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

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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.

 

 

 

 

 

 

 

 

PHIUS Offers a SMART Path to Carbon Neutral Building

Recently, leaders of 19 of the world’s largest cities announced they would enact regulations to require new buildings be carbon neutral by 2030, and all buildings by 2050.

We at PHIUS wholeheartedly endorse this powerful commitment to sustainable development. We continue to work with all stakeholders in the design, construction, manufacturing, real estate, finance, and government sectors to eliminate the building sector from the global carbon balance. We need to move from a broad vision for a carbon neutral future to specific focus on tangible, actionable steps for these industries that so profoundly affect the built environment.

To borrow from management consulting-speak, passive design is a SMART way to go carbon neutral. For the uninitiated, let’s see how PHIUS is the S-M-A-R-T way to tackle carbon in buildings.

Specific:
PHIUS+ sets limits on net source energy—the total amount of energy consumed through production, conversion, transmission, distribution, and ultimately into useful energy services at the building site. When setting PHIUS targets, we apply a national average source-site adjuster for delivered electric energy to reflect the inefficiency of the electric system and to follow the fair share of carbon principle. Inversely, by specifically increasing efficiency of space conditioning end-uses, we deliver a triple benefit upstream! Through onsite generation, virtual net metering/community solar, and REC purchases, project teams can remove their project’s specific carbon footprint from the bigger equation.

Measureable:
You can’t manage what you don’t measure, so we developed a whole Monitoring Protocol to gauge not just energy consumption, but overall project performance. We also look back at projects in operation to see how they perform compared to the modeled results . Bottom line: across the nearly 200 units and homes we studied, PHIUS projects are within 10% of their predicted (modeled) energy performance.

Attainable
We take the global goal of carbon neutrality and make it attainable for project teams working in their particular climate context by providing tools, training, and technical support. PHIUS+ is the only cost-optimized passive building standard, meaning that exceptional performance is economically viable. Most importantly, we convene a community of practitioners so that professionals can share experiences, insights, and develop best practices to take high-performance building further, faster–making the sustainable…attainable.

Project teams are constantly finding innovative, cost-effective, and elegant solutions to achieve the ambitious (and necessary) energy performance targets. See our Passive Project Design Awards for compelling examples.

Relevant:
As our friends at Architecture 2030 like to put it, “Buildings are the problem; buildings are the solution.” Buildings represent roughly 40% of US energy demand [31% globally], with growth overwhelming increases in efficiency. Passive building at scale could go a long way towards the necessary reduction targets. Moreover, the source energy targets are based on a “global fair share” of carbon emissions.

Time-Bound:
We recognize the magnitude of the climate challenge, and we are committed to taking bold but measured steps so ambitions align with abilities. Like building codes and other rating systems, we have a process to revisit and revise standards every three years. The PHIUS+ 2015 Standard will be phased out in the coming months and replaced with the PHIUS+ 2018 Standard, which sets updated targets, addresses different building types, and allows creativity and flexibility to achieve the performance targets.
Get SMART with your plans to positively impact the future, and join the community of practice that’s forging the passive path to meaningful climate action.

Healthy Buildings, Part 2: The PHIUS Phive

Earlier in the week, we discussed the Harvard TH Chan School of Public Health’s 9 Foundations for a Healthy Building.

When building to minimum building code standards, these items do not seem connected because the building is not designed as a system as much as it is designed as a collection of parts. Building codes are minimum standards that aim to ensure health and safety concerns are less of a concern for consumers. In high-performance building, such as passive building, a lot of these items piggy-back on each other. For example, proper ventilation and thermal control tend to improve air quality while reducing moisture, dust mites, and pests. Thermal control also generally improves acoustical comfort. PHIUS+ certification specifies continuous insulation, airtight construction, and proper ventilation using small and quiet mechanical systems and great windows. Other aspects on the list of nine—which affect indoor environmental quality, but which are not required for PHIUS+ certification (daylighting, acoustical comfort)—are often part of the PHIUS+ package because that is just good design, and PHIUS buildings are designed by people who give a damn.
5-Passive-Building-Design-Principles

The five PHIUS+ principles:

1/ Continuous insulation

By completely wrapping a building with insulation, heat can no longer sneak out through framing, which has a lower R-value than the surrounding insulation. The simplest way to fix all of those energy sieves is to avoid building them in the first place. Continuous, thick, insulation on the outside of a building keeps heat flow to a minimum.

