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By Carl C. Schultz, Chief Mechanical Engineer, URS Corporation (Columbus, Ohio)
I used to think that the terms re-commissioning and retro-commissioning meant roughly the same thing. But then I realized that they are not. The term re-commissioning refers to the commissioning of buildings that have previously been commissioned, while retro-commissioning is used to describe the commissioning of systems that have not been commissioned before. Both options present great opportunities for the development and expansion of the building commissioning and commissioning business.
With energy costs rising, selling such services should be easy. A 2004 study of 224 new and existing buildings by researchers at Lawrence Berkeley National Laboratory found that commissioning existing buildings was more cost-effective than commissioning new ones. The study recommended that commissioning existing buildings should focus more on reducing energy consumption, while commissioning new buildings should consider a broader range of goals: providing thermal comfort, improving and maintaining indoor air quality, and improving the overall efficiency of building utilities.
The average commissioning and start-up cost for existing buildings is $0.27/ft2 (0.0929 m2) with a 15% reduction in energy consumption, with a payback period of 0.7 years. For new buildings, the average commissioning and start-up cost is $1.00/ft2 with a payback period of 4.8 years. I believe building owners are interested in projects that can pay for themselves in 18 months or less, so a recommissioning and start-up is an attractive proposition.
If you are a commissioning agent for an engineering consulting firm, your biggest competitors may be organizations that specialize in testing, tuning and balancing (TAB) equipment. They naturally occupy and hold this market segment. Other companies that specialize in consulting services often have to hire outside specialists for balancing by measuring ventilation and water supply systems, checking and adjusting flow rates, and for work related to temperature control.
TAB specialists will likely have a competitive advantage over you, especially if they performed the initial rebalancing of the systems in such buildings, and especially if they have continued to maintain and modify those systems. Over time, complex mechanical systems wear out and become less well maintained, which leads to a decrease in their performance. If HVAC systems begin to perform poorly, building owners will likely turn to the original TAB specialists. They can easily convince owners that a complete rebuild is needed rather than a thorough rebalancing of the systems in question.
But commissioning agents working for consulting engineering firms should not be disappointed — they have a number of distinct advantages. For example, their firm could design the mechanical and electrical systems for the building in question, could be involved in assessing the condition of the building or in studies that helped decide whether to upgrade existing systems. Again, engineers are better able to carry out the necessary calculations and analyses needed to determine the objectives of the projects being prepared. They can provide more comprehensive information and more convincing arguments. Consulting engineers can be more independent and impartial.
In any case, after concluding a contract for the performance of work of any type, the agent must get down to business.
Preparation
After the building inspection, both recommissioning and recommissioning should include interviews with those responsible for building maintenance and reviewing utility bills for the past few years. Many of the tasks required in the early stages are similar to those associated with energy management, such as identifying measures to reduce energy consumption. The main difference is that commissioning typically does not include capital-intensive projects. Instead of creating new processes and systems, it should focus on optimizing the operation of existing systems and maintaining them. Capital-intensive projects are left to companies that specialize in energy supply and maintenance.
For these specialized services, some customers are more challenging than others. It is better if energy consumption is high and the mechanical and electrical systems support critical components. Examples of such buildings include hospitals, laboratories, data centers, and pharmaceutical facilities. Recently, laboratories have become a major area for energy reduction efforts. The U.S. Environmental Protection Agency and the U.S. Department of Energy have created Labs21, an organization aimed at improving the energy efficiency and environmental safety of laboratories. The American Society for Healthcare Engineering (ASHE) recently completed a project that resulted in the Healthcare Energy Guidebook, a document that provides information on benchmarks needed to compare the relative energy efficiencies of health care facilities. The American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) has worked in these areas before, creating technical committees to develop energy consumption standards for medical equipment and to test some of the older assumptions underlying the commonly used air change rates for laboratory building ventilation systems.
But there is still a lot of work to be done to standardize this data. Much of the information is still unstandardized (costs per ft2) for specific user groups and climate zones. But you can take advantage of the growing body of knowledge. With the right information, you can develop amazing energy reduction scenarios that will capture your customers' imaginations. And that will help you convince them of the benefits of both recommissioning and recommissioning.
How to Convince the Customer
Many laboratories deliberately overstate the air exchange rate, and in vivariums it is increased significantly. Using ventilation systems 24 hours a day all year round results in high energy consumption. In many cases, such increases in air exchange rate are clearly excessive, which gives you the opportunity to offer your clients a survey to determine whether it is possible to reduce the air exchange rate in lab spaces that are not used very intensively.
Future changes in the use of laboratory space may result in the building owner calling you back to design and implement appropriate changes to the ventilation systems. An investigation may reveal that the air change rate is not decreasing at night. Appropriate changes to the program that controls the ventilation systems and minor adjustments to the air change balance can save significant money. Hospitals also have laboratory space, and real savings can be achieved by adjusting the ventilation systems in operating rooms and diagnostic rooms, where good ventilation is needed and the temperature is often set very low. The air change rate in these rooms can be adjusted according to a set schedule, but provided that the required pressure difference can be maintained. The air temperature in these rooms can be increased at night.
