It is an irony of our times that we human beings have been increasingly contributing to air pollution, even as we keep coming up with ways of improving Indoor Air Quality (IAQ). Though we may take pride in the belief that indoor air quality is a modern-day concept, born of our concern for health and hygiene, and a necessary pre-requisite of any civilised society, history proves that such concerns were raised as early as around the mid-1200s. However, the subject has not received the attention it deserves. It is a fact that we might survive for two weeks without food and two days without water but only for two minutes without air. It is a precondition of life.

A normal adult processes 10 to 25 m3 (12 to 30 kilogrammes) of air per day [1,2]. Along with it, a lot of impurities also get processed through our respiratory system. Particles suspended in the air we breathe follow a flow path that goes through a sequence of airways as it travels from the trachea to the alveolar surfaces. The airways are lined with millions of cilia (micro-hairs) beating with a wavelike motion to propel mucus, microbes and dust, so that they are eventually coughed up. Once particles are inhaled, their retention duration in the lung varies, depending on their physicochemical properties, their location within the lungs, and the type of clearance mechanism involved. The health effects of inhaled particles depend on their chemical composition and particle size, as well as their deposition location. Particle deposition in the human respiratory system takes place in varying geometry, with flow that changes both in time and cycles in direction [1,3].

The finer points of air mechanics

An ideal start to understanding the engineering behind air filtration is simply to study air. Air properties, composition and the physics of its movement are fundamental to the behaviour of suspended particles. The key element in the analysis is examining the flow of air surrounding a particle, which requires a fluid mechanics approach, as it involves studying how particles may move in relation to air [1]. It is also important to take a closer look at the composition of air as shown in Figure 1. As is evident in the figure, air is a gas mixture which consists mainly of nitrogen and oxygen, and nearly one per cent of argon, neon, helium, krypton, hydrogen, xenon, traces of other gases and atmospheric impurities [4,5].

Sieving through misconceptions

There are a few misconceptions that need to be addressed and dispelled regarding air filtration. They can be summed up under the following rubrics:

• Particle straining
• Particle bounce
• Particle shape

Particle straining:

Particle straining is concerned with the general perception that filtration is a simple process of straining (sieving). Straining (which has been discussed at length in earlier parts) occurs when a particle in the feed is larger than the pore or constriction (space) through which it is attempting to pass [6].

When we think about the process of filtration, our mind typically thinks of the process of straining tea leaves through a strainer as an immediate and empirical analogy, as shown in Figure 2. However, there is more to the mechanism of filtration than meets the eye. It involves complex processes, like inertial impaction, interception and diffusion play, which collectively impact the process of particle removal. Figure 3 illustrates a very good example of how the entire gamut of ‘capture mechanics’ operates simultaneously. It shows how particles smaller in size than that of the pores were captured around filter fibres, although from the standpoint of size, they could have passed through the highlighted larger pores. This only goes to highlight the fact that the straining mechanism is not the dominant mechanism in in-depth filtration, and it is certainly not how the entire filtration process operates.

Particle bounce:

Technically, a particle is considered filtered when it is both separated and retained on or within the filtration media. This fundamental concept requires a detailed investigation, not only by addressing the capture mechanisms of particles but also by considering how particles collide with fibre surfaces and, therefore, are re-entrained into the airstream to lower the overall efficiency of the filter. One of the general assumptions is that a particle will remain captured after it comes in contact with a fibre surface. But in reality, particles can, in fact, bounce after colliding with the fibre surface. The possibility of this occurring depends on particle composition, shape, velocity and the type of impaction surface. Particles bounce away from the fibre surface, as illustrated in Figure 4, if the rebound energy exceeds the adhesion energy. Three salient factors can contribute to this effect [1]:

1. Harder materials comprising the particle and surface
2. Larger particle size
3. Higher particle velocities

Particle shape:

When we think of particles, we are quick to assume that all particles are spherical. In fact, particles are mainly non-spherical, as shown in Figure 5. The behaviour of the aerosol particle is highly influenced by its shape, size and density. These characteristics can determine the dominating filtration mechanism. Particle shape, for example, influences various processes, such as the drag force in a resisting fluid, light scattering or electrical charging. The separation technique of air filters, therefore, requires an exact definition and assessment of particle sizes that is required to be filtered. Also, the removal of particles from a gas stream by the impaction mechanism is very sensitive to the drag force [7].

Solid particles have the most varied shapes, and coagulate to form aggregates. The irregular shape of particles results also from the crystalline nature of the primary material.

NA Fuchs [8] defined the particles from a shape-standpoint into three classes:

• Isometric such as spherical particles
• Particles with one of their dimensions being smaller than the other two, such as flakes and disks
• Particles with one dimension larger than the other two dimensions, such as needles or fibres

Pollen grains

Pollen grains are not as simple as they appear to be. They are discharged by weeds, grasses and trees, and can cause hay fever [9]. Once airborne, they immediately become a filtration concern, as they can be inhaled and can reach the sensitive nasal passages. Most pollen grains are hygroscopic and, therefore, vary in mass with humidity [10]. An inhaled count of 10 to 25 may make those who are prone to hay fever, experience the first symptoms [10]. Figure 6 shows a pollen grain deposited on the surface of a used filter media in the GCC region of the size of nearly 50 μm. On the other hand, Figure 7 shows a pollen grain found on a European Daisy, ranging in size between 20 to 25 μm. These two images highlight the differences in particle size and shape as well as illustrating pollen deposition after being airborne, as also daisy pollen grain at the source.

Realistically speaking, we don’t need a 500 Hp car to go to work. And by the same token, we don’t require a high-efficiency filter to remove pollen grains from the airstream, as this can easily be done by means of a pre-filter. Therefore, straining pollen grain on the surface of high- efficiency filter is simply a waste of both its surface and its depth.

Accepting responsibility

When a serious thought is given to various contaminants that either go through or bypass filters to reach our lungs, one apprehensively begins to wonder if filtration is the last remaining friend of our respiratory system. The question then is: Are we taking the lead in investigating source control measures to reduce dust particle emission? The corollary that logically follows is: What measures or even initiatives have been set forth to provide clean air to humanity?

Undoubtedly, we need to face the truth and embrace responsibility to ensure that air filters and HVAC systems are ready and capable of removing harmful contaminants. Not only our innate humanity, but even plain common sense dictates this. It is time we accept the necessary moral and practical engagement needed to protect humans, whether they live in incubators, daycares, kindergartens, schools, homes or offices. All of us can contribute to a better environment, no matter what vocation we are engaged in. Since life depends upon air, we certainly cannot insouciantly breathe it without granting its quality the required attention and care, taking appropriate measures.

The writer is Regional Director, Middle East, and International Consultant, EMW Filtertechnik, Germany. He can be contacted at iyad.al-attar@emw.de

IMPORTANT NOTE: Unless otherwise referenced, the images used in this article are copyright of the author

References:

[1] Hinds WC, 1998. “Aerosol Technology”, Wiley, New York.

[2] Zhang, Yuanhui, 2005. “Indoor Air Quality Engineering” CRC Press LLC.

[3] Parker, Steve, 2007. “The Human Body Book”, Dorling Kindersley Limited, New York.

[4] NAFA, 2001. “Guide to Air Filtration”, Washington, DC: National Air Filtration Association.

[5] Brimblecombe, P, 1996. “Air, Composition and Chemistry”, Cambridge Environmental Chemistry Series 6, 2nd ed, Cambridge University Press.