 

2/ Airtight construction

While thick, continuous insulation can stop a significant amount of heat loss through conduction, plugging air leaks can slow heat flow, too. Because temperature drives air movement—think about convection loops—the air moving through buildings usually carries a lot of heat with it. So here’s the rub: Warm air can hold more moisture than cold air. So when warm air leaks through electrical outlets into exterior walls, it dumps moisture into wall cavities when the moist air hits the cold wall sheathing. It happens in winter and summer, only in reverse.

 

Sound waves also travel on air currents and through framing members, so these first two principles have the added effect of better sound control.

 

3/ Optimized windows

The appropriate window depends on your climate zone; cold climates need well-insulated windows because the temperature extremes are significant. Hot-climate windows typically have strong radiant-heat blockage because the sun is intense in hot climates. Another aspect of windows is shading, which can reduce glare and overheating, and is often cheaper that additional window technology. Regardless of climate or wall elevation, very good double-pane and triple-pane windows which are designed to be airtight are great from an acoustical perspective, they tend to be super quiet.

 

4/ Balanced ventilation

Air-tightening means that dirty, moist air isn’t leaking into the living space from basements and loading docks, which is good. It also means that stale indoor air is not leaking out, which is bad, so air changes must be controlled with some sort of high-tech fan. With balanced ventilation and a tight envelope, a constant flow of fresh air flushes the living space and conditions it to be perfect for human comfort.

 

Ventilator filter required min Merv 7, highly recommended to be MERV 13

 

5/ Minimal mechanical system

Because the building is super-tight, super insulated, and has super windows, a super-size heating and cooling system is unnecessary. A great side effect of minimal mechanical systems is that they are much more quiet.

 

When these five principles are applied to buildings, you get predictable performance, unmatched comfort, superb air quality, and resiliency in the face of power outages due to winter storms or summer blackouts. We can say that PHIUS+ is the most cost-effective path to the Harvard list of healthy building foundations because the core objectives of PHIUS+ address the concerns of healthy building. Healthy buildings are a byproduct of PHIUS+ certification.

 

Best of all, because PHIUS+ buildings consume so little energy, zero energy is easily within reach.

 

Healthy Buildings, Part 1: 9 Principles

An article in ArchDaily details the nine aspects of a building that, according to the Center for Climate, Health, and the Global Environment at Harvard University’s School of Public Health, make that building a healthy place for people to be. The ArchDaily article summarizes a 36-page report called The 9 Foundations Of A Healthy Building. It is not a surprise to PHIUS what the nine items are, or that PHIUS+ certification is the most cost-effective way to get there (more on that later).

9_Foundations_Healthy

A summary of Harvard’s Nine Foundations of a Healthy Building:

Ventilation — Replace stale indoor air with filtered outdoor air. Test, maintain and monitor equipment regularly.

Air Quality — Eliminate items that offgas, remove legacy pollutants (lead, asbestos, PCBs), limit moisture intrusion. Relative humidity should be kept between 30% and 60% to reduce mold and mildew odors.

Thermal Health — Control humidity and temperature striations. If occupants need control of the thermostat, make that easy. Also, stick to a regular maintenance schedule to make sure equipment is running efficiently.

Moisture — Roofs and walls should not leak, plumbing and HVAC equipment should not condense or leak, and condensation spots (cold spots that become mold spots) should be eliminated or monitored (this is done with continuous insulation, as explained later).

Dust & Pests — Surfaces should be clean, and vacuum filters should be high efficiency because dust is a reservoir for allergens and chemicals. Generally, the focus is on preventing problems (more about solutions below). Airtight construction, described below, also keeps pests out (including bed bugs in apartment buildings, through compartmentalization).

Safety & Security — the items outlined in this section are required by building codes, including fire and carbon monoxide detectors, lighting in stairwells, egress, entry, and parking areas.

Water Quality — beyond a city water supply that meets water quality standards, consider water purifiers and microbial control. Plumbing layouts should be designed to minimize stagnation in pipes.

Noise — beyond outside noise, indoor noise should be controlled. Background noise should be limited to 35db with a maximum reverberation time of 0.7 seconds.

Lighting & Views — Daylighting should be abundant in natural blue light, evening lighting should be devoid of it. Views to the outside and outside-inspired interior themes connect people to nature which can significantly improve recovery from stress and mental fatigue while boosting their cognitive performance.

While nine items is a little more than most people can recall quickly, the point of the Harvard exercise was not to make a snappy list that people could quickly remember but to make a list that accurately reflects healthful buildings. Fortunately for high-performance builders and designers, PHIUS can shorten the list.

Check back later this week to see how the Harvard Healthy Nine translates to the PHIUS Phive!