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Save 80% in Maintenance Costs w/ Auto-Cleaning Water Filters for Healthcare Cooling Towers

Jun 5, 2018 8:05:15 PM

Case Study Autocleaning Cooling Tower Filtration CES Florida HVAC VAFVirtually every industrial or healthcare facility has a cooling tower.  Furthermore, statistics point to as much as 5% of municipal water is used each year in cooling tower makeup.   Automatic screen filters requires much less water than other self-cleaning filters that utilize backwash cycles (US DOE). 

CES utilizes V-Series state-of-the-art Automatic Cleaning Filtration Systems by VAF Filtration Systems.  The extensive features and conservation benefits of the VAF system provides the facility with clean cooling tower basins at a lower system cost, lower energy costs and saves 80% in maintenance expense.  See how it works in the video below.  To request a quote click here.

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Case Study Project (by VAF Filtration Systems):

A medical center made the determination that filtration was needed for their three 400 ton cooling towers for the following reasons:

  1. Fouling and corrosion issues at the chiller condenser water head
  2. 1” of fine silt and organics sediment accumulation in the basins every 6 months resulting in Legionella habitat buildup
  3. Cooling tower fill had to be replaced because of the fouling that had plugged the fill channels which resulted from the unfiltered cooling water


Originally the medical center had specified sand media filtration for their cooling tower system.  The objective was to clean the basins directly before any debris had a chance to enter the cooling system and to reduce the habitat for Legionella bacteria living in the deposits in the basin.  After reviewing the media system with the mechanical engineering firm assisting with the cooling tower renovation project, a decision was made to use automatic self-cleaning screen filtration technology for the following reasons:

  1. Limited space requirements. Media filtration systems would require one large media vessel per two cooling tower cells because of the back-flushing methods inherent with this technology.  Automatic screen filtration requires about half the footprint of media filtration for each tower.
  2. Unacceptable large amount of backflush water required by media filtration.  A fresh potable water supply, which had to be heat traced, was required to each vessel due to the backflushing methods inherent with this technology.  Each vessel had a filter rate of 57 m3/hr (251 gpm) and required a two minute 57 m3/hr (1,893 liters) or 251 gpm (500 gallons) backflush cycle for each backflush.  This large loss of potable backflush water required for backflushing was unacceptable.
  3. Excessive energy requirements required for the proposed media system.The media filtration system required a 7.5HP pump for each two vessel system resulting in 22.5HP pumps running 24 hours per day. This would have resulted in a significant increase in the medical center's annual energy expense estimated at $19,021 (assuming $0.11/kWh energy cost and best pump efficiency point of 85%).

After it was determined the media system was not a feasible solution, a screen filtration system was to be evaluated. 


Evoqua's VAF LCFX system was selected as the system of choice for the following reasons:

  1. Only one 10HP pump required to provide basin cleaning for the entire 1200 ton cooling tower
  2. 55% reduction in pump size required by reducing from 22.5HP to 10HP
  3. 70% reduction in filtration flow rate per tower basin from 159 m3/hr to 45 m3/hr (700 gpm to 200 gpm)
  4. 75% reduction in operating time from 24 hours per day to only 6 hours per day for all three towers resulting in total volume turned twice a day
  5. 87% reduction in energy cost (energy cost for the LCFX-500-10 was $2,426.82 using a 74% efficiency and $0.11/kWh)
  6. 95% reduction in flush waste compared to a single tower media filter system
  7. The footprint of the single LCFX system skid was 122 cm x 132 cm (48" x 52"), which was a much smaller footprint than for the two media systems option
  8. LCFX’s flexibility of basin cleaning times based on dirt load
  9. LCFX’s BACnet interface for remote monitoring and operation capabilities

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LCFX General Operation:

The LCFX system has unsurpassed conservation operating efficiencies over conventional cooling tower filtration systems while providing both basin agitation and cooling water cleaning.  By combining the patented V-SeriesTM filters and the reduction in energy usage and water saving components of the LCFX system, an ROI can be achieved in less than a year. 