[6] Tarleton ES and Wakeman RJ, 2008. “Dictionary of Filtration and Separation”, Filtration Solutions, Exeter.

[7] Murphy CH, 1984. “Handbook of Particle Sampling and Analysis Methods”, Verlag Chemie International, Inc.

[8] NA Fuchs, 1964. “The Mechanics of Aerosol, Pergamon”, New York.

[9] Jacobson AR and Morris SC, 1997. “The Primary Pollutant, Viable Particulates, Their Occurrences, Sources and Effects in Air Pollution”, 3rd edition, Academic Press, New York.

[10] ASHRAE, 2001. ASHRAE Handbook: Fundamentals. Atlanta, GA: American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc.

Light-emitting diode, or LED lighting is a preferred choice of illumination in most new constructions compared to traditional incandescent bulbs. The obvious advantages LED lighting offers clearly tips the balance in its favour: It has a longer lifecycle, thus minimising the need for frequent replacements and putting pressure on landfills; it does not use mercury, a hazardous substance; it is energy-efficient and cost effective. To put it succinctly, it has a positive impact on energy bills and the environment.

Viewed from the HVACR standpoint, this translates into a major step forward for the sector. LED lighting emits light without the attendant heat. In fact, experts claim that LED fixtures emit as much as 95% less heat than their traditional counterparts. This reduces the heat load in a building, thereby reducing the pressure on air cooling systems, which consequently, consume fewer units of energy. This dramatically brings down the cost of running air conditioning systems. Apart from individual benefits to end users, building owners and real estate developers, it is also beneficial to the retail and the hospitality sectors. More significantly, it has a far-reaching ecological impact. A drastic reduction in carbon emission leads to corresponding reduction in carbon footprint of buildings, and, ultimately, global warming.

Given the demonstrable environmental benefits, the hospitality industry, in particular, with its constant operational demands has a significant potential to make large energy savings by switching over to LED lighting. Currently, 42% of energy usage comes from lighting, of which 70% is inefficient. Closer to home, reportedly, approximately 22% of the electricity used in the Middle East is spent on lighting, which is a higher rate compared to the rest of the world.

Seen in this light, Illuminesca, dedicated to LED, was an event aimed to raise awareness about new lighting solutions. The underlying purpose was to prove in real time through live demonstrations, why LED was a sustainable alternative in the long run. Organised by the Royal Philips Electronics, it was held on March 14 at the Dubai Festival City’s Intercontinental Hotel, and attracted stakeholders like engineers, architects, designers and management of hotels, malls and supermarkets. The event reportedly showcased the company’s latest retail and hospitality LED lighting innovations, which lay claim to reducing carbon emission, saving energy and lowering operational costs.

Introduction

Since the 1989 Montreal Protocol and its successor agreements have come into being, the world of refrigerants has been marked by change. In its search for more environmentally friendly refrigerants, technology has moved from chlorofluorocarbons to a host of alternative substances. Many of these substances serve as interim measures, until the phase-out of ozone-depleting and global-warming refrigerants meet the targets set by the US Clean Air Act. The journey towards compliance has caused the HVAC equipment and appliance industries to revisit the potential use of substances that have good environmental and thermodynamic properties as refrigerants, but which are also, unfortunately, flammable.

An increased use of flammable refrigerants in the US?

It may be surprising to learn that the first commercial refrigerant was a flammable refrigerant. In 1850, an ethyl ether vapour compression system for ice making was developed. From that humble beginning of freezing a simple pail of water, a robust vapour compression refrigeration industry was developed.1 Today, ice-making alone is a nearly one billion-dollar industry in the US. Along the way, scientists, engineers and probably more than a few tinkerers2 have experimented with numerous potential refrigerants.

Ammonia (R717) was an early choice for breweries and continues to be a popular refrigerant in industrial applications, including food processing, pharmaceutical and, even today, breweries.3 Noxious, but non-flammable sulphur dioxide (R764) became popular for small refrigerating systems, and was in widespread use in the US into the 1940s.4 Methyl chloride (R40) experienced brief popularity, but its flammability and potential toxicity ultimately made it unsuitable as a refrigerant. Propane (R290) was touted as a replacement for ammonia refrigerant in the 1920s.5 Isobutane (R600a) was first used as a refrigerant for small systems in the 1920s, but as with other flammable refrigerants (except ammonia), it quickly fell out of use when chlorofluorocarbon (CFC) refrigerants were introduced for commercial use in 1931.6

CFCs had a 60-year run as the refrigerants of choice, until they were identified in the late 1970s as ozone-depleting substances. The phase-out of CFC refrigerants began a little over 10 years later.

A mature safety system had evolved over the decades, as various industries settled upon refrigerants which were generally non-toxic and non-flammable, which provided consistent performance, and which were relatively inexpensive.7 Household refrigerators used the CFC R12. Larger commercial refrigerators used another CFC, R502, while air conditioners used R11 (CFC) and R22 (HCFC). Manufacturers ensured that their equipment was appropriately designed and constructed using well-established criteria and standards, chose the correct refrigerant for the application, and then sold the equipment for installation and use in accordance with equally well-established standards and codes.

However, beginning with the phase-out of CFCs, the choice of refrigerant has increasingly become a complicating factor in equipment design, construction, installation and use. In the US, the widespread use of pure hydrocarbon refrigerants, flammable hydrocarbon refrigerant blends, or halo-hydrocarbon blends with flammable hydrocarbons has further complicated matters.

Challenges posed by flammable refrigerants

Vapour compression refrigeration in appliances is a closed system that circulates a volume of refrigerant and lubricant under pressure. This system typically operates under variable environmental conditions, and often must be capable of adjustment to meet the end-use application. From a traditional electrical equipment safety perspective, (electric shock, fire and casualty hazards), appliance designers have sought to reliably contain the refrigerant. To accomplish this, they have used tubing, vessels and other components with sufficient mechanical strength to handle the developed pressures under expected normal and abnormal operating conditions.

Because the typical HVAC and appliance refrigerant gas (excluding ammonia) was non-toxic in the volumes used and non-flammable, the potential for gas leakage or explosion was not considered to be a safety concern, except under fire conditions. In such cases, the refrigerant system was required to have a means for the controlled venting of refrigerant, before pressure build-up could cause an explosion hazard.

Aside from locations where large quantities of refrigerant might be found (for example, large commercial/industrial facilities), there has been limited concern for the safety of refrigerant-containing appliances in all manner of occupancies.8 This would include locations where a number of appliances are stored or used (for example, warehouses, retail locations)’9 or how the appliances are transported, serviced or disposed of. However, if a flammable refrigerant were to be used in these appliances, it cannot be assumed that safety is adequately assured.

Hydrocarbon refrigerants (HCs) present a risk of fire and explosion hazard if there is a refrigerant leak. The vapour within the closed refrigeration system is not flammable until oxygen is present at the location of the leak, or in the location(s) where the hydrocarbon gas travels after leaking from the system. If the gas and air mixture is within the upper and lower flammability limits (UFL and LFL respectively)10 for the particular refrigerant, the mixture is flammable in the presence of an ignition source. Hot surfaces11 and electrical arcs, such as those present at the contacts of electrical switching contacts (switches, temperature and humidity controls, etc.), are the principal potential ignition sources in HVAC and appliances.

