Taking Correctional Facilities off the Grid: Big Challenge…Big Impact
One of the most effective learning tools we have as designers is looking at the efficiency of facilities we’ve designed in the past and asking, “What have we learned since then that could impact future designs with more cost-effective and energy-efficient factors.” We recently did just that, completing an extensive baseline review of one of our early design examples of a prototype housing unit at Coffee Creek Correctional Facility (CCCF) in Wilsonville, Ore. We revisited the design looking at viable solutions to bring this facility to a Net-Zero Energy solution.
More than other building types, a correctional facility requires uncompromising energy-use levels to guarantee safety and security of staff, visitors and the public typically governed by strict standards of operation set by the Department of Corrections or other industry-specific guidelines. There are also no days off in operating a prison, so the 24/7/365 days of non-stop energy use never diminishes.
By conducting a post occupancy study of CCCF we identified four key findings that will inform our designs of future correctional facilities:
Building Envelope and Orientation – Although a campus may not necessarily be able to make changes in orientation to existing buildings, orientation does need to be considered in relation to placement of renewables and how to maximize energy production through harvesting wind and sun. Additionally, recommended changes factored in higher R-value through thicker rigid insulation within precast concrete walls, increasing R-values from the current R-10 to R-22.
Building Management Systems (BMS) - A computer-based system connected to the mechanical, electrical, fire and security systems not only controls but also monitors these system to create alerts when the building is not operating as predicted. Occupancy sensors in less frequently used spaces, such as program/classroom spaces in a prison, can assist in managing energy use. And the ability to detect lighting levels can allow fixtures to be shut off when day-lighting floods an area with light, reducing light loads by 50-100% throughout the day.
Ground Source Heat Pump (GSHP) – GSHP systems can be costly to retrofit into an existing facility, yet in many geographic regions this is a viable way to naturally heat and cool a building. GSHP harvests heat absorbed at the Earth’s surface from solar energy. Loops of piping filled with water or antifreeze are installed deep underground and pump heat into cold regions in a building during the winter or move heat out of the building into a “heat sink” in the summer. This type of system has been used effectively in many correctional facilities.
Renewable Options – Solar and wind generation are obviously dependent on environmental conditions. A third system that integrates well into a prison environment is biogas or co-generation plants where daily organic waste is converted into biogas and ultimately into energy. In a prison environment, processing waste production is a constant consideration. A co-generation plant operates at a more efficient rate than solar or wind systems using the continual waste product from kitchens and compostables as well as the sewer system.
Our review also showed that the CCCF verifiable energy data for this massive 485,410 SF facility had an Energy Use Intensity (EUI) level of 146.6 kbTU/ yr / sf. The updated Predicted Energy Consumption model based on integrated passive reduction measures we considered could potentially reduce consumables to 79.3 total EUI. Off-setting this lowered energy use would require renewable energy equal to a combined 1 MW PV solar and 1 MW wind turbines or a 2 MW biogas cogeneration plant. These factors were used to create the updated Predicted Energy Consumption Model resulting in a Net-Zero facility.
Considering lessons learned from the sustainable impact of a prison facility well after construction will continue to fuel best practices to efficiently design and operate correction and detention facilities of the future.