CROSS REFERENCES
The text of this description is the same as that of Irish application number 2010/0455 dated Jul. 21, 2010 by the inventor from which priority is claimed and the references to drawings in this text are references to the drawings in that Irish filing which will be published shortly. The same text & drawings exist in UK application GB 1112474.0 filed on Jul. 20, 2011. Relevant declarations by the inventor will be filed shortly & certified copies of these applications will be provided at the US examination stage.
FIELD OF THE INVENTION
The present invention relates to ice composite bodies for use in the construction of fixed or floating structures located in or on water or on land.
BACKGROUND TO THE INVENTION
Ice composite bodies are well known and are generally formed by loading a natural body of ice with additional frozen water, earth or gravel, until the natural ice body sinks to the seabed. Cutting out a perimeter on the body when grounded enables the body to be separated from the surrounding ice sheet to protect equipment on the body. Examples are SU Patent 1092241 & U.S. Pat. No. 4242012. More complex bodies also use wall elements and artificial refrigeration such as disclosed in U.S. Pat. Nos. 3738114 and 4325656. These ice composite bodies are generally used in arctic locations for oil exploration. Ice composite bodies can also be used in applications such as bridges, breakwaters, causeways, pontoons, artificial islands, building foundations, dams, tidal barrages, wave power barrages, harbor walls, wind power farms, or aircraft runways. GB-A Patent 2071295 discloses an ice composite body consisting of a gravity ice platform with a wider potential range of uses, but made by a process which can result in large quantities of dissolved gases and liquid becoming entrained in the ice, resulting in a tendency for the ice to be unstable under stress, deform & creep. The inventor's prior patent EP 1290281 referred to this prior art as disclosed at the time of its issuance in 2005. He disclosed in EP 1290281 an ice composite body and a method for making it which resolved these problems even for use in temperate waters, where the body in use was in an environment with sea temperatures constantly above the melting point of ice. Since then further needs have emerged such as data centers & because of the problems of climate change & of the long term need for sustainable energy sources. As rising sea levels caused by climate change threaten low lying countries such as the Maldives, ice composite bodies can be used to replace land lost to the sea. They can also be used to provide areas offshore to shelter & house equipment & personnel for sustainable energy sources such as Ocean Thermal Energy Conversion (OTEC) or OTEC hybrids with other solar thermal energy technologies, new desalination technologies and new mariculture technologies. These new needs create new demands for technology, which can provide a suitable environment for human life even in hot equatorial climates & perform reliably there for extended periods of time. It is an object of the present invention to provide an ice composite body which can meet these new needs in a particularly effective way.
SUMMARY OF THE INVENTION
The present invention provides an ice composite body comprising a constrained inner ice core, a protective outer armor shell having a base, side sections and a separate top section, means for thermally insulating the ice core and means for maintaining the ice core in a frozen condition in use, with a bitumen, elastomer modified bitumen, plastic film or mastic lining between the ice core and the inner walls of the side & base sections. The top section of the shell, as in EP 1290281, is free to move vertically between the side sections thus distributing the weight of the top section and its burden evenly over the top of the ice core. However in the present invention the ice core does not extend all the way to the bottom of the shell but in use has a permanent layer of liquid water close to but above 0° C. at the base of the shell. The ice core rests hydrostatically on this close to freezing water layer as opposed to litho-statically on the base of the shell as in the case of EP 1,290,281,but with litho-static equilibrium between the ice core and the top section of the armor shell. This layer of water is connected hydraulically at the internal base of the shell by water supply & removal pipes to a water tank. The water level in this tank is controlled by any suitable means such as an ordinary ball-cock system, at the level necessary for the water column to exert upward pressure on the ice core sufficient to support the weight of the top section of the shell, any load placed on the top section of the shell & the ice core, with the lining at the sides & base or the ice core itself, providing a watertight seal at the sides & base. The tank has a water supply to make up any losses and to maintain the desired level in the tank. The water layer also has an expansion connection pipe to the top of the tank & the tank has an overflow connection to drain. This water layer, the water supply, expansion pipe, overflow pipe and the water tank have a means for controlling their temperature at close to but above 0° C. In addition, above this permanent water layer & underneath an upper section of the ice core here called the structural ice core, a lower section of the ice core here called the thermal conditioning ice layer is provided, with a separately controllable means of melting and freezing this thermal conditioning ice layer, characterized in that this means can melt this ice layer from its bottom up & freeze the resultant water layer from the top down but not freeze the permanent water layer. All the while the structural ice core is maintained in the solid state by its refrigeration means & the permanent water layer at the base of the armor shell, which is maintained liquid by its separate heating means, provides a hydraulic connection to the water tank. This hydraulic connection maintains the required pressure in the water layers, which maintains the required hydrostatic upward pressure on the thermal conditioning ice core, which in turn exerts upward litho-static pressure on the structural ice core, which in turn exerts upward litho-static pressure on the top section of the armor shell to support it & any load placed on it.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a transverse section of a first embodiment of an ice composite body according to the invention showing such a body after construction and before formation of its permanent water layer.
