Martin Griffith

Hi Roy, you can make Ventsim calculate air densities from the gas mixture by turning on the option in Settings | Simulation | Gas | Use Gas Density for Air Simulation. With this on, the density in an airway will be calculated from the gas mixture present after a Gas Simulation. This density will be used in any subsequent Air Simulation, Heat Simulation and all of the psychrometric calculations for moisture content. I think this is what you are after. I'd be happy to take a look at this with you. We've been trying to push people to use Pumpsim for this sort of application, but this wasn't possible since Pumpsim 3.1 couldn't do what the Ventsim Gas Simulation does. This has changed with Pumpsim DESIGN, which allows similar Gas Simulations to Ventsim. Another comment on using Ventsim for this: the gas mixtures in the Gas Simulation are calculated for dry air. There is another setting, Setting | Simulation | Gas | Dry Air Gas Balance, with default setting of On. With this default setting, water vapour is ignored in the Gas balance (although it of course is integral to the psychrometric calculations). If you select No, then the software will calculate the amount of moisture in the air and then squash this into the gas mixtures; you will start to see a water vapour content in the Gas Simulation. This water vapour is not transported around the model in the same way as the other gas components, but is rather a straight function of the dry and wet bulb temperatures and pressure at the given location.

Hi, apologies, there have been some issues with our license server. Best to send us an email at ventsim.support@howden.com and we will take it from there.

Hi Myriam, Thanks for your post. Ventsim shows the speed as 0-100%, firstly because if the user doesn't enter a maximum RPM on the fan in the fan database, then that is all we can do. Then, if the user has defined a maximum RPM, we can't assume that the user happens to know the maximum, unless we add a new output for the maximum somewhere. So we still use the percentage. On the Edit Box, if a maximum RPM has been defined for the fan, the actual RPM can be read off the Fan info on the Edit Box. This way, in the image, it is clear to the user what the RPM is, but also that it is not running at maximum. Are you interested in the actual RPM as a Ventsim property as well? As for utility frequency, Ventsim doesn't need the utility frequency as part of the simulation, so it doesn't ask for it. It assumes that the user is managing it. I don't know how the max speed of the fan, or even the fan curve, changes with utility frequency, but I would like to know. The built-in fan look up tool asks for the utility frequency just so it shows you the correct list of fans, which are specific to a frequency. But this information is not recorded in the model when the fan is saved. For now, if you are working on a model which is expecting a change in utility frequency, then the approach would be to create duplicate fan definitions and adjust them appropriately for the different utility frequency. You would specify in the fan name or the fan notes which utility frequency the fan is defined for. Ventsim will not do this for you, so you would consult the fan manufacturer on how the fan performance would change.

Hi Asan, See some responses below: 1) You should be able to simulate multiple gases as part of the Gas Simulation. This is the main advantage of the Gas Simulation. Just configure your sources and run it. 2) There is currently no way to model radioactive gases other than radon (with the Radon Simulation). Nor are the decay characteristics customisable. Which gases do you want to simulate? 3) You can set multiple sources of different gases using the Gas Tab of the Edit Box, as shown in the image in point 1. 4) You can run the Gas Simulation and the Radon Simulation together if you want, but only in Dynamic mode, using the Multisim simulation option. There is no steady-state option. However, usually you don't need to do this. You can just run the Gas Simulation, then the Radon Simulation. This is because the concentrations of Radon and it's decay products are at very low levels of concentration. So extra Radon in the air will not have a big effect on the concentration of other gases. So you can run the Gas Simulation and then the Radon Simulation and get all your results, under the Gas and Radon property categories.

Hi Ozan, Which DPM properties are you dealing with? The yield rates of DPM? How are you determining these? Also, be sure to set the Diesel Power to the actual value, which matches the work output of the enginem, and not its peak capacity. If you want to send me a model, either here, or using the forum message service, or to ventsim.support@howden.com, we'd be happy to take a look. By DPF, you mean filters? Are these in the airstream, or on the vehicles?

Hi Marie, Airways levels are set by their existing elevation, which you can't change, except by moving the airways. You do have control over the levels though. Go to the Display Manager, open the Levels table and genereate some levels, either your own ones, or with the wizard. The Clip Level tool relies on the Levels you specify. Right click on the viewer and you will see the Clip Level option. Click it, then click on an airway.

Hi Xiao, You should be able to work with the dwg file. You may need to convert the reference graphic to Ventsim airways before you can start modelling though. If you like, send us the .dwg file and we can guide you on how to convert to Ventsim airways.

