Abstract:
A system for operating environmental equipment with improved efficiency including a surface covering having fluid carrying conduits and surface structure heated by solar radiation to heat the fluid with the fluid carrying conduits having non-round cross-sectional shapes to provide increased heat transfer contact surfaces, a heat exchanger communicating with the conduits and energy conversion equipment coupled with the heat exchanger to utilize the heat generated energy for operation.

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 with improved efficiency including manufactured (paved) surfaces and, more particularly, to using the power/energy in the form of heat obtained from solar radiation 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&#39;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 2 ). This same study further describes that 1.05% of the United States of America land area is constructed, impervious surface (83,337 km 2 ) and 0.43% of the world&#39;s land surface (579,703 km 2 ) is constructed, impervious surface. China has more impervious surface area than any other country (87,182 km 2 ) but has only 67 m 2  of impervious surface area per person, compared to 297 m 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&#39;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° F. (27-50° 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&#39;s environment and quality of life; the majority negative. These impacts include: 
         [0000]    (1) Increased energy demand for cooling. Research shows that electricity demand for cooling increases 1.5-2.0% for every 1° F. (0.6° C.) increase in air temperature, starting from 68 to 77° F. (20 to 25° 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° F. (38° C.) can elevate initial rainwater temperature from roughly 70° F. (21° C.) to over 95° F. (35° 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). 
         [0014]    Heat island mitigation is part of a community&#39;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. 
         [0015]    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. 
         [0016]    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. 
         [0017]    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&#39;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 
       [0018]    The methods and systems of the present invention use the heat absorbed by surfaces from incident solar radiation to produce energy in various forms. The systems and methods can use embedded thermally conductive materials or fluid carrying pipes 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 and methods can also produce electrical power through a low temperature generator such as one powered by an organic Rankine cycle engine. Heat from the system can drive an absorptive or adsorptive chiller to produce an air conditioning or cooling system. The system 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 per 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. 
         [0019]    The present invention 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 surfaces 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 systems. This provides a means of converting raw heat into more tangible or useful applications. A network of pipes 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 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. The system can be used in conjunction with other energy sources, namely geothermal, photovoltaic, and biofuel. Additional uses include the use of these methods as a means to purify, decontaminate, desalinate, and clean water and to take heat from buildings and roadway structures. 
         [0020]    Classic pyramidal geological charts as illustrated in  FIGS. 18 and 19  show thermal conductivity of basic rock-forming minerals and compositional relationship with rocks.  FIG. 18  shows metamorphic rocks, and  FIG. 19  shows volcanic and sedimentary rocks. Metamorphic and volcanic rocks are in italics, plutonic and sedimentary rocks are not italicized. For volcanic and sedimentary rocks the third “mineral” phase is air or water, due to the great importance of porosity for the thermal conductivity of these rocks. Using the more conductive rocks such as quartzite can improve heat transfer in the system. Typically, it is most cost effective to construct new roadways, buildings, cements and asphalts with locally available materials. Transport of large volumes of construction materials can become expensive and unnecessary if the needed materials are available locally while using a (thin) conductive layer reduces the costs 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. By making slight adjustments to pavement composition, and adding a network of pipes below the surface, the latent heat stored from the sun can be extracted more efficiently for practical use. Asphalt is a near perfect black body and specific aggregate materials increase the efficiency in collecting low energy solar heat incident to pavement to produce useful work and more particularly to: [a] the collection of low energy solar heat sources through an embedded heat exchanger system in a paved surface; [b] the use of water or water-based fluid, a low temperature liquid-vapor phase change heat exchanger working fluid or commercially available specialty electronic cooling fluids; [c] the application of the particular aforementioned collected heat energy system for use with an absorption chiller, low-heat energy heat pump or organic Rankine cycle mechanism; and [d] the use of the combined embedded paved surface heat exchanger with the chiller to cool a building environment, with a heat pump to warm the building environment and with an organic Rankine cycle mechanism system to generate electricity or to produce a hot water source for multiple applications including water purification and distillation. 
