlight
exposure of the materials responsible for the residual light energy
absorbing character. The thermochromic character is such that the
total light energy absorbed by the window increases as the
temperature of the materials responsible for the thermochromic
character is increased from the ambient, outdoor temperature to
temperatures above the ambient, outdoor temperature.
[0028] The residual light energy absorbing character is provided by
static light energy absorbing materials and/or thermochromic
materials that have some light energy absorbing character at
ambient, outdoor temperatures. Preferably, any light energy
absorbing character of the thermochromic materials at ambient
outdoor, temperatures that contributes to the residual light energy
absorbing character is due to the more colored form of the
thermochromic materials that exists because of the thermal
equilibrium between the less colored and more colored forms at
outdoor, ambient temperatures or is due to the coloration of the
less colored form and is not due to photochromic activity of the
thermochromic materials. Preferably, the residual light energy
absorbing character is such that the window is capable of absorbing
about 5% or more and more preferably about 10% or more of the
energy of solar irradiance incident on the window or device apart
from any absorption changes caused by sunlight exposure.
Preferably, the residual light energy absorbing character is such
that there is a temperature increase in the materials responsible
for the thermochromic character of at least 10.degree. C. and more
preferably of at least 20.degree. C. above the ambient, outdoor
temperature when the window or device is exposed to direct or full
sunlight.
[0029] The thermochromic character can be provided by essentially
any material or materials which change reversibly from absorbing
less light energy to absorbing more light energy as the temperature
of the material or materials is increased. It is preferred that the
thermochromic character be provided by materials that have a
smaller absorption at outdoor, ambient temperatures on warm and hot
days and have an increase in absorption when the temperature of the
materials responsible for the thermochromic character is increased
at least 10.degree. C. It is preferred that the thermochromic
character be provided by materials that have even less absorption
at outdoor, ambient temperatures on cool and cold days and a less
significant increase in absorption when the temperature of the
window increases due to exposure to direct or full sunlight on cool
and cold days.
[0030] The windows optionally combine other characteristics like
low emissivity, infrared light reflectance, barrier properties,
protective overcoating, multipane construction and/or special gas
fills to provide energy efficient windows.
[0031] Energy efficient windows and devices of the invention can
have one or more thermochromic layers which change from absorbing
less light energy to absorbing more light energy as the temperature
of the thermochromic layer(s) is increased. For many of the
thermochromic layers used in the invention, this means a change
from less colored to more colored as the temperature of the
thermochromic layer(s) is increased.
[0032] Windows and devices of the invention can have one or more
substrates, (i.e. window pane, panel, light or sheet). The
substrate may be a thermochromic layer or the substrate may have
thermochromic layer(s) provided thereon. Windows of the invention
may comprise two or more substrates spaced apart by spaces
containing gas or vacuum.
[0033] Windows optionally include a barrier to short wavelength
light. The short wavelength light may be ultraviolet (UV) light.
The short wavelength light may, optionally, include short
wavelength visible (SWV) light. The barrier may absorb some or all
of the UV and/or SWV light incident on the barrier layer. The
barrier may be a substrate, a portion of a substrate, (e.g., the
barrier may be in a polymeric layer adhering two sheets of glass
together), or the barrier may be a layer provided on a substrate.
The barrier, if present, is located between the sun and the
thermochromic layer and serves to protect and/or modify the
behavior of the thermochromic layer and possibly other layers
present. The barrier can protect other layers, for example, from
photodegradation by UV light and can modify the behavior of the
thermochromic layer by suppressing some or all of the photochromic
character of materials present which have both thermochromic and
photochromic character. In many cases, the thermochromic materials
will be incorporated into a polymeric material which includes an
additive such as a UV stabilizer. While this stabilizer does not
ordinarily provide the equivalent effect of a barrier layer,
devices have been constructed without a barrier layer when a UV
stabilizer is present in the thermochromic layer.
[0034] Windows may have a protective overcoat. This overcoat, if
present, serves to protect the thermochromic layer and optionally
any other layer which may be present from, for example, physical
abrasion, oxygen and environmental contaminants. The thermochromic
layer is located between the sun and the protective overcoat, if it
is present, e.g., a window pane of glass/thermochromic
layer/protective overcoat may be oriented with the overcoat on the
inside surface of the window structure.
[0035] Windows may also have one or more static light energy
absorbing materials. These materials provide relatively constant
light energy absorption, (i.e. absorption which is not
significantly dependent on the temperature or photochemical
processes of the light energy absorbing material). The static light
energy absorbing material(s), if present, serves to provide
residual light energy absorbing character and thus absorbs enough
light energy during direct or full sunlight exposure to raise the
temperature of at least a portion of the window above the ambient
temperature surrounding the window. This helps to make the windows
responsive to the directness of the sunlight. The static light
energy absorbing materials may be contained in a separate layer, in
the substrate, and/or any of the other layers present including the
thermochromic layer as long as the absorbed energy is able to warm
the themochromic material to a temperature at which the
thermochromic material increases in sunlight absorption.
[0036] Windows may have one or more low emissivity, (low-e),
layers. The low-e layer(s) helps provide energy efficiency by its
ability to reflect infrared, (IR), light and/or its ability to
poorly emit or radiate IR light.
[0037] Using the thermochromic layers, the roof can turn white
during summer days to reflect sunlight and minimize heat inside the
house and can turn black during winter months to absorb heat to
warm the house.
[0038] The carpet can also have a multi-component PCM fibre,
wherein a first fibre body consists of a first material comprising
a phase change material and a second fibre body consists of a
second material and encloses the first fibre body, wherein the
phase change material is in raw form and the first material
comprises a viscosity modifier selected from polyolefines having a
density in the range of 890-970 kg/m 3 as measured at room
temperature according to ISO 1183-2 and a melt flow rate in the
range 0.1-60 g/10 minutes measured at 190.degree. C. with 21.6 kg
weight according to ISO 1133.
[0039] The expression "raw form" is intended to mean that the PCM
is introduced in its raw form at the manufacturing of the
multi-component fibre, i.e. that the PCM is not encapsulated, the
PCM is neither carried on or by another material solid at the
spinneret temperature during spinning of the multi-component fibre,
such as soaked into a porous structure, wherein the structure is
solid at the spinneret temperature during spinning of the
multi-component fibre. Thus, the PCM is considered as in "raw form"
in spite of it being mixed with the viscosity modifier at
manufacturing the multi-component fibre.
[0040] Polymers having a melt flow rate in the range 0.1 to 60 g/10
minutes measured at 190.degree. C. with 21.6 kg weight are suitable
as viscosity modifiers in the multi-component fibre. Many of the
efficient PCM materials are low molecular compounds and such
compounds possess low viscosities at the relevant processing
temperatures (180-300.degree. C.). In order to make multi-component
fibres with a sheath material, the second material, having a higher
viscosity at the processing temperature, the inventors have now
found that if the phase change material is mixed with a polyolefin
having a melt flow rate in the range 0.1-60 g/10 minutes, a fibre
having high latent heat and which is strong is obtained. The
polyolefin is a viscosity modifier, which increases the viscosity
of the first material of the multi-component fibre.
[0041] A low amount of a viscosity modifier having a melt flow rate
in the range 0.1-60 g/10 minutes may be used, which is an advantage
for the thermal efficiency in terms of specific latent heat and at
the same time allow the full utilisation of the inherent specific
latent heat of melting/crystallisation of the phase change
material. If a higher value than 60 g/10 minutes is used, the
viscosity will be too low and the mixture will not be possible to
process a fibre. The mixture will be "watery", i.e. very thin. A
value lower than 0.1 g/10 minutes of the viscosity modifier might
lead to curling of the fibres and fibre spinning may not be
possible.
[0042] As shown in FIG. 1B, apparatus 101 includes a unit 103
comprising a controller 104 and an internal storage device 105.
Internal storage device 105 may comprise, for example, a plurality
of lead-acid or nickel-metal-hydride storage batteries for storing
electrical energy, and/or large capacitors. External storage device
106 may be optionally included to store additional electrical
energy. As explained in more detail herein, storage devices 105 and
106 may provide power to various devices during times of electrical
grid outages or during periods where electrical grid costs exceed
certain thresholds, and they may be used to sell power back to the
electrical utility during times that are determined to be
favorable. The storage capacities of devices 105 and 106 may be
selected to suit a particular environment, such as the needs of a
typical home residence, business, or other electrical consumer.
[0043] Storage in the form of compressed air is usually discounted
due to the poor thermodynamic efficiency, but the capital cost is
low and in some cases the marginal value of solar power is zero
(when supply exceeds demand the excess cannot be sold or stored by
other means), so compressed air storage may be practical in some
embodiments of the invention. Finally, in some specific locations
it may be possible to store power by pumping water to an elevated
water tower or reservoir (pumped storage) which could increase
storage capacity by another factor of 10. Power electronics,
including inverters for converting DC electrical energy into AC
energy, circuit breakers, phase converters and the like, may also
be included but are not separately shown in FIG. 1.
[0044] Controller 104 may comprise a computer and memory programmed
with computer software for controlling the operation of apparatus
101 in order to receive electrical power from power sources 109
through 115 and to distribute electrical power to devices 116
through 122. Further details of various steps that may be carried
out by such software are described in more detail herein.
[0045] As the building may contain non-electrical energy storage
materials embedded in a building, the controller precharges the
materials embedded in at least a ceiling, a floor, window,
wallboard, or concrete of a building in advance of an expected DR
period. In one embodiment, the controller creates in advance
computer models of the non-electrical energy storage materials or
sources and uses the models to precharge the non-electrical energy
storage material or the non-electrical energy source in advance of
an expected DR period. The computer model can be statistical or
non-statistical. For example, Hidden Markov Models (HMMs) can be
used to model building energy behavior and such models can be used
to precharge the building thermal envelopes.
[0046] The ability to pre-charge the building supports utility DR
programs, since off-peak power such as night time can be used to
store energy in the non-electrical energy storage materials and
non-electrical energy storage sources of energy and such energy can
be used to supplement the reduced power during the DR period.
