What are SEC and LCC?

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Specific Energy Consumption

Specific Energy Consumption (SEC) is a parameter used to evaluate the energy efficiency of an RO system. SEC is the kW-hr of electrical energy consumed in producing one cubic meter of permeate. There are a number of factors that need to be stated when an SEC figure is given. For example, does it include:

  1. Pre-treatment system?
  2. Post-treatment and permeate distribution?
  3. 2nd pass power consumption? (If used.)
  4. Facility's power consumption? (Lighting, air conditioning, etc.)
  5. All operating conditions, or just the conditions for one duty point?

RO systems typically operate over a wide range of pressures and SEC can vary significantly at different pressures

In regards to SEC for an ERD, many factors need to be understood to properly evaluate overall energy consumption:

  1. Does the ERD adversely affect feed pump efficiency? (Isobaric chambers can reduce pump efficiency.)
  2. Does the ERD adversely affect membrane performance? (Isobaric ERDs can introduce significant brine into the membranes, which raise the membrane pressure requirement.)
  3. Does the ERD require auxiliary equipment that consumes additional energy?

A modern feed pressure booster such as the HPB provides SEC values comparable to isobaric chambers. A special version of the HPB, call the HEMI, can rival the isobaric chamber SEC performance.

In general SEC has a greater significance in larger systems (where capital and maintenance costs may be proportionately smaller than in smaller systems) or where energy costs are very high.

A comprehensive SEC analysis is best with software that can closely calculate system performance under variable pressure operation. FEDCO can perform SEC analysis on a wide variety of ERD types. feed pumps and variable pressure operation.
Please contact us for details.

 

 

Life Cycle Cost

Life Cycle Cost (LCC) is the single most important parameter in determining the best use of capital in equipment purchases. Originally developed in the construction industry to evaluate building options, LCC analysis has spread throughout most industries. The LCCA has been modified to accommodate the needs of each industry, including the pumping equipment and ERD segments.

The US Hydraulic Institute and Europump have collaborated to develop an LCCA for pumping equipment. The most important conclusion drawn from the LCCA is that no single parameter determines the optimal equipment selection. At least nine parameters must be considered, as well as the timing of the cost, as illustrated in the figure below.

The LCC is simply the investment in a piece of equipment from the time specifications are issued to the time the equipment is decommissioned.  Simple put, the equipment with the lowest LCC represents the best use of funds.

LCCA

The LCC "weighs" these factors to determine the optimal investment for an ERD or pump, and also tells you how much money you have at "the end of the day."
The HPB usually has the lowest LCC of any ERD due to a superior balance of all cost factors.

LCCA

A comprehensive LCCA is best accomplished with software that can closely calculate SEC values as well as various capital and operating expenses associated with the HP pump and ERD. FEDCO can preform SEC analysis on a wide variety of ERD types, feed pumps and variable pressure operation.
Please contact us for details.