This post highlights the important role that building commissioning must play in any Net Zero Energy strategy.
A Net Zero Energy project is a building or group of buildings with significantly reduced energy loads, such that 100% or more of the energy use can be met with on-site or off-site renewable energy generation annually.
There are several factors driving the push toward Net Zero Energy, including increasingly stringent code requirements and reference standards (IECC 2015, ASHRAE 90.1 2013, IGCC, LEED) (source), changes to Architecture 2030, rising electricity costs, advancing municipal codes, changes at the federal level, and climate commitments in the public sector.
Compared to conventional building practices, Net Zero can seem like an insurmountable challenge. But the truth is that Net Zero Energy is possible and very achievable. In 2012 there were 60 buildings in the world that were either near Net Zero Energy or had achieved it. As of this publishing, the number has risen to 580 – that’s a 967% increase in just 7 years.
Let’s talk about Commissioning
Commissioning may be the single most cost-effective strategy for reducing energy, cost, and greenhouse gas emissions in buildings today. If you aren’t familiar with Building Commissioning, you can read our primer here: https://www.paladinoandco.com/blog/understanding-building-commissioning/.
Commissioning has a critical role to play in a Net Zero Energy project.
Design Phase
One of the first ways to engage the commissioning team is by having them work with ownership to develop a quality OPR (Owners Project Requirements). This document will assist the design team in developing the project documents to meet the owner’s lofty goals.
The energy modeler, Cx team, and project design team (architect and engineer) should collaborate closely through an integrated design process to fully incorporate the OPR and take advantage of the results of the energy modeling.
During design, the Cx team should run a sensitivity analysis to determine whether to start with the building purpose, block and stack, skin, active systems, building operations, or renewables.
A sensitivity analysis determines how different values of an independent variable affect a dependent variable under a set of assumptions. Sensitivity analyses are also sometimes called “What-if analyses”.
The Cx team will back-check the energy model.
Whether commissioning a Net Zero Energy building or a conventional building, the commissioning process and goal to provide a building that works and satisfies the owner’s intent remains the same. The differences for a Net Zero Energy building are likely to be: there may be more systems and equipment in the commissioning plans; the systems may include new or innovative technology that also may require specialized expertise; extensive control system integration will require integrated system testing; building operators may require additional training; and there must be greater commitment to the proper operation of the building post-occupancy.
In addition to traditional MEP commissioning, incorporating enclosure commissioning into Net Zero projects is critical. Problems with the enclosure can greatly affect the performance of the building and negate the improvements incorporated in the design. A thorough design review will start the project in the right direction while a detailed functional performance testing plan will help ensure the systems are installed and all properly incorporated. A well-designed system will not perform as intended if the envelope does not effectively address heat, moisture, and air flow. This white paper by BASF provides additional details and is a worthy read. The bottom line is that the commissioning strategy must include building envelope commissioning.
Construction Phase
While Net Zero Energy Buildings are still considered innovative, there are recognizable and standardized systems being used in typical Net Zero Energy buildings. For example hydronic and radiant systems; chilled beams and ice storage for energy storage; variable refrigerant flow; ground water heat pumps; advanced lighting control; renewable energy systems; automated shading devices; advanced plug load management; dedicated outside air systems; and heat recovery. Many of these are also used in conventional designs.
In order to maintain an awareness of the energy performance and to assist with Measurement and Verification plans, it is important to calibrate and properly place sub-meters to identify end-use consumption throughout the project.
Post-occupancy
Because Net Zero Energy focuses on the performance of the building, there is a greater need for monitoring and recording building performance data. Whether using submeters or a solution like Clarity, building owners and operators must continue monitoring building performance and correct inefficiencies throughout the lifecycle.
Continuous commissioning will help prevent energy issues from developing and the Net Zero Energy target shifting out of reach.
Closing
While it’s reasonable for architects and developers to think of Net Zero Energy as a design goal, it’s actually an operational goal as well. A Net Zero Energy designed building needs to be constructed and operated for Net Zero Energy.
So the question is not “Will I need to drive a building to Net Zero Energy?” –the question is “How will I drive a building to Net Zero Energy?”.
In terms of commissioning, the project schedule and budget should include:
- Integrated design process
- Energy modeling
- Sensitivity analysis
- Fundamental Commissioning
- Enhanced Commissioning
- Building Envelope Commissioning
- A Measurement and Verification Plan
Paladino has published an e-book that explains our six-block method to achieve Net Zero Energy for new and existing buildings. It’s a quick and insightful read that you can download here: https://www.paladinoandco.com/download-center/net-zero-download-page/