Reducing the demand-side pull.
At Innovas Technologies, we spend considerable time evaluating the state of energy and how we can better provide products and services that benefit both our customers and the nationwide quality of life. Recently, the discussion veered into the subject of the “resiliency of the national power grid”.
With a massive refuel underway to power our electrical grid, the results have created a “hopefully transient” period where the resiliency of the grid might be tested in various regions of the country. The term “rolling blackouts” has entered the mainstream energy discussion in the United States for the first time in decades. Ultimately, this means it will become a priority for us all to reduce our electrical power consumption as much as possible to reduce the pressure on the electrical grid.
Focusing on chiller plant optimization.
When we focus the discussion towards chiller plant optimization and the power they draw from the grid, the opportunity for improving the power grid reliability gets interesting very quickly. Chillers can account for 50% of the total electricity consumption in commercial buildings during summer months, which means there is a growing responsibility for owners to improve cooling efficiency. With the majority of chillers suffering fouling-related efficiency loss, the opportunity can’t go unnoticed because there is a proven solution to eliminate it.
A more specific example might provide more clarity: Let’s look at a large midwestern University that delivers 45,000 refrigeration tons of cooling through its district cooling infrastructure in high-load conditions. In this case, let assume that fouling, left unchecked, causes a 10% reduction in chiller plant optimization. This results in 4,500 tons of cooling that is wasted. They consume electrical power and pay to produce it, but they don’t get to use it because it is lost to heat transfer inefficiency.
At peak demand times (summer) the university produces 45,000 tons and pulls 158MW from the grid. By eliminating chiller tube fouling, the University can reduce their electrical power demand by 10 to 15 megawatts. This is enough to power over 2,000 homes. When one extends the scenario nationally, improving chiller plant optimization reduces the draw on the grid by many, many thousands of megawatts.
Understanding the magnitude of U.S. Chiller demand on the electric grid.
In the U.S. the number of water-cooled chillers in operation is difficult to quantify and debated. Some chiller manufacturers estimate there are between 70,000 and 90,000 chillers in operation in the United States. So, for our purposes lets conservatively consider the number of chillers (Shell and Tube) to be 80,000. Water cooled chillers are quite efficient, but their efficiency is reduced due to fouling inside the heat transfer surfaces. Fouling in fact, is estimated to negatively impact 97% of all shell and tube chillers. From our learned experience, the fouling-related inefficiency is on average, at least 8%.
With 80,000 chillers operating we roughly estimate the average size of the chillers in order to obtain an ROM number of the total tonnage of US cooling during high demand periods when the grid is heavily taxed. For this exercise, we will assume the average size of all chillers (water) in the US to be 400 tons equaling total production of 32,000,000 tons of cooling. While this only an estimate, it demonstrates that the actual number is undoubtedly very big. At an 8% loss due to tube fouling, there are almost 3,000,000 tons of cooling that are wasted—representing a billion-dollar problem. Additionally, 3M tons of cooling can cool vast amounts of urban areas so its loss is expensive both in terms of grid output but also in simple financial terms.
Why the status quo is no longer sustainable.
The other side of this scenario is if the university continued with old, failed methods of tube fouling control. In this case, the opposite is true, and the university is pulling an 10 to 15 MW’s from the grid with no benefit. Not only does it cost the university huge & wasteful sums. It also weakens the grid’s ability to serve the larger economy. Unfortunately, this scenario is still the norm in many organizations.
In today’s environment, reducing the demand on the current grid is a growing priority in our overall national energy strategies. Reducing traditional energy consumption is important for all entities, and protecting the reliability of the grid for the whole nation is a shared responsibility. District energy plants or large chiller operators consume tremendous amounts of energy, so their work in optimizing chiller plant efficiency produces a significant contribution in this endeavor. By eliminating fouling using modern, proven automation, like the Helios Tube Cleaning System, the result is much-improved cost performance for the facility owner and industry, but also freeing up capacity on the national power grid to accept more energy demand related to new economic growth.