Passive Building Standards–What about Embodied Energy/Carbon?

GWPHIUS Senior Scientist Graham Wright is back this week, this time following up on a comment made to his One Cereal Aisle, Many Cereals post from last week. Reader Sarah Larsen (thanks Sarah!) asked about embodied carbon issues. The answer, we thought, deserved its own post, and we hope, discussion.

First, here’s Sarah’s comment:

Graham, thank you for such a thorough and thoughtful post. As a licensed architect, and CPHC I am already inclined toward the PHIUS methods, but continue to be curious about the nerdy differences, how, and why they came to be. I am also incredibly happy with the relationships being developed between PHIUS and code/regulatory agencies; it is critical that energy-efficient building practices spread beyond the geeky few.

The graph shows per capita energy consumption (kg oil equivalent) vs. per capita GDP, PPP (current international $). The size of the bubbles denotes total poulation per country. All values refer to the year 2011. Courtesy European Environment Agency.

The graph shows per capita energy consumption (kg oil equivalent) vs. per capita GDP, PPP (current international $). The size of the bubbles denotes total population per country. Click to enlarge. Data from the Eureopean Environment Agency and the World Bank.

With that said where is the EMBODIED CARBON calculation in our standards?? I can’t stress enough how important it is that we take this into consideration. There are PHIUS certified buildings being developed touting their energy and sustainable credentials who are using products with CO2e paybacks that will almost certainly never be met. We have just 10 years to get this right – a 90 year ROI is not going to cut it! I am very much afraid that if we develop code requirements with blinders on to anything but energy *consumption* we will have the reverse impact that we are working toward – climate catastrophe – by packing our buildings full of foam rather than thoughtfully balancing carbon footprint throughout a life-cycle assessment (LCA).

LCA has some growing up to do, but tools such as Tally are already making better, more broad-thinking choices available to anyone who cares. It is critical that leaders such as PHIUS be talking about embodied carbon and the up-front resource demands of our built environment. I think we could adapt Michael Pollan’s advice on eating as the best way to consume other resources: Build efficiently; not too much; use mostly plants.-– yours in climate-conscious building – Sarah Larsen

Now, back to Graham:

We are aware of the issue but feel we are not yet to the point where we can outright standardize, that is, make hard and fast rules. The Norwegian Institute for Zero Emission Buildings came up with some different definitions depending on how many building life cycle phases are included.

We can move more aggressively to put up some resources and guidelines. There are a couple of books I have found that seem to be helpful for making design decisions:

Most of the thinking I have seen focuses on materials, but I am not convinced that is a broad enough view of it. Suppose one uses low embodied carbon materials but this requires a lot of expensive skilled labor. The money paid for that fans out into the general fossil-powered economy, which has a certain emissions intensity per dollar, so there are emissions associated with all that economic activity, so maybe you don’t come out ahead.

From that point of view, low-cost construction is low-emission construction, and everyone is trying to do that already. I remember back in 2013 or so, the IEA or the EIA put up an interactive data browser that let you see what they were thinking in terms of scenarios to limit warming to 2 degrees C. It was clear that they were not counting on much of a contribution from the building sector. It’s pretty clear that the reason for this is that the turnover of the building stock is too slow, there just isn’t enough time anymore.

As I recall in their 2 C scenario for the U.S., almost half the total savings came from decarbonizing the generation of electricity. The “electrify everything” movement has strengthened since, Architecture 2030 seems to be on board with that, recognizing that anything done in new construction standards doesn’t do anything about the existing buildings, which is most of the problem within that next-ten-years window — so the priority is to stop emissions from existing buildings by electrifying. This is part of the reason we modified the overall energy criterion for PHIUS+ 2018 — it allows for off-site renewables now and that is compatible with the “electrify everything” idea. Some people, like ILFI, go even further and just ban all combustion from building operations.

But back to the embodied emissions. Here is an idea I had about how that might be written into a rule. Let’s call it PHIUS+ Equity & Carbon 😀

It would address both equity and embodied energy/emissions with adjustment to the Source energy limit based on construction budget, on the idea I mentioned above, that embodied energies/emissions are roughly indicated by how much money is being spent, along with the emissions intensity of the national economy.

The adjustment would be based on the idea of limiting the total operating + embodied, so, operating + embodied < 714+221 = 935 kWh/sf for example.