The same concerns hold true for other flammable refrigerants, as well as for refrigerant blends containing flammable refrigerant components. The presence of a flammable gas and air mixture from a leaking refrigerant blend additionally depends upon the properties of the blended gases, and whether they separate into individual component gases (fractionate).12

Small quantities of flammable refrigerant discharged into an open area may disperse at a rate that ensures that the LFL is not achieved or is achieved for a very brief time period. However, for larger quantities of refrigerant, or in situations in which the leaked refrigerant is contained in a smaller volume space, or in which the leaked refrigerant accumulates (for example, heavier-than-air refrigerant), it is more likely that the LFL can be reached and sustained.

Supermarket refrigerated cases and building air conditioning systems typically have larger quantities of refrigerant. Because these systems are often assembled on-site, they are more often subject to leaks.13 Indeed, leakage is regarded as a given for field-assembled equipment. The Clean Air Act now requires refrigerant leaks to be repaired for systems containing over 50 pounds of refrigerant if the leakage is determined to be 35% or greater in a 12-month period for commercial refrigeration, and 15% for comfort cooling and other appliances.14 Therefore, the use of a flammable refrigerant in such equipment would require improved containment features over those found in non-flammable refrigerant systems. It would also require mechanical ventilation and other mitigation procedures at the installation site to avoid the presence of a flammable gas and air mixture at potential ignition sources, either on the equipment or in the installation environment.

Smaller equipment, such as household refrigerators can also leak. Improved containment over non-flammable refrigerant systems is also appropriate, but mechanical ventilation or other means to disperse the refrigerant may not be practical for such appliances. Equipment designers must then look to avoid placing potential ignition sources in locations (for example, a storage compartment, hollow in a wall, etc.) that could yield a flammable gas and air mixture in the event of a leak. The designer, of course, can often do little about other possible ignition sources in the installed environment.

All equipment is serviced and, ultimately, disposed of. These activities also are potential situations for leakage. The equipment design must minimise the risk of fire or explosion during servicing, and service personnel must have sufficient knowledge to safely do their job.

Upon disposal, the refrigerant should be recovered, though relatively small propane or isobutane refrigerant charges could conceivably be released to the air in a controlled manner.15 Parties involved in the disposal of HVAC equipment and appliances should also have sufficient knowledge to perform their job safely, and should be able to identify equipment with a flammable refrigerant charge. For their part, equipment designers must anticipate the need to evacuate the refrigerant from equipment upon disposal and to facilitate identification of locations on the equipment intended for this purpose.

Most appliances, room HVAC equipment and split systems are factory charged, and subsequently transported with the charge present, and may be transported multiple additional times throughout the product’s useful life. Vehicle transport can jar or vibrate the parts containing refrigerant, increasing the risk of leakage. Designers must account for these concerns in the equipment design, as well as the equipment packaging.

If an individual appliance has a small refrigerant charge, but there are many such appliances at a given location (eg, a warehouse or tractor-trailer), the aggregate amount of flammable refrigerant may be relatively large. Though it is unlikely under normal circumstance that all of the appliances might simultaneously leak, a warehouse fire or transportation accident could lead to the leakage of large volumes of flammable refrigerant.

While the risk conditions noted above can often be anticipated in the design process, it is much more difficult to anticipate the abuse of equipment in use, and to design appropriate safety features to mitigate that risk. For example, vending machines are checked for the risk of overturning in cases where the equipment is rocked back and forth to dislodge a vended product. But what type of rocking test would adequately assess the risk involving a vending machine with flammable refrigerant? It can also be a challenge to ensure that an installation site doesn’t pose an unacceptable risk. For example, how can local building authorities anticipate and address the potential risk posed by having multiple appliances containing flammable refrigerant in a single-family residence or in a children’s play area or classroom?

Figure 1 (click on image)

These and similar such concerns involve a number of potential stakeholders who individually and collectively have a key role in ensuring the safety of HVAC equipment and appliances containing flammable refrigerants. As the publisher of equipment safety standards for HVAC equipment and appliances, Underwriters Laboratories Inc (UL) has identified stakeholder interests that it believes to be relevant to the total safety system, in which safety standards are an essential element. These areas of interest are depicted in Figure 1.

Stakeholder identification is just a first step in undertaking a unified and coordinated review of the potential impact of the wider use of flammable refrigerants in HVAC equipment and appliances. Gaps in codes and standards for installation and use, including the applicable equipment safety standards, need to be identified and addressed. Education and training for installers, service personnel, storage and retail facilities operators, fire fighters and inspection professionals will also be important.

The remaining parts of this paper will explore the most important factors that are expected to result in flammable refrigerant HVAC equipment and appliances, the current state of safety standards, and some near-term activities to address the gaps.

- Thomas Blewitt is Director of Primary Designated Engineers, Underwriters Laboratories and can be contacted at: Thomas.V.Blewitt@ul.com
- Abhay Miglani, is Business Manager, India, Middle East & Africa, Underwriters Laboratories and can be contacted at: Abhay.miglani@ ul.com

References:
[1] [1] CFC’s: Time of Transition, ASHRAE, 1989, p 4.
[2] Individuals experimenting with refrigerants outside of university and corporate laboratories are not just a thing of times past. Hawaii News Now (hawaiinewsnow. com) reported in a June 20, 2008 article by Howard Dashefsky that auto mechanic Richard Maruya of Kaneohe, HI developed the hydrocarbon refrigerants HCR 188 and HCR 188c in his garage using off-the-shelf materials. These refrigerants are currently out for public review for recognition under the EPA SNAP Program.
[3] Ammonia Refrigeration Products and Services, “What is Ammonia Refrigeration,” by Renewable Energy institute,http:// ammoniarefrigeration.net/.
[4] CFCs: Time of Transition, ASHRAE, 1989, p 9.
[5] Ibid, p 11.
[6] Ibid.
[7] For example, R12 was so inexpensive that it was commonly used as an aerosol propellant in consumer products such as hairspray.
[8] This observation is based on the appliance being used and installed as intended by the manufacturer and does not take into account environmental concerns or abuse (eg refrigerant “huffing”).
[9] This observation doesn’t take into account the potential exposure to byproducts of combustion that may be present in a building fire.
[10] From UL 250 Table SA5.1 Refrigerant lower flammability limit (LFL): 2.1% for propane (R290), 1.5% for n-butane (R600), 1.8% for isobutane (R600a).
[11] From UL 250 Table SA5.1 Refrigerant ignition temperature: 470oC for propane, 365oC for n-butane and 460 oC for isobutane.
[12] This is a simplification of what can be a complex circumstance. Other factors, including compressor motor lubricants, the nature of the leak and ambient environment, among others, can affect the risk that a flammable gas and air mixture is present.
[13] Historically, “the average (commercial) refrigeration system loses its complete refrigerant charge three times in 10 years,” according to“The True Cost of Refrigeration Leaks,” Esslinger, S., “CFC’s in Transition,” ASHRAE, 1989, p 235.

Background

The Organisation of Petroleum Exporting Countries (OPEC) expects that around 150% more energy will be needed by 2032 compared to today. The growing demand also means higher oil prices, and, therefore, higher costs for the users. The issue of heating costs, in particular, puts great pressure on companies. They need energy for water heating, for air conditioning in offices and workrooms or for manufacturing processes.

