Abstract:
The present invention discloses an adsorption type refrigerator that automatically determines the switchover point. The adsorption type refrigerator includes a first vacuum chamber, a second vacuum chamber, a third vacuum chamber and a waterway structure. The waterway structure is connected to a first adsorption bed in the first vacuum chamber and a second adsorption bed in the second vacuum chamber. The waterway structure simultaneously conveys hot water into the first adsorption bed and cold water into the second adsorption bed, or simultaneously conveys cold water into the first adsorption bed and hot water into the second adsorption bed so as to allow the first and the second adsorption beds to conduct adsorption and desorption alternatively. This alternation creates pressure variation in the three vacuum chambers, which is then utilized to automatically determine the switchover point at which the refrigerator can provide and maintain a cold, stable environment.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Technical Field 
         [0002]    The present invention relates to adsorption type refrigerators, and more particularly, to an adsorption type refrigerator that automatically determines the switchover point so as to provide and maintain a cold, stable environment. 
         [0003]    2. Description of Related Art 
         [0004]    An adsorption type refrigerator is composed of adsorption beds, condensers, and evaporators. The adsorption type refrigerator works by importing cold water to cool down the adsorption beds so that porous matter (e.g. silica gel, zeolite or active carbon) in the adsorption beds adsorbs a refrigerant, which is typically a gaseous heat-transferring medium (e.g. water, methanol, ethanol or ammonia). When the heat-transferring medium evaporates and adsorbs a huge amount of latent heat of evaporation from the ambient environment, the adsorption type refrigerator effects refrigeration. 
         [0005]    When saturated and no more capable of adsorption, the adsorption beds must be heated for desorption, and at the same time the evaporated refrigerant is condensed for reuse. Solar energy or industrial waste energy may be used as the heat resource for desorption of the adsorption beds and hence the heat source for refrigeration, thereby answering to the worldwide trend of environmental protection and energy preservation. 
         [0006]    Conventionally, in order to effect continuous refrigeration, an adsorption type refrigerator has at least two adsorption beds that conduct adsorption and desorption alternatively. However, when any of the adsorption beds performs adsorption or desorption at the limit of its adsorption or desorption capacity, the adsorption type refrigerator is actually incapable of refrigeration, even though there is still circulation between cold water and hot water. As a result, not only is the overall refrigeration efficiency of the adsorption type refrigerator lowered, but also the excessively introduced cold water may over cool the adsorption beds and freeze the refrigerant, which in turn shortens the service life of the adsorption type refrigerator. 
         [0007]    Additionally, even if the two adsorption beds have similar configures and materials, their performances of adsorption or desorption are usually different. Because of that, the optimal refrigeration efficiency of the adsorption type refrigerator cannot be ensured even by setting parameters that lead to automatic switchover between the adsorption beds. Hence, a major challenge facing adsorption type refrigerators is to effectively and accurately determine the switchover point of adsorption and desorption between the two adsorption beds. 
       SUMMARY OF THE INVENTION 
       [0008]    The present invention provides an adsorption type refrigerator that automatically determines the switchover point, wherein by detecting pressure gradients inside each vacuum chamber, a valve switchover point can be determined so as to not only identify the preferred switchover point of the adsorption type refrigerator, but also improve the refrigeration stability of the adsorption type refrigerator. 
         [0009]    To achieve the above effects, the present invention provides an adsorption type refrigerator that automatically determines the switchover point. The adsorption type refrigerator comprises: a first vacuum chamber having a first adsorption bed, a first condenser, a first evaporator, and a first vacuum gauge, wherein the first adsorption bed has a first inlet and a first outlet, and the first vacuum gauge serves to measure a first vacuum pressure inside the first vacuum chamber; a second vacuum chamber abreast with the first vacuum chamber and having a second adsorption bed, a second condenser, a second evaporator, and a second vacuum gauge, wherein the second adsorption bed has a second inlet and a second outlet, and the second vacuum gauge serves to measure a second vacuum pressure inside the second vacuum chamber; a third vacuum chamber having a top connected to bottoms of the first vacuum chamber and the second vacuum chamber and including a third evaporator and a third vacuum gauge, wherein the third evaporator has an ice water inlet and an ice water outlet, and the third vacuum gauge serves to measure a third vacuum pressure inside the third vacuum chamber; and a waterway structure comprising a plurality of pipes and a plurality of valves, wherein the pipes are mutually connected through the valves, and the valves are switchable between a first position for simultaneously conveying hot water into the first adsorption bed and cold water into the second adsorption bed and a second position for simultaneously conveying the cold water into the first adsorption bed and the hot water into the second adsorption bed. When the first vacuum pressure reaches a minimum, the valves are switched to the first position, and when the second vacuum pressure reaches the minimum, the valves are switched to the second position. 
