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Wed 14 Jan 2009 04:00 AM

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Condensed working

Now the top option for new installations throughout Europe due mainly to their environmentally friendly characteristics, can the Middle East market also benefit from the use of condensing boilers? MEP Middle East examines their uptake and suitability for use in the Gulf market.

Now the top option for new installations throughout Europe due mainly to their environmentally friendly characteristics, can the Middle East market also benefit from the use of condensing boilers? MEP Middle East examines their uptake and suitability for use in the Gulf market.

Condensing boilers are a relatively new technology worldwide for use in water heating systems, but as the demands for energy efficiency have grown, so too has the application of such products.

In Europe they have been used as a source of water heating since the 1990s and are now the number one choice in some countries for new installations, being mandatory in both the UK and The Netherlands.

In the Middle East the market has begun to recognise and utilise the technology, but with limited gas networks in place and green building regulations in their infancy how can condensing boilers be effectively applied in the region?

The technology

The main feature of a condensing boiler is the recovery and reuse of the exhaust water vapour produced when burning the fuel, which is generally gas. This is condensed back into liquid form in a second heat exchanger within the unit, which heats the cold water returning to the boiler.

The condensation of this exhaust vapour enables energy recovery from the latent heat of vaporisation of the water, which produces a lower fuel use and higher operating efficiency.

"This new kind of technology is made to improve performance and efficiency of gas boilers because some of the heat made in the combustion is recovered," explains Merloni Termosanitari SpA (MTS) Middle East Marketing Manager Emanuele Stano. "The main benefits is there is less consumption, less pollution and money saving."

To enable this process to occur, condensing boilers have an additional heat exchanger compared to traditional alternatives, they are also manufactured from higher grade materials.

"Generally, condensing boilers are made out stainless steel [to provide] corrosion resistance," states Herbert Bremstaller, managing director of Ecotherm Austria.

Advances in technology and boiler manufacturing are also playing their part in the development of condensing boiler technology. "Classic boilers cannot reduce the flue gas temperature too much because when the temperatures are too low, condensate starts in the boiler and it will be damaged due to the corrosion of the steel or cast iron material," explains Viessmann Middle East general manager Murat Aydemir.

"With the improvement of stainless steel welding technology, new high efficient boilers don't have this problem any more, they can operate at any temperature and reduce the flue gas temperature down to 60oC - classic boilers usually [operate at] 200oC - which gives an efficiency increase of up to 15%," adds Aydemir.

High operational efficiency is one of the principal benefits of condensing boilers as this can be significantly higher than alternative products. This in turn provides strong environmental advantages.

"Energy efficiency of up to 99% [can be achieved]," states Faisal Jassim Trading general manager Raphael Khlat. "They provide a NOx level of only 20ppm, they are a compact design and easy to install," adds Khlat.

"Gas fuels have half of the CO2 emissions of fuel oils; together with the high efficiency of condensing boilers you can have the lowest CO2 emissions in the industry," stresses Aydemir.

"A classic boiler has an efficiency of approximately 94% on the lower calorific value of fuel, which is not considering the latent energy of the fuel.  Due to the very low flue gas temperatures, condensing boilers can have an efficiency of 98% even without condensing," he adds.

Technology applications

There are a number of applications where the use of condensing boilers will be most effective. In the Middle East, the most efficient application is for indirect hot water heating systems.

Aydemir explains: "In many hotels a large boiler is used for steam supply and hot water generation. Steam boilers have a low efficiency due to the high operation temperatures and steam systems have high losses; when you connect the hot water systems to a condensing boiler you will have savings of up to 30% compared to a steam system and the condensing boilers are almost maintenance free."

Applications with a return temperature of less than 40°C are ideal adds Bremstaller.

"The boilers will give full condensation of the flue gases by having 110% efficiency (based on LCV), because the dew point of natural gas is 56°C, which is perfect for DHW [domestic hot water] installations," he explains.

Despite their advantages, there are some applications where condensing boilers should not be used, so care must be taken when designing a system while considering their use.

"If you have heavy oil you cannot use condensing boilers - the high sulphur content has a very high corrosion on the surfaces," explains Aydemir. Systems with flow temperatures of more than 110°C also prove unsuitable reports Bremstaller, as are those that are supplying process steam applications.

The cost of the products can also be prohibitive in some cases as can unit capacity. "They are almost 40-50% more expensive than conventional boilers," reports Stano. "Capacity is limited," adds Khlat, "and the actual operating efficiency of a condensing boiler depends on the ambient air temperature and the relative humidity," he explains.

Market uptake

The application of condensing boilers is relatively new to the Middle East, with installations beginning only a few years ago and they are especially being used as a back-up for solar heating systems.

Traditionally fire tube boilers were used in the Middle East for steam and hot water generation, while cast iron boilers were used for hot water generation only.

In Europe the application of condensing boilers is now well established, the technology having been introduced in the 1990s.

"The wall hung condensing boiler market is highly concentrated: the UK represents close to 50% of the total market, followed by the Netherlands and Germany, which account for 16 and 15% respectively. Thus, around 80% of the total condensing market is accounted for by just three countries. The next biggest markets are Japan, South Korea and Italy," reports Aydemir.

The Middle East condensing boiler market is currently quite small compared to that worldwide. "The main reason for that is that many countries are not using boilers for heating," Aydemir explains.

"In the UAE, for example, boilers are used for heating domestic hot water or for generating steam. In steam boilers you cannot use condensing technology as the temperatures are too high; you might add a condensing economiser to a steam boiler, but then you have to find a low temperature  circuit for high efficiency," he adds.