         [0021]    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. 
         [0022]    When using the present invention 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. 
         [0023]    One aspect of the present invention is to improve the efficiency and/or lower the cost of heat gathering in a solar heated surface. One improvement is use of a double loop heat exchanger, heat exchangers between the loops to allow for heat transfer from a first body of fluid which is taking heat from the covering, to a second or third body where use will be made of that heat. Fluid storage tanks or multiple fluid storage tanks can be used. Computerized control systems can be used to control temperatures, flow rates and pressures of the fluids within the tanks and conduits. Flexible tubing with improved efficiencies include changing the geometries of the tubes and making them, or the surrounding material, more thermally conductive. A thermal conductive layer within the covering at the level of the conduits improves system efficiencies. A top layer that transmits visible light but blocks infrared heat traps heat within the covering. Likewise, a bottom insulating layer prevents heat from escaping into the surface below. The roadway structures that improve efficiencies include guardrails, bridges, and railroad tracks. Changing the thermal conductivity and methods of applying certain aggregate materials improve heat transfer from surfaces. In addition, forming of tubing within a “mat” structure adds to efficient heat transfer from a surface. 
         [0024]    The present invention substantially improves harvesting of solar energy/heat by increasing efficiencies and lowering costs of a solar roadway system. 
         [0025]    A further aspect of the present invention is to simultaneously take advantage of the available and sustainable solar heat source to add a fifth strategy to heat island mitigation by utilizing a pavement embedded heat exchanger to deliver urban island waste heat that is particularly applicable to the working characteristic of an absorption chiller or an organic Rankine cycle engine. The methods and systems of the present invention simultaneously reduce energy demand for cooling while supplying a source of electrical energy to the grid, reduce the amount of air pollutants generated by fossil fuel fired electrical generating plants, enhance human comfort, and alleviate storm-water run-off temperatures. 
         [0026]    In another aspect, the present invention uses heat from solar radiation on manufactured surfaces as an energy source. In one of its simplest forms the energy can be used to provide hot water to a system or structure. In other forms the energy can be used to provide cooling with an absorption or adsorption chiller, to provide electrical power with an organic Rankine cycle engine or to provide heating or cooling with a heat pump system. 
         [0027]    The present invention overcomes or substantially alleviates long term problems of the prior art relating to thermal heat islands while providing cost effective delivery of solar energy conversion into electrical energy, heating or cooling. 
         [0028]    Another aspect of the present invention is to use energy from solar radiation collected from manufactured surfaces as auxiliary and/or supplemental heat sources integrated to provide higher temperatures and to provide a broader energy source useful for operation of energy conversion equipment such as hot water supply, chillers (absorptive and adsorptive), heat pumps, organic Rankine cycles and integration into systems for water purification and distillation. 
         [0029]    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 
         [0030]      FIG. 1  is a schematic drawing showing an embodiment of conduits embedded in a surface covering with solar radiation incident on the covering. 
           [0031]      FIG. 2  is a schematic drawing showing a high thermal conductivity aggregate in an asphalt binder. 
           [0032]      FIG. 3  is a schematic drawing showing a heat exchanger pipe or conduit embedded in a surface covering. 
           [0033]      FIG. 4  is a schematic drawing showing a heat exchanger pipe embedded in a layered surface covering. 
           [0034]      FIG. 5  is a schematic drawing showing conduits with different transverse shapes to promote thermal contact with the surface covering. 
           [0035]      FIG. 6  is a schematic drawing showing an embodiment of an elongated shaped conduit/pipe in a surface covering with a high conductive layer. 
           [0036]      FIG. 7  is a schematic drawing showing conduits laid in channels on a surface covering 
           [0037]      FIG. 8  is a schematic drawing showing conduits in channels on a surface covering with a top layer of covering and an optional middle layer of higher thermal conductivity materials. 
