Abstract:
A heat recycling system of fuel cells is provided. The heat recycling system includes: a fuel cell apparatus, a cooling tank, an adsorption refrigerating apparatus, a first set of valve, and a second set of valve. The adsorption refrigerating apparatus has a first adsorption bed, a second adsorption bed, a first evaporator/condenser, and a second evaporator/condenser. The first set of valve connects the fuel cell apparatus and the cooling tank to the first adsorption bed and the second adsorption bed. The second set of valve connects the first evaporator/condenser and the second evaporator/condenser to the cooling tank. Switching of the first and the second sets of valve is controlled by an automatic control system communicating between the fuel cell apparatus, the cooling tank, and the adsorption refrigerating apparatus. Thus, waste heat generated by the fuel cell apparatus is timely brought away, recycled, and reused by the adsorption refrigerating apparatus.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to heat recycling systems of fuel cells and, more particularly, to a heat recycling system of fuel cells for use with the fuel cells. 
         [0003]    2. Description of the Prior Art 
         [0004]    A fuel cell apparatus is a power generation device whereby a fuel (for example, hydrogen, methanol, carbon monoxide, or hydrocarbons) reacts with an oxidizing agent (for example, oxygen) in electrochemical reaction so as to generate electric power. 
         [0005]    Oxygen and hydrogen required for the fuel cell apparatus are provided by a cathode gas source and an anode gas source, respectively, and then the oxygen and the hydrogen undergo electrochemical reaction in the fuel cell apparatus so as to generate electric power. However, in addition to electric power, the electrochemical reaction taking place in the fuel cell apparatus produces a large amount of waste heat. The waste heat which originates in the fuel cell apparatus has to be removed therefrom, so as to keep the fuel cell apparatus at appropriate operating temperature lest the performance of the fuel cell apparatus is compromised. 
         [0006]    In general, upon delivery of a cooling liquid to the fuel cell apparatus, the cooling liquid at relatively low temperature absorbs waste heat from the fuel cell apparatus before being discharged from the fuel cell apparatus together with the waste heat, so as to remove the waste heat from the fuel cell apparatus timely. However, the above-mentioned has a drawback, namely the cooling liquid has to be delivered to the fuel cell apparatus continually. Hence, there is an urgent need to devise a complete fuel cell system in which waste heat from a fuel cell apparatus can be timely removed. 
       SUMMARY OF THE INVENTION 
       [0007]    The present invention provides a heat recycling system of fuel cells wherein a fuel cell apparatus and a cooling tank are coupled to each other via an adsorption refrigerating apparatus so as to form a recycling system whereby waste heat generated by the fuel cell apparatus is timely removed therefrom and recycled for use as a heat source of the adsorption refrigerating apparatus. 
         [0008]    The present invention provides a heat recycling system of fuel cells whereby a fuel cell apparatus is kept at an appropriate operating temperature favorable for electrochemical reaction. 
         [0009]    The present invention provides a heat recycling system of fuel cells whereby integration of an adsorption refrigerating apparatus and an air conditioning apparatus enables electric power to be generated by the fuel cell apparatus and cool air to be produced concurrently. 
         [0010]    To achieve the above and other objectives, the present invention provides a heat recycling system of fuel cells. The system comprises a fuel cell apparatus, a cooling tank, an adsorption refrigerating apparatus, a first set of valve, and a second set of valve. The adsorption refrigerating apparatus has a first chamber and a second chamber. The first chamber is provided with at least a first adsorption bed and a first evaporator/condenser therein. The second chamber is provided with at least a second adsorption bed and a second evaporator/condenser therein. The first set of valve is connected to the fuel cell apparatus, the cooling tank, the first adsorption bed, and the second adsorption bed. The second set of valve is connected to the cooling tank, the first evaporator/condenser, and the second evaporator/condenser. 
         [0011]    The present invention involves at least the following inventive steps: 
         [0012]    1. An adsorption refrigerating apparatus is coupled to a fuel cell apparatus and a cooling tank, so as to form a recycling system for recycling and reusing waste heat generated by the fuel cell apparatus. 
         [0013]    2. An adsorption refrigerating apparatus is coupled to an air conditioning apparatus such that electric power is generated by the fuel cell apparatus and cool air is produced concurrently. 