[0047] Controller 104 and internal storage device 105 may be housed
in a unit 103 such as a metal rack having appropriate cabling and
support structures. Apparatus 101 also includes a user interface
102 for controlling the operation of unit 103. The user interface
may comprise a keypad and CRT, LED or LCD display panel or vacuum
fluorescent type; a computer display and keyboard; or any other
similar interface. The user interface may be used to select various
modes of operation; to display information regarding the operation
of the apparatus; and for programming the apparatus.
[0048] An optional control center 108 may be provided to transmit
commands to apparatus 101 through a network, such as WAN 107 (e.g.,
the Internet). Control center 108 may be located at a remote
location, such as a central control facility, that transmits
commands to a plurality of units 101 located in different homes or
businesses. In addition to transmitting commands, control center
108 may transmit pricing information (e.g., current price of
electricity) so that controller 104 may make decisions regarding
the control and distribution of electricity according to various
principles of the invention.
[0049] Apparatus 101 is coupled to the electric utility grid 115
through a power interface (not shown), which may include circuit
breakers, surge suppressors and other electrical devices.
Electricity may be supplied in various forms, such as 110 volts or
240 volts commonly found in homes. A backup generator 114 may also
be provided and be controlled by apparatus 101 when needed. One or
more alternative energy sources 109 through 113 may also be
provided in order to provide electrical power to the apparatus.
Such sources may include photovoltaic (PV) cells 109, which may be
mounted on a roof of the home or business; micro-hydroelectric
power generators 110, which generate power based on the movement of
water; gas turbines 111; windmills or other wind-based devices 112;
and fuel cells 113. Other sources may of course be provided.
[0050] During normal operation, power from one or more of the power
sources can be used to charge storage units 105 and 106 and/or to
meet demand in addition to electric grid 115. During power outages
or brownouts from grid 115, these additional power sources (as well
as storage units 105 and 106) can be used to meet energy demand.
Additionally, surplus power can be sold back to the power grid
based on optimization of supply and demand calculations as
explained in more detail herein.
[0051] The bold lines shown in FIG. 1 indicate electrical
distribution paths. Control paths to and from the various devices
are not separately shown but are implied in FIG. 1.
[0052] One or more power-consuming devices 116 through 122 may also
be controlled by and receive power from apparatus 101. These
include one or more sensors 116 (e.g., thermostats, occupancy
sensors, humidity gauges and the like);
heating/ventilation/air-conditioning units 117; hot water heaters
118; window shades 119; windows 120 (e.g., open/close and/or tint
controls); and one or more appliances 121 (e.g., washing machines;
dryers; dishwashers; refrigerators; etc.). Some appliances may be
so-called "smart" appliances that can receive control signals
directly from apparatus 101. Other conventional appliances can be
controlled using one or more controllable relays 122. It is not
necessary in all embodiments that apparatus 101 directly provide
electricity to devices 116 through 112. For example, apparatus 101
could be tied into the electrical power system in a home or
business and electricity would be supplied through that path to the
devices. Appropriate cut-off devices and bypass switches would then
be used, for example, in the event of a power outage to disconnect
the home wiring system from the electrical grid and to connect
apparatus 101 to the wiring network. Such schemes are conventional
and no further details are necessary to understand their
operation.
[0053] The next several figures show exemplary DR responsive
appliances including an exemplary water heater, an exemplary
refrigerator, an exemplary dish washer, an exemplary clothes
washer, and an exemplary oven.
[0054] FIG. 2A shows an exemplary appliance 6 with a processor 4
and embedded memory storage location storing a flag indicative of a
predicted demand-response (DR) period when a current alternating
current (AC) duty cycle differs from a specified AC duty cycle by a
predetermined variance. This is detected by AC duty cycle detector
2. The processor or controller 4 is connected to the detector or
sensor 2 to autonomously place the appliance in an energy shedding
mode during the predicted DR period without receiving an explicit
load shedding command from a utility or a power generator.
[0055] In one embodiment, the predicted DR period occurs when the
specified duty cycle comprises 60 hertz and the current AC power
duty cycle comprises about 59.5 hertz or less. The appliance can
include a wide area network coupled to the sensor; a server coupled
to the wide area network, wherein for each appliance the server
stores a location, a user preference, and appliance properties, and
wherein the server receives periodic operating state update and
time stamp from each appliance. The controller can determine the
location of the appliance using an internet protocol (IP) address.
The controller indicates the location of the appliance using an
address selected from one of a user entered address, an address
stored in another appliance, and an address determined by a
positioning system. The server determines a first group of
appliances in an uninterruptible phase and sends a DR override
instruction to the controller(s) in the first group. The server
modulates operations of appliances to avoid stressing the
electrical grid. The appliance can include a sensor that compares
the current AC duty cycle against the specified AC duty cycle and
sets the flag indicative of a predicted demand-response (DR)
period. An external power sensor can be placed external to the
appliance, wherein the power sensor compares the current AC duty
cycle against the specified AC duty cycle and sets the flag
indicative of a predicted demand-response (DR) period.
[0056] Preferably, the control system of each appliance is done
with digital signal controllers with smaller, quieter motors with
energy efficiency as high as 85%-90%. A high efficiency is
necessary to receive a stamp of approval from a governing body such
as the US Environmental Protection Agency and Department of Energy
ENERGY STAR rating. The appliances also comply with IEC 60730
specification covering mechanical, electrical, electronic, EMC, and
abnormal operation of AC appliances. For microcontrollers, the
specification details new test and diagnostic methods for the
real-time embedded software to ensure the safe operation of
embedded control hardware and software. For larger,
higher-performance products where reliability and motor-control
accuracy are key concerns, isolation products block high voltage,
isolate grounds, and prevent noise currents from entering the local
ground and interfering with or damaging sensitive circuitry. The
digital signal controllers perform digital motor control, Power
Factor Correction, and other system functions. A home mesh network
consisting of home appliances, audio/video equipment, HVAC system,
lighting fixtures, etc connected wirelessly and controlled via a
remote control over ZigBee.TM. network. Thus, appliances can
communicate with each other by creating intelligent home networks
such that, for example, a wash load is completed and a message be
displayed on your TV, or LCD display on your refrigerator or remote
control. With low-power wireless solutions, home owners will
benefit from a universal remote control that: does not require
line-of-sight; has an increased range such that one can remotely
control any ZigBee device from anywhere in the home; allows for
two-way communication.
[0057] In one embodiment, refrigerator is equipped with RFID and
allows customers to keep an up-to-date inventory of their
refrigerated goods and have this information displayed on a video
display that may reside on the refrigerator door. Once RFID tags on
individual household goods become commonplace in the market,
RFID-equipped refrigerators will be able to automatically identify
the item as it is being taken in and out of the unit. This will
happen once the large chain food retailers themselves use RFID as
their main mechanism for receiving payment at the checkout
counter.
[0058] Referring to FIG. 2B, additional details regarding power
management device 16 and appliance 18 according to one possible
embodiment are presented. The power management device 16 and
associated appliance 18 may be referred to as an electrical energy
consumption system.
[0059] The depicted power management device 16 includes an
interface 20 and control circuitry 24. Interface 20 is arranged to
receive operational electrical energy for consumption using the
respective appliance 18. Interface 20 may be referred to as a power
interface and comprise the node described above. Interface 20 may
be implemented using a wall outlet adapter able to receive supplied
residential, commercial, industrial, or other electrical energy in
exemplary configurations. Control circuitry 24 may be embodied as a
microprocessor or other appropriate control architecture.
[0060] The depicted exemplary appliance 18 comprises control
circuitry 30, a plurality of associated loads 50, and a plurality
of relays 52. Control circuitry 30 may be implemented as a
microprocessor or other appropriate control architecture and may
also comprise an associated load 50. Associated loads 50 consume
electrical energy. Relays 52 selectively supply electrical energy
power from grid 14 to respective loads 50. In other configurations,
a single relay 52 may supply electrical energy to a plurality of
loads 50 of a given appliance 18. Other configurations for
controlling the application of electrical energy from interface 20
to load(s) 50 are possible.
[0061] Power management device 16 may be configured according to
the exemplary device arrangements described in the incorporated
patent application. Power management device 16 is arranged in one
embodiment as a discrete device separate from the appliance 18 as
mentioned above. Alternately, power management device 16 may be
implemented entirely or partially using existing components of the
appliance 18. For example, functionality of control circuitry 24
may be implemented using control circuitry 30 to monitor electrical
energy of power distribution system 10 and to control consumption
of electrical energy by one or more of loads 50 responsive to the
monitoring. As described in the incorporated patent application, a
relay (or other switching device not shown in FIG. 2) internal of
device 16 may be used to adjust the amount of electrical energy
consumed by appliance 18. Control circuitry 24 and/or control
circuitry 30 may be arranged to control the operations of the
associated relay (not shown) of device 16. As shown, appliance 18
may comprise associated relays 52 which may be controlled by
control circuitry 24 and/or control circuitry 30. Switching device
configurations other than the described relays may be used.
[0062] In other arrangements, control circuitry 24 may provide
control signals to control circuitry 30 or directly to loads 50 to
control the rate of consumption of electrical energy by loads 50
without the use of relays 52 (accordingly relays 52 may be
omitted). Responsive to the received control signals, control
circuitry 30 may operate to control respective loads 50, or loads
50 may internally adjust rates of consumption of the electrical
energy responsive to directly receiving the control signals from
circuitry 24 or 30.
[0063] According to the specific arrangement of the appliance 18
being controlled, aspects described herein, including monitoring of
electrical energy of system 10 and/or controlling the consumption
of power within appliance 18, may be implemented using circuitry
internal and/or external of the appliance 18. The discussion herein
proceeds with respect to exemplary configurations wherein
monitoring and control operations are implemented by control
circuitry 30. Any alternate configurations may be used to implement
functions and operations described herein.
[0064] Appliances 18 comprise devices configured to consume
electrical energy. Exemplary appliances 18 described below include
temperature maintenance systems, HVAC systems, clothes dryers,
clothes washers, water management systems (e.g., spa and/or pool),
dish washers, personal computer systems, water heaters, and
refrigerators. The described appliances 18 are exemplary for
discussion purposes and other arrangements are possible.
