Insulated storage tank

An insulated storage tank incorporating modular panels includes a structural rigidity to store large volumes of hot and cold liquids. The insulated storage tank includes a plurality of insulating panels disposed on an insulation substrate in a circumferential pattern, the insulating panels each in proximate contact with two other panels forming a cylindrical wall. The insulating panels are a rigid structure and provide structural support to an inner liner disposed within the cylindrical wall and operable to be filled with a hot or cold liquid. The cylindrical wall of insulating panels is further supported by a thin outer support jacket. The insulated storage tank has a lid disposed on the insulating panels thereby sealing the contents of the insulated storage tank.

FIELD

The present disclosure relates to thermally insulated storage tanks. More particularly, the present technology relates to a modular, thermally insulated storage tank for storing hot or cold liquids.

BACKGROUND

Each day, the sun provides 10,000 times the amount of energy utilized by the human race. In a single day, it provides more energy than our current population would consume in 27 years. In North America alone, it is believed that close to two trillion dollars is spent annually on energy, much of which is designated towards non-renewable, carbon-based sources, such as oil, coal, and other fossil fuels. When energy consumption for the average U.S. household is approximately 65-80% thermal and approximately 20-35% electrical, it makes sense to derive a means of satisfying both of these requirements through renewable sources.

There have been many advances in the past few decades toward the capture of renewable energy resources, such as water turbines (which convert the kinetic energy of moving water into electricity), wind generators (which convert the energy of the wind into electrical energy), geothermal heating (which utilizes the stability of the subterraneous temperature to provide thermal energy), and solar cells (which allow the capture and conversion of solar energy into electrical energy).

An alternative type of renewable energy is a solar thermal heat exchanger, which utilizes the energy of sunlight to heat a liquid, thereby providing thermal energy for heating or cooling. In this type of energy harnessing, typically a flat plate is blackened on the front to improve absorption of solar radiation and is arranged with its blackened surface facing the sun and sloped at a suitable angle to optimize the energy collected. A series of tubes is secured to the panel, and water to be heated is circulated through these tubes to extract the heat received by the panel. The innovative thermal capture systems require that the circulated heated water be stored for further energy extraction. The warmed water from solar thermal heat exchangers is normally circulated through a separate tank so that the temperature may build up to a maximum value being a balance between the heat input and heat losses in the system. This water can then be used as feed water for heating non-heated water for domestic use through the use of in tank heat exchangers.

While the volumes of heated recirculation water varies with the size of the solar thermal heat exchangers mounted to a residential or commercial structure, a tank of sufficient size to store all of the systems liquid is required to be maintained on site. To maximize thermal energy capture, these liquid storage tanks are often located in basements of homes and businesses, particularly in the northern climates where placement of the storage tank in the exterior of the building structure may lead to tank failure and at best, loss of captured thermal energy, especially in the winter months. Similar but opposite considerations apply for the storage of cold liquids, refrigerants and the like in warmer climates, where the most suitable storage location for these tanks are also often in lower levels of the home or business, especially during the hotter months.

Often, large prefabricated storage tanks are difficult to maneuver and placement in lower levels and basements of homes and businesses are hampered by the fact that the average door widths range from 87 to 92 cm (34¼ to 36¼ inches), far smaller than the dimensions of the storage tanks. Moreover, given their bulk and weight, prefabricated storage tanks in capacities of hundreds of gallons to thousands of gallons are difficult to reposition once they have been previously established.

SUMMARY

It is therefore an object of the present technology to provide a thermally insulated storage tank, which may provide a temperature, regulated liquid for circulation to an outside tank or other thermal capture devices.

It is another object of the present technology to provide a thermally insulated storage tank that is thermally highly efficient in design, by being modular and easily assembled in difficult to reach areas.

A further object of the present technology is to provide a thermally regulated storage tank that can interface with a business or residential thermal capture panel system. A liquid stored in the thermally insulated tank is capable of heating or cooling a second source of circulating water for domestic or commercial use. When the stored liquid is hot, it can then be recirculated back to the thermal capture system to become reheated again.

Finally, it is an object of the present technology to provide an insulated storage tank, which is both economical and simple to manufacture, as well as easy to install.

