How to calculate the heat loss of this building

[ankofl]

I gave an example of a building whose enclosing structures are made of different elements that overlap each other in projection. As with Revit or settings from Autodesk.AppStore is it possible to calculate heat loss through the walls of a given building, given its entire multi-layered structure?

Square - columns
Thin wall - insulation
Thick wall - brick

Zones Celsius:
orange +25
green +10
blue -20

p.s. the main problem in this case lies in the columns, because they cannot be included in the structure of the walls, as in those cases where there are exactly two walls next to each other (thin insulation and thick brick)

[iainsavage]

Depending upon your Revit version you can use either the Heating & Cooling Loads calculation tool or the Systems Analysis tool.

You should first read the help topics and some of the other posts on this forum regarding those topics to ensure that you set your model up correctly for analysis otherwise you will get strange results.

[ankofl]

The problem is that the toolkit available from the Revit API for creating an "Analytical model of a building" creates very curved "Analytical surfaces", while with the same settings, the tool "Calculation of refrigeration and heating loads" creates correct surfaces, but does not have access from the API, and also does not save calculated "correct" surfaces in the model after the window is closed. Relevant for Revit2024

[iainsavage]

You asked "is it possible to calculate heat loss through the walls of a given building".

I pointed you towards the tools which Revit provides for that purpose.

I have no idea what the API does, I've only used the tools, never drilled down into the programming behind them.

Maybe someone more technical can advise you such as @Kevin.Lawson.PE

[ankofl]

@iainsavage I'm sorry if my answer seemed rude, I didn't mean it. I wanted to say that "Analytical spaces" and their "Analytical surfaces" - absolutely useless, but they are stored in the model, and you can use them to make a specification, perform some further calculations using standard Revit tools.

While the "Refrigeration and Heating Loads" tool, for some unknown reason, creates the same "Analytical Spaces" and their "Analytical Surfaces", but already correct, but at the same time it does not save them in any way in the model, but only allows you to save a tabular report in the project, which also it is absolutely useless for the following reasons:
1. the parameters of his calculations are incredibly difficult to adjust for a specific room (there is no simple way to specify a specific number of people in the room, a list of equipment and its thermal output, and much more). With such a long manual setup, it makes no sense to have all the data present in the model, because with such time spent on setting up elementary parameters that could fit into a dozen parameters of "Space", it will be faster to perform even a calculation on paper, or even more in Excell
2. There is no way to customize the format of the report to the national standards adopted in the examination, which means that the entire report (even if the data in it were correct, which is not the case) would have to spend several hours each time the building was recalculated to reissue the document to the type of national standard.
3. It is not possible to verify the correctness of the enclosing structures and their analysis in general (how correct the structural elements were taken into account, and whether they were taken into account in principle, and so on)

In general, from one year of working with Revit exclusively as a power supply design engineer, and then two more years of experience writing programs for Revit, I can say with confidence that with very few exceptions, for the correct operation of almost any Revit function, it requires writing at least a small, but still your own program

[iainsavage · Accepted solution]

There are a few other previous posts which discuss the shortcomings of Revit's load and energy calculations.

Might be worth searching them out.

Also Revit uses the EnergyPlus programme by OpenStudio so its maybe worth going on to their website and reading some of the native documentation which might be more informative than ADSK's versions.

EP does however rely on Revit to send it the correct input data and also Revit may not then return all of the available data from EP into the Revit reports so that may be where inaccuracies or deficiencies occur - that's just my opinion but I've never looked too deeply into it to verify that.

You also have the option of exporting the model to gbxml format and importing it into native EP or another analysis programme and there are also "seamless" plug-ins available for analysis software such as IESVE.

The Heating & Cooling Load tool is a bit archaic and I don't know if its ever been updated by ADSK since 2007 - I'm not actually sure if it even uses up to date versions of EP, I think it maybe uses an older archived version?

The tool has however been all but discontinued - they deleted from the 2021 version of Revit but due to some pressure from some users they brought it back secretly and it will only appear on your ribbon if you have edited the Revit.ini file to expose the hidden tool.

For that reason I would use it with a lot of caution.

I've not really examined the Systems Analysis tool because by the time that I got it working (I was affected by the incompatible processor problem) I had decided to retire so I've only looked superficially.

@Kevin.Lawson.PE is probably the best source for more details and his company Ripple Engineering have developed and made available some addons which might be of interest to you.

I think several of your comments are not completely accurate but I think if you read other posts you'll see that you are not the first person to raise concerns regarding the reliability of Revit's tools.

Good luck in the future and I hope that you find a method which works for you.

[ankofl]

I believe @iainsavage have provided me with the most comprehensive answer! Thank you so much for it! Special thanks for the third-party programs you recommended, after a cursory review of them, I discovered a large amount of new and interesting information