Category: Chilled Water

Replacing v. Upgrading Your BAS Network

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To replace or not to replace…

Wondering whether it’s more practical to replace your existing building automation system or to upgrade it? Consider three major points in favor of biting the bullet and replacing your BAS.

  1.  Moore’s Law: Holding on to your old system may limit its ability to perform.  New systems have expanded capacity, capability and can streamline data readings from multiple interfaces into a single, comprehensive system. Wireless technology has helped to reduce installation costs while increasing system flexibility. New systems are often less expensive than their dated counterparts once were and much more user friendly.
  2.  In-house Integration: Depending on the life of your other functioning equipment, replacing your BAS with a newer system may allow a more robust interaction among instruments. Upgrading an existing system may bring system features and facility needs into closer alignment, but will never be as close as that of a complete replacement.
  3.  All Good Things Come to an End: Eventually, your BAS will become obsolete-the trick is to determine whether it already is. Evaluate whether the system has some life left or whether it’s best to reset the clock now before the compatibility window has been shut.

    tekWorx CEO® can optimize your chiller plant by either becoming your plant’s brand new BAS, or by simply acting in a supervisory manner to coach your existing system to operate more efficiently.

Automotive Leader Reduces Energy Costs

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In January, the Chrysler Technical Center Facilities Group received a $200,000 DTE Energy rebate check for reducing their central energy plants annual energy costs by approximately $1 million! The DTE “Energy Efficiency Program for Business” incentive provides rebates to DTE Energy’s electric commercial customers for retrofitting facilities with more energy-efficient equipment for HVAC systems or control operations. These customer incentives are rewarded to customers based on the first year of energy savings in kWh with $200,000 being the maximum rebate given out.

The Chrysler Technical Center is one of the largest facilities under one roof in the world and, at a staggering 17,000 tons, also holds one of the largest chilled water systems. The Chilled Water System Optimization Project’s primary objective was simple: reduce the annual 49 million kWh and the associated $3.9 million price tag while automating the previously manual system. A reduction of 12 million kWh/year in cooling hours, or roughly $1 million per year, was achieved utilizing a variable flow strategy that entailed the integration of modern PLCs, VFDs, a variety of DP sensors, water pump impeller trimming, and a proprietary control algorithm developed by tekWorx.

Congratulations to the CTC facilities group on their incredible achievement! For more information regarding tekWorx chiller plant optimization capabilities, check out Our Approach.

Direct Control and Supervisory Control

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“Plant modifications”, “updates” and “conversions” are phrases that often make plant personnel nervous. Which modifications will bring about the greatest and longest lasting results? What do I have to give up to get the latest and greatest? How much is this going to disrupt the plant and my day-to-day? Will this really save energy?

tekWorx gets it. Working with complex systems that demand different automation techniques and design depending on client’s budgets, time frames, and permitted levels of disruption, tekWorx has seen it all and has you covered. Whether the system needs to be converted from manual operation to automated control or sequence updates need to be implemented for energy efficiency gains, tekWorx CEO® uses custom algorithms to improve any chilled plant’s operations.

In a world with emphasis on short paybacks, shrinking budgets, and long term environmental impacts, tekWorx engineers are practical and pragmatic experts and ensuring clients invest only in what they really need- both in engineering and equipment. As such, there are two overarching approaches in which tekWorx retrofits chilled water plants with its PLC based CEO® system.

When working with a plant that has no Building Automation System (BAS) or has a control system that is too outdated to produce the desired efficiency gains, tekWorx CEO® acts as a BAS for the entire chilled water plant; this is known as the Direct Control Engine. The CEO® then orchestrates all cooling related components (pumps, fans, cooling towers, valves, etc.), ensuring that the best combination of system components are being used to minimize kW per ton.

The second optimization approach is the Supervisory Control configuration, common when the existing BAS system (SCI, Siemens, ALC, etc.) is in good shape. In this set up, the CEO® and BAS coordinate over the plant’s BAS network to control and optimize the plant, sending real time data back and forth to ensure components are operating at maximum efficiency.

In either configuration, tekWorx uses a model to begin, but builds on that by using adaptive control algorithms that make adjustments based on actual system conditions to truly optimize chilled water production.

To find out more information on tekWorx CEO® and adaptive control for energy efficiency, fill out our Chiller Plant Evalution Form.

The Trouble with Temperature Control

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Delta, or ∆, is the word or symbol used to describe a difference between two related measurements. In the HVAC world, ∆ is used in reference to the difference between return and supply chilled water temperature. While the calculation to determine ∆ T is simple (T of return water less T of supply water), fluctuations in this number can have costly and complex repercussions in a chilled water plant.

Chiller plants are designed with the assumption that ∆ T will remain constant during the entire operating process. This ensures that the load is working efficiently to provide the necessary cooling requirements for the building or space. When the difference between return and supply water changes, the result can cause insufficient cooling loads. The common response to this condition is to bring on additional chillers in order to meet the load. As a result, there are circumstances where both pump energy and chiller energy unnecessarily increase to run two chillers. tekWorx hydronic and mechanical experts allows us to advise clients as to the most efficient chiller strategy. Depending on the facility, there are times when running two chillers is more efficient than one and vice versa. Further, tekWorx CEO® system unlocks the existing capacity in your plant so that you actually produce the cooling the chiller is designed to produce– that means you no longer have to bring on extra chillers before it’s time. For more information on how tekWorx can correct central plant ∆ T, check out Our Approach.

Energy Expenditures Add Up for Large Hospitals

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It should come as no surprise that hospitals are among the largest consumers of energy in the country. Operating continuously throughout the year with a large fluctuation of employees, patients, and visitors passing between rooms full of energy intensive medical equipment means energy costs add up quickly. The greatest operating expense lies in the sophisticated heating, ventilation, and air conditioning systems that control the temperatures and air flow throughout the buildings and in the temperature sensitive operating rooms. According to a 2007 study, there were approximately 3,040 large hospital buildings in the U.S. averaging 644,300 sq. ft., and requiring regular HVAC maintenance and scheduled repair. Of these, 612 utilized chilled water over forced air for their cooling needs. The total kWh for these facilities was a staggering 13 billion, or approximately 21,757 thousand kWh per building. At an average electricity rate of 79₵/ kWh, the energy expenditures per building were enormous. With seven years of inflation and rising energy costs, those numbers have only continued to grow.

At tekWorx, our approach to chiller plant optimization allows chiller plants at critical facilities like hospitals to lower unnecessary energy consumption up to 50% by ensuring each piece of equipment is running at its most efficient point. This significantly reduces operating bills at such client projects as Bayfront Medical Center and Jackson Memorial Hospital (Florida). Using an adaptive control system, tekWorx continuously monitors critical system parameters in real time and automatically adapts online operations. The result; a lot less kWh, lower maintenance and training costs, and better control of overall operating costs. For more information on tekWorx successes in chiller plant optimization check out our Solutions page.