FIG. 2 is a transverse section of a first embodiment of an ice composite body according to the invention after formation of the permanent water layer.
FIG. 3 is a transverse section of a first embodiment of an ice composite body according to the invention with the thermal conditioning ice layer melted.
All figures show the piping connecting the water supply, water tank, drains and the ice composite body.
DETAILED DESCRIPTION OF THE DRAWINGS & THE INVENTION
FIG. 1 shows generally at 10 a transverse section through one embodiment of an ice composite body according to the invention. The body 10 has an ice core 11 & 94 and a protective outer armor shell 12. The protective armor shell 12 is preferably made from reinforced concrete sealed on its inside with a watertight sealant such as bitumen or made using waterproof concrete. The protective outer armor shell 12 consists of a base section 13, side sections 14 and a separate top section 15. The top section 15 rests on the ice core 11 and is free to move vertically between the inner walls 16 of the side sections 14. The outer armor shell 12 has an inner wall 16 and an outer wall 17, defining a space 18 between them which acts as a space for thermally insulating the ice cores 11 & 94 or to house equipment. The space 18 is preferably filled with air, or other insulating material (not shown). The amount of insulation used can usefully be varied seasonally to vary the heat flow into the ice composite body from the environment. Strengthening ribs 19 are located at intervals between the inner wall 16 and the outer wall 17. The body 10 has a means 20 & 21 for maintaining the structural ice core 11 in a permanently frozen state consisting of a plurality of refrigeration pipes 20 & 21. The refrigeration pipes 21 pass through the inner walls 16 of the side sections 14 at 23 and are connected by valves 22 to a suitable refrigeration unit (not shown) which may be located in the space 18. The refrigeration pipes 20 & 21 are located in parallel groups at different levels in the structural ice core with alternate levels running at right angles to each other. The refrigeration pipes where they pass through the inner wall 16 at points 23 are fixed to the inner wall by any suitable means. The ice core when made consists of two sections 11 & 90. An upper core 11 here called the structural ice core is always maintained in the frozen state by its refrigeration means 20 & 21. This section of the core is designed to withstand the structural stresses which it is subject to, including by providing litho-static support to the top section 15 of the armor shell. The body 10 also has when constructed a lower ice layer 90 shown in FIG. 1. This ice layer at construction includes the thermal conditioning ice layer 94 and the ice forming the permanent water layer 91 (FIG. 2). It supports the structural ice core above it & when constructed is supported below by the inner wall of the base 13 of the armor shell. After construction & before first use the permanent water layer 91 shown in FIG. 2 is formed by melting part of the lower ice layer 90 by heating means 102. The means used to melt this layer may usefully be temporarily connected to the heating output from the refrigeration system (not shown) used to maintain the structural ice core in a permanently frozen state. This means 102 used to melt & maintain the permanent water layer in liquid form is a piping system similar in form to the pipes 20 & 21. When the body is in use the permanent water layer 91 is maintained permanently in the liquid form close to but above 0° C. During use of the body the means 102 contains a suitable fluid circulated at a temperature of close to but above 0° C. Water from deep ocean layers which is available at temperatures close to 4° C. may usefully constitute the fluid used in means 102. This permanent water layer is connected by a pipe system 93 to a water tank 101 here shown resting on part of the side section 14 of the shell, with a water supply 100 and any suitable level control system such as a ball cock. The water supply is preferably of de-ionized water which has been degassed. This water supply pipe 100, pipe system 93, overflow pipe 99 and water tank 101 are provided with a means such as a jacket (not shown) circulating fluid to maintain them & their water content close to but above 0° C. Water from deep ocean layers which is available at temperatures close to 4° C. may usefully be used in this jacket (not shown). This jacket (not shown) may usefully be insulated. The water level in tank 101 is maintained such that the pressure head of the water within the base of the body equals the pressure exerted by loads (not shown) on the top section of the