U.S. patent application number 12/641231 was filed with the patent office on 2010-06-24 for methods of modifying surface coverings to embed conduits therein.
Invention is credited to Michael S. Hulen.
Application Number | 20100154216 12/641231 |
Document ID | / |
Family ID | 42264016 |
Filed Date | 2010-06-24 |
United States Patent
Application |
20100154216 |
Kind Code |
A1 |
Hulen; Michael S. |
June 24, 2010 |
Methods of Modifying Surface Coverings to Embed Conduits
Therein
Abstract
Methods of modifying surface coverings to embed conduits therein
to collect solar heat energy including grinding away a portion of
the surface covering, installing a network of conduits in the
recess and filling the recess to cover the conduits with a material
capable of transferring heat from solar radiation to the conduits
and a method for modifying a surface covering to embed conduits
therein to collect solar heat energy including softening the
surface covering, forming a channel in the softened surface
covering, pressing a conduit into the channel and filling the
channel with thermal conductive material to cover the conduit.
Inventors: |
Hulen; Michael S.; (Acton,
MA) |
Correspondence
Address: |
EPSTEIN & GERKEN
1901 RESEARCH BOULEVARD, SUITE 340
ROCKVILLE
MD
20850
US
|
Family ID: |
42264016 |
Appl. No.: |
12/641231 |
Filed: |
December 17, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61138143 |
Dec 17, 2008 |
|
|
|
Current U.S.
Class: |
29/890.033 |
Current CPC
Class: |
F24S 20/64 20180501;
E01C 11/26 20130101; F24D 2220/006 20130101; F24S 90/00 20180501;
Y02B 10/20 20130101; Y02E 10/40 20130101; Y02B 30/00 20130101; F24S
20/62 20180501; Y02E 10/44 20130101; Y10T 29/49355 20150115; F24D
3/12 20130101 |
Class at
Publication: |
29/890.033 |
International
Class: |
B21D 53/06 20060101
B21D053/06 |
Claims
1. A method for modifying a surface covering to embed conduits
therein to collect solar heat energy comprising the steps of
grinding away a portion of the surface covering to form a recess
therein; installing a network of conduits for carrying heated fluid
in the recess; and filling the recess to cover the conduits with a
material capable of transferring heat from solar radiation to the
conduits to heat the fluid.
2. The method for modifying a surface covering to embed conduits as
recited in claim 1 wherein the surface covering is pavement and
said filling step includes filling the recess with ground
pavement.
3. A method for modifying a surface covering to embed conduits
therein to collect solar heat energy comprising the steps of
forming a channel in the softened surface covering; pressing a
conduit into the channel; and filling the channel with thermal
conductive material to cover the conduit.
4. The method for modifying a surface covering to embed conduits as
recited in claim 3 wherein the thermal conductive material is
obtained from the surface covering.
5. The method for modifying a surface covering to embed conduits
therein as recited in claim 4 wherein said softening step includes
heating the surface covering.
6. The method for modifying a surface covering to embed conduits
therein as recited in claim 5 wherein said softening step, said
step of forming a channel, said pressing step and said filling step
are all accomplished by a piece of equipment moved along the
surface.
Description
CROSS-REFERENCE TO RELATED PATENT APPLICATION
[0001] This application claims priority from prior provisional
patent application Ser. No. 61/138,143 filed Dec. 17, 2008, the
entire disclosure of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention pertains to obtaining and using
power/energy from man-made structures including manufactured
(paved) surfaces and, more particularly, modifying pre-existing
surface coverings to create power/energy in the form of heat
obtained from solar radiation for use in the operation of energy
conversion equipment, such as chillers, hot water supplies, heat
pumps, organic Rankine cycle engines for mechanically generating
electricity, water purification and distillation for buildings
and/or other facilities.
[0004] 2. Brief Discussion of the Related Art
[0005] Surfaces and structures are heated by solar radiation during
the course of a typical sunny day. A typical asphalt or concrete
surface has good heat-absorbing properties, and the heat energy
from such structures is normally wasted and not utilized to its
potential. Greater use of solar energy is an environmental friendly
way of meeting increasing energy needs. In recent years, it has
become increasingly evident that fossil fuels used to generate
energy are finite and that their use is harmful to the environment.
