Roy Moreby

OK thanks - must have been me - worked when I reloaded the file

Hi Martin Another one that I may have not understood correctly I want to show added sensible heat and moisture in a data box (see attached) I have added 550kW sensible and 165 ml/sec as a defined preset I have used what I assume would show this - the heat one works but the moisture does not Any suggestions? Regards Roy

Thanks - got it

Hi Martin and Co This may not be a bug but I cannot see what I am doing wrong ? I use the spreadsheet a lot for analysis using unique airway names with Vlookup() in Excel to get relevant data If I type in an airway name then is shows up in the spreadsheet under descriptors - all good However, if there is a Heat preset that I have named (e.g "Dev Belt") then it shows up in the same airway name column - I cannot see an option to have a separate column for Heat preset names? Also - if I name an airway AND it also has a named heat preset then the airway name shows but not the heat preset Any chance you could set it up so that the Airway Name option is always only the airway name and there is another column option for the Heat preset name? This issue may apply to other named presets? Thanks

When you turn off a fixed flow - restrict only you still get a waning if fan pressure is requried Any chance you could change it so that these warning are not given if the fixed flow is in fact turned off - not a big deal just spend time checking for errors that are not there Thanks

Hi Any chance you can add Data Box to the clone options to avoid having to add them via the airway edit form Thanks Roy

Thanks

Hi There is a repeatable bug in stages If I am say stage 3, duplicate an airway then change it to stage 4, Ventsim also adds it to stage 1. If you forget to check then stage 1 gets cluttered with all the airways you didn't intend to be there - make sense? Thanks Roy

Hi Ventsim There appears to be a error in the calculation of radon progeny concentrations with time. I have run this on version 5 and 6 and get the same error Attached is a graph showing the theoretical growth of radon progeny per 1,000Bq/m3 Rn (1Bq/l Rn) The maximum radon progeny concentration is about 5.6uJ/m3 after about 200minutes This also gives you the equilibrium factor i.e. about EQF= 1 at 200 minutes. Slightly different if you include decay of Rn gas I have tested this by putting 25,000Bq/s into 25m3/s in a 5m x 5m airway i.e. 1.0m/s - see model attached I have then used different airway lengths to test the radon progeny concentrations e.g. 60m = 1min The results show an ever increasing radon progeny concentration with time - see attached table When I plot the Ventsim results with time against the theoretical values (Bateman Equations) I get the following. This indicates a divergence of theoretical v Ventsim after about 70mins. This is a significant difference in air passing through old workings or cave piles. Could you take a look at this please Thanks Roy Radon Test.vsm

Ooops Sorry - found it in Attributes

Hi Can you add Fan and Fixed options to the spreadsheet data column options? Useful when turning fans on or off or changing speed in various stages in a multi shaft mine Thanks Roy

Hi Martin Found a bug (I think) When I run a model with air (i.e. no gas specified) and fix the flow rate on a mass flow basis it works fine When I set the inlet to some gas mixture then fixing the mass flow produces a wrong answer e.g. I fix at 1kg/s but Ventsim changes that to 0.81kg/s The mass flow rate of dry gas should stay the same if setting the mass flow as a fixed number i.e. if I have 1kg/s of CH4 then the quantity will change with pressure but the mass flow rate should not. I also see that if I run vent first to balance the network, then gas then vent then repeat a few times again it keeps changing the mass flow rate It also takes three complete iterations to get the mass flow right with the gas turned off Thanks Roy

Hi Martin FYI, I have started getting this error message as well this week Also note, that on my laptop it says that the licence is already released but in reality it has not been released as it is still active on my desktop I have emailed support Roy

Thanks Martin - sounds perfect

Hi I am using ventsim to model various gas management systems in coal mines in which there will be variable mixtures of air and gas (CH4, CO2 and N2) at various pressures (down to -50kPa guage) and temperatures. Due to the wide range in densities involved, I prefer to model on a mass flow basis. Please clarify if the various Ventsim algorithms account for various gas mixtures when specifying mass flow rates and also if calculating moisture content from wet and dry bulb temperatures. The temperature/moisture content aspect my sound pedantic but it is a significant issue in coal mine monitoring systems when calculating actual CO2-e emissions from sampling of "wet" or "dry" gas streams. At one mine this made a difference of about AU$1M per year!!! Thanks Roy

Hi Ventsim I am trying to model a cryogenic cooling system which will require temperatures to be as low as -196C - using the method of setting discharge temperatures after evaporation of liquid air. It appears that the lower Ventsim limit is currently -100C - I tried all methods but it always comes back to -100C Any chance you could change the limit to say -200C ? I need this quite soon - any chance of a quick patch? Thanks Roy

Hi When you save a the next version of the user manual as a pdf, is it possible for you to save as a pdf with bookmarks. When I save a word document as pdf I use "Save as Adobe pdf" rather than "Save as" then "pdf" - this adds all the section headings as bookmarks. I have a full but out of date version of Adobe, when I open the manual there are no bookmarks so I can only navigate the document using ctrl-f (for find) or going back to the contents pages. Bookmarks would make it much easier - unless I have missed an option here? Thanks

Hi Craig Fixed it when I updated windows - never did work out what was wrong Thanks

Hi Martin and all I work between a laptop and desk top with only one licence. If I release the licence on one then I can activate on the other - all good However, if I forget and try and use the Licence Manager - Request Licence Release, it now says - "cannot communicate with server". This has been the case for a couple of months - obviously I am connecting with the server because it allows me to activate if I have released the other one. Please fix as I often forget. Regards Roy

Hi Martin - I think so, I am very used to the old button as it was so easy to use. I will give it a go thanks

Hi Maybe me being thick again - in the old edit box you could select a number of airways and make them unique to the stage you are in - a detached copy. Where is that option in the new edit box?

Hi 1/ When I open an existing file, all friction factor presets and icons are correct. 2/ When I open an airway edit box, again, all correct. 3/ If I go to preset screen and change order then press ok e.g. by number or name, this screen is correct 4/ If I now go back into an airway edit box, then the friction factor value is correct but the name in the drop down list is not 5/ If I select the correct name then it is aligned with the original value so cannot track what is being used in simulation. I then do not know what friction factor value is being used if I save the model. 6/ If I then reload the model without closing Ventsim, the problem remains 7/ If I close Ventsim then start up again then reload the model it is back to the correct pre set order and values. It appears that Ventsim looses track of the friction factor name and value if you re order. See attached - looks like the name is taken from the original location in the pre set table but the value is not This may be a problem with all the pre set lists? Thanks

Sorry - was a dumb question, I forgot about the text at the top of the scaling tool

Hi All This may be a dumb question but I cannot see the answer in the manual When drawing longwall goaves or hard rock mine stopes, I create a defined profile then draw the airway to length and set the height and width For a goaf, this could be 4,000m long, 300m wide and 150m high - works great. The important issue is how these voids interact or connect to overlying old workings. When using the graphics scaling tool, this alters the height and width but not the length. So, the question is, how do you set scaling so that all airway height and width are drawn 1:1 to match lengths? I noted that when I tap on the icon at the bottom of the scaling tool it appers to go close to 1:1 - is this what it does?

Thanks Martin