[0065] As shown in the exemplary arrangement of FIG. 2, appliances
18 may individually comprise a plurality of different associated
loads 50 individually configured to consume electrical energy. For
example, for a given appliance 18, one of loads 50 may be a control
load wherein processing is implemented (e.g., 3-5 Volt circuitry of
control circuitry 30) and another of the loads 50 may be a higher
voltage load including exemplary motors, heating coils, etc. The
controller of FIG. 2B can charge an energy reservoir 26 to provide
energy during the DR period. The reservoir 26 can be ice energy for
powering a refrigerator, or hot water to back up a washer or water
heater, for example.
[0066] Consumption of electrical energy by such appliances 18 may
be adjusted by turning off (or otherwise adjusting the operation of
one associated load 50 while leaving another associated load 50
powered (or otherwise unaffected). During exemplary power
management operations, it may be desired adjust an amount of
electrical energy applied to one of the associated loads 50 of a
given appliance 18 (e.g., a high power associated load) while
continuing to provide full (or otherwise unadjusted) amount of
electrical energy to another of the associated loads 50 of the
given appliance 18 (e.g., a low power associated load).
Alternately, power may be adjusted, reduced or ceased for all
associated loads all together.
[0067] Adjustment of the consumption of electrical energy by an
appliance 18 may be implemented responsive to monitoring by
appropriate control circuitry of electrical energy of power
distribution system 10. In one embodiment, a characteristic (e.g.,
system frequency) of the electrical energy is monitored. The
incorporated patent application provides exemplary monitoring
operations of system frequency (e.g., voltage) of electrical energy
supplied by power distribution system 10. Other characteristics of
electrical energy of system 10 may be monitored in other
constructions.
[0068] Responsive to the monitoring, appropriate control circuitry
is configured to adjust an amount of consumption of electrical
energy within at least one of the loads 50 from an initial level of
consumption to another different level of consumption. For example,
as described in the incorporated application, if the system
frequency of the electrical energy deviates a sufficient degree
from a nominal frequency, a threshold is triggered. As described in
the incorporated application, the threshold may be varied at
different moments in time (e.g., responsive to power-up operations
of appliance 18 at different moments in time). In one embodiment,
the varying of the threshold is random.
[0069] Appropriate control circuitry may adjust an amount of
consumption of electrical energy (e.g., via one of loads 50) from
an initial level to another different level (e.g., reduced
consumption mode) responsive to the threshold being triggered.
Thereafter, the control circuitry continues to monitor the
electrical energy. If the frequency returns to a desired range, the
control circuitry may return the operation of the appliance 18 and
load(s) 50 to a normal mode of operation (e.g., a mode wherein an
increased amount of electrical energy is consumed). As described in
the incorporated patent application, a variable length of time may
be used to return the consumption to the initial level and the
variable length of time may be randomly generated in at least one
embodiment.
[0070] Accordingly, the appropriate control circuitry may control
operation of the adjusted load 50 for a period of time at the
adjusted level of electrical energy consumption. During the
adjustment, the control circuitry may maintain the level of
consumption of another load 50 of the appliance 18 at a normal
level of consumption.
[0071] Some arrangements of power management device 16 permit
override functionality. For example, the appropriate control
circuitry may have associated user interface circuitry (not shown)
usable by a user to disable power management operations via an
override indication (e.g., hit a key of the user interface
circuitry). Responsive to the reception of the override indication,
the control circuitry may return the mode of operation of the
affected load 50 to a normal consumption mode (e.g., wherein an
increased amount of electrical energy is consumed compared with the
level of consumption initiated during the power management
operations).
[0072] FIG. 3 shows an exemplary refrigerator. The illustrated
refrigerator 140 includes control circuitry 30i (embodying a
thermostat 142), a heating element 144, a fan 146, a compressor
148, and a solenoid valve 150 in the depicted embodiment. Control
circuitry 30i, heater 144, fan 146, and compressor 148 comprise
exemplary loads 50i in the depicted example. The refrigerator 140
also include an ice energy storage chamber 152. The embodiment uses
ice storage to store coolth and used when the DR period is
active.
[0073] First exemplary power management operations of control
circuitry 30i include adjustment of a temperature set point of
thermostat 142. It may be desired in at least one embodiment to set
a relatively short duration of any temperature adjustment during
power arrangement operations. Another possible power management
operation provides temporary disablement of defrost operations of
heating element 144 (e.g., coupled with unillustrated coils of
refrigerator 140), or adjusting a time of the defrost operations
controlled by control circuitry 30i. In another arrangement,
heating element 144 may be used to provide anti-sweat operations
(e.g., appropriately positioned adjacent an exterior portion of an
unillustrated cabinet of refrigerator 140--for example adjacent to
a door) and power management operations may include temporary
disablement of the anti-sweat operations or otherwise adjusting
such operations to occur at another moment in time wherein power
management operations are not being implemented. Additional
exemplary power management operations include disablement of
interior air circulation operations implemented by fan 146 and/or
controlling operations of compressor 148 (e.g., including
temporarily disabling or reducing the speed of compressor 148).
Additional aspects include implementing a hot gas bypass operation
of compressor 148 using solenoid valve 150 and as described in
further detail above in one example. One other embodiment provides
a multi-stage refrigerator 140 having a plurality of cooling stages
and a power management operation includes controlling the
refrigerator 140 to operate at less than the available number of
cooling stages thereby reducing the amount of energy consumed by
the appliance.
[0074] In one implementation, the refrigerator ice energy storage
chamber provides a predetermined cold energy for a refrigerated
volume for the predicted DR period; and a fan to circulate cold air
from the ice energy storage chamber inside the refrigerated volume
during the predicted DR period. The refrigerator can include a
phase change material coupled to the refrigerated volume to
maintain the refrigerated volume at a predetermined temperature
during the predicted DR period. The controller modulates compressor
operation to reduce power consumption during the predicted DR
period. The controller precharges the refrigerator prior to the
predicted DR period. The controller precharges the refrigerator
based on weather or warning from an authority. The refrigerator can
include ice storage to store coolth when power is available and
used during the DR period. The fact that water is a pure substance
and that making ice does not involve a chemical reaction is one
reason that ice storage is a relatively trouble free system.
[0075] FIG. 4 shows an exemplary water heater. Water heater 150
includes control circuitry 30h (embodying a thermostat 152 in the
illustrated configuration) and a heating element 154. Heating
element 154 is configured to heat water in a main reservoir 156 and
an associated reservoir 158 to a desired temperature in the
depicted configuration. Control circuitry 30h and heating element
154 comprise loads 50h of water heater 150 in one embodiment.
[0076] According to an illustrative embodiment, power management
operations of system 150 and implemented by control circuitry 30h
include adjusting a set point of thermostat 152. For example, the
thermostat set point may be temporarily lowered (e.g., for a period
of tens of seconds, or a few minutes in some examples). In other
exemplary power management operations, control circuitry 30h may
directly disable or provide other control of heating element 154
and gate pre-heated water from the back up reservoir 158 during the
DR period.
[0077] According to additional exemplary aspects, a set point of
any of the thermostats disclosed herein of the various appliances
may be assigned to one of a plurality of possible power management
set points according to a monitored condition of electrical energy
of system 101. For example, a scale of set points may be used
according to the condition of the electrical energy (e.g., the
temperature set point may be decreased at predefined decrements
(1-10 degrees for example) corresponding to the system frequency of
the electrical energy deviating respective predetermined amounts
(e.g., 10 mHz) from the nominal frequency. In accordance with the
described example, the magnitude of adjustment of the thermostat
set point increases as the deviation of the system frequency from
the nominal frequency increases.
[0078] In one implementation, the water heater 150 uses the back-up
heated energy storage chamber 158 to store a reserve heated water
to maintained a predetermined temperature output for the water
heater during the predicted DR period; and a valve to mix the
reserve heated water with the water in the main water heater tank
during the predicted DR period. The water heater can include a
phase change material coupled to the water volume to maintain the
water at a predetermined temperature during the predicted DR
period. The water heater controller modulates heater operation to
reduce power consumption during the predicted DR period. The
controller can precharge the water heater prior to the predicted DR
period or based on weather or warning from an authority.
[0079] FIG. 5 shows an exemplary clothes washer. In one
implementation, the washer has a digitally actuated latch to secure
a washer door during the predicted DR period. If the washer is in
an uninterruptible cleaning operation during the predicted DR
period, the controller reduces power consumption during the
predicted DR period and subsequently repeats the uninterruptible
operation after the predicted DR period. Further, if the washer is
in an extendible cleaning operation during the predicted DR period,
the controller reduces power consumption during the predicted DR
period and subsequently completes the extendible operation after
the predicted DR period. The washer appliance can include a back-up
heated energy storage chamber to store a reserve heated water to
maintained a predetermined temperature output for the heater during
the predicted DR period; and a mixer to mix the reserve heated
water with cold water to maintain a predetermined washing
temperature during the predicted DR period. A data input device can
indicate the use of detergent additive or bleach usage, wherein the
processor ignores the predicted DR period to avoid damage to items
in the washer.
[0080] Referring to FIG. 5, the exemplary clothes washer 160 may
include control circuitry 30d, a heating element 162, and an
agitator motor 164. Heating element 162 is configured to heat water
used in an associated compartment (not shown) of clothes washer 160
configured to receive and wash clothes. Heating element 162 is also
used to heat a water reservoir 168 for use during the temporary DR
period so that washing operations can continue. Agitator motor 164
is configured to oscillate between different rotational directions
or otherwise agitate clothes within the associated compartment
during wash and/or rinse operations. Control circuitry 30g, heating
element 162 and agitator motor 164 comprise associated loads 50g of
clothes washer 160 in the depicted embodiment.
[0081] In one configuration, power management operations of clothes
washer 160 include reducing or ceasing the supply of electrical
energy to heating element 162 to reduce internal temperatures of
water in the associated compartment and/or agitator motor 164 to
reduce motion of the motor 164. The reduction in power by
controlling heating element 162 may be linear and accordingly the
benefits may be directly proportional to the reduction in the water
temperature. The reduction in power to agitator motor 164 may be
proportional to a product of angular acceleration, mass and angular
velocity. A slowing down of agitator motion of motor 164 could
affect both a reduction in acceleration as the motor reverses its
motion as well as angular velocity. In other embodiments, it may be
desired to maintain agitator motor 164 in an operative mode during
an implementation of power management operations with respect to
heating element 162.