         [0010]    Implementation of the present invention at least achieves the following advantageous effects: 
         [0011]    1. The preferred switchover point for the adsorption beds can be accurately and automatically identified by detecting the vacuum pressures inside the vacuum chambers. 
         [0012]    2. By effectively identifying the preferred switchover point for the adsorption beds, the refrigeration efficiency of the adsorption type refrigerator can be improved. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    The invention as well as a preferred mode of use, further objectives and advantages thereof will be best understood by reference to the following detailed description of illustrative embodiments when read in conjunction with the accompanying drawings, wherein: 
           [0014]      FIG. 1  and  FIG. 2  are schematic drawings showing the operation of an adsorption type refrigerator that automatically determines the switchover point according to a first aspect of the present invention; and 
           [0015]      FIG. 3  through  FIG. 6  are schematic drawings showing the operation of an adsorption type refrigerator that automatically determines the switchover point according to a second aspect of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0016]      FIG. 1  and  FIG. 2  show the operation of an adsorption type refrigerator  100  that automatically determines the switchover point according to a first aspect of the present invention while  FIG. 3  through  FIG. 6  show the operation of an adsorption type refrigerator  100  that automatically determines the switchover point according to a second aspect of the present invention. 
         [0017]    As shown in  FIG. 1 , the present embodiment is an adsorption type refrigerator  100  that automatically determines the switchover point. The adsorption type refrigerator  100  comprises: a first vacuum chamber  10 , a second vacuum chamber  20 , a third vacuum chamber  30 , and a waterway structure  40 . 
         [0018]    The first vacuum chamber  10  includes: a first adsorption bed  11 , a first condenser  12 , a first evaporator  13 , and a first vacuum gauge  14 . The first adsorption bed  11  has a first inlet  11   a  and a first outlet  11   b . The first vacuum gauge  14  serves to measure a pressure inside the first vacuum chamber  10  and identify the pressure as a first vacuum pressure. 
         [0019]    The second vacuum chamber  20  is set abreast with the first vacuum chamber  10 . The second vacuum chamber  20  includes: a second adsorption bed  21 , a second condenser  22 , a second evaporator  23 , and a second vacuum gauge  24 . The second adsorption bed  21  has a second inlet  21   a  and a second outlet  21   b . The second vacuum gauge  24  serves to measure a pressure inside the second vacuum chamber  20  and identify the pressure as a second vacuum pressure. 
         [0020]    The first condenser  12  and the second condenser  22  correspond in position to the first adsorption bed  11  and the second adsorption bed  21 , respectively. The first condenser  12  and the second condenser  22  share a conjoint condenser tube  60  that is configured through both the first vacuum chamber  10  and the second vacuum chamber  20 . The condenser tube  60  allows cold water to flow therethrough from the first condenser  12  to the second condenser  22 , where the cold water is discharged. 
         [0021]    Each of the first evaporator  13  and the second evaporator  23  has: at least one evaporator tray  131  or  231  and a heat-transferring pipe  132  or  232 . The evaporator trays  131  and  231  serve to carry a heat-transferring medium. The heat-transferring pipes  132  and  232  are coiled on the evaporator trays  131  and  231 , respectively. Each of the heat-transferring pipes  132  and  232  has its two ends (not shown) communicating with a third vacuum chamber  30 , so that a gasified heat-transferring medium inside the third vacuum chamber  30  can flow into the heat-transferring pipes  132  and  232  to transfer heat to the heat-transferring medium in the evaporator trays  131  and  231 , respectively. In the present embodiment, the heat-transferring medium is water. 
         [0022]    The third vacuum chamber  30  has its top connected to bottoms of the first vacuum chamber  10  and the second vacuum chamber  20 . The third vacuum chamber  30  has therein a third evaporator  31  and a third vacuum gauge  32 . The third evaporator  31  includes an ice water inlet IWI and an ice water outlet IWO. Ice water is introduced through the ice water inlet IWI to evaporate and gasify the heat-transferring medium; consequently the ice water is cooled. Afterward, the cooler ice water is led out through the ice water outlet IWO. The third vacuum gauge  32  serves to measure a pressure inside the third vacuum chamber  30  and identify the pressure as a third vacuum pressure. 
