A high-speed centrifugal blower with high flow and high pressure output utilizing magnetic or airfoil bearings and integrated variable speed control.
Activated sludge wastewater treatment facilities consumed about 621 million kWh in the Pacific Northwest (2001 data, from NEEA's "Market Research Report: Pacific Northwest Water and Wastewater Market Assessment", Report #01-079, May, 2001). The aeration process can account for 25% to as much as 60% of total energy use at extended aeration wastewater treatment plants (WWTFs) using fine or ultra-fine bubble diffuser technology. The efficiency of turbo blowers is 70% to 80%, which is significantly higher than the 45% to 65% for positive displacement blowers and 50% to 70% for multi-stage centrifugals with either inlet throttling or variable speed controllers (From EPAs "Evaluation of Energy Conservation Measures", EPA 832-R-10-005, September, 2010). Assuming that blowers use about 50% of the energy at activated sludge plants and the efficiency of conventional blowers is 60%, potential energy savings are on the order of: 0.5 x 621 million kWh x (1- 0.60/0.75) = 62.1 million kWh/year.
Turbo blowers emerged in the North American market around 2007. Turbo blowers are now offered by K-Turbo, Neuros, Turblex, HSI, ABS Group, Atlas Copco, and Piller TSC. A 300 hp Neuros NX-300 turbo blower was installed at the Lakota WWTF in Federal Way, WA (the blower was partially paid for with a grant from PSE). This blower meets the plant aeration requirements without the need to run a 350 hp Roots positive displacement blower or two 250 hp Roots units.
Gearless high-speed turbo-blowers are a currently available retrofit technology for positive displacement blowers and multi-stage centrifugal blowers. The gearless turbo blowers are driven by high speed switched reluctance (SR) motors, are equipped with air or magnetic bearings, and have a turndown of 50% of rated flow. "Super Premium" efficiency SR motors must be used with a converter and thus inherently offer variable speed control. Nidec can supply SR motors up to 335 hp in either NEMA or IEC frames. The SR motor is compact, rugged, and can maintain high torque and efficiency over a broad speed range.
Missing is information about the reliability and maintenance requirements for turbo blowers.
Status:
Baseline Description: Baseline Energy Use: 310000000 kWh per year per unit
Activated sludge wastewater treatment facilities consumed about 621 million kWh in the Pacific Northwest (2001 data, from NEEA's "Market Research Report: Pacific Northwest Water and Wastewater Market Assessment", Report #01-079, May, 2001). The aeration process can account from 25% to as much as 60% of total energy use at extended aeration wastewater treatment plants (WWTFs) using fine or ultra-fine bubble diffuser technology. Assuming that conventional blowers used in aeration processes account for 50% of activated sludge WWTF annual energy use yields a total regional energy consumption of 310.5 million kWh/year.
"Typical" Savings: 20% Energy Savings Reliability: 4 - Extensive Assessment
The efficiency of turbo blowers is 70% to 80%, which is significantly higher than the 45% to 65% for positive displacement blowers and 50% to 70% for multi-stage centrifugals with either inlet throttling or variable speed controllers (From EPAs "Evaluation of Energy Conservation Measures", EPA 832-R-10-005, September, 2010). Assuming that the efficiency of conventional blowers is 60%, potential energy savings are equal to: (1- 0.60/0.75) x 100% = 20% of the baseline blower annual energy use.
Energy Use of an Emerging Technology is based upon the following algorithm. Baseline Energy Use - (Baseline Energy Use * Best Estimate of Energy Savings (either Typical savings OR the high range of savings.))
This analysis was set up using the total annual energy use for aeration processes in the region with the turboblowers expected to reduce this energy use by 20%. The "1" under units potentially replaced refers to the region's total aeration energy consumption.
Regional Technical Potential of an Emerging Technology is calculated as follows: Baseline Energy Use * Estimate of Energy Savings (either Typical savings OR the high range of savings) * Technical Potential (potential number of units replaced by the Emerging Technology)
Simple payback, new construction (years): N/A
Simple payback, retrofit (years): N/A
Cost Effectiveness is calculated using baseline energy use, best estimate of typical energy savings, and first cost. It does not account for factors such as impacts on O&M costs (which could be significant if product life is greatly extended) or savings of non-electric fuels such as natural gas. Actual overall cost effectiveness could be significantly different based on these other factors.
EPA, 10/05/2010. Evaluation of Energy Conservation Measures for Wastewater Treatment Facilities US Environmental Protection Agency
Quantum Consulting, Inc., 05/01/2001. Market Research Report: Pacific Northwest Water and Wastewater Market Assessment Quantum Consulting, Inc.