System and method for maintaining fluid temperature stability by managing thermal conductivity

Abstract

A system is provided for heating a fluid in one or more cells, each including an electrode pair. The cells are arranged along a flow path, and a controller is configured to regulate the flow of the fluid from an inlet to the cells, determine at a first cell the electrical and thermal conductivity of the fluid, determine from the electrical conductivity a voltage to apply from a power source across the electrode pairs at a current sufficient to heat the fluid, pass the current from the electrode pairs to the fluid to produce the heated fluid, and determine a voltage to apply from the power source across the electrode pairs at a current sufficient to heat the fluid in a second cell based on the thermal conductivity of the fluid in the first cell. Related methods are also disclosed.

1 . A system for heating a fluid, the system comprising:
 two or more cells for retaining a fluid, each cell including one or more electrode pairs positioned therein;   the two or more cells arranged along a flow path including an inlet to and an outlet from the two or more cells;   a controller configured to:
 regulate the flow of the fluid from the inlet to the two or more cells; 
 determine at a first cell of the two or more cells, the electrical conductivity of the fluid; 
 determine at the first cell of the two or more cells, the thermal conductivity of the fluid therein; 
 determine from the electrical conductivity of the fluid a voltage to apply from a power source across the one or more electrode pairs at a current sufficient to heat the fluid in the first cell of the two or more cells; 
 pass the current from the one or more electrode pairs to the fluid to produce a heated fluid in the first cell of the two or more cells; and 
 determine a voltage to apply from the power source across the one or more electrode pairs at a current sufficient to heat the fluid in a second cell of the two or more cells based at least in part on the thermal conductivity of the fluid in the first cell of the two or more cells. 
   
     
     
         2 . The system of  claim 1 , wherein the controller is further configured to determine the electrical conductivity of the fluid and thereby determine the voltage to apply across the one or more electrode pairs continuously. 
     
     
         3 . The system of  claim 1 , wherein the one or more electrode pairs are segmented into two or more segments, each segment being configured to individually apply voltage by the controller. 
     
     
         4 . The system of  claim 3 , wherein individually applying the voltage across the two or more segments increases or decreases the effective electric current drawn by the fluid by virtue of electrode surface area. 
     
     
         5 . The system of  claim 3 , wherein the two or more segments are of uniform size. 
     
     
         6 . The system of  claim 3 , wherein the two or more segments are of different sizes. 
     
     
         7 . The system of  claim 6 , wherein the one or more electrode pairs are segmented into n segments each having effective surface areas in a ratio of 1:2: . . . :2 (n-1) . 
     
     
         8 . The system of  claim 1 , wherein the one or more electrode pairs are substantially parallel and positioned in a generally horizontal plane relative to the flow path. 
     
     
         9 . The system of  claim 1 , wherein the one or more electrode pairs are substantially vertical and positioned in a generally vertical plane relative to the flow path. 
     
     
         10 . The system of  claim 1 , wherein the one or more electrode pairs are at least in part coated with an inert electrically conductive material or a non-metallic electrically conductive material including an electrically conductive plastics material, carbon impregnated material, and combinations thereof. 
     
     
         11 . The system of  claim 1 , wherein the one or more electrode pairs are formed at least in part from a material selected from the group consisting of metal or a non-metallic electrically conductive material. 
     
     
         12 . The system of  claim 1 , wherein the one or more electrode pairs are formed from an electrically conductive, inert material including graphite, carbon, and combinations thereof. 
     
     
         13 . The system of  claim 1 , wherein the controller is further configured to measure a flow rate of the fluid flowing through the flow path. 
     
     
         14 . The system of  claim 13 , wherein the controller is further configured to increase or decrease the flow rate of the fluid flowing through flow path to regulate a residency time of the fluid in the two or more cells. 
     
     
         15 . The system of  claim 1 , wherein the controller is further configured to measure a temperature of the fluid flowing through the flow path. 
     
     
         16 . The system of  claim 15 , wherein the controller is further configured to measure the temperature of the fluid at the inlet and outlet; and
 provide the temperature as feedback to a temperature controller configured to increase or reduce heating of the fluid.   
     
     
         17 . The system of  claim 1 , wherein the two or more one or more cells are serially arranged along the flow path. 
     
     
         18 . The system of  claim 1 , wherein the controller is further configured not to apply the voltage across the one or more electrode pairs if the electrical conductivity of the fluid falls outside a predetermined range. 
     
     
         19 . The system of  claim 1 , wherein the inlet and outlet extend at substantially one hundred and eighty degrees to each other. 
     
     
         20 . The system of  claim 1 , wherein the two or more cells for retaining a fluid are made from an electrically non-conductive light weight plastic material. 
     
     
         21 . The system of  claim 1 , wherein the thermal conductivity of the fluid is determined from at least fluid temperature and cell dimensions. 
     
     
         22 . The system of  claim 21 , wherein the dimensions include a respective height and a respective width of the cell. 
     
     
         23 . The system of  claim 1 , including n cells for retaining a fluid, each cell including one or more electrode pairs positioned therein; and
 the n cells arranged along a flow path including an inlet to and an outlet from the n cells.   
     