Heat pumps constitute one possibility for efficient management of necessary heat energy. Energy can be saved, in particular, by those applications that are coupled to heat recovery from industrial processes. Waste heat generated in this way can be put to profitable use in the building – a potential that was scarcely used for a long time. “Heat pumps, operated with natural refrigerants such as ammonia (NH3), are also particularly environment-friendly,” remarks Thomas Spänich, Member of the Board at Eurammon, the European initiative for natural refrigerants. “In contrast to synthetic refrigerants, they have either no or only a negligible global warming potential. Heat pumps with natural refrigerants are already being used for cost- and energy-efficient operation. They can be planned and implemented individually, depending on the requirements of the particular building and the customer’s specific needs. The market for heat pumps can, therefore, expect to see further strong growth in the near future.”

Energy-efficient district heating for Sarpsborg, Norway

GEA Refrigeration Germany developed a completely new 2 MW heat pump installation for the energy provider Bio Varma Sarpsborg AS in Norway to heat water up to +82°C for the municipal district heating network. The heat pump uses two different waste heat sources to keep energy costs as low as possible. 1.5 MW of power comes from re-cooling +45°C warm cooling water from a refrigeration system serving the municipal waste incineration plant, with a further 3 MW supplied in the form of +38°C warm water from a biological sewage plant.

Initially, the water is heated using the hot oil in the oil separator. But most of the work is performed by the condenser at a condensation temperature of +82°C maximum. The last few degrees then come from a superheater fed by +105°C hot gas on the jacket side.

For the first time, this kind of system has been equipped with two large oil filters and an oil pump with an 18.5 kW motor capable of pumping about 900 l/min. GEA has also provided a 1,200 kW high-voltage motor and a frequency converter for motor and oil pump. The centrepiece of the system consists in an R-series high-pressure compressor. However, the high-pressure side of the system had to be rated for a pressure level of 52 bar on account of the high condensation temperatures. This resulted in the need for new components, pipes and mouldings to be procured, and in some cases, even specially designed. The system started operating in September 2010, and has been running perfectly ever since.

Combined cooling and heating in Fleischtrocknerei Churwalden (meat drying plant), Switzerland

Fleischtrocknerei Churwalden AG produces organic quality meat products. Environment-friendly production is part of the corporate philosophy. This also includes ecological efficiency of systems and premises. The refrigeration professionals from SSP Kälteplaner developed a sustainable heating and cooling system for the meat-processing centre in Landquart, Switzerland, using heat pumps and refrigerating machines that run on the natural refrigerants, ammonia and carbon dioxide.

The central aspect of heat generation and refrigeration consists in making active use of the groundwater stream of the Alpine Rhine plain. Catchments and groundwater pumps take water from the groundwater stream and then return it in thermally changed state. The energy gained in this way – refrigerating or heat energy, as required – is brought to the required temperatures by refrigerating machines and heat pumps for a wide range of uses.

The production and administration buildings need thermal energy at different temperatures. Heat energy of altogether around 950 kW is needed on two different temperature levels: at medium temperatures of about +60°C as process energy, among others, for climatic chambers, hot process water or container washing machines, and at lower temperatures of up to +40°C as heat energy for heating purposes, for dehumidification, for pre-heating hot process water and for defrosting the cold storage rooms.

A refrigerating plant capacity of 1,200 kW is needed for maintaining temperatures around freezing point for workrooms, and also for temperatures of -8°C in chilled storage rooms and maturing plants, as well as temperatures of -25°C in the deep-freeze storage rooms.

A two-stage ammonia heat pump is used for heating purposes according to the different temperature levels, using groundwater at +12°C and +8°C. Each stage is fitted with two York/Sabroe reciprocating compressors, which are regulated in a stepless manner by frequency changers. Cassette-welded plate heat exchangers by Alfa Laval are used as evaporators and condensers. The ammonia charge in the heat pump amounts to approximately 300 kilogrammes. The production systems are rated for temperatures in the medium range of +60°C. The motor waste heat and compression heat from the compressed air and vacuum generation system is fed directly into the system, while the ammonia heat pump generates the necessary remaining energy. The ammonia heat pump also plays a supportive role at the lower temperature level of +40°C and generates the necessary remaining energy. The “warm” groundwater basin acts as heat source.

Consistent use is made of any generated waste heat. Where possible, it is fed directly into the heat distribution system and distributed again immediately. This is used for cooling motors, including those used, for example, for generating compressed air or in the central vacuum system. Waste heat on the lower level is dissipated into the “warm” groundwater basin. This includes condensation waste heat from the refrigeration and tool cooling at the packaging machines in the framework of the cooling water circuit.

Two ammonia refrigerating machines are responsible for refrigeration and are cooled with groundwater. After cooling, the water is fed to the “warm” groundwater basin. When the need arises, the heat pump can bring the waste heat from the basin up to a higher temperature. Refrigerating energy of 0°C and -8°C is generated in each case by a refrigerating machine using NH3 as refrigerant and two industrial reciprocating compressors. One of the respective compressors in each case is equipped with a frequency changer. The energy is transported to the refrigeration sites using a water/glycol blend as secondary refrigerant. The recooling energy is taken from the “cold” groundwater basin. Exchanging the water from the heat pump to the refrigerating machine and vice versa achieves maximum efficiency ratios, while keeping the drive motors and refrigerant circuits as small as possible. Buffer storage facilities with a volume of 30,000, have been installed for both secondary refrigerant networks in order to optimise operations.

The natural refrigerant carbon dioxide is used in the deep-freeze storage rooms. The refrigerant is evaporated directly with electronic expansion valves in the room chillers, before passing to the reciprocating compressor, where it is liquefied to subcritical state in a cascade condenser. The waste heat from the systems is dissipated to the glycol network at a temperature of -8°C where the heat can be put indirectly to further use.

In summer, needed cooling energy is taken from the “cold” groundwater basin and used directly for room cooling in ventilation systems, cooling ceilings or in server rooms. Apart from the pump conveying energy, no primary energy is used for air conditioning refrigeration.

Heat pump supplies chocolate factory with hot water free of cost

In 2010, refrigeration professionals, Star Refrigeration, won an order from Nestlé to develop a heat pump solution for a chocolate factory in the British branch in order to bring about significant reductions in the energy costs for refrigeration and heating applications. It replaced existing R22 packaged chillers and a central coal-operated steam generation unit, which supplied all terminal devices and systems using and dissipating hot steam during their work processes. The new concept entailed taking waste heat from the cooling circuit and boosting it to provide process water heating up to the required temperature. Star Refrigeration’s “Neatpump” heat pump was to provide water up to a temperature of +60°C which was to be fed as preliminary heat also to processes needing higher temperatures.

Given the food manufacturer’s commitment to keeping its carbon emissions as small as possible, environment-friendly heat pump technology had to be used here. But apart from the fact that heat pumps were still mainly operated with HFCs, for the most part any system using natural refrigerants uses reciprocating compressors or screw compressors, which cause high maintenance costs or worked constantly at their limit.

In cooperation with Vilter Manufacturing, USA, and Cool Partners, DK, Star Refrigeration developed a high-pressure heat pump solution that works both with ammonia as an environment-friendly, highly energy-efficient refrigerant and also with screw compressors to a temperature of +90°C. The system offers a convenient solution for extracting the waste heat at -5°C from the glycol as the secondary refrigerant from the refrigeration process, and raising this to the main heating demand at +60°C.
A new gas-fired boiler is used to increase the +60°C water temperature for a number of smaller heating demands on site.