         [0014]    The following illustrative embodiments describe the features and advantages of the present invention in detail. After reading the disclosure of the specification, the claims, and the drawings, persons skilled in the art can readily comprehend the objectives and advantages of the present invention and implement the present invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]      FIG. 1  is a schematic view of a first preferred embodiment of a heat recycling system of fuel cells according to the present invention; 
           [0016]      FIG. 2  is a schematic view of a second preferred embodiment of the heat recycling system of fuel cells according to the present invention; 
           [0017]      FIG. 3  is a schematic view of a third preferred embodiment of the heat recycling system of fuel cells according to the present invention; and 
           [0018]      FIG. 4  is a schematic view of a fourth preferred embodiment of the heat recycling system of fuel cells according to the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0019]    Referring to  FIG. 1  through  FIG. 4 , in the present preferred embodiment, a heat recycling system  100 ,  100 ′ of fuel cells comprises a fuel cell apparatus  10 , a cooling tank  20 , an adsorption refrigerating apparatus  30 , a first set of valve  40 , and a second set of valve  50 . 
         [0020]    The fuel cell apparatus  10  is a water-cooled fuel cell apparatus or an oil-cooled fuel cell apparatus. The fuel cell apparatus  10  can be of several types according to the electrolyte used, namely a Proton Exchange Membrane Fuel Cell (PEMFC) device, an Alkaline Fuel Cell (AFC) device, a Phosphoric Acid Fuel Cell (PAFC) device, a Solid Oxide Fuel Cell (SOFC) device, or a Molten Carbonate Fuel Cell (MCFC) device, among others. 
         [0021]    The cooling tank  20  stores a cooling liquid. The cooling liquid is cooling water or cooling oil. Since electrochemical reaction in the fuel cell apparatus  10  is exothermic, the cooling liquid is delivered from the cooling tank  20  to the fuel cell apparatus  10 , such that waste heat generated from the fuel cell apparatus  10  is removed therefrom. Consequently, the operating temperature of the fuel cell apparatus  10  is maintained within an appropriate range. 
         [0022]    The adsorption refrigerating apparatus  30  is a solid-state adsorption refrigerating apparatus. The adsorption refrigerating apparatus  30  has a first chamber  31  and a second chamber  32 . The first chamber  31  and the second chamber  32  are vacuum chambers. The first chamber  31  is provided therein with at least a first adsorption bed  311  and a first evaporator/condenser  312 . The second chamber  32  is provided therein with at least a second adsorption bed  321  and a second evaporator/condenser  322 . Each of the first adsorption bed  311  and the second adsorption bed  321  is provided with an adsorbent and a coolant. The adsorbent is a porous material, such as silica gel, molecular sieve, active carbon, activated carbon fiber, calcium chloride, zeolite, foamed metal, or activated aluminum oxide, among others. The coolant is water, methanol, ethanol, or ammonia liquid, among others. 
         [0023]    Alternatively, referring to  FIG. 1  through  FIG. 4 , the adsorption refrigerating apparatus  30  has at least two said first adsorption beds  311  connected in parallel and at least two said second adsorption beds  321  connected in parallel. 
         [0024]    The adsorption refrigerating apparatus  30  operates by interaction between the adsorbent and the coolant and effectuates cooling by evaporation and heat absorption, whose details are presented below. 
         [0025]    At low temperature, the adsorbent in the first adsorption bed  311  or the second adsorption bed  321  adsorbs a large amount of the coolant and allows adsorption to take place. Heat is released whenever the adsorbent adsorbs the coolant, thereby raising the temperature of the cooling liquid passing the first adsorption bed  311  or the second adsorption bed  321 . Afterward, the adsorbent saturated with the coolant is heated up by a heat source so as to release the coolant in gaseous form, that is, desorption. The adsorbent desorbs the coolant by absorbing heat. As a result, the temperature of the cooling liquid passing the first adsorption bed  311  or the second adsorption bed  321  is reduced. 
         [0026]    While adsorption takes place, the first evaporator/condenser  312  or the second evaporator/condenser  322  functions as an evaporator whereby the coolant evaporates (i.e., the coolant is converted from liquid phase into gaseous phase); hence, heat energy of the cooling liquid passing the first evaporator/condenser  312  or the second evaporator/condenser  322  is absorbed so as to decrease the temperature of the cooling liquid, and in consequence cooling is effectuated. However, during desorption, the first evaporator/condenser  312  or the second evaporator/condenser  322  functions as a condenser whereby the coolant condenses (i.e., the coolant is converted from gaseous phase into liquid phase); hence, the cooling liquid passing the first evaporator/condenser  312  or the second evaporator/condenser  322  absorbs heat, and in consequence the temperature of the cooling liquid increases. 
         [0027]    Therefore, desorption which takes place in the adsorption refrigerating apparatus  30  decreases the temperature of the cooling liquid passing the first adsorption bed  311  or the second adsorption bed  321  but increases the temperature of the cooling liquid passing the first evaporator/condenser  312  or the second evaporator/condenser  322 . Conversely, adsorption which takes place in the adsorption refrigerating apparatus  30  increases the temperature of the cooling liquid passing the first adsorption bed  311  or the second adsorption bed  321  but decreases the temperature of the cooling liquid passing the first evaporator/condenser  312  or the second evaporator/condenser  322 , and in consequence cooling is effectuated. 
