PHBdW: Passivhaus Bau der Woche 04.5

This week’s PHBdW features a passivhaus warehouse of sorts, by Architects Collective. The Obst-bau Leeb is located in Sankt Andrä am on Zicksee, along the easternmost Bundesland of Austria. It is an apple processing and storage facility with an attached sales and administration building, the latter being the passivhaus element of the project.  

The clients were motivated to make the building as green as possible, utilizing recycled or re-used materials for interior lighting and casework, and lower-embodied energy materials to minimize the facility’s footprint. The building utilizes prefabricated wood panels that were installed in a few weeks. Total construction took less than six months.

The prefabricated panels are somewhat similar to SIPs, with OSB on the interior (presumably the air barrier), 16” TJIs with cellulose insulation and a fiberboard exterior. A rear ventilated OSB rain screen uses different stains to add a touch of frivolity to the hyper minimal facade. The roof is constructed of the same panels, and a suspended ceiling (thankfully, not ACT) allows for recessed lighting that doesn’t penetrate the air barrier. This is critical in achieving the passivhaus airtightness requirements.

The floor is a 4″ concrete slab over 10” of insulation. We still struggle with these amounts of foam insulation, but after completing the Passivhaus Consultant training and tooling around with PHPP, understand the reasoning behind it.

Ventilation is supplied through a Drexel und Weiss aerosmart mono, a highly efficient compact HRV with heat pump for space heating. Large operable screens finished with adverts provide shading from excessive solar gain in summer. We’re also really impressed with the large lift-slide doors – any thoughts as to who manufacturs a passivhaus certified hebe-schiebetuer?

  • Walls: U-value=0.10 W/m²K (R-57)
  • Roof: U-value=0.10 W/m²K (R-57)
  • Floor (slab): U-value=0.11 W/m²K (R-51)
  • Windows: U-value=0.75 W/m²K (R-7.5), SHGC (G-wert) =0.52
  • Airtightness: 0.26 ACH50 (this is ridiculously tight)
  • Heating Demand: 16.1W/m²K/a (5.10kBTU/ft²/a)

This small project is a success on many levels. It’s definitely inspiring to see a firm pushing the aesthetics and energy efficiency of a simple industrial facility. We are looking forward to architects and clients on this side pushing the highly efficient, well designed envelope as well.

Further Reading

  • archinect write up with several additional photos
  • Nextoom.at writeup (German)
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5 responses to “PHBdW: Passivhaus Bau der Woche 04.5

  1. namhenderson

    Is the fiberboard exterior than finished with resin/or some sort of weatherproofing, I assume?

    As for high amounts of insulation do you “struggle” with it because it is so much outside of the norm of US projects? My understanding is that the insulation factor and lack of breathability (airtightness) are two of the major ideas which drive Passivhaus designation. True or not?

  2. nam,

    the fiberboard exterior has a ventilated rainscreen w/ a stained OSB finish.

    i struggle with the copious amounts of insulation because i worked on low-energy projects in germany that utilized almost zero insulation. so i tend to oscillate between the two worlds. the insulation factor isn’t a necessity for passivhaus – in fact there are a few projects with a lot of glazing (but not cheap).

    -mike

  3. nice blog, Mike!

    do you think insulation is intrinsically a bad thing, then?

    how would you create comfort without insulation at all, especially say for a smaller building where the heat being generated internally is minimal…?

  4. will,

    likewise, i imagine it’s even harder for you to keep the frontoffice blog going. but keep it up, it’s great to drop in and see progress!

    i don’t think insulation is intrinsically bad… certain kinds are (XPS, closed cell) – see alex wilson’s recent environmental building news article for a quick summary.

    and it’s not that cellulose or fiberglass are good (though definitely much better) – but if you can utilize thermal mass, process energy, etc to make a functional, comfortable building without insulation, i think that is amazing. and there are folks doing it, and the work tends to be pretty phenomenal.

    i think the question about how to create comfort in smaller building is a good one. it’s especially challenging to meet passivhaus with small projects – and comfort can be relative. you don’t need much if any insulation in san diego to be comfortable in winter. anchorage or siberia would be another story. although with a passivhaus, your heating needs are so minimal that internal heat gains and a little solar gain may be more than enough to keep a house warm.

    as for how i personally would create comfort? adequate insulation, airtightness and a rocking solar thermal collector charging a superinsulated thermal storage tank for all my heating demands (via radiant floors). and if i’m lucky, domestic hot water as well.

  5. thanks for response. it is intriguing. would love to try some of this out someday in a project.