To generalize:

SE * 70 yr + $CB * NatkWh / NatGDP < 10.2 kWh/sf.yr * 70 yr + $170/sf * NatkWh / NatGDP

where

SE = modeled net source energy for the project [kWh/sf.yr]   — about 10.2 kWh/sf.yr
$CB = project construction budget [$/sf]   — about $170 /sf, U.S.
NatkWh = National source energy use [kWh]  — about 29 trillion kWh, U.S.

NatGDP = National gross domestic product [$]   — about 19 trillion USD

This is mathematically equivalent to adding a penalty for high-budget construction and a credit for low-budget construction, which is in the equitable direction, on a world wide basis even. The emissions intensity of the Indonesian economy is actually higher than the U.S., I make it out to be 0.44 kgCO2e / USD, while the U.S. is 0.29 kgCO2e/USD. But they catch a break with the above scheme because their cost of construction is a lot lower, about $60/sf instead of $170 for the U.S., so multiply those two numbers together and the Indonesian building industry is putting out 0.44×60 = 26 kgCO2e/sf while the U.S. building industry puts out 0.29×170 = 49 kg/sf.

I switched to carbon accounting for a minute there, but I still prefer source energy accounting. It’s a pretty good proxy for emissions because 80% of the primary energy is coming from fossil fuel burning, but I like that source energy penalizes nuclear for being nonrenewable, whereas straight carbon accounting gives it almost a free pass.

Solving the above equation for Source Energy criterion:

SE < 10.2 kWh/sf + [($170/sf – $CB) / 70 yr] * NatkWh / NatGDP

This would also tend to do a favor for retrofit projects if they are able to save construction cost by reusing the structure — and that is the high-embodied-emission part, for concrete and steel buildings, from a materials point of view. The $170/sf could be generalized to a national average value as well, $NatCB. For residential projects, just substitute for the 10.2 as 3840 kWh/person * ResOcc / iCFA.

Probably only the operating-energy part of it tapers to zero in future. More emphasis can be put on initial-cost/embodied-energy savings by shortening the time frame. At 20 years instead of 70 they are about equal in the initial example. This would favor retrofits even more.

Many Cereals, One Cereal Aisle

GW

Graham Wright

The PHIUS+ standard has evolved on a very different path than the PHI standard, and they are in no way equivalent. That’s by design, based on deliberate decisions and building science, with a focus on cost-optimization and climate specificity. Still, confusion remains in some corners of the marketplace, confusion that is worsened by articles like the one that appeared in BuildingGreen a few weeks ago. (You can also read Chris McTaggart’s rebuttal at Building Green.)

Here, to provide a full accounting of how and why the standards are different, is PHIUS Senior Scientist Graham Wright. 

At the Seattle PHIUS annual conference in 2017, one of the keynote speakers, Doug Farr, came to a line in his speech saying “many boxes, one cereal.” The point he was making (as I heard it) was that there are a whole lot of “green” and “sustainable” and “high-performance” building programs, badges, and ratings all competing for attention or mind-share, and that this was not good because it made for a diffuse effort toward solving our sustainability problem. What you have, he said, is like a whole bunch of different cereal boxes on the shelf, but inside it’s “all kind of the same stuff.” It would be better if all these different outfits would get together to advocate with one voice.

While I agree that joining forces sounds like a good idea in general, personally I think he got the rest of it almost exactly backwards. For one of the other keynote speakers, Eric Werling, one of his major points was that the details matter. In terms of cereals, it is not all the same stuff — muesli is different from oatmeal or cornflakes or Cap’n Crunch®. We do not have many boxes — one cereal, rather we have many cereals, one cereal aisle. The bacon and hash browns are in another aisle. For the building industry the name of that aisle is probably “Green Building,” I think that’s the broadest and most recognizable term for what we’re talking about, and could encompass high-performance, sustainable, resilient, natural, living, green, healthy, net-zero, and of course, passive. Things it does not encompass but at most only overlaps with would be for example: secure, co-housing, modernist, Usonian, affordable, vernacular, brutalist, social, connected, low-tech and so on — these are quite different “programmatic” considerations and have their own aisles in the pan-galactic building store.

One of these things...

One of these things…

In the case of cereals the reason there are different kinds is because tastes differ, but also because values differ — if I value yumminess above all I will get Cap’n Crunch, but if I value avoiding the family curse of heart attack above all, I will get the oatmeal. In Green Building even more so, we have different programs because of differences in truly heartfelt values. Both builders and their clients bring different values to their meetings — if I am concerned about not polluting the environment, respecting brother salmon, I will go into natural building; if my children are prone to allergies I will look for healthy-home builders; if I

...is not like the other.

