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Re: [EnergyPlus_Support] Sensible Heat ratio in EPlus



This clarifies all of my doubts now. I appreciate both the approach. Thanks again for your time and effort.



On Mon, Mar 7, 2016 at 11:19 PM, Jim Dirkes jim@xxxxxxxxxxxxxxxxxxxxxxxxxxx [EnergyPlus_Support] <EnergyPlus_Support@xxxxxxxxxxxxxxx> wrote:
 

Oops. I just noticed Jean's post.  Everything he says is philosophical and true.  My post is the simplified version.

On Mon, Mar 7, 2016 at 12:47 PM, Jim Dirkes <jim@xxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
Javed,
ALL energy used inside the building becomes sensible heat with these exceptions:
  • the energy creates moisture (in which case it becomes latent load, not sensible)
  • the energy is taken out of the zone before it can affect the zone. This might be the case for:
    • cooking appliance energy removed by an exhaust hood, 
    • heat generated by a process inside a lab hood or 
    • process equipment heat removed by a condenser loop to the outdoors.
  • There may be other examples, but that covers the basic situations.
Unless your 2.2MW fits one of these categories, ALL of the electricity becomes heat after doing its work.  Another way to say it is that the work done by any device, electrical or otherwise, eventually becomes heat. A common example of this is fan heat, which you can see by looking at the air temperature before and after a fan. Less visible because it's small in magnitude, but the same principle, is pump heat.

On Mon, Mar 7, 2016 at 12:20 PM, Javed Iqbal eee.javed@xxxxxxxxx [EnergyPlus_Support] <EnergyPlus_Support@xxxxxxxxxxxxxxx> wrote:
 

Thank you, Jim.
I am trying to understand the basic thermodynamics behind heat generation from an electric equipment. For instance, we provide X amount of heat to an equipment and part of this will be converted into work and another part into the heat. In my particular case, I have 2.2 MW of electric load inside a zone. Does it mean that this whole will be converted into heat or part of this. Please correct me if I am wrong.. Thanks again.

On 07-Mar-2016 7:23 PM, "Jim Dirkes jim@xxxxxxxxxxxxxxxxxxxxxxxxxxx [EnergyPlus_Support]" <EnergyPlus_Support@xxxxxxxxxxxxxxx> wrote:
 

Javed,
Latent + Sensible + Lost = 1.0 ALWAYS
For electric equipment, it is possible to have latent (moisture) load; examples are a coffee pot and an electric humidifier.
If your electric equipment generates moisture and has sensible heat ratio of 65%, then I think the latent fraction should be .35.

On Mon, Mar 7, 2016 at 2:31 AM, Javed Iqbal eee.javed@xxxxxxxxx [EnergyPlus_Support] <EnergyPlus_Support@xxxxxxxxxxxxxxx> wrote:
 

Hi,

I am trying to simulate a internal equipment in a zone with a known sensible heat ratio that would be transferred to the zone air heat gain. I referred I/O reference file an found following are the three heat ratios types based on source type. In my case, Fraction latent and Fraction radiation is "0" as given in the specification sheet.  My question is what would be the correct value to simulate Sensible heat ratio of 65% in the following heat ratio objects?

Inline image 2

Inline image 1


â??Thanks,â??

--


Javed Iqbal, LEED AP, CEA
Sr. Energy Analyst 




--

James V Dirkes II, PE, BEMP, LEED AP
CEO/President
The Building Performance Team Inc.
1631 Acacia Dr, GR, Mi 49504

Direct: 616.450.8653
jim@xxxxxxxxxxxxxxxxxxxxxxxxxxx

Website l  LinkedIn





--

James V Dirkes II, PE, BEMP, LEED AP
CEO/President
The Building Performance Team Inc.
1631 Acacia Dr, GR, Mi 49504

Direct: 616.450.8653
jim@xxxxxxxxxxxxxxxxxxxxxxxxxxx

Website l  LinkedIn

Goodhartâ??s Law: â??Any observed statistical regularity will tend to collapse once pressure is placed upon it for control purposesâ??




--

James V Dirkes II, PE, BEMP, LEED AP
CEO/President
The Building Performance Team Inc.
1631 Acacia Dr, GR, Mi 49504

Direct: 616.450.8653
jim@xxxxxxxxxxxxxxxxxxxxxxxxxxx

Website l  LinkedIn

Goodhartâ??s Law: â??Any observed statistical regularity will tend to collapse once pressure is placed upon it for control purposesâ??




--


Javed Iqbal, LEED AP, CEA
Sr. Energy Analyst 



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Posted by: Javed Iqbal <eee.javed@xxxxxxxxx>


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