Chilled water plants are one of the largest sources of HVAC cooling and process cooling in the US.
The demand for commercial and industrial cooling infrastructure is expected to grow in the coming years due to economic growth and the advent of advanced cooling technology replacing legacy systems. One of the influential drivers is the increasing popularity of chillers in district energy and chilled water plants. These types of plants provide highly efficient cooling (Compared to other cooling methods) to very large facility complexes, but they also use a large amount of electricity. According to the DOE, chillers in the US consume up to 50% of all electricity produced during the hottest summer months. As infrastructure and demand grows, the draw from the grid by chillers will be a growing factor that likely will receive public and political attention. The good news is that there are methods available to reduce the impact cooling plays in grid consumption and at the same time increase the amount of cooling needed for the nation. Another variable looms as electricity production plants repower, close or are replaced by alternative energy. The national grid will likely experience fragility during the transition requiring chilled water plant optimization.
Why is the U.S Electrical grid stressed?
The United States’ electrical grid is being transformed through the conversion of traditional generation methods with alternative Green-Energy systems. For example, traditional power generation is evolving through “refueling” from base fuels like coal to more environmentally friendly fuels like natural gas and biofuels. Also, many older plants are being shuttered early to prevent their contribution to carbon emissions released into the atmosphere. These factors coincide with a growing demand for electricity due to population growth and the expanding reliance on electricity in the US for EV’s—thus placing strain on the system and making it more likely to fail during peak periods. To make matters worse, the grid is likely becoming more vulnerable to extreme weather conditions, such as hurricanes, floods, and ice storms because clean energy generation systems (winds/solar) are more exposed to the weather as was the case of the Texas ice storm in 2021. Extraordinary weather events like these can damage alternative energy infrastructure and disrupt service for days or even weeks. The bottom line is that the U.S. electrical grid is evolving, and significant upgrades and innovation will be needed if it is to meet the expanding challenges of this century. Part of the innovation needed will have to come from users creatively reducing energy consumption from the grid.
Water cooled chiller plants provide great value, but also consume electrical power.
Water cooled chiller plants are considered the most efficient option to cool large buildings, industrial facilities and district energy building blocks. While water cooled chillers are very effective at providing cooling, they also consume large amounts of electricity and thus represent a prime opportunity for optimization. Specifically, a typical 2000-ton chiller operating at full load consumes 1.2MW’s of power to provide cooling. A larger chiller, say 5,000 tons, running at full load consumes roughly 3MW’s of electricity. Commonly, chillers operate at a level of 8 to 12% of reduced efficiency due to inside tube fouling. This translates to, in the 5000T chiller, 300 tons of cooling being lost and 180kW excess energy consumption due to fouling, all unnecessarily. When one considers there are well over 100,000 chillers operating in the US, the energy requirement to power them is vast. Due to their propensity for fouling caused inefficiency, the opportunity to eliminate unnecessary waste in chillers is also vast. The benefits of chiller fouling elimination are many including the tremendous pressure removed from the grid.
What can plant operators do to reduce energy consumption?
As the costs of energy continue to rise, many plant operators are looking for ways to reduce their consumption. There are numerous measures that can be taken to achieve this goal. One is to install energy-efficient motors and variable frequency drives. These components can help to optimize the use of electricity while also reducing wear and tear on equipment. Another is to implement demand-side management programs that help to reduce the overall demand for energy by altering production schedules, engaging in load shedding during peak periods and or chiller efficiency initiatives.
One of the most fundamental and effective ways to reduce chiller energy consumption is by taking steps to limit tube fouling when available. As stated, when tube fouling occurs in a water-cooled heat exchanger, it has a major impact on the efficiency of the device. Specifically, tube fouling is caused by the build-up of deposits on the inside surface of the tubes, which reduces the ability of heat to transfer back and forth from the hot fluid to the cold fluid. In addition, tube fouling also causes reduced flow rates and increased pressure drop across the heat exchanger. To control fouling, the century old status quo has been to conduct periodic manual cleaning. As the chart below shows, periodic manual cleaning results in clean tube efficiency for a very brief period, and then the fouling quickly reappe
ars and the chiller degrades in efficiency. Automatic tube cleaning systems, like the Helios Tube Cleaning System by Innovas Technologies, automatically eliminate fouling from occurring in the first place keeping the fouling related efficiency at 100%. The results are striking.
For perspective, consider the operation of 5, 2000 ton water cooled chillers running at peak load in the heat of the summer. These chillers would consume roughly 6 MW’s of power at peak load which is enough to power 6000 average homes. If the chillers are running somewhat less efficient due to tube fouling, say 10% reduced, then 600 Kw’s are being lost to inefficiency. 600Kwh’s can supply constant electricity to up to 600 homes. The impacts are significant, and luckily, easily prevented.
How does the Helios TCS work?
The Helios Automatic Tube Cleaning System® from Innovas Technologies eliminates tube fouling contributing to chilled water plant optimization. The system is proven, reliable and the install base has run millions of cycles without any process interruptions. It works by injecting cleaning balls into the entry point of heat exchanger tubes and collecting them in a trap on the exit part of the heat exchanger. The cleaning balls gently “wipe” the insides of the tubes clean, eliminating bio scale and preventing deposits from accumulating.
In multiple studies across more than a dozen installations the Helios TCS® has proven to reduce energy consumption by as much as 18 percent. In addition, by eliminating the regular maintenance required for heat exchanger cleaning it further supports operators with chilled water plant optimization. To learn more about how the Helios can help your organization visit www.innovastechnologies.com/products.