These and other objects will become apparent from the present technology comprising an insulated storage tank designed to incorporate a means of storing both hot and cold liquids including water, antifreeze and compressed liquefied gasses. The insulated storage tank includes an inner liner supported by a plurality of vertical insulating panels. The insulating panels are arranged circumferentially to form a cylinder, each insulating panel in contact with a leading edge and a trailing edge of another insulating panel. The insulating panels are freestanding and are further supported by an outer support jacket. The liquid is placed within the inner liner and will assert a force against the insulating panels. Thermal energy in the liquids are further insulated by an insulating lid that is disposed within the upper circumference of the insulating panels and forms an insulating seal with the inner liner. Optionally, the insulating panel rests on an insulating floor that is sized and shaped to fit within the void provided by the lower circumference of the insulating panels

Other optional components can include a plumbing board having inlet and outlet liquid ports for introducing and removing liquid from the insulated storage tank chamber, microprocessors and pumps, temperature sensors, water level sensors and other monitoring systems to regulate the volume and temperature of a liquid in the thermally insulated tank. Also contemplated as an optional feature includes a heat exchanger operable to circulate a liquid, for example, domestic potable water capable of being heated by the stored liquid in the insulated storage tank. The potable water can be used for domestic purposes such as filling a home hot water tank, for use in laundry, for heating the home and other known heating or cooling applications.

DETAILED DESCRIPTION

Referring now to the figures, particularlyFIGS. 1 and 2, the preferred embodiment of the present technology comprising an insulated storage tank10is shown. The insulated storage tank10comprises an outer support jacket30, a plurality of insulating panels100in proximate contact with outer support jacket30, an inner liner400which conforms to the interior cavity of the thermally insulated tank10and an insulating lid20covering the circular opening to the insulated storage tank10. The insulated storage tank10comprises a generally cylindrical-shape. The thin outer support jacket30surrounds the exterior arcuate surface of insulating panels100shown inFIG. 2. The outer support jacket10provides structural rigidity and assists insulating panels100from collapsing or being forced apart. Outer support jacket30has a length that is generally slightly longer than the circumference of the insulated storage tank10. The outer support jacket30has a height that is typically the same height of insulated storage tank10. The outer support jacket30can be made from any structurally resilient polymer, plastic, metal or wood, including for example thermoplastic polyolefin (TPO) materials commercially available as SEQUEL E3000 sold by Solvay Engineered Polymers Inc. (Auburn Hills, Mich., USA),

In some embodiments the outer support jacket30can have a width ranging from about 0.1 mm about 10 mm wide, or from about 1 mm to about 10 mm, or from about 2 mm to about 10 mm, or from about 0.1 mm to about 9 mm, or from about 0.1 mm to about 7 mm, or from about 0.1 mm to about 5 mm. The ends35of the outer support jacket30can be overlaid and glued together around the insulating panels100as shown inFIG. 1.

In some embodiments, the insulated storage tank10includes an insulating lid20. Insulating lid20can be made from any generally known insulation material including expanded polypropylene, thermosetting plastic foams, thermoplastic polyolefins, fiberglass, expanded perlite, wood, metals and any material that is capable of retaining the heat or cold in the liquids within the insulated storage tank10. Foam is preferably used because of the superior heat transfer properties provided by foam materials, relative ease of manufacture and it's lightweight. As shown inFIGS. 1 and 2, the insulating lid20can be apportioned along a midline80in two sections to allow the opening and removal of one half of the lid while keeping the other half in place.

The insulating lid20can optionally house, support and integrate a variety of mechanical and electrical components that provide diagnostic and operational functionality to the insulated storage tank10. For example, insulating lid20can be mounted with a plumbing board to provide all of the hydraulic operational requirements of the tank, for example, liquid input and output and sampling. Control unit60can also include a variety of mechanical and electrical components such as logic boards, relays, microprocessors and the like to send and receive electrical signals to and from a variety of mechanical and electrical components, for example, pumps and sensors. A variety of sensors can be included and mounted onto insulating lid20, for example, water level sensor75mounted to the lid with the aid of a seal70. Water level sensor75can be free-standing or can be integrated with control unit60and a pump (not shown) to determine the level of liquid in the insulated storage tank10. Upon liquid volume loss in the insulated storage tank10, liquid level sensor75can detect the deficiency and send a signal to control unit60to activate a pump to fill the tank with more liquid. Temperature sensor65can also be integrated with control unit60and measure the temperature of the liquid in the insulated storage tank10.

