[TRNSYS-users] SDHW example TRNSYS

[Rm Chemilo via TRNSYS-users]

Thank you for your answers,

The reason I asked these question is because of the negatives values at the
outlet temperature.

<If you leave water inside a solar collector and there is no radiation
incident upon the surface and no water flow, it will quickly degrade
towards the ambient temperature.  Type1b has no mass (unlike the Tess Type
539) so it immediately decays to the ambient temperature.>

I couldn't find solar collector type 539, do you mean type538? When I check
the input parameter it has minimum and maximum array flowrate.

<It solves the same energy balance as it does when there is flow.  The
no-flow solution is found when the solar gains match the thermal losses
from the collector (absorbed energy = losses).>

Is it from Hottel-Whillier equation? can you please show me the equation?

Thanks.

On Tue, Jun 6, 2017 at 11:59 PM, Jeff Thornton via TRNSYS-users <
trnsys-users at lists.onebuilding.org> wrote:

> <Why the outlet temperature of solar collector (type 1b) same as
> temperature ambient when there is no mass flow rate and irradiance. As you
> can see in the table below, ToColl = Tambient)
>
> If you leave water inside a solar collector and there is no radiation
> incident upon the surface and no water flow, it will quickly degrade
> towards the ambient temperature.  Type1b has no mass (unlike the Tess Type
> 539) so it immediately decays to the ambient temperature.
>
> <How TRNSYS calculate the outlet temperature of the solar collector if
> there is no mass flow rate, but only the irradiance available?>
>
> It solves the same energy balance as it does when there is flow.  The
> no-flow solution is found when the solar gains match the thermal losses
> from the collector (absorbed energy = losses).
>
>
>
> 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 06/06/2017 9:09 am, Rm Chemilo via TRNSYS-users wrote:
>
> Dear all,
>
> I want to ask several questions about TRNSYS example solar domestic hot
> water (SDHW).
>
> - Why the outlet temperature of solar collector (type 1b) same as
> temperature ambient when there is no mass flow rate and irradiance. As you
> can see in the table below, ToColl = Tambient.
>
> - How TRNSYS calculate the outlet temperature of the solar collector if
> there is no mass flow rate, but only the irradiance available?
>
> Thanks.
>
> [image: Inline image 1]
>
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