…is not like the other.

hate paying utility bills I will go for net-zero, and so on. So it is useful to have badges and rating systems corresponding to these different values or priorities, for matchmaking between builders and buyers of buildings.

Back to the common ground for a moment. It has dawned on many people I think that these different aspects of green building are connected, by a general crisis of climate and sustainability with industrial civilization, that we do have common ground in making the point that we must stop using fossil fuels and putting CO2 and other pollutants into the environment and doing so much mining, if we expect to also keep getting things like fish and wood and well water out of it at the same time, and that we might be able to form a chorus of voices calling for this.

I know of three such separate “common voice” efforts (heh) arising in the last couple of years:

PHIUS has joined Shift Zero, which has come together around the Architecture 2030 definition of zero net carbon buildings. Washington State already has one of the strictest state building energy codes, more stringent than IECC 2015, according to ACEEE, but at the initial Shift Zero summit meeting, the item “Roadmap to a Net Zero Building Code” was chosen as a major focus. This is relevant to us for two reasons: 1) We believe passive building should be on that road! The PHIUS vision statement is to “make high-performance passive building commonplace,” which it would be if it was Screen Shot 2019-08-27 at 1.46.00 PMcode. Also, 2) although it’s not spelled out in the short mission statement on the web site, the long version in the business plan speaks of the climate crisis and how passive building can both mitigate and adapt to climate change. We concur that as a society overall we must get to Zero, not just net-zero but Absolute Zero in terms of emissions, or 100% renewable energy to put it the other way. (The PHIUS Technical Committee has already taken this definition of Zero Net Carbon into consideration for our PHIUS+ 2018 standard update.)

Moreover, we are pursuing an ANSI-approved passive building standard, via the ASHRAE Standard Project Committee 227P. Participation in Shift Zero should allow us to both contribute to and be informed by a Shift Zero effort on Washington State code.

Our aim here is not to “get PHIUS written into WA code”, nor to “get an ANSI stamp” on PHIUS+ 2015 or even 2018, but to develop something that is both rigorous and more flexible, and of more enduring value. Our current standard is mostly performance-based, that is, based on modeled energy use. This requires modeling protocol, modeling software, and training in using it, for both project planners and verification/enforcement caseworkers. The vision for the ANSI/ASHRAE passive standard is that it would use a combination of prescriptive, performance, and outcome-based compliance paths to support the whole range of project scales – from small projects in backwater jurisdictions with few planning or enforcement resources to large projects in capitols that could take on custom cost-optimization studies. The value of PHIUS+ lies not only or even mainly in the current criteria but rather in the principles and methods underlying them, such as the priority on passive measures and conservation, the constrained cost-optimization for the heating and cooling criteria or the fair-share and national-solidarity principles for total energy use.

The “A” in both ASHRAE and ANSI stands for American. The ANSI mission statement is U.S. focused and the web page has a U.S. flag image. But the ASHRAE mission states pointedly that while they started out in U.S. they now have worldwide membership and global services, advancing sustainable technology for the built environment.

An ASHRAE passive building standard then, ought to be serviceable globally (at least in those parts of the globe that have building professionals.)

In my opinion PHIUS brings a track record of experience and care to this effort, as well as integrity, and humility.

As most of you will know, we started out practicing an “International standard” from PHI in Germany, applying it in the U.S. Our first major adaptation was in 2012 with the addition of greatly expanded quality assurance requirements from U.S. DOE programs. We found that the U.S. building industry simply needed a lot more guardrails on quality. This was in essence a cultural adaptation, as was our early support for the inch-pound unit system. Our second major change was a climateadaptation, in 2015 with the elaboration of the climate-specific criteria for heating and cooling.

To make a long story short, we found that the PHI heating and cooling criteria became disconnected from the principle of economic feasibility that supposedly underlay them, when applied to most climates in the U.S. and Canada, and we set out to redeem that promise. That disconnect affected both the heating and the cooling criteria in different ways, and was apparent in the data of PHI’s own climate parametric study of 20111. As a result of that study, PHI indeed adjusted their cooling criteria, adding to the (not climate specific) fixed base cooling demand a substantial and variable allowance for dehumidification (fair enough, there are not many passive measures that do this.) But the heating criteria still only made sense in one climate, and this was never fixed. Most of the U.S. being heating-dominated we thought that important and so went to work on it in 2013-14.