Another common occurrence during return commissioning is the simultaneous overuse of heating and cooling. This problem is also related to the above examples of over-ventilation. The air temperature in the ventilation system also has to be adjusted to the required values. During non-working hours, lighting systems are either switched off or operate partially, and other equipment that generates excess heat is usually switched off, which leads to increased energy costs for air heating.
Examples of the simultaneous use of heating and cooling are common in modern laboratories, which are designed in a modular manner to increase the flexibility of their use. The installation and removal of walls allows the rapid creation of laboratory rooms of the desired size by combining or separating modules. Each laboratory module has its own thermostat, and when several modules are combined into one room, the settings of these thermostats may not match each other. However, by equalizing the settings or by temporarily turning off redundant thermostats, significant energy savings can be achieved. Simultaneous heating and cooling of the air in the rooms can be compared to driving a car with both the gas and brake pedals pressed simultaneously. In other types of buildings, energy losses due to “thermostat competition” may be reduced by the use of ventilation systems using recirculated air, but in laboratory buildings this type of ventilation is rarely used, and usually all the air is drawn into the ventilation system from outside. In addition, the ventilation systems in laboratory rooms operate 24 hours a day. The operating and maintenance costs of such systems in laboratory buildings are significantly higher due to higher energy consumption and the greater number and complexity of subsystems involved. And simple adjustment of the system operation in this case can help to save significant funds.
Reverse commissioning can also help reduce costs by scheduling the systems on an hourly basis. This is true not only for central air conditioning systems in buildings, but also for smaller systems such as simple exhaust fans. My company recently completed work at a cancer center where we discovered that the humidity levels in the center were too high. It turned out that the exhaust fans were not being turned off during off-hours. Since the air conditioning systems were turned off during these off-hours, this allowed warm, moist outside air to infiltrate the space. By scheduling the exhaust fans to turn on and off in parallel with the air conditioning systems, the excess humidity problem was eliminated and the building owner could reduce future HVAC operating costs.Excessive use of hot and cold water in room temperature control systems is common in buildings with low temperature differences. If the pumps' output pressure is high, the system may have oversized distribution pumps, causing the control valves to malfunction because they cannot close completely.
Sometimes you come across paradoxical situations. A pharmaceutical company had a low temperature difference between the water entering and leaving the heating system for many years (4 to 8 degrees). Usually it is 20 to 25 degrees. It turned out that there was an open 8-inch shunt in the system and a large amount of hot water was bypassing the heating equipment. Not surprisingly, the system had a very low pressure difference between the supply and return lines. When hot water heating and cooling systems are not working properly, reducing the drive speed (if there is a variable speed drive, of course) may seem like a good idea. But a more correct solution is to regulate the pump impeller performance when the drive is operating at maximum speed for the pump. This will allow the drive to modulate the system at reduced loads, optimizing its operation.
Forging Alliances
The examples above highlight the need for alliances with temperature control companies and TAB professionals. Care must be taken when defining the scope of work when developing recommissioning and return commissioning projects, which should include the cost of such work.
While commissioning agents with engineering experience can excel in this area, they face stiff competition from temperature control and TAB specialists. However, you can also partner with these specialists.
Commissioning Tools
Charles Brown, owner of Mobile Robotics, has been in the pipe inspection business for over 15 years. When a major Boston hospital asked him to trace the plumbing lines for an expansion, he decided to use traditional pipe locating equipment, which is sometimes inaccurate. Plus, the hospital didn't have plans for its plumbing system, making the task more difficult.
It took Brown a whole day to track a 50-meter section of pipes. He used a regular geolocator. Most of the time, the same thing happened: a signal would appear on the locator and disappear after a few seconds. Brown would go back a few steps, and the signal would appear again. This process was very time-consuming, and he began to doubt the value and accuracy of the information he was receiving. Brown could not determine exactly what was causing the problem. Perhaps the magnetic field of the hospital CT scanners was interfering with the operation of the geolocator probe.
After that, Brown learned that there was new equipment designed to be used in difficult cases when it was necessary to determine the position of a camera and a remote transmitter (probe). He used this device. And no matter what position he held it in, it quickly led him to the target, determined by the signal amplification. Brown was also attracted by the possibility of zeros and false peaks that made it difficult to detect utilities using regular geolocators. The device was equipped with probes using four different signal frequencies, which made it possible to find any cameras and remote transmitters. In addition, it can be used to track three-phase frequencies and disconnected AC lines. The user reads these frequencies from a digital indicator equipped with a display with a mini-map displayed on it.
(Based on materials from Consulting-Specifying Engineer magazine) |
