Generating steam

Although the environmental benefits of energy efficiency is fairly obvious, laundry operators – and accountants – are perhaps more interested in the substantial cost savings that energy-efficient measures can deliver.

With the laundry industry increasingly keen to maximise margins by driving down costs, it seems that energy is one area where it is relatively easy to generate savings. Many technologies exist that can help reduce energy consumption, and any saving on energy cost has a direct impact on profits.

Heating water is perhaps the biggest single energy cost in a laundry, but equipment is now available that makes boilers more efficient and can reduce unnecessary firing.

It is perhaps not generally appreciate how fast boiler technology has progressed – it is far superior to what it was five years ago. If a boiler that is more than ten years old is replaced, then it will pay for itself in less than two years, but the attitude all too often is “if it ain’t broke, don’t fix it.”

Governments around the world are starting to target energy efficiency, and more subsidies are likely to be available in the future.

In the UK, for instance, efficient boilers are now on the list of capital allowances, and the government is offering interest-free loans to attract small and medium-sized operators that do not have their own technology departments.

Fulton Boiler Works’ RBC range of horizontal wet-back fire tube boilers are available with optional Nu-way burners approved for the government-backed ECA (Enhanced Capital Allowance) scheme.

The ECA scheme is run by the Inland Revenue, DEFRA and the Department of Enivorment in collaboration with the Carbon Trust.

The scheme allows businesses to write off the capital cost of approved energy-saving technology and products against taxable profits in the first year of the investment.

Fulton sales and marketing director Gordon Bareham said the company produces skid-mounted systems, designed to be easily installed in boiler houses. “They are delivered to site as fully tested and functioning systems, requiring minimal on-site installation work to connect them to existing services” he said. Single or multiple skid-mounted systems based on Fulton’s boilers are available with the necessary ancillary plant for a range of applications.

Thermax Process Heat, a division of ME Engineering, has introduced a range of low-cost package shell boilers that are said to be easy to install, and suitable for industrial applications, including laundry.

The Shellmax CE and Revotherm CE boilers can be fired on light or heavy oil or on gas.

Both benefit from corrugated furnaces which, says the company, make them more flexible than traditional designs, reduce the effect of thermal stress and so extend the life of the boiler.

The Shellmax is a conventional three-pass wetback design and is available in capacities of 1,000kg/hr to 20,000kg/hr. It can be fitted with a heat recovery unit called an economiser that uses waste hear to pre-heat the feedwater, raising efficiency to 95%.

The Revotherm is a reverse flame, three-pass unit that is available in capacities of 500kg/hr to 8,000kg/hr.

It incorporates spiral gas agitators in the convective tubes that regulate the temperature of the exit gas and create turbulent flow of flue gases, even during the partial load operation often encountered by laundry boilers.

Both the Shellmax and the Revotherm boilers have output pressures of 10.54barg and 17.5barg (the pressure of a system as viewed on a pressure gauge, which does not include atmospheric pressure).

Both boilers have been designed to be easy to install, maintain and operate. Each has built-in unrestricted access to the water side of the boiler.

Forced draught burners are mounted at the front of the boiler with heat resistant doors, which can be opened quickly to give access to the fireside.

A common problem encountered in the drycleaning sector relates to a boiler’s inability to maintain the required pressure during the course of the day.

This problem often results in work having to stop whilst the steam regenerates. To overcome this problem, Controlled Flame Boilers (CFB) has designed the steam chamber of its 4VT range of steam boilers so that it is approximately 30% larger than most other vertical boilers, therefore enabling it to respond more effectively to peaks and troughs in demand.

Two common problems encountered in this industry sector are wet steam, which contains water droplets and effectively insulates the heat transfer surfaces, and priming, when a sudden surge in demand causes an abrupt drop in boiler pressure and the entire contents of the boiler becomes a foam. This can flow into the steam main and so bring the entire plant to a halt.

CFB says the increased capacity of the CFB 4VT boiler virtually eliminates the possibility of priming and avoids excessive amounts of moisture being carried over in the steam-creating dryer stream.

CFB developed its CFB4VT series with the aim of cutting fuel and maintenance costs while allowing the cleaner to produce a good finish on clothes.

The design makes it possible to produce steam with a very good dryness fraction, so avoiding problems caused by excessive amounts of water being carried over in the steam.

This produces a much drier and crisper finish on textiles. Dry steam also avoids the deterioration of both the plant’s pipe work and the steam batteries which convert the steam to heat.

Frequent descaling is not required, and the boilers last longer. Wear and tear on drycleaning equipment is also reduced, so running costs are lower.

As the generated heat is passed over the water-heating surfaces four times, by means of four specially engineered ports and fins, the 4VT is able to make best use of combustion gases.

The 4VT boiler is able to reach full output within 15minutes, significantly reducing start-up times as well as cutting down on both fuel and water.

Businesses do not have to pay an additional hour or more of staff time just to get the boiler ready for work. A faster start-up also reduces fuel and water costs.

Drycleaners with limited space can opt for the Slim Jim, part of the 4VT series that can fit through standard doorways and fit into corners, so making it easier to install in a basement or the rear of shop premises.