           [0038]      FIG. 9  is a schematic drawing showing channels or grooves on the underside of a surface covering with conduits in the channels 
           [0039]      FIG. 10  is a schematic drawing showing conduits in channels on the underside of a surface covering. 
           [0040]      FIG. 11  is a schematic drawing showing conduits embedded in a surface covering. 
           [0041]      FIG. 12A  is a schematic drawing showing a guardrail with a base that goes into the surface covering or roadway. 
           [0042]      FIG. 12B  is a schematic drawing showing a guardrail with a thermal insulated outer coating. 
           [0043]      FIG. 13  is a schematic drawing showing a surface covering for use in conjunction with a Concentrated Solar Power system 
           [0044]      FIG. 14  is a schematic drawing showing the system as a water purification unit. 
           [0045]      FIG. 15  is a schematic drawing showing conduits embedded in a surface covering with solar radiation incident on the covering with an auxiliary heater to raise the temperature of the fluid coming from the covering and an Energy Conversion Device to convert the heated fluid into a useful form of energy. 
           [0046]      FIG. 16  is a schematic drawing showing conduits embedded in a surface covering with solar radiation incident on the covering with an auxiliary heater to raise the temperature of the fluid coming from the covering and an Energy Conversion Device to convert the heated fluid into a useful form of energy. Multiple auxiliary heaters can be used in this case depicted by a rooftop solar concentrator. 
           [0047]      FIG. 17  is a schematic drawing showing the system with multiple forms of the Energy Conversion Device and conduits for the transfer of hot fluid from the auxiliary heater to the surface covering. 
           [0048]      FIGS. 18 and 19  illustrate thermal conductivity of basic rock-forming minerals and compositional relationship with metamorphic and platonic rocks and volcanic and sedimentary rocks, respectively. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0049]      FIG. 1  is a schematic drawing showing conduits embedded in a surface covering  20  with solar radiation incident on the covering. The fluid carrying conduits are installed in, on, under, next to, in contact with all or a portion of the covering. The fluid is heated by the covering which in turn is heated by the incident solar radiation. 
         [0050]      FIG. 2  is a schematic drawing showing a high thermal conductivity aggregate  10  in an asphalt binder  12 . Generally surface coverings such as pavements made of concrete and asphalt mix do not have a high thermal conductivity and might be considered thermal insulators rather than thermal conductors. The surface covering shown uses a high thermal conductive aggregate such as in the family of quartzite or sandstone to be part of the asphalt mix. 
         [0051]      FIG. 3  is a schematic drawing showing the heat exchanger pipe or conduit embedded in a surface covering with a layer of the covering  14  at the level of the heat exchanger pipe of higher thermal conductivity than the surrounding layers to allow for better heat transfer and thus a higher capture rate of the incident solar radiation on the surface covering being converted to heat in the fluid within the conduit. For a snow melt application, the high thermal conductivity layer can help to transfer the heat from an auxiliary heater to the surface covering. 
         [0052]      FIG. 4  is a schematic drawing showing a heat exchanger pipe embedded in a layered surface covering to improve the solar capture rate and improve the efficiency of the heat transfer to the system. One, all, or combinations of the following are used to improve the heat capture and transfer efficiency of the surface covering: a visible transmitting/infrared heat blocking top layer, thermal conductive layer  14 , and a bottom thermal insulating layer. The surface covering can be made of an asphalt aggregate  16 ,  18 . The thermally conductive layer can be formed by putting thermally conductive additives in the mix. The additives are typically in the form of aggregates that are more conductive than others such as in the class of quartzite or sandstone, layers of metal rods, mesh or rebar are other examples to create a conductive layer. The conductive layer may be at the level of the conduits  14  to increase heat transfer to the conduit and then to the fluid inside. For the snow melt application, the high thermal conductivity layer can help to transfer the heat from the auxiliary heater to the surface covering. Conduits can be laid in all or a section of the available surface. 