Large paved surfaces increase surface temperatures. The National
Oceanic and Atmospheric Administration's National Geophysical Data
Center relative to highways, streets, buildings, parking lots and
other solid structures, notes that the total paved surface area of
the 48 contiguous states of the United States of America and the
District of Columbia is approximately 43,480 square miles (112,610
km.sup.2). This same study further describes that 1.05% of the
United States of America land area is constructed, impervious
surface (83,337 km.sup.2) and 0.43% of the world's land surface
(579,703 km.sup.2) is constructed, impervious surface. China has
more impervious surface area than any other country (87,182
km.sup.2) but has only 67 m.sup.2 of impervious surface area per
person, compared to 297 m.sup.2 per person in the United States of
America. Asphalt, concrete, bituminous roofs and other hard-paved
surfaces absorb heat making it unpleasant to walk on a sidewalk in
hot weather and increasing the strain on the air conditioning
systems of buildings. Since hot air rises, the hot air traps
airborne pollutants, such as auto exhaust, close to the ground
adding to complications for pedestrians. The Portland Cement
Association estimates that the "heat island effect" of concentrated
areas of paved surfaces impervious to water increases the
temperature of the paved areas by average of three to eight
degrees. The most extreme increases take place in heavily paved
areas, areas without shade, and areas paved with materials that
don't reflect substantial light, such as asphalt. The heat island
effect occurs in both small-town and urban commercial areas.
[0006] The organic Rankine cycle engine uses an organic, high
molecular mass fluid with a liquid-vapor phase change, or boiling
point, occurring at a lower temperature than the water-steam phase
change. Accordingly, Rankine cycle heat recovery can be obtained
from lower temperature sources such as industrial waste heat,
geothermal heat, solar ponds and the like. Typically, the lower
temperature heat is converted into useful work that can itself be
converted into electricity.
[0007] Waste heat recovery is the most important development field
for the organic Rankine cycle engine, as well as for
absorption/adsorption chillers. Waste heat can be applied to heat
and power plants (for example a small scale cogeneration plant for
a domestic water heater) and also can be applied to industrial and
farming processes such as organic products fermentation, hot
exhausts from ovens or furnaces, flue gas condensation, exhaust
gases from vehicles, inter-cooling of a compressor, and condenser
of a power cycle.
[0008] As identified by the United States Environmental Protection
Agency, developing urban areas modify their landscape. For example,
solid and impermeable buildings, roads, and other infrastructure
replace permeable and moist fields and vegetation. These changes
cause urban regions to become warmer than their rural surroundings,
forming an "island" of higher temperatures in the landscape. These
heat islands occur on the surface and in the atmosphere. On a hot,
sunny summer day, the sun can heat dry, exposed urban surfaces,
such as roofs and pavement, to temperatures 50-90.degree. F.
(27-50.degree. C.) hotter than the ambient air, while shaded or
moist surfaces--often in more rural surroundings--remain closely
aligned to ambient temperatures. Surface urban heat islands are
typically present day and night, but tend to be strongest during
the day when the sun is shining. The EPA states that these elevated
temperatures from urban heat islands, particularly during the
summer, can affect a community's environment and quality of life;
the majority negative. These impacts include:
(1) Increased energy demand for cooling. Research shows that
electricity demand for cooling increases 1.5-2.0% for every
1.degree. F. (0.6.degree. C.) increase in air temperature, starting
from 68 to 77.degree. F. (20 to 25.degree. C.), suggesting that
5-10% of community-wide demand for electricity is used to
compensate for the heat island effect. Peak electricity demand,
instigated by the urban heat island, inevitably occurs on hot
summer weekday afternoons when offices and homes are running
cooling systems, lights, and appliances. The resulting demand for
cooling can overload systems and require a utility to institute
controlled, rolling brownouts or blackouts to avoid power outages.
(2) Elevated Emissions of Air Pollutants and Greenhouse Gases.
