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Taking the heat off

Heat exchangers represent the most basic yet fundamental feature of any air conditioning and refrigeration process. Still, this market segment is often overlooked. Valeria Camerino sheds some light on the latest trends, technologies and applications for this key HVACR component.

| | Jun 30, 2011 | 1:53 am
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Heat exchangers represent the most basic yet fundamental feature of any air conditioning and refrigeration process. Still, this market segment is often overlooked. Valeria Camerino sheds some light on the latest trends, technologies and applications for this key HVACR component.

As Pramod Padmanabhan, Director – Middle East Operations at Gulf Sondex explains, heat exchangers are an industrial application of convective heat transfer and heat transmission. Several approaches can be used for classification of heat exchangers, including the classification by action principles, purposes and materials. As heat transfer equipment, heat exchangers are widely used in industries, especially in those fields requiring high energy consumption.

In recent years, different types of heat exchangers have been introduced into the market, as a result of the rapid development of energy-saving technology, Padmanabhan says.

“Currently, Saudi Arabia and Qatar are the two largest markets, where we expect a boom in the near future,” he reveals.

The company, which has been involved in a number of regional projects, including King Abdulla Financial District in Riyadh, Saudi Arabia, Central Market Redevelopment, in Abu Dhabi and Barwa Commercial Avenue in Qatar, specialises in the developing and manufacturing of gasketed plate heat exchangers, semi-welded plate heat exchangers, free flow plate heat exchangers and brazed plate heat exchangers for a large number of segments.

Those include HVAC, industrial, food, dairy, hygienic, refrigeration and marine applications.

Furthermore, in order to better cater for the needs of its clients in Dammam, Riyadh, Jeddah and other Saudi cities, the group, which boasts an international presence, has recently opened a new office in Saudi Arabia.

Shwan Lamei, Area Sales Manager, Middle East at SWEP International, also sees many investment opportunities in Saudi Arabia.

The company, which is “fairly new to the [Middle East] market”, focuses on air conditioning, including evaporators and condensers, district cooling and other water-related applications.

“The biggest markets for chiller applications are the UAE, Egypt, Saudi Arabia and Jordan, where the large OEM producers are located,” Lamei says.

He claims that SWEP’s sales numbers have not been affected by the downturn. “On the contrary, we experienced rapid sales growth during the crisis,” he points out.

In Padmanabhan’s view, for the food and dairy industry, the refrigeration sector, as well as the industrial and marine segment, the main challenge is to carry out the cooling operations with minimum energy consumption.

For Chetan Gajria, Market Unit Manager-Comfort at Alfa Laval, the heat exchanger market is growing steadily but “not as much as in 2008”.

The company has been involved in a number of major regional projects, including the ski slope at Dubai’s Mall of the Emirates, Burj Khalifa, Emirates Palace in Abu Dhabi, The Pearl in Qatar, Bahrain World Trade Centre, and the Kingdom Centre in Riyadh.

“Country wise, it is very clear which countries will have large projects over the next few years,” he says. “But the region as a whole is seeing enormous growth in population and per capita income is on average higher than global numbers.”

Gajria explains that investment is high in sustainable and energy-efficient products.

“A large number of countries have been operating at an artificially low price for gas, which means that over time the price will increase and have a domino effect on all utilities,” he says. “The industry sees this and is starting to demand more efficient products and designs.”

Alfa Laval Comfort division’s client-based is made up of contractors and end-use district cooling providers. “The demand is still strong in the traditional base and new avenues are opening up every day,” Gajria points out.
In his view, plate heat exchangers are experiencing a broad transformation with the Air-Conditioning, Heating, and Refrigeration Institute (AHRI) standards now gaining acceptance. Technologies like brazed heat exchangers, fully welded plate heat exchangers and double walled units are being used more and more, replacing legacy technologies.

“The brazed technology is well-established in virtually all regions across the world, except for the Middle East,” argues Lamei.

He adds that SWEP can provide brazed plate heat exchangers (BPHEs) with asymmetric designs.

Some BPHEs are available with different types of channel plates where the herring-bone pattern varies. By mixing different plates (high, medium, low resistance), the thermal characteristics of the BPHE can be modified.

Siraj Nettikkadan, Alfa Laval’s Market Unit Manager – Refrigeration, acknowledges that the market is increasingly moving towards a commoditisation of the product, as customers place great emphasis on cost. “We are the market leaders, so we have to be the benchmark,” he says.

However, Padmanabhan from Gulf Sondex holds a different view: “Customers have never compromised on quality due to the cost factor,” he says. “They regard performance capability of products as highly important.”

The company educates its customers on the long-term benefits of using its products “that are designed to enhance performance and considerably reduce the downtime during service or shutdowns especially considering the critical application of heat exchangers in the HVAC industry”.

