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Measuring Energy and Occupant Satisfaction, a Evidence Based Design Presentation
- 1. Measuring Energy and Occupant Satisfaction Evidence Based Design Symposium AIASF April 26, 2011 Scott Shell, FAIA | EHDD Architecture
- 9. Energy Use (Kbtu/sf/yr) Actual: 141 Design: 111
- 10. “We check up on this project to see why it is running 27% above its predicted energy use” GreenSource
- 14. Energy Use: PVs $: $ after Rebate % Total Cost 45% < Code $238,000$158,0001.6 % Chartwell School SEASIDE, CALIFORNIA
- 15. Why Not Zero?
- 17. “Free” Equipment
- 18. User Operation: Site Lighting
- 19. Chartwell: Is the PV Array Working?
- 20. Operation Schedule Net Energy
- 21. 140 120 100 CBECS: 91, all types 80 Actual EUI LEED: 69, all types 60 40 20 0 Medium Energy Type Buildings Certified Silver Gold Platinum Chartwell Actual EUIs (Medium Energy Types) Courtesy of Mark Frankel, NBI
- 27. Controls Incorrect HVAC Plug Loads Lighting
- 30. Net Annual Energy Use (2009)
- 35. Dedicated Ventilation Occupant Satisfaction
- 36. Underfloor Air Occupant Satisfaction
- 37. Thin Building Section Occupant Satisfaction
- 38. The David & Lucile Packard Foundation 343 Second Street Project
- 40. Computer Monitor Energy Use Courtesy of Rumsey Engineers
- 41. Energy monitoring Annual Real Time (actionable) Acoustic Testing during construction Controls Integration Sub Clearly Defined Commissioning Automatic sunshades Lighting controls
- 42. Design Team: Post Occupancy Phase Client Team: Sustainable Task Force
Notas del editor
- Good afternoon. We’ve been collecting two types of data or evidence on our projects: 1. measured energy use and 2. occupant satisfaction data using the CBE online survey.
- EHDD Architecture is a 65 person firm focused on design and high performance buildings.We work on a wide range of building types like the Monterey Bay Aquarium.
- The Exploratorium Science Museum, a zero energy design now under construction
- And Marin Country Day School, a zero energy project
- Looking up the Cool Tower you see the mist ring that cools the air about 15 degrees.
- A night sky cooling system sprays a thin film of water on the roof, which then radiates heat to the cold deep space night sky to produce cool water for use the following day to cool the building.
- The energy monitoring system tracks energy use real time and over the course of time. The measured energy use was about 27% higher than our models predicted.
- GreenSource published the project when it was first completed, and followed up recently with a “Revisit” Article to look at actual measured performance. They lead with this quote, questioning why it wasn’t working as planned. But this misses the point, the comparison should be not be primarily to a hypothetical energy model, but to REAL measured energy use of other labs.
- Compared to the REAL measured energy use of all the buildings in the Labs21 database in this climate zone, it was the second most efficient. We believe architectural practice must fundamentally shift from predictions and claims, to a practice based on real measured data or evidence.
- The project did not meet it’s net zero electrical goal, and the energy monitoring system allowed us to separate out energy use by building, day of week, time of day, and by major systems so we could track down where the energy use was above expectations.
- Some of the energy use was for things that are not typically included in energy models, where were originally designed for code compliance on specific strategies, and not for predicted actual total building energy use. The irrigation booster pump was one of these, along with the rainwater collection system pumps and filters.
- Another variation was equipment brought into the project after it was completed. This used 48” commercial freezer was donated to the school, and these “plug loads” are becoming one of the biggest energy users in our projects.
- The photovoltaic panel energy production is shown here with each dot representing one day’s generation through the course of the year. The total output was around 15% less than anticipated, we don’t know if this was weather related or not.
- Due in part to these variation from our energy model, the total measured energy use the first year was much higher than predicted. After correcting and accounting for some of these items (replacing the commercial freezer, reducing site lighting for security to just what was required) then energy use came down a lot, but not to zero.