Increasing energy demand generally results in greater emissions of
air pollutants and greenhouse gas emissions from power plants.
Higher air temperatures also promote the formation of ground-level
ozone. (3) Compromised Human Health and Comfort. Increased daytime
temperatures, reduced nighttime cooling, and higher air pollution
levels associated with urban heat islands can affect human health
by contributing to respiratory difficulties, heat exhaustion,
non-fatal heat stroke, and heat-related mortality. Excessive heat
events, or abrupt and dramatic temperature increases, are
particularly dangerous and can result in above-average rates of
mortality. The Centers for Disease Control and Prevention estimates
that from 1979-2003, excessive heat exposure contributed to more
than 8,000 premature deaths in the United States. This figure
exceeds the number of mortalities resulting from hurricanes,
lightning, tornadoes, floods, and earthquakes combined. (4)
Impaired Water Quality. High pavement and rooftop surface
temperatures can heat storm-water runoff. Tests have shown that
pavements that are 100.degree. F. (38.degree. C.) can elevate
initial rainwater temperature from roughly 70.degree. F.
(21.degree. C.) to over 95.degree. F. (35.degree. C.). This heated
storm-water generally becomes runoff, which drains into storm
sewers and raises water temperatures as it is released into
streams, rivers, ponds, and lakes. Water temperature affects all
aspects of aquatic life, especially the metabolism and reproduction
of many aquatic species. Rapid temperature changes in aquatic
ecosystems resulting from warm storm-water runoff can be
particularly stressful, even fatal, to aquatic life.
[0009] There are four current strategies to mitigate the urban heat
island effect:
[0010] (1) Increasing tree and vegetative cover over the general
landscape;
[0011] (2) Creating rooftop gardens;
[0012] (3) Installing reflective roofs; and
[0013] (4) Employing cool pavement technologies (aggregate
make-up).
Heat island mitigation is part of a community's energy, air
quality, water, or sustainability effort. These activities may
range from voluntary initiatives to policy actions, such as
requiring cool roofs via building codes. Most mitigation activities
have multiple benefits, including cleaner air, improved human
health and comfort, reduced energy costs and lower greenhouse gas
emissions.
[0014] As an alternative to powering vehicles using the internal
combustion engine, designers have experimented with batteries, fuel
cells, and solar panels. These experiments have been motivated, in
large part, by a concern that gases emitted by internal combustion
engines could harm humans by adversely affecting their environment.
Motivated by these concerns, lawmakers have passed laws governing
vehicle emissions. Accordingly, there is an ongoing need for
sources of power that can supplement or replace the internal
combustion engine as a source of power for vehicles. For similar
reasons, there is a need for alternative stationary sources of
power that reduce harmful environmental effects associated with the
combustion of fossil fuels.
[0015] With a growing concern over global climate change,
scientists, lawmakers, and entrepreneurs are all seeking solutions.
At the forefront of this debate are new sources of power. These
could provide an alternative to fossil fuels, which release harmful
greenhouse gases.
[0016] Similarly, in addition to clean energy sources, it is
important not to overlook methods to reduce the effects of global
warming. Paving over vegetation allows more heat to be absorbed by
the Earth's surface, and later reradiated into the atmosphere. This
is particularly true in areas with heavy populations, roads and
travel, where the necessity for paving is largest. This gives way
to the Urban Heat Island effect, which has increased the needs of
air conditioning in cities like Los Angles by over 40% during the
summer months.
SUMMARY OF THE INVENTION
[0017] Systems utilizing modified surface coverings formed in
accordance with the present invention use the heat absorbed by
surfaces from incident solar radiation to produce energy in various
forms. The systems can use embedded thermally conductive materials
or fluid carrying pipes/conduits in pavement as a structure to
transfer heat for multiple uses. A heated fluid will first be moved
to a heat exchanger. The heat produced can be used for hot water
for hotels, laundromats, car washes, pre-heating of boilers, or
chemical/industrial processes to name a few. The systems can also
produce electrical power through a low temperature generator such
as one powered by an organic Rankine cycle engine. Heat from the
systems can drive an absorptive or adsorptive chiller to produce an
air conditioning or cooling system. The systems can be used in
conjunction with or in series with another source, such as a
Concentrated Solar Power system, to produce higher temperatures for
more efficient power generation. Designs to improve efficiencies of
the system include the use of thermally conductive roadway
aggregates, low emissivity coatings, and use of guardrails, bridges
and other thermally conductive structures as a heat source or heat
transfer method. The system heat source can be used for
pasteurization, distillation and the like therefore permitting use
for water purification.