         [0023]    The third evaporator  31  comprises at least one evaporation heat-exchanging tray  311  and a heat-exchanging pipe  312 . The evaporation heat-exchanging tray  311  also carries a heat-transferring medium, while the heat-exchanging pipe  312  has its two ends connected to the ice water inlet IWI and the ice water outlet IWO, respectively. The heat-exchanging pipe  312  is coiled on each evaporation heat-exchanging tray  311 . 
         [0024]    While the ice water enters the heat-exchanging pipe  312  through the ice water inlet IWI and gasifies the heat-transferring medium in the evaporation heat-exchanging tray  311 , the ice water gasifies the heat-transferring medium and is thus cooled. The gaseous heat-transferring medium rises and enters the heat-transferring pipes  132 ,  232  to conduct heat exchange with the heat-transferring medium in the evaporator trays  131 ,  231 . Then, the heat-transferring medium in the heat-transferring pipes  132 ,  232  is condensed into liquid and drops back to the evaporation heat-exchanging tray  311 . 
         [0025]    The waterway structure  40  comprises a plurality of pipes  41  and a plurality of valves  42 . The pipes  41  are in mutual communication through the valves  42 . The valves  42  have a first position and a second position. When the valves  42  are in the first position, hot water is conveyed into the first adsorption bed  11 , and cold water is conveyed into the second adsorption bed  21  simultaneously. When the valves  42  are in the second position, the cold water is conveyed into the first adsorption bed  11 , and hot water is conveyed into the second adsorption bed  21  simultaneously. 
         [0026]    With different designs of the pipes  41  and the valves  42 , the present embodiment performs different refrigeration operations so as for the adsorption type refrigerator  100  to provide stable refrigeration. 
         [0027]    As shown in  FIG. 1  and  FIG. 2 , in a first aspect of the present embodiment, the valves  42  in the waterway structure  40  of the adsorption type refrigerator  100  include a first valve  42   a , a second valve  42   b , a third valve  42   c , and a fourth valve  42   d.    
         [0028]    The first valve  42   a  guides hot water from the hot water inlet HWI into the first inlet  11   a  or the second inlet  21   a , thus causing the corresponding adsorption bed  11  or  21  to conduct desorption. The second valve  42   b  brings the first outlet  11   b  or the second outlet  21   b  into communication with the hot water outlet HWO, so as to guide the hot water outward. The third valve  42   c  allows cold water to flow from the cold water inlet CWI into the first inlet  11   a  or the second inlet  21   a , thus causing the corresponding adsorption bed  11  or  21  to conduct adsorption. Then, the fourth valve  42   d  brings the first outlet  11   b  or the second outlet  21   b  into communication with the cold water outlet CWO and thereby guides the cold water outward. 
         [0029]    Referring to  FIG. 1 , the valve  42  is at the first position. The first valve  42   a  guides hot water from the hot water inlet HWI to the first inlet  11   a , so the first adsorption bed  11  conducts desorption. The second valve  42   b  then guides the hot water from the first outlet  11   b  to the hot water outlet HWO, so the first vacuum pressure inside the first vacuum chamber  10  rises gradually. At the same time, the third valve  42   c  guides cold water from the cold water inlet CWI to the second inlet  21   a  and thus makes the second adsorption bed  21  conduct adsorption. At last, the fourth valve  42   d  guides the cold water from the second adsorption bed  21  to the cold water outlet CWO. As cold water is continuously introduced into the second adsorption bed  21  to cause adsorption of the second adsorption bed  21 , the second vacuum pressure inside the second vacuum chamber  20  decreases over time. 
         [0030]    When the second vacuum pressure reaches a minimum, which means the second adsorption bed  21  has reached adsorption saturation and is not capable of adsorption anymore, the valves  42  are switched to the second position. At this time, the second vacuum pressure is lower than the third vacuum pressure, and the third vacuum pressure is lower than the first vacuum pressure. 
         [0031]    As show in  FIG. 2 , the valve  42  is at the second position. The third valve  42   c  guides cold water from the cold water inlet CWI to the first inlet  11   a , so the first adsorption bed  11  conducts adsorption. Then, the fourth valve  42   d  guides the cold water coming from the first adsorption bed  11  to flow out through the cold water outlet CWO, so the first vacuum pressure inside the first vacuum chamber  10  gradually decreases. The first valve  42   a  guides hot water to the second adsorption bed  21 , so as to make the second adsorption bed  21  conduct desorption. Afterward, the second valve  42   b  guides the hot water coming from the second adsorption bed  21  to flow out through the hot water outlet HWO, so the second vacuum pressure inside the second vacuum chamber  20  also rises over time. 
