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[EnergyPlus_Support] Re: SWH?DHW Peak Demand Energy Use

Very interesting. Let's think out loud...Your system sizing is automatic in both cases which means they will both meet whatever demand your "demand side" (identical) asks. Since energy in (gas supply) equals energy out (DHW demand), assuming negligable energy conversion efficiencies, it makes sence that Ann. consumption is equal. 

Assuming one system needs a larger heat capacity than the other because of a more lathargic heat generation rate, it makes sence that this system with more "stored heat" will have a lower peak demand.

But how does one create this extra capacity in reallity? Storage tanks...where have you seen heat storage tanks? Maybe inside the boiler? Boiler size? In chilled water loops tanks are offen used to reduce chiller operation peaks or chiller on/off cycling. If you model has no tanks then the storage may be in the equipment size itself.

I have no idea how you set up your loops, so I'm just sound boarding a bit. Hope it gives you some ideas.

--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, Vinay Devanathan <vinay.devanathan@...> wrote:
>
> Hello All,
> 
> I have two models of which one is water-cooled chilling, and the other is
> air-cooled. I have DHW system modeled in both models similarly with same
> WaterHeater:Mixed, same WaterUse:Equipment and Connections, and with same
> Circulation Pump, and schedule. I get the same Total Annual Energy Use
> (Natural Gas) in both models, but the Peak Demand Energy Use is different,
> the water-cooled chiller has lesser peak demand energy use than the
> air-cooled model. Is this wrong or is it possible at all? Would the cooling
> tower dump heat to the plant loop which the DHW system might find useful? It
> would be great if someone can throw light on this.
> 
> Thank you.
> 
> Regards,
> Vinay
>




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