Tiverton High School : Bandvulc Tyres: The Environment Agency : Devon County Council : The Eden Project : DML

The Business case
"This system is all part of our approach to our environmental principles and part of our belief that we should practice what we teach" - Managing Director, Patrick O' Connell.

Company Profile
Bandvulc produces remoulded tyres for heavy goods vehicles at a factory on the outskirts of Plymouth. The company has an annual turnover of £22 million and employs 240 staff. Energy consumption in 2005 was approximately 10.3 million kWh, worth £300,000.   This represents 3.75% of total turnover.

Introduction
"This case study examines the benefits to Bandvulc of measuring its gas, electricity and water supplies with ½ hourly remotely read meters."

Achievements
The factory has:

• Reduced gas consumption by £12,777 per annum
• Lagging of condensate tank (hot well)
• Improved presses' heating efficiency through lagging (better quality product too)
• Reduced electrical power consumption by £37,349.93 per annum
• Installed sunpipes in offices (natural lighting)
• Installed new lighting system
• Reduced water use & meter actual sewage charges
• Raised company's awareness and promoted "good housekeeping" practices

The Technical Case

Installing Half-Hourly Meter Readers
"Like most industrial sites, Bandvulc only had access to 30 minute data for the main electricity meter, and even then only up to a month after the event. There was no way to obtain detailed profile data for gas and water, or for the outside air temperature and other factors that were driving variations in energy consumption.   Also there was no sub metering of different processes on site."

A CHICK meter reading system from Energy Metering Technology was installed by C3 Resources in July 2004.   The system consists of small radio transmitters connected to each of the meters, counting the pulses from the meters and reporting to a logger on site.   Each of the meters had to be adapted to produce a pulse output.   The cost of the installation was £4,610.

The installation was conducted during working hours with no disruption to normal activities.

The system reports through a DYNAMATplus software package on a dedicated PC on site, and can also be dialled up remotely by C3 Resources and the EMT / LEA bureau team based in Leicester.

Working and operational hours
Production hours are 24 hours a day from 6am Monday to 6am Saturday each week, with 2 week shutdowns both over the Christmas / New Year period and over summer.

Energy Profiles
The electricity profile shows a good "aspect ratio" with steady usage during the night shift, higher usage in the day when the administrative staff are present, and low usage at weekends when the site is unoccupied.

The gas profile shows virtually constant usage during production hours, with little variation to reflect changes in the weather or the number of tyres produced.   This led the staff to suspect that much of the gas consumption was going to meet the standing losses.

The water profile from the first week that the system operated shows a high base load. The water consumption shows a base load at weekends, which was due to mechanically controlled urinals, and peaks, which coincide with showers during shift-changes.

•  Energy Savings Identification
The system immediately showed that after a short warm-up period when the steam boilers were started each Sunday, gas consumption was constant at approximately 1.1MW throughout production hours, without the expected variation in line with rate of production.   This meant that the standing losses in the type presses and steam distribution system were very large compared with the amount of heat actually going into the product.

•  Implementation
In January 2005 Bandvulc began lagging their type presses, and this brought about a steady reduction in gas consumption.   After one year the cumulative savings were 800,000 kWh, worth £10,832 p.a. and 152 tonnes CO2.

In July 2005 the metering system was expanded to include eight electrical sub meters.   This allows specific processes within the factory to be monitored.   Attention then turned towards measures for saving electricity.

The lighting in the factory consisted of "high bay" high pressure sodium lamps that have a warm-up time of several minutes, meaning that they cannot be put under automatic control to make the most of natural daylight.   These were replaced with T5 fluorescent fittings connected to an occupancy and daylight sensitive control system.  

•  Graphs
The gas graph shows the cumulative gas savings achieved by lagging the tyre presses, based on autumn consumption.

The Financial Case

•  Savings
Annual gas saving was £10,852 (at Carbon Trust standard price - more in reality).   The cost of the lagging was £20,000, giving a 1.8 year payback.  

Annual electrical power saving was £37,349.93 (at Carbon Trust standard price - more in reality).   The cost of the lighting was £20,000, giving a 1.8 year payback

•  Costs
The total cost of the original meter reading system was £4,610.   The additional meters in the electrical switch room cost £1,000.

•  Payback
Based on the cost of the metering system and the measures implemented, overall payback was 0.12 years

Further projects

Heat recovery system
At the moment Bandvulc cools down the condensate via a fan & heat exchanger system to reduce flash steam. A heat recovery system will be fitted to the condensate line to use the energy in the flash steam to pre-heat the boiler feed-water.

Control of extraction motors
The current extraction system has no control to it. Variable speed drives will be fitted to the motors. Their speeds will be controlled, via   a PLC, by air-velocity meters and vanes in the ducting system.

Boiler start-up automation
The boiler is currently started every Sunday evening manually. This means the boiler is on at least six extra hours a day, which equates to over £5000 per annum. A fully automated system will be fitted.