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Prior to continuous commissioning, also known as Automated Continuous Commissioning, commercial buildings after construction implemented a onetime fine-tuning or building optimization process. At the very best, these buildings were only being “optimized” periodically (Bi annually, yearly, etc.) as per schedule. This method of commissioning posed major questions among commercial building owners/managers, some of which were: What happens in the period between scheduled commissioning? How can we be sure that the yearly or monthly “optimization” done could sustain the building in the same capacity during the duration leading to the commissioning?
These are good questions to ask as the type of commissioning implemented has an overall impact on the performance of commercial buildings. Due to the concerns raised by industrial and commercial building owners and coupled with technological advancement in the building industry, Continuous Commissioning was developed as a solution. Currently licensed by a Texas based company (Energy Systems Laboratory), Continuous Commissioning is defined as:
“An ongoing process to resolve operating problems, improve comfort, optimize energy use and identify retrofits for existing commercial and institutional buildings and central plant facilities. [It] focuses on improving overall system control and operations for the building, as it is currently utilized, and on meeting existing facility needs. It goes beyond an operations and maintenance program. It does not ensure that the systems function as originally designed, but ensures that the building and systems operate optimally to meet the current requirements.”
Basically, continuous commissioning aims at striking a critical balance between the requirements of two major stakeholders in the building industry – building owners and occupants, whose objectives seem to always be in an inverse relationship. Commercial building investors or owners like any business, have objectives to maximize profits through cost minimization and revenue maximization. Often than not, cost minimization infringes in to the territory of the building occupant’s comfort. On the other hand, commercial building occupants in typical consumer fashion are always on an earnest quest to maximize value for every dollar spent, and hence do not tolerate any comfort infringement in an open and competitive market as that of commercial buildings.
To solve this trade off, the implementation of continuous commissioning takes into consideration both occupant and investor requirements. It is implemented in a manner that optimizes occupant comfort, while improving the value of a commercial building through building optimization that is cost minimization oriented. While other commissioning methods seek to optimize commercial buildings with respect to intended/original plans, continuous commissioning optimizes commercial building operations on a minute-by-minute base, as per the internal and external influential factors.
The implementation of continuous is done through 7 steps as seen below:
1.Visitation of commercial building to identify and quantify potential measures and savings.
This initial stage is very critical to the entire continuous commissioning (CC) process, as it constitutes the base for every other step. In this first step, the firm providing CC visits the commercial property and carries out an initial evaluation of all its systems, especially pertaining to HVAC. This enables the firm to locate those areas in which they could potential cost through the implementation of CC.
2. Development of performance baselines for energy and comfort.
Baselines refer to minimum or generally acceptable standards. With respect to the industry baseline and the commercial building in question, the implementing firm then proceeds to determine the operational occupant comfort standard, in relation to the systems in the building charged with providing this comfort. It could be determined for example that occupants prefer at worst to have AC temperature at 10o. Using this, a baseline could be developed for how the HVAC system can efficiently deliver this.
3. Detailed examination of the commercial building
This step is closely related to the first step, with a primary difference in that the examination of the commercial building is done at an in depth level, taking in to consideration the occupants comfort level and the energy efficiency needs of the commercial building. Whereas stage one is involved with the identification of the potential energy saving areas, this stage goes a step further to analyze each of the identified areas in detail.
4. Implement Continuous Commissioning measures.
This is the core of CC, and it builds on all the 3 previous steps. Continuous Commissioning leverages the Internet of Things, to provide a visual display of the results of installed automations, which provide real time optimization for commercial buildings energy provision and consumption centers. The installed devices, sensors and specialized devices perform optimization functions on the areas determined in stage 1 and 3 with respect to the occupant comfort and savings baselines developed in stage 2.
5. Identify changes in operating procedures for the building staff, and document energy savings and comfort improvements in accordance with the International Performance Measurement and Verification Protocol (IPMVP).
Cost benefit analyses are always at the heart of investment decisions, and investors always expect at all times to see the financial benefits of implemented decisions. This is exactly what this stage is for. At this step, prior consumption and occupant comfort levels are being compared to those after the CC implementation. Further fine tuning could then be done where necessary, and standardizations made. Based on the CC system being installed, proper documentations are then made with respect to changes in line with IPMVP.
6. Training of commercial building staff.
Despite the monumental strides humanity has been taking with technological advancement, we are yet to get to that level where automated processes become completely autonomous. In as much as CC ensures optimal efficiency of commercial buildings, the system in effecting and tracking changes is incapable of carrying out hardware maintenance, which in this case will be have to be done by the staff. Commercial building staff will therefore have to be trained on how to use the new system.
7. Track/verify energy and comfort performance for at least one year in accordance with the IPMVP.
By its very name, continuous commissioning implies an ongoing activity aimed at occupant satisfaction while optimizing building processes with the aim of minimizing cost. Commercial building energy consumption levels, as well as occupant needs are subject to change over a period of time. For example, the winter operational needs for a commercial building and its occupants might differ significantly from its summer needs. Taking this in to consideration, the CC implementation company following international norms must track and verify both energy and comfort performance for a duration of at least one year.
Continuous commissioning and its implementation on commercial buildings are still at their early stages of development. The longest implementation of CC known to date is at the Texas A&M Campus of the Energy Systems Laboratory. Since its initial installation in 1998, the company has gone ahead to install the same system in over 300 different locations, marking remarkable successes in each. Based on published statistics, the system only has a payback period of under 2 years, and the implementations carried out so far all over the globe has saved an estimated $300 million for buildings, while optimizing occupant comfort.
Unlike Retrocommissioning, continuous commissioning uses already installed equipment, and simply optimizes them. As continuous commissioning reaches new hearts, there is no questioning the improved positive impact it will continue to have on the commercial building industry.