         [0053]      FIG. 5  is a schematic drawing showing cross-sectional shapes of conduits  28  with different shapes to promote thermal contact with the surface covering. Any geometry to promote thermal contact can be used such as here depicting a conduit with fins, a star-shaped conduit and an oval-shaped conduit. An outer layer or shell on the conduit that is soft, malleable to fill the contact gaps with the covering and or a high conductivity outer layer on the conduit promotes better heat transfer. 
         [0054]      FIG. 6  is a schematic drawing showing an elongated shaped conduit/pipe  28  in a surface covering with a high conductive layer  14 . With the narrow side of the conduit at the top and bottom, less energy may escape to the cooler top surface and bottom. Since more surface area is exposed on the side of the conduit, more lateral heat transfer from the surface covering to the conduit and fluid takes place. A thicker or thermal insulated top and bottom section of the conduit and thinner more thermal conductive side walls promote better heat transfer. 
         [0055]      FIG. 7  is a schematic drawing showing conduits  28  laid in channels  30  on a surface covering. Once the conduits are installed they can be left as-is, covered with another layer or the channels can be filled in with a solid, or liquid or malleable material that would subsequently harden. The fill material can be of high thermal conductivity material. 
         [0056]      FIG. 8  is a schematic drawing showing conduits  28  in channels  30  on a surface covering with a top layer of covering and an optional middle layer  14  of higher thermal conductivity materials. 
         [0057]      FIG. 9  is a schematic drawing showing channels or grooves  30  on the underside of a surface covering with conduits  28  in the channels. This arrangement is particularly useful for roofing material, such as shingles. 
         [0058]      FIG. 10  is a schematic drawing showing conduits in channels on the underside of a surface covering such as a mat that can absorb solar radiation but can also absorb heat from the surface it is laying upon. Slanted edges allow it to be used in an area where pedestrians or vehicles might pass, such as a roadway or parking lot. The ability to pre-form a mat provides cost savings over more permanent installed systems. 
         [0059]      FIG. 11  is a schematic drawing showing conduits embedded in a surface covering. Extrusion or formation of a matt with embedded channels has advantages over a matt with channels and separate conduits. The ability of mats and their conduits to interlock in leak-free seals offers flexibility to system design. The bottom surface could be either a thermal conductor to take heat from the surface it sits on or a thermal insulator to prevent heat from escaping to the surface below. 
         [0060]      FIG. 12  is a schematic drawing showing a guardrail  36  with a base  34  that goes into the surface covering or roadway and can be extended for better contact with the covering. Conduits attached to, embedded or formed in the guardrail can serve as a means of heat transfer. The guardrail itself, being of a metal-based thermal conductor, serves as a means to capture and transport solar generated heat either with or without conduits. The technology can be used in other common roadway structures, such as dividers, Jersey walls and the like. 
         [0061]      FIG. 12B  is a schematic drawing showing a guardrail  36  with a thermal insulated outer coating  38  to retain the heat. Other metal structures, such as a bridge, overpass, pipes, railroad tracks, electrical or lighting structures can be insulated to become a vehicle for capture and transport of solar thermal energy. 
         [0062]      FIG. 13  is a schematic drawing showing a surface covering for use in conjunction with a Concentrated Solar Power system. The surface covering system can be used to preheat the water for the CSP system and or to store the CSP system heated fluids at night so as to maintain higher temperatures. A steam cycle engine  26  or other form of Energy Conversion Device, can be used to produce power. 
         [0063]      FIG. 14  is a schematic drawing showing the system as a water purification unit with conduits embedded in a surface covering with solar radiation incident on the covering. The fluid is heated by the covering which has been heated by the incident solar radiation. The heat exchanger allows a second or multiple circulating loops of fluids to be used, which can be controlled at different rates to vary temperature and pressure. The water purification unit can be of several types including for pasteurization, filtration, osmosis, and distillation. The distillation unit or process can be used for applications other than for water purification such as for distillation for fractional separation of chemicals. 
