Figure 3. Two story manufactured homes at Noji Gardens.

• SIP House: This home, located in Western Washington and constructed by Champion Homes, is the first stress skin insulated panel manufactured home.  BAIHP staff worked with Pacific Northwest National Laboratory to assess ventilation rates.  House tightness was measured at 3.55 ACH at 50 Pa, tighter than all of the 49 SGC homes tested in 2000.  Energy savings are estimated at 50% greater than HUD code minimum.  These results will be presented in Year 5 at the ASHRAE Summer Meeting, authored by PNNL, with contributions from BAIHP staff.

• Zero Energy Manufactured Home (ZEMH): BPA, working with BAIHP staff in Idaho and Washington, provided funding for the most energy efficient manufactured home in the country. The RFP was sent to 18 Northwest manufacturers; Kit Homes of Idaho was selected as the manufacturer of the home.  BAIHP staff solicited 24 industry partners to provide energy efficient building components, including Icynene wall, floor and roof insulation, a low-cost HUD-approved solar system, sun-tempered solar design, and Energy Star© windows, appliances and lighting. Partners include Building America Team members such as Flexible Technologies, Icynene and LaSalle.
  
  The ZEMH was built in August along with a control home.  The ZEMH was displayed at the 2002 Spokane County Interstate Fair before siting at the Nez Perce tribal fish facility near Lewiston Idaho.  Blower door and duct leakage tests at the plant and on-site indicate that this is the tightest home ever tested by BAIHP staff.
  
  Working with FSEC and BPA, BAIHP staff have installed monitoring equipment for the ZEMH.  Monitoring of the home will take place in Year 5.

• NOGI Gardens: Located in southeast Seattle, Nogi Gardens is a 75-home community which has drawn national attention for their two-story manufactured homes, breaking trail for the HUD code home industry in urban, affordable housing.  The project also contains the first two-story, HUD code attached "townhouse homes."  All the homes have been built by Marlette Homes in Hermiston, Oregon to SGC/NC/E-Star specifications.  A blower door test of the building envelope showed 5.0 ACH at 50PA, average for a manufactured home in the Pacific Northwest.  Duct leakage is very low, due to the mastic/riser system employed by Marlette.

• Field Monitoring: The WSU Energy House data has been monitored since year 1.  Monitoring data being collected includes weather, temperature, humidity, CO₂, CO, and 8 differential pressures.  Energy use data from water heat, laundry, fireplace, and HVAC are also being collected.  Monitoring results from the WSU Energy House have been presented to the building science, IAQ and HVAC research communities at ASHRAE, AIVC, HUD/NIST, NFPA and BTECC.  Data is available at http://logger.fsec.ucf.edu/cgi-bin/wg40.exe?user=lubresidence.

Blower door and duct leakage testing indicate very tight ductwork (2.4 ACH at 50 Pa and 61.6 CFM leakage to the outside at 50 Pa.)  Tracer gas testing indicates that the use of a furnace-based intake damper does not change the leakage rate of the home.

• Energy Conservancy: BAIHP staff worked with the Energy Conservancy to evaluate their new products for measuring air handler and exhaust fan flows.

• La Salle Duct Riser: BAIHP staff worked with BAIHP partner La Salle Air to design and produce a duct riser for manufactured homes that uses mastic instead of tape.  BAIHP staff demonstrated prototype designs of the riser to Northwest manufacturers in Year 3.  Three manufacturers (Redman, Fleetwood and Marlette) have adopted the new riser; several others are considering it.  BAIHP staff have also worked with Fleetwood's national office to promote the use of the riser in all Fleetwood plants.

• Flexible Technologies: BAIHP partner Flexible Technologies has developed an innovative system that improves the heat and tear resistance of the duct inner liner, reduces the crimping of ductwork without the use of sheet metal elbows, and an improved system to air seal where the crossover duct penetrates the bottom board.  BAIHP and Flexible Technologies staff have been working with the region's manufacturers to promote the use of the new system.