[0082] An exemplary clothes dryer may similarly include control
circuitry, a heating element, and a tumbler motor. Heating element
is configured in one embodiment to heat an associated compartment
(not shown) of clothes dryer configured to receive and dry clothes.
Tumbler motor is configured to spin clothes within the associated
compartment during drying operations. In one configuration, power
management operations of clothes dryer include reducing or ceasing
the supply of electrical energy to heating element (e.g., reducing
an amount of current supplied to heating element) and/or tumbler
motor. It may be desired to maintain tumbler motor in an operative
mode during an implementation of power management operations with
respect to heating element.
[0083] FIG. 6 shows an exemplary dish washer. Dish washer 170
includes control circuitry 30f, a water heating element 172, a
forced air heating element 174, and a water pump 176 in but one
embodiment. Dish washer 170 may additionally include a compartment
(not shown) configured to receive to dishes. Water heating element
172 may adjust a temperature of water used to wash dishes using
dish washer 170 in one embodiment. Heating element 172 is also used
to heat a reservoir 178 to provide hot washing water during a DR
period. Forced air heating element 174 adjusts a temperature of air
used to dry the dishes in one implementation. Water pump 176 may
spray water on the dishes during a cleaning and/or rinsing cycle to
provide a dish cleaning action and/or rinsing action. Control
circuitry 30f, heating elements 172, 174, and water pump 176 may
comprise associated loads 50f of dish washer 170.
[0084] Exemplary power management operations of dish washer 170
implemented by control circuitry 30f in one embodiment include
controlling the water heater 172 to reduce a water temperature
boost cycle during wash operations and/or reduce air temperature by
forced air heater 174 during rinsing/drying operations. Reduction
of water temperature provides corresponding linear reductions in
electrical power consumption. Control circuitry 30f may also
control operations of water pump 176 (e.g., reduce the operational
speed of pump 176) during modes of reduced power consumption.
[0085] Turning now to FIG. 7, an exemplary ceiling tile 200 is
shown with phase change materials on one or more air ventilation
structures 202. The phase change material (PCM) contributes to the
energy efficiency of buildings by reducing the peaks in the daily
temperature cycles. As part of normal overnight ventilation, the
warm air in the building is replaced by cold night-time air, which
also reduces the temperature of the building's solid structures
over the course of the night. PCM can increase the heat capacity of
the building, meaning that additional `coldness` can be stored in
the building's structures. With our system, it may be possible that
mechanical air conditioning is not needed at all; as a minimum, the
energy consumption for air conditioning can be reduced. The
structure 202 is hollow at the center to maximize air flow and
thermal conductance between the PCM material and the air. The PCM
structure has a plurality of microencapsulated PCM balls or
capsules with wax or paraffin 208 inside of a polymer coating
208.
[0086] The phase change materials include alkanes, paraffin waxes
and salt hydrates. These materials undergo a reversible solid to
liquid phase change at various transition temperatures.
`Solid-state` phase change materials are those that change from
amorphous to crystalline phases while remaining `solid.` Both
paraffin wax and salt hydrates typically require encapsulation to
contain the liquid phase, which adds to final cost of this PCM.
Salt hydrates are inorganic materials. Inorganic compounds have
twice the volumetric latent energy storage compared to organic
compounds. The organic compounds however, have the advantages of
melting congruently and are non-corrosive. Salt hydrates will melt
incongruently causing phase separation. There are two categories of
solid-state phase change materials: layered perovskites and plastic
crystals. The transition temperature of solid-state phase change
materials in a pure form runs on the higher side for use in passive
applications. By mixing these compounds in various ratios, the
transition temperature can be lowered.
[0087] PCM can use paraffin waxes which are part of a family of
saturated hydrocarbons. The structure is the type
C.sub.nH.sub.2n+2. Those with carbon atoms between five and fifteen
are liquids at room temperatures and are not considered. Normal or
straight chain and symmetrically branched chain paraffin waxes are
the most stable. Typically, paraffin waxes with odd numbers of
carbon atoms are more widely used because they are more available,
more economical and have higher heats of fusion. Paraffin waxes are
composed mainly of alkanes, approximately 75%. Alkanes and paraffin
waxes are both organic compounds. Paraffin can contain several
alkanes resulting in a melting range rather than a melting point.
As the molecular weight increases, the melting point tends to
increase as well. Using different mixtures of alkanes, specific
transition temperatures for paraffin waxes can be attained.
Paraffin waxes and alkanes at the transition temperature melt to a
liquid and solidify upon cooling. They do not have the containment
problems of salt hydrates. The properties of normal paraffin wax
are very suitable for latent heat storage. They have a large heat
of fusion per unit weight, they are non-corrosive, nontoxic,
chemically inert and stable below 500.degree. C. (932.degree. F.).
On melting, they have a low volume change and a low vapor pressure.
Mixing different molecular weight paraffin waxes together can
easily vary melting temperature. Since they are commercially
available, the cost is reasonable. Prime candidates for passive
applications are tetradecane, hexadecane, octadecane and eicosane.
Paraffin wax has a low thermal conductivity. However, the addition
of additives such as graphite could increase the thermal
conductivity. A Boulder, Colo. company, Outlast Technology,
distributes outerwear made of fabrics that incorporate encapsulated
paraffin wax. The Outlast Technology fabric involves the
microencapsulation of microscopic size droplets of paraffin wax.
These encapsulated particles of wax are then incorporated into
fabrics and foams that are used for lining materials.
[0088] Pure octadecane is very close to the defined ideal passive
temperature. By mixing normal alkanes of different molecule
weights, the melting or transition temperature can be altered from
that of the pure form. The latent heat of a blend can be found from
a linear equation, presented as:
Final Blend J/g=(wt. %.sub.mPCM1.times.J/g.sub.mPCM1)+(Wt.
%.sub.mPCM2.times.J/g.sub.mPCM2)+ . . .
[0089] Octadecane in its pure form has a relatively high heat of
fusion with a transition temperature close to an ideal passive
temperature. Its latent heat storage is more than three times
greater than the NPG/PG mixture. Based on thermal storage
capabilities, octadecane is the superior material, followed by the
Kenwax 18.
[0090] Paraffin wax and solid-state phase change materials show the
behavior of under or super cooling. This behavior occurs when the
material does not solidify at the same temperature at which it
melted. Solid-state phase change materials have shown more than a
twenty-degree difference. The difference is not as noticeable in
paraffin waxes. Other phase change materials can be used.
[0091] The PCM structure can be glued or secured to the tile.
Preferably, the composite structure is less than 20% by mass of a
binder material and the remaining mass is a phase change material
(PCM).
[0092] The PCM ceiling tile concept is based on reducing peak
air-conditioning loads in a space. To do this, the space is
overcooled slightly during off peak hour, say to 68 F. Air
returning through the ceiling plenum cools and solidifies the phase
change material on the top of the ceiling tile. During the day the
room thermostat is set to a higher temperature, say 75 F. The air
passing through the plenum, entering the plenum at 75 F, is warmed
further by light fixture ballasts in the ceiling. Without the PCM
ceiling tile the air would return to the air handler at about 80 F
and would be cooled there to about 55 F before being returned to
the spaces to provide cooling. However, with the PCM present, the
warm air will pass over the material and be cooled by the PCMs that
are at 68-70 F. The PCM will liquefy as it absorbs energy from the
air. By the time the air reaches the air handling unit it will have
been cooled to about 70 F compared to the 80 F temperature it would
have arrived at without PCM. On the one hand, the air has to be
cooled from 80 to 55 F or 25 F, on the other the air only has to be
cooled from 70 to 55 F or 15 F. In arid climates this represents a
forty percent reduction in peak cooling load. However, in most
other climates moisture is also removed at the air handler so a
thirty percent (30%) reduction in peak load is possible.
[0093] The system of FIG. 7 reduces the rising cost of
electricity/gas for cooling/heating a building. A derivative, but
increasingly important, problem is environmental impact.
Increasingly, architects and end users are taking electricity
consumption explicitly into account, e.g. by penalizing inefficient
products through the award (or non-award) of LEEDS points. The tile
of FIG. 7 minimizes electricity consumption is (a) directly
economically attractive to an end user, (b) attractive to a
developer (who might incur higher upfront costs but can offer
reduced energy consumption as a virtue to his lessors) and (c)
attractive to architects/specifiers who are seeking energy
efficiency.
[0094] The system performs automatic DR, reduces AC cost by 35% and
shifts the demand peak by automatically releasing cooling energy
during the day and warmth at night. Such systems provide a full
range of options for both peaking and energy capacities across the
electrical system and we pass on the attendant energy savings to
customers. Utilities and consumers benefit through increased
electric system reliability and reduced price volatility.
[0095] FIG. 8 shows an embodiment with two layers of PCM structures
210 and 220. FIG. 9 shows an embodiment with cylindrical PCM
structures 230.
[0096] FIGS. 10A-10C show alternative embodiments. In FIG. 10A, the
structure 240 containing the PCM is rectangular. In FIG. 10B, a
honeycomb structure 250 provides strength and thermal conductance
to maximize energy transfer between ambient air and the PCM
material. In FIG. 10C, the structure 260 is cylindrical.
Alternatively, the structure 260 can be a layer of PCM balls glued
or attached to the tile 200.
[0097] FIG. 11 shows one embodiment with multi-directional air
flow. In this embodiment, a tile or floor panel 300 has a PCM layer
310 with a plurality of ports 312 that crisscross each other from
multiple sides of the tile/floor panel so that the air flow is not
blocked, regardless of the position of the tile or floor panel 300
relative to the airflow. This embodiment allows orientation free
installation of the tile or floor unit. The ports can be fabricated
by depositing a first layer of PCM above a finished tile/floor
panel, curing the first layer of PCM, then depositing a second
layer whose air flow is at a 90 degree off set to conduct air flow
from a different side of the tile/panel and then curing the second
PCM layer. This process can be used to fabricate as many PCM layers
as desired.