The heat and refrigeration load profiles of the existing systems ascertained in advance showed that the heat pump compressors had to generate about 1.25 MW of high temperatures to satisfy the total demand for hot water. The new solution was, therefore, chosen with 914 kW refrigeration capacity and 346 kW absorbed power rating from the waste heat. The COP in the framework of combined refrigeration/heating application (COPhc) is a moderate 6.25. The additional energy required to raise the condensing temperature from design summer ambient conditions with air cooled condenser to a temperature suitable for +60°C hot water production was only 108 kW. This resulted in an incremental COPhc (energy to create +60°C water minus energy to reject cooling load heat at design conditions) of 11.57.

Using the waste heat from the refrigeration applications has paid off for Nestlé: Since starting operations in May 2010, the system uses and heats around 54,000 litres of municipal water per day, thus saving around £30,000 in gas costs each year. Since the end of 2010, the site has also been using a further 250 kW in waste heat for its self-contained cooling circuits. The heat provided by the system also doubled by the middle of last year. In this way, the company saves an estimated approx. £143,000 in heating costs while reducing its carbon emissions by 119,100 kilogrammes. Moreover, the costs for electrical operation of the plant are reduced by around £120,000 per annum, despite combined refrigeration and heat generation.

Heat pumps with natural refrigerants on the advance

Heating and energy consumption are topics of interest not just for the industry: Home owners are also on the lookout for suitable technologies for keeping overheads as low as possible and saving energy. “Hot water heat pumps using CO2 as refrigerant, are particularly interesting,” says Spänich. “They can make full use of the characteristics of the supercritical refrigerant process. Optimum adjustment to the heating up process permits excellent performance ratios with very high water output temperatures of up to +90°C in some cases,” the member of the Eurammon Board continues. “In Germany, this solution has hitherto seen only isolated use. By contrast, in Japan the Japanese Government subsidises purchases of CO2 heat pumps so that around two million units were sold throughout the country already by the end of 2009. This number should reach 10 million by 2020.”

Annex Carbon dioxide (CO2) Carbon dioxide is known in refrigeration technology as R 744 and has a long history extending back to the mid-19th century. It is a colourless gas that liquefies under pressure, with a slightly acidic odour and taste. Carbon dioxide has no ozone depletion potential (ODP = 0) and negligible direct global warming potential (GWP = 1) when used as a refrigerant in closed cycles. It is non-flammable, chemically inert and heavier than air. Carbon dioxide has a narcotic and asphyxiating effect only in high concentrations. Carbon dioxide occurs naturally in abundance. Ozone Depletion Potential (ODP) The ozone layer is damaged by the catalytic action of chlorine, fluorine and bromine in compounds, which reduce ozone to oxygen and thus destroy the ozone layer. The Ozone Depletion Potential (ODP) of a compound is shown as chlorine equivalent (ODP of a chlorine molecule = 1). Global Warming Potential (GWP) The greenhouse effect arises from the capacity of materials in the atmosphere to reflect the heat emitted by the Earth back onto the Earth. The direct Global Warming Potential (GWP) of a compound is shown as a CO2 equivalent (GWP of a CO2 molecule = 1). Ammonia (NH3) Ammonia has been successfully used as a refrigerant in industrial refrigeration plants for over 100 years. It is a colourless gas, liquefies under pressure, and has a pungent odour. In coolant technology, ammonia is known as R 717 (R = Refrigerant) and is synthetically produced for use in refrigeration. Ammonia has no ozone depletion potential (ODP = 0) and no direct global warming potential (GWP = 0). Thanks to its high energy efficiency, its contribution to the indirect global warming potential is also low. Ammonia is flammable. However, its ignition energy is 50 times higher than that of natural gas and ammonia will not burn without a supporting flame. Due to the high affinity of ammonia for atmospheric humidity, it is rated as “hardly flammable”. Ammonia is toxic, but has a characteristic, sharp smell, which gives a warning below concentrations of 3 mg/m³ ammonia in air possible. This means that ammonia is evident at levels far below those which endanger health (>1,750 mg/m³). Furthermore, ammonia is lighter than air, and therefore, rises quickly.

References: http://www.opec.org/opec_web/static_files_project/media/downloads/publications/WOO_2011.pdf

In the last few years, many conferences focusing on the topics of sustainability and energy efficiency have taken place across the region.

However, the first round of Refrigerants Review was unique in many ways. First, because, as the title suggests, it was the first time that a dedicated event on the issue of ozone-depleting and high global warming potential substances gathered a plethora of global refrigeration experts in Dubai.

Secondly, because the debate showed that HFCs phase-out or, better said, phase-down, is a very complex issue, where there is no right or wrong answer.

Furthermore, the event highlighted that, when examining the ODP (Ozone Depletion Potential) and GWP (Global Warming Potential) of a particular refrigerant, it is fundamental to take into account the overall energy efficiency of the system in which such a refrigerant is used.

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Hence, over the last few years, the concept of LCCP (Life Cycle Climate Performance) have gradually gained ground, as a more comprehensive assessment tool, representing the cradle-to-grave environmental impact of using a given refrigerant in an application throughout its life cycle.

The presentations also reflected on the fact that the use of refrigerants encompasses the whole global supply chain, and it’s not only limited to air conditioning or heat pump applications, but, for example, it is also essential in food preservation, particularly in this part of the world, where high-ambient conditions represent a key challenge to the proper storage of easily deteriorating produces, such as fruits and vegetables.

Indeed, as Dr Stephen O Andersen, Director of Research, Institute for Governance & Sustainable Development (IGSD) and Co-Chair, Montreal Protocol Technology & Economic Assessment Panel (TEAP), pointed out in his keynote address on Day 1 of the conference, “many countries face high temperatures, but few other places on Earth are as challenging as the long, hot, and sometimes humid conditions of Africa, India and the Middle East”.

In his view, some regions, like the Middle East, face a number of inherent challenges, such as a long, hot and humid cooling season, “brown-outs” and other electricity quality problems, high energy cost and low equipment durability.

Dr Andersen described the 1987 Montreal Protocol, aimed at phasing out the production of numerous substances believed to be responsible for ozone depletion, as a “last-minute treaty”, which saved two-thirds of the ozone layer.

“Without the ozone warning by Mario Molina and Sherry Rowland [in 1974], the emissions of ODS would be as big a force in climate change as carbon dioxide, and the Earth might already have been in a death spiral of abrupt climate change,” he added.

He also argued that CO2 controls are not enough to reverse climate change.

In his opinion, irreversible climate change can be delayed through the use of low-GWP substitutes, along with containment, recovery, reuse and destruction, which further reduce radiative forcing.

“Containment to near-zero emissions mitigates refrigerant ozone depletion, climate forcing, toxicity, flammability, atmospheric fate and price,” Dr Andersen said.

He emphasised that it’s now time to calculate all the aspects of the refrigerants manufacturing process and consider both short- and long-term effects.

This is why it is fundamental to select a refrigerant with superior LCCP, he added.

“Now is the time for new thinking,” Andersen said. “Take climate change seriously, eliminate the direct refrigerant concerns through near-zero emissions and carbon and chlorine offsets and, thereafter, concentrate on energy efficiency.”

