Thermal storage unit and methods for using the same to heat a fluid

Abstract

A thermal storage unit having at least one annular flow channel formed between an inner and outer member is provided. The thermal storage unit uses conventional mill products to create annular flow channels that are coupled to each other via transverse channels for allowing various fluid routing arrangements and piping connections, and that economically maximize the surface area of flow in contact with the thermal mass included in the inner and outer members. This enables the thermal storage unit to economically provide heat storage as well as effective heat delivery and pressure containment for a fluid flowing through the annular channel. The thermal storage unit's size and shape are optimized and its performance enhanced by providing features for maintaining the position of the inner member within the outer member, features for providing support for the unit, and insulation.

1 . A thermal storage unit having a longitudinal axis, the unit comprising: 
 a first annular flow channel disposed about an axis parallel to the longitudinal axis;    a second annular flow channel disposed adjacently to the first annular flow channel about an axis parallel to the longitudinal axis;    a first transverse channel coupling the first and second annular flow channels at a first location along the longitudinal axis that is proximal to an end of the unit;    a third annular flow channel disposed adjacently to the second annular flow channel about an axis parallel to the longitudinal axis; and    a second transverse channel coupling the second and third annular flow channels at a second location along the longitudinal axis that is distal from the end of the unit.    
   
   
       2 . The thermal storage unit of  claim 1  wherein each of the first, second and third transverse channels is perpendicular to the first, second and third annular flow channels.  
   
   
       3 . The thermal storage unit of  claim 1  further comprising: 
 a fourth annular flow channel disposed adjacently to the third annular flow channel about an axis parallel to the longitudinal axis; and    a third transverse channel coupling the third and fourth annular flow channels at a third location along the longitudinal axis that is proximal to the end of the unit.    
   
   
       4 . The thermal storage unit of  claim 3  wherein the first and third transverse channels are parallel to one another and perpendicular to the second transverse channel.  
   
   
       5 . The thermal storage unit of  claim 1  further comprising a fourth transverse channel coupling the first and fourth annular flow channels at a fourth location along the longitudinal axis that is distal from the end of the unit.  
   
   
       6 . The thermal storage unit of  claim 5  wherein each of the first, second, third and fourth transverse channels is perpendicular to the first, second, third and fourth annular flow channels.  
   
   
       7 . The thermal storage unit of  claim 5  wherein the first and third transverse channels are parallel to one another, the second and third transverse channels are parallel to one another and perpendicular to the first and third transverse channels.  
   
   
       8 . The thermal storage unit of  claim 3  wherein the first and second annular flow channels are in fluidic communication with each other through the first transverse channel, the second and third annular flow channels are in fluidic communication with each other through the second transverse channel and the second and third annular flow channels are in fluidic communication with each through the third transverse channel.  
   
   
       9 . The thermal storage unit of  claim 5  wherein the first and second annular flow channels are in fluidic communication with each other through the first transverse channel, the second and third annular flow channels are in fluidic communication with each other through the second transverse channel, the second and third annular flow channels are in fluidic communication with each through the third transverse channel and the third an fourth annular flow channels in fluidic communication with each other through the fourth transverse channel.  
   
   
       10 . A method for using the thermal storage unit of  claim 8 , the method comprising: 
 providing a fluid to thermal storage unit such that: 
 the fluid flows through the first annular flow channel to the first transverse channel,  
 the fluid flows through the first transverse channel to the second annular flow channel,  
 the fluid flows through the second annular flow channel to the second transverse channel,  
 the fluid flows through the second transverse channel to the third annular flow channel,  
 the fluid flows through the third annular flow channel to the third transverse channel, and  
 the fluid flows through the third transverse channel to the fourth annular flow channel; and  
   retrieving the fluid from the thermal storage unit after the fluid has flown through the fourth annular flow channel.    
   
   
       11 . The method of  claim 10  further comprising heating the thermal storage unit using a heat source.  
   
   
       12 . A method for using the thermal storage unit of  claim 9 , the method comprising: 
 providing a fluid to thermal storage unit such that the fluid flows through a first and second path simultaneously, the first path comprising: 
 the fluid flowing through the first annular flow channel to the first transverse channel,  
 the fluid flowing through the first transverse channel to the second annular flow channel, and  
 the fluid flowing through the second annular flow channel to the second transverse channel,  
   the second path comprising: 
 the fluid flowing through fourth transverse channel to the fourth annular flow channel,  
 the fluid flowing through fourth annular flow channel to the third transverse channel, and  
 the fluid flowing through the third transverse channel to the third annular flow channel; and  
   retrieving the fluid from the thermal storage unit after the fluid has flown through the second transverse channel in the first path and after the fluid has flown through the third annular flow channel in the second path.    
   
   
       13 . The method of  claim 12  further comprising heating the thermal storage unit using a heat source.  
   