[0098] The process is applicable to several porous materials
including cement, ceiling tiles and gypsum wallboards. In case of
gypsum wallboards, the board could be a standard board or a board
with fiberglass (the fiberglass is added to increase internal bond
strength). If an increase of the board internal thermal
conductivity is necessary, the board could contain metallic fibers.
If an amount of PCM larger than what the board can retain is
needed, the board could contain a wetting agent. If inflammability
of the board does not meet standards for the application, a fire
retardant could be added to the PCM or to the board during making.
The paper on the absorption face could be the one used at the
present time or a more porous paper or a perforated paper or a
thinner paper or another type of porous film to increase the rate
of absorption.
[0099] As a general rule, during the absorption operation, the
temperature of the board has to be above the melting temperature of
the PCM but under the maximum temperature that the board or PCM can
reach without any deterioration or degradation of properties. In
the case of a paraffin absorption into gypsum wallboards, the
maximum temperature is about 95.degree. C.; over this temperature
there is a risk of deterioration of the interface gypsum-paper.
Laboratory tests have also shown that the rate of paraffin
absorption into gypsum wallboards increases when the board
temperature is increased. Another possibility is to increase the
temperature only on the absorption face to concentrate the PCM in
this part of the volume. This could be made by radiant heating, by
a quick cooling of the other side or using a hot PCM on a colder
board. The temperature of the PCM has to be above its melting point
and in many cases its viscosity is reduced while heated; this
improves the rate of absorption.
[0100] If not micro-encapsulated, the PCM must be compatible with
the material of the board. The PCM must not represent any risk for
health and has to be chemically and physically stable over a long
period. The necessary amount of PCM must be retainable by the board
material and a wetting agent could be added, if necessary. A list
of organic PCM with possible additives is given in U.S. Pat. No.
4,797,160 by Salyer. In an actual manufacturing process as
presently practiced, the PCM absorption could be performed
immediately after the boards exit or are removed from the drying
oven (their temperature being at that moment about 90.degree.
C.)
[0101] When the PCM absorption operation is completed, the face of
the board, through which the PCM has been absorbed, could remain as
is or could be covered with a protective coating or material The
surface could be covered with a paint or a varnish or a paper to
prevent losses of PCM by evaporation and by capillarity with other
materials in direct contact with the board. In the case of ceiling
tiles and gypsum wallboards impregnated using the back surface,
covering of the surface by an aluminum film could prevent heat loss
or gain by radiation from inside the wall or ceiling, could prevent
losses of the PCM, could prevent bacteriological deterioration of
the PCM and could reduce the inflammability of the impregnated
board.
[0102] In one embodiment shown in FIG. 12A, a ceiling tile or floor
panel 1 is disposed on a moving conveyor belt 2 with the surface to
be impregnated on top. The board 1 enters a spray chamber 3 inside
of which a uniform amount of liquid PCM 4 strikes the surface. The
rate of liquid sprayed is less than the rate of absorption into the
board to avoid liquid accumulation on the surface. The amount of
PCM impregnated into the board depends on the belt speed or on the
spray chamber length. For instance, consider a spray chamber 15 m
long and a spray rate of 1 L/m 2.min; to absorb 1.25 L/m 2 into
boards the belt speed has to be 0.2 m/s. A roller 11 with a
plurality of predetermined shapes 13 (or pattern 13) is positioned
at the output end, and the roller is positioned by a computer to
form continuous grooves or ridges or patterns on the tile/panel 2
in one embodiment. If the spray is used, a texture aggregate filler
mixed with said PCM, the filler can be one of: perlite, glass
microballoons, glass bubbles, phenolic microballoons, and
microspheres.
[0103] Perlite is a well-known generic term for naturally occurring
silicous rock, namely, sodium potassium aluminum silicate,
typically of volcanic origin. The distinguishing feature that sets
perlite apart from other volcanic glasses is that, when heated to a
suitable point in its softening range, perlite expands from four to
twenty times its original volume. This expansion is known to be due
to the presence of two to six percent combined water in the crude
perlite rock. When quickly heated to above 1600.degree. Fahrenheit
(871.degree. Centigrade), the crude rock pops in a manner similar
to popcorn as the combined water vaporizes and creates countless
tiny bubbles, which account for the amazing light weight and other
well-known exceptional properties of expanded perlite. This
expansion process also creates perlite's white color, and the color
of expanded perlite ranges from snowy white to grayish white.
Because perlite is a form of natural glass, it is classified as
chemically inert and has a pH of approximately 7.
[0104] A suitable and preferred aggregate for use in the coating of
the present invention is hollow glass microspheres of expanded
perlite sold under the trademark DICAPERL and manufactured by
Grefco, Inc., 3435 W. Lomita Boulevard, Torrance, Calif. 90509. The
DICAPERL expanded perlite is amorphous mineral silicate (sodium
potassium aluminum silicate of volcanic origin) containing a low
percentage (less than 1%) of crystalline silica, and this aggregate
has a variety of sphere sizes denoted by product sizes DICAPERL
HP-120, HP-220, HP-520, and HP-820.
[0105] DICAPERL expanded perlite is commonly used in the fiberglass
industry as a lightweight filler for extending resin and for
lightweight putties. Such fillers are relatively inert organic or
inorganic materials that are added to plastics resins or gel coats
for special flow characteristics, to extend volume, and to lower
the cost of a fiberglass article being produced. DICAPERL expanded
perlite belongs to a group of fillers called "lightweight fillers"
that are able to reduce densities to those approaching wood. Such
lightweight fillers are able to do this because they contain an air
void that displaces volume and lowers the bulk density. While there
are various types of lightweight fillers, they are all fragile and
can be easily broken with high shear mixing. Once the particle has
been fractured, the lower weight advantage is lost. There are
several known lightweight fillers, namely, the group consisting of
perlite, glass microballoons glass bubbles, phenolic microballoons,
Q cel microspheres, and extendospheres.
[0106] In another embodiment, to provide for textured finish that
enables high thermal interaction with air flow, the PCM can include
large and/or heavy aggregate such as river sand or portland cement,
as well as stucco-like finishes that can be shot through hopper
guns or applied using a trowel or a paint roller. The texture can
be varied by the weight and size of aggregate, the thickness of the
medium holding the aggregate, and the manner of application (hopper
gun, trowel, or roller). For example, in FIG. 12B the sprayers are
replaced by successive porous rolls 5 continuously fed with liquid
PCM 6. The texture alone may be sufficient for thermal interaction
with air flow, and the rolls 5 may additionally provide a series of
predetermined shapes 13 that form continuous grooves or ridges or
patterns on the finished tile or panel 2.
[0107] The flooding process shown in FIG. 12C is better adapted to
a small scale production. The board 1 is disposed at level and has
its surface to be impregnated on top. A grid 7 is placed on the
surface to create separate small surfaces to flood with the desired
amount of liquid PCM 8 released by hopper gun nozzles or spouts 9.
The PCM can include large and/or heavy aggregate such as river sand
or portland cement, as well as stucco-like finishes that can be
shot through hopper guns or applied using a trowel or a paint
roller. The result is a highly rugged texture that interacts with
conditioned air flow. Afterward, a template 15 containing the
desired shape may optionally be stamped on the board 1 to form
grooves or ridges or patterns on the finished tile.
[0108] In another alternative, the surface to be impregnated with
solid PCM or partially melted PCM when the board is hot or on a
cold board which is heated. If the rate of melting is lower than
the rate of absorption, no liquid accumulation will occur on the
surface.
[0109] FIG. 13A shows a field embodiment for adding the PCM
materials in the field. Referring to FIG. 13A, a sprayable textured
coating 20, shown being sprayed onto a surface 21, comprises melted
PCM 22 into which is mixed a texture aggregate filler 24, for
example perlite as described above. It shall be understood that the
scale of the coating 20 and surface 21 is greatly exaggerated, for
the sake of illustration, with respect to the spray gun 26 and
supply vessel 28. Surface 21 may be, for example, ceiling tile,
floor tile, or objects made of fiberglass, metal, masonry,
high-density foam, painted wood and other materials used on the
interior and exterior of buildings.
[0110] Referring now to the drawings, there is shown self-contained
portable pressure apparatus and hand spray gun assembly
particularly suitable for spraying a texture coating material on
floors, walls, ceilings, etc. which in FIG. 13B is shown in an
operating position. The apparatus shown in general is comprised of
a pressurized air tank or cylinder 611 releasably mounted on a
backpack carrier 612 together with a handle attachment 613
releasably fastened to the tank. A pressure control and coupling
line 614 is coupled between an outlet of the tank and an inlet of a
hand spray gun 615 having a feed hopper 616. The backpack tank
carrier 612 is positioned on the back of a user represented at 618
and supports the pressurized air tank 611 while the spray gun 615
is held in one hand with the line 614 being sufficiently long to
afford ease of movement of the spray gun. The pressurized tank 611
is a conventional high pressure air cylinder or bottle normally
filled with compressed air to a pressure of about 2,500 pounds per
square inch, the tank having an on-off control valve 620 on top
regulated by a knob 621 and also having a tapered recess around an
outlet 622 surrounded by an O-ring 623. The pressurized tank 611
complies with OSHA safety standards.
[0111] The backpack tank carrier 612 comprised of a generally
L-shaped support frame adapted for supporting the tank having a
flat base plate with an upturned retaining flange on one edge and
an upright support plate extending up from an edge of the base at
right angles thereto and opposite the retaining flange for
providing a back side for supporting the tank. A side gusset plate
is secured at the side at each corner between the base plate and
upright support plate. An auxiliary plate is secured across the
upright support plate providing a pair of side extensions beyond
the side edges of the upright support plate. A rigid shoulder strap
is affixed at one end on a side extension of the auxiliary plate to
be essentially flush with plate and extends up, out away from and
back down so as to be generally arcuate to fit over the shoulders
of the user. In turn, a rigid shoulder strap is affixed to the
other side extension of the auxiliary plate. A cushion member of a
rubber or rubberized material fits over the strap and a similar
cushion member on strap to engage the shoulders of the user for
comfort. The shoulder straps are constructed and arranged on the
frame so that when disposed on its side with the corner of the
frame on a support surface, the shoulder straps dispose the tank at
an angle of inclination with the upper end portion of the tank
substantially above the support surface and the angle and weight
distribution of the tank is such that there is no tendency to tip
over toward the top so as to damage the tank valve 620. In this way
the tank valve 620 is protected against an accidental sharp blow or
the like.