[0018] The system can use the aggregate itself as the conductive
material instead of another thermally conductive material that
would not normally be part of the HMA (hot mix asphalt). If
thermally conductive materials are not available locally, they can
be purchased and transported from non-local sources. A conductive
layer can be put down within the surface to reduce the costs of
what may be a more expensive aggregate material. This serves to
increase the heat travel to essential regions for practical
conversion. The heat collected from such systems can be used to run
a thermal cycle engine (e.g., an organic Rankine cycle engine), a
heat pump, or a chiller. The heat energy is used to heat a fluid
such as water or refrigerant that is used in such equipment. This
provides a means of converting raw heat into more tangible or
useful applications. A network of pipes/conduits can lead from the
source (manufactured surface covering, such as a paved surface or
structure) to the drain (energy conversion unit or heat exchanger).
The pipes/conduits can be installed in a number of ways and can be
made of various materials and geometries. Regardless of how they
are installed, the commonality is the intention of removing heat
from the pipes/conduits. The system can be used in conjunction with
other energy sources, namely geothermal, photovoltaic, and biofuel.
Additional uses include the use of these systems as a means to
purify, decontaminate, desalinate, and clean water. Heat can be
derived from buildings and roadway structures.
[0019] A low temperature source such as geothermal, flat plate or
paved surface, (roadway power system) can have its temperatures
bolstered by a supplementary heating source. This source could be
solar driven, e.g. concentrated solar power (CSP), parabolic, dish
or a combustion engine, using gas, oil, or another incendiary
source. These elevated temperatures allow use for agriculture,
water purification and desalinization, biofuels, hydrogen
generation and increased efficiencies with existing methods of
energy conversion.
[0020] When using the system to generate electricity, it will
relieve part of the dependency on `dirty` power by bringing a new
source of `green` electricity generation. It will also help reduce
loads on the electrical transmission systems since it will act as
distributed generation on-site.
[0021] One aspect of the present invention is to provide a method
for modifying or retrofitting an existing surface covering to embed
conduits therein providing a heat recovery structure.
[0022] In another aspect, the method of the present invention
permits modification or retrofitting of a man-made covering on the
earth's surface to have fluid carrying conduits embedded therein
with a purpose of delivering solar heated fluid to an energy
conversion device. The covering can be any existing surface such as
a paved surface, a roadway, a road shoulder, a parking lot, a
sidewalk, a path, a track, a racetrack, a sports field, a roadway
divider, a railroad track, a patio, a roof, shingle or siding for
buildings, tarmac, and the like.
[0023] In another aspect, the present invention permits the use of
existing structures and surface coverings for collection by
modifying or retrofitting such structures and surface coverings,
particularly pavement and synthetic turf by embedding a conduit
network therein to collect solar heat energy.
[0024] A method according to the present invention for modifying a
surface covering to embed conduits therein to collect solar heat
energy includes the steps of grinding away a portion of the surface
covering to form a recess therein, installing a network of conduits
for carrying heated fluid in the recess and filling the recess to
cover the conduits with a material capable of transferring heat
from solar radiation to the conduits to heat the fluids.
[0025] The present invention also relates to a method for modifying
a surface covering to embed conduits therein to collect solar heat
energy including the steps of softening the surface covering,
forming a channel in the softened surface covering, passing a
conduit into the channel and filling the channel with thermal
conductive material to cover the conduit.
[0026] Various aspects, advantages and benefits of the present
invention will become apparent from the following description taken
in conjunction with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] FIG. 1 is a perspective view of a surface covering, with
parts cut away, with a network of conduits disposed in the recess
in accordance with the present invention.
