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Christiaan

Energy efficiency analysis and VectorWorks

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With the new Code for Sustainable Homes coming online this year in the UK, building energy efficiency analysis is suddenly going to become standard procedure in the UK AEC industry (as it is already in many parts of the world).

There's a group at BRE working on some software with regard to the above but what are the options out there being used already? Are there any tools that integrate well with VectorWorks? And what sort of influence is IFC going to be on this area?

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For those in the USA, the US Department of Energy has the free and very useful "ResCheck" program that can be used to check compliance with energy codes in many different areas. After inputing the required information, you can print a report that is filed with the permit application when required by the local jurisdiction.

As far as I know, there is no integration with any cad program, but such integration is probably impractical given the ever changing and unique code requirements of many different areas.

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such integration is probably impractical given the ever changing and unique code requirements of many different areas.

Except that energy efficiency isn't quantified by code requirements, but scientific measurement, so there could be quite a degree of integration before you then need to plug the figures into something that will tell you if you complying with any given code or not.

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Further to the above, as I understand it, IFC will actually create a common framework that will allow for a degree of integration. Or at the very least we're going to end up with a common file type that energy analysis programs will be able to take from VectorWorks (when it's IFC compliant). So it would just be a matter of ensuring that you tag your model correctly (such as tagging your walls with the correct thermal resistance, etc.).

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I just read that the merger between Nemetscheck and Graphicsoft is complete, or at least there was a press release today.

I think it would be of great value for VectorWorks to integrate some sort of capacity to model building energy consumption over time. Of all of the "green" building materials available, how does a person really know how the myriad choices of materials that create a so called efficient building truely affect the "ecological footprint" of the building? I'm using the term "ecological footprint" to mean the resource consumption to construct and that is inherent over the lifecycle of the building.

In the US we use LEED, (leadership in energy and environmental design) as a checklist for increased energy-efficiency in buildings and now neighborhoods, (LEED - ND). I am currently working on a project that will be submitted for LEED for Buildings, and LEED - ND approval, and so have done some research on the subject of energy modeling. Although I did not find much, I found an interesting person by the name of Georg Reinberg who I plan to research more indepth. He was part of the Austrian effort in sustainable design that brought them further ahead in the subject then most of the world. He is currently in the Building Sciences Department at Virginia Tech and may be a good contact on the subject.

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I think we are seeing real progess here, as comes to the technical capabilites of VW.

At present it is already possible to quantify wall materials. Not easy, not a built-in function, but doable. R-values of walls can be recorded and reported; apart from some strange glitches (bugs), energy loss through walls can be calculated.

With floors and roofs the situation is a lot worse, but there are methods already.

With doors and windows, the situation is even worse, unless one has access to better door & window objects than NNA provides. The better ones include home-brewed symbols with appropriate data attached.

What is totally missing is the ability to calculate the effects of solar radiation: "If we have eaves like this, what's the annual energy balance through windows like that, in our geographic location?"

Tough questions. The winner takes it all: this will be the Next Big Thing. Surely we don't want Mr Engineer to control it?

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I went to a seminar, called Aiming for Zero Carbon, at this year's Ecobuild in London, where RETScreen was highly recommended. The BRE could learn a thing or two about producing software from these guys (especially price wise).

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And make sure that if you are doing all this "EXTRA" learning

that you get Extra pay for all your efforts.

If you think that you will be doing it all at the same old rates just tell your clients that you will need an engineer to get all those calculations done then add a processing fee to get the engineer and you win.

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VWA has been "supporting" energy analysis since version 9, with the Export DOE-2 feature. This exports the floor, wall, window, door, and roof geometry in the drawing to a text file in a format used by energy simulation calculators such as EnergyPlus. So while VWA does not do the analysis itself, it can export its information to a program that can, saving the effort of re-keying all of the geometry.

If you have to do an energy analysis, contact a local energy consultant and you can probably get a faster turn-around from the consultant, and a reduced fee, by providing just the DOE-2 file instead of the drawing.

