[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [EnergyPlus_Support] VAV with 100% OA





Francesco,
Your schedule affects only outdoor airflow. Apparently you want to make a change in the total airflow, however.

I have never done this, but I think you may be able to do it with an EMS program.
Inline image 1

On Fri, Oct 9, 2015 at 4:55 AM, fpasserini.tn@xxxxxxxxx [EnergyPlus_Support] <EnergyPlus_Support@xxxxxxxxxxxxxxx> wrote:
 

I have created a very simple model, because I want to understand how I can model a VAV system where the ventilation rates are lower during the weekends and the air system operates always with 100% outdoor air (I don't want any recirculation).

During the occupation hours I want to have 1,00m3/s during week days and 0,10m3/s during the weekends, therefore I have imposed the following control:


Controller:OutdoorAir,

Air Loop AHU Outdoor Air Controller, !- Name

Air Loop AHU Relief Air Outlet, !- Relief Air Outlet Node Name

Air Loop AHU Extract Fan Air Outlet Node, !- Return Air Node Name

Air Loop AHU Mixed Air Outlet, !- Mixed Air Node Name

Air Loop AHU Outdoor Air Inlet, !- Actuator Node Name

1, !- Minimum Outdoor Air Flow Rate {m3/s}

1, !- Maximum Outdoor Air Flow Rate {m3/s}

NoEconomizer, !- Economizer Control Type

ModulateFlow, !- Economizer Control Action Type

, !- Economizer Maximum Limit Dry-Bulb Temperature {C}

, !- Economizer Maximum Limit Enthalpy {J/kg}

, !- Economizer Maximum Limit Dewpoint Temperature {C}

, !- Electronic Enthalpy Limit Curve Name

, !- Economizer Minimum Limit Dry-Bulb Temperature {C}

NoLockout, !- Lockout Type

FixedMinimum, !- Minimum Limit Type

mechvent pterra, !- Minimum Outdoor Air Schedule Name

On, !- Minimum Fraction of Outdoor Air Schedule Name

mechvent pterra, !- Maximum Fraction of Outdoor Air Schedule Name

, !- Mechanical Ventilation Controller Name

, !- Time of Day Economizer Control Schedule Name

No, !- High Humidity Control

, !- Humidistat Control Zone Name

1, !- High Humidity Outdoor Air Flow Ratio

Yes, !- Control High Indoor Humidity Based on Outdoor Humidity Ratio

BypassWhenWithinEconomizerLimits; !- Heat Recovery Bypass Control Type


where the schedule is


Schedule:Compact,

mechvent pterra, !- Name

Fraction, !- Schedule Type Limits Name

Through: 12/31, !- Field 1

For: Weekdays SummerDesignDay WinterDesignDay, !- Field 2

Until: 08:30, !- Field 3

0, !- Field 4

Until: 18:00, !- Field 5

1, !- Field 6

Until: 24:00, !- Field 7

0, !- Field 8

For: AllOtherDays, !- Field 9

Until: 08:30, !- Field 10

0, !- Field 11

Until: 18:00, !- Field 12

.1, !- Field 13

Until: 24:00, !- Field 14

0; !- Field 15


Since the air flow shall be independent from the cooling load and from the heating load, I have forced the air flow rates in Sizing:System.

As fan I'm using Fan:VariableVolume and as terminal AirTerminal:SingleDuct:Uncontrolled


If I consider the output, the outdoor air flow rate is modulated properly, but there is recirculation (the supplied air flow rate, i.e. OA + recirculated air, is constantly equal to 1m3/s).

I attach the model.

What is wrong?

Best Regards

Francesco





--

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

â???happiness is the joy produced in us by truth. To be truly happy means coming to know how things really are, experiencing ?reality in its ultimate rootâ??¦
What matters more to oneâ??s happiness than getting more freedom and power is the end toward which we order whatever freedom and power we have. Unless we order ourselves to the truth, more freedom and more power will bring only more unhappiness, examples of which abound.



__._,_.___

Posted by: Jim Dirkes <jim@xxxxxxxxxxxxxxxxxxxxxxxxxxx>


Primary EnergyPlus support is found at:
http://energyplus.helpserve.com or send a message to energyplus-support@xxxxxxxx

The primary EnergyPlus web site is found at:
http://www.energyplus.gov

The group web site is:
http://groups.yahoo.com/group/EnergyPlus_Support/

Attachments are currently allowed but be mindful that not everyone has a high speed connection.  Limit attachments to small files.

EnergyPlus Documentation is searchable.  Open EPlusMainMenu.pdf under the Documentation link and press the "search" button.




Visit Your Group
Yahoo! Groups
PrivacyUnsubscribeTerms of Use

__,_._,___