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Green Building Bible, Fourth Edition
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    •  
      CommentAuthorfostertom
    • CommentTimeAug 20th 2008
     
    Posted By: ali.gillIn any product review one of the key indicators is price and with hot3000 being licence free and open source surely that puts it head and shoulders above the others.?
    Cut-down IES now seems to be free download for Revit, Archicad has Ecotect built in and Tas will presumanly become integrated into Bentley/Microstation.
  1.  
    "Archicad has Ecotect built in"

    Unfortunatly not! Ecotect was bought by Autodesk.
    v5.6 of Autodesk Ecotect has just been released, although there is a plugin for Archicad.

    http://www.squ1.com/products/ecotect
  2.  
    Posted By: ali.gillwith hot3000 being licence free and open source


    Just a small nitpick here: hot3000 is not licence free, it is released under the Gnu Public License which grants users specific rights and permissions.

    One of the interesting aspects of the ESP-r engine that underlies hot3000 is that it has been verified against real test buildings in many different climates. Of course, it is still a model and, as such, is subject to refinement due to feedback from real test data. One recent example was the incorporation of a model of radiator placement and verification of this with the two test houses at the Canadian Centre for Housing Technology (see http://www.esim.ca/2001/documents/proceedings/Session7-2.pdf for the paper).

    Paul in Montreal.
    •  
      CommentAuthorfostertom
    • CommentTimeAug 20th 2008
     
    Posted By: bot de paille"Archicad has Ecotect built in"

    Unfortunatly not! Ecotect was bought by Autodesk
    I see - a year ago, it was 'strong links' being reviewed - the first mention of any such in AEC Mag - but things worked out different!
    •  
      CommentAuthorali.gill
    • CommentTimeAug 20th 2008
     
    yeah i saw that about ies tom, but like you say its the cut down version and only using the revit plug-in - see link.
    http://www.iesve.com/content/default.asp?page=s133

    autodesk offer a 30-day trial of revit- but i dont see much value in that as the software is so vast that even 30days doing nothing but revit would barely skim the surface of what its capable of. i think the period should be extended to 180 days so at least when you invest in revit you have a means of recouping the investment straight away by using the revit software rather than using an alternative software to complete jobs to create the revenue to pay for revit while you are still learning it.
    http://usa.autodesk.com/adsk/servlet/index?siteID=123112&id=8496703

    You're right to ntpick Paul that was me being lazy and definitely needs more research as i think tom queried before whether the 'rights and permissions' include commercial use.

    That reminds me i did have a point to make... being that the ies offer, 'free plug-in', is quite limited in depth but serves to capture autodesk users that are probably loyal to the software they use, hence capturing that loyalty by association.
    Also with many individuals and companies being averse to change the brand of software being introduced into and supported by universities will play a significant part in the growth of a particular softwares user base which will then impact availability of skills, salaries, company choice of software, etc.

    So going back to the original question, (thread title), the answer will depend on the perspective or position of who's asking.
    a self-employed individual would want maximum return on the investment and to achieve a unique selling point. - so tas might be most suitable if entering the epc market and hot3000 for accuracy of design representation (if the commercial use licence agreement is amenable).
    an architecture student or employee would want to improve accessibility to the job market . - so ies.ve with its ties to the rapidly developing revit is probably most suitable.
    a building services or environmental consultant might look more at tas for accuracy and career longevity as it is well established in this field.
    an educational institution would want ease of use for rapid learning and turnaround of productive work, hence designbuilder.

    is that a fair summary?
  3.  
    I think its a very good summary. I've used and taught AutoCAD ArchiCad Revit and Tas though know very little about the others really

    I still see great difficulties in trying to tie them up together - they are so unlike each other [apart from AutoCad and Revit] Even if I could inport a 3D model into Tas I would not do so. The front end of Tas is now much improved [finally] Most of the bugs have now been ironed out and it is quicker to draw a model in Tas than any of the others.

    In terms of catch-most it has to be Revit for me. Now if they were to release a Building Services version similar to their Engineering version- that would be catch-all.
  4.  
    Posted By: ali.gilland hot3000 for accuracy of design representation (if the commercial use licence agreement is amenable).