[0028] FIG. 2 is a schematic representation of a device for
removing a top layer of a surface covering by grinding.
[0029] FIG. 3 is a schematic drawing of a piece of equipment for
heating a surface covering forming a channel in the surface
covering, passing a conduit into the channel and filling the
channel to cover the conduit.
[0030] FIG. 4 is a schematic representation of the shape of wheels
for pressing the conduit into the channel.
[0031] FIGS. 5 and 6 are sectional views of surface coverings after
modification or retrofitting in accordance with the method of the
present invention.
[0032] FIG. 7 is a schematic drawing showing conduits being placed
in channels formed in a surface covering in accordance with the
present invention.
[0033] FIG. 8 is a sectional schematic drawing of conduits placed
in channels in a surface covering with a top layer covering the
conduits and the high conductive layer at which the conduits are
placed.
[0034] FIGS. 9 and 10 are schematic drawings of a surface covering
having channels formed in the underside thereof with conduits
placed in the channels.
[0035] FIG. 11 is a schematic drawing showing conduits embedded in
a surface covering after modifying or retrofitting of the surface
covering.
[0036] FIG. 12 is a schematic drawing showing a guardrail with a
base thermally coupled with a roadway.
[0037] FIG. 12A is a sectional schematic drawing of a guardrail
having a thermal insulated outer coating to retain heat.
[0038] FIGS. 13, 14 and 15 are schematic/block diagrams of a system
utilizing a surface covering retrofitted or modified in accordance
with the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0039] FIG. 1 is a schematic drawing of a retrofitted/modified
surface covering for use of solar heat energy formed in accordance
with the present invention. The surface covering has a top layer 2
and a lower layer 4 and in order to form the surface covering, the
top layer and middle layer are ground away such that a network of
conduits 50 can be installed in the recess formed by grinding. The
network of conduits 50 carry fluid to be heated and the network is
installed in, on, under or in contact with all or a portion of the
surface covering, preferably in the layer 4 (or 14 as shown in
FIGS. 5 and 6) which are high thermal conductivity layers.
[0040] The method of modifying an existing surface covering to
embed conduits therein to collect solar heat is shown in FIG. 2
where an existing surface covering 7 is removed with a grinder 6
which can be part of a piece of equipment, such as equipment moved
by a vehicle 5. The equipment can be driven by an operator or could
be a hand-driven piece of equipment. The grinder 6 removes a
portion of the existing surface covering 7 or the entire surface
covering can be removed thereby forming a recess shown by the
curved lines in FIG. 2 and the cut away portion in FIG. 1. Once the
surface covering has been ground away, the network 50 of fluid
carrying conduits can be installed in the recess and part of a
resurfacing operation for the surface covering.
[0041] As shown in FIG. 3, a method for modifying a surface
covering includes the step of softening the existing surface
covering, for example by use of a heater 8, forming a channel in
the softened surface covering, for example by use of a wheel 9,
pressing a conduit 11 into the channel, for example with use of a
wheel 13 having shaped peripheries as shown in FIG. 4 which
illustrate U-shaped and V-shaped wheel peripheries and filling the
channel with thermal conductive material to cover the conduit, for
example by means of a rotating spreader 15. The filler can be
obtained from the surface covering or can be another thermal
conductive layer of material.
[0042] As shown in FIG. 5, the resulting structure includes fluid
carrying conduits 11 embedded in the surface covering. The fluid
carrying conduits can be embedded at different lengths within the
covering with varying spacing, and the fluid carrying conduits can
be formed as a single loop, for example running down the side of a
driveway road or sidewalk or multiple loops covering the entire
area of a surface. The fluid carrying conduits are referenced as
"heat exchanger pipes" in the drawings and are shown disposed in a
high thermal conductivity layer 14. An example of a high thermal
conductivity layer is an asphalt binder with high thermal
conductivity aggregate therein increasing the efficiency of the
surface covering in capturing heat from incident solar radiation on
the covering. The high thermal conductive layer can be at any depth
within the covering so as to be in the top low thermal conductive
layer 16 and the bottom low thermal conductive layer 18. The high
thermal conductive aggregate can be created by additives such as
metal particles, wire, rods, rebar, conductive films or tapes as
well as conductive aggregate (rock) materials such as in the class
of quartzite and sandstone.