To make the story just a bit longer, what I would call the first-generation passive builders were splinter group off of the “passive solar” or “solar home” movement in the 1970s. Their differentiation was less mass-and-glass, less gain, more insulation, build light and tight. They tended to speak of “superinsulation” to differentiate themselves from the passive solar people, but passive building really is a better word for it; it’s not just about insulation. The canonical work summing up the first-generation ideas is The Superinsulated Home Book. Their concept of what counted as such a home was a little vague – they speak of reducing the heat losses until the building really starts to “act different” – but the definitional ideas included both low annual heating bills and low peak heating loads, that is, very small heating system capacity required, even to the point where a dedicated furnace was no longer needed; “just steal a little heat from the water heater.” This aspect I think forms the appeal to the heart of the “passive-house flavor” of green building cereal — the “self-heating building,” the “furnace-free house.”

The Superinsulated Home Book

The Superinsulated Home Book was published in the early 1980s, just as the bottom fell out of the solar movement stateside. The torch passed to Europe, and when PHI wrote their definition of a passive house, they focused on that low peak heat load concept and drew a line in the sand on how low it should be — basically, the point where the ventilation and heat distribution systems could be combined. This was reasonable and it does give a target number for design heat load, about 10 W per m2 of floor area, that would apply everywhere, at least in any heating-dominated climate. But when it came to writing certification criteria, an alternate compliance path was added by which one could meet a corresponding annual heating demand. Corresponding that is, in the climate of central Europe. This is the notorious 15 kWh/m2 or 4.75 kBtu/ft2, per year. If a building was designed to meet a peak of 10 W/m2 in central Europe, this is the resulting heating demand.

The problem, I say the glaring problem, is that that alternate criterion doesn’t correspond to the peak load definition in other climates. Again, this is according to PHI’s own study from 20111-2012. They took a study building, moved it around to a lot of different climates, adjusted the upgrades to meet the 10 W/m2 peak heat load definition, and plotted the resulting annual heat demand. It varied a lot, generally increasing as the annual average temperature got lower, but there was a lot of scatter, because annual temperature and peak load design temperature aren’t necessarily that closely related, it depends a lot on how close you are to the ocean.

Nevertheless, the PHI heating criteria remained the same two numbers for everywhere, either 10 W/m2 peak, corresponding to their definition, or 15 kW/m2.yr, which mostly doesn’t. Why? I have always darkly suspected that it is because in continental interior climates, the design temperatures for peak heating load are quite low, making the 10 W/m2 much the more difficult of the two numbers to meet. I think they could tell that it would be impractical for single-family dwellings, even attached like a townhouse end unit, to meet the ostensible definition, and so left the 15 kWh/m2 alternate in there as a close-enough cheat. I say it drives bad design, over-glazing, because solar gains do more to lower the annual heat demand than the peak load. (We showed evidence of this in our PHIUS+ 2015 development report published by NREL.)

Therefore, as I mentioned above, after a few years of applying PHI’s standard in the U.S., and noticing this lack of integrity with the heating criteria, we embarked on a reconsideration of the whole thing, in 2013-14. To my recollection, it just so happened that PHIUS and PHI both officially made standards announcements on the same day, March 15, 2015. PHIUS did make changes to all 3 “pillars” or marquee-level criteria — space conditioning, primary energy, and air-tightness. But, as evidenced by what got elaborated, it was clear that PHI had spent most of 2014 working on primary energy, the big change was the new and more nuanced Primary Energy Renewable (PER) metric, while PHIUS had spent most of that time working on new and more nuanced heating and cooling criteria. To go ahead and put a fine point on it, PHIUS took more care in 2014 with the core concept — the passive measures and how far to push them to drive down the heating and cooling loads.

(I must say it was irksome to get comments like, “sounds like PHIUS+ 2015 is just about bolting on some PV.’ when all we had done was put PV on the same footing as solar hot water, while PHI had spent the whole year working on renewable energy.)

Therefore, I think it is fair to say as a general matter, PHIUS has learned the importance of both “cultural” factors and climate factors to the development of passive building standards, and will bring this to an ANSI/ASHRAE standard development project. The approach to climate I think we have a fairly good handle on, and the multiple compliance options mentioned above should be able to accommodate various “building delivery processes”.

Lately it seems, we hear a lot of glossing over the differences between PHI and PHIUS. “It’s all good” kind of talk, “the differences are for nerds” and the like. At some level, this is fair enough. Yes we heart the furnace-free house, yes we like the EN/ISO 13790 monthly method for annual heating and cooling calculation and the EN 12831 for peak heating load, no we are not trying to be “lite” in general; honestly we get as much “we’re going with PHI because it’s easier” as the other way around.

