Fuel cell cogeneration system

Abstract

A fuel cell cogeneration system comprises a fuel cell, a cooling system for the fuel cell, a heater, a heat utilization portion configured to store heat recovered in the cooling system to allow the heat to be consumed, a detector configured to detect calories remaining in the heat utilization portion, and a controller, wherein the controller determines whether or not the calories remaining in the heat utilization portion are at least not less than the calories required to increase the temperature of the fuel cell to the operating temperature, and based on determination, increases the temperature of the fuel cell to the operating temperature by supplying the remaining calories to the fuel cell through the cooling system and/or by heating the cooling water in the cooling system by the heater.

1 . A fuel cell cogeneration system comprising: 
 a fuel cell;    a cooling system configured to circulate an internal heat transfer medium to allow said fuel cell to exchange heat with the internal heat transfer medium;    a heater configured to heat the internal heat transfer medium;    a heat utilization portion configured to store an external heat transfer medium to allow consumers to consume the external heat transfer medium;    a heat utilization system configured to circulate the external heat transfer medium through said heat utilization portion to allow the internal heat transfer medium in said cooling system to exchange heat with the external heat transfer medium;    a first detector configured to detect remaining calories in said heat utilization portion; and    a controller, wherein at start of said fuel cell,    said controller determines whether or not the detected remaining calories in said heat utilization portion are not less than a threshold which is not less than fuel cell temperature increasing calories required to increase a temperature of said fuel cell to an operating temperature,    determines a ratio between a first temperature increasing operation and a second temperature increasing operation based on determination as to whether or not the detected remaining calories are not less than the threshold, the first temperature increasing operation being performed in such a manner that the remaining calories in said heat utilization portion are transferred to the internal heat transfer medium by heat exchange to increase the temperature of said fuel cell, and the second temperature increasing operation being performed in such a manner that said heater heats the internal heat transfer medium to increase the temperature of said fuel cell, and increases the temperature of said fuel cell to the operating temperature by both the first temperature increasing operation and the second temperature increasing operation or by either the first temperature increasing operation or the second temperature increasing operation.    
     
     
         2 . The fuel cell cogeneration system according to  claim 1 , wherein 
 said controller increases the temperature of said fuel cell to the operating temperature mainly by the first temperature increasing operation when the remaining calories are not less than the threshold, and    increases the temperature of said fuel cell to the operating temperature mainly by the second temperature increasing operation when the remaining calories are less than the threshold.    
     
     
         3 . The fuel cell cogeneration system according to  claim 1 , further comprising: 
 a second detector configured to detect a temperature of the external heat transfer medium stored in said heat utilization portion, wherein    said controller increases the temperature of said fuel cell to the operating temperature mainly by the second temperature increasing operation when the remaining calories are less than the threshold, and    said controller determines whether or not the detected temperature of the external heat transfer medium is not lower than the operating temperature when the remaining calories are not less than the threshold, determines the ratio between the first temperature increasing operation and the second temperature increasing operation based on determination as to whether or not the detected temperature is not higher than the operating temperature, and increases the temperature of said fuel cell to the operating temperature by both the first temperature increasing operation and the second temperature increasing operation or by either the first temperature increasing operation or the second temperature increasing operation.    
     
     
         4 . The fuel cell cogeneration system according to  claim 3 , wherein 
 said controller increases the temperature of said fuel cell to the operating temperature mainly by the first temperature increasing operation when the temperature of the external heat transfer medium is not lower than the operating temperature, and    increases the temperature of said fuel cell to the operating temperature mainly by the second temperature increasing operation when the temperature of the external heat transfer medium is lower than the operating temperature.    
     
     
         5 . The fuel cell cogeneration system according to  claim 1 , further comprising: 
 a third detector configured to detect ambient air temperature outside said fuel cell, wherein    said controller increases the temperature of said fuel cell to the operating temperature mainly by the first temperature increasing operation when the temperature of the external heat transfer medium is not lower than the operating temperature, and    said controller determines whether or not the temperature of the external heat transfer medium is not lower than the detected ambient air temperature when the temperature of the external heat transfer medium is lower than the operating temperature, determines the ratio between the first temperature increasing operation and the second temperature increasing operation based on determination as to whether or not the temperature of the external heat transfer medium is not lower than the detected ambient air temperature, and increases the temperature of said fuel cell by both the first temperature increasing operation and the second temperature increasing operation or by either the first temperature increasing operation or the second temperature increasing operation.    
     
     
         6 . The fuel cell cogeneration system according to  claim 5 , wherein said controller increases the temperature of said fuel cell to the operating temperature by using a combination of the first temperature increasing operation and the second temperature increasing operation when the temperature of the external heat transfer medium is not lower than the detected ambient air temperature, and 
 increases the temperature of said fuel cell to the operating temperature mainly by the second temperature increasing operation when the temperature of the external heat transfer medium is lower than the detected ambient air temperature.    
     
     
         7 . The fuel cell cogeneration system according to  claim 1 , wherein the threshold includes the fuel cell increasing calories and predetermined calories, and 
 said controller increases the temperature of said fuel cell to the operating temperature mainly by the first temperature increasing operation when the remaining calories are not less than the threshold, and    said controller increases the temperature of said fuel cell to the operating temperature mainly by the second temperature increasing operation when the remaining calories are less than the threshold.    
     
     
         8 . The fuel cell cogeneration system according to  claim 7 , wherein the predetermined calories are start time period consumed calories assumed to be consumed by consumers during a start time period from when said fuel cell starts until a predetermined time elapses.  
     
     
         9 . The fuel cell cogeneration system according to  claim 8 , further comprising: 
 a fourth detector configured to detect consumed calories of the external heat transfer medium stored in said heat utilization portion;    a clock configured to measure time; and    a storage configured to store the detected consumed calories and the measured time, wherein    said controller calculates the start time period consumed calories based on the measured time and the stored consumed calories.    
     
     
         10 . The fuel cell cogeneration system according to  claim 9 , wherein said controller obtains the start time period consumed calories by calculating an average value of consumed calories for a predetermined period.  
     
     
         11 . The fuel cell cogeneration system according to  claim 9 , wherein 
 the predetermined calories include a fixed amount and a correction amount, and    said controller changes the correction amount based on the calculated start time period consumed calories.    
     
     
         12 . The fuel cell cogeneration system according to  claim 7 , further comprising: 
 a fifth detector configured to detect ambient air temperature outside said fuel cell, wherein    said controller changes the predetermined calories based on the detected ambient air temperature.    
     
     
         13 . The fuel cell cogeneration system according to  claim 7 , further comprising: 
 a sixth detector configured to detect a temperature of the consumed external heat transfer medium, wherein    said controller changes the predetermined calories according to a frequency at which the detected temperature of the consumed external heat transfer medium is not higher than a predetermined value.    
     
     
         14 . The fuel cell cogeneration system according to  claim 1 , wherein the external heat transfer medium is water, and said heat utilization portion is a tank.  
     
     
         15 . The fuel cell cogeneration system according to  claim 14 , wherein the tank is a layered hotwater tank.  
     
     
         16 . The fuel cell cogeneration system according to  claim 2 , wherein said controller increases the temperature of said fuel cell to the operating temperature only by the first temperature increasing operation when the remaining calories are not less than the threshold, and increases the temperature of said fuel cell to the operating temperature only by the second temperature increasing operation when the remaining calories are less than the threshold.