This invention relates to the field of renewable energy. Specifically, this invention relates to the large-scale creation and storage of ice using ambient environmental conditions.
Currently, most of the world's economies are reliant on fossil fuels. Fossil fuels have many drawbacks. Fossil fuels pollute. This pollution is largely responsible for the greenhouse effect. Additionally, the pollution from fossil fuels makes the air in many major cities, such as Mexico City, Beijing, and Los Angeles, unhealthy to breathe for many people. The procurement of fossil fuels, whether in mining coal or drilling for petroleum, is inherently polluting. Mountain top removal for coal and fracking for natural gas both contaminate ground water, endangering the life and health of those living nearby. Drilling for petroleum is also fraught with hazard. Witness the BP drilling catastrophe in the Gulf of Mexico in 2010 or the grounding of the Exxon Valdez in 1989.
Fossil fuels give undue influence to the governments who control exportable quantities of the resource. The majority of exported crude petroleum comes from areas of the worlds that have potentially unstable governments, or governments that are in tension with the West. For instance, much of the exported oil that America receives comes from the Middle East. Many of the regimes that export oil are openly hostile to the United States, notably Iran. Many of the other regimes are run by autocratic governments, such as Saudi Arabia and Kuwait, which can be seen as potentially unstable, in light of the Arab Spring. The U.S. secures additional petroleum from Venezuela, which, in recent history, has had a strained relationship with the U.S. Western Europe procures much of its fossil fuels from Russia, an historic competitor with the West. To the extent that fossil fuels are imported, needlessly, a nation is exporting its wealth, needlessly.
Fossil fuels are also becoming increasingly scarce, meaning that their price is rising. The International Energy Agency states that 2006 was the peak year of petroleum production. The global output of petroleum will now slowly decline. Meanwhile, the BRIG countries (Brazil, Russia, India, and China) are rapidly growing, driving demand for petroleum upwards. This has led to volatility in the oil markets, with the cost of a barrel of oil peaking at $140 in 2008. Since then, the price for crude oil has varied from a low of $70 per barrel to a high of $110 per barrel. All indicators are that the price of a wide variety of fossil fuels will steadily increase, faster than other goods, until they are exhausted.
In response to the drawbacks of fossil fuels, industry, governments, and academic institutions have been pouring resources into finding renewable energy sources for years. To date, the results have been mixed. Current renewable resources have three drawbacks: cost, environmental impact, and consistency of availability. The cost of a renewable energy source is measured by various metrics: Return on Investment (“ROI”), cost per kilowatt hour (“CPKH”), levelized cost of energy (“LCE”), etc. In order to be competitive, the CPKH must be comparable to that of fossil fuel. Alternately, the ROI must have a realistic payback, in terms of the number of years required for a given installation to save money. Currently, no renewable sources are cheaper than fossil fuels.
Many renewable energy sources have a significant environmental impact. Environmental impact means not only pollution, but also a visible, intrusive installation foot-print. For example, in order to generate usable quantities of solar energy using photo-voltaic cells (“PV”), one needs to have a sunny location and a very large surface area. In order to produce wind energy economically, most developers use wind farms, requiring acres of wind-turbines. In order to produce hydro-electric energy, a dam must be built, disturbing wetlands and delicate eco-systems. In order to produce ethynol, farmers must grow corn on industrial scales, using significant amounts of lands, water, petroleum, and pesticides (to date, no ethynol growers are doing so organically).
Last, many renewable energy installations are limited as to the times that they can provide power. For example, PV only provides power when it is sunny. Peak electricity demand is typically in the hours around and after dusk, right when the PV loses its generating capacity. Wind turbines only provide power when it's windy. This means that a wind turbine can only add to the grid when there is wind. When the wind dies down, the grid must be able to provide power using other means. The inconsistency of power generation reduces the appeal of these renewable energy resources.
Clearly, the world is searching for a renewable energy resource which is cost-effective, has a low environmental impact, and is consistent in its generating capacity. Ideally, such a system would be able to capture energy, and store it, for later use. One potentially under-appreciated component of such a system is water.