If the liquid in the insulated storage tank10falls below a predetermined threshold, temperature sensor65can send a signal to a valve (not shown) to reduce the volume of liquid being recirculated on the roof of a residence from entering into the insulated storage tank10. Alternatively, the temperature sensor65can alert the system if the liquid in the insulated storage tank10rises above a predetermined threshold. In such a case, the temperature sensor65can send a signal to a pump (not shown) to increase the flow of a secondary liquid being circulated in a heat exchanger (not shown) which is placed in the insulated storage tank10to extract heat from the liquid in the insulated storage tank10. In addition, liquid inlet50and liquid outlet55can be used to add materials into the insulated storage tank10, or to remove materials, including liquids, within the insulated storage tank10. Generally, insulating lid20has a diameter that is slightly larger than the internal diameter500shown inFIG. 8. The thickness of insulating lid20can vary and is not critical. However, for aesthetic appeal, the exterior surface of the insulating lid20can be generally flush with the horizontal rim surface110of the insulating panels100shown in greater detail inFIG. 3.

Referring now toFIGS. 3-6and8-10, the insulated storage tank10also includes a plurality of vertical insulating panels100. In some embodiments, the insulating panels100are the cylindrical side walls of the insulated storage tank10that supports the insulating lid20. In use the insulating lid20is placed on the lid resting shelf160. With reference toFIG. 3, illustrating the insulating panel100in perspective view, the insulating panel100has a rim and a horizontal rim surface110, the rim also includes a rim side wall170and lid resting shelf160. Insulating panel100has a leading edge contact surface140and a trailing edge contact surface150. The insulating floor25is slotted into the recess formed by floor contact wall180and floor support shelf185. When the complete cylinder is formed by aligning all of the required insulating panels100as shown inFIGS. 9 and 10along with the insulating floor25, the inner liner400can be placed in the void created by the arrangement of the insulating panels100and insulating floor25as shown inFIG. 9. The inner liner400rests against and is supported by interior arcuate surface130of insulating panel100.

Insulating panel100has a leading edge contact surface140forms a leading edge apex142with a trailing edge offset210. The placement of the leading edge contact surface140of one insulating panel100in direct contact with the trailing edge contact surface150of the next insulating panel100in succession (in a clock wise fashion) has been surprisingly found to provide substantial resistance to radial movement of the insulating panels due to the hydrostatic force created by liquid. All of the insulating panels100can be connected with the use of a clasping mechanism placed on the exterior arcuate surface120. Alternatively, the leading edge contact surface140and the trailing edge contact surface150of insulating panels100can each have male and female interlocking structure that can approximate the two contact surfaces140and150and lock them into position. Preferably, the insulating panel100can all be clasped or structurally held in position by placing an outer support jacket30around the exterior arcuate surface120as shown inFIGS. 1 and 9.

It has been determined that for a 60 inch outer diameter/350 gallon insulated storage tank10, the pressure exerted on a 1 mm thick TPO outer support jacket30after the insulated storage tank10has been fully assembled having an insulating panel thickness of 4.4 inches, and an inner liner400storing 330 gal of water, 1 m high column of water, inner tank radius of 25.6 inches) is approximately 1084 psi which is well within its tensile yield of 3100 psi. For a 2000 gallon tank with a 2 mm thick TPO outer support jacket using the same column water height but an inner radius of 61.1 inches, the stress on the outer support jacket30is approximately 1184.5 psi and is also well within its tensile yield of 3100 psi.