[0112] For releasably securing the tank to the carrier frame there
is shown an arcuate stationary arm 36 that is affixed at one end to
an upper portion of the upright support plate 27 and is curved to
extend partially around the tank and an arcuate movable arm 37 that
is pivotally attached to the upright support plate 27 by means of a
hinge 38 so that it will extend partially around the opposite side
and co-operate with the stationary arm 36 to secure the tank to the
carrier. A releasable buckle-type fastener is secured at the free
ends of the support arms. This fastener is conventional and is in
the form of a hook 41 on the movable arm 37 and loop and lever
member 42 on the stationary arm 36 so that when the lever is
pivoted to one side it is closed and the arms are tightly held
against the tank and when pivoted to the other side the loop is
moved out of the hook. The movable arm 37 is shown in an open
position in dashed lines at 37' in FIG. 5 allowing the tank to be
removed from the carrier.
[0113] To provide for manually carrying the backpack carrier 612
and tank 611 assembly to the point of use the handle attachment 613
is releasably mounted on an upper portion of the tank. This handle
attachment 613 has a C-clamp portion 648 in the form of relatively
wide plate bent along its length to conform to the circular
transverse cross section of the tank in a C-clamp arrangement and
further has a pair of opposed extended portions 649 and 650 through
which screw fasteners 651 extend so that it clamps firmly against
the tank. Extension 650 is elongated and terminates in a rounded
grip portion 652 covered by a cylindrical hollow cushion 653 and is
also provided with a slot 654 allowing the user to insert the
fingers into the slot and grip the cushion and grip portion 652.
The handle attachment 613 is located on a center line above the
midpoint between the top and bottom of the tank so that when the
handle is gripped, there is a counter balancing effect whereby the
lower part of the tank remains in a dependent lowermost
position.
[0114] For further releasably securing the carrier frame to the
user there is provided a belt 645 that extends through a pair of
slots in the support plate to extend around the body of the user
together with a buckle on the free ends of the belt to fasten said
free ends of the belt together.
[0115] The line pressure control and hose coupling 614 comprise a
conventional pressure regulator tank valve 661 adapted to be
releasably coupled to the valve 620 on the tank having an outlet
coupled by a length of flexible hose 662 to the inlet of a pressure
regulator 663 having a pressure indicator 64 and control knob 65. A
commercially available regulator 663 is Wilkerson No. 2019-21. A
length of flexible hose 666 is coupled to the outlet of the
pressure gauge to the inlet of an on-off air valve 667 which in
turn coupled to the inlet of the spray gun 615. Conventional brass
fittings are shown on the ends of the flexible hoses and these
fittings are attached to the tank valve 661, pressure regulator
gauge 662 and on-off valve 667 in sequence in the flow line.
[0116] The tank valve 661 is a conventional commercially available
unit and has a portion 671 that fits over the O-ring on the valve
620 and a threaded screw that releasably locks the tank valve 61 in
place on the top of the tank as shown in FIG. 1. The pressure
regulator tank valve 661 reduces the tank pressure from about 2,500
psi to 110 to 95 psi. In turn, the pressure gauge will control the
pressure from 110 psi down to 0 psi to give a full range of
pressure control for operating the spray gun or like load. The
on-off valve 667 permits the selective shutting off of the pressure
to the spray gun entirely.
[0117] The spray gun shown is conventional Pattern Piston such as
that sold by Goldblatt. The feed hopper 616 is releasably held on
the gun by a hose clamp 675 at its lower end. The feed hopper has a
handle 676 and an open upper end into which the fluent coating
material is poured. In the hand carrying of the apparatus, the
spray gun 615 and line pressure control and coupling assembly is
placed in the hopper. In one embodiment, a heater is provided to
melt the PCM materials and a mixing blade is used to mix the melted
PCM materials with aggregates to provide tall textures that provide
thermal interactions with the conditioned air flow.
[0118] The spray gun shown has an air pressure inlet, a spring
biased control trigger, a material cavity receiving material from
the feed hopper 616 by gravity flow, a rubber jacket with a hollow
beveled head is movable against a rubber washer whereby as the
trigger is pulled back, compressed air forces the material through
an aperture in the rubber washer. The gun also has a ring forming
an outlet orifice alines with the rubber washer that determines the
pattern. These things will affect the texture of the material being
sprayed: the size of the orifice, the liquid state of the material
and the air pressure.
[0119] FIG. 13C shows an exemplary PCM liquid applicator similar to
a paint roller but for dispensing PCM onto building materials. The
roller is generally designated 710 which includes a cylindrical
roller 712 having an exterior cylindrical surface 714 which is
porous for the flow of a PCM liquid to be applied to a surface
therethrough. The outer porous surface 714 is mounted over a
cylindrical core 716 which has a closure 718 at one end and an end
wall 720 at an opposite end which encloses a pressure space 722
interiorly of the porous applicator wall 714 and the porous wall
716. The roller 712 is supported for rotation on support means 723
which includes a handle portion 724 and a rotational support
portion 726. The handle portion 724 is connected through a tubular
part 728 to the rotational support portion 726 which connects
through a journal fitting 730 of the end closure 720 of the roller
712. In one embodiment three separate supply passages for the paint
732, 734 and 736 connect from a common PCM supply line 738 and pass
through an outer tubular covering 42 within the section 28 to the
section 26 and through to the fitting 30. These three separate
supply conduits connect individual supply conduits 32', 34' and 36'
inside the paint roller 12 and they have discharge openings which
discharge into a radial space between the interior cylinder 16 and
the roller transfer surface 14. This annular space 22 is thus
maintained under pressure supplied from a pump 40 which is mounted
on a paint can cover cap 42. The pump 40 takes suction through a
suction line 44 which is dipped into an ordinary paint can 46 and
which is closed by the cover fitting 42. The paint is discharge by
the pump 40 through the discharge conduit line 38 where it branches
to the conduits 32, 34 and 36 and flows through the conduits 32',
34' and 36' to the various sections of the pressure space 22
located along the length of the interior of the applicator surface
14. Paint may be returned by the build up of pressure if necessary
through a return opening 48 which connects through a radial channel
50 of the fitting 30 and connects through a return line 52 for
return to the pump. The amount of pressure which is maintained
between the interior hollow cylinder 16 and the porous surface 14
may be varied by controlling the rate of return of the paint
through the return line or by controlling the speed of operation of
the pump 40.
[0120] The pump 40 is advantageously driven by a variable speed
electric motor which is supplied with electricity through a battery
(not shown) or through a connecting port 754. The electrical wires
are transmitted through a conduit 756 up through the handle 724 and
they pass through the handle and the section 728 to a drive motor
758 for driving the roller at a controlled rotational speed. While
the motor is an electric motor having an output shaft which drives
through gears it may advantageously comprise a fluid motor which is
operated by the fluid pressure generated by the pump motor driving
the paint to the roller. The gear is carried on the inner cylinder
and rotates it along with the outer applicator surface at a rate
which is varied in accordance with the thickness of paint to be
deposited during each revolution. The handle 724 advantageously
includes an on and off button 766 for the roller drive motor and an
on and off button 768 for the pump motor 740. The control button
766 may also include a speed variation for the drive motor if
desired. In addition the handle contains a control button 770 for
distributing the paint flow from the discharge 738 of the pump 740
to each of the three separate lines. For this purpose the control
770 may be positioned in the center position at which point it has
a portion which deflects a control valve pin to open the center
conduit or it may be positioned to either the left or to the right
of the position to separately open only the control lines by
depressing valves. In addition it may be moved backwardly in an
elongated slot defined in the handle to depress all three valves at
once to permit flow through each one of them.
[0121] In one embodiment the handle 724 is provided with an end
portion forming a PCM reservoir. The reservoir is filled by
removing a cap and pouring aggregated PCM liquids into the
reservoir when it is inverted and then securing the cap back in
place by threading it onto a bottom handle portion. The handle
contains a pump and drive motor which includes a pump suction which
extends into the bottom of the reservoir into the lower portion of
the cap. In this embodiment the pump may be driven at a controlled
speed to discharge the paint through a discharge conduit at a
controlled rate for effecting the best application onto the paint
receiving surfaces. Some paint may be returned through a return
line back to the reservoir and this line may advantageously have a
control valve for regulating the amount of paint which is
returned.
[0122] As noted in Application 20100087115, phase change materials
can be encapsulated in a number of materials to contain the PCM and
prevent it from leaking out when in a liquid phase. In general, a
PCM can be any substance (or any mixture of substances) that has
the capability of absorbing or releasing thermal energy by means of
a phase change within a temperature stabilizing range. The
temperature stabilizing range can include a particular transition
temperature or a particular range of transition temperatures. A PCM
is typically capable of maintaining a temperature condition during
a time when the PCM is absorbing or releasing heat, typically as
the PCM undergoes a transition between two states (e.g., liquid and
solid states, liquid and gaseous states, solid and gaseous states,
or two solid states). Thermal energy may be stored or removed from
the PCM, and can effectively be recharged by a source of heat or
cold.
