Wireless monitoring of compressed air system

A SensiNet wireless monitoring system has been deployed to monitor the compressed air system at the Hollingsworth and Vose plant in Massachusetts, gaining 50% in energy efficiency on compressor use

Hollingsworth and Vose, with advanced R+D and pilot manufacturing facilities, drives value in customers products by inventing next-generation materials with superior performance.

H+V products are found in applications such as engine filtration, high-efficiency air and liquid filtration, battery separators, gasket materials, and specialty and industrial non-wovens.

The Hollingsworth and Vose paper mill in Ayer, Massachusetts uses compressed air to power equipment in their manufacturing facility.

According to the Department of Energy, over USD1.5 billion per year is spent by US industry on the electricity used to compress air.

The average compressed air system runs at a 30 to 50% inefficiency, resulting in higher than needed operating costs.

National Grid provides electricity and natural gas to the Hollingsworth and Vose facility in Ayer, and is interested in containing and lowering electric usage in this service area through joint programmes with customers, focused on conserving electricity.

The objective was to improve the efficiency of the paper mill compressed air system, lower the electricity expense component of manufacturing cost, and conserve energy, which would also lead to lowered greenhouse gas emissions.

Because compressed air systems degrade over time and become leaky and inefficient, the system operator compensates by increasing the line pressure delivered by the air compressor.

This results in the air compressor running more often in order to compensate for the degradation of the distribution lines.

Inspections are performed infrequently - usually once a year - and as a result, systems operate inefficiently and use excessive electricity for long periods of time.

Hollingsworth and Vose wanted to increase the frequency of system inspections but wanted to avoid the high cost of employing manual labour to do this.

Proposals for a traditional wired networking monitoring system were too expensive and also fell outside the eligibility range for reimbursement from National Grid, which happens to have a subsidiary, National Grid Wireless, that provides telecommunications infrastructure and services.

A SensiNet wireless system was therefore deployed to monitor the compressed air system in the plant.

The SensiNet wireless capability made the system cost effective and very easy to install in this crowded paper mill manufacturing line.

The SensiNet system was configured to monitor key operating parameters of the system including temperature, line pressure, airflow, and energy usage of the compressor.

SensiNet software was employed to display the data, and the graphical user interface and data display made it easy to spot trends, identifying system degradation.

The monitoring and reporting interval was set at one minute.

A complete system profile was then measured every minute, and small changes in system performance became visible immediately.

This enabled facilities personnel to take corrective action immediately to restore the system to full efficiency and avoid increased costs due to unnecessary air compressor activity.

The overall result was a 50% efficiency gain on the compressed air system, which reduced annual operating costs by USD26,000, for five-year projected savings of USD130,000.

With a system cost of USD10,500, payback is 5 months and 5-year ROI is 13x.

Wireless capability made the system very cost effective - USD10,500 to deploy SensiNet compared to the projected cost of USD75,000 for a wired system.

This cost effectiveness qualified the system for a subsidy by National Grid, and Hollingsworth and Vose were reimbursed for the full price of the SensiNet system.

Back to top