Hi Asad, No, there is no way of simulating a different decaying gas in Ventsim, like we do Radon. What do you want to model in this case? There might be something we can do.

Hi Sebastian, I think you just need to update tot he latest version of Pumpsim from here: Official Releases | Pumpsim And you will find this problem resolved. Thanks and let us know of any other problem you encounter.

Hi Sebastian, Could you please send us the model you are working on, and also tell us which version of the software you are using? And we will work out what has gone wrong. You can send me the model here through the Pumpsim direct message service, or email us, at ventsim.support@howden.com

Hi Haran, You should be able to open the dynamic monitor by clicking on it with the Zoom cursor (the magnifying glass). However, the graph will only open if there is data there. Have you run the Fire Simulation, or another Dynamic Simulation?

Hi, The fan capital component accounts for the effect the proposed change in airway size will have on the type of fan you require . In your case, reducing the size from 4.5m to 4.3m, will increase the resistance in the airway, meaning that you will have to increase the fan power to acheive the same flow. Therefore the proposed change involves a loss on the fan purchase. This is worked out purely by the extra power lost in ventilating the airway at the same flow rate, adjusting for fan and fan motor efficiency and then multiplying by the fan purchase cost. The friction power for a given airway can be seen in the Energy | Friction Power property. The power cost is the cost of the electricity to run the fan which is ventilating the airway. This is also calculated from the Friction Power in the airway, multipliying this by the number of hours over 5 years to get the energy usage in kWh, multiplying by the power cost of 0.12 $/kWh and then adjusting for net present value.

Hi, I see the problem. My suspicion is that the shapes have not been non-dimensionalized after importing. It is important to note that the profile shapes define the shape, not the size of the cross -section. It concerns me that your imported shapes look smaller in the presets window, they should all be roughly the same size. It looks like the imported shapes need to be adjusted to a non-dimensional size. You can do this manually by clicking on the shape in the Presets form, which opens the profile editor. Hit Apply on the editor and hopefully the shape will adjust. Let us know how that goes. We will investigate this further, so that this is taken care of automataiclly. If you can, could you send us your model and/or import file? You can do this through the forum direct message, or our support email ventsim.support@howden.com .

Hi. This warning means that you have two pipes connected that have different fluid types specified. Open your display manager, go to the Fluid Type tab and click on the color button. This will colour your model by the fluid type. Click on the error; this will zoom the viewer to the problem. You should see changing colours, indicating the different fluid types. Normally you wouldn't change the fluid type in a pipeline, so the warning appears. However, some users like to specify changing properties along a pipeline, to represent fouling, or sediment entering along the length of the pipe. Is this what you want? If so, it is possible to suppress the warning. If not, then you need to change the fluid type on the pipes so the match up.

Hi, We will have a look at doing this. However, we have been pushing users towards using message boxes for this. With these, you can edit and add your own text around data in the message box. If you get the very latest version here, it will also add the variable text automatically. Let us know how you go.

Hi Frédéric, Sorry you've had this problem. It's hard for me to work out what has gone wrong. I've done some testing and it seems to be working for me. Would it be possible for you to send me one or both of the models? You could send to me via the forum direct message service, or email me at ventsim.support@howden.com . And we will work out what has gone wrong. Otherwise, send me the version number of the software you're using (Help | About) and some screentshots showing the problem.

Hi Frédéric, Thanks for your question. After sorting the layers automatically, to get back to the original order by creation, you should be able to go to the Edit menu of the Presets form, and click on Sort by Index. This will sort the preset in the tab by the index order, which will match the order of creation. However, testing it now, it appears this tool is not connected to work on the layer presets. I think this is a bug in the software. We will fix it for the next version of Ventsim. The idea of grouping references has come up before and is something that we want to do. We have noted your interest and will seek to do this soon, perhaps in the next maor release. regards, Martin

Hi Frédéric, You can use the File Compare tool, which is found in the File menu. This will highlight airways that are different in the current model to those in the file you select with the tool. Let us know how you go with that option.

Hi Nathan, Apologies for this, but the link the button goes to is not working properly and does not show the correct fan information. In the current version of Ventsim we have temporarily disabled this button. We are working on getting the link working again. Furthermore the recommend fan tool is being re-released soon and will contain a broader selection of available fans. If you want information on a particular fan, you can contact us or Howden fan sales and we will provide you with any information you need.

