We all have a responsibility to treat water as a precious and diminishing resource. However, aside from not taking long showers or replacing toilets with low-flow ones, not many plausible solutions are widely known. When looking at commercial and industrial buildings, though, a new arena for efficiency quickly becomes obvious.
Typically, the HVAC system uses the most water and energy in these buildings. In most commercial buildings, the system also represents the highest operating and capital expense. The 500,000 operational cooling towers in the U.S. use approximately 5 trillion gallons of potable water each year combined. This amount could fill the Rose Bowl 60,000 times or occupy nearly a quarter of the Chesapeake Bay’s 18 trillion gallons of water.
Additionally, water quality is a vicious variable in cooling water systems. Water is safe, easy-to-handle, widely accessible and relatively inexpensive in most industrialized regions of the world. It’s also an efficient heat transfer medium, better than many other materials.
What most people don’t realize is the variability of the water quality can present potential for major issues in systems due to scale, corrosion and fouling. These factors can also have a direct effect on equipment life. As water concentrates in cooling systems, dissolved ions can exceed the solubility of some minerals and form scale.
Water and energy use are closely related. On average, a neglected or poorly maintained cooling tower can reduce chiller efficiency by 10 to 35 percent. A .25-inch of scale in a heat exchanger could increase energy consumption by up to 40 percent. Process or cooling equipment components can also fail at the most inopportune moment.
The solution
Until now, the industry has focused on energy usage, but it’s important to realize energy and water are interdependent. The water-energy nexus plainly illustrates that it takes energy to move water and water to make energy.
A technology that addresses water efficiency and water quality with useful data and heat or exchange or energy efficiency has never existed. In fact, these two previously disparate data silos were only combined by hand.
What is going on
Ideally, the energy management system (EMS) should be integrated with water treatment management systems. Both are directly related to efficient energy exchanges.
However, the chiller panel does not communicate with the water treatment controller, which is typically monitored by monthly, in-person check ups. Not only does aggregating and analyzing the heat exchange and water quality data take time, but it also requires human labor. Regardless, doing the math and chemistry by hand isn’t reliable because it does not pull the data continuously.
A technology is emerging to remedy this issue by aggregating and analyzing heat exchange and water quality data. It establishes relationships that have never before been evaluated, which minimizes the risk of shutdown and failure while optimizing efficiencies. Identifying the risks is integral to risk management.
A case study of a 1,000-ton chiller plant assumed a 10 percent decrease in energy efficiency. With an average annual electric utility cost of $127,500, the annual cost of wasted energy was $12,750. This was caused by a dirty heat exchanger that wasn’t properly monitored.
In 2007, a central energy plant (CEP) leadership team realized the importance of real-time water management early on in the commissioning phase on one of the country’s largest biotechnology campuses.
The facility relies heavily on the cooling system for its million-dollar labs and offices. During commissioning, construction-related debris was discovered in the extensive distribution piping system. The leadership team quickly identified that this situation would negatively impact its performance and drive up operating costs.
Working with the leadership, the technology was installed in the CEP, bridging the gap between the heat exchange and water treatment controller data sets.
The innovation is designed to continuously commission water quality, water usage and energy usage in near real time. It can be viewed at any time from a computer or mobile device – not just within the plant.
This new data reveals transparency of operating costs and water quality management because two formerly separate data sets communicate, setting a benchmark.
At the enterprise level, this technology provides operational and capital risk management of water systems and their associated energy usage.
At the facilities level, the value-added diagnostic tool optimizes water, energy, heat-exchange efficiency as well as water treatment chemistries for constant and unpredictable conditions. It can also help to improve public health and safety by monitoring biofouling, which can potentially lead to preventable Legionella.
Straight talk
All in all, this technology saves money. Downtime caused by Legionella, unscheduled maintenance, water, weather and human error as well as critical failures and inefficiencies are all drain funds. The real value in a benchmark and benchmarking tool gives the owner or facility manager the full transparency of what they are spending on water and energy. It also makes visible who or what is responsible for any inefficiencies and operating expenses.
Conclusion
It’s tough to manage what you can’t, or don’t, measure.
A maintenance or facility professional works to maintain an efficient and operational HVAC system while maintaining critical sustainability, so smart water and energy efficiency technologies must be implemented into commercial and industrial buildings.
While energy has always been the first to be monitored and optimized, water is also slowly diminishing, and focus must be given to the water side of the cooling system. Support for waterside optimization and conservation strategies is slowly becoming en vogue, but we must do more.