He suggested the use of hydrocarbons for household refrigerators/freezers, stand-alone retail refrigerators/freezers, and small room air conditioners; hydrocarbons, CO2 and ammonia for supermarket refrigeration, and, until better options are available, HFC-32 for larger room air conditioners, HFC-1234yf for automobile air conditioning and other HFC-134a applications where natural refrigerants have inferior LCCP, and HCFC-123 for building air conditioning chillers.

In his plenary address on Day 1, Didier Coulomb, Director of the International Institute of Refrigeration (IIR), an independent intergovernmental science and technology based organisation, which promotes knowledge of refrigeration and associated technologies, emphasised the importance of refrigeration, as it covers a wide range of applications, including petrochemical refining, the steel industry, the space industry, nuclear fusion, medicine, air conditioning, the food industry, the energy sector and the environment.

He pointed out that developing and emerging countries are reporting an increasing need for refrigeration, owing to a global population increase, particularly in Africa and South Asia, for an estimated total of 9-10 billion people by 2050.

This will lead to an increased demand for cold chains, particularly in urban areas.

Improved living standards will also favour the use of air conditioning, which in turn, will have a significant impact on the environment.

Coulomb argued that, when selecting a low-GWP refrigerant, it is important to take into account that no refrigerant is perfect, as they all present safety risks and drawbacks, such as flammability, toxicity, corrosion and pressure.

Furthermore, very low GWP refrigerants are still not widely available on the market, although they have been used in Europe in mobile air conditioning applications since the end of 2011 and in experimental studies on supermarkets, which have so far showed encouraging results.

However, a number of safety concerns are slowing down the uptake of natural refrigerants such as ammonia, which is still recognised as the most efficient refrigerant, and propane.

Current research, Coulomb explained, is focused on the development of ammonia-CO2 cascades.

In his opinion, as the market for new refrigerants develops, prices of equipment will gradually decrease, although they will still be 10-20% higher than those of current equipment, but with lower running costs.

In addition, there will be shortage of HCFCs due to the phase out already in force in developed countries, as well as shortage of HFCs produced by very-low-GWP HFC manufacturers.

On the other hand, natural refrigerants will be very cheap, as the higher investment costs are offset by lower running costs.

“Emerging countries will show increasing interest in natural refrigerants,” Coulomb said, pointing to the case of China.

The conference also provided insights into regional thinking on ODP, GWP and TEWI (Total Equivalent Warming Impact) and an understanding of the region’s response to phase-out dates.

Ghaleb Abusaa, CEO of The Three Factors Company (en3), who moderated the session, pointed out that, although HFCs have no impact on ozone depletion, they have higher TEWI than HCFCs as they require more power.

Yaqoub Al-Matouq, a Kuwait-based refrigeration expert, observed that, in 2007 parties to the Montreal Protocol accelerated HCFCs phase-out to support climate change mitigation efforts.

As a result, the industry heavily invested in HFCs as the most reliable alternative to HCFCs.

However, he pointed out, countries with high-ambient conditions, like the Middle East, face major challenges when trying to implement alternative refrigerants.

These include safety (flammability, toxicity, and high pressure), efficiency (as efficiency drops due to high temperatures) and environmental concerns (some refrigerants have high GWP, are not recyclable, and can’t be easily disposed of).

Therefore, he advocated further research into alternative refrigerants as well as further improvements in equipment design to reduce leakages.

Furthermore, he called for unified standards for the whole GCC region to regulate the use of refrigerants in a more effective manner, along with the establishment of an industry advisory board to do research and help regional governments find specific solutions tailored to the climatic conditions of the Gulf countries.

“We need to change the mentality,” he said. “We need a global standard. Why do manufacturers change the specifications to sell equipment in this region?”

Mazen K Hussein, a chemicals expert from Lebanon, elaborated on Stage 1 of Lebanon’s HCFCs phase-out management plan (HPMP) for compliance with the 2013 & 2015 control targets of the Montreal Protocol.

As he explained, the HPMP comprises a combination of technology transfer investments, technical assistance to the industrial sectors, training programmes, policies and regulations, coordination and monitoring, and awareness, communication and management.

Hussein claimed that, successful completion of Stage 1 will result in net sustainable reductions of minimum of 20.03 ODP tonnes in the national HCFCs consumption by 2015, as well as net CO2-equivalent emission reduction of about 0.66 million tonnes annually from 2015.

The country will initially target the air conditioning and foam sectors, where mature and sound alternatives are available, focusing on enterprises with solid financial standing and market reputation as well as larger HCFCs consumption.

Within the air conditioning sector, the plan aims at replacing HCFC-22 with R-410A, while it will facilitate the replacement of HCFC-141B with pentane in the foam industry.

Hussein said that the second stage of the plan (2015-2022) will focus on the phase-out of the residual HCFCs consumption in the manufacturing sectors which could not be addressed in Stage 1, as well as reduce HCFCs consumption in the servicing sector.

It will also include sustained monitoring and enforcement of the regulations issued during Stage 1.

Narciso M Zacarias, Principal Engineer ̶ Air Pollution at Dubai Municipality, illustrated Dubai Strategic Plan 2015, which also addresses the issue of HCFCs phase-out.

As he explained, as part of DM green building regulations and specifications, in all new buildings, refrigerants with zero ODP and less than 100 GWP must be used.

Furthermore, the venting or direct discharging of any refrigerants during equipment maintenance is strictly prohibited.

In addition, recovery, recycling and reclaim of refrigerants for high-temperature and medium-temperature applications should be practised at all the times.

This service, Zacarias said, is provided by companies like Environserve.

Zacarias also pointed out that Dubai Municipality is fully committed to the tracking and monitoring of illegal refrigerants’ imports and exports to and from the country and across borders, and is planning to step up its efforts over the coming years.

The first day of the conference also featured presentations by regional and international industry representatives, who shared their views on current HCFCs phase-out policies.

The session was moderated by Rajendra Shende, Former Director of UNEP and Chairman, TERRE Policy Centre.

Torben Funder-Kristensen, VP, Public and Industry Affairs, Danfoss A/S Denmark – Danfoss Refrigeration and Air Conditioning Controls, pointed out that TEWI, which includes both direct and indirect emissions, is the most important parameter to assess the actual environmental impact of a given refrigerant on global warming. Therefore, its reduction is fundamental to fight climate change.

He acknowledged that the purchase cost of a product is important, although the life cycle cost (LCC) is becoming even more important, as it is directly linked to LLCC.

“We encourage investment in low ODP/GWP refrigerants,” he said.

However, he also stressed the fact that, in order to achieve long-term sustainability goals, it’s essential to take into account and balance all parameters, such as low GWP, comfort, service, safety, affordability and efficiency rather than optimising only one of them.

Funder-Kristensen added that his company is currently focused on improving energy efficiency and further developing natural refrigerant solutions.

Fadi Hachem, Head of District Cooling Division of DC PRO Engineering, addressed the current challenges faced by the district cooling industry as a result of HCFCs phase-out.

He explained that the district cooling Industry in large scale projects utilises electric driven centrifugal chillers of 2,000-2,500 TR nominal capacity.

To date, these chillers primarily use HFC refrigerant R134A and HCFC refrigerant R123.

Hachem claimed R-123 refrigerant is a low pressure refrigerant leading to lower leakage rates compared to R-134A, especially with the improved automated purge units.

Due to its physical properties, R-123 has a better efficiency rate compared to R-134A when operating under similar conditions. This leads to lower overall energy consumption and an indirect reduction in carbon emissions associated with energy consumption of operating refrigeration equipment.