   
       14 . A method for using the thermal storage unit of  claim 9 , the method comprising: 
 providing a fluid to thermal storage unit such that the fluid flows through a first and second path simultaneously, the first path comprising: 
 the fluid flowing through the first annular flow channel to the first transverse channel, and  
 the fluid flowing through the first transverse channel to the second annular flow channel,  
   the second path comprising: 
 the fluid flowing through fourth transverse channel to the fourth annular flow channel,  
 the fluid flowing through fourth annular flow channel to the third transverse channel,  
 the fluid flowing through the third transverse channel to the third annular flow channel, and  
 the fluid flowing through the third annular flow channel to the second transverse channel; and  
   retrieving the fluid from the thermal storage unit after the fluid has flown through the second annular flow channel in the first path and after the fluid has flown through the second transverse channel in the second path.    
   
   
       15 . The method of  claim 14  further comprising heating the thermal storage unit using a heat source.  
   
   
       16 . A method for adding piping connections to the thermal storage unit of  claim 8  wherein the end of the thermal storage unit is a first end, the thermal storage unit having a second end proximal to the second location, the method comprising: 
 about the second end, coupling a first pipe to the first annular flow channel for providing fluid to the thermal storage unit.    
   
   
       17 . The method of  claim 16  further comprising: 
 about the second end, coupling a second pipe to one of the channels from the group consisting of the second annular flow channel, the third annular flow channel, the fourth annular flow channel and the second transverse channel for retrieving fluid from the thermal storage unit.    
   
   
       18 . The method of  claim 17  further comprising coupling at least one beam to the thermal storage unit about the second end for securing the thermal storage unit to a support structure.  
   
   
       19 . The method of  claim 18  wherein the at least one beam is coupled to the thermal storage unit through one of the fixtures from the group consisting of at least one threaded rod and at least one bushing.  
   
   
       20 . The method of  claim 18  wherein the support structure comprises a plurality of apertures for placing heating rods in order to heat the thermal storage unit.  
   
   
       21 . The method of  claim 18  wherein the support structure comprises insulation material coupled to the thermal storage unit for preventing heat loss from the thermal storage unit.  
   
   
       22 . The method of  claim 21  wherein the insulation material comprises inert ceramic microporous material.  
   
   
       23 . The method of  claim 21  wherein the insulation material is in pressed rigid board form.  
   
   
       24 . The method of  claim 21  wherein the insulation material is in fabric-coated stitched form.  
   
   
       25 . The method of  claim 21  wherein the support structure further comprises an envelope for protecting the insulation material coupled to the thermal storage unit.  
   
   
       26 . A method for adding piping connections to the thermal storage unit of  claim 9  wherein the end of the thermal storage unit is a first end, the thermal storage unit having a second end proximal to the second and fourth locations, the method comprising: 
 about the second end, coupling a first pipe to one of the channels from the group consisting of the first annular flow channel and the second transverse channel for providing fluid to the thermal storage unit.    
   
   
       27 . The method of  claim 26  further comprising: 
 about the second end, coupling a second pipe to one of the channels from the group consisting of the second annular flow channel, the third annular flow channel, the fourth annular flow channel, the second transverse channel and the fourth transverse channel for retrieving fluid from the thermal storage unit.    
   
   
       28 . The method of  claim 27  further comprising coupling at least one beam to the thermal storage unit about the second end for securing the thermal storage unit to a support structure.  
   
   
       29 . The method of  claim 28  wherein the at least one beam is coupled to the thermal storage unit through one of the fixtures from the group consisting of at least one threaded rod and at least one bushing.  
   
   
       30 . The method of  claim 28  wherein the support structure comprises a plurality of apertures for placing heating rods in order to heat the thermal storage unit.  
   
   
       31 . The method of  claim 28  wherein the support structure comprises insulation material coupled to the thermal storage unit for preventing heat loss from the thermal storage unit.  
   
   
       32 . The method of  claim 31  wherein the insulation material comprises inert ceramic microporous material.  
   
   
       33 . The method of  claim 31  wherein the insulation material is in pressed rigid board form.  
   
   
       34 . The method of  claim 31  wherein the insulation material is in fabric-coated stitched form.  
   
   
       35 . The method of  claim 31  wherein the support structure further comprises an envelope for protecting the insulation material coupled to the thermal storage unit.  
   
   
       36 . A backup energy system comprising: 
 the thermal storage unit of  claim 1  for heating a fluid;    a turbine coupled to the thermal storage unit for receiving the heated fluid, the received heated fluid driving the turbine; and    an electrical generator for providing power when the turbine is driven by the heated fluid.    
   
   
       37 . The backup energy system of  claim 36  further comprising: 
 a heating system for heating the thermal storage unit; and    means for maintaining the thermal storage unit at a predetermined temperature.    
   
