Martin Griffith

Hi Shane, Thanks, I'll take a look at this and get back to you.

Hi Stephanie, Please update to the latest version of Ventsim, version 5.4.3.0, available at our website: https://ventsim.com/download/currentdownloads/ Then select the Convert Floor Lines tool, and drag a fence with the mouse over the floorlines you want to convert. Do a small portion at a time, rather than the whole model at once. You can then use Tools | Filter to clean up, join and reduce airways.

Hi Shane, As always, really appreciate the feedback. The coordinate save issue for multiple airways has been fixed; we've just today pushed out version 5.4.3.0, an official release, so users will be prompted to update. Thanks for the suggestion on the Clear button. We will have a discussion about including a Clear or Reset button for different fields. It doesn't fit as neatly in the current grid format as it does in the old form, so we might have to get creative. I will keep you posted on any updates we make.

Hi Bruno, they are all available on our website here: https://ventsim.com/webinars/

Hi Glenn, you won't get contaminant or gas movement in an airway with no flow. So if there is zero flow, then you need to create some. If you are using the steady-state solver for this and you have a little flow, you could reduce the setting in Settings | Simulation | Airflow | Allowable Air Error, which will reduce the threshold below which contaminant transport is not calculated.

Hi Roy, the new Ventsim DESIGN version 5.4.2.8 has a fix included which copies groups of ducts, waterways and conveyors to new groups if you duplicate them. https://ventsim.com/download/minor-releases/ Thanks for the suggestion.

Hi Kingsley, thanks for your question. Firstly, the equation behind the orifice does not use an hydraulic diameter, it calculates the shock loss based only on the ratio between the orifice and and airway areas. There isn't any consideration of the shape or hydraulic diameter of the orifice. While the shape of the orifice will have an effect on the shock loss, we don't model it in Ventsim, since the area ratio will generally be the greater determining factor. You've included a picture of the Regulator Resistance option; a note of caution about comparing the orifice and regulator resistance options. The orifice has its own equation which relies only on the orifice-airway area ratio. We made the decision that Regulators only reference the Regulator area and not the airway area. For example, if you want a fully-open regulator of 16 m2 area in a 5.0 x 5.0 m2 airway to give the same result as a 16m2 orifice, then you need to provide a Regulator curve that gives that resistance at 100% open. This means that your curve for a 16 m2 area regulator is actually for a 16m2 area regulator in a 5.0 x 5.0m2 airway. The reasoning is that normally the shock or resistance curve of a regulator is not provided; usually it is obtained by the engineer taking measurements across the regulator at different openings and entering the curve in Ventsim themselves. If you do this then you can simply enter the total resistance measured, without having to work out yourself what proportion of the shock loss is due to the regulator-airway size ratio (which Ventsim would calculate) and what is due to the opening of the vents (what you would enter in the curve). This is different to the orifice option which is based only on the orifice-airway area ratio. I hope this helps. Let me know if you have more questions.

Hi Kevin, Glad to hear it's sorted, please let us know if any other problems comes up.

You can drag and drop images from the Windows File Explorer into Ventsim. You can drop them on the background. But you can also drop them on an airway and the image will be saved to the airway. In this example, I've dropped the image on the airway and now it's saved as part of the Airway Notes. You can also write text here which will appear on the airway. You could use a picture in this way to represent a refuge bay. You may already be aware, but Ventsim now has a tool to add refuge bays (and an icon), from which you can also calculate Escape Routes to, as well as calculate across the model the distance to refuge bay and surface. You can also drop images onto the Presets. You can drag and drop an image on to a Resistance, Regulator, Fan or Heat Icon (representing a Preset) in the viewer and it will save with the Preset. You can also do it directly through the Presets form by clicking in the Icon column for the Preset. There are examples of this in the demonstration models: in the Metal Mine, a truck image is saved with the Truck AD55 Heat Preset; another example is on the Fans of the Coal Mine demo. Hope this is what you're after, let us know.