[0043] As shown in FIG. 6, the surface covering can have a top
visible transmitting and infrared/heat blocking layer on a low
thermal conductive layer and the fluid carrying conduits 11 can be
disposed between layers of asphalt 16 and 18 constituting low
thermal conductive layers. The surface covering can be created with
a visible wavelength light transmitting and infrared heat blocking
top layer with embedded fluid carrying conduits but with no
conductive layer and no lower heat insulating layer. Alternatively,
the surface covering can be made with no visible wavelength light
transmitting, infrared heat blocking top layer but with a thermal
conductive layer and lower heat insulating layer. The purpose of
the arrangement of the layers is to increase the efficiency of the
system by allowing an increased percentage of heat energy to be
captured by fluid in the conduits from the incident solar radiation
on the surface covering. The top layer creates the "greenhouse
effect" within the surface covering to allow light from the sun to
enter the surface covering while trapping heat therein whereby more
heat can be transferred to the fluid in the conduits 11 to drive a
more efficient system. The top layer can be of a material type such
as glass, ceramic, rock type materials, film, tape, a spray-on
layer and liquid that hardens, for example.
[0044] FIG. 7 shows conduits 28 (11 in FIGS. 3-6) laid in channels
30 in a surface covering. Once the conduits are installed, the
conduits can be left as is covered with another layer or the
channels can be filled with a solid, liquid or malleable material
that subsequently hardens. The fill material can be a high thermal
conductivity material.
[0045] FIG. 8 shows conduits 28 in channels 30 in a surface
covering where the surface covering has a top layer of covering
with an optional middle layer 14 of higher thermal conductivity
materials.
[0046] FIG. 9 shows positioning of the channels on the underside of
a surface of the channels 30 on the underside of a surface covering
with conduits in the channels. This arrangement is particularly
useful for roofing materials, such as shingles.
[0047] FIG. 10 shows conduits 28 in channels 30 on the underside of
a surface covering in the form of a mat 32 that can absorb solar
radiation but could also absorb heat from a surface supporting the
mat. Sloped edges of the mat allow it to be used in an area where
pedestrians or vehicles might pass such as on a roadway or parking
lot. The ability to perform a mat can provide cost savings over
more permanent installed systems.
[0048] FIG. 11 shows conduits 28 embedded in surface covering 32
where the mat could be formed by extrusion with channels and
separate conduits. The ability of mats and conduits to interlock in
a leak-free seal increases flexibility in system design. The bottom
surface of the mat can be either a thermal conductor to take heat
from the surface supporting the mat or a thermal insulator to
prevent heat from escaping to the surface below.
[0049] FIG. 12 shows a roadside guardrail 36 having a base 34
extending into the surface covering or roadway for better thermal
contact with the surface covering. Fluid carrying conduits can also
be embedded or formed in the guardrail to increase heat transfer.
The guardrail is normally formed of a metal-based thermal conductor
and can be used to capture and transport solar generated heat
either with the fluid carrying conduits or without the conduits.
The concept of utilizing roadside heat collectors can be extended
to other common roadway structures such as dividers, Jersey walls
and the like.
[0050] FIG. 12b shows the guardrail 36 being surrounded with a
thermal insulated outer layer to retain heat. Other roadway metal
structures can be similarly insulated to assist in the capture and
transport of solar thermal energy for example, bridges, overpasses,
pipes and railroad tracks.
