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Re: [EnergyPlus_Support] Modelling Cleanroom HVAC in Energy Plus





Okay. EnergyPlus can simulate all these HVAC systems. Fan energy consumption is a function of the flow required and the pressure that the fan has to overcome to move the required amount of air. If only the yearly energy consumption is interesting you may assume an equivalent pressure of the filter that will be result in the same energy consumption. For example a typical F7 filter would have a clean pressure drop of 90 Pa and get exchanged at 120 Pa. If you assume the filter's yearly average pressure drop is 115 Pa you're energy error margin would be smaller plus minus E=flow_m^3/s x 15Pa. 

As you see the amount of energy error for dynamic filter simulation is negligible for normal air handling units compared to heating and such so we never put much thought into it.  A hepa filter or cleanroom filter may have larger pressure drops making the effect more significant but it depends on the pressure change allowed before you have to change filters anyway. 

If you've done your duct hydraunic calc you could most likely tell the energyplus fan component what pressure it has to overcome possibly as a yearly average. 

A good duct design should land you at an external pressure of about  400 Pa. The air handler has additional internal pressures to overcome like filter, sound attenuator, heating coil, heat recovery device, etc. that land you at the 1000 Pa mark. 

You could use a manufacturer software from SystenAir or Flaktwood to spec the AHU. This spits out a data sheet with key info you need to populate the parameters for other components...before trying auto sizing.  

Do you have any special supply diffusers or extraction units


On 31 May 2018 2:17 pm, "kwesi mensah kwesimensah7@xxxxxxxxx [EnergyPlus_Support]" <EnergyPlus_Support@xxxxxxxxxxxxxxx> wrote:
 

Thank you for your response. Very insightfull.

1. For the kind of results, for now, am investigating the energy consumption for the Heating system (Boiler or Electric Heater) and cooling system (chiller water system or direct expansion), humidification system and or dehumidification system, fans, and pumps for maintaining the setting points conditions in the cleanroom model.

2. For the filter system, I want to find the dynamic pressure drop across the filters in the duct. In any case if i know how to model the basic static or fixed state of filters considerinf the efficiency, that will be great aswell. 

3. For now, am not considering or monitoring contaminants and CO2 levels in the air.  Am only going to assume basic setting conditions (temperature, humidity, and pressure) in the clean room as a model, while i observe the energy consumption of the HVAC equipments. 

Any suggestions on software program that can 
Best model these requirements will be appreciated aswell.

Thanks in advance.

Best regards
Kwesi

On Thu, 31 May 2018, 7:36 pm Jean Marais jeannieboef@xxxxxxxxx [EnergyPlus_Support], <EnergyPlus_Support@xxxxxxxxxxxxxxx> wrote:
 

What results do you need
Why energyplus
What aspect of the filter do you need to model
Do you need to monitor contaminants in the air in the ducted air system
Or is only the room important 
Do you need to consider the pressure drop of the ducted system dynamically or is a fixed state acceptable 
Are you monitoring human comfort
Typically clean room design requires CFD because the zone air is not supposed to be well mixed. Rather flows should be laminar as possible and very well directed

Jean


On Wed, 30 May 2018, 16:43 kwesi mensah kwesimensah7@xxxxxxxxx [EnergyPlus_Support], <EnergyPlus_Support@xxxxxxxxxxxxxxx> wrote:
 

Hello Snr Enginners,

I am a beginner in EnergyPlus. 

My task is to model the energy consumption of HVAC system in a 1 zone cleanroom using energyPlus.

The AHU will have basic components as follows ((Boiler, Chiller unit, humidifier, heat extraction unit, and total heat recovery heat exchangers and Filters) 

I tried glancing through the example files in energy plus but unfortunately i couldnt find any related with Cleanrooms cleanroom.

Please is there any one who can share an example file with me if any?  Or help me with an information or materials to assist me in this regard?

Also i will like to find how usually, an Air Filter (HEPA and ULPA filters) is modelled in EnergyPlus.

Best regards
Kwesi

 


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Posted by: Jean Marais <jeannieboef@xxxxxxxxx>


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