   
       38 . The backup energy system of  claim 36  wherein the fluid is compressed air, the system further comprising a storage tank containing compressed air for providing the compressed air to the thermal storage unit.  
   
   
       39 . The backup energy system of  claim 38  further comprising: 
 a storage tank containing an inert gas for purging the compressed air in the thermal storage unit; and    a valve coupled to the storage tank for providing the inert gas to the thermal storage unit.    
   
   
       40 . The backup energy system of  claim 39  wherein the inert gas is a inert gas that is heavier than air.  
   
   
       41 . The backup energy system of  claim 39  wherein the inert gas is argon.  
   
   
       42 . A thermal storage unit comprising: 
 at least two annular flow channels disposed adjacently to one another, each annular flow channel being formed between an inner cylindrical surface of a single first member and an outer cylindrical surface of a second member, the outer cylindrical surface having a diameter smaller than the inner cylindrical surface; and    a transverse member coupling the at least two annular flow channels to each other such that they are in fluidic communication with one another.    
   
   
       43 . The thermal storage unit of  claim 42 , the thermal storage unit having a longitudinal axis, each annular flow channel being disposed parallel to the unit's longitudinal axis.  
   
   
       44 . The thermal storage unit of  claim 43  wherein the transverse member is perpendicular to the unit's longitudinal axis.  
   
   
       45 . The thermal storage unit of  claim 43  wherein each one of the second members has a longitudinal axis, at least one second member being disposed such that its longitudinal axis is parallel to the unit's longitudinal axis.  
   
   
       46 . The thermal storage unit of  claim 45  wherein the at least one of the second members is positioned such that it does not come in contact with the first member.  
   
   
       47 . The thermal storage unit of  claim 45  wherein the at least one of the second members is positioned such that it comes in contact with the first member.  
   
   
       48 . The thermal storage unit of  claim 43  wherein each one of the second members has a longitudinal axis, at least one second member being disposed such that its longitudinal axis is not parallel to the unit's longitudinal axis.  
   
   
       49 . The thermal storage unit of  claim 48  wherein the at least one of the second members is positioned such that it comes in contact with the first member.  
   
   
       50 . The thermal storage unit of  claim 43  wherein movement of at least one of the second members in a direction transverse to the unit's longitudinal axis is restricted through a fixture coupled to the least one of the second members.  
   
   
       51 . The thermal storage unit of  claim 43  wherein movement of at least one of the second members in a direction parallel to the unit's longitudinal axis is restricted through a fixture coupled to the least one of the second members.  
   
   
       52 . The thermal storage unit of  claim 42  wherein at least a portion is removed from at least one of the second members.  
   
   
       53 . A method for fabricating the thermal storage unit of  claim 42 , the method comprising: 
 creating a plurality of holes in a block of solid material to form the first member and the transverse member; and    inserting the second members into the first member to form the at least two annular flow channels.    
   
   
       54 . The method of  claim 53  wherein each of the block of solid material and the second members comprises thermal storage material.  
   
   
       55 . The method of  claim 54  wherein the thermal storage material is constructed from one of the materials from the group consisting of iron, aluminum and steel.  
   
   
       56 . The method of  claim 53  further comprising sealing the plurality of holes with a plurality of plugs wherein a first plug is drilled to form an inlet for providing a fluid to the thermal storage unit and wherein a second plug is drilled to form an outlet for retrieving the fluid from the thermal storage unit.  
   
   
       57 . A method for adding piping connections to the thermal storage unit of  claim 42 , the method comprising: 
 coupling a first pipe to a first one of the at least two annular flow channels for providing fluid to the first one of the at least two annular flow channels; and    coupling a second pipe to a second one of the at least two annular flow channels for retrieving fluid from the second one of the at least two annular flow channels.    
   
   
       58 . A backup energy system comprising: 
 the thermal storage unit of  claim 42  for heating a fluid;    a turbine coupled to the thermal storage unit for receiving the heated fluid, the received heated fluid driving the turbine; and    an electrical generator for providing power when the turbine is driven by the heated fluid.    
   
   
       59 . The backup energy system of  claim 58  further comprising: 
 a heating system for heating the thermal storage unit; and    means for maintaining the thermal storage unit at a predetermined temperature.    
   
   
       60 . The backup energy system of  claim 58  wherein the fluid is compressed air, the system further comprising a storage tank containing compressed air for providing the compressed air to the thermal storage unit.  
   
   
       61 . The backup energy system of  claim 60  further comprising: 
 a storage tank containing an inert gas for purging the compressed air in the thermal storage unit; and    a valve coupled to the storage tank for providing the inert gas to the thermal storage unit.    
   
   
       62 . The backup energy system of  claim 61  wherein the inert gas is a inert gas that is heavier than air.  
   
   
       63 . The backup energy system of  claim 61  wherein the inert gas is argon.