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Is that format globally known? Do energy efficiency calculation programs in every country support it?

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Petri,

That I couldn't tell you. Even in the US, there are actually a variety of calculation methods, as well as regional differences in acceptable heat gain/loss. Also, the last time I checked (several years ago), the DOE calculation engines relied on climate information that only included the US. This might no longer be true.

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The point that Petri is making is very pertinent. There is a need for an export in an international standard that those of outside of the USA can use.

A point to be mindful of though is that the accuracy of the results would be directly proportional to the accuracy of the model, and the quality of the data attached to each of the building elements.

The only program I know that can do the energy analysis direct from the model is Ecotect by Square One Research: http://ecotect.com/home A capability to export to this program would be nice. Dr Andrew Marsh also has some interesting observations on the range of issues associated with this topic on his Natural Frequency discussion page: http://naturalfrequency.com/

Edited by mike m oz

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DOE 2, developed at Lawrence Berkeley Labs at UC Berkeley, can be used anywhere in the world. All it needs is climate data, something that is fairly easily compiled. Why reinvent the wheel that a slew of PhD students already slaved over?

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DOE 2, developed at Lawrence Berkeley Labs at UC Berkeley, can be used anywhere in the world.

I'm sure it CAN, but if there are no local, certified programs supporting that format, it's useless.

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I'm sure it CAN, but if there are no local, certified programs supporting that format, it's useless.

Good point. DOE 2 creates a mathematical model of a building's energy usage, including maxmimum cooling and heating loads and a profile for energy usage in every day of the year. In other words, it generates information in univerally-accepted thermodynamic units. From this information, one just compares to the legal requirements.

All that is needed, first of all, is a standard, and then certification for DOE 2. In the US there are front-end programs that generate reports and forms demonstrating compliance according to the format of the local jurisdiction.

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Good point. DOE 2 creates a mathematical model of a building's energy usage, including maxmimum cooling and heating loads and a profile for energy usage in every day of the year. In other words, it generates information in univerally-accepted thermodynamic units. From this information, one just compares to the legal requirements.

I'm sure it does. Now, should we expect that the entire world abandons millions of person-years of research, based on local conditions and, in many cases, preceding anything done in the USA by decades, just to comply with what a couple of PhD students have put together in California, the least energy-conscious part of the world?

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Energy analysis doesn't over-ride practical knowledge, at least not in my experience. It doesn't tell you how to build something, and it doesn't even tell you what size plant your building will need -- at least not reliably enough for the contractor to go by. If the energy analysis predicts the size of the plant that actually gets installed +/- 10% that would be unusual. It doesn't know how fast you want to accomplish temperature recovery on Monday morning, or how absolutely certain the clients want to be that the proper temperature is maintained on an extreme day. But it WILL tell you, +/- 1%, how much difference in yearly energy costs a different building material will make. In other words, any given baseline might be pretty far off, but the difference between two baselines will be pretty accurate. So if you have an energy analysis tool, you can play around with different design strategies, and get a pretty good idea of the impact that they will have on the operating costs of the building. And this is not country specific -- the laws of thermodynamics are universal. But you do need the local climate information (temperature of air, temperature of ground, depth of permafrost, number of sunny days in a year, humidity, etc.).

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Charles, I always size my equipment based on our Title 24 reports (California standard), which are generated by DOE 2 technology. Same with our mechanical engineers. All engineering is based on calculations (tempered, granted, by experience). DOE 2 is just a basic thermodynamic calculation model, and I'd like to know what software does a better job for buildings.

Petri, "DOE" stands for "Department of Energy," a national agency. Lawrence Labs is contracted by DOE to do a lot of research, including basic research in energy efficiency. It's probably the leading facility in the US, and responsible for breakthrough technology in energy-efficient lighting and the California energy standards which lead the US by at least a decade. I wouldn't thumb my nose at the expertise there. The place is crawling with theoretical physicists.