• Insider Heat Pump: Monitoring of the Insider heat pump at the WSU Energy House was begun in Year 1.  Measured flow rate of the indoor unit was good (850 CFM total, 425 CFM per ton), but BAIHP staff identified two performance issues: a too-frequent operation of the defrost cycle and a lower than expected airflow at the outdoor coil.  Continued testing of the Insider in Year 3 indicated a 10% increase in COP due to increased airflow at the outdoor coil.  During Year 4, BAIHP staff worked with FSEC to analyze performance data on the Insider.

At Vincent Village, the property manager indicated a high degree of satisfaction with the Insider heat pumps, with no comfort complaints since 1996.  One Insider has been replaced; the only other maintenance has been unclogging some condensate drains.

• NFPA-501: BAIHP continues to support the NFPA standards process.  The NFPA standard is typically incorporated into the HUD code, which governs the construction of over 250,000 HUD code homes each year.

In Year 4, BAIHP staff cited Building America research and demonstration efforts in support of successful proposals for standards revision, including duct testing, use of mastic on metal/metal ducts, T-8 lamps, separate vanity light switch, roof solar eflectance > 0.25, and window SHGC < 0.6 cooling measures, and R8 crossover insulation.

• ACEEE: BAIHP staff have co-authored two papers presented at ACEEE Conferences, "Pushing the Envelope: A Case Study of Building the First Manufactured Home Using Structural Insulated Panels," and "Washington State Residential Ventilation and Indoor Air Quality Code (VIAQ) - Whole House Ventilation Systems Field Research Report."

• ASHRAE: BAIHP staff have actively participated in ASHRAE research projects, conferences, symposiums, seminars and forums, including:
  • Moderating a forum on HVAC experiences in HUD code housing at ASHRAE's summer meeting in Year 3.  Over 20 industry and building science professionals participated in the forum.
  • Making a presentation at the ASHRAE summer meeting in Year 4, "Uncontrolled Air Flow in Small Commercial Buildings."  This presentation was sponsored by the Technical Committee 6.3.
  • Authoring a paper on duct leakage, which was submitted and approved for presentation at ASHRAE summer meeting in Year 5.
  • Co-chairing ASHRAE's Technical Committee 6.3 - Residential Forced Air Heating and Cooling Equipment, which is responsible for ASHRAE standard 152 - Thermal Distribution Systems. 
  • Building America research on ductwork and HVAC systems will be included in the next version of the ASHRAE standards.  Building America research will also be a part of future efforts in TC 6.3.
• National Institute of Standards and Technologies (NIST): BAIHP staff continues to work with NIST staff and industry representatives to evaluate ventilation and IAQ issues in HUD code homes.
  • BAIHP staff also worked with NIST and the Energy Conservancy to perform tests on a typical HUD code model house on the NIST campus in Gaithersburg, Maryland.  Testing indicates low flow rates of the whole house ventilation system and significant duct leakage.
• National Manufactured Housing Research Alliance (MHRA): BAIHP staff continues to participate on MHRA's Energy Star committee, which is developing Quality Assurance procedures with USEPA on Energy Star manufactured homes. An article on the ZEMH appeared in the MHRA newsletter.

TASK 2.  PORTABLE CLASSROOMS

This is primarily a WSU (and its subcontractors Oregon and Idaho) and Pacific Northwest National Lab (PNNL) task.  Other partners include FSEC, UCF, IE, the State Energy Offices of Oregon and Idaho, school districts in Portland, Oregon; Boise, Idaho; and Marysville, Washington, regional utilities, manufacturers and other stakeholders in the Pacific Northwest.

The objective of this task is to promote the adoption of energy efficient portable classrooms in the Pacific Northwest that provide an enhanced learning environment, high indoor air quality, and energy savings that are both substantial and cost-effective.  BAIHP staff focus on three main goals:

• Offer technical assistance to portable classroom manufacturers, school districts and related organizations.  Through field assessment, monitoring and analysis, they look at innovative building technologies to determine the value of specific energy saving features and building techniques.