         [0032]    When the first vacuum pressure reaches a minimum, which means the first adsorption bed  11  is saturated and incapable of adsorption and hence the first vacuum pressure cannot decrease anymore, the valves  42  are switched back to the first position. At this time, the first vacuum pressure is lower than the third vacuum pressure, and the third vacuum pressure is lower than the second vacuum pressure. The adsorption type refrigerator  100  continuously operates in this manner to provide continuous refrigeration. 
         [0033]    Referring to  FIG. 3  through  FIG. 6 , in a second aspect of the present embodiment, the valves  42  in the waterway structure  40  of the adsorption type refrigerator  100  include a fifth valve  42   e , a sixth valve  42   f , a seventh valve  42   g , an eighth valve  42   h , a ninth valve  42   i , and a tenth valve  42   j.    
         [0034]    Compared with the first aspect, the second aspect has two additional valves, which allow the adsorption type refrigerator  100  to conduct heat recovery. The heat recovery is conducted before the adsorption bed  11  or  12  conducts adsorption, so as to cool the adsorption bed  11  or  12  in advance and thereby improve the refrigeration efficiency of the adsorption type refrigerator  100 . 
         [0035]    The fifth valve  42   e  is connected to the hot water inlet HWI for guiding hot water to the sixth valve  42   f  or the seventh valve  42   g . The sixth valve  42   f  is connected to the fifth valve  42   e  as well as the hot water outlet HWO. The sixth valve  42   f  serves to guide the hot water introduced through the fifth valve  42   e  or the eighth valve  42   h  to the hot water outlet HWO for discharge. 
         [0036]    The seventh valve  42   g  is connected to the fifth valve  42   e  and is also connected to the first inlet  11   a  and the second inlet  21   a . By controlling the seventh valve  42   g , hot water coming from the hot water inlet HWI is guided to the first adsorption bed  11  or the second adsorption bed  21 . Or, by controlling the seventh valve  42   g , cold water coming from the eighth valve  42   h  is guided to the first inlet  11   a  or the second inlet  21   a . The eighth valve  42   h  is connected to the sixth valve  42   f  and is also connected to the first outlet  11   b  and the second outlet  21   b . The eighth valve  42   h  is further connected to the seventh valve  42   g  by means of a bypass pipe  41   a.    
         [0037]    The bypass pipe  41   a  serves to connect the pipe between the eighth valve  42   h  and the sixth valve  42   f  with the pipe between the fifth valve  42   e  and the seventh valve  42   g . In addition, the bypass pipe  41   a  is a one-way pipe, so water in the bypass pipe  41   a  can only flow from the eighth valve  42   h  toward the seventh valve  42   g.    
         [0038]    The ninth valve  42   i  is connected to the seventh valve  42   g  and also to the first inlet  11   a  and the second inlet  21   a . By controlling the ninth valve  42   i , cold water coming from the cold water inlet CWI is guided to the first adsorption bed  11  or the second adsorption bed  21 . The tenth valve  42   j  is connected to the cold water outlet CWO and is also connected to the first outlet  11   b  and the second outlet  21   b  so as to guide the cold water to the cold water outlet CWO. 
         [0039]    Referring to  FIG. 3 , the valves  42  are in the first position. By controlling the fifth valve  42   e  and the seventh valve  42   g  to guide hot water into the first adsorption bed  11 , and controlling the eighth valve  42   h  and the sixth valve  42   f  to guide the hot water in the first adsorption bed  11  to the hot water outlet HWO, the first adsorption bed  11  conducts desorption and thereby increases the first vacuum pressure in the first vacuum chamber  10 . At the same time, cold water is introduced into the second adsorption bed  21  through the ninth valve  42   i  and guided to the cold water outlet CWO through the tenth valve  42   j , so the second adsorption bed  21  conducts adsorption, causing the second vacuum pressure inside the second vacuum chamber  20  to decrease gradually. 
         [0040]    When the second vacuum pressure reaches a minimum, meaning that the second adsorption bed  21  has reached adsorption saturation and is no longer capable of adsorption, the valves  42  are switched to the second position. At this time, the second vacuum pressure is lower than the third vacuum pressure, and the third vacuum pressure is lower than the first vacuum pressure. Additionally, the present aspect may conduct heat recovery. A first heat recovery may be conducted before the valves are switched to the second position, so as to cool the first adsorption bed  11  in advance. 
         [0041]    As shown in  FIG. 4 , the valves  42  are now in a state for the first heat recovery, where hot water is directly introduced through the hot water inlet HWI and instantly drained at the hot water outlet HWO by way of the fifth valve  42   e  and the sixth valve  42   f ; consequently, the hot water does not flow through any of the adsorption beds  11 ,  21 . Cold water coming from the cold water inlet CWI runs through the ninth valve  42   i  to the first adsorption bed  11  and, after passing through the eighth valve  42   h , the bypass pipe  41   a  and the seventh valve  42   g , enters the second adsorption bed  21 . Finally, the cold water passes through the tenth valve  42   j  and is drained at the cold water outlet CWO. 
