Radiant/convective

loba · Posts: 1

Hi All,

I've got some problems about the energy consumption of an underfloor heating system. I'm a student and I want to simulate the savings of energy between a radiant system and a convective one. To do that, I base the heating setpoint on operative temperature,
(>calculation options>temperature control>2 Operational temperature). Note that each of this simulations uses Gas to generate the heating energy.
I did a simulation of my building with fancoil units ("compact HVAC"), and another simulation with a radiant heating system (I must choose "simple HVAC" to model radiant heating systems, is it right?).

The Gas consumption of the radiant system was always nearly double than fancoil's one. It's strange, isn't?

After that, I opened the idf file in Energyplus. In the section "HIGH TEMP RADIANT SYSTEM", there was the field "TYPE OF HIGH TEMPERATURE RADIANT HEATER" set to "ELECTRIC". How is it possibile?

Then, I simulated the radiant system in DB againg , but at that time I chose electricity as type of fuel.
Outputs shown that consumption of electricity was exactly the same, hours by hours, of the consumption of Gas of the previous simulation.

So, I did the last test. I exported the idf of my project, and I simulated it in energyplus directly (leaving the field of type of radiant heater as "ELECTRIC") , to compare the results. In this simulation I obtained an even higher consumption of energy than the same simulation runned in DB!

Could you give me some explanations?

In the version of the program that I use (1.6.9.003) I don't find where I can set the control method of the radiant system (MAT,OPERATIVE,MRT), but I remember that in one of previous version there was. Maybe Is this the problem?

Thanks in advance for your help.

Davide Loba

PS: sorry for my english

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