• Serve as facilitators to help build support and develop collaborative agreements among regional utilities, Northwestern portable classroom manufacturers and materials and equipment suppliers, as well as school districts, state departments of education and their affiliates.

• Present workshops and other educational resources to further advance the widespread adoption of energy efficient portable classrooms in school districts nationwide.

2.1 School Partnerships

Pinewood Elementary

Figure 4. Energy efficient portable classroom at Pinewood Elementary School in Marysville, Washington.

An 895 ft² portable classroom (P5) was sited at the Pinewood Elementary School in Marysville Washington, in August 2000. This unit exceeds current Washington State Energy Code standards, with upgraded insulation in the floor, roof and walls, low E windows, and a sensor-driven ventilation system that detects volatile organic compounds (VOC).  A second portable, built in 1985, and also located at Pinewood Elementary (P2), served as the control unit.

Energy use comparisons of the two classrooms show that the energy efficient portable used considerably more energy than the control portable.  This was attributable to several factors:

• Originally, the exhaust fan was hard-wired to the ventilation system that was controlled by a VOC sensor  School district maintenance staff disconnected the exhaust fan from the ventilation control during the first year of the study and hard-wired it into the breaker box.  The upshot of this is that the exhaust fan ran 24 hours a day, non-stop, until BAIHP staff turned it off at the breaker.  The exhaust fan was subsequently re-connected to the ventilation system control, and energy use declined as a result.

• The programmable thermostat was not programmed for holidays and vacations resulting in high energy consumption.

• Blower door testing found twice the air leakage in the energy efficient classroom - 19 ACH @ 50 PA than the control classroom - 9 ACH @ 50PA.  Additional blower door, smoke stick and APT pressure tests indicated that the predominant leakage path was from the classroom through the T-bar ceiling and into the vented attic.  The leakage was a result of an ineffective air leakage barrier. The P2 portable uses taped ceiling drywall, greatly reducing air leakage through the ceiling. 

  BAIHP staff proposed design changes to the local portable classroom manufacturer, including the possible use of SIPs, elimination of the vented attic, tightening the existing ceiling air barrier and sheetrocking the ceiling.

• The HVAC supplier and the school district did not initially commission the HVAC control in the energy efficient portable classroom.  This led to comfort problems resulting in the teacher using plug-in electric heaters during the winter of Year 2.  This problem was identified from conversations with teachers and in a review of energy use monitoring data.  The monitoring data indicated significant temperature variations and high plug-load energy usage.

  In Year 2, alterations were made to the HVAC system (including re-wiring, replacement of the ventilation system’s VOC sensor with a CO₂ sensor, and modifications to other aspects of the HVAC control system) by school maintenance staff, district maintenance staff, and the HVAC system supplier. Calibration testing done by scientists at the Florida Solar Energy Center on CO₂ sensors showed significant drift in output results.  Staff from WSU, OOE and IDWR are recommending that occupancy sensors be used in place of CO2 sensors.

• Another problem with the energy efficient portable, related to indoor air quality, is that the fresh air intake and exhaust fan are positioned in such a way that they create a “short circuit” of fresh air, bypassing the students and teacher.  BAIHP staff have proposed locating the exhaust fan for future portables on the wall opposite the supply air vent.
  

  The experiences working on the energy efficient portable were instructive, particularly in the identification of flaws in portable classroom design.  The difficulties that BAIHP staff encountered demonstrate the importance of well-defined commissioning protocols, documentation, and coordination among all personnel that service and install HVAC equipment.

  Figure 5. Graph comparing heating system use of the Pinewood control portable (P2) with the energy efficient portable (P5). Note the energy efficient portable’s high energy use during the Christmas holidays due to incorrectly configured heating system controls