Early payback for compressor upgrade

Edited by the Engineeringtalk editorial team Sep 24, 2003

Projected savings of GBP 15,000 per annum in energy costs have proved to be a compelling argument for shower manufacturer Kohler Mira in its choice of replacement compressors.

Projected savings of GBP 15,000 per annum in energy costs have proved to be a compelling argument for shower manufacturer Kohler Mira in its choice of replacement compressors.

The company has invested in four new Hydrovane compressors from CompAir to meet the needs for compressed air in two manufacturing units on its Cheltenham site.

A combination of the age of the existing compressors and a change in its needs for compressed air led the company to review its compressors as works engineer Dave Parry explains: "Our main objective was to look at replacing our existing compressors based on our current use of air.

In what we term our main building, there had been a reduction in demand for compressed air over the past three years.

In that building, we originally had three large compressors, although one had been replaced by a smaller spare because it was beyond economic repair.

There was a similar situation in our building 2, where we used to use a lot of air tools, but have now changed to electric.

The compressors we had were vastly oversized for our changed needs and, at the same time, were beyond their recommended running hours and spares for some were no longer available".

Changes in the patterns of usage of the air also prompted Kohler Mira to consider variable speed options.

As well as running a normal dayshift, the company operates a small night shift, with perhaps no more than six people, in both of the units so usage had become very variable.

To help the company reach a decision, distributor Servair brought in CompAir to run an analysis of current usage and provide comparative data for replacements.

Andrew Power, of Servair in Worcester explains: "CompAir ran a 7 day data-logging exercise and provided analysis to illustrate how much the customer could expect to save in energy costs by replacing the existing compressors with the recommended Hydrovane V22RS machines".

"Data logging is an extremely valuable exercise.

It is a nonintrusive process that gives an accurate picture of consumption and patterns of usage.

Using the data obtained, CompAir can run a computer model that shows the comparative costs of alternative configurations".

"If a number of different options are under consideration, the comparisons produced will help the customer make a much more informed purchasing decision.

And in our experience, the figures produced always provide a very accurate forecast of the levels of energy savings that can be achieved".

For Kohler Mira, these financial data considerably smoothed the path of the plant's capex application, as Dave Parry explains: "There was no questioning the figures.

The projected savings meant a good payback period for the new compressors and the degree of energy efficiency we were looking at was well in line with our company policy on meeting environmental standards".

The compressors recommended by Servair for Kohler Mira are Hydrovane HV22RS machines.

Available in 7, 15 and 22kW versions, the RS vane series is designed to offer the lowest running costs available from any compressor in this size range.

Typical energy savings, compared with equivalent single-speed compressors, can be between 30 and 50%, depending on system demand.

The key to its performance is an advanced inverter drive that has been combined with the refined rotary vane compressor design.

The inverter drive uses a transducer that senses airline pressure, providing a feedback signal to the integral PID control, which enables smooth acceleration and deceleration of the electric motor's speed.

This accurately regulates air output to exactly match system requirements.

This means that the energy consumed is only that directly needed to produce the customer's precise air requirements.

Both the RS Vane's inverter drive and Eff1 high-efficiency motor are approved under the Enhanced Capital Allowance scheme and the total compressor package, comprising compressor, electric motor, inverter drive and starter, comes complete with an Advance warranty scheme.

This is a built-in 5-year warranty, free of charge to the customer.