[0051] FIGS. 13, 14 and 15 show systems for operating energy
conversion equipment, utilizing the heat and energy produced by
surface coverings modified or retrofitted in accordance with the
present invention. In FIG. 13, heat from conduits in a surface
coating is supplemented by a concentrated solar power system (CSP)
and can also be used to store the CSP heated fluids at night to
maintain higher temperatures. The system is shown operating a steam
cycle turbine 26. In FIG. 14, fluid carried by conduits in a
surface covering 20 obtained from solar radiation incident on the
covering is supplied via a heat exchanger 24 to an auxiliary heater
32 to raise the temperature before supplied to an energy conversion
device (ECD) to convert the heat into a useful form of energy. The
use of heat exchangers permits multiple circulating fluid loops to
control temperatures, pressures and flow rates, and separate fluid
storage tanks can be maintained. An optional cold source 44 can
create a higher temperature differential for the ECD. FIG. 15 shows
use of heat from solar radiation on a surface covering 20 with a
heat exchanger 24 and auxiliary heater 32 as shown in FIG. 14 for
operating energy conversion devices including hot water supply,
chiller, heat pump, ORC (organic Rankine cycle), water purification
and/or distillation units. Additionally, conduits 30 can
communicate with the surface covering 20 to supply a fluid with
increased heat through the surface covering for melting of
precipitation such as snow or ice. For this use, separate conduits
30 can be used or the conduits from the main system can be run with
the flow reversed. Multiple auxiliary heaters, such as solar
concentrators 28, can also be used in the system.
[0052] As described above, high heat conductive aggregate in an
asphalt binder improves the heat transfer in a pavement or
structure and, thus, using more conductive rocks, aggregate, can
improve heat transfer in the system. Use of thermally conductive
additives to a pavement or hot asphalt mix (HMA) could have a
negative impact on binding and structure. In addition, the high
cost of certain metal-type additives could make them prohibitive as
a conductive additive. Accordingly, the use of aggregate itself as
the conductive material instead of another thermally conductive
material that would not normally be part of the HMA or pavement is
desirable.
[0053] As explained above, the surface covering has a high thermal
conductive layer disposed within the surface between low thermal
conductive layers and can reduce the cost of what may be a more
expensive aggregate material. This layer will also make it possible
to increase efficiency as the asphalt will conduct more heat
through the layer and less energy will tend to be conducted inwards
where it cannot be used.
[0054] The heat source from the surface covering can be used in
conjunction with a system to produce cooling or air conditioning.
Specifically the low temperature heat source can be attached to an
adsorptive chiller, absorptive chiller, heat pump or other systems
that use a refrigerant, desiccant, or the like via a heat
exchanger. A chilling system that uses expanding gases to create a
cooling effect can be fueled by heat. These systems, including
adsorptive and absorptive chillers, are designed specifically to
make use of low temperature heat sources and are often used for
large scale cooling requirements. The heat that can be generated
from paved surfaces, buildings and rooftops, with average
temperatures of 120-150 F are perfectly matched for these chiller
systems. The heat is used to heat a fluid such as water or
refrigerant that is used in such systems.
[0055] Flexible pipes (conduits) can be used for collection of heat
from construction fixtures and buildings. Use of modern flexible
piping materials allows lower cost of installation and more durable
systems. The pipe/conduit itself is used for heat transfer. The
pipes are extruded in geometries favorable to heat transfer with
the outside media. Pipes extruded in different geometries such as
with fins, oval, stars and the like promote better surface area and
contact with the media. Having a pipe cross section with more
surface area towards the horizontal plane will promote heat
transfer since the top and bottom of the pavement are cooler than
the center. That is, where an oval pipe cross section is used, the
longer leg is preferably disposed vertically.
[0056] An alternate method to embedding the pipe prior to paving is
to install the pipes in pavement prior to hardening of the
pavement. Then the pipes are left exposed or are covered with an
additional material. That is, the pipe gets pressed into the
asphalt when it is still not hardened. This can be on a top layer
or a middle layer. An asphalt roadway machine can be designed to
press the hose into the still soft asphalt.
[0057] A grinding/milling machine can be used to mill a pipe
channel into a surface to create channels or grooves wherein the
pipe can be laid. The pipe is pressed into the channel, left
exposed or covered with an additional roadway layer, as required.
This arrangement is particularly effective in low energy demand
projects, like home heating and cooling and/or pool heating.
