Program features Screen shots Detailed example Order Heavent

Industrial Exhaust Ventilation Software:

Heavent Selected Screen Shots

seguffey@gmail.com


SASDFG

 

Links to this screen
Setting up the program Defaults Toggles        
Laying out the system Schematic Modifying Layout        
Inputing parameter values QuickInput EstimateAirflow Air Cleaning Device Fan Conditions Psychrometrics Specialized Input Screens
Optimization Parameters On Schematic        

 

System Schematic Screen

You "build" the duct system by connecting the links together. It is much easier, faster and forgiving than you would expect. By clicking on the buttons below that show the duct id number, you engage a drop-down menu that allows you capabilities that are unimaginable without Heavent.

schematic large

  • The program allows you to input the most common system effects on fan performance.
  • The program also computes the pressures and flows you otherwise would look up on a fan table (they are not the same as the actual flows and pressures because the fan tables are determined for ideal, standard conditions). Note that building pressure also affects the fan pressure.
  • When ordering a fan, you should give the inlet and outlet pressures and let the vendor rep make the fan selection, but it is nice to understand what is going on.


Modifying a Duct Layout
back to top

  • A Popup menu appears when you click on a duct ID number. Among many other choices, you can add or disconnect ducts or air-cleaning devices.
  • Keep adding air-cleaning devices, junctions of ducts, and ducts until the schematic matches the proposed system. Note that it is a schematic, not a to-scale representation of the system.


Toggles: Choices about how Heavent works back to top

  • Modeling predicts effects of altering installed systems
  • Flows can be adjusted with dampers using a revolutionary field adjustment method
  • [Other choices are explained in the manual]

capturing hood

Defaults: Minimize User Inputs

Duct characteristics tend to be much the same across branch and submain ducts. The Defaults screen lets you input the default values that will be automatically assigned by Heavent, including target airflows (Q), duct temperatures and humidities, duct lengths, elbow curvatures, junction entry angles, duct roughness and gauge, and loss coefficients for hood entries, elbows, etc. If a particular duct has different values, you enter them in the Quick Entry screen. The defaults generally will decrease the necessary inputs by more than half.

  • Setting defaults for a system reduces the number of necessary user inputs
  • Values can be changed as often as you like
  • Can over-ride previous inputs with default, if you wish
  • [Downstream and upstream offsets allow the program to compute values at locations where you can measure them]

Note that all inputs, including for defaults are examined by Heavent to be certain they are both valid and reasonable. However, unless your input is physically impossible, you are the boss and Heavent will let you over-ride its judgments.





Estimate Airflow Requirements for Common Hood Types (Two Examples)

For some common, simple hood types, Heavent can estimate the airflow requirement based on conditions and the hazard of the potential exposure.

Benchtop Enclosures

capturing hood

Capturing Hoods

Fan with elbow at inlet


Quick Input Screen

The two screen shots below represent most of the width of the data input screen (it scrolls left and right as well as up and down). Heavent minimizes user input errors on all screens by subjected each entered values to tests of plausibility, providing feedback on the table when a value cannot be correct and when it is simply unlikely to be correct. Those tests are highly sophisticated, making use of physical limitations and likely choices in real systems for each inputed value.

Note also that on any screen the user can switch back and forth between US common units and the metric system. Heavent recalculates all displayed values for whichever unit system is current. Input tests of validity are based on the unit system in use at the time of input.

  • Data inputs minimized by user-settable defaults (see Defaults above).
  • Nearly all data for ducts can be inputed from the spreadsheet-style QuickInputs screen or from screens customized for particular sets of data inputs (e.g., hood losses, elbow losses, etc.)
  • Temperature and humidity requires no user use or knowledge of psychrometric tables or charts (Heavent does it all by computation).
  • As you change conditions, the program continues changing the duct diameter for round ducts so that the duct velocity exceeds the minimum (target) duct velocity. If you turn off automatic duct sizing in the Toggles menu, Heavent will make only the initial duct diameter selection, leaving changes to you. You also can fix a particular duct's size by selecting "Fix duct size".
  • Help screens show almost all loss coefficients you will ever need.



Showing different parameters on the schematic

  • Selecting "ShowValues" from the Schematic screen's bar menu brings up the drop-down menus below. You can chose to show any of those parameters on the schematic instead of the duct ID numbers.
  • The most important parameters to show are "%Airflow" and "%Velocity." You will wonder how you ever got along without this feature (and program) before!

lasjdf

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Specialized Data Input Screens

Its should be rarely necessary to use the screen below instead of inputing the same values in the Quick Entry Screen..


Likewise for the screen below.

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Estimate Pressure Requirements for Air-Cleaning Devices

Heavent estimates static pressure requirements based on the type of device, the airflow through it, and the temperature and humidity of the air passing through it.


Fan Inlet Conditions ("System Effects")

Poor fan inlet or outlet conditions can increase the rotation rate and fan power requirement. Heavent computes those effects based on inputs from the user concerning conditions upstream and downstream of the fan. You need not consult any tables.

  • The program allows you to input the most common system effects on fan performance.
  • The program also computes the pressures and flows you otherwise would look up on a fan table (they are not the same as the actual flows and pressures because the fan tables are determined for ideal, standard conditions). Note that building pressure also affects the fan pressure.
  • When ordering a fan, you should give the inlet and outlet pressures and let the vendor rep make the fan selection, but it is nice to understand what is going on.

Fan with elbow at inlet

Of course, if you have ideal fan inlets and outlets, no corrections are necessary (Finlet 0 and Foutlet = 0 .

 

Psychrometrics

Effects of altitude, room temperature and room humidity are the same for all hoods. You take care of that using the Default Menu. Occassionally, some hoods will have a different air temperature and humidity than other ducts. Dry bulb and wet bulb temperatures and humidity mass ratio can be inputed along with duct information and Heavent takes care of their effects for you. If you need to determine humidity variables, this screen can provide useful information.

  • You simply input the desired dry bulb temperature and the wet bulb temperature or relative humidity. The program computes all other values for you.
  • When you inputed altitude in the Defaults menu, you did all you need to do for altitude effects. The program takes care of the rest behind the scenes.

Fan with elbow at inlet

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Help back to top

  • Each screen has its own Help menu, which explains the purpose of the screen and all the options presented on it.
  • You can do things in any order you choose, but it is most convenient to do things in the following order:
    1. set defaults to reduce the number of necessary inputs
    2. choose or create a file of available duct diameters
    3. build the schematic of the system on screen
    4. input data
    5. tweak duct size selections
  • Remember, you can do things in any order. The order above is by far the most convenient, but the program doesn't care what order you input information -- or how often you change your inputs or the system schematic.
  • A "Navigation" Screen will help you do things in the order shown above. You may find that assistance helpful until you understand what you are doing.


Example Help Screen

A few screens are needed because Heavent makes the great majority completely unnecessary.

capturing hood

 

 

Another View of the Schematic

schematic 2

SASDFGFunctional except cannot save files

 

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 Steven E. Guffey, PhD, CIH
1403 Far Meadows
Morgantown, WV 26508
(304) 685-1298
prefer email or text message to voice mail
Internet: seguffey@gmail.com

 

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