    The esp-r core is under the GPL so there are no restrictions for commercial use other than if derivatives are made of the core they must also be released under the same GPL provision. As for the hot3000 front-end, I'm not sure so I emailed Natural Resources Canada to find out what, if any, are the commercial restrictions on using hot3000. I suspect there aren't any but thought it better to ask. Canadian climate files for "raw" esp-r can be downloaded here: http://www.sbc.nrcan.gc.ca/software_and_tools/hot3000_overview_e.asp

    Paul in Montreal.
    •  
      CommentAuthorfostertom
    • CommentTimeAug 20th 2008 edited
     
    Posted By: ali.gillhot3000 for accuracy of design representation
    How do you mean? - Hot3000's front end invites more intricate modelling? Does that make it more accurate, when Mike's telling us that a well-judged much simplified Tas model is more than adequate?
    •  
      CommentAuthorali.gill
    • CommentTimeAug 21st 2008
     
    i see what you're saying tom, i'll edit that above.
    my point was that if you're 'not' producing epc's at level 5 then does a self employed person really need to pay £4,500 for the Tas software licence to access decent thermal modelling software?
    in which case you have the option of free offerings, being 'cut-down' versions or the possibility of a free to use licence for commercial use of hot3000, (awaiting update from Paul).
    i was following on from my post a few days before about cost being intrinsic to the equation when considering "whats the best...." and also considering the element of double handling the modelling process in tas due to the restrictive import, resulting in two working models: one for design rep and one for thermal calcs.
    also i think there was a post further back regarding the esp-r engine being more accurate than that used for tas and ies.
    •  
      CommentAuthordjh
    • CommentTimeAug 21st 2008 edited
     
    Posted By: Paul in Montreal
    The esp-r core is under the GPL so there are no restrictions for commercial use other than if derivatives are made of the core they must also be released under the same GPL provision. As for the hot3000 front-end, I'm not sure so I emailed Natural Resources Canada to find out what, if any, are the commercial restrictions on using hot3000.

    The ESP-r GPL is a red herring. I believe there is a specific licence agreement between the authors of ESP-r and the licensor (see below) of Hot3000. Just because somebody makes their software available to all and sundry under the terms of the GPL (V2 or later in the case of ESP-r) does not preclude them from granting other licences to specific people. That is what I believe happened here.

    I can't find any information about the HOT3000 licence on its site, but when you try to install it, it requires you to agree to a licence - "HOT2000 [sic] .. LICENCE .. you .. and .. THE QUEEN". The licence is *NOT* the GPL, indeed it is not even an open-source licence, since it requires you not to reverse-engineer it etc. But it doesn't appear to place restrctions on its use for commercial purposes. Obviously, the licence also appears to be for a different piece of software! The licensor is also well-known to possess a sharp sword if you should offend her.

    Perhaps the recent confirmation in the US of the rights of authors under the Artistic License will make the lawyers pay more attention. Until then, I'd download and use ESP-r but I won't install HOT3000. But for my purposes, I think PHPP makes more sense anyway :)

    Cheers, Dave
    •  
      CommentAuthorfostertom
    • CommentTimeAug 30th 2008
     
    Latest edition of AECMag eagerly awaited but not a dickybird about Bentley (Microstation)'s acquisition of EDSL (Tas) - not even the original press release - but much trumpeting, full page ad, from IES. Amazing how in less than a year thermal modelling has gone from nothing to mainstream in the CAD world.
    •  
      CommentAuthorfostertom
    • CommentTimeSep 2nd 2008 edited
     
    In fact looking around the new consolidated Bentley portal http://communities.bentley.com/there's no mention there either - not even the original press release - which, come to think, was actually a Reuters article http://www.reuters.com/article/pressRelease/idUS149469+30-Jun-2008+BW20080630 . Looks like someone jumped the gun and it's still officially under wraps. Except the article starts: "Bentley Systems, Incorporated today announced an agreement with Environmental Design Solutions Limited (EDSL) ..." - sounds official. Anyone got news?
    •  
      CommentAuthorfostertom
    • CommentTimeSep 2nd 2008
     
    IES Launches Plug-in for Google SketchUp: http://www10.aeccafe.com/nbc/articles/view_article.php?section=CorpNews&articleid=580337
    and while you're at it, free renderer for SketchUp: http://www.IDX-design.com
    •  
      CommentAuthorali.gill
    • CommentTimeOct 2nd 2008
     
