In cold-storage facilities, utility costs are a very significant expense. One refrigerated warehouse in Ohio started by upgrading their lights to LEDs with occupancy sensors. The next major system to consider was their 1,000 hp ammonia refrigeration system, which consists of multiple compressors, condensers, and evaporator fans and annually consumed over $400,000 in energy.
Due to the complexity of ammonia refrigerators systems, one must first understand the function it needs to perform, the equipment present, and how the equipment is controlled before making any modifications. We studied the system and set up a custom simulation to understand its operation. Our simulation and experience allowed us to identify eight low-cost opportunities that could combine to reduce the system’s energy use by around 15%. These opportunities were in evaporator set-point optimization, ensuring system components operate correctly, modifying pressure set-points, and controls sequencing. We also identified and analyzed the impact of two potential capital-upgrades opportunities for consideration.
The facility implemented the low-cost opportunities. According to analysis from the facility’s local utility energy efficiency program, they succeeded in reducing system energy use by 15%, closely matching the results of our simulation. Further, they were able to cover the cost of labor to implement the projects through utility incentives!
Energy auditor and technical advisor