But at some level the details do matter. In particular when it comes to talking about building energy code, mandatory, enforcement, permits approved or denied, people are going to want to know quite specifically what are the rules, yes?

Let’s think about the most simple and straightforward proposal I’ve heard for a building energy code: enacted in a skit by Henry Gifford and Chris Benedict of New York City, they propose the code consists of just a criterion on the design heating system capacity, that is, a peak heat load. Even with just that, you can see it would take some pages to spell out: by what method or methods of calculation? Do the methods vary for residential versus nonresidential buildings? Are solar gains or thermal mass to be credited with reducing peak loads? By what method are the design temperatures to be determined? Shall these be historical or forward-looking at climate change? Who is qualified to perform the load calculations and to review them? Does the criterion apply zone-by-zone or to the building as a whole? What if I have multiple buildings served by a central system?

So yes, at some level it is fair to say, PHI and PHIUS that is blueberry muesli, all good. But when it comes to the Food and Drug Administration, and to many customers, it is going to matter what is in those blueberries exactly. Are those real blueberries or fake f@#$% blueberries? Are the real blueberries GMO Roundup-ready blueberries or organic blueberries?

At PHIUS I think we have demonstrated some care and forethought in adapting our program and standards in the direction of suitability for incentives and codification in North America, while remaining faithful to the heart of the passive building concept. We will bring this experience and intention to the development of a more widely/globally applicable ANSI/ASHRAE Passive Building Design Standard With Path to Zero Emission or 100% Renewable Energy Society or the like.

ASHRAE requires a fairly public and transparent process and we seek the participation of the best building energy experts anywhere who find this vision agreeable — including PHI, with just one proviso: that 15 kWh/m2 everywhere is not going to make it, that is fake blueberry and we cannot have it in this muesli. If you can let that one thing go at last, the possibilities for fruitful collaboration open up. As those conveners I mentioned in Bonn, Seattle, and Portland have been suggesting, let us get the oars in the water and try to row in a more coordinated way at the goal of a Zero emission / 100% renewable built environment.

1 Schneiders, J.; Feist, F.; Schulz, T.; Krick, B.; Rongen, L.; Wirtz, R. (2012). Passive Houses for Different Climate Zones. Passive House Institute and University of Innsbruck.

 

 

Strengthening the Core

Print

With PHIUS+2018 we took a clear step forward in our commitment to being on the frontline of promoting sustainable energy use in buildings and reducing carbon emissions.

But passive building stakeholders have raised some valid concerns about PHIUS+ 2018 that deserve to be addressed.

The most important concern expressed is that PHIUS+ 2018 appears to move away from the core principle of passive building—that being conservation first and foremost. Rest assured: that principle remains at the core of PHIUS+ 2018. As with PHIUS+ 2015, the foundation of PHIUS+ 2018 is cost-optimized on-site conservation. That core principle is baked into the PHIUS+ 2018 standard, WUFI Passive and heating/cooling energy targets.

Cover image of Certification Guidebook and link to download PDF.

Click to review the update in Section 3.3 of the Certification Guidebook

PHIUS+ 2018 goes further by requiring steps toward net zero source energy, with a mind to carbon reduction. What’s new is that project teams now can also choose offsite renewable energy sources to meet the source energy target.

Despite that change, the core conservation principle never went away—conservation targets on heating and cooling energy still must be achieved using passive measures under PHIUS+ 2018 first.

Some of you have also raised concerns about situations where it’s difficult to go beyond on-site conservation. In particular, high unit density can be problematic. For these circumstances, PHIUS is adding the PHIUS+ Core certification path. Project teams can achieve PHIUS+ Core certification with strictly on-site measures. See Section 3.3 of the updated Guidebook for details.

And, we welcome your input—use the form below to comment.

Regards,

Katrin Klingenberg, PHIUS Executive Director

What’s new in WUFI Passive 3.2

Lisa White

Lisa White

By Lisa White, PHIUS Certification Manager

The PHIUS Certification Staff and PHIUS Technical Committee have been hard at work collaborating with the Fraunhofer Institute for Building Physics (IBP) to upgrade WUFI® Passive. And now, I’m happy to report that the Fraunhofer IBP has released WUFI Passive version 3.2!