Therefore, Hachem advocated containment of superior quality HCFCs rather than phase-out.

“The focus should be diverted towards containing [certain] refrigerants rather than phasing them out,” he said.

In his view, this could be achieved through a number of preventive measures, such as provision of proper storage facilities to minimise losses during machine charging and evacuation as required during servicing; provision of machines with the latest high efficiency purging systems; provision of leak detection equipment; training of operation and maintenance personnel in proper handling of refrigerants; enforcement of stringent servicing practices, including log keeping and auditing of the refrigerant annual top up and inventory on site.

Martin Dieryckx, Member of the Executive Board — Daikin Europe and In-charge, Environment Research Centre — Daikin McQuay, warned that by 2050, an estimated 76% of all HFC emissions will come from developing countries. This is why they should be the primary focus of global R&D efforts.

He emphasised that the issue of climate change requires prompt action.

“To avoid global temperature rise, CO2 concentration in the atmosphere must be stabilised at 550 ppm, 450 ppm or even lower (depending on various policy targets),” he said.“The sooner we introduce better alternatives for today’s HFCs, the lower the global warming impact will be.”

He also added that, refrigerant choice varies depending on the application considered.

“There is no one-size-fits-all solution,” Dieryckx pointed out.

The company is developing R32 split air conditioners as, he claimed, “R32 is the most balanced” refrigerant due to a number of characteristics, such as zero ODP, superior energy efficiency, low global warming impact, low conversion cost, moderate flammability and sufficient supply capability.

Dr Nacer Achaichia, Engineering Manager Refrigerants EMEA at Honeywell, discussed the F-Gas regulation review at a EU level, arguing that the key focus should be on emission reduction.

He supported a market-based approach and dialogue with the European Commission, the Member States and other stakeholders.

In his view, the introduction of a refrigerant consumption cap along with phase-down will drive innovation, as emissive applications will convert rapidly to LGWP solutions.

The move will also promote recovery and recycling and recognise the value of HFCs with regard to energy efficiency, safety, environmental performance and total cost of ownership.

Dr Anwar A Hassan, VP, ESG (KSA) and VP Technology at Johnson Controls, said: “Our job is to invest in all viable options and make them available to our clients in proven solid platforms. We do not bet on refrigerants based on short term interest.”

He also pointed out that focusing only on GWP can result in the wrong choices for the environment.

“By far, the indirect effect is much greater,” Dr Hassan claimed. “Depending on the type, service life, and efficiency of the equipment, the indirect effects can account for up to 95% of the CO2 equivalent emissions over the life of a unit.”

Therefore, he said, it’s also important to focus on the energy efficiency of the candidate refrigerants.

Mike Thompson, Global Leader of Refrigerant Strategy — Ingersoll Rand, Trane Commercial Systems, argued that although fluorocarbons cause ODP, GWP or flammability concerns, according to the type selected, some natural refrigerants, on the other hand, pose toxicity, efficiency and cost challenges.

As a result, companies should not be pressured into early phase out, but they should be flexible and keep business interests in mind, preserving the best options for as long as possible.

Furthermore, strong emphasis should be placed on recycle, recovery and reclaim of refrigerants.

Quoting data released by China’s General Administration of Customs, China’s most popular English daily, China Daily, reported that, last February, the country posted its largest trade deficit in the past two decades, US$ 31 billion. While the nation’s imports skyrocketed to 40%, exports only grew at half the rate of imports, registering a 18.4% growth rate year-on-year.

Although analysts attributed the gloomy scenario to “seasonal factors”, such as the Chinese lunar New Year, which fell in January this year, it comes as no surprise that global markets greeted the news with some degree of apprehension.

On January 13, 2012, the China Household Electrical Appliances Association (CHEAA) held a media conference to review the development of the Chinese home appliance industry in 2011.

Output, exports and sales numbers of China’s HVACR sector were released during the conference.

According to CHEAA, the sales of refrigerators dropped by 18%, while the sales of air-conditioners decreased by 12% in 24 Chinese cities in 2011. The growth rate of exports in the sector also declined year-on-year.

The organisation’s growth predictions for 2012 are not looking rosy, either, as exports are expected to slow down due to decline of the US economy, the European debt crisis and stagnation in new markets.

CHEAA expects that, throughout the year, Chinese HVACR manufacturers will be focusing on product upgrading to increase their competitiveness in overseas markets.

China’s key market players include Gree, Midea, Chigo, Hisense, Haier, TCL, Galanz and Aux.

According to Zakir Ahmed, Managing Director at NIA, the exclusive regional agent for Gree products, the latest HVAC technologies available on the Chinese market are inverter compressors for the Residential Air Conditioners (RAC) segment and Variable Refrigerant Flow (VRF) systems and centrifugal chillers for Commercial Air Conditioning (CAC).

Commenting on the allegations that, over the past few years, the country has been favouring economic development at the expense of environmental awareness, Ahmed says “China has the highest Energy Efficiency Ratio (EER) standard for RAC and is pushing for VRF systems and centrifugal chillers for CAC applications.”

The country is also investing heavily in photovoltaics, he adds.

In Ahmed’s view, Chinese HVACR manufacturers are increasingly looking at India, South America and the Middle East as key markets to expand their business.

“No doubt the Gulf is one of the key markets after USA, Japan and Europe. Demand in the Gulf is steady, and the competition is limited to the top three [manufacturers] as others are unable to supply products with T3 specifications,” he says.

Ahmed believes that the main reason behind the growing demand for Chinese products is that “the Japanese vacated space in window and split ACs due to low margins”.

As a result, the Chinese took advantage of this gap in the market.

However, Paul Saunders, Managing Director Fluorines EMEAI at Honeywell, holds a different opinion.

“[It is] simply a matter of economics,” he argues. “As the use of energy-efficient and safe-to-use HFCs grow, Chinese economics can often be attractive. However, customers need to be sure they can get the service level they need and the product quality.”

As he explains, his company has been involved in tracking down the source of counterfeit refrigerants in the UAE and Saudi Arabia.

“On numerous occasions, the source of these counterfeit goods has been clearly Chinese origin,” he claims.

“What is concerning is that often the product inside the cylinder is not even what is reported on the cylinder. Consequently, there are safety and performance issues that can arise from purchasing illegal or fake refrigerants.”

Ahmed, on the other hand, believes that what needs to be questioned is not the quality of Chinese products but rather the lack of standards in the Gulf region.

“Nearly all consumer products sold in the US and Europe are made in China,” he says. “Therefore, the issue is not Chinese quality – it’s the lack of standards in the Gulf. Local traders in the Gulf indulge in unfair competition by forcing manufacturers to cut the costs to the bones.”

He explains that his company has overcome this issue by dealing with well-established brands. “These companies will never compromise on quality to protect their long-term reputation.”

In his view, Chinese HVACR manufacturers have lately shifted their strategy from volume sales to value sales. “They can accomplish this by serving big brands or by promoting their own brands. Alternatively, they will acquire the marketing rights from big brands like Lenovo did with IBM Thinkpad.”

Fabric Air Dispersion Systems (FADS) with a host of new technologies and innovations has come a long way in the last 30 years. It has proved to be functionally superior to traditional ductwork, with regard to Indoor Air Quality (IAQ) and workplace productivity and has added a key element to interior design. The challenge in the sector, however, is to combine diverse elements like consistent fire retardant property, lifecycle, controllability of air dispersion, draft-free comfort and energy conservation.

