RE: [EnergyPlus_Support] UFAD and displacement use more energy for heating than well-mixed system

[Lixing Gu <gu@xxxxxxxxxxxx>]

Jean:

 

Sorry, I don’t have a good knowledge of either DV or UFAD. Someone in the team should have better knowledge. You may post this question in the helpdesk.

 

Thanks.

 

Lixing

 

From: EnergyPlus_Support@xxxxxxxxxxxxxxx [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of Richard Raustad
Sent: Friday, September 27, 2013 2:53 PM
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: Re: [EnergyPlus_Support] UFAD and displacement use more energy for heating than well-mixed system

 

Mr... or better yet, Dr. Lixing Gu

On 9/27/2013 2:48 PM, jeannieboef@xxxxxxxxx wrote:

Very specialist topic. I think Lixing is the best person to answer this one. She's the developer and has published somewhat on the topic.

 

You may also want to search the ASHRAE journal database for articles relating to DV and UFAD. It is easy both in reality and for simulation to set up a system where it can't work or so that it won't work. DV and UFAD, just like DOAS + Chilled beams are not one size fits all solutions. The phrase "hourses for courses" comes to mind.

 

Good luck.

Mit freundlichen Grüßen- Sent from my iPhone (excuse the brevity)

 

i. A.

Jean Marais

b.i.g. bechtold

Tel.   +49 30 6706662-23

On 27.09.2013, at 18:23, HJ <wanghaojie630@xxxxxxxxx> wrote:

 

Dear all,

I did a simulation and found that UFAD and displacement ventilation uses
more heating energy than well-mixed system. I read the engineering
reference and think UFAD and displacement will be modeled the same as
well-mixed system for heating. Only in cooling the temperature
stratification modeling is used. So does anyone have any idea why this
might occur? All the other conditions are the same.

HJ

-- 

Richard A. Raustad

Senior Research Engineer

Florida Solar Energy Center

University of Central Florida

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