Sondex is also trying to educate its existing customers on the importance of maintaining the systems clean in order to save energy costs.

“Although cost is important, I feel that space saving, along with operational dependability are also gaining importance,” Lamei observes.

As Nettikkadan explains, Alfa Laval is working closely with potential customers to convince them of the safety benefits of its products.

“However, we now give them options so that they can choose keeping in mind the cost associated with it,” he says.

Gajria observes that in view of the financial slowdown of the last few years, it should come as no surprise that customers place a strong emphasis on cost.

“Solutions like direct connect might be plausible solutions on some projects, but the advantage of using PHEs [plate heat exchangers] cannot be disregarded,” he says. “We have all seen the Middle East market maturing at a very high pace on acceptability, purchase and installation. But it will need time to reach the same level with operational information and feedback.”

He argues that only recently, loads have increased and actual performance issues have come to light.

“Expect a correction as the results of extremely controlled capital expenditure manifest themselves as higher operation expenditure,” Gajria says.

He explains that many of Alfa Laval’s partners are re-thinking the way they design their systems to make them suitable for different building heights.

“We regularly provide support on issues like part load performance and what-if scenarios to help our customers understand the actual impact of real-life situations on heat exchangers,” Gajria claims.

He observes that hydrostatic testing is a minimum requirement for any pressure vessel. But as the heat exchangers are at the heart of any building, performance testing is also necessary.

“Every manufacturer will claim one parameter or the other,” he says. “Alfa Laval believes that by working with an industry standard like AHRI, we will all – manufacturers, contractors, designers – be on the same page. We strongly support this industry initiative.”

As Padmanabhan explains, Sondex has gained EN ISO 9001:2008 Quality Standard certification – recognition. The company also follows industry standards as per ASME “U” stamp, PED 97/23/EC, National Board Certification and AD2000 design requirements.

“[The ASME “U” stamp] accreditation is the culmination of intense work including an analysis of internal processes, rectification of any identified shortcomings and the implementation of statistical measures. These processes are reinforced by effective communication,” Padmanabhan says.

The company has carried out performance tests as per AHRI. These certified units have been supplied to St Regis Resort in Saadiyat Island in Abu Dhabi, UAE.

As he explains, Heat Exchanger Performance Monitoring is a standardised procedure that can be tailored to each individual customer, he says. The performance parameters that are assessed in the process include effect [MW], temperature efficiency [-] and terminal temperature difference [ºC].

Some heat exchanger manufacturers are not fully satisfied with current installation practices.

“A large number of present installations turn out to be installed, connected and forgotten with little emphasis on enabling maintenance. Operators experience the difficulties and usually have no choice but to live with it,” Gajria says.

In his opinion, Operations and Maintenance should be a part of the decision making process at the time of capital expenditure in order to make the life-time costs of the systems more transparent.

For Nettikkadan, one of the main installation issues is that most end-users prefer to keep the size of the plant room to minimum.

As a result, they don’t leave enough space to remove the plates and gaskets for service after five years or so. “Generally there will be a vessel above the unit and there will not be provision for a lifting hoist for future service requirements,” he explains.

Padmanabhan claims that he is not aware of any installation issues as installation and commissioning is supervised by Sondex’s engineering team.
Gajria observes that, unlike other countries in the world where heating is the dominant power application, the GCC market is largely characterised by hot weather and, as such, air conditioning and cooling are widely used.

The company has introduced a number of technologies, such as NTU plates and lower channel sizes to address these challenges, along with new technologies such as the T series of heat exchangers and double-walled units for domestic water cooling/heating.

For Lamei from SWEP International, over-dimensioned systems, that in some cases can cause decreased performance at lower loads, are among the key challenges of the GCC heat exchanger market.

Both Nettikkadan and Gajria advocate for greater operator and end-users’ involvement in the CAPEX decision making process.

“This is a culture that prevails in Europe,” Nettikkadan says, “but it will take much longer [here] for CAPEX to be replaced by OPEX as the main driving force in the decision making process.”

“Maintenance contracts with suppliers are being largely overlooked,” Gajria argues, adding that if they become a standard demand, they would result in minimal cost for the customer, but at the same time, they would ensure a higher uptime and lower reaction times.

He also calls for a review of design technologies.

“Design philosophy need to change. A very low LMTD [log mean temperature difference] is still looked at as an efficient system design, which is not true. By saving that degree, you are causing the equipment to become more expensive and the system’s heat transfer coefficient to drop considerably. As a result, the system becomes very unreliable,” Gajria says.

He continues: “Add to that the normal part load scenarios and you have an oversized system that is a disaster to control.”

In his view, a comparison with electrical thermal storage (ETS) design philosophy and sizes from other established cooling markets in the world might help identifying potential room for improvement.

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