[TRNSYS-users] On using Type 653 radiant floor correctly

[Javier Vega via TRNSYS-users]

Hello Jeff,

I also took a look into the code too. Exactly the HX calculation didn't
make sense to me, specially the UA calculations in the "Calculate the UA
value for the "heat exchanger" per circuit". I wasn't sure if they had a
problem or it was me that I wasn't catching something.

Thanks a lot for your help again, and at the same time I'm glad I helped
the model in some way.

Kind regards,
Javier

2017-05-09 13:52 GMT-03:00 Jeff Thornton <thornton at tess-inc.com>:

> Javier,
>
> I took a look at the code for Type 653 and found a small problem with the
> circuit definitions.  The pipe length entered as a parameter should be per
> circuit and I have added this clarification in the profroma.  But I also
> found and fixed a problem with the HX calculation with multiple circuits.
> In the short term, just use 1-circuit in your model and put in the total
> pipe length for all of the circuits.  To get more energy into and out of
> the slab, you'll simply have to increase the inlet flow rate as the heat
> transfer is a simple effectiveness solution.
>
>
>
> Jeff
>
> ---
> Jeff Thornton
> President - TESS LLC
> 22 N. Carroll Street, Madison WI USA 53703
> Office: (608) 274-2577  Fax: (608) 278-1475www.tess-inc.com
> E-Mail: thornton at tess-inc.com
>
> On 05/09/2017 10:59 am, Javier Vega via TRNSYS-users wrote:
>
> Hello TRNSYS users,
>
> I'm using a Type 653 radiant floor to transfer energy to a TRNSYS Type 56
> building. I'm using the model in "Mode 1", which means the module is not
> coupled to Type 56 but it computes all outputs through an energy balance.
> Then, I transfer the energy to the thermal zone as a Gain Input.
>
> My first design, lead me to set 1600 (kg/h) of water flow on Type 653.
> Nonetheless, the system behaviour made me rise the flow to somewhat 2500
> (kg/h) to meet thermal confort.
>
> This would lead to water speeds to high in the circuit, so it's unrealistic*.
> So I want to set the design to maybe 3 parallel circuits.*
>
> *The thing is, I don't understand well how the module should be used then.
> If I set 3 identical parallel circuits in Parameter 19, should I set in
> Parameter 16 "Total pipe lenght" the sum of the 3 circuits or the length of
> each one*?
>
> *Either way, in both scenarios I obtain less energy gains than with a sole
> circuit*. I don't really understand why this happens if the heat transfer
> is considered with an effectiveness approach. It is supposedly the same
> total inlet flow with the same temperature and the same effectiveness
> assumption.
>
> Kind regards,
> Javier Vega
>
>
>
>
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