Water has both a high thermal capacity and a high latent heat needed to be fuse. A high thermal capacity means that water can absorb significant heat without extreme changes in its temperature. Likewise, water can radiate significant heat without extreme changes in its temperature. Water is also unique in that its heat capacity does not drastically change when it changes phase. For example the specific heat of ice is still half that of liquid water. The latent heat necessary to fuse water into ice is, also, substantial. A metric ton of ice measures is approximately one cubic meter, and contains in excess of 90 kW-hr of energy due to latent heat of fusion. Additionally, a cubic meter of water (a metric ton of water) will release approximately 20 kW-hr of energy, when rising 0° C. to 18° C. As a rough rule of thumb, every cubic meter of ice (every metric ton of ice) contains 110 kW-hr of energy between its fused state (as ice) and its liquid state at 18° C.
To put that in perspective, according to a study by U.C. Irvine, the average, annual household consumption of energy in southern California in 2007 was 6 MW-hr. To store 6 MW-hr of energy in the latent heat of ice would require a block of ice approximately 64 m3, or about 4 meters on a side. According to the Energy Information Agency, in 2001, the average household that had central air-conditioning used 2.8 MW-hr to power the air conditioner. To store 2.8 MW-hr of energy in the latent heat of ice would require a block of ice approximately 30 m3, or about 3.1 meters on a side.
In most of the temperate part of the world, it is relatively easy to sequester water from the environment, either through precipitation or ground-water. Additionally, the relatively low-cost of water from municipal sources makes large-scale water impoundment economically feasible.
The combined latent heat and thermal capacity means that ice can store a substantial amount of energy. Said another way, ice can provide a substantial amount of cooling to the ambient environment.
The trick is to make the ice large enough that the environmental losses when the temperature is high (i.e., summer) is relatively low compared to the overall amount of stored energy. The combined latent heat of fusion and thermal capacity is proportional to volume. The environmental losses (radiation losses) are proportional to surface area. As a result, the larger the block of ice, the more efficient it is as an energy storage solution.
No large scale energy storage systems exist, which use ice or cold-water on such a large scale. Before modern refrigerators, work-men used to cut blocks of ice from lakes, and store them in caves or icehouses until the summer. In the summer, the blocks of ice would be sold. Due to the weight of the ice, the largest blocks had to remain small enough to efficiently move them. Although the ability of ice to hold cold energy has been known for at least a century, the prior art does not anticipate the use of ice to cool on an industrial scale.
Currently, multiple manufacturers offer ice forming systems to level-load their air-conditioner system, reducing load at peak demand times. The blocks of ice used are modest in size, being about the size of a small refrigerator. The reason for the size limitation is that roof-mounted air-conditioners cannot add the weight needed to use ice as a large scale cooling source. Ice Energy Inc. makes such a unit, which uses 450 gallons of water, or approximately 1.75 cubic meters of ice. This volume would be capable of storing about 160-170 kW-hr of energy.
The present invention is to store ambient environmental energy in cold water or ice, on a large enough scale, that it becomes practical as part of a renewable energy system for residential, office, and industrial uses. It is a technology that is practical both in areas where there are freezing temperatures in the winter and in places that never freeze. In climates where the winter brings freezing conditions, it is possible to freeze large amounts of water. In much of the world, the night is significantly colder than the day, allowing for ice formation, or cold water retention.
The present system is comprised of a system or method for making and storing large scales of ice or cold water, a cover or other method of insulating the ice and water store, a piping system connecting the storage area to a heat exchanger, a liquid-to-air heat exchanger, a controller that regulates the flow of cold liquid to the heat exchanger, and a device that allows the cold energy to be removed from the storage area. The liquid medium can be the melt water from the storage area or a closed glycol system. In systems in which the liquid medium is melt water, the device that allows for the removal of cold energy from the storage area is a drain. In systems in which the liquid medium is glycol, the device that allows for the removal of cold energy from the storage area is a liquid-to-liquid heat exchanger.
The system or method for making and storing large scales of ice can vary, depending on the application, the terrain, local zoning ordinances, access to natural or man-made bodies of water, the cost of installation, and other building factors that are evident to those skilled in the trade. The systems and methods for making and storing large scales of ice listed in this patent application are meant to be illustrative in nature, and do not limit the breadth or scope of the claims.
The following description represents the inventors' current preferred embodiment. The description is not meant to limit the invention, but rather to illustrate its general principles of operation. Examples are illustrated with the accompanying drawings. A variety of drawings are offered, showing the present invention, using different methods for forming ice and storing ice.
The invention is a renewable energy system for use in residential, commercial and industrial buildings. The system uses, as one of its components, a large-scale energy storage system. The large-scale energy storage system ice or cold water, and is designed with due consideration of the climate, terrain, zoning, property size, and installation cost. The cold mass is connected to a liquid-to-air heat exchanger. The heat exchanger uses the cold from the cold mass to cool the ambient temperature in the building.
