[TRNSYS-users] type 17's question

[David Bradley]

Dapeng,
   The mathematics of the heat exchangers in 
Type17 are the same as the mathematics of the 
Type5 heat exchanger as far as the energy 
transferred across a given heat exchanger. 
However, Type17 assumes that there is one primary 
heat exchanger and at least two secondary heat 
exchangers so you would have to include at least 
three Type5s in your simulation to model Type17.
Kind regards,
  David


At 20:19 1/22/2008, LiDapeng wrote:


>Dear trnsys users,
>
>
>Type 17 models a cascaded waste heat recovery 
>system, e.g. only two heat exchangers in the 
>system, one is as a primary heat exchanger and 
>another is as a secondary heat exchanger. The 
>mode of two heat exchangers are all assumed to counter mode.
>
>I think the effect of type 17 is equal to two 
>type 5. So I use two type5b(counter heat 
>exchanger) instead of a type 17 and the 
>connection between two type 5b is given as: the 
>output 3 and 4 of a type 5 as the secondary heat 
>exchanger in type 17 are connected to the input 
>1 and 2 of another type 5 as the primary heat 
>exchanger in type 17; and the output 3 and 4 of 
>a type 5 as the primary heat exchanger in type 
>17 are connected to the input 1 and 2 of another 
>type 5 as the secondary heat exchanger in type 
>17. The other parameters in two type 5 are set 
>the same as the corresponded parameters in type 17.
>
>But the results from two type 5 are quitely 
>different of the one from a typ! e 17. Maybe my 
>thought is wrong, but anyone can tell me the reasons about my question?
>
>Kind regards!
>
>Dapeng
>
>
>
>
>
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