BauSIM 2020 Roundtable Discussion — part 2
BauSIM 2020 Roundtable Discussion There is greater public and political awareness of accelerating global change now than ever — not least because of the imminence of COP26, which starts at the end of this month — and still much to do in order to tackle the challenges this poses for building simulation: more so when we consider the time-horizon in the context of a predominantly static building stock. With this in mind, BauSIM 2020 included a roundtable discussion with leading experts in the field of building performance simulation on the topic of “challenges and future endeavors”. Participants for this discussion were Professor Joe Clarke (Professor Emeritus, University of Strathclyde, FIBPSA), Professor John Grunewald (Professor and Chair of Building Physics, TU Dresden), Dr Per Sahlin (CEO EQUA Simulation AB, FIBPSA), Dr Michael Wetter (Deputy Leader Simulation Research Group, Lawrence Berkeley National Laboratory (LBNL), FIBPSA), and Andrew Corney (Product Manager at Trimble - SketchUp and Sefaira, UK; FIBPSA). This article is a second extract from the discussion. The first was published in the previous newsletter, April 2021. Each of the participants was asked to provide a short statement in advance of the discussion, and Christina Hopfe (TU Graz, FIBPSA), the moderator, used these as the basis for the questions which she put to the panel. The second part of the discussion started by considering Per Sahlin’s statement:
“
We need to collectively promote the advantages of a model-based design process, where design decisions are made by experiments on the current state of an evolving holistic dynamical model. Mandatory requirements of monthly calculation methods must be phased out, as must silo model building to fulfil the requirements of a specific standard
”
(Per Sahlin)
Christina Hopfe (Christina): Per, what evidence is there actually that more sophisticated,
dynamic tools or techniques actually result in better buildings? Surely the folks of the Passive House Institute in Germany would argue that their simple spreadsheet model results in better buildings than many designed using very sophisticated tools. So, who actually benefits from the added complexity? Per Sahlin (Per): I think the Passive House approach is interesting because it puts things on the
spot. I think it’s exactly those sorts of buildings, with large glazed areas and very well insulated - very far from the sort of 60s and 70s types of constructions - that prove that you really need dynamical methods, because overheating is very difficult to look at in a monthly context. And I just don’t understand how you can avoid overheating problems in such buildings. There are plenty of examples that I’ve seen where people buy an apartment for a huge amount of money and then in the summer it’s 60 degrees centigrade in there; it would have been super simple to spot this problem had it been simulated before. These things still happen quite often. I don’t think we need to convince ourselves in this group whether or not that simulation is meaningful, or to debate the merits of monthly methods. But in the marketplace it’s a reality, especially in the DACH countries (Germany, Austria, Switzerland) - especially in Germany I would say; since there’s a mandatory requirement to perform a monthly energy study for every building that you put up, it’s
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volume 31 number 2