    Re: Sketchup - There we are Tom, my uncanny ability to predict the future has come good again. Now i just need to get over the hangover of a hedonistic September - > Budapest; the architecture, the women, the whiskey, ooh my head still hurts.
    •  
      CommentAuthorfostertom
    • CommentTimeOct 2nd 2008
     
    What/where did you predict?
    •  
      CommentAuthorfostertom
    • CommentTimeOct 12th 2008 edited
     
    Bentley constantly announce who they've just swallowed or chummed up with, and they published their Hevacomp buy that way, but have never announced the EDSL Tas tie-up - wonder why? However there they both are now, as Bentley products: http://www.bentley.com/en-US/Products/Bentley+Tas/, with interesting stuff to click on to. Also interestingly, a vestigal discussion about it is just beginning on the Bentley forum: http://communities.bentley.com/forums/thread/14108.aspx .
    •  
      CommentAuthorfostertom
    • CommentTimeOct 15th 2008
     
    Didn't see this before:

    17 Sept 08
    Bentley Launches Building Performance Group
    New Group Will Focus on Immediate Need to Create and Maintain Energy-Efficient, Environmentally Friendly, Safer Buildings
    http://www.bentley.com/en-US/Corporate/News/Quarter+3/Building+Performance+Group.htm
    •  
      CommentAuthorfostertom
    • CommentTimeOct 22nd 2008
     
    Stunning simulations of what Ecotect can do, standalone or allied to Autodesk products: http://www.nottingham.ac.uk/sbe/creative_energy_homes/stoneguardC60/analysis_animate.html - and Ecotect isn't even a true dynamic FEA modeller like Bentley (EDSL) Tas http://www.bentley.com/en-US/Products/Bentley+Tas/ or Bentley Hevacomp simulator http://www.bentley.com/en-US/Products/Hevacomp+Dynamic+Simulation/

    I'm looking forward to this and more, seamlessly in Bentley products, and hope it happens soon enough to catch this wave, which has already been going strong for a year.
    •  
      CommentAuthorfostertom
    • CommentTimeOct 29th 2008 edited
     
    Thermal modelling goes mainstream: http://www.aecmag.com/index.php?option=com_content&task=view&id=257
    A somewhat cut down FREE version of EIS is now available not only for Revit, but now Sketchup Free!

    Every 'design your dream house' amateur will now be getting hands-on experience of fundamental and detailed energy efficiency factors, and as such may well find themselves better informed than any professionals they may turn to.

    Brilliant!
    •  
      CommentAuthorali.gill
    • CommentTimeNov 4th 2008
     
    Did you see the link to the Bentley 'unveiling' event Tom - Theres a live broadcast 6.30 pm on thursday 6th Nov.
    http://www.bentley.com/en-US/Corporate/Events/Seminars/Launch/Launch.htm?skid=CEO_PHL_LAUNCH_AEC
    •  
      CommentAuthorfostertom
    • CommentTimeNov 5th 2008
     
    Thanks Alistair, I'll watch that - this is for the launch of the new Microstation version, the bees knees yes but not at this stage incorporating any thermal modeling - that's still to come.
    •  
      CommentAuthorfostertom
    • CommentTimeNov 7th 2008 edited
     