     
         24 . A method for heating a fluid, the method comprising the steps of:
 providing two or more cells for retaining a fluid, each cell including one or more electrode pairs positioned therein;   arranging the two or more cells along a flow path, the flow path including an inlet to and an outlet from the two or more cells;   determining at the first cell of the two or more cells, the electrical conductivity of the fluid;   determining at the first cell of the two or more cells, the thermal conductivity of the fluid therein;   determining from the electrical conductivity of the fluid a voltage to apply from an external power source, across the one or more electrode pairs at a current sufficient to heat the fluid in the first cell of the two or more cells;   passing the current from the one or more electrode pairs to the fluid to produce a heated fluid in the first cell of the two or more cells; and   determining a voltage to apply from the power source across the one or more electrode pairs at a current sufficient to heat the fluid in a second cell of the two or more cells based at least in part on the thermal conductivity of the fluid in the first cell of the two or more cells.   
     
     
         25 . The method of  claim 24 , wherein the controller is further configured to determine the electrical conductivity of the fluid and thereby determine the voltage to apply across the one or more electrode pairs continuously. 
     
     
         26 . The method of  claim 24 , wherein the one or more electrode pairs are segmented into two or more segments, each segment being configured to individually apply voltage by the controller. 
     
     
         27 . The method of  claim 26 , wherein individually applying the voltage across the two or more segments increases or decreases the effective electric current drawn by the fluid by virtue of electrode surface area. 
     
     
         28 . The method of  claim 26 , wherein the two or more segments are of uniform size. 
     
     
         29 . The method of  claim 26 , wherein the two or more segments are of different sizes. 
     
     
         30 . The method of  claim 29 , wherein the one or more electrode pairs are segmented into n segments each having effective surface areas in a ratio of 1:2: . . . :2 (n-1) . 
     
     
         31 . The method of  claim 24 , wherein the one or more electrode pairs are substantially parallel and positioned in a generally horizontal plane relative to the flow path. 
     
     
         32 . The method of  claim 24 , wherein the one or more electrode pairs are substantially vertical and positioned in a generally vertical plane relative to the flow path. 
     
     
         33 . The method of any  claim 24 , wherein the one or more electrode pairs are at least in part coated with an inert electrically conductive material or a non-metallic electrically conductive material including an electrically conductive plastics material, carbon impregnated material, and combinations thereof. 
     
     
         34 . The method of  claim 24 , wherein the one or more electrode pairs are formed at least in part from a material selected from the group consisting of metal or a non-metallic electrically conductive material. 
     
     
         35 . The method of  claim 24 , wherein the one or more electrode pairs are formed from an electrically conductive, inert material including graphite, carbon, and combinations thereof. 
     
     
         36 . The method of  claim 24 , wherein the controller is further configured to measure a flow rate of the fluid flowing through the flow path. 
     
     
         37 . The method of  claim 36 , wherein the controller is further configured to increase or decrease the flow rate of the fluid flowing through flow path to regulate a residency time of the fluid in the two or more cells. 
     
     
         38 . The method of  claim 24 , wherein the controller is further configured to measure a temperature of the fluid flowing through the flow path. 
     
     
         39 . The method of  claim 38 , wherein the controller is further configured to measure the temperature of the fluid at the inlet and outlet; and
 provide the temperature as feedback to a temperature controller configured to increase or reduce heating of the fluid.   
     
     
         40 . The method of  claim 24 , wherein the two or more one or more cells are serially arranged along the flow path. 
     
     
         41 . The method of  claim 24 , wherein the controller is further configured not to apply the voltage across the one or more electrode pairs if the electrical conductivity of the fluid falls outside a predetermined range. 
     
     
         42 . The method of  claim 24 , wherein the inlet and outlet extend at substantially one hundred and eighty degrees to each other. 
     
     
         43 . The method of  claim 24 , wherein the two or more cells for retaining a fluid are made from an electrically non-conductive light weight plastic material. 
     
     
         44 . The method of  claim 24 , wherein the thermal conductivity of the fluid is determined from at least fluid temperature and cell dimensions. 
     
     
         45 . The system of  claim 44 , wherein the dimensions include a respective height and a respective width of the cell. 
     
     
         46 . The system of  claim 24 , including n cells for retaining a fluid, each cell including one or more electrode pairs positioned therein; and
 the n cells arranged along a flow path including an inlet to and an outlet from the n cells.   
     
     
         47 . A method for heating a fluid, the method comprising the steps of:
 passing a fluid along a flow path from an inlet to an outlet, the flow path including at least first and second cells positioned along the flow path such that the fluid passing the first cell subsequently passes the second cell, each cell including at least one electrode pair between which an electric current is passed through the fluid to produce heat therein during its passage along the flow path, and wherein at least one of the cells includes at least one segmented electrode, the segmented electrode comprising a plurality of electrically separable segments allowing an effective surface area of the segmented electrode to be controlled by selectively activating the segments such that upon application of a voltage to the activated electrode segment(s), current drawn will depend in part upon the effective surface area;   determining the fluid conductivity at the inlet;   determining the thermal conductivity of the fluid in the first cell;   determining from measured fluid conductivity a required voltage and current to be delivered to the fluid by the first cell to raise the temperature of the fluid therein by a first amount;   determining a heated fluid conductivity resulting from operation of the first cell;   determining from the heated fluid conductivity a required voltage and current to be delivered to the fluid by the second cell to raise the temperature of the fluid therein by a second amount based at least in part on the thermal conductivity of the fluid in the first cell; and   activating segments of the segmented electrode in a manner to effect delivery of desired current and voltage by the segmented electrode.