Trimmed Impeller Saves Brewery Almost $20,000 a Year

By understanding and modeling their cooling system with a simulation software tool, a national brewery was able to save $19,000 annually with a $1,500 investment, which consisted primarily of labor. This software tool provides value across multiple disciplines, industries and during all stages in the lifetime of a fluid piping system. It can help in the design, commissioning, operation and modification of fluid piping systems.

Simulation Software in Breweries

In the brewing industry, products are made in a variety of ways, in batches that are seasonal or under a continuous process. The software can simulate either type of system along with the required support service to ensure that food safety and environmental standards are met. In addition, the design engineers can simulate the various processes. By having a clear view of the entire plant’s operation, engineers can optimize each operation to minimize energy usage by fine tuning the system according to the current needs. Also, the ability to store each operations model and adjust for different plant demands allows plant managers to plan and schedule resources to further reduce operating costs and increase profitability.

Original System Issues

The brewery analyzed their glycol circulation system used for batch cooling of beer products at one of its brewing facilities. In beer production, the product is cooled first in a heat exchanger and then in storage tanks after the process is complete. The original system consisted of three parallel pumps driven by 110 kilowatt (kW) electric motors, impeller diameters of 430 millimeters (mm), and about 100 meters (m) of total head. Because the pumps were oversized, a control valve on the pump discharge was throttled, resulting in significant head loss. In a previous effort to improve system efficiency, one pump’s impeller had been trimmed to 375 mm diameter and its motor was replaced with a 55 kW unit. But, at flow rates above 65 liters per second (l/s), the motor would overload. This pump was placed out of service and the system ran with one continuously operating 110 kW pump.

Considerations

To improve energy efficiency and performance of the beer cooling system, three options were considered: trimming the pump impeller, installing a new pump that matched the existing system and installing a new pump with a variable speed drive.

Results

A single change was made by trimming one pump impeller to 300 mm. This allowed the pump to operate more efficiently while minimizing losses in the control valve. Electric consumption of the cooling system was reduced by more than 50 percent from 981,000 kilowatt hours (kWh) to 473,000 kWh. Also, energy costs dropped from $36,700 to $17,700 annually.