Market growth rates currently vary significantly between countries. The current uptake in the Middle East is undergoing only a gradual rise due to the relatively high price and limited capacity of the units, adds Khlat. "The uptake abroad is faster since smaller capacities are more required," he explains.The general level of construction activity, however, means that a higher growth potential is evident in the region than in more established markets and legislation is also expected to play a role in this demand: "In the UK and Holland [their use] is a must by law," reports Aydemir.

Manfacturers expect the Gulf market to follow Europe's lead, with a number of changes predicted. "The problem here is that there is no gas networks present, so if a client wants to use condensing boilers they would have to store their own supply," explains Stano."But many hotels are trying to move to condensing boilers that are connected to solar systems to provide hot water supplies," he adds.

"We believe that in the upcoming years [the use of condensing boilers] will breakthrough in the Middle East region because of upcoming standards and developing gas networks," opines Bremstaller. "Everybody is aware that condensing technology is the right choice for the future," adds Aydemir.

"The rest of the world has started to use this technology almost 20 years back; the market share is still increasing and I guess after 2015 the market will be dominated by condensing boilers and regular boilers will have a small share," predicts Aydemir.

The total world domestic boiler market was estimated at US$10.9 billion and 10.46 million units in 2005 and is expected to grow at a moderate rate over the next few years.

The relation of the individual market segments is expected to change over the forecast period: wall hung, non-condensing boilers that represent about 50% of the total market in volume, are expected to show decline over the next years, reports Aydemir.

"Condensing boilers on the other hand, are going to grow rapidly. They are growing at a rate of over 15% per year. The share of condensing boilers on the total boiler market will rise from about 20% to 27% until 2010," Aydemir predicts.

"The main push for this technology will come with some laws imposing standards in performance and efficiency - this will be the key - and if a gas network is developed in the country, otherwise it will be difficult for the end-users to apply," adds Stano.

Product availability

There are several condensing boilers available in the Middle East market. Ecotherm offers Hoval's floor-standing UltraGas product, which includes the premix burner technology UltraClean.

The vertical unit features aluFer heat exchanger technology, which has aluminium on the fire side and stainless steel on the water side to increase conductivity, heat transfer and efficiency. The factory preassembled units have a low electrical consumption and sound and vibration.

The Cleaver Brooks Clear Fire combustion system from Faisal Jassim Trading features a pre-mix down-firing burner, high quality stainless steel combustion chamber with single pass AluFer tubes made of stainless steel, with an aluminium alloy finned internal surface.

The insulated boiler is encased within powder-coated steel panels. A heating pump control with over-run facility is included, as is a fault diagnostic indication, dual safety shut-off valves, electronic modulation and a facility for controlling a domestic water pump.

Viessmann offers a number of condensing boiler ranges including the Vitodens gas-fired, wall-mounted series. The Vitodens 200 offers technology for central and domestic hot water applications.

It features an Inox-Radial heating surface and modulating stainless steel cylinder burner. Vitodens 300 combines the modulating MatriX-compact gas burner with the stainless steel Inox-Radial heating surface.

The Vitodens 333 combines the Vitodens 300 condensing boiler with a high output 86l domestic hot water loading cylinder. All have been certified for environmental output.

The firm's Vitocrossal 300 is a freestanding gas-fired condensing boiler. Available in outputs of 9-978kW, it can be used in applications ranging from individual homes to commercial buildings and local heating networks.

Balanced flue operation is feasible up to 66 kW, enabling the product to be installed inside the thermally insulated building envelope.

Local installations

Condensing boilers are now being used in a number of high profile projects, with several other installations under way. At the Shoreline Apartments on Dubai's Palm Jumeirah, Ecotherm provided six turnkey solar hot water systems that include two skid-mounted Hoval Ultra Gas condensing boilers that will work in conjunction with the 200m2 high performance trough solar collectors.

For the Ramada Hotel in Doha, Ecotherm provided a turnkey gas-fired boiler hot water system that included two 1,1150kW triple-pass boilers.

The Burj Dubai is also set to gain from the technology as Ecotherm is providing 11 skid-mounted turnkey systems of 300kW capacity, which will include its gas-fired condensing boilers. In each case the units were selected for both economical and ecological reasons.

Faisal Jassim has also provided condensing boilers for the Palm Jumeirah, with projected potential cost and energy savings being key decision makers in the selection of the units.

Viessmann products have been used on several projects in the region, including the Palm Jumeirah Shoreline Apartments and Dubai Festival City.

Most recently, it has supplied three Vitocrossal 300 condensing boilers for the five-star Ottoman Palace Hotel on Palm Jumeirah, the installation of which began in late 2008. Here the system will provide steam to areas such as the laundry and kitchens and hot water for all hot water circuits in the development, including the pool heating.

"We offered these boilers [for the projects due to their] higher efficiency and lower CO2 emissions," explains Aydemir. "Also, as Viessmann we have got SNG (an LPG-air mixture) approval from an European laboratory for our condensing boilers on the Palm," he adds.

With significant potential energy and operational costs savings compared to their traditional alternatives, plus strong environmental credentials, it is certain that the technology will become more common in future projects throughout the region.

CONDENSING BOILERS: The pros and cons

Advantages

• High efficiency compared to traditional boiler types

• Reduced fuel requirements

• Lower NOx emissions

• Low maintenance

• Very compact design

• Easy to install

Subhead: Disadvantages

• Higher initial capital cost

• Limited capacity

• Operating efficiency is dependent on the ambient air temperature and relative humidity

• The condensation process produces an acidic liquid (due to sulphur and nitrogen impurities), which requires the use of special materials and the addition of a fluid draining system

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