Interface Engineering Education Series 2: Private Schools by Interface Engineering

Education Series part two of three

PRIVATE SCHOOLS CASE STUDY

building for the future. written by: Jared Doescher pe, leed ap associate, senior mechanical engineer 2

Steve Gross pe associate principal, sr. energy analyst

Sonoma Academy Janet Durgin Guild and Commons a net postive case study

Interface Engineering provided full design services (HVAC and Plumbing), as well as sustainability consulting, energy modeling services, commissioning and measurement and verification (M&V) for Sonoma Academyâ&#x20AC;&#x2122;s new Janet Durgin Guild & Commons building totaling 19,300 GSF located in Santa Rosa, California. The Studios and Grange building encompasses computer and electronics labs, maker spaces, dedicated tutoring spaces, faculty offices, and a full-service kitchen and dining hall space for the Sonoma Academy college preparatory high school. The project has achieved LEED Platinum certification and is generating more energy than it consumes each year, achieving Net Positive Energy performance. The project is also in the process of achieving its Living Building Challenge Material and Energy petals. The building was first occupied in the winter of 2018 and has just completed the M&V phase.

WRNS STUDIO ÂŠ MICHAEL DAVID ROSE

Â© MICHAEL DAVID ROSE

The major goal for the Studio and Grange building at Sonoma Academy was to provide a net positive energy building that met the Living Building Challenge.

radiant floors

ENERGY EFFICIENCY AND SUSTAINABILITY

Minimizing the environmental footprint of Guild & Commons was a focus for all members of the design team, starting from the inception of the project. Interface’s Building Performance Team worked with WRNS Studio and our Mechanical and Plumbing teams to optimize the building’s systems and envelope components to achieve Net Positive Energy performance using IES-VE energy simulations throughout the project. The final design incorporated a number of passive and active design strategies that include: » Geoexchange ground-source heat pumps (GSHP) with integrated heat recovery » Fossil fuel free radiant heating and cooling » 100% electric food service equipment, including induction ranges and griddles » Dedicated outside air systems with energy recovery

heat pump chiller

» Variable speed kitchen exhaust with smart controls » Ceiling fans (further reading) » Natural ventilation through operable doors and windows » Domestic hot water preheating from GSHP

radiant ceiling

make - up air unit ceiling fans

pumps heat recovery ventilator

geoexchange

» High performance glazing with optimized shade structures and tunable exterior shading » Interior daylighting via skylights » All-LED lighting with daylight harvesting

» Rainwater treatment and capture system, used for toilet flushing » Green roof and bio swales are used extensively to reduce run off to storm water system

controls achieves 75% reduction in lighting energy » Roof and ground mounted solar

» Greywater is captured from restroom lavatories and discharged to bioswales

photovoltaic (PV) panels

Interface has competed 12 month’s of M&V that has revealed the building is performing 1% better than excepted, achieving an EUI of 36.7 kBtu/ft2-yr from March 2019 to February 2020. The annual renewable energy production, however, was 6% below expected output due to a very wet and cloudy El Niño winter. The monthly energy balance, which is the difference between the renewable production and the building consumption, is shown in the graph at right.

Over the 12-month period, the building consumed 7.5% less energy than produced by the renewable energy system.

70,000

60,000

Energy Balance kWh

The final design-phase energy analysis projected a site energy use intensity (EUI) of 37.0 kBtu/ft2-yr and a 38% energy cost reduction over an ASHRAE 90.1-2007 baseline building. The building’s 143 KW of PV panels were predicted to offset 114% of the building’s annual energy consumption with the goal of achieving Net Positive Energy certification through the Living Building Challenge.

50,000

40,000

30,000

20,000

10,000

(10,000) MAR

MAR

APR

MAY

Predicted Balance Trend

Net Positive Energy Balance

Measured Balance Trend

28,752 15,492

JUL

AUG

SEP

OCT

NOV

DEC

JAN

7.5%

NET POSITIVE ENERGY

FEB

INDOOR AIR QUALITY

This Studio and Grange building is designed with anemphasis on indoor air quality. The offices and tutor rooms were designed to utilize natural ventilation with operable windows meeting ASHRAE 62.1-2007 natural ventilation design requirements. The other spaces in the building were designed to have mechanical ventilation designed to provide 30% more outside air at all design conditions over the ASHRAE 62.1 â&#x20AC;&#x201C; 2007 ventilation requirements and with MERV-13 final filters to meet LEED IAQ requirements. Carbon Dioxide sensors in all the spaces provide demand control ventilation for densely occupied spaces. To meet the Living Building Challenge and LEED requirements exceptionally low VOCs are present in the building. The mechanical ventilation systems included energy recovery devices. Although in the Bay Area, energy recovery has limited if any energy reduction payback, it was determined that the cost of the energy recovery reduced the heat pump capacity (could install smaller heat pumps) as well as the geoexchange grid (due to peak load reduction as well as impact on the soil temperature over 50 years). The combination of the savings made the energy recovery devices an instantaneous return on investment.