Hi Roy, Does the model take into account the difference in cooling from a thicker pile i.e. the skin cools faster than the core ? Yes, this is correct. The Ore Thickness and Thermal Conductivity (from the Rock type) are used in determining the heat transfer coefficient; the thicker the ore, the lower the heat transfer. Additionally, this thickness (along with the width) is used to represent the conveyor visually in the viewer. If I copy the conveyor and attached airways (e.g. a belt road) in wire frame then all the airways and links are copied BUT the two conveyors are linked as a group. This puts twice as much heat into BOTH sets of attached airways We will make a change so that old groups aren't extended when duplicated. The change we made previously does this, but only if every airway copied belongs to the same group (which is not the case when conveyors are being copied along with their partner airways) However, I couldn't come up with a case where the heat was added twice in each set. Are you able to send me an example of this?

Hi Roy, It is set up so that only visible airways will have the changes applied; hence the need to go to Wireframe first. We added some checks so that now Edits are applied to visible airways and also to invisible airways that would have been visible if Wireframe mode had been enabled. This means that when you select/edit in Solids mode, the changes will be applied to the Duct Leakages. We also added some checks to avoid changes being applied through the Edit Box to the Duct Leakages which would incorrectly alter their function (such as size and resistance changes). The new version with this change is available here: https://ventsim.com/download/minor-releases/ Thank you for the feedback on this. Please let us know if there is any problem with it

Hi Juan, Calibrating the model against surveys is very important. However, a good idea is to first make sure that you're model is correctly configured before you start making adjustments to match the surveys. For example, it is not ideal if you correct the flow in an airway by adjusting the friction factor, when in fact you have the incorrect airway size entered. Because there is so much input data to a Ventsim model, it is possible there will be some errors. A good place to start is the Audit Tool (Tools | Audit Tool). This will take you step by step through your model, advising you what to check in your model. It will even compile a check list of things in the model that need to be revised. Give it a go, and let us know if you have any problems.

Here is a first draft. It still needs more work, there are some colours that are not completely clear and we may need to tailor the text border colour for certain colours. Any thoughts, please let us know.

Hi Roy, Thanks for the suggestion. We're going to give it a try and see what we can do. I'll keep you posted in this thread on any updates or progress we make.

Hi Andrzej, A new version of Ventsim 5.4.2.4 is available here: https://ventsim.com/files/vvsetupminorrelease54.exe with this issue fixed. Thank you for contacting us about it! Don't hesitate if you have any questions.

Hi Andrzej, thanks for contacting us. There might have been a reason at one point why this wasn't possible, but I think it should be ok. We're making a change to allow these heat sources to work during Dynamic Simulation. We will release a new version with this fix today or tomorrow; I will post here again when the version is available.

Hi Roy, we've made this change in the just released version of Ventsim 5.4.2.1, available here: https://ventsim.com/download/minor-releases/ Ventsim will now not report Invalid Preset errors on Excluded Airways. Thank you for the feedback and suggestion!

Hi Roy, we've made this change in the just released version of Ventsim 5.4.2.1, available here: https://ventsim.com/download/minor-releases/ Ventsim will now not report Invalid Preset errors on Excluded Airways.

Hi Claudia, this issue is fixed in the just released version of Ventsim 5.4.2.1. The message is replaced with a temporary message of a few seconds. Thank you for the suggestion.

Hi Jorge, thanks for your question. Pumpsim does include the atmospheric pressure in the NPSH calculation. The atmospheric pressure is configurable in Settings | Simulation | Environment | Surface Pressure Barometric. The default value is 1.01 bar. You can change this value and this will affect the pump NPSH checks.

Hi Roy, The Invalid Preset Error is an error (red), rather than a warning (yellow), so will itself cause the Simulation Fail. We've made a change so that Excluded airways are not checked for Invalid Presets, which should do what you're after. I'll post here again when the next version is available (probably tomorrow).

Hi Claudia, Thank you for the suggestion, we will have a look at doing this for the next version.

Hi Roy, we will have a look at doing this. We might add a settings option to ignore warnings on excluded airways. I will reply here again once we've done something.

From the Ventsim manual, the similar parameters available are: We will take a look at the Thermal Discomfort Index.

Hi, thanks for your question. Generally we recommend only using the Filter tool after the creation of new airways and before any breaking up of the model into different stages. The Filter tool has a few checks built in to it which will prevent any Filter operations changing any other Stages. For this reason it unlocks the locked Stage if it is launched.