In addition, this system will help eliminate the environment where Legionella and other bacteria can grow by keeping the basins clean from organics and light silt that provide the habitat and food source for bacteria to thrive.  Corrosion and fouling issues were also noticeably alleviated.

The zone control system maintains a pressurized mainline that has zone control valves placed at each defined zone.  Each zone has a specified number of eductor turbulator nozzles, placed inside the basin that agitates particulate and keeps it in suspension for removal by filtration.

The VFD/PLC control provides energy efficiency by operating the pump only at the minimum 1.4 bar (20 psi) required for the eductor nozzles’ basin agitation, and then provides the minimum of 2 bar (30 psi) required for the filter’s 30 second flush cycle, thus maintaining low energy usage for an extended time period.

For the medical center installation, the zone controller was initially programmed to monitor the cleaning of each tower for a minimum of two hours per tower per day.  This equated to a full turn of each basin volume twice a day in just six hours of operation.  The system then sleeps for the remaining 18 hours each day.

Controller Information:

MicroFlushTM Controller: The VAF MicroFlush (MF) Controller provides multiple advanced features that allow for the monitoring and control of a single filter or filtration system, not the least of which is the “failsafe” program to prevent cooling tower basin drainage and the ability to upgrade the controller to a SCADA interface with a simple plug-n-play “smart” module.  The MF can monitor a single filter or up to 4 filters in a system, when installed in parallel.  The MF controller monitors the filter(s) Pressure Differential (PD) and automatically initiates a flushing cycle when the PD reaches the preset 0.5 bar or 7 psi across the filter’s inlet/outlet.

The MF controller provides the ability for data logging so that accurate monitoring and historical data can be accessed by means of the MF display. The controller is housed in a weather resistant enclosure that is suitable for indoor or outdoor installation. The MF controller is offered with either

Battery, Solar, 120VAC or 220VAC power inputs to maximize installation flexibility at any location. The controller provides outputs to operate AC or DC solenoid diaphragm flush valves, electronically actuated ball flush valves or latching solenoids and provides terminal connections for “optional device” outputs, such as throttling valves or booster pumps. The MF4 (four filter model) also includes NO and NC closed contacts that can be used by the MF to receive and send notice of an alarm conditions, which are programmable by the operator. While very economically priced, the MicroFlush provides the most features of any filter controller offered today! Not only monitoring and controlling the V-Series filters, but other filter types as well.

Additional Applications:

  • Agriculture
  • Aquaculture
  • Aviation
  • Ballast Water
  • Car Industry
  • Car Wash
  • Chemical Industry
  • Cooling Water
  • Drinking Water
  • Electronics
  • Food & Beverage
  • Food Industry
  • Golf & Turf
  • Greenhouses & Nursery
  • High Rise Building
  • HVAC
  • Injection Molding
  • Metal Processing
  • Mining
  • Oil & Gas
  • Petrochemical
  • Pharmaceutical
  • Plastic Industry
  • Potable Water
  • Power Generation
  • Pulp & Paper
  • Pump Seals
  • Reinjection
  • RO Filtration
  • Seawater Filtration
  • Spray Nozzle Protection
  • Steel Industry
  • Textile Industry
  • Wastewater

Additional Resources

  2. US Department of Energy - Technical Evaluation of Side Stream Filtration for Cooling Towers 
  3. VAF™ Filtration Systems

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Comprehensive Energy Services

Written by Comprehensive Energy Services

Comprehensive Energy Services, Inc. is an award-winning, self performing provider and recognized leader in Design Build and Maintain Mechanical Contracting and Plumbing; providing a full range of advanced HVAC commercial, healthcare, and industrial services, including mechanical engineering design, mechanical construction, plumbing, IAQ, preventative maintenance and system maintenance throughout Florida.


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