admin, Author at Aquatherm

Express Linen Services, Blackpool, England

33 years after the construction of the famous Blackpool Tower in 1894, Express Laundry opened its doors for business.

Starting as a domestic laundry in 1927 the business has grown into one of the best recognised names in the UK laundry Industry. Today, both Tower and Laundry are thriving - one still attracting tourists
from all over the UK, the other providing a top quality linen rental service to the hundreds of hotels and guest houses that service the town's many visitors.

Over a partnership of 25 years, current owner, Eddie Bruce, and Chief Engineer, Gordon Edwards, have kept abreast of the latest developments in machinery and processes - often creating ideas that have kept their suppliers on their toes to deliver.

In the 1980s, Express was one of the early customers of Aquatherm's original design, and reported steam use of 0.16 kg per kg processed - unheard of at a time when 0.4 - 0.5 was the norm for the newest tunnel washer laundries.

30 years later, with all of the original machinery upgraded—some more than once—to ’state of the art’ the decision was made to install water recovery as a means of saving both energy and water.

This did not prove successful and a couple of years later Aquatherm was brought in to install a system to recover and reuse the significant volume of energy that was being lost to drain.

The Aquatherm deals with two Lavatec tunnels processing a mixture of hospitality and NHS linen. Clever use of chemicals and flows enables the laundry to achieve rinsing temperatures of over 50 C which results in faster and cheaper drying and finishing - a saving not included in the figures reported by the Aquatherm’s data records.

The unit was installed and commissioned entirely by the engineering team at Express, and was running within days of being delivered to site.

A visit to site a year later revealed that an average of 10,760 litres per hour was being heated from 8.1 C to 35.2 C using the waste water as a source. In turn the waste water was being cooled from 56.4 degrees to 24, resulting in a total recovery of 68% of the available energy.

Vejle Sygehus, Danmark

In common with most European and Scandinavian countries, many hospitals and public institutions in Danmark have turned to the private sector for the provision of linen services.
One of the few remaining that have decided to retain their own processing facility is Vejle Sygehus (Sudenske Vaskeriet) located in the historic town of 55,000 inhabitants in Jylland (Jutland).

The laundry was established in 1980 and re-equipped with modern equipment in the early 2000's. Processing 6-7 tonnes per day, the main washing plant comprises 2 x Senking, 12 compartment P18 tunnel washers with SEP 50 type presses, and a total of 5 x Senking and 2 older Passal dryers – all equipped with cross-flow plate exchangers to reduce energy use.
Although the benefits of having an ‘on site’ service are many, the public sector is nevertheless duty-bound to obtain best value for money, and to keep processing costs to a minimum.

For thirty years, the processing methods and chemicals have been supplied by Novadan, which in 2010 served more than 50% of Danish laundries. Early in 2011, René Larsen , the chemist who had already achieved major savings in water and energy, proposed that the laundry invest in an Aquatherm Waste Water Heat Recovery System. A study was made of the flows and temperatures, and it was conservatively estimated that the total cost, including installation, would be recovered from energy savings in less than a year.

All of the waste water from both tunnels, including press extract water, was individually piped to a two cubic metre insulated tank adjacent to the machines, the mixed contents averaging 47°C.

An Aquatherm V20 automatically extracts the energy from the waste water, the resultant flow going to the outside drain at 5-6°C above the incoming cold fresh water – a recovery of 84%.

A second collection tank is used to store some of the cooled effluent, which is used to supply the washer extractors with water for the pre-wash and main wash. The rinses use fresh water.

Re-used water contains the 16-20% of energy not recovered by Aquatherm, and assuming 30% re-use, this boosts the recovery of energy used for washing to nearly 90% - without any need for cleaning or maintenance.

Apart from the direct energy saving, the extractor now operates with the linen at over 40°C, which reduces the moisture content and results in lower energy consumption for drying and finishing.

Using a clear 10” colour touch screen, the Danish staff can monitor flows and temperatures at all times, and all data is written to a data chip every second to provide a detailed record of performance whenever the plant is running.

Victoria Hospital Kirkcaldy, Scotland

In 2008 the Victoria NHS Laundry was struggling to deal with the workload being processed through the 2 Senking tunnels they had installed some years earlier.

George Ronald, the Estates Officer responsible for the engineering and building aspects of the plant had picked up on a reference to ‘side effects’ mentioned in the Aquatherm brochure that he had received – in particular the claim that waste water heat recovery reduced drying time of tumbler driers.

With the increased load that the laundry was being asked to process, drying had become a major bottleneck to production, and the concept of being able to reduce drying times by 20% and save energy at the same time was attractive.

After Aquatherm made a detailed survey it became clear that although a full waste water heat recovery system was viable on paper, the site conditions were far from ideal.

The main water storage tanks and drainage system used by the laundry are located in a sub basement under the production floor, access to which is by a narrow flight of stairs.

Once inside the basement the picture did not improve… A mixture of cast iron drains feeds waste effluent into a brick built buffer tank from which there is an outlet to the exterior drain. With around 13 cubic metres of waste water at a temperature of over 40 degrees, 60 hours per week the loss of energy was equivalent to £57,000 – a situation that could not be allowed to continue.

Despite regular attention the pit would also become clogged with lint, plastic bags and small articles on linen. As Aquatherm prepared for the installation specialist contractors were working in the basement to remove
the asbestos insulation used in earlier days to save energy….

The solution was as elegant as it was effective. First of all a stainless steel collection tank was installed to intercept the waste water drains from the wash house. The water collected was channelled through a tailor made rotary screen to remove the various detritus and then buffered in the original brick tank.

From the tank, waste water is pumped through the Aquatherm to drain at a controlled flow matching the demand of fresh water called for by the washing machinery.

Starting at around 42 degrees the waste water temperature rose to over 50 degrees—the so called ‘flywheel effect’ before being cooled by the incoming cold water to between 15 and 20 degrees, depending on the ambient temperature at the time of year.

Estates Manager Dale Stewart (who had taken over the project) initially anticipated that the system would pay for itself in a year in direct fuel savings. In fact the system was operating so efficiently, feed temperatures were at times a little high for the process and some stain setting occurred. The ‘not to exceed’ temperature control in Aquatherm was set to 40 degrees, which dealt with the situation although prolonged the full payback by a few weeks. Linen Service manager Andrew Greer was delighted with the improvement in drying – times cut by a quarter – and the increase in productivity that resulted.

And just how did our installation engineer get 750kg of Aquatherm down two flights of stairs without a scratch? When questioned, he smiled and said as he walked away – ’very quietly – you don’t want to know’

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