shell 15, the weight of the top section of the shell, the weight of the structural ice core, the weight of any thermal conditioning ice layer in place, the level of water above the pipe 93 level in the permanent liquid water layer 91 & a safety margin. The safety margin is preferably calculated to be able to meet any variation in use of load on the top section of the shell, while not exerting an upward pre-stressing force in excess of that represented by the resistance to upward movement represented by friction at the sides of the top section of the shell & the structural ice core. The body has a separate means 92 of both heating and refrigerating the thermal conditioning ice layer 94. The means 92 consist of a plurality of pipes 92 which by supplying them with brine above or below the freezing point of water can be used to either melt the thermal conditioning ice layer 94 or freeze the resultant temporary water layer 97. The process of melting to produce this temporary water layer may result in it having particles of ice floating in it. The refrigeration or heating pipes 92 pass through the inner walls 16 of the side sections 14 at points 96 and are connected by valves 95 to any suitable heating or cooling system (not shown) which may be located in the space 18. The pipes 92 are located in parallel groups at different levels in the thermal ice conditioning layer 94, which when melted forms the resultant temporary water layer 97, with pipe groups at alternate levels suitably running at right angles to each other. The heating or refrigeration pipes 92 where they pass through the inner wall 16 at points 96 are sealed to the inner wall by a waterproof seal able to withstand the hydrostatic pressure at that point, using any suitable means. FIG. 2 shows the body after construction and after formation of the permanent water layer 91 with the thermal conditioning ice layer 94 in ice form. FIG. 3 shows the body with the thermal conditioning ice layer 94 in FIG. 2 melted to temporary water layer 97 which is above the permanent water layer 91 made after initial construction and is hydrostatically united with it. The resultant balance of structural forces is that the water pressure of the permanent water layer 91, with any temporary water layer 97, which layers may be augmented by additional make-up water supplied from the tank 101 by pipe 93, supports any thermal conditioning ice layer 94 hydrostatically, which in turn supports the structural ice core 11 litho-statically, which in turn supports the top section 15 of the armor shell litho-statically. The waterproof seal (not shown) on the inner surface of the base and side sections facilitates maintenance of pressure & keeps water usage low. The pre-stressing upwards arising from the calculated safety margin provides for variation in load in use without causing actual vertical movement of the structural ice core by remaining within the limit of friction between the structural ice core 11 and the side walls 16. The separate piping means 92 of melting and freezing the thermal conditioning ice layer can be connected to a suitable refrigeration system, an air conditioning system for a building or other thermal space conditioning need or to a heating system or to a combination of these. When a need exists for cooling a space, such as for example a data center, the connection to the air conditioning system for that space can be used to melt the thermal conditioning ice layer 94 (FIG. 2) to temporary water layer 97 (FIG. 3) & the latent heat of the thermal conditioning layer of ice used to cool the space. The resultant temporary water layer 97 can be refrozen later for example using off peak electricity or when a need for heating arises. When the temporary water layer 97 is frozen by means 92 its volume increases. This increase in volume displaces some water from the permanent water layer which is accommodated by an expansion pipe 98 connected from the internal base of the armor shell to an overflow into the elevated water tank 101. This tank usefully has a safety overflow to drain 99. When an additional structural load is imposed on the top section of the shell, the upward safety margin pre-stressing will reduce, the top section of the shell, the structural ice core and the shell liner may deflect downwards slightly and cause expression of a small additional quantity of water into the elevated water tank 101 or to drain 99. When the thermal conditioning ice layer 94 melts it contracts in volume & the pipe connection 93 from the elevated water tank 101 supplies water to make up this contraction in volume within the water layers within the base of the shell. The volume of this expansion and contraction is about 8% of the