ÂŠ MICHAEL DAVID ROSE

Â© MICHA

OPERATION AND MAINTENANCE

The Studio and Grange Building mechanical system options considered during the design phase included central airsource heat-pump, central heat recovery water-cooled heat-pump, and non-heatrecovery water-source heat-pump. The lowest maintenance, operations and replacement cost option was the heat recovery water source heat pump with geothermal field. The geothermal field will have little to no maintenance requirements for its lifetime as compared to typical cooling tower which requires significant water treatment and shorter life span due to exposure to the outside, the geoexchange system also would not require any need for heat injection from fossil fuel sources during the winter months. The radiant heating and cooling systems help reduce maintenance and operations costs. By reducing the volume of air down to ventilation only, supply and exhaust fans can

be reduced in size and are able to be direct drive fans, both of which reduce maintenance costs and complexity. Our extensive experience with radiant systems in conjunction with our deep knowledge ascertained from measurement and verification of such systems allows us to design to real world performance rather than overly conservative engineering. A THOUGHTFUL TEAM

A truly high-performance building does not come together by chance or coincident. It is the product of the dedication and passion of every stakeholder involved. We are thankful to WRNS Studio for their vision of a more sustainable built environment and for trusting us as their partner for the mechanical engineering, building science modeling, commissioning, and measurement and verification. We commend and congratulate the Sonoma Academy community for supporting such an ambitious and inspiring project, and allowing our team to pursue our passion for innovative engineering solutions.

AEL DAVID ROSE

select private school experience

Cascades Academy of Central Oregon BEND, OREGON

• Earned Citation Award: Built Category, AIA Portland, 2013 and Best of Education, IIDA Oregon Chapter, 2014 • A geothermal heat pump is the primary heat source taking advantage of the excavation required for the playing field on the rocky site. The school is heated by exposed radiant slabs. The gymnasium, constructed with insulated concrete forms, relies entirely on passive cooling and ventilation with large ceiling fans and air intakes with automated dampers.

Victory Academy SHERWOOD, OREGON

• School for K-8 students on the autism spectrum. • Sustainable features incorporated into the design include natural ventilation, radiant floor slabs, low-flow water conserving fixtures, CO2 sensors and building mass pre-cooling using night time flush.

Stone Ridge Student Life Center LEED SILVER GOAL BETHESDA, MARYLAND

• The Student Life Center at the Stone Ridge Campus is a new, multi-use building, approximately 50,000 sf designed to achieve LEED Silver. • Energy-saving mechanical systems include VRF for the classrooms and individual rooftop units for the cafeteria and dining area. These systems were designed to save on equipment size and quantity which in turn allows for higher ceilings and lower energy use.

BASIS Independent McLean MCLEAN, VIRGINIA

• Awards: Merit Award, K-12 Education, ENR Mid-Atlantic; Excellence in Construction, Associated Builders and Contractors (ABC) Metro Washington • Conversion of an existing 65,000 sf commercial office building into a new private K-12 school, developed to suit the STEM-focused, liberal arts program.

Sacred Heart Academic Building ZERO ENERGY + LEED GOLD GOALS ATHERTON, CALIFORNIA

• New 69,000 gsf academic building: flexible learning spaces, inquiry labs, administrative spaces, communal spaces and music and dance spaces.

Â© WRNS STUDIO

The Mirman School for Gifted Children: Phase 1 Learning Center LOS ANGELES, CALIFORNIA

• School Expansion will accommodate K-12 within a 6-acre school campus • Phase I - New 45,000 SF, three-floor academic building • Improvements to Existing Facilities

creating optimal environments for learning. 100 SW Main Street Suite 1600 Portland, OR 97204

601 S Figueroa St Suite 2790 Los Angeles, CA 90017

100 S Wacker Drive Suite 1140 Chicago, IL 60606

135 Main Street Suite 400 San Francisco, CA 94105

815 First Avenue Suite 312 Seattle, WA 98104 1003 Bishop Street Suite 750 Honolulu, HI 96813

2000 M Street NW Suite 270 Washington, DC 20036 www.interfaceengineering.com

covers Sonoma Academy Janet Durgin Guild + Commons LEED PLATINUM, ZERO ENERGY CERTIFICATION, LIVING BUILDING CHALLENGE, + WELL BUILDING CERTIFICATION GOALS