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[EnergyPlus_Support] Re: EnergyPlus Model: Hydronic low temperature radiant system?
You both make valid points. Perhaps it only makes sence in certain Climates. All I know is that common practice in Germany is very different from the USA. Here almost all systems are DOAS AHU that only bring air into a zone at minimum 18-19 degC and max 60% RH. The rest of the zone loads are combated by zone equipment, either radiant or FC split units. No one here knows what a VAV ATU is. Fresh air rates are kept at a minimum...recirculation at the AHUs only happens during un occupied hours if at all.
Radiant ceilings are, as you said, often used for cooling in summer and heating in winter. In summer for cooling, the entry CW temperature will rise if the humidity climbs. We seldom use reheat at the AHU, but do sometimes overcool and then mix with warmer ODA.
I've not much experience in what is most energy efficient, but have learnt what goes for practice here.
You have given me a lot to think about.
--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, YuanLu Li <yli006@...> wrote:
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> My own interest is to minimize energy usage.
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> What you have described is what I warned the user. The incoming air must be processed to a low temperature to remove the moisture. Eplus will stop when moisture is deposited on the surface. More senser and control is required in a real system.
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> Reheat coil is one way. This panel can heat or cool. The total energy usuage in the building and the capital spending are probably more.
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> The controls available in the EPlus is very good, and is flexible and simple to use.
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> Dr. Li
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> To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> From: jeannieboef@...
> Date: Wed, 20 Jul 2011 10:56:03 +0000
> Subject: [EnergyPlus_Support] Re: EnergyPlus Model: Hydronic low temperature radiant system?
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> Chilled Ceiling Panels are always used in conjunction with monitoring the moisture of the air. the eplus object can be controlled to switch off if condensation would occur. From a user comfort point they are lovely...I sit in a office with this. Also, when combined with a well designed air supply inlet which strokes the ceiling, you can maximize the cooling effect. We typically run them on a 16/18 degC Chilled Water supply. Panels are grouped together (office-wise) with motor controlled valves.
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> --- In EnergyPlus_Support@xxxxxxxxxxxxxxx, YuanLu Li <yli006@> wrote:
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> > Changing the geometry is quite simple, because there are only a few objects involved.
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> > Once the geometry is defined by the OpenStudio or DesignBuilder, there is no real need to go back to them, unless you need to change the geometry again. The real usage problem will be the surface condensation. I have students in China tried using it on the ceiling. He had to feed cooled dry air into the room. So my question to him was why border to use the cool ceiling panel. It is practical for floor heating.
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> > Dr. Li
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> > To: EnergyPlus_Support@xxxxxxxxxxxxxxx
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> > From: jeannieboef@
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> > Date: Tue, 19 Jul 2011 17:17:55 +0000
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> > Subject: [EnergyPlus_Support] Re: EnergyPlus Model: Hydronic low temperature radiant system?
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> > Look up the Low Temp Radiant object in the excel sheet that is located in the documents/examples folder. It will point you to which example files use this.
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> > Pricipally it's easy to set up. But I find it a major work flow problem, because my geometery generation program (Design Builder) does not support radiant floors/ceilings. After exporting geometery, I have to make adjustments to Plant, Zone Equipment, Constructions and assign those constructions into the relevant BuildingDetailed objects.
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> > If I then have to make a geometery change in DB, the whole process starts over. If I have more than 7 Zones, this absolutely kills me!
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> > It also does't report nicely in the AllSummary report.
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> > What we need here is a Template that will work something like a negative ProcessLoad object that can be sized, controlled and coupled to the PlantLoop and report as a HVAC equipment. (perhaps without building it into a construction) These radiant panals are zone HVAC. We are not always dealing with "Betonkernaktivierung" or Activated Concrete Cores.
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> > --- In EnergyPlus_Support@xxxxxxxxxxxxxxx, Qianmin Zhang <zqianmin@> wrote:
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> > > Hello,
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> > > I read a paper and it mentioned the energyplus model of hydronic low
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> > > temperature radiant system, but I don't see it example files folder.
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> > > If there is not this model, any opinion of which model I could use to
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> > > present the chilled ceiling? Any idea of night sky cooling with a thermal
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> > > storage also? Thanks a lot.
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> > > Qianmin
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