         [0028]    The first set of valve  40  comprises at least a switch valve  41  and a plurality of pipelines  42 . The switch valve  41  and the pipelines  42  together enable the fuel cell apparatus  10 , the cooling tank  20 , the first adsorption bed  311 , and the second adsorption bed  321  to be connected to one another. The switch valve  41  is a two-way valve, a three-way valve, a four-way valve, or a combination thereof, but is not limited thereto. 
         [0029]    The second set of valve  50  comprises at least a switch valve  51  and a plurality of pipelines  52 . The switch valves  51  and the pipelines  52  together enable the cooling tank  20 , the first evaporator/condenser  312 , and the second evaporator/condenser  322  to be connected to one another. The switch valve  51  is a two-way valve, a three-way valve, a four-way valve, or a combination thereof, but is not limited thereto. 
         [0030]    As shown in  FIGS. 1 through 4 , in order to facilitate switching of the first set of valve  40  and of the second set of valve  50 , the heat recycling system  100 ,  100 ′ of fuel cells further comprises an automatic control system  70  that communicates between the fuel cell apparatus  10 , the cooling tank  20 , and the adsorption refrigerating apparatus  30  for monitoring respective states of the fuel cell apparatus  10 , the cooling tank  20 , and the adsorption refrigerating apparatus  30 , so as to control switching on/off of the first set of valve  40  and of the second set of valve  50 . 
         [0031]    As shown in  FIG. 1 , when both the first set of valve  40  and the second set of valve  50  are at a first state, the switch valves  41 ,  51  are at the first state, allowing the fuel cell apparatus  10  to communicate with the first adsorption bed  311  in the first chamber  31 , the cooling tank  20  to communicate with the second adsorption bed  321  in the second chamber  32 , and the cooling tank  20  to also communicate with the first evaporator/condenser  312  and the second evaporator/condenser  322 . 
         [0032]    Thus, the cooling liquid in the cooling tank  20  is guided through the fuel cell apparatus  10  by the pipelines  42  of the first set of valve  40 , so that waste heat generated by the fuel cell apparatus  10  is removed therefrom by the cooling liquid and recycled for use as a heat source of the adsorption refrigerating apparatus  30 . 
         [0033]    The high-temperature cooling liquid from the fuel cell apparatus  10  passes the switch valve  41  at the first state and enters the first adsorption bed  311  in the first chamber  31 , so as to enable desorption to take place in the first adsorption bed  311 . Owing to desorption, the temperature of the cooling liquid introduced into the first adsorption bed  311  decreases. The low-temperature cooling liquid from the first adsorption bed  311  is guided back to the cooling tank  20  via the pipelines  42 . 
         [0034]    Meanwhile, the first evaporator/condenser  312  functions as the condenser. The cooling liquid in the cooling tank  20  passes one of the switch valves  51  and the pipelines  52  of the second set of valve  50  and enters the first evaporator/condenser  312  in the first chamber  31 . As a result, the coolant desorbed from the first adsorption bed  311  is condensed (into liquid phase from gaseous phase) by the cooling liquid, and the temperature of the cooling liquid discharged from the first evaporator/condenser  312  increases. The cooling liquid discharged from the first evaporator/condenser  312  is guided back to the cooling tank  20  by another one of the switch valves  51  and the pipelines  52  of the second set of valve  50 . 
         [0035]    When both the first set of valve  40  and the second set of valve  50  are at the first state, the switch valve  41  and the pipelines  42  of the first set of valve  40  also guide the cooling liquid from the cooling tank  20  to the second chamber  32  of the adsorption refrigerating apparatus  30  so as to enable adsorption to take place in the second adsorption bed  321  in the second chamber  32  and thereby increase the temperature of the cooling liquid introduced into the second adsorption bed  321 . The high-temperature cooling liquid discharged from the second adsorption bed  321  is guided back to the cooling tank  20  via the pipelines  42 . 
         [0036]    Meanwhile, the second evaporator/condenser  322  functions as the evaporator. The cooling liquid in the cooling tank  20  is guided into the second evaporator/condenser  322  in the second chamber  32  by one of the switch valves  51  and the pipelines  52  of the second set of valve  50 . The second evaporator/condenser  322  absorbs heat to evaporate the coolant (i.e., into gaseous phase from liquid phase), thereby decreasing the temperature of the cooling liquid passing the second evaporator/condenser  322 . The cooling liquid discharged from the second evaporator/condenser  322  returns to the cooling tank  20  via another one of the switch valves  51  and the pipelines  52  of the second set of valve  50 . 