Hi Agung, Sorry you've had this problem. Firstly, I would upgrade to the latest version of Ventsim, that you can find here: Patches | Ventsim This may fix the problem. Then, I recommend you go to your presets, do a right-click on the grid and select to Reset Default Presets. This should correctly re-establish the presets. Then I recommend that on the main Ventsim window, you go to File | Defaults | Save, to resave the new presets as your default. Also, if you can, please let us know what your keyboard and region settings are.

Hi Fred, Thanks for your enquiry. We add a new language to Ventsim mainly as a function of the interest we detect, through messages such as the one you've just sent us! I take it you would be interested in a French or Turkish version? There has been talk of making a French version, so that may happen soon. There is a fair amount of work to do to add a language. Also we need someone of course fluent in the language and with some knowledge of the field and appropriate vocabulary. If you're interested in participating in making a translation please let us know.

It’s time for another post about what’s new in Ventsim. What’s below builds on what was shown the last time I did one of these posts (New in Ventsim 5.4 - Ventsim News - Ventilation & Flow Simulation Forums (invisionzone.com) and what we showed on the release of Ventsim DESIGN 5.4 (What’s new in Ventsim 5.4! | Ventsim) . Most of this is based on your feedback and questions, through support, meeting you at conferences and training courses. So please get in touch if there is something that you’d like to see in Ventsim that we haven’t thought of yet. Get the latest version here! : Patches | Ventsim Waterways Based on user feedback, we’ve made some recent improvements to the Waterways feature. Extra features include the ability to set different flow rates at the start and end of the waterway; the solver will then add in extra water along the waterway. You would do this in a situation where you have regular ingress of water along the path, with the volume increasing over distance. We’ve also added an option to cut the latent heat from the waterway, which can serves as a rough model of a waterway with a cover. Heaters We’ve made improvements to the Heater function. We’ve improved the calculation to correctly handle moisture from the heater from the Direct Burner option. Also, we’ve added an option to run an Electric Heater, on top of the existing option of Direct and Indirect burner options. Of course this reports the electricity usage, rather than the fuel usage, both on the Edit Box and in any graphs from the Annual Flywheel Heat Simulation. We’ve also made the Direct Burn option add gases during a Gas or Diesel Simulation. Reporting We’ve made improvements to the summary form, which now can report Production from any Stoping or Development Advance Rates that you’ve added to your model through the Heat tab of the Edit Box. Colour-blocking You may have noticed there is now an extra button on the Display Manager. This is a toggle for going between blocked and graded colours. Click it on and off and it will make sense. This is useful for when you’re interested in hard boundaries and thresholds on properties, such as maximum allowable velocities or gas levels. Diesel and DPM improvements We’ve been working on the Diesel Simulation, as it’s something we hear about a lot. Run your Diesel Simulation and it will automatically track the usage of fresh air by diesel sources. This is a great way of tracking the local usage of air and whether the (common) 0.06 (m3/s/)/kW requirement of fresh air for diesel machines is being satisfied locally. For jurisdictions which don’t use this airflow requirement method, it still gives you an idea of the fresh air usage in your mine. The fresh air deficit warning will appear wherever a diesel source causes the Fresh Air Surplus to go below zero. We’ve also added properties for dynamic maximums and averages of DPM from the Dynamic Simulation. This is for those users who are running Dynamic Diesel Simulations with moving diesel sources and want to get an idea the temporal variations of DPM, in comparison to the steady-state Diesel Simulation. Automatically generate stages from airway ages. We’ve added a feature to the Stage Menu that will assign the selected airways to a stage based on the Simulation Year of the stage and the data mined of the airway. This is a great way of quickly generating stages over the lifecycle of the mine. Convert Overpass For those users who can’t get enough of the Convert to Overpass tool, we’ve made it so it works on already intersected airways. This gets rid of the hassle of deleting and redrawing airways when wanting to create an overpass from existing airways. Advanced Message Box Based on feedback, we’ve made the Advanced Message Boxes more intuitive and streamlined; now the message automatically generates text for you. That's the main improvements, but there are of course a range of other improvements and bug fixes throughout, so we encourage you to update to the latest version. As always, any questions, you can respond here or contact us at ventsim.support@howden.com. We rely on your feedback to make the software better, so please tell us if there is something you would like to see in Ventsim.

Please let us know how it goes.

Hi Andrew, you should be able to load VNETPC files in Ventsim. If it's not working, then I recommend sending us the file at ventsim.support@howden.com and we will work out what is going wrong.

Hi Andrew, sorry you had this problem. Is it still happening? If so, I recommend reinstalling from the website and trying again. If it persists, please contact us again. Patches | Ventsim