Industrial process chillers use vapor-compression to remove heat from liquids, playing a crucial role in temperature control across many industries. Because chillers consume significant electrical power, understanding and optimizing their energy efficiency is essential to reduce operating costs and environmental impact.
There are Two Commonly Used Efficiency Ratios:
- Coefficient of Performance (COP) – COP is the ratio between the refrigeration capacity or heat removed in BTU/hour or watts and the electrical power input in BTU/hour or watts. Therefore, the COP has no dimension.
The higher the COP, the more efficient the system is.
- Energy Efficiency Ratio (EER) – EER is the ratio between the refrigeration capacity or heat removed in BTU/hour and the electric power input in watts. The units of measure of EER are BTU/W in an hour.
The higher the EER, the more efficient the system is.
Most companies publish their COP or EER at 100% load capacity of the chiller. Since a chiller does not always run at 100% capacity, this is not an ideal representation of the typical equipment performance because:
- The performance is calculated at a single operating point
- It doesn’t include how a chiller will perform during part-load conditions
- Equipment with an excellent full-load efficiency may have less than satisfactory part-load efficiency
Traditional temperature control equipment cycles heating or cooling output on and off in fixed steps, which works fine for loose tolerances but struggles the moment a process needs precision, speed, or both.
AHRI 550/590 Standard Definition
The Air-Conditioning, Heating and Refrigeration Institute (AHRI) has developed a standard (AHRI 550/590 Standard) that defines the Integrated Part Load Value (IPLV) as a better performance characteristic for chillers. Over the lifetime of a chiller, it is running at 100% capacity only 1% of the time, or in other words, 99% of the time it is at part-load conditions.
The IPLV is calculated using EER values at different operating loads:
- A = EER @ 100% Load
- B = EER @ 75% Load
- C = EER @ 50% Load
- D = EER @ 25% Load
The AHRI-standardized time distribution is:
- A = 1%
- B = 42%
- C = 45%
- D = 12%
LPVY= 1%*A + 42%*B + 45%*C + 12%*D
Why is IPLV Important?
The IPLV is a very important value to consider since it can affect energy usage and operating costs throughout the lifetime of the process chiller equipment. In fact, electrical consumption is the highest operating cost in almost all chiller-based cooling operations.
Delta T Systems’ chillers are engineered to achieve industry-leading IPLV ratings, thanks to advanced components like variable speed compressors, electronic expansion valves, and proprietary control algorithms.
Variable Speed Packaged Air-cooled (VSPA) Chiller Configurations – IPLV (in EER)
One Refrigeration Circuit
- VSPA 1 Ton: 20.9
- VSPA 2 Ton: 21.2
- VSPA 3 Ton: 19.6
- VSPA 4 Ton: 21.8
- VSPA 8 Ton: 21.5
- VSPA 10 Ton: 22.1
- VSPA 15 Ton: 24.0
Two Refrigeration Circuits
- VSPA 20 Ton: 22.1
- VSPA 25 Ton: 22.4
- VSPA 30 Ton: 24.0
Four Refrigeration Circuits
- VSPA 40 Ton: 22.1
- VSPA 50 Ton: 22.4
- VSPA 60 Ton: 24.0
In addition to many other industry-leading technologies, the IPLV ratings of Delta T Systems’ process chillers are between 40% and 60% higher than comparable products from our competition with IPLV ratings of approximately 15 (EER).
Translating High IPLV Ratings to Energy and Cost Savings with Delta T Systems’ Process Chiller Systems
For a 10-ton chiller, operating 16 hours a day (2 shifts), 5 days a week, 52 weeks a year, at 0.14 $/KW-hr, Delta T Systems estimates about $450 per IPLV(EER) point per year. A difference of 7 points in the IPLV rating could end up saving $3,150 in energy costs per year.

For an analysis of your industrial process chiller system’s energy efficiency, contact Delta T Systems today to speak to an Application Engineer. See how they can help you to save money and energy in your chiller system.
Delta T Systems is an industry-leading temperature control system manufacturer. All our products are designed and built in the USA. Our systems have been applied in a broad range of industries and applications, and our custom TCU and Chiller design group continues to evaluate new applications on an ongoing basis.
Our engineering capabilities have put our systems at the forefront of green temperature control technology by providing state-of-the-art controls and the lowest energy consumption available in the industry. Our commitment to sustainability, efficiency, and customer service is the reason clients continue to return to us time after time for new applications.
You can also learn more about Troubleshooting Common Issues with Industrial Chillers.