         [0064]      FIG. 15  is a schematic drawing showing conduits embedded in a surface covering  20  with solar radiation incident on the covering with an auxiliary heater  32  to raise the temperature of the fluid coming from the covering and an Energy Conversion Device (ECD)  40  to convert the heated fluid into a useful form of energy. Heat exchangers allow multiple circulating fluids 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. 
         [0065]      FIG. 16  is a schematic drawing showing conduits embedded in a surface covering  20  with solar radiation incident on the covering with an auxiliary heater  32  to raise the temperature of the fluid coming from the covering and an Energy Conversion Device  34  to convert the heated fluid into a useful form of energy. An optional cold source  44  can create a higher temperature differential for the ECD. Multiple auxiliary heaters can be used, for example, a rooftop solar concentrator  28 . 
         [0066]      FIG. 17  is a schematic drawing showing the system with multiple forms of the Energy Conversion Device and conduits for the transfer of heated fluid from the auxiliary heater to the surface covering for precipitation/ice/snow melt  30 . The Energy Conversion Device can be one of or combinations of, hot water supply, chiller, ORC, Heat Pump, Water Purification or Distillation unit. A liquid-vapor phase change, including a steam cycle, are also options for the ECD which would fit into distillation or ORC type conversion technologies. There are many facilities that have demands for multiple forms of energy supply. Hotels, for example, have hot water demands to provide washing facilities to the guest rooms and for laundry which is done after each guest stay. A hotel also might have a need for air conditioning (chilling), and perhaps a need for water purification capabilities. The combinations of systems depicted offer the capability to satisfy the requirements of a facility. The hot water source can be used for many applications for preheating of boilers and manufacturing/plant process water and for hydrogen production and biofuel production. The reverse flow conduits  30  supply heated fluid from the auxiliary heater to the surface covering for the purpose of snow and ice melting. They could be separate conduits  30  or use the conduits from the main system running with a heated fluid from the auxiliary heater. In certain regions of the world, at certain times of year, the climate may not allow a heated fluid to be produced from the surface covering. Low outside temperature (e.g. in winter) or overcast skies could prevent the system from working properly. Combining the feature of a snow/ice melt system adds value to the system in temperate regions. As shown, the auxiliary heater puts a heated fluid into the surface covering to melt snow and ice. Multiple auxiliary heaters such as the solar concentrator  28  depicted on the rooftop can be used. 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. 
         [0067]    Typically, it is most cost effective to construct new roadways, buildings cements and asphalts with locally available materials. Transport of large volumes of construction materials can become expensive and unnecessary if the needed materials are available locally. However, if thermally conductive materials are not available locally, the method of the present invention may require such materials to be purchased and transported from non-local sources. It is not always in the financial best interest to transport these materials from potentially distant sources, but with the present system there is incentive to do so. 
         [0068]    As explained above, the manufactured 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. 
         [0069]    The heat source from the manufactured 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. 
         [0070]    The heat source from the manufactured surface covering can be used in conjunction with an organic Rankine cycle (ORC) system which uses an expanding low temperature gas to drive a turbine. ORC systems are currently being designed to work with geothermal heat sources. 
         [0071]    In another embodiment, 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 with the present invention. 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. 
         [0072]    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. 
         [0073]    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. 
         [0074]    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). All the advantages of design are then applied to these “pre-fabricated” materials. Thermally conductive materials, low emissivity coatings and interlocking channels are design features dependent upon use conditions. In a simpler version, the fluid carrying channels are not within the materials, but a groove or channel is 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. 
         [0075]    One manufactured surface covering has a narrow mat running up the side of a driveway or roadway. This will provide an additional safety measure to drivers as they will feel the hump if they accidentally come out of a lane and in danger of getting off of the road. 
         [0076]    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 guard rails, 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. 
         [0077]    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.) 
         [0078]    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. 
         [0079]    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° 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. 
         [0080]    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.