A pilot study is underway to gauge the effectiveness of phase change material to reduce and shift HVAC load at a new high school outside Phoenix, Ariz.
Canyon View High School, which opened last month in Waddell, features a number of energy-saving technologies and products, including BioPCM mats made by Phase Change Energy Solutions. Two nearly identical buildings – one with BioPCM installed in walls and ceilings, one without – will allow the effect of PCM to be measured. Each building is roughly 30,000 square feet and each has two levels of classroom spaces.
DLR Group, which designed Canyon View, funded the pilot study, with contributions by Phase Change Energy Solutions and Chasse Building Team. During the yearlong study, HVAC energy use and interior temperatures will be recorded in both the test and the control buildings.
Mark E. Richards, right, served as project manager, applications engineer and systems installer for Phase Change Energy Solutions. He answered questions about the project.
Q: What factors did you consider in developing a plan for PCM type, quantities and location?
A: "Available space for PCM to fit within the architectural requirements. Also the HVAC loads as well as design temperature criteria."
Q: Describe the BioPCM products chosen for this project (peak melt points, thermal storage capacity, containment media).
A: "ENRG Blanket powered by BioPCM Q23M27 and Q23M51."
Q: How are the BioPCM mats recharged? Using the HVAC system, nighttime air, or other means?
A: "Initially we will be using the HVAC system. The purpose of the study is to experiment and determine the most economical solution. The second floor can do a night purge more effectively since it has large air-handling unit. The first-floor systems are 2 pipe fan coils."
Q: Describe the equivalent (non-PCM) spaces in the control building. Were standard construction materials and techniques used in walls and ceilings?
A: "The test spaces are of equivalent construction, use and orientation. Metal frame, with rigid and batt insulation, plaster (stucco) exterior and drywall interior. Roof is metal deck with foam on top. See CVHS BioPCM Test Rooms. These show the rooms that have all six surface temperatures monitored as a part of the thermal comfort analysis."
Q: Describe the two types of HVAC systems used in each building.
A: "Chiller water fan coils with electric heat serve first-level zones and a single chilled water air handler with variable air volume boxes with electric resistance reheat per zone serves the second level."
Q: What modifications are needed to typical HVAC systems used in this type of building to optimize the performance of the BioPCM products?
A: "No physical changes required. We will experiment with building management system sequence of operations to determine optimal settings."
Q: ENRG Blanket is produced in three fire class ratings, Class A, Class C and Plenum. Which were used in this project? Did local building codes present any special challenges in material selection or deployment?
A: "We used class A material as required by International Building Code and look at authority having jurisdiction. There was no material installed in a return air plenum."
Q: Have you used thermal modeling to project the level of cost savings?
Q: How will energy savings be calculated?
A: "Since we are measuring HVAC energy for the chilled water and electrical power in five-minute intervals we can monetize easily based on the local tariffs and compare the PCM building directly to the non-PCM building. We have separate HVAC power metering for each floor."
Q: Is there anything you’d like to add about the project?
A: "DLR Group, specifically Premnath ‘Prem’ Sundharam, global sustainability leader for DLR, came up with the concept to leverage a DLR Group innovations grant funding opportunity to test BioPCM not previously been done at this scale. This pilot study, known as Thermal Mass 2.0, would not have been possible without his enthusiasm and vision. The Agua Fria Unified School District is also to be recognized for being a willing partner in this effort as well as Chasse Building Team for helping coordinate the installation of the data acquisition system (DAQ).
"The installation of DAQ system was challenging and costly. Phase Change Energy Solutions provided the BioPCM, the DAQ equipment and labor to install it significantly below cost. Dr. Reyad Sawafta, chief technology officer, and Scott Queen, VP sales, should be recognized for their commitment to proving PCM performance at this scale. We should have a pretty good idea how the two buildings compare to each other by the end of the year and look forward to analyzing the data.
"We are also studying the thermal comfort effects of BioPCM by monitoring surface temperature in two classrooms in each building of the same, type, use and occupancy. All six surfaces of each room are logged every five minutes. We monitored room temperatures during construction before the HVAC systems were active and after the PCM was installed to see how the PCM performed in a passive application. The PCM rooms were on average 2.1 F cooler than non PCM spaces pre-HVAC system operation. See chart."