[TRNSYS-users] Heat exchangers

[David Bradley]

Joke,

> a) heat recovery with glycol battery (only sensible) ?
>
I'm afraid that I am not familiar with that technology
>
> b) heat recovery with plate heat exchanger (only sensible) ?
>
I would recommend Type760. You can use Type91 for this but since Type91 
doesn't do any psychrometric calculations, you have to pass the air 
temperature through the heat exchanger model and to a Type33. You also 
have to pass the absolute humidity ratio around the the heat exchanger 
and into the Type33. With the outlet temperature and the inlet humidity 
ratio (which doesn't change across the HX in a sensible-only device, you 
can get the outlet RH.
>
> c) heat recovery with rotational heat exchanger (sensible + latent) ?
>
Type667. The easiest way to use this is to get some design points for 
inlet and outlet conditions and then tune the latent and sensible 
effectiveness inputs until you can match the design points.
>
> Is it correct that in trnsys 16 there is only a type for a plate heat 
> exchanger (type 91)?
>
Type91 models a constant effectiveness heat exchanger. There is also 
Type5, which models a number of different heat exchanger configurations 
(shell and tube, counter flow, cross flow, etc.) but asks you to provide 
the UA value for the heat exchanger. You can look in the Type5 
documentation at the form of the UA equations; one of them might match a 
plate heat exchanger well enough.
>
> But in the Tess library you do have the different types? What's the 
> difference between type 667a en 667c?
>
There is no difference between 667a and 667c. The same modeling 
methodology can be used to model a number of different technologies. An 
excerpt from the documentation:

"Type667 uses a "constant effectiveness -- minimum capacitance" approach 
to model an air to air heat
recovery device in which two air streams are passed near each other so 
that both energy and possibly
moisture may be transferred between the streams. Because of the 
"constant effectiveness -- minimum
capacitance" methodology, the model may be used to model a device with 
any configuration of air
streams (parallel flow, cross flow, counter flow, etc.) and may be used 
to model the sensible and latent
aspects of an air to air heat exchanger, an enthalpy wheel, a 
hygroscopic heat exchanger or a permeable
walled flat plate recuperator, among other devices."

Best,
  David

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