Managing Energy Use
As part of the energy management and technology basics track, Charles Miltiades, senior controls engineer, Mitsubishi Electric Cooling & Heating, presented, “Your HVAC System Can Manage Its Own Energy Use: Advantages of VRF Systems.”
A variable refrigerant flow (VRF) system can “minimize energy use while maintaining comfort,” said Miltiades. VRF can act as an energy recovery system. It can pull heat that would be rejected in cooling a portion of the building and use it for heating another portion of the building.
The building load changes depending on where the sun is in relation to the building. The load can also change based on occupancy, such as occupancy in a conference room. VRF can accommodate that by transferring heat to another part of the building.
“A control algorithm determines who gets more heating or more cooling,” he said.
A VRF central plant requires no extra controls; everything is in one box and no custom integration is required. For owners, VRF saves space and saves energy. For building occupants, you can have individual zone control and simultaneous heating and cooling.
Highlighting a case study at Pacific University, Miltiades said 67 percent less gas is used; 28.9 percent less kWh is used. It is the first Leadership in Energy and Environmental Design (LEED) Gold VRF project in the United States.
Donald Wulfinghoff, P.E., president, Wulfinghoff Energy Services Inc., discussed “Energy Payback Analysis: The First Test for a Sustainable Energy Future.”
“We need to substantially change the way we approach energy if we’re going to avoid a huge energy crash,” said Wulfinghoff.
A large number of energy efficiency projects fail, he said. A prime reason is “irresponsible project selection.” The participants did not look globally at all of the advantages and disadvantages.
Energy payback analysis is the “make-or-break criterion,” Wulfinghoff stated. Unfortunately, it is generally not applied. He defines it as the amount of energy input (the total amount of energy expended to create the project) versus the amount of energy output. It is determined solely by the laws of nature.
Financial payback varies with non-energy factors. He said you need to look at both energy payback and financial payback.
According to Wulfinghoff, a 10 MW solar application with a typical 20-year projected life will never achieve payback. This is because only a small fraction of the actual input energy is being counted for such renewable energy projects, which distorts the payback.
Shobin Uralil, founder and CFO of kWhOURS Inc., highlighted “Using iPads and Tablets for Energy Auditing and Facility Energy Management.”
Uralil noted that his company has developed an app that helps building professionals collect, manage, and share energy usage information and other building data. Large retrofit projects involve time in the field by a lot of people and the projects can take quite some time to complete. Data is scattered, including asset locations, specifications, site photos, etc.
In his firm’s app, once you collect your building information on your tablet, you send all your data to the cloud. The merged project data in the cloud can be accessed by computer for analysis. Proposed changes and project updates can then be sent back to an individual’s tablet via the cloud.
“Why do it on tablets? Because that’s where technology is heading,” said Uralil.
It provides fast data capture, reduces human error, results in less change orders, and minimizes disruption when there is staff turnover, he said.
Retro-commissioning, Continuous Commissioning
The life cycle building commissioning track began with a presentation by Bob West, P.E., vice president of operations, Advantage Research Monitoring Inc., called “Retro-Commissioning for Energy Efficiency.”
West said retro-commissioning is the commissioning of a building that has already been built but was never commissioned. “The purpose is to systematically optimize the building.”
You document baseline operation, analyze the current use, identify and verify operational and maintenance enhancements, and help train building personnel to maintain performance. “Energy efficiency is all about matching energy supply to demand,” he said. “You want to minimize energy waste.”
In performing retro-commissioning, you look at direct factors, which include chillers, motors, and lighting, and indirect factors, which include the building envelope and outside air.
In the planning phase, you review existing building documents, understand current building use, and develop a retro-commissioning plan. In the investigation phase, you perform a site assessment, analyze the building management system and controls, and come up with a list of deficiencies and potential improvements. In the implementation phase, you assist with implementation of improvements, retest affected equipment, and assist in training building personnel in proper operation and maintenance.
Finally, in the turnover phase, you prepare and submit a final report, and “perform seasonal checks to make sure the building continues to operate as intended,” said West.
Mike English, P.E., senior partner, Horizon Engineering Associates LLP, talked about “Barriers to Energy Efficiency and Overcoming Them: Lessons Learned from Retro-Commissioning.”
“Buildings consume 36 percent of total energy,” said English. The majority of buildings are 20-, 30-, or even 40-years- old. And those buildings weren’t commissioned back when they were constructed.
“What have we done to update our buildings? The general consensus is we really haven’t done anything,” he said.
Facility managers are too busy. Their feeling is that they “need to keep the walls up.” They need to keep the building operating.
There is no incentive for the landlord to put money into the building. Capital costs are high and it’s tough to get financing.
The basic way to be energy efficient is to do an energy audit. Digging deeper, you need to do retro-commissioning. You focus on building operations and match performance to requirements. “The best energy efficiency is to turn it off,” said English. Don’t run equipment when you don’t need it. Typically, you can get a 10- to 30-percent reduction with little or no capital investment by focusing on matching current need to current operations, he said.
Start by interviewing operations staff and building occupants on facility needs. Then come up with a master list of findings.
Because controls go out of calibration, you must continue monitoring the building to stay on track and keep the building at peak performance.
Jay Enck, chief technology officer, Commissioning & Green Building Solutions Inc., then had the perfect segue as he addressed “Monitoring-Based Commissioning: An Ongoing Process for Excellence.”
Owners and building operators aren’t getting feedback on what’s happening in their buildings, said Enck. If you don’t know the setup of the controls and the set points, then you don’t know if the current condition and design condition are matching.
With monitoring-based commissioning, you establish facility requirements and you begin collection of “big data,” which can be millions of pieces per day. You identify and correct performance issues. And you verify those corrections.
Without ongoing monitoring, building operators are in a firefighting mode. Controls may be overridden. Set points are incorrect.
To implement monitoring-based commissioning, you can get the information you need from the building automation system. You benchmark performance, Enck said, and then “the continuous feedback loop provides the information you need so you can make the best use of resources.”
Publication date: 12/24/2012