This upgrade comes with many improvements, including full support of PHIUS+ 2018 modeling protocols and performance requirements. WUFI Passive is the only accepted modeling tool for PHIUS+ 2018 certification. Below is a summary of updates. Refer to the PHIUS+ Certification Guidebook v2.0, Section 6 for further details.

PHIUS+ 2018 Compliance Updates

PHIUS+ 2018 Criteria Calculator:

Space conditioning targets for a project can be calculated externally using PHIUS+ 2018 Space Conditioning Calculator or calculated within the software when PHIUS+ climate data, HDD65, CDD50, and marginal electricity price in $/kWh are input.

Source Energy Factors:
The source energy factors for electricity were updated, which dropped from 3.16 to 2.8 for the US, and to 1.96 for Canada.

Source Energy Targets:
The residential and non-residential source energy targets have been updated for PHIUS+ 2018. Source energy allowances for process loads in non-residential buildings can also be included in the reported target to verify compliance. See more on ‘Process Load Accounting’ below.

Air-Tightness Limit:
The air-tightness limit under PHIUS+ 2018 has been updated to 0.060 cfm50/ft2 for most buildings. For buildings 5+ stories of ‘Non-Combustible Materials’, there is now an adjusted target reported at 0.080 cfm50/ft2.

Renewable Energy Systems:
New options are included for modeling off-site renewable energy. The options are built in with the appropriate utilization factors according to PHIUS+ 2018 protocols.

DHW Calculation Methods:

PHIUS+ 2018 implements a new calculation method for hot water energy use of appliances, hot water distribution, and drain water heat recovery. See more under Technical Updates.

Technical Updates

Shading Calculation from Visualized Geometry:

WUFI Passive now harnesses capabilities of WUFIplus’ dynamic shading calculation to determine monthly shading factors based on the 3D visualized geometry. This includes shading from the building itself as well as any other surrounding structures that shade the building.

This calculation only takes a few seconds and greatly reduces the need for numerical shading inputs — speeding up the entire modeling process.

shading 3

Reveal Shading visualized:

Due to the new shading method described above, reveal or “in-set” shading for windows is now visualized in the 3D geometry when entered numerically.

Overhangs include ‘side spacing’:

Sometimes overhang depth and position are still in design and it’s easier if they aren’t included in the imported 3D geometry. They can still be input numerically. There is now the option to numerically enter an overhang that spans horizontally wider than the window width or is continuous across a façade.

shading 5

Removed shading landscape obstructions:

Due to the new dynamic shading method, horizontal/landscape obstruction entries have been removed. These may now be visualized in the 3D geometry instead.Accounting for these numerically with the new shading method is a work in progress and will be updated in the future.

Dishwashers, Clothes Washers, Clothes Dryers:

Annual energy consumption and hot water consumption for clothes washers, dishwashers, and dryers now follows ANSI/RESNET 301-2014 protocol, and the required inputs align directly with Energy Star ratings.

New Calculation Method for DHW Distribution:

New and improved methodology for designing and modeling DHW distribution has been implemented. The new method accounts for insulation on non-recirculating pipes, low flow fixtures, can more appropriately estimate hot water distribution losses from on-demand recirculation systems, and includes a tool to aid in the design of a DHW distribution network that will pass the on-site EPA WaterSense delivery test.

DHW 2

Drain Water Heat Recovery:

Drain water heat recovery can be an effective strategy in saving water heating energy by pre-heating incoming water with waste heat from shower drains, etc. A new mechanical system ‘device’ was added to support the calculation of drain water heat recovery when present

Process Load Accounting in Non-Residential Buildings:

A new tab under Internal Loads has been included to account for process loads. This allows for designating loads in the model as process loads. There is then the reporting option to include/remove them within the site & source energy results, and the option to increase the source energy allowance to include that load.

Process Loads 1

*Note: All process load allowances must be approved by PHIUS.

Modeling ‘Undefined’ or ‘White Box’ spaces:
A new non-residential occupancy mode was implemented to support modeling of Undefined spaces, i.e. in mixed-use buildings when a tenant is not yet determined. This simplifies one of PHIUS’ paths to certifying a mixed-use building.

User Friendliness

New Report: Site Energy Monthly Report

In addition to the existing results reports, a new report has been added to support comparison vs monthly utility bills. Previously in version 3.1.1, total annual Site and Source Energy use reports were available. This new report breaks the annual energy use into monthly estimates for both electricity and gas.

Site Energy 1

Updated Tool Tips:

The hover-over hints have been updated to align with PHIUS+ 2018 protocol. Activate them under Options>Usability>Tool Tip.

