Optimizing HVAC Systems to Improve Energy Efficiency

Real-time, continuous optimization of holistic systems improves energy efficiency and performance at manufacturing plants and laboratories.
Sep 02, 2016

Heating, ventilation, and air conditioning (HVAC) systems—the chilled water plant, steam and hot water plant, and air distribution—consume 65% of the energy used in pharmaceutical manufacturing facilities, according to research by Lawrence Berkeley National Laboratory (1). Chilled water systems also consume substantial amounts of water. Optimizing these systems can contribute significantly to carbon dioxide (CO2) reduction and other corporate sustainability goals, as well as reduce manufacturing costs.

Although optimizing HVAC systems is an opportunity to improve efficiency, typical concerns include the possibility that implementation will result in loss of product, the need to meet quality assurance (QA) standards, and site finance requirements. It is possible to overcome all these hurdles, however, with effective project management and an engineered software solution that addresses HVAC in a holistic manner to get maximum benefits.

Optimization guidelines
A typical pharmaceutical facility tends to have strict requirements for 100% reliability; however, even new, state-of-the-art HVAC systems can lose operational efficiency. Compromising on product quality is not an option, so system operators take charge, overriding set points and placing HVAC systems in manual control to maintain system resiliency. As a result, efficiency suffers.

The goal of optimization is to make mechanical systems work at peak effectiveness, all the time. Pharma facility directors can optimize even the most demanding environments, with new or existing equipment, by employing a combination of engineering expertise, relational control software, and an ongoing technical support platform that keeps systems at commissioned levels.

The most successful optimization projects follow these three guidelines:

  • What cannot be measured cannot be optimized. Without an accurate measure of energy use by each piece of equipment in the system, it is impossible to accurately predict and report the impact of varying conditions on the system.
  • Optimize systems, not just individual components. If an optimization plan focuses only on installing the most efficient pieces of equipment without considering how to maximize performance of the whole system, it won’t capture the total available system efficiency. Holistic automatic optimization of HVAC systems typically increases energy efficiency by an additional 10 to 25% over just installing new equipment.
  • Optimization must be automatic, dynamic, and continuous for maximum efficiency. Optimization should be a real-time dynamic process, not a static set-and-forget process. If a plant’s operational control is not based on real-time inputs, it cannot be fully optimized.

The basic optimization process starts with calculating the current performance of the HVAC system to determine the potential energy savings. A detailed engineering analysis can show an hour-by-hour simulation of the system baseline performance against weather data and load profiles for a full year. Next, a scope-of-work document details the electrical, mechanical, and control upgrades required for a holistic optimization program. With that in hand, the engineering team can create a second model that simulates the system’s performance after the modifications are implemented and defines the delta between baseline and post-implementation performance to determine the energy and cost savings for the optimization project.

Finally, a lifecycle cost analysis should take into account the full implementation costs (mechanical, electrical, controls, optimization, project management, qualification, sales taxes, affiliate staff fees, information technology costs, permits, commissioning, engineering, contingency, and so on), the cost of money, depreciation, utility incentives, corporate taxes, and maintenance to calculate the project’s internal rate of return (IRR) and net present value.  Site stakeholders can then use this data to present the business case for the project.

Typical optimization projects implement a combination of the following energy conservation measures (ECMs).

  • Match the system to actual space user requirements, ensuring proper temperature and relative humidity set points, air-change-per-hour requirements, and space pressurization.
  • Install instrumentation (e.g., flow meters, power meters, temperature, and relative humidity sensors) to enable real-time control decisions, reporting on key performance indicators (KPIs), and measurement and verification. 
  • Install variable frequency drives on air-handling unit (AHU) fans, chillers, boiler combustion fans, chilled and hot water pumps, condenser water pumps, and cooling tower fans.
  • Provide fresh-air pre-cooling coils for cleanrooms.
  • Install modern AHU, chiller, and boiler controls.
  • Eliminate bottlenecks (e.g., hot or rogue zones, undersized terminal units) and mixing by replacing three-way temperature control valves with two-way control valves and closing decouplers.
  • Work with the QA group to provide all testing and commissioning reports required for GMP systems.

Once the ECMs are implemented, a real-time optimization program supported by optimization software can operate the system for both cost efficiency and energy efficiency. For example, intelligently resetting the supply air temperature on the clean room AHU will reduce simultaneous heating and cooling while allowing the system to reset chilled water and hot water temperatures back at the utility plant. An automated system can also control condenser water pumps, cooling towers, and chillers based on their relationship to one another. The end result is an opportunity to reduce the facility’s energy bills by over 20%, in the author’s experience. 

Case study
Johnson & Johnson’s HVAC efficiency programs, which were assisted by Optimum Energy, illustrate what’s possible. The company’s La Jolla, California research facility completed projects in 2014 that reduced CO2 emissions by 27%, electricity use by 28%, natural gas use by 19%, and water use by 12% over 2010 consumption (2).

Another J&J facility, the Ethicon manufacturing subsidiary, won the 2016 International Society for Pharmaceutical Engineering Facility of the Year award in the sustainability category for its Project COLD chiller optimization program (2). 

At Ethicon's 147,000-ft2 manufacturing facility, built in 1988, the optimization project reduced energy use by 26% (4.4 million kWh) and water use by 9% (1.25 million gallons) compared with 2010 consumption levels—while production volume increased by 11%, as the ISPE award noted (3). The project was financed by J&J’s CO2 Fund, which provides $40 million per year in capital relief to business units that implement CO2 reduction initiatives, and had an IRR of 30%. To further reduce energy consumption, Ethicon recently completed a Project n-AIR-g upgrade of its HVAC controls.

Ongoing optimization
Optimization is an ongoing process, and should include measurement, verification, and monitoring. Software can be used to track system key performance indicators and verify project savings. Due to facility staff outsourcing, staff reductions, and operational prioritization, a technical engineering team of HVAC experts dedicated to supporting the onsite operations staff is also essential to ensure long-term successful outcomes.  This is sometimes called monitoring-based commissioning or continuous commissioning. A one-time commissioning event is not enough anymore. Commissioning should happen every day, all day to keep the system operating at peak performance all the time.

References

  1. C. Galitsky, et al., Ernest Orlando Lawrence Berkeley National Laboratory, “Energy Efficiency Improvement and Cost Saving Opportunities for Pharmaceutical Industry” (2008), www.energystar.gov/ia/business/industry/in_focus/Pharmaceutical_Energy_Guide.pdf, accessed Sept. 1, 2016.
  2. Johnson & Johnson, “2014 Citizenship & Sustainability Report,” www.jnj.com/sites/default/files/pdf/cs/2014-JNJ-Citizenship-Sustainability-Report.pdf, accessed Sept. 1, 2016.
  3. ISPE. “2016 Facility of the Year Awards Category Winner for Sustainability,” www.facilityoftheyear.org/winners/2016-sustainability , accessed Sept. 1, 2016.

 

About the Author
Ben Erpelding, P.E., is chief technology officer at Optimum Energy; tel: 619.417.9984, [email protected]. Follow Optimum Energy on Twitter at @TrueOptimize

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