    Thought I'd copy this from http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2868&page=1#Item_23 to here:
    Posted By: Paul in MontrealI'm not sure what the granularity of the simulation is
    Posted By: fostertomTDo you mean of Hot3000 as a whole? - I'd have thought that any true dynamic (FEA) modeller would use much shorter time steps, like a minute or something? I seem to remember being told (was it you Paul?) that a dynamic modeller like Hot3000 can be regarded as a 'bin based' calculator like Hot2000 that has short time steps?
    Posted By: Paul in MontrealActually it's the bin-based modellers that user a relatively coarse granularity (to speed up simulation). hot2000 is bin-based whereas esp-r (and hence hot3000) are truly dynamic. Though there will still be some kind of timestep, I just don't know what it is. I'd imagine hourly data would work well - rates of change of temperature are rarely more than 1-2C per hour.
    Posted By: fostertomJust to get it clear - you're talking about Hot3000 here?
    Mike George, wd you agree? - apx hour timesteps in Tas?
    Posted By: Mike GeorgeResults are hourly, but not sure if the simulation is hourly or lesser increments
    Posted By: fostertom
    Posted By: Paul in MontrealI'm not sure what the granularity of the (Hot3000?) simulation is
    Posted By: Mike Georgenot sure if the (Tas) simulation is hourly or lesser increments
    Wd be gd to know - can it be varied at will? I guess it's a bit like graphics or CAD programs - Autocad is full of legacy settings whereby you can coarsen all sorts of things to make the program run faster on yesterday's computers, but on my 3yr old fast (then) machine it flies just fine with all settings set to finest. So subject to computing power, these dynamic modellers should approach reality closer, the finer the 'granularity' (shorter the time steps - e.g. 1min or less, is my guess).
    Posted By: Paul in Montrealrates of change of temperature are rarely more than 1-2C per hour
    seems to me to offer ample scope for cumulative errors, with 1 hour time steps. Anyone know?
    Posted By: Paul in Montreal
    Posted By: fostertomseems to me to offer ample scope for cumulative errors, with 1 hour time steps. Anyone know?


    I don't think so. As I've mentioned many times, my hot2000 models are within 5% of measured reality over 3 years. The models all make approximations, but they have been qualified against test buildings over periods of several years so that those approximations are good enough to be close to reality. Changing the timestep to something smaller may allow more interesting calculations to be done (and I've read papers about modelling thermostat set-backs) but probably don't change the overall picture on an annualized basis.
    Posted By: fostertom
    Paul, this perhaps where the notion that a bin-based calculator (e.g. Hot2000) is just a dynamic (FEA) modeller (like Hot3000) running with big time steps (or vice versa) breaks down. In fact it may be misleading to think of time steps at all with a bin based calculator because that's not really how they work?

    As I understand it, a bin based calculator is just a spreadsheet of factors that have been tweaked empirically to give output that corresponds to reality, over a range of variables. The algorithms don't necessarily attempt to model physics processes, instead shortcut straight from 'if this' to 'then that'. As such, a bin based calculator is only as good as the tricks that it's been pre-programmed to do. So what starts as a quick-and-dirty way of extrapolating useful results from a resource-bank of empirical observations, becomes increasingly onerous to maintain and extend with reliability, as additional tasks are required of it.

    That's quite different from a dynamic (FEA - Finite Element Analysis) modeller, which is only as good as its algorithms which model the interactions of variables within various laws of physics. There's no shortcutting - every physical/thermal change is modelled from scratch according to laws of physics. As such, a FEA modeller can model 'anything' that it has physics-law algorithms for, although novel tasks may bring into play unexpected physics processes which the modeller may not have algorithms for, hence give false results.

    The result of an integral calculus calculation can be approximated by less sophisticated means, by dividing the timeline into a large number of slices of small duration, and calculating each in sequence, taking the output of the previous slice as the input of the next slice. That's what a FEA modeller does. However, it's only an approximation to the true result which integral calculus gives, in which the time slices become an infinite number of zero duration, so the output changes seamlessly and continuously along the timeline.

    Thus a FEA modeller isn't the ultimate, that an 'integral calculus' modeller would be, but that's into super-computer territory. A FEA modeller's virtue is that it will run on ordinary computers. However, such time slicing can give big cumulative errors, the fewer/bigger the slices get, so FEA is a balance between speed (i.e. minimised no of iterations, afforded by small no of big timeline slices), and accuracy (i.e. lots of iterations, necessitated by large no of small timeline slices).

    If a FEA program doesn't have a way for the user to choose that balance, according to the task in hand and the accuracy required, then it should have! - unless it's intelligent enough to vary and make that choice automatically.
    •  
      CommentAuthorfostertom
    • CommentTimeNov 7th 2008
     
    I've seen reference to 'computational fluids dynamics' CFD software - could this be pukka fully-continuous modelling of fluids (incl thermal? incl solids?) requiring big computing power, as distinct from FEA timeslice modelling of ditto requiring only desktop computer?
  5.  
    Now my comments have made the printed world (thanks by the way whoever helped out on that), I thought I'd better get back to being involved in this forum.