         [0037]    Referring to  FIG. 2 , upon completion of desorption in the first adsorption bed  311 , the switch valve  41  of the first set of valve  40  is switched to a second state, so as to change the direction of flow of the cooling liquid and put the fuel cell apparatus  10  in communication with the second adsorption bed  321  in the second chamber  32 , and the cooling tank  20  in communication with the first adsorption bed  311  in the first chamber  31 . 
         [0038]    Thus, the high-temperature cooling liquid from the fuel cell apparatus  10  enters the second adsorption bed  321  in the second chamber  32  to enable desorption to take place in the second adsorption bed  321 . Meanwhile, the cooling liquid in the cooling tank  20  is guided to the first adsorption bed  311  in the first chamber  31  to enable adsorption to take place in the first adsorption bed  311 . Hence, the first set of valve  40  is switched between different states to allow desorption and adsorption to alternate between the first adsorption bed  311  and the second adsorption bed  321 , thereby maintaining the operating temperature of the fuel cell apparatus  10  within an appropriate range. 
         [0039]    As shown in  FIGS. 3 and 4 , the heat recycling system  100 ′ of fuel cells further comprises an air conditioning apparatus  60  connected to the cooling tank  20 , the first evaporator/condenser  312 , and the second evaporator/condenser  322  by means of the second set of valve  50 . 
         [0040]    With the first evaporator/condenser  312  or the second evaporator/condenser  322  functioning as the evaporator, heat energy of the cooling liquid passing the first evaporator/condenser  312  or the second evaporator/condenser  322  is absorbed to enable the first adsorption bed  311  or the second adsorption bed  321  to desorb the coolant. Meanwhile, the temperature of the cooling liquid in the first evaporator/condenser  312  or the second evaporator/condenser  322  decreases to produce a cooling effect. Therefore, the low-temperature cooling liquid produced by the first evaporator/condenser  312  or the second evaporator/condenser  322  can be applied to the air conditioning apparatus  60 . 
         [0041]    Referring to  FIG. 3 , when the first set of valve  40  is at the first state, with the second evaporator/condenser  322  functioning as the evaporator, the switch valves  51  and the pipelines  52  of the second set of valve  50  together allow the air conditioning apparatus  60  to communicate with the second evaporator/condenser  322  in the second chamber  32 . Accordingly, the low-temperature cooling liquid from the second evaporator/condenser  322  is guided into the air conditioning apparatus  60  and enables the air conditioning apparatus  60  to produce cool air. The cooling liquid is thus heated up and guided back to the cooling tank  20  through the switch valves  51  and the pipelines  52 . 
         [0042]    Referring to  FIG. 4 , when the second set of valve  50  is at the second state, with the switch valves  51  of the second set of valve  50  switched to the second state and the first evaporator/condenser  312  functioning as the evaporator, the air conditioning apparatus  60  is allowed to communicate with the first evaporator/condenser  312  in the first chamber  31 . Thus, the low-temperature cooling liquid from the first evaporator/condenser  312  is guided into the air conditioning apparatus  60  and enables the air conditioning apparatus  60  to produce cooling air. The cooling liquid is thus heated up and guided back into the cooling tank  20  through the switch valves  51  and the pipelines  52 . 
         [0043]    The switch valves  51  of the second set of valve  50  is timely switched between different states according to the state of the first set of valve  40 , so as to continually introduce the low-temperature cooling liquid from the first evaporator/condenser  312  or the second evaporator/condenser  322  into a low-temperature liquid circuit of the air conditioning apparatus  60 . As a result, the air conditioning apparatus  60  continually uses the low-temperature cooling liquid provided by the adsorption refrigerating apparatus  30  to turn incoming hot air into cool air and delivers the cool air. 
         [0044]    In conclusion, in the above-mentioned present preferred embodiments, the adsorption refrigerating apparatus  30  reduces the temperature of the cooling liquid discharged from the fuel cell apparatus  10  and guides the cooling liquid back to the cooling tank  20  so as to recycle the cooling liquid continually and thus maintain the operating temperature of the fuel cell apparatus  10  within an appropriate range. In addition, waste heat generated by the fuel cell apparatus  10  is recycled for use as a heat source of the adsorption refrigerating apparatus  30 . Hence, the fuel cell apparatus  10  not only generates electric power but also works in conjunction with the adsorption refrigerating apparatus  30  and the air conditioning apparatus  60  to produce cool air, so that power generation and cool air production are effectuated concurrently. 
         [0045]    The foregoing specific embodiments are only intended to describe the characteristics of the present invention and enable persons skilled in the art to gain insight into the disclosure of the present invention so as to implement the present invention. It is understood that the embodiments are not intended to restrict the scope of the present invention. Hence, all equivalent modifications and variations made in the foregoing embodiments without departing from the spirit and principle of the present invention as disclosed herein should fall within the scope of the appended claims.