Case Name in footer of Reports:

In results reports, the project/case name was previously only shown on page 1. Now, you can activate the case name to be included in the footer of each page of the report. Activate under Options>Usability> Show project/case in footnote.

How to Update

Users of the professional version WUFI Passive 3.1 can download the update free of charge. Please log in to your account at the WUFI Web shop, there you can find the update link in the “My Orders” menu.

Free Tutorials: If you’re a beginner in WUFI Passive, utilize these free bite-size tutorials to guide you through your first model — http://www.phius.org/phius-certification-for-buildings-products/wufi-passive-tutorials

New capabilities in  v3.1:

New Heat Pump Device Types:

Two new devices have been added that follow PHIUS’ heat pump protocol. One for a Heat Pump Water Heater (with indoor compressor), and one that utilizes multiple heating COP ratings based on ambient conditions.

Data Recovery:

This is an auto-save feature that allows the user to define how often they want a file to auto-save, and how many ‘total’ files are saved (older versions from the same session drop off). Activate under Options>Usability.

Comment box:
Fraunhofer IBP implemented a comment box which allows users to add a unique comment to each input screen in the software. It can be used to remind yourself of a potential assumption that was made for an entry or use it as a log for model updates due to a change in design. If you’re submitting the project for PHIUS+ Certification, you can provide explanation for entries right in the software (though the feedback form is still the primary communication channel).

F1 for help files:
Before version 3.1, the WUFI Passive manual was a document external to WUFI Passive. The help files have been expanded and are integrated directly into the user interface! This feature can be accessed for any user input screen at any time using ‘F1’. There is an abundance of guidance here – take advantage of it, especially if you’re a first-time user.

Assign Data Button:
Along the top of the screen, an [Assign Data] button allows you to assign an entry (window type, shading entries, etc.) to multiple components at once. Huge time saver.

Export into XML File/Import from XML File:
User defined entries in your databases can be exported to an XML file and then can be shared with colleagues and (WUFI-friendly) friends. This includes all assemblies, materials, windows, HVAC devices, climates, etc. that have been created. Go to ‘Database>Export to XML’, and then select all items that you would like to be saved as an external XML file. If you receive an XML file, go to ‘Database > Import from XML’.

 

PHIUS+ 2018 Webinar Q&A

Screen Shot 2018-12-11 at 10.44.53 AM

PHIUS Senior Scientist Graham Wright and Certification Manager Lisa White answer questions that were submitted during and after the live PHIUS+ 2018 Webinar on November 8, 2018.

You can view a recording of the webinar at the PHIUS.org site.

*Note: Some questions have been edited for publication

Q: Has PHIUS started to look at overall GWP in the materials used to make these high performance buildings? To save the balance of the climate, reducing our emissions in the next 20 years is critical. Lots of XPS and spray foam make a low energy building but don’t do anything to help our climate goals.

A: The short answer is yes. We do have a GWP impact calculator for insulation. Its use is not required for project certification but we encourage it when we see large areas of XPS or SPF proposed. Our product certification program for construction systems has a requirement for a sustainability or health certification; there are several options recognized.

Q: Can you explain the exuberance concept?

A: We remain enthusiastic about the “tiny heating system” / “tiny heating bill” idea.

Q: Thanks for including Quebec Province! I believe in 2015+, all of North America was calculated according to a blanket value for cleanliness of the grid. Is 2018 adapted to different grids, and how do you deal with Quebec’s very cheap and clean hydroelectricity? Renewables are a tough sell here. Zero government incentives and at 7 cents/kWh, our energy costs would have to more than treble in order to make PV make financial sense.

A: In the standard-setting study itself we used the same factor all the time, but because the buildings were (almost) all electric, it canceled out. The PV generation is multiplied by the same factor as the usage, so source net zero is achieved with the same size PV array as for site net zero.

The philosophy is that CO2 emissions anywhere affect everyone everywhere. We all share one atmosphere, so by a principle of solidarity we should really use the world average source energy factor for electricity. That is, people with clean grids do not get to play “we’ve got ours” and use more energy. Even if your local grid is clean we want to drive additional action such as REC purchases that fund new clean energy projects. In certification we do allow the use of national averages, so we actually just request solidarity at the national level. Canada has a cleaner grid than the US overall, and thus Canadian projects will not have to take as many measures for net source energy reduction. The source energy factor for electricity in Canada is 1.96, whereas it is 2.8 for the US.

