Chillin' Out With Energy Management
May 1, 2009
The fluctuating energy prices of the last year are just the latest incentives for making energy efficiency a high priority for any company that uses an industrial refrigeration system. By implementing an energy-management program such as EPA’s Energy Star for Industry; Focus on Energy’s Industrial Practical Energy Management and my organization’s Continuous Energy Improvement system, industrial processors can:
- Reduce energy costs.
- Reduce operations and maintenance costs.
- Improve productivity.
- Improve system reliability.
- Improve safety.
Companies realize the benefits of applying energy management to their refrigeration systems through a series of activities that, when combined, lead to continuous energy improvement. Among other things, activities should include assigning a refrigeration system champion, identifying and managing key performance indicators (KPIs) and conducting a comprehensive assessment that includes both the supply and demand sides of the system.
Assigning a Refrigeration System ChampionA refrigeration system champion ensures that the design, operation and maintenance of the refrigeration system are optimized to match the production, safety, energy and/or any other business objectives of the company. For example, the refrigeration champion can identify ways in which operation and maintenance practices can be enhanced to contribute to the optimal long-term performance of the refrigeration system.
The refrigeration system champion also minimizes lifecycle cost and maximizes the business objectives through an understanding of the proper design, use, operation and maintenance of the refrigeration system. This person should understand the details associated with the supply and demand sides of the refrigeration system, and use his or her knowledge to implement design, operation, maintenance and commissioning requirements in the safest, most cost-effective way possible.
Working with management to establish, track and manage the system to meet KPIs, communicating performance (energy, productivity and safety) issues and recommending necessary changes to the refrigeration system management team are other key duties of the refrigeration system champion.
Through these responsibilities, a refrigeration system champion can help ensure bottom line results. Consider a typical example: Reducing power demands by 135 hp (100 kW) in a process that runs continuously can deliver an energy cost reduction of at least $40,000 per year (assuming an energy price of $0.05/kWh). Benefits often are doubled when maintenance savings are included.
Plants with industrial ammonia refrigeration systems often can save up to 30 percent of electric energy use by focusing on improving system efficiency. In addition, other cost savings can be obtained through resulting non-energy benefits, including increased system safety, reduced maintenance and improved production.
Identifying and Managing KPIsKey performance indicators for the supply and demand sides of refrigeration systems play a crucial role in ensuring optimal performance. For example, refrigeration systems often are benchmarked on power required (kW) to produce a ton of refrigeration (TR), referred to as kW/TR. Minimizing refrigeration system kW/TR is an important goal for improving refrigeration system efficiency. Demand-side benchmarks include kWh per product unit and kWh/cubic/foot/month. With both supply- and demand-side metrics in place, refrigeration champions have the data required to ensure refrigeration systems run at optimal efficiency as well as those needed to establish and meet energy intensity goals.
Comprehensive Assessment. Energy is the single largest cost of ownership of an industrial refrigeration system, so it wise to evaluate the lifecycle cost of an existing installation before commissioning new equipment or carrying out a major overhaul. Lifecycle costing helps identify the lowest total-cost-of-ownership options available. The refrigeration champion should use lifecycle cost analysis to evaluate elements such as:
- Initial costs.
- Installation and commissioning costs.
- Energy costs.
- Operation costs.
- Maintenance and repair costs.
- Downtime costs.
- Environmental costs.
- Decommissioning and disposal costs.
- Operations and maintenance personnel interviews.
- System design and operation analysis relative to process requirements.
- Equipment performance evaluation.
- Energy consumption data.
- Control strategies and algorithms.
- System demand vs. capacity.
- Improving compressor, condenser and evaporator part load efficiency. These objectives often are accomplished through the application of variable frequency drives (VFDs).
- Lowering system discharge pressure.
- Upgrading equipment.
- Improving system design.
- Reducing refrigeration loads.
- Improving control capabilities.
For these reasons, it is important to establish an energy management program at your company, assign a refrigeration champion who has the training and authority to manage refrigeration system KPIs, and help management make good system decisions.
Keep in mind that qualified personnel, vendors, contractors and engineering firms that have the capability to assess your refrigeration system and make improvement recommendations should be engaged in the process. Contacting local utility representatives regarding energy management programs, incentives, and rebates also is helpful.