volume of the thermal conditioning ice layer used in a cycle. In use this cycle will generally be a cooling need for cooling for air conditioning which is later reversed or replaced by a heating need. Such alternate cooling & heating cycles result in water flowing to and fro between the water layers & the water supply tank over the period of the thermal conditioning cycles. They also result in small pressure variations in water head due to these flows. These volume variations and flow rates are well within the limits for usual water supply & control systems to control & can be controlled by any of these usual means to control & maintain hydrostatic and litho-static equilibrium and structural stability. These water flow control systems may also be used to raise or lower the level of the structural ice core 11 & the top section of the shell 15. For example if after construction of an ice composite body fixed in the sea, sea levels rose more than anticipated, the water supply pipe 93 may also be used to maintain the desired elevation of top section 15 either by raising the elevation of the water tank 10, or by any other suitable equivalent pressurization means (not shown) incorporated into water supply pipe 93. This ice composite body can be used in many structural embodiments either fixed or floating in any water body or on land such as. a shelter pier, bridge, breakwater, causeway, pontoon, artificial island, jetty, building foundation or support, data center, dam, tidal barrage, wave power barrage, harbor wall, wind turbine support, aircraft runway, OTEC equipment support, to protect coastlines from erosion or to replace land lost to the sea. When the body is in use the depth of the permanent water layer 91 can be chosen to be any suitable depth by the design engineer using usual structural, heat exchange and fluid mechanics design principles. For example, in the case of use of a structural ice composite as a building foundation and thermal conditioning means for residential buildings, it can usefully be about 0.25 meters in depth, with the water supply tank 101, typically having a capacity of approximately 80 liters for an average residential unit (not shown) constructed on the top of the top section of the shell. In this embodiment, the combined thermal conditioning ice layer plus permanent water layer when constructed would typically be up to 1.25 meters in height. A useful air conditioning cycle over 4-8 hours in such an embodiment would result in approximately 80 liters of water flowing into and out of the water layers per average residential unit connected to this system. It could also result in a small potential pressure variation of at most about 0.7 centimeters of water head within the water layers at peak makeup flow. These volume variations and flow rates are well within the limits for available water supply & control systems to control & maintain hydrostatic and litho-static equilibrium and structural stability in such an embodiment. This ice composite body can also be used in more demanding thermal conditioning embodiments for air conditioning, such as data centers, including retrofits to data centers on land and including where the peak daytime electricity demand is determined by a peak need for air conditioning for cooling purposes, to shift this demand from daytime peak supply to nighttime off-peak supply with associated additional cost savings. These more demanding applications will be custom designed and their typical features will depend on their scale and individual thermal cycle needs. This ice composite body can also be used in embodiments for heating a space when a demand for heating arises, using the heat from the structural ice core's separate refrigeration system, or from refreezing the temporary water layer, while providing for any desired structural use of the ice composite such as mentioned in the useful embodiments. One embodiment may also have an unusual scientific use. As far as is known this ice composite body is a rare example of an innovation which combines metastable hydrostatic and litho-static equilibrium. A variation of the embodiment cited in which the top section is in two parts along a subduction or horizontal axis and these parts are less constrained along other movement axes, may therefore be useful for simulating & studying tectonic plate movements. These are caused by metastability between the hydrostatics of the liquid level of the earth's core and the litho-statics of the earth's solid crustal oceanic and continental plates. This embodiment of the ice composite body described here may therefore be useful to simulate these & lead to better understanding of such phenomena.
Patent Application
20120020741