At the bottom of the cold mass 40 is a drain 4 to regulate the removal of energy from the mass, through the removal of melt-water. The drain 4 will have a controller/valve 5, which controls when melt-water is removed. The drain 4 is connected with piping 6. The piping 6 sends melt-water to a pump 7. The arrows on the piping 6 indicate the direction of cold energy flow and material flow. The pump 7 pumps material to the feed pipe 35, which connects to a liquid-to-air heat exchanger 10. Cold air is then sent into the building 38.
The destination of the return melt-water can be routed in three different directions. The melt-water can flow through a return pipe 8, which can route melt-water to either the bottom of the cold storage mass or to the top of the cold storage mass. The routing of water through the return pipe 8, and the pressurization of the return pipe 8, is accomplished with a plurality of multi-ported pumps 14. Each multi-ported pump 14 contains a controller, which will correctly route the water depending on environmental conditions and the amount of mass in the cold storage basin. In the summertime, a multi-ported pump 14 can route water to the roof, through a feed pipe 15. The system contains a pressure valve and cleaning port 9.
In order to compact the mass 40, the system may, optionally, includes a dosing rod 36. When forced into the mound of snow, the dosing rod 36 splays at the bottom. Each end of the dosing rod 36 contains a water hose. The dosing rod 36 can be used to reduce a snow mass to liquid, so that more mass can fit in the basin. The dosing rod 36 can be connected to the melt-water return pipe 8 in a melt-water system.
Without additional measures, the maximum height of ice storage 20 is lower than that when using snow
In climatic areas where ice routinely forms in the winter, the system can be augmented to both collect melt-water from the roof, and cool the roof in the summer. In such a system, the pipe 15 extends to a roof-mounted sprinkler (not shown) so that it reaches the roof. The pump 14 can then pump water onto the roof. At the bottom of the gutter, the system would contain a control box 16 that would send melt-water into the retention basis via a pipe 17, if the melt-water was cold and there was room in the retention basin. Otherwise, the water would be sent through a shunt pipe 18 to irrigate the land.
The Ice Ditch is the preferred embodiment for cost of installation and efficiency, in cold climates. In an installation without a natural swale, and in which a man-made swale is not practical, either because of zoning, terrain, or cost, the storage capacity of an Ice Ditch may make that method of forming cold water and ice less than ideal. If a swale is not possible, it may be possible, on some installations, to build a small structure to facilitate cold energy storage.
As in previous systems, there will be piping 6, pumps 7, 14, a liquid-to-air heat exchanger 10, forced cold air into the building structure 38, feed pipe 35 to the heat exchanger, a return pipe 8, a relief and cleaning port 9, a melt-water pipe 15 designed to pump water onto the roof, a control box 16, a melt-water routing pipe 17 back to the cold mass, and a shunt pipe 18. The return pipe 8 feeds another set of pipes 31 that return the melt-water to the structure.
The structure may, also, have a refrigeration pipe 26, filled with glycol and sealed at both ends. This pipe 26 will be affected by both the temperature gradients of the substances touching it (ice, melt-water, air inside the structure 21, and external air). When the air outside is colder than the material inside the structure 21, the pipe 26 will facilitate ice formation.
The structure can also have cooling panels 42, 44, which capture ambient cold energy from the roof, and feed it to a cooling panel 43 in the structure 21. The interior cooling panel 43 is made of a plurality of pipes, bounded or molded together, through which the transport medium can flow. The panels 42, 43, 44, use glycol as an energy transport medium through hoses or pipes 41. Ice build-up on the cooling panel 43 within the structure 21 can be reduced or prevented by, among other things, torqueing and/or twisting the panel 43 headers intermittently; running warmed glycol through the panel 43; increasing and decreasing the fluid pressure within the panels 43; and using acoustic exciters to knock ice off the panels 43.
In some installations, it may be desirable to make and store ice in locations not adjacent to the ground (e.g., commercial or industrial roof-tops). In any installation where it is desired to make ice using energy provided by the environment, ice formation is possible with a method called the Ice Cube.
The Iceberg, Ice Ditch, or Ice Cube can all three use a drain to remove melt-water.
The concept of using the melt-water for evaporative cooling also applies to parking lots.
Number | Date | Country | |
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61633037 | Feb 2012 | US |