- The second case study is the IDeAs office building. We took this ugly tilt up box with no windows, and saw cut the panels on the south side, tilting them down to the ground to for a new courtyard on the south side.
- Here’s the courtyard with new sliding glass doors opening up to the engineering studio inside.
- We punched some skylights through the roof…
- And went from this interior with all the lights on….
- To this interior with all the lights off.
- In this case many of the typical challenges of operation, and unplanned plug loads were not an issue since the client was an electrical engineer who understood how buildings work and was highly motivated to monitor and minimize energy use. The energy monitoring system allowed the client to see what systems were running when they should have been off. The HVAC fans didn’t turn down late at night as shown in the middle of the chart, even though no one was there. Seeing this allowed him to correct the controls sequence so the fans wouldn’t run at night.
- We are very proud of our zero and low energy design work, and are new clients are excited about this too. But at some point they always ask “will it really be comfortable in this building?” So we’ve been doing web based occupant surveys run through the Center for the Built Environment at UC Berkeley to assess user satisfaction. These reports have clear graphic summaries, but also let your burrow into a lot of detail and confidential user comments that are very enlightening.
- It assesses satisfaction on a vertical scale of +3 very satisfied, to -3 very dissatisfied. The hundreds of buildings in their database are then plotted on a curve, and the horizontal axis is the percentile rank of this project compared to the whole dataset. So you see in the upper right that the occupants ranked Acoustic Quality and the building ranked in the 80th percentile compared to all other buildings.
- I’ve taken the 8 projects we have surveys for and put their percentile ranking versus the entire dataset for four different criteria along the top axis, plus an Overall percentile ranking. The bright green cells are in the top quartile, the light green in the second quartile, the yellow in the next, and the red in the lowest quartile of rankings. So you can get a quick picture of how these projects are scoring.
- You can then start assessing which system types are performing well and which less so. This is of course a very small sample, with lots of other confounding factors, but it suggest some patterns for investigation and verification. For example, the four projects with Radiant heating and/or cooling are rated extremely well by the occupants for thermal comfort.
- Likewise, projects with dedicated ventilation system (separate from the heating and cooling system) were ranked exceptionally high for air quality.
- On the other hand, underfloor air HVAC systems were not ranked as highly by the users. There are of course other factors at play here, but this warrants further investigation to try to understand the issue. Diving into the report details make clear that some users don’t know how to adjust their underfloor swirl diffusers, so training and education could improve these scores.
- The buildings with a thin building section (versus larger building footprints) were ranked highly by the users, probably due to close proximity to windows, and the daylight and ventilation they can provide.
- So we’ve been working to incorporate what we’ve learned from these projects into our new designs.
- At the Packard Foundation office, we took a bigger building and divided it into two thin bars since the users have been rating that very highly, and it facilitates daylighting and natural ventilation.
- We also worked very closely with them on the equipment they would bring into the building. We measured all their plug loads, and proposed low energy alternatives and gave them an energy budget that their purchasing group would need to meet.
- We also included good energy monitoring systems so they could see what was working and what was not working as intended, so they could monitor and correct energy performance over time. Knowing that there were a lot of systems with controls on the project, we hired a separate controls integration sub, to make sure that all the controls systems were operating properly and in concert with one another. And finally we had very detailed commissioning spec that included systems that are often left out of the commissioning process, such as the sunshades, blinds, etc.
- Fundamentally we have shifted from a predictive design process, to one that sticks around longer measuring actual building performance and user satisfaction, and then tuning the building in response to what we see. On the Packard Foundation project we added an additional phase to our work to tune the building that first year of occupancy. In addition, it is no longer a building centric approach, but is client centric. They formed a sustainable task force to work with us so they understand the systems, and we understand how they work in more detail. They will have the date and knowledge to run the building intelligently beyond the one year post construction when we are around.