The insulating panel100can also be made of any suitable modular material as described above for the insulating lid20. These can include expanded polypropylene, thermosetting plastic foams, thermoplastic polyolefins, fiberglass, expanded perlite, wood, metals and any material that is capable of retaining the heat or cold in the liquids within the insulated storage tank10. Foam is preferably used because of the superior heat transfer properties provided by foam materials, relative ease of manufacture and is lightweight. The dimensions of the insulating panel100can vary according to the size of the insulated storage tank10needed. For example, for a 330 gallon insulated storage tank, 5 insulating panels100can be used form a complete cylinder. For a 330 gallon insulated storage tank10, each insulating panel100can measure approximately 47 inches in height, an arcuate length of 34.5 inches and a width of approximately 4 inches. In some embodiments, the number of insulating panels100used to form the insulated storage tank10can vary, preferably there are 5 insulating panel100per insulated storage tank10.

In some embodiments of the present technology, the insulated storage tank10can also optionally have an insulating floor25. While not essential to the practice of the present technology, an insulating floor25can be used with the bottom cutout in the insulating panel100to provide a unified structure that is configured to resist the hydrostatic stresses imposed on the insulated storage tank100walls. As illustrated inFIGS. 7 and 8, the insulating floor25can be made from any insulation material as described above for the insulating panel100. Insulating floor25can be a single piece of insulation or it can be made from two halves divided by the line82as shown inFIG. 7.

Best shown inFIG. 8, the inner liner400can be constructed from any synthetic or natural material that is capable of withstanding liquids having temperatures ranging from about 0° C. to about 250° C., preferably from about 4° C. to about 190° C. In some embodiments, the inner liner400can be constructed of a synthetic plastic material, polymer material or thermoplastic materials capable of withstanding liquid temperatures ranging from about 0° C. to about 250° C. In some embodiments, the inner liner400can be made from a poly vinyl chloride material.

With general reference now toFIGS. 9A-9Gand10, and with specific reference toFIG. 9A, the insulated storage tank10can be prepacked on a pallet182saving transportation costs and freight charges. The small footprint of the delivery package containing the modular insulated storage tank also affords vastly improved maneuverability and locations for installation. As shown inFIG. 9B, the modular parts of the insulated storage tank10can be easily assembled by first preparing the insulating floor25. As previously noted, the insulating floor25is not essential to the invention. However, it is preferred to other forms of insulation flooring. As sequentially shown inFIGS. 9C-9E, the insulating panels150are fitted with floor contact walls180and floor support shelves185; then, the insulating panel100can be slotted into position adjacent and on top of insulating floor25. Then, as shown inFIGS. 9C-9E, all of the insulating panels100are placed around the floor25, ensuring that the leading edge contact surface140and a trailing edge contact surface150of insulating panels100are abutting one another. As shown inFIG. 9F, once the insulating panels100have been positioned around the insulating floor25the next step is to place the inner liner400into the cavity of the insulated storage tank10and leave an overhang402of inner liner400extend over the horizontal rim surface110of the insulating panels100. As shown inFIG. 9G, the last step can include placing an outer support jacket30around the exterior arcuate surface of all of the insulating panels100and joining the ends of the outer support jacket30leaving a joint35as shown inFIG. 1.

The present technology affords a simple manner in which to prepare on site an insulated storage tank having liquid capacities ranging from 50 gallons to 5,000 gallons. The insulated storage tank has many used for storing both hot and cold liquids.

In a preferred embodiment, the hot liquid stored in the insulated storage tank10can include liquids (e.g. water), that are recirculated through a solar thermal capture device, for example, the Power Panel Solar/Thermal capture device disclosed in International Application PCT/US2008/078822, filed Oct. 3, 2008, the disclosure of which is incorporated herein in its entirety. The stored hot liquids (e.g. water) recirculating through said Power Panel Solar/Thermal capture device can reach temperatures ranging from 75-120° C. The stored hot liquid in the insulated storage tank10of the present technology can be used to heat a secondary potable water source (for example a domestic home water source) with the use of heat exchangers placed in the insulated storage tank10. Similarly, heat exchangers placed in insulated storage tanks storing compressed liquids such as carbon dioxide can be used to cool a secondary liquid source for residential or commercial cooling. The rate of recirculation through the solar/thermal energy capture device and passage into the insulated storage tank10can be automated to maintain a set temperature within the insulated storage tank10.

The embodiments and the examples described herein are exemplary and not intended to be limiting in describing the full scope of compositions and methods of the present technology. Equivalent changes, modifications and variations of some embodiments, materials, compositions and methods can be made within the scope of the present technology, with substantially similar results.