The electricity cost does affect some of the space conditioning criteria because higher energy prices justify more conservation measures and thus tighter targets. We calculate this with state-by-state averages, so Quebec projects will have less stringent targets than neighbors in Maine and Vermont.

 

Q: The word “townhouse” usually means a single-family building, but you seem to be using it differently.

A: The individual dwelling units are “single-family, attached”. That is, they share walls but not floor/ceiling. Speaking loosely, the whole row of attached units is the Townhouse, and the study building is 8 or 16 attached units.

Q: Is the mandatory minimum for window upgrades done because it wouldn’t be cost effective otherwise?

A: Yes. Window costs have come down but this still had to be forced in most cases. The starting points were still “in the money” though. There were a few times when the optimizer bought them on its own, but it took a long heating season and high energy price to motivate it. 

 

Q: Is this modeled EUI directly from WUFI Passive in the “Modeled vs. Measured” slide?

A: Yes, the WUFI Passive energy model used for certification.

Q: Do the new non-residential commissioning requirements apply to the common areas of residential buildings or only to all non-residential buildings?

A: TBD. Our current definition (for source energy target purposes) hinges on whether the spaces serve outside clients / customers or just the residents.

 

Q: Are you considering using the last 5 years of climate data vs ASHRAE to deal with global weirdness?

A: No, but we are working on future climate data for 2090 as an informational resource.

 

Q: Any comments on using low-iron glass (easily found in EU / just starting to appear in US)? Does the visible transmittance increase relative to ordinary US glass (which has a green tint to natural light)?

A: Alpen for a while had a low-iron glass option in their certified products, but they discontinued it.

 

Q: Instead of ignoring PV in competing with efficiency measures, why not look at PV with storage for the costs? This may not take care of seasonal differences, but it would take care of daily or weekly changes.

A: We may have have explored it if that was an option in BEopt, but it isn’t yet. Our current thinking is that what batteries do for you depends, in normal operation, on what the time-of-use rate structure looks like, and they are also good for you in outage situations. We are working on a calculation protocol for outages and waiting for utilities or other researchers to converge on time-of-use rate structure(s).

 

Q: Is there an ASHRAE 55 comfort analysis or PMV for PHIUS+?

A: The new window comfort calculator is based on relatively recent research on Predicted Percentage Dissatisfied specifically for draft at the ankle – it doesn’t just hark back to the PMV/PPD that was determined in 1970.

I (Graham) also wrote a paper for the 2016 conference looking at the radiant temperature effect of windows on comfort.

In certification we mostly take the same kind of simple view as in building code, e.g., “thou shalt maintain a dry bulb temperature set point of X and Y”. Sophisticated comfort analyses are more appropriate for workplace and nonresidential cases where clothing and metabolic profiles of occupants can be pinned down (as required by ASHRAE 55), and one might not have to worry so much about frail or sensitive occupants.

 

Comment: Adaptation is why I pursued CPHC in the first place!

Graham Wright: Thanks! Lisa presented on passive survivability at the Boston conference, and we will have more to say about this in the future.

Q: How does the new standard accommodate variable occupancy patterns/equipment usage in non-residential buildings?

A: With respect to the performance targets, as a first step, we will allow two different occupancies to be used to determine the annual demand targets vs. peak loads. Also, we can develop custom criteria for unusual situations (additional fee applies).

With respect to energy modeling protocol, it is already required to enter patterns for occupancy, ventilation and lighting, but this is mostly about getting the annual total energy right for source energy limit purposes.

 

Q: Please define HDD65, IGA, CDD50, TCD, IGCL and DDHR.

A: HDD65 = Heating degree-days, base 65 F;

IGA = Solar Irradiance, global, annual;

CDD50 = Cooling degree-days, base 50 F;

TCD = Temperature, cooling design day;

IGCL = Irradiance, global, cooling load design condition;

DDHR = Dehumidification design humidity ratio.

 

Q: If a project is considering registering under either 2015 or 2018, can we register under 2015 then change to 2018 (as circumstances change) without an additional registration fee?

A: Yes, you can always pursue a newer version of the standard. You are not able to pursue older versions if the contract date is later than the last day to submit under that older standard. In order to register for PHIUS+ 2015, the contract must be submitted before April 1, 2019.

 

Q: Are there updates to WUFI to accommodate the 2018+ standard? And when will it be available?

A: Yes, the next version of WUFI Passive will be released by the end of 2018. We will notify all of PHIUS’ mailing list.