Fire retardant property

When textile material is substituted with steel ducts, the priority is to ensure that the material used demonstrates consistent fire-retardant property. This can be achieved by the process of post treatment. This involves dipping polyester yarn or fabric into a fire-retardant chemical solution, or laminating a fire-retardant chemical layer on the fabric. Another reliable as well as a superior method is the inherent fire-retardant method. This consists of blending fire-retardant additives with polyester chips, melting and extruding it as yarn and weaving it into a fabric. This results in uniform dispersion of the fire-retardant additive, integral to the polyester body.

Good IAQ demands duct cleaning. The major advantage of using fabric in ducts is that they are washable. However, it needs to be noted that post-coated fabrics tend to lose their fire-retardant property through frequent wash cycles, whereas, the inherently fire-retardant material continues to retain its property despite going through several wash cycles.

Fabric permeability

The fabric used in FADS can discharge air either through the orifices and/or by permeation through the fabric’s pores. The choice of fabric and design of orifices play an important role in prevention of surface condensation, achieving the following:

• Design terminal velocities
• Directing cold supply air distribution to occupied levels
• Avoiding cooling high level spaces

Refrigeration equipment in places like departmental stores consumes a huge amount of energy. Using special fabrics with engineered permeation levels has resulted in energy saving and prevents ice formation, and subsequent malfunctioning of equipment.

It needs to be remembered that when due consideration is not given to choice of fabric permeation at the design stage, it could lead to unstable installation with possible wobbling of ductwork at static pressure or velocities varying from duty design.

Innovations in fabric ducting system

Design and application innovations in FADS give users a wider choice. A few of the options are:

• Fabrics with anti-microbial treatment for areas demanding high-level of hygiene
• Anti-static features for electronic equipment
• Apart from generic shapes like circular, semi-circular and quarter circular ones, they also come in shapes like rectangular-shaped fabrics for lower ceiling heights and smooth tapered ones for long ducts

When we take all the key aspects and advantages of Fabric Air Dispersion System into consideration, it is evident that it is suitable for most applications involving ducted air distribution.

The writer is Assistant Manager, Business Development, BESTPRO, Dubai. She can be contacted at: marian@bestprodubai.com

It is estimated that in the US, nearly 90% of new and existing air systems, in all commercial applications, suffer from varying degrees of leakage. It is also estimated that the average efficiency of these HVAC systems is less than 60%. If the equipment is not served well by its air distribution system, the unit is prevented from reaching the factory-specified efficiency rating that it’s designed to achieve. Some duct closure systems will leak after installation, requiring extra sealant to achieve air tightness.

The four-bolt flange connection system stands out by attaining an airtight seal without requiring additional sealing. This system uses raw duct and applies a heavy-duty flange closure frame, which creates an airtight seal and an easy install for contractors. It consists of four components:

• a connecting flange;
• a reinforcing corner;
• an integral sealant;
• a cleat.

Another advantage is the total weight of the sheet metal required for the ductwork. Other closure systems require the use of a heavier gauge sheet metal, increasing the material and labour cost of the installed finished product. The difficulty with installation of some closure systems makes it troublesome to achieve the airtight seal required. The four-bolt flange connection system allows easy replication of the closure system with some basic training, thus eliminating wasted labour and leaky duct joints. Laboratory tests have shown that a joint made according to the manufacturer’s instructions has no leaks up to a service pressure of ten inches of water gauge.

Using the best closure system achieves overall better quality at lower costs. Without leaks, the unit will require less time to cool or heat a facility, which will use less energy and increase the life of the equipment. With less energy required to obtain the same comfort level, the overall environmental impact of the comfort system is improved. The secondary benefits of lowering pollution, increasing building comfort, and lowering peak demand on the electrical grid make having an airtight seal in the HVAC ductwork a high priority. Properly sealed ducts also keep dust and other airborne particles, which can aggravate asthma and allergies, from building up in the air distribution system.

By choosing the best duct closure system, facility managers and owners can achieve lower installation and operating costs while increasing the effectiveness of the comfort system of their facility.

The writer is Regional Sales Manager, Carlisle HVAC. He can be contacted at john.guthrie@ carlislehvac.com

HVAC controls are broadly distributed into three categories – Chiller Plant Manager (CPM), Building Management System (BMS) and Standalone Airside controls (i.e. AHU controls, FCU controls, VAV controls). These are used in a wide range of applications, including hospitals, shopping malls, oil & gas and non-process buildings.

As Harmandeep Singh, Trane Controls & Contracting Leader, UAE, Qatar, Kuwait explains, overall HVAC system performance is heavily dependent upon operation of the HVAC controls, and, hence, tackling the operational issues is of prime importance.

“Lack of skilled BMS operators, and the frequent changing of FM companies, limit the benefits that can be derived out of an HVAC system,” he points out, adding that “maintenance is less of an issue today, as control systems are more robust, and owners, contractors and FM companies tend to rely on the Original Equipment Manufacturers for their maintenance needs”.

In terms of technical criteria, synchronisation between equipment and controls is fundamental to achieve overall HVAC system performance.

“Controls should be highly reliable, scalable for future expansion, easy to program and operate. They should also comply with UL or CE listing and, for communication purposes, they should be compatible with the industry standard open protocols ̶ for example BACnet, LonTalk & Modbus,” Singh says.

The most common installation issues include interfacing between equipment and controls, with regard to type and availability of signals.

Singh explains that, since HVAC controls installation is usually undertaken by local subcontractors, non-adherence to manufacturers’ recommendations, and quality of locally sourced materials are always a concern.

“For this reason, Trane promotes the concept of factory-mounted controls on Trane equipment, where the installation of controls undergoes the same QA/QC processes as applicable for Trane equipment in the factory,” he says.

This, in his view, saves a significant amount of time spent on installation, testing and commissioning on site, as well as ensures a single-source responsibility for the satisfactory operation of the HVAC system throughout its lifetime.

Singh is confident that the market has entered a phase of strong growth. Part of this, he says, can be explained by the growth in HVAC equipment sales but much more is probably linked to the general acceptance of the fact that controls can bring benefits to installers — in the form of faster installation and commissioning — and end users through easier operation, access to meaningful information and energy savings.

Furthermore, with the increasing influence of local regulatory authorities like Estidama, the standard for HVAC controls is being redefined, and high-quality, energy efficient and environmentally responsible products are becoming popular. “In this transition towards intelligent energy management systems, controls play the critical role of coordinating all the individual elements in a building to ensure that they operate in an optimised manner,” Singh argues.

He believes that the industry is moving away from a first-cost approach and towards value-based decisions. “Installers are increasingly focused on fast, hassle-free installation, testing and commissioning and operators expect user-friendly interfaces, reliable systems and resultant energy and labour savings,” he argues.

Although Singh acknowledges that the slowdown of the district cooling sector has resulted in a shift in focus on energy monitoring and billing systems on the tenant side of the business, he emphasises that integration of power monitoring units and BTU meters into the central HVAC control system is rapidly gaining pace.

Furthermore, installers are also seeing the benefits of factory — fitted controls. “In addition, as the HVAC installations and building stock of the region age, we are seeing more interest in major upgrades and replacements,” he points out. “And once again, controls are playing an important role in delivering operational savings.”

Halton