Strengthening the Core

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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’.

 

Step it up from Earth Day to Energy Independence Week

Here’s a great idea from Graham Wright, PHIUS Senior Scientist and Chair of the PHIUS Technical Committee. We hope you’ll take up the challenge.

So, Earth Day was great, and everything. And the Earth Hour there.

Energy Independence Week. It's fun, it's patriotic, and we're virtually certain Stephen Colbert would approve.

Energy Independence Week. It’s fun, it’s patriotic, and we’re virtually certain Stephen Colbert would approve.

But let’s be real, Earth Day doesn’t challenge you to actually do anything in particular, and while Earth Hour does, that is vanishingly little  — one hour out of 8760 is addressing like 0.01% of the problem. After how many years now of Earth Day, what do you say we step the game up?

I call it Energy Independence Week. The idea is that, you extend the 4th of July holiday to a full week, during which you observe these three rules:

1. Use no grid electricity.
2. Burn no fossil fuels.
3. Make no trips to the grocery store.

It’s patriotic and fun. Like a staycation. You’ve got the charcoal grill out anyway. Notice that it’s twice as good even as “1% for the planet” in a couple of ways.

A) it’s 1 out of 52 instead of 1 out of 100, and
B) it’s not just a sacrifice concentrated on you for a diffuse benefit to the planet – it increases your own resilience.

I did this in 2008, a few months before I ever heard of passive house. But I like how it ties in – because of the time of year, it focuses attention on avoiding overheating, not a bad thing. (You will be fine if your passive house is not designed too hot. 😉 And it’s forgiving to the many of us who do not yet live in passive houses; this would be a much harder challenge yet in the winter, in most places.

At the time, I was living in rural Minnesota in a straw bale cottage, so heating and cooling wasn’t a problem. I got by with one solar panel and one battery for electricity. That was enough to run the well pump and my laptop. You don’t need much lighting in Minnesota that time of year. Instead of hot showers I swam in the river, which was a short bike ride away. It’s like camping but, you’ve got all your books or shoes with you.

Your challenges may vary. On rule 3 there, stocking up ahead of time is ok, preparations are part of the idea here. One of the other preparations I made was for irrigation — at the time I was trying to keep a bunch of discount hazelnut seedlings alive in the baking sun. I figured my little panel could not generate enough electricity to run the well pump for that, so I set up a big water barrel so I could gravity feed the orchard. Yeah, I faked it by filling it from the well ahead of time; ideally it would have been a real rain barrel all along.

Again, learning stuff like this is part of the fun. So, I hope you’ll take up the challenge and start planning now. And please, share your strategies, tactics, and experiences in the comments section here at the Klingenblog.

Climate Data and PHIUS+ 2015

 

Adam2smAdam Cohen is a principal at Passiv Science in Roanoke, Va, a PHIUS CPHC®, a PHIUS Builder Training instructor, the builder/developer of multiple successful passive building projects, and a member of the PHIUS Technical Committee. With the release of the PHIUS+ 2015 climate-specific standard, Adam weighs in on the importance of climate data sets.

Project teams have always needed to be discerning about climate data sets they use in energy modeling.  Whether it’s WUFI Passive, Energy Plus, PHPP or any other software, the old adage garbage in = garbage out applies. Project teams always must analyze and make a call as to how accurate the climate file is.

For example, I worked on a Houston, Texas project a number of years ago and there were several climate datasets that were close and one that was very different. As a team, we had to decide how to approach this in the most logical and reasoned way.

Recently as I analyzed a Michigan project, I determined that my two dataset choices were “just not feeling exactly right” so I asked PHIUS’ Lisa White and Graham Wright to generate a custom set. I can’t know that this one is exactly right, but I know that it’s as accurate and “right” as we can make it.

Note that when multiple data sets are candidates, it is not just altitude that matters, but location of weather station (roof, ground, behind a shed, etc.). Ryan Abendroth blogged on the subject of selecting data sets (and when to consider having a custom dataset generated) and I recommend you give his post a read.

Since PHIUS+ 2015 is a climate specific standard, it’s all the more important to use the best available.  We all know that bad data is not exclusive to PHIUS (remember the Seattle weather debacle in early versions of the PHPP).

It’s incumbent on project teams to use science, reason and judgment in interpreting climate data sets. Being on the water, in the middle of a field or in the tarmac of an airport makes a difference.

In New York City, for example, we have an oddity: There are three dataset location choices.

A satellite photo of NYC with Central Park outlined. The climate date for the Park is substantially different than that for other parts of the city.

A satellite photo of NYC with Central Park outlined.

One is Central Park, and the PHIUS+ 2015 targets for that are substantially different than the others. But, counter to a Tweet calling into question the validity of the PHIUS+ NYC target numbers, they are different because the Central Park climate data is substantially different – probably due to vegetation countering the urban heat island effect. It has a dramatic and pretty fascinating effect on the microclimate, and the U.S. DOE has a nice read on the subject.

For project teams lucky enough to have access to multiple data sets for their location, by rational comparison, they should be able to make an intelligent decision to use a canned set or to have a custom set generated.

It also more important than ever that the PHIUS+ certifiers to examine the weather data provided by a project teams to see if the project team made a logical, rather then an easy selection of climate data.

In addition, we on the PHIUS Technical Committee will continue to collect and monitor data and will tweak certification protocols as we see the need. But, I remind all my fellow CPHCs that bad climate data sets are endemic in the industry and it is important that project teams make careful decisions and that they reach out to PHIUS staff to help when climate data sets just don’t seem right.

Comments on climate-specific standards study now open

ClimateSpecificColor
In cooperation with Building Science Corporation, under a U.S. DOE Building America Grant, the PHIUS Technical Committee has completed exhaustive research and testing toward new passive house standards that take into account a broad range of climate conditions and other variables in North American climate zones and markets.

This report contains findings that will be adapted for use as the basis for implementing climate-specific standards in the PHIUS+ project certification program in early 2015. Furthermore, as materials, markets and – climates – change, the PHIUS Technical Committee will periodically review and adapt the standard to reflect those changes.

  • We invite formal comment on the science. Please use this online form to submit. Deadline for formal comment: January 16, 2015.
  • Formal comments will not be public, and are for Tech Committee review only. (The Tech Committee or PHIUS staff will contact you for permission, should we be interested in publishing your comments.) All formal comments will be reviewed, but we cannot guarantee an individual response.
  • Passive House Alliance US Members: An online informal discussion forum is available to all members. The forum discussion will be visible to the general public, but only PHAUS members can make comments. Comments on the discussion forum are not guaranteed to be reviewed by the Technical Committee.
  • If you are not a PHAUS member, use the blog comments section below. Comments on the blog cannot be guaranteed to be reviewed by the Technical Committee. To ensure Committee review, use the online formal comment form.