[0123] PCMs that can be used include various organic and inorganic
substances. Organic PCMs may be preferred for the embodiments
disclosed herein. Examples of phase change materials include
hydrocarbons (e.g., straight-chain alkanes or paraffinic
hydrocarbons, branched-chain alkanes, unsaturated hydrocarbons,
halogenated hydrocarbons, and alicyclic hydrocarbons), hydrated
salts (e.g., calcium chloride hexahydrate, calcium bromide
hexahydrate, magnesium nitrate hexahydrate, lithium nitrate
trihydrate, potassium fluoride tetrahydrate, ammonium alum,
magnesium chloride hexahydrate, sodium carbonate decahydrate,
disodium phosphate dodecahydrate, sodium sulfate decahydrate, and
sodium acetate trihydrate), waxes, oils, water, fatty acids, fatty
acid esters, dibasic acids, dibasic esters, 1-halides, primary
alcohols, secondary alcohols, tertiary alcohols, aromatic
compounds, clathrates, semi-clathrates, gas clathrates, anhydrides
(e.g., stearic anhydride), ethylene carbonate, methyl esters,
polyhydric alcohols (e.g., 2,2-dimethyl-1,3-propanediol,
2-hydroxymethyl-2-methyl-1,3-propanediol, ethylene glycol,
polyethylene glycol, pentaerythritol, dipentaerythritol,
pentaglycerine, tetramethylol ethane, neopentyl glycol,
tetramethylol propane, 2-amino-2-methyl-1,3-propanediol,
monoaminopentaerythritol, diaminopentaerythritol, and
tris(hydroxymethyl)acetic acid), sugar alcohols (erythritol,
D-mannitol, galactitol, xylitol, D-sorbitol), polymers (e.g.,
polyethylene, polyethylene glycol, polyethylene oxide,
polypropylene, polypropylene glycol, polytetramethylene glycol,
polypropylene malonate, polyneopentyl glycol sebacate, polypentane
glutarate, polyvinyl myristate, polyvinyl stearate, polyvinyl
laurate, polyhexadecyl methacrylate, polyoctadecyl methacrylate,
polyesters produced by polycondensation of glycols (or their
derivatives) with diacids (or their derivatives), and copolymers,
such as polyacrylate or poly(meth)acrylate with alkyl hydrocarbon
side chain or with polyethylene glycol side chain and copolymers
including polyethylene, polyethylene glycol, polyethylene oxide,
polypropylene, polypropylene glycol, or polytetramethylene glycol),
metals, and mixtures thereof.
[0124] The selection of a PCM is typically dependent upon the
transition temperature that is desired for a particular application
that is going to include the PCM. The transition temperature is the
temperature or range of temperatures at which the PCM experiences a
phase change from solid to liquid or liquid to solid. For example,
a PCM having a transition temperature near room temperature or
normal body temperature can be desirable for clothing applications.
A phase change material according to some embodiments of the
invention can have a transition temperature in the range of about
-5.degree. C. to about 125.degree. C. In one embodiment, the
transition temperature is about 6.degree. C. to about 37.degree. C.
In another embodiment, the transition temperature is about
15.degree. C. to about 30.degree. C. In another embodiment, the PCM
has a transition temperature of about 30.degree. C. to about
45.degree. C.
[0125] Paraffinic PCMs may be a paraffinic hydrocarbons, that is,
hydrocarbons represented by the formula CnHn+2, where n can range
from about 10 to about 44 carbon atoms. PCMs useful in the
invention include paraffinic hydrocarbons having 13 to 28 carbon
atoms. For example, the melting point of a homologous series of
paraffin hydrocarbons is directly related to the number of carbon
atoms as shown in the following table:
TABLE-US-00001 Compound Name # Carbon Atoms Melting Point (.degree.
C.) n-Octacosane 28 61.4 n-Heptacosane 27 59.0 n-Hexacosane 26 56.4
n-Pentacosane 25 53.7 n-Tetracosane 24 50.9 n-Tricosane 23 47.6
n-Docosane 22 44.4 n-Heneicosane 21 40.5 n-Eicosane 20 36.8
n-Nonadecane 19 32.1 n-Octadecane 18 28.2 n-Heptadecane 17 22.0
n-Hexadecane 16 18.2 n-Pentadecane 15 10.0 n-Tetradecane 14 5.9
n-Tridecane 13 -5.5
[0126] Methyl ester PCMs may be any methyl ester that has the
capability of absorbing or releasing thermal energy to reduce or
eliminate heat flow within a temperature stabilizing range. In one
embodiment, the methyl ester may be methyl palmitate. Examples of
other methyl esters include methyl formate,methyl esters of fatty
acids such as methyl caprylate, methyl caprate, methyl laurate,
methyl myristate, methyl palmitate, methyl stearate, methyl
arachidate, methyl behenate, methyl lignocerate and fatty acids
such as caproic acid, caprylic acid, lauric acid, myristic acid,
palmitic acid, stearic acid, arachidic acid, behenic acid,
lignoceric acid and cerotic acid; and fatty acid alcohols such as
capryl alcohol, lauryl alcohol, myristyl alcohol, cetyl alcohol,
stearyl alcohol, arachidyl alcohol, behenyl alcohol, lignoceryl
alcohol, ceryl alcohol, montanyl alcohol, myricyl alcohol, and
geddyl alcohol.
[0127] Substantially any PCM (commonly a hydrophobic PCMs) which
can be dispersed in water and microencapsulated by the technology
referenced herein and may be useful in the present
microencapsulated PCM. Alternately, two or more different PCMs can
be used to address particular temperature ranges and such materials
can be mixed. PCMs are commercially available from PCM Energy P.
Ltd, Mumbai, India, Entropy Solutions Inc., Minneapolis, Minn., and
Renewable Alternatives, Columbia, Mo.
[0128] Encapsulating a PCM that has a boiling point of about
230.degree. C. to about 420.degree. C., preferably about
280.degree. C. to about 400.degree. C., and more preferably about
300.degree. C. to about 390.degree. C. provides enhanced flame
resistance. The PCM may be a synthetic beeswax, a non-halogenated
PCM, or any currently existing or later developed PCM that has a
boiling point within these temperature ranges. In one embodiment,
the PCM is a synthetic beeswax (a derivative mixture of fatty acid
esters) having a melting point of 28.degree. C. and a boiling point
greater than 300.degree. C. In another embodiment, the microcapsule
additionally has a flame retardant applied to the microcapsule wall
as discussed in more detail below.
[0129] Any of a variety of processes known in the art may be used
to microencapsulate PCMs in accordance with the present invention.
Microcapsule production may be achieved by physical methods such as
spray drying or by centrifugal and fluidized beds.
[0130] The microencapsulated material may be provided using any
suitable capsule chemistry. Chemical techniques may be used, such
as dispersing droplets of molten PCM in an aqueous solution and to
form walls around the droplets using simple or complex
coacervation, interfacial polymerization and in situ polymerization
all of which are well known in the art. For example, methods are
well known in the art to form gelatin capsules by coacervation,
polyurethane or polyurea capsules by interfacial polymerization,
and urea-formaldehyde, urea-resorcinol-formaldehyde, and melamine
formaldehyde capsules by in situ polymerization. U.S. Pat. No.
6,619,049, herein incorporated by reference, discloses a method for
microencapsulating a PCM in a melamine formaldehyde resin.
[0131] The ceiling material may comprise a polyacrylate, as
described in, for instance, U.S. Pat. No. 4,552,811. Gelatin or
gelatin-containing microcapsule materials are well known. The
teachings of the phase separation processes, or coacervation
processes, are described in U.S. Pat. Nos. 2,800,457 and 2,800,458
and gel-coated capsules, as purportedly described in U.S. Pat. No.
6,099,894 further may be employed in connection with the
invention.
[0132] Interfacial polymerization is a process wherein a
microcapsule wall of a polyamide, an epoxy resin, a polyurethane, a
polyurea or the like is formed at an interface between two phases.
U.S. Pat. No. 4,622,267 discloses an interfacial polymerization
technique for preparation of microcapsules. The core material is
initially dissolved in a solvent and an aliphatic diisocyanate
soluble in the solvent mixture is added. Subsequently, a nonsolvent
for the aliphatic diisocyanate is added until the turbidity point
is just barely reached. This organic phase is then emulsified in an
aqueous solution, and a reactive amine is added to the aqueous
phase. The amine diffuses to the interface, where it reacts with
the diisocyanate to form polymeric polyurethane shells. A similar
technique, used to encapsulate salts which are sparingly soluble in
water in polyurethane shells, is disclosed in U.S. Pat. No.
4,547,429.
[0133] U.S. Pat. No. 3,516,941 teaches polymerization reactions in
which the material to be encapsulated, or core material, is
dissolved in an organic, hydrophobic oil phase which is dispersed
in an aqueous phase. The aqueous phase has dissolved materials
forming aminoplast resin which upon polymerization form the wall of
the microcapsule. A dispersion of fine oil droplets is prepared
using high shear agitation. Addition of an acid catalyst initiates
the polycondensation forming the aminoplast resin within the
aqueous phase, resulting in the formation of an aminoplast polymer,
which is insoluble in both phases. As the polymerization advances,
the aminoplast polymer separates from the aqueous phase and
deposits on the surface of the dispersed droplets of the oil phase
to form a capsule wall at the interface of the two phases, thus
encapsulating the core material. This process produces the
microcapsules. Polymerizations that involve amines and aldehydes
are known as aminoplast encapsulations.
[0134] Urea-formaldehyde (UF), urea-resorcinol-formaldehyde (URF),
urea-melamine-formaldehyde (UMF), and melamine-formaldehyde (MF)
capsule formations proceed in a like manner. In interfacial
polymerization, the materials to form the capsule wall are in
separate phases, one in an aqueous phase and the other in a fill
phase. Polymerization occurs at the phase boundary. Thus, a
polymeric capsule shell wall forms at the interface of the two
phases thereby encapsulating the core material. Wall formation of
polyester, polyamide, and polyurea capsules proceeds via
interfacial polymerization.
[0135] Processes of microencapsulation that involve the
polymerization of urea and formaldehyde, monomeric or low molecular
weight polymers of dimethylol urea or methylated dimethylol urea,
melamine and formaldehyde, monomeric or low molecular weight
polymers of methylol melamine or methylated methylol melamine are
taught in U.S. Pat. No. 4,552,811. These materials are dispersed in
an aqueous vehicle and the reaction is conducted in the presence of
acrylic acid-alkyl acrylate copolymers. Preferably, the wall
forming material is free of carboxylic acid anhydride or limited so
as not to exceed 0.5 weight percent of the building material.