    TAS has an hourly simulation timestep. Heat transfer through the fabric of the building is dealt with by a response factor approach (ASHRAE methodology) and the overall heat balance is gained by basically solving a set of simultaneous energy equations for the surface and air temperatures, etc at the same time. Just a note from above, TAS Bentley tie up is what I would consider an alliance, as TAS remain an independant company at this time as far as I know. This is, unlike Hevacomp which was a full acquisition, much like Autodesks purchase of Ecotect and Green Building Studio.

    IES on the other hand uses a finite difference methodology. With this simulation engine, you can choose the simulation timesteps and reduce them down to 1 minute which is particularly useful if you have instability in the solution, which can sometimes occur with some very buoyancy driven flows.

    Finite element analysis is generally used for modelling things like cold bridging and condensation. We use a program called Therm. It's a freely available tool from LBNL and is great for looking at things like condensation possibilities on window details and things lke that. FEA can be either Steady State or Transient, but tends only to be used on little portions of the building or its component parts. It essentially calculates the surface and interstitial temperatures throughout each material of the whole component based on a set of boundary conditions. For example if you have a low external temp and you model an exposed concrete beam it will show you the flow path for energy loss and may be used to calculate where the surface temperature drops below the internal dewpoint temperature and hence where condensation will occur.

    Finite Volume Analysis (CFD included) is where the domain is split up into discrete volumes of air then the energy and flow equations along with turbulence algorithms normally are iteratively solved to give either a steady state solution for looking at what is happening in a flow domain (space, whatever it is) for that particular moment in time according to the boundary conditions applied to it. Transient analysis varies one or maybe more of these boundary conditions. This is really serious modelling that will take vast computing power and for buildings is probably unnecessary unless you are doing fire and smoke analysis or something like that.

    TAS, IES and DesignBuilder all have CFD modules. I think out of these DesignBuilders is currently the one that I'd favour although IES's at this exact moment in time is the only one that migrates boundary conditions from its dynamic simulations to its CFD module which takes the guess work out of boundary condition definition. I know DesignBuilders CFD will be able to do this very shortly too. Hevacomp had a link to CHAM Pheonics which is a fully featured CFD engine that can do analysis of all sorts of things. I suspect that's where the reference comes in. A parred down version was available to existing Hevacomp users for an additional £500 pre-acquisition. Not sure about that now. If you want to do serious CFD that will be the way to go as it can mulitspecies flow unlike the others as it is a full CFD engine like Fluent, StarCD, etc.

    Not sure if this helps or muddies the waters even more.
    Cheers for now
    Paul
  6.  
    By the way Bristolpaul = PaulZED - not sure what I've done there.
  7.  
    Anyone used this? Courtesy of Tom Foster http://canmetenergy-canmetenergie.nrcan-rncan.gc.ca/eng/software_tools/basecalc.html

    How close is it to DSM?
  8.  
    Also take a look at Watsun 2008:

    "WATSUN 2008 is a program that models the performance of commercial and residential solar water heating systems including those with or without thermal storage. The simulation normally uses hourly time steps but smaller steps may be used when the controller turns the system on or off. The storage tank may be modelled as mixed or stratified and the load may be defined in considerable detail. The program predicts the total energy used by the load, the solar energy collected, the fraction of the load met by solar and several related energy quantities."

    http://canmetenergy-canmetenergie.nrcan-rncan.gc.ca/eng/software_tools/watsun.html

    Paul in Montreal.
  9.  
    Finally had an answer about the terms of use for hot2000 and hot3000:


    HOT2000 (the General release) is free to use for fun and/or profit. Of course the results you obtain are dependant on the data you provide, and are subject to the limitations outlined at the bottom of the Full Report. Also, HOT2000 is intended for use with "small" residential buildings.

    The same conditions will apply to HOT3000.


    Paul in Montreal.
    •  
      CommentAuthorfostertom
    • CommentTimeFeb 11th 2009
     
    • CommentAuthorralphd
    • CommentTimeFeb 11th 2009
     
    Posted By: fostertomAnother treasure trove of modelling software, thanks to ralphd inhttp://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=3554" >http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=3554:http://windows.lbl.gov/Default.htm" >http://windows.lbl.gov/Default.htm


    And thanks to djh earlier in the thread, I checked out PHPP. A quick 5-minute scan of the excel sheet data has my brain hurting.
    http://www.passive-on.org/CD/?path=./4.%20PHPP%202007%20Demo/

    -Ralph
   
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