         [0042]    Referring to  FIG. 5 , the valves  42  are now at the second position. Hot water flows through the fifth valve  42   e  and the seventh valve  42   g  and enters the second adsorption bed  21  by way of the second inlet  21   a . The hot water coming from the second adsorption bed  21  is guided to the hot water outlet HWO via the eighth valve  42   h  and the sixth valve  42   f , so as to make the second adsorption bed  21  conduct desorption, thereby causing the second vacuum pressure inside the second vacuum chamber  20  to rise gradually. Meanwhile, cold water is introduced into the first adsorption bed  11  through the ninth valve  42   i  and is drained at the cold water outlet CWO via the tenth valve  42   j , so the first adsorption bed  11  conducts adsorption and adsorbs the heat-transferring medium in the evaporator tray  131 , causing the pressure inside the first vacuum chamber  10  to decrease gradually. 
         [0043]    When the first vacuum pressure reaches a minimum, meaning that the first adsorption bed  11  is saturated and capable of no more adsorption and that the first vacuum pressure cannot decrease anymore, the valves  42  are switched back to the first position. At this time, the first vacuum pressure is lower than the third vacuum pressure, and the third vacuum pressure is lower than the second vacuum pressure. In addition, the present aspect may conduct a second heat recovery. The second heat recovery is conducted before the valves  42  are switched back to the first position, with a view to cooling the second adsorption bed  21  in advance. 
         [0044]    A shown in  FIG. 6 , the valves  42  are in a state for the second heat recovery, where hot water is directly guided to the hot water outlet HWO via the fifth valve  42   e  and the sixth valve  42   f  without entering the first and second adsorption beds  11 ,  21 . At the same time, cold water flows into the second adsorption bed  21  through the ninth valve  42   i  and then passes through the eighth valve  42   h , the bypass pipe  41   a , and the seventh valve  42   g , before entering the first adsorption bed  11 . At last, the cold water is drained at the cold water outlet CWO by way of the tenth valve  42   j.    
         [0045]    More particularly, in the present aspect, a mass recovery valve  70  is provided between the first vacuum chamber  10  and the second vacuum chamber  20 . The mass recovery valve  70  serves to communicate the first vacuum chamber  10  with the second vacuum chamber  20  for mass recovery. 
         [0046]    When the first, second, and third vacuum pressures are to trigger the switching between the positions, the mass recovery valve  70  may be opened to communicate the first vacuum chamber  10  with the second vacuum chamber  20  so that the pressures in the two vacuum chambers  10 ,  20  are balanced rapidly. Therefore, the one conducting desorption can proceed with desorption, and the one conducting adsorption can further conduct adsorption, allowing the adsorption type refrigerator  100  to provide stable refrigeration at improved refrigeration efficiency. 
         [0047]    Thus, when the vacuum pressure corresponding to the adsorption bed  11  or  21  that conducts adsorption reaches the minimum, it indicates that the adsorption bed  11  or  21  has completed adsorption and is incapable of adsorbing any heat-transferring medium and that the vacuum pressure cannot decrease anymore. Hence, the switchover point of the adsorption type refrigerator  100  can be determined by monitoring the vacuum pressures. 
         [0048]    In addition, the adsorption type refrigerator  100  further comprises three adjusting pipes  50  that communicate with the first vacuum chamber  10 , the second vacuum chamber  20 , and the third vacuum chamber  30 , respectively, for independently adding water into or vacuuming the first vacuum chamber  10 , the second vacuum chamber  20 , and the third vacuum chamber  30 , respectively. Particularly, vacuuming and water supply are conducted successively prior to start-up of the adsorption type refrigerator  100 . 
         [0049]    The adsorption type refrigerator  100  also includes three drainage pipes  51  that communicate with the evaporator trays  131 ,  231  and the evaporation heat-exchanging tray  311 , respectively, for draining the water carried by the trays  131 ,  231 ,  311  (i.e. the heat-transferring medium). 
         [0050]    The present invention has been described with reference to the preferred embodiments, and it is understood that the embodiments are not intended to limit the scope of the present invention. Moreover, as the contents disclosed herein should be readily understood and can be implemented by a person skilled in the art, all equivalent changes or modifications which do not depart from the concept of the present invention should be encompassed by the appended claims.