Guidelines for Phius 2021 & District Energy System

In this week’s blog, Phius Project Certification Manager James Ortega clarifies the guidelines for projects pursuing certification that are connected to a District Energy System (DES).

In response to a number of university and campus projects inquiring about certification, Phius would like to share clarifying language and guidelines for certifying a building connected to a District Energy System (DES). 

DES is a network of hot and cold water pipes, typically buried underground, that are used to efficiently heat and cool buildings. These types of systems typically use less energy than if the individual buildings served by them were to each have their own boilers and chillers. DES are historically served by fossil fuel burning equipment, but modernization of these systems can involve switching to geothermal energy.

Regardless of the type of fuel used to run the DES, Phius has two certification strategies to account for their benefits:

1. The Building as the project ‘Site’
   1. Source energy factors for systems tied to the DES are ascribed the associated average source energy factor from Energy Star portfolio manager (Figure 1).
   2. Equipment tied to the DES is to be modeled with an efficiency of 100%.
   3. Any campus-installed renewable energy is considered off-site, unless it is installed directly on the building pursuing certification.
   4. Phius CORE 2021 certification is available.
   5. Phius ZERO 2021 certification is available.
2. The Campus as the project ‘Site’
   1. Source energy factors remain the same as outlined in the Phius Certification Guidebook, Section 6.2.3.
   2. Equipment tied to the DES is to be modeled with an efficiency equal to that of the DES.
   3. Any campus-installed renewable energy is considered on-site, including systems installed directly on the building pursuing certification.
   4. Phius CORE 2021 certification is available so long as the team provides a plan to electrify the system in the future. 
   5. Phius ZERO 2021 certification is available only for DES with no fossil-fuel combustion.

Have questions? Feel free to contact us with any questions regarding guidelines for certifying a building connected to a District Energy System.