Steam Reduces Energy Bill For Westferry Printers
Westferry Printers is making substantial cost and energy savings thanks to the Cubit steam generators which provide humidification at its Docklands printing facility.
Westferry is one of the largest and best equipped printers of national newspapers in Europe. Using 18 Goss presses it prints around 27 million newspapers each week for both regional and national publishers.
Westferry uses over 320,000 tonnes of paper and some 3,640 tonnes of ink per annum. Both paper and ink need to be stored and used in the correct environment to prevent product denigration and damage to the presses.
Originally Westferry relied on 38 individual 40kW electrode humidification units to maintain moisture levels. At the time of their installation they were the most practical solution. As technology moved on and it increased its portfolio, Westferry’s humidification requirements became more sophisticated with reliability a key issue.
Although effective, the electrode units were costly to run and difficult to maintain. Scaling required cylinders to be replaced on a regular basis resulting in costly spares, loss of time and high labour costs. Energy loss was also considerable through drain down and high condensation loss.
Although a large complex and fully air conditioned, humidification was only required in the reel stands and the press hall and only during the Winter months. The rest of the time the air handlers in the plant room provide fresh air free cooling.
Only 6% fresh air is used in the Winter months, requiring 50%RH. Humidification is also necessary during the summer if the temperature rises above 25ºC.
The decision was made to evaluate alternative systems. A cost-benefit analysis looking at running cost comparisons of gas versus electricity, annual maintenance costs and budget gas installation costs, favoured the Cubit steam system.
As a result three gas-fired System III units with triple burners were installed. Each system has a rating of 640Kg/hr F/A 100ºC at 5 bar giving a total installed rating of 1920kg/hr.
Each system is linked so that they share a common steam header which in turn feeds three separate pipe runs. Steam is then supplied to each AHU via a direct steam injection humidifier and control valve. This then humidifies the reel stands where the paper is held immediately prior to use as well as the press hall.
Both areas require 50%RH. When the atmosphere is too dry the paper becomes brittle and affects the glue’s consistency.
The cost of electricity alone to Westferry at the end of each week amounts to £24,500. The cost benefits of Cubit were very important for a company who is keen to support environmental issues and minimise wastage. Within the first year Westferry has achieved an annual energy saving of £100,000 and a maintenance saving of £26,000 bringing the total savings to £126,000 based on 1997 figures. This equates to a pay-back on investment in just two years.