Water storage tank with passive enhanced thermal energy management and resistance

Abstract

A water storage tank with passive enhanced thermal energy management is provided. The tank is formed of substantially cylindrical central section comprising a majority of the length along its axis and a dome-shaped section at each end, A first system of managing energy management includes providing insulation covering all or most of the tank in order to prevent heat flow energy leaving the tank. The strength of the insulation, is varied such that one end of the tank has less insulativity than the other end of the tank. Preferably change occurs gradually along the axial length of the tank. The second system for providing passive energy management is using insulation formed of a material that has a glass phase change temperature at or near the temperature of the water when it enters the tank. In order for the temperature of the water in the tank to change from the initial temperature it must first cause the insulation to make that glass phase change in order to either heat up or cool down from its initial temperature point. By varying the mass or thickness of the glass phase insulation along the axial length of the tank the amount of passive energy resistance to change varies thereby causing desired convection currents that serve to maintain a constant temperature within the tank thereby slowing any change of temperature at minimum cost.

What is claimed is: 
     
         1 . A double diaphragm tank with passive thermal management for the storage of water at temperatures up to 150° C., while avoiding the use of active heating or cooling means, the tank comprising a central, substantially cylindrical housing section  1 , joined at two circumferential locations  2  and  22  to an upper and a lower dome-shaped housing sections, and within the tank housing sections, and secured to the inner circumferential surface of the cylindrical housing section is a rigid diaphragm, and a flexible diaphragm, the upper circumferential rim of the rigid diaphragm being secured to the inner surface of the central housing section and the flexible diaphragm being sealingly secured to the upper rim, and circumferentially, internally of the rigid diaphragm, by a removable circumferential clip; and
 an insulation layer surrounding the housing sections; 
 there being operatively connected to the bottom of the tank, and extending through the bottom of the rigid diaphragm, a water inlet pipe; and operatively connected to and extending through the top of the tank is a pressure relief valve; 
 the improvement comprising, varying the insulative effectiveness of the insulation layer, axially along the central housing section  1 , so that the either the upper or lower dome-shaped housing sections are covered with a less effective insulation layer, so as to create an internal temperature gradient in any water held in the tank, so as to create convective mixing currents in such water within the tank, when the water is at a temperature different from the ambient temperature exterior of the tank. 
 
     
     
         2 . The double diaphragm tank of  claim 1 , wherein the insulative effectiveness of the insulation layer is varied by providing a sealed insulation and varying the width of the air gaps within portions of the insulation layer. 
     
     
         3 . The double diaphragm tank of  claim 1 , wherein the insulative effectiveness of the insulation layer is varied by changing the thickness of the insulation layer. 
     
     
         4 . The double diaphragm tank of  claim 1 , extending vertically, wherein the insulative effectiveness of the insulation layer is varied such that the Kvalue of the insulation layer in one of the upper or lower dome sections is at least 10% greater than the insulation in the rest of the tank, intended to create convective currents in water in the tank to improve temperature distribution in the water and to prevent fouling of the internal surfaces of the tank. 
     
     
         5 . A double diaphragm tank with passive thermal management for the storage of water at temperatures up to 250° F., while avoiding the use of active heating or cooling means, the tank comprising a central, substantially cylindrical housing section  1 , joined at two circumferential locations  2  and  22  to an upper and a lower dome-shaped housing sections, and within the tank housing sections, and secured to the inner circumferential surface of the cylindrical housing section is a rigid diaphragm, and a flexible diaphragm, the upper circumferential rim of the rigid diaphragm being secured to the inner surface of the central housing section and the flexible diaphragm being sealingly secured to the upper rim, and circumferentially internally of, the rigid diaphragm by a removable circumferential clip; and an insulation layer surrounding the housing sections; there being operatively connected to the bottom of the tank and extending through the bottom of the rigid diaphragm is a water inlet pipe, and operatively connected to and extending through the top of the tank is a pressure relief valve; the improvement comprising securing to the housing sections a layer of insulating material having a glass transition temperature not greater than the desired temperature of the water in the tank, in order to maintain the temperature of the tank near the glass transition temperature. 
     
     
         6 . The double diaphragm tank of  claim 4 , wherein the insulative effectiveness of the insulation layer is varied by varying the quantity of the glass phase transition material within the insulation layer. 
     
     
         7 . The double diaphragm tank of  claim 4 , wherein the insulative effectiveness of the insulation layer is varied by varying the thickness of the glass phase transition material within the insulation layer. 
     
     
         8 . The double diaphragm tank of  claim 4 , wherein the insulative effectiveness of the insulation layer is varied by varying the spacing of the glass phase transition material insulation layer from the surface of the tank shell.