[0058] Solar thermal energy can be harvested without embedding
pipes below the surface. Materials are produced with internal pipes
or channels to create a similar result. One design resembles a
rubber speed bump with embedded grooves for the tubes, or a closed
bladder, holding fluid above the surface, facilitating the easy
placement and removal of the heating technology. Similar designs
with internal fluid carrying channels can be used in roofing
materials (shingles), siding materials, and surfacing materials
such as driveway or patio bricks or in surface composites (e.g.
Trex, or Timberteck). Thermally conductive materials, low
emissivity coatings and interlocking channels are design features
dependent upon use conditions. In the simpler version, the fluid
carrying channels are not within the materials, but grooves or
channels are manufactured into the front or underside of the
surface. Then a flexible hose or pipe is pressed into the channel.
An advantage of this design is to limit the number of connections
between panels, thus lowering the chance of a leak.
[0059] The system can collect heat from structures and buildings.
The heat conductive materials used in municipal and traffic
structures as well as buildings provide a source to capture, store
and transport heat energy. Existing heat-conductive structures in
bridges, overpasses, guardrails, railroad tracks, and the like, can
be used to collect and transport heat. The structures themselves
gain heat from incident radiation and they also act as a heat
exchanger to pull heat from the paved surfaces and structures they
are in contact with. Because of the thermal conductivity of these
metal based structures, heat can be transported. A fluid based heat
exchanger can be placed along the back of a guardrail or at
periodic intervals. These structures include, but are not limited
to, metal guardrails, metal utility poles, road signs, bridges,
overpasses, and railroad tracks. A design to promote heat exchange
between the surfaces and the metal structures and to enhance
thermal transfer can include elongated footings added to guardrails
to extend further into the roadway material. They provide
additional contact area with the adjacent paved surface which will
promote heat transfer. In another design, the structures are
thermally insulated to hold the heat within and allow it to
transport within the body to the heat exchanger. In the design
using a metal guardrail, elongated fins or feet can extract heat
from the paved surface while the plastic or rubber coated guardrail
transports the heat within its metal structure to a heat
exchanger.
[0060] The fluid carrying conduit of the system can be designed in
a closed loop, where a heat exchanger is used to extract the heat.
The heat exchanger is used to transfer heat from the fluid to a
second fluid for use in various systems, i.e., to have two
independent fluid loops so that the fluid that is used to collect
the heat is kept separate from the working fluid used in the target
system. Alternatively, the heat exchanger could be a radiator or
similar structure to heat buildings (e.g., homes, hotels/motels,
office buildings, etc.)
[0061] A heat exchanger between systems has several advantages
including, but not limited to, fluids made up of different
materials and are managed for different contaminants to add a
longer life to the systems and allow for easier maintenance.
[0062] The heating source described herein can be used to produce,
or assist in producing, clean or fresh water (desalination) and to
reclaim and recycle wastewater. Certain purification processes are
achieved from low temperature heating of the water. Low grade
waters are used for irrigation systems for crops and the like.
Pasteurization temperatures of 70.degree. C. are achieved by the
system. Clean water is becoming a scarce resource in some regions
of the country and world. These systems will be used by governments
or private property owners. In the Pacific southwest of the US,
there are already shortages and rationing. Fighting for the limited
sources between agriculture, towns and cities is underway.
Meanwhile, this is still one of the fastest growing areas for
population and construction of commercial and residential
properties. Farms, lawns, golf courses and the like all have
requirements for water. There are differences in water quality:
potable, drinkable, for lawns, ponds, other uses. Further,
desalination as a technology is important in areas of the world
where fresh water is in short supply. The present heat source can
be used for water purification and desalinization in membrane based
purification systems. The higher temperature water contains
atoms/molecules in an excited state which allows for easier
separation of the undesirable elements at the membrane filter.
Easier separation results in lower energy costs to push the fluid
through the membrane. A further benefit is to keep the filters
cleaner, preventing clogging, which allow a longer membrane filter
life, lower energy costs and lower (less frequent) replacement
costs.
[0063] Inasmuch as the present invention is subject to many
variations, modifications and changes in detail, it is intended
that all subject matter discussed above or shown in the
accompanying drawings be interpreted as illustrative only and not
be taken in a limiting sense.
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