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[EnergyPlus_Support] Re: Low Temperature Radiant Cooling Won't Meet Loads

So my source water is coming in at 58F, but when I report the temperature at the source layer, its most in the neighborhood of 65. Is that normal to have that kind of delta T from inlet water to source  layer temp?

Further, on the outside layer of the radiant panel the temperature is about the same, 65 degrees. Is this a realistic temperature for a radiant panel in full cooling mode?

Also, I'm not getting the 75w/m2 cooling rate. The hydronic cooling energy in is around 23 w/m2. The surface convection heat gain is around -9.7 w/m2. Should the hydronic cooling energy and the convective heat gain from the surface in question be the same?


--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "Jean marais" <jeannieboef@...> wrote:
>
> Monitor the surface temp of your radiant system. monitor the mass flow rates. I would hard size the pipes and mass flow rates realistically (the autosizing at the, for radiant system, conditions may be wrong). Hard size. The setpoint in the lowtemprad object should be lower than that of the zone SP by about 2 degC.
> 
> For chilled ceiling you'll get realistically a max of 75 W/m2, and for a floor 20-40 W/m2 at Roomtemp 26degC and surface temps 16 degC. These systems are limited by fundimentals of heat transfer via radiation and convection. Even blowing air across to increase the convection transfer has minimal effect. 
> 
> Do some hand calcs. Let us know how you get on.
>




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