BACKGROUND 
     1. Technical Field 
     The present disclosure relates to computer systems, and more particularly to a computer system with a waste heat recycling device. 
     2. Description of Related Art 
     Computer systems have attained widespread use in many segments of today&#39;s modern society. Computer systems are typically provided with enclosures, which protect the operating components therein. Many components of computers generate heat during operation, making it necessary to cool those components so that proper operation continues. Because of the confined space of the enclosure, natural heat dissipation is difficult. Cooling strategies for computers usually rely upon forced airflow through the computer enclosure. It can be a waste to exhaust the heat which can be reused directed to the air from the computer system, for example, the heat air can be guided to warm hand or warm cold room. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Many aspects of the embodiments can be better understood with references to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the embodiments. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
         FIG. 1  is an exploded, isometric view of an embodiment of a computer system. 
         FIG. 2  is an exploded view of a retaining mechanism and a partial view of air-duct of  FIG. 1 . 
         FIG. 3  is an embodiment of a retaining mechanism. 
         FIG. 4  is an assembled view of the computer system of  FIG. 1 . 
         FIG. 5  is similar to  FIG. 3 , but viewed from another aspect. 
     
    
    
     DETAILED DESCRIPTION 
     The disclosure is illustrated by way of example and not by way of limitation in the figures of the accompanying drawings in which like references indicate similar elements. It should be noted that references to “an” or “one” embodiment in this disclosure are not necessarily to the same embodiment, and such references mean at least one. 
     Referring to  FIG. 1 , one embodiment of a computer system includes a computer  100 , an air-duct  30 , two retaining mechanisms  50 , and a fan  70 . The two retaining mechanisms  50  are respectively used for connecting an end of the air-duct  30  to the computer  100 , and another end of the air-duct  30  to the fan  70 . 
     The computer  100  has an enclosure. The enclosure has a heat air outlet  110  to dissipate heat from the computer  100 . In one embodiment, the air-duct  30  is a flexible pipe. 
     Referring to  FIG. 2 , the retaining mechanism  50  includes a clip  51  and a support ring  59 . The support ring  59  includes a circular main body  592  and two ridges  594  located on the main body  592 . Each ridge  594  extends along a periphery of the circular main body  592  and is located on a middle portion of the main body  592 . In one embodiment, the clip  51  can further include two clasped sub-clips  53  and  55 . The two sub-clips  53  may have same structure or corresponding structures in different embodiments. Take sub-clip  53  for example, the sub-clip  53  has a locking portion  534  and two retaining portions  537  located at two end portions of the locking portion  534 . A slot  532  is defined in a middle portion the locking portion  534  corresponding to the ridge  594 . Two locking tabs  533  are located on the locking portion  534  to connect to the computer  100  or the fan  70 . The sub-clip  55  also has a locking portion  554 , two locking tabs  553 , two retaining portions  557  and a slot  552 . Alternative structures of the sub-clips  53  and  55  may be incorporated onto the retaining portion  537 . 
     In one embodiment as shown in  FIG. 2 , each retaining portion  537  has a buckle  5372 , and a retaining hole  5572  is defined in each retaining portion  557  to engage with the buckle  5372 . 
     Referring to  FIG. 3 , in another embodiment, a clip may include two sub-clips  57  having the same structure. Each sub-clip  57  includes two retaining portions  577 , one of the two retaining portions  577  has a buckle  5772 . The two sub-clips  57  can be clasped to each other. 
     Two hanging holes  5374  and  5574  are respectively defined in the retaining portion  537  and the corresponding retaining portion  557 . The two hanging holes  5374  and  5574  are aligned with each other. 
     Referring to  FIG. 4 , when assembling the computer system, the support ring  59  is aligned with an edge of the air-duct  30 . The air-duct  30  extends and covers on the support ring  59 . The two sub-clips  53 ,  55  are respectively mounted to the support ring  59  with the slots  532  and  552  respectively engaged with the corresponding ridges  594 . The two sub-clips  53  and  55  are clasped to each other with the buckles  5372  received in the corresponding retaining holes  5572 . The edge of the air-duct  30  is sandwiched between the main body  592  and the locking portions  534  and  554  by engagement of the support ring  59  and the clip  51 . The two hanging holes  5374  and  5574  are aligned. The fan  70  is fixed to the retaining mechanism  50  on the locking tabs  533  and  553  to cover the air-duct  30 . The retaining mechanism  50  is positioned between the computer  100  and the inlet of the air-duct  30  is fixed in a similar way. 
     Referring to  FIG. 5 , the fan  70  includes a connector  75 , such as a USB port, to receive power from a USB connector of the computer  100 . The fan  70  can accelerate the removal of heat air from the computer  100 . The heated air can be recycled from the air-duct  30 . 
     It is also to be understood, however, that even though numerous characteristics and advantages have been set forth in the foregoing description of preferred embodiments, together with details of the structures and functions of the preferred embodiments, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.
A waste heat recycling device includes an air-duct, a fan and a retaining mechanism. The air-duct is connected to a heat air. The fan communicates with the air-duct. The retaining mechanism clasps the air-duct and retains the fan. The retaining mechanism includes a clip and a support ring. An edge of the air-duct is sandwiched between the clip and the support ring.