[0136] A method of encapsulating by in situ polymerization,
including a reaction between melamine and formaldehyde or
polycondensation of monomeric or low molecular weight polymers of
methylol melamine or etherified methylol melamine in an aqueous
vehicle conducted in the presence of negatively-charged,
carboxyl-substituted linear aliphatic hydrocarbon polyelectrolyte
material dissolved in the vehicle is disclosed in U.S. Pat. No.
4,100,103.
[0137] In one embodiment, the building material for encapsulating
the PCM contains a melamine-formaldehyde resin. In an alternate
embodiment, the microcapsule may be a dual walled capsule. Dual
wall capsules, such as first wall-second wall structures of an
acrylic polymer and an urea-resorcinal-gluteraldehyde (URG), an
acrylic polymer and an urea-resorcinal-formaldehyde (URF), a
melamine-formaldehyde and a URF, a melamine-formaldehyde and a URG,
or a URF and a melamine-formaldehyde, respectively, as disclosed in
U.S. Published Patent Application 2006/0063001, herein incorporated
by reference.
[0138] The microcapsules will typically have a relatively high
payload of PCM of about 60% to 85%. In one embodiment, the phase
change material is present at about 70% to 80% by weight. The PCM
may be one or a combination of the PCMs described above.
[0139] The size of the microcapsules typically range from about
0.01 to 100 microns and more typically from about 2 to 50 microns.
The capsule size selected will depend on the application in which
the microencapsulated PCM is used. For example, they may be used as
the thermal transfer medium in a heat transfer fluid for use in
lasers, supercomputers and other applications requiring high
thermal transfer efficiencies. They also may be coated on fibers or
incorporated into fibers to prepare insulative fabrics. They may be
added to plastics or resins such as polypropylene and acrylics and
spun into fibers or extruded into filaments, beads or pellets
useful in thermal transfer applications such as insulative apparel
such as clothes, shoes, boots, etc., building insulation for use in
ceilings, floors, etc. For use in heat transfer fluids, the capsule
size may range from about 1 to 100 microns and more typically from
about 2 to 40 microns. For use in fibers, yarns, or textile the
capsule size may be about 1 to 15 microns or about 2 to 10 microns.
For other applications, the capsule size range is about 0.5 microns
to about 10 microns.
[0140] These microencapsulated PCM may be made of different tile
thicknesses. Typically the tile material should be thick enough to
contain the PCM while in its liquid phase. The thickness may be
about 0.1 to about 0.9 microns. In one embodiment, the tile may be
about 0.2 to about 0.6 microns thick with a nominal (mean)
thickness of about 0.4 microns. The capsule walls should be
sufficiently thick to avoid rupture when processed into other
materials or products, such as those discussed above.
[0141] Those skilled in the art will appreciate that the capsule
size and wall thickness may be varied by many known methods, for
instance, adjusting the amount of mixing energy applied to the
materials immediately before wall formation commences. Capsule wall
thickness is also dependent upon many variables, including the
speed of the mixing unit used in the encapsulation process.
[0142] Other microencapsulation processes known in the art or
otherwise found to be suitable for use with the invention may be
employed. In one embodiment, a plurality of microencapsulated PCMs
having the same or different encapsulation may be contained in
"macrocapsules" as disclosed in U.S. Pat. No. 6,703,127 and No.
5,415,222, herein incorporated by reference in their entirety.
Macrocapsules may provide a thermal energy storage composition that
more efficiently absorbs or releases thermal energy during a
heating or a cooling process than individual microencapsulated
PCMs.
[0143] Various flame retardants may be used to enhance flame
resistance of an encapsulated phase change material. In one
embodiment, the flame retardant may contain one or more of boric
acid, borates, ammonium polyphosphates, sodium carbonate, sodium
silicate, aluminum hydroxide, magnesium hydroxide, antimony
trioxide, various hydrates, tetrakis(hydroxymethyl)phosphonium
salts, halocarbons, including chlorendic acid derivates,
halogenated phosphorus compounds including tri-o-cresyl phosphate,
tris(2,3-dibromopropyl)phosphate (TRIS),
bis(2,3-dibromopropyl)phosphate, tris(1-aziridinyl)-phosphine oxide
(TEPA), and others.
[0144] The flame retardant may be applied to the wall material as a
solution, dispersion, a suspension, or a colloid that forms a
coating on the wall material to provide flame resistant
characteristics to the microencapsulated PCM. The flame retardant
may be present in an amount to make about a 2% to about a 50% flame
retardant solution, dispersion, suspension, or colloid. In another
embodiment, the flame retardant may be present in an amount to make
about a 5% to about a 30% flame retardant solution, dispersion,
suspension, or colloid. Any solvent may be used dissolve, mix, or
suspend the flame retardant without decomposing or reacting with
the flame retardant, the wall material, or any other solvents
present. The solvent may be water, an aliphatic or aromatic
solvent, and/or an alcohol. The application of the flame retardant
as a solution, dispersion, suspension, or colloid (the flame
retardant medium) is advantageous because it provides a relatively
simple manufacturing process as seen in the Examples below and
described in more detail in the Method section below.
[0145] A method for making a microencapsulated phase change
material having flame resistance may include providing an
encapsulated phase change material and applying a composition
containing a flame retardant to the encapsulated phase change
material. The flame retardant composition may contain any of the
flame retardants described above or a combination thereof and may
be present in a solution, dispersion, suspension, or colloid in the
concentrations given above.
[0146] The flame retardant composition may be applied by spraying,
pan coating, or by using a fluidized bed, industrial blender, or
other various types of mixers and/or blenders. In another
embodiment, the encapsulated PCMs may be suspended in a composition
containing the flame retardant to allow a coating to form on the
outer surface of the microcapsule wall. The composition may be a
solution, dispersion, suspension, or colloid, as described above.
The encapsulated PCMs way be added to the composition as a powder,
wet cake, or as a slurry. A slurry may be advantageous in mixing
more quickly with the composition.
[0147] The flame retardant is applied in an amount of about 5% to
about 30% flame retardant by weight of the coated microcapsule.
[0148] To vary the percent by weight of the flame retardant coating
on the microencapsulated PCMS the amount of time the
microencapsulated PCMs remains in or is coated with the flame
retardant medium may be altered. Theoretically, there is likely an
amount of time that even if exceeded will not deposit more flame
retardant on the microcapsules as an equilibrium state may be
achieved between the flame retardant in the flame retardant medium
and the amount of flame retardant deposited on the microcapsules.
Alternately, the amount or concentration of flame retardant in the
flame retardant medium may also affect the amount of flame
retardant deposited as well as the time it takes to deposit the
desired amount of flame retardant. One skilled in the art will also
recognize that other factors may affect the time and amount of
flame retardant deposited such as temperature, pressure, agitation
of the medium, etc.
[0149] After the flame retardant coating is applied the coated
microcapsules are removed from the composition and are dried. The
removal of the coated encapsulated PCMs from the solution,
dispersion, suspension, or colloid may be by any conventional
process, such as filtering or centrifuging. The coated encapsulated
PCMs may be dried thereafter using any convention process, such as
air drying, oven drying, spray drying, or fluid bed drying. The
coated microcapsules may be dried to about a 5% moisture content or
less. The microcapsules may have a moisture content of about 1% to
about 2%. Alternately, rather than drying the coated encapsulated
PCMS, the microcapsules may be contained as a wet cake. The wet
cake may have a moisture content of about 30%.
[0150] The coated encapsulated PCMs may have a variety of uses
because many industries may be able to take advantage of the coated
capsules flame resistance. The flame resistant encapsulated PCMs
may be incorporated into a number of articles such as textile
materials, building materials, packaging materials, and electronic
devices. Textile materials may have the coated encapsulated PCMs
incorporated into the fiber and/or fabrics they are made of The
textile material may be used to make clothing items, window
treatments, and medical wraps to provide flame resistance and the
thermal characteristics of the PCM. Building materials may include
the flame resistant encapsulated PCMs on or in them, such as
insulation, lumber, roofing materials, and floor and ceiling tiles.
Packaging materials may include food serving trays, bubble wrap,
packaging peanuts, labels, cardboard, paper, and insulated
containers. Electronic devices may include the coated encapsulated
PCMs to remove heat from electrical components that may be damaged
by heat, such as computers, televisions, or any other machine with
electronic components. The coated encapsulated PCMs may also be
incorporated into a binder to provide a coating useful in many
applications, such as paints, sprays, etc. that may even be useful
in applying the coated encapsulated PCMs to the items described
above.
[0151] The present invention, in various embodiments, includes
components, methods, processes, systems and/or apparatus
substantially as depicted and described herein, including various
embodiments, subcombinations, and subsets thereof. Those of skill
in the art will understand how to make and use the present
invention after understanding the present disclosure. The present
invention, in various embodiments, includes providing devices and
processes in the absence of items not depicted and/or described
herein or in various embodiments hereof, including in the absence
of such items as may have been used in previous devices or
processes, e.g., for improving performance, achieving ease and\or
reducing cost of implementation.
[0152] The foregoing discussion of the invention has been presented
for purposes of illustration and description. The foregoing is not
intended to limit the invention to the form or forms disclosed
herein. In the foregoing Detailed Description for example, various
features of the invention are grouped together in one or more
embodiments for the purpose of streamlining the disclosure. This
method of disclosure is not to be interpreted as reflecting an
intention that the claimed invention requires more features than
are expressly recited in each claim. Rather, as the following
claims reflect, inventive aspects lie in less than all features of
a single foregoing disclosed embodiment. Thus, the following claims
are hereby incorporated into this Detailed Description, with each
claim standing on its own as a separate preferred embodiment of the
invention.
[0153] Moreover, though the description of the invention has
included description of one or more embodiments and certain
variations and modifications, other variations and modifications
are within the scope of the invention, e.g., as may be within the
skill and knowledge of those in the art, after understanding the
present disclosure. It is intended to obtain rights which include
alternative embodiments to the extent permitted, including
alternate, interchangeable and/or equivalent structures, functions,
ranges or steps to those claimed, whether or not such alternate,
interchangeable and/or equivalent structures, functions, ranges or
steps are disclosed herein, and without intending to publicly
dedicate any patentable subject matter.
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