So I thought that getting VW to plug building data into DOE 2 sounded like a pretty good idea, and achievable!

By the way, I note that Finland ranks third in the world in energy use on a per capita basis, behind the US and Canada. California uses less energy per person than any state in the US, ranking dead last among the US states at about 55% of the national per capita average (which puts it well below Finland in energy usage per person). California just adopted a goal of reducing greenhouse emissions by 80% below 1990 levels by the year 2050 (by the good graces of our Austrian governor). What is Finland's goal?

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What is Finland's goal?

Not exactly sure about the figures (and their actual meaning in the real world), but reduction, reduction. Within the Kyoto agreement and EU's overall policies.

Considering that Finland is the coldest country in the world and quite sparsely populated, we use surprisingly little energy. As comes to buildings, this is because energy-efficiency has been an integral part of their design for decades.

An energy analysis has been required for all building permits since the 1970s, so somehow I believe we have all the expertise we need and do not need help from California, where the practical experience of semi-arctic climate can't be particularly high.

EDIT

My apologies. It seems Mongolia is even colder than Finland. Compared with the mean annual temperature of -2.3 ?C of Ulan Bator (whichever way you want to spell it), the +4.5?C of Helsinki and even the +0.4?C of Rovaniemi (Aalto aficionados should know about Rovaniemi) are tropical.

Obviously we are, climatewise, quite comparable with the Ashram of the Real Gurus, Berkeley (+18.0?C)...

Edited by Petri

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Petri, of course climate has a major impact on energy use. In California, though, the major energy concern with buildings (after lighting) is cooling, not heating. Alaska, which has annual temeratures comparable to Finland, also ranks quite low in the US, almost as low as CA, in per capita energy use.

I would never cast aspersions on the expertise of Finland's architects and engineers. I only meant to observe that DOE 2 seems to me to be a perfectly adequate program. Based on yours and Charles' comments, if VW is already close to being able to hook up with DOE 2 to produce a building thermodynamic model, why not take advantage of that to complete the loop in the fastest and easiest possible way?

The VW user could then, with the click of a mouse, get a reading on the relative energy-efficiency of a design (per Charles' arguments), and with a worldwide database on climate data, get actual energy usage estimates. I don't beleive that any other CAD program offers such a utility, and connecting the dots here could be a major selling point for VW - benefitting all of us who use the program in more ways than one. Thanks to Christiaan for raising the question!

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and with a worldwide database on climate data, get actual energy usage estimates. I don't beleive that any other CAD program offers such a utility, and connecting the dots here could be a major selling point for VW

Better hurry on this ... or Google will beat everyone to it ; )

Another informative post .. thanx !

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why not take advantage of that to complete the loop in the fastest and easiest possible way?

Umm? Like writing my own analysis software that would then take the industry by the storm? I'd wipe out dozens of engineering firms and software companies, take over the State Technology Research Institute and mandate that every architect and engineer uses VectorWorks from this on?

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Petri, of course climate has a major impact on energy use. In California, though, the major energy concern with buildings (after lighting) is cooling, not heating.

Fancy that. When I was in a team designing a fairly major & prestigious building to Baghdad in the late 1970s, we used pretty much the technology we were familiar with. Great success energy-wise, if I may say so.

Alaska

Here I'm totally ignorant. Is Alaska a major manufacturing area with a huge heavy industry and dozens of paper mills exporting world-wide? Not to mention exporting paper machines, world's largest cruising ships and stuff like that?

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We missed something here -- Petri, you said that in Finland,

An energy analysis has been required for all building permits since the 1970s.

Maybe we DO have something to learn from you guys. What sort of methodology is used? What are the regulations? This indeed is an international issue, with international applicability. Admittedly my research has been limited to US techniques and regulations, and my building experience has been limited to the East Coast. If you could point me to some online resources for Finnish energy analysis, I'm interested.

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