The abbreviation HVAC (heating, ventilation, air conditioning and refrigeration) includes systems for heating and cooling, for instance in private houses, commercial premises and industrial buildings. Stationary heat exchangers have a broad group of end users. These users are found in the agricultural sector, retail, healthcare, manufacturing industry and in commerical and private real estate, among other sectors.
Increased energy efficiency and performance demands on heating, cooling and ventilation equipment, combined with the continuous quest to reduce manufacturing costs means that the HVAC industry is transitioning to brazed aluminium heat exchangers, to the detriment of the traditional round copper tube plate fin design that has been used for nearly 100 years. The conversion to aluminium heat exchangers is expected to accelerate in the coming years, which will drive growth for Gränges in the HVAC segment.
Residential air conditioners are used to control the properties of air (primary temperature and humidity) in a room or the complete domestic indoor environment. Typically, residential systems consist of an outdoor unit that is connected to one or several indoor units, (reference to the illustrations) in a so-called split or a ductless system.
Brazed aluminium heat exchangers are currently being used primarily in outdoor condensing units, because of their high efficiency, smaller footprint, reduced noise and improved environmental performance. Because these units sit outdoors, withstanding all kinds of operating environments, the choice of materials and combination of alloys for the system are very important.
Commercial HVAC&R systems are generally larger and more complex than residential systems. Such systems may include package or split systems, air handling units (AHU) and/or liquid chillers (reference to illustration). Regardless of the system of choice, brazed aluminium heat exchangers present an ideal solution in commercial applications because of their high efficiency, low refrigerant charge, reduced noise level and significant cost savings in material, transportation and storage.
Moreover, brazed heat exchangers offer a more constant performance over time compared to traditional round tube heat exchangers, but to ensure reliable operation, the choice of materials and combination of alloys in the system are very important. Because of the size of the heat exchangers, high-strength alloys are specially suited to these applications.
Air-cooled condensers are used in many refrigeration applications, including (but not limited to) food processing plants, supermarkets and restaurants. Brazed aluminium heat exchangers present several major advantages for these applications: They improve energy efficiency, lowering power consumption and reducing the environmental impact of the refrigeration system. The inherent smaller internal volume leads to lower refrigerant charge, which reduces the periodicity of leak inspections and helps them comply with environmental regulations. They lower weight for transportation and mounting, and allow easy maintenance and cleaning that contributes to a reduction of the overall cost.
Brazed aluminium heat exchangers are compatible with most common refrigerants such as R404A, R407C, R134A, R410A and natural refrigerants, and are able to cope with high operating pressures. The choice of materials and combination of alloys in the system are very important, in order to provide corrosion protection and reliable operation. High-strength alloys are specially suited to these applications.
Brazed aluminium heat exchangers have been used in industrial applications for more than 60 years because of their compact design, superior thermal and hydraulic performance and reduced manufacturing and ancillary costs. Because of size, design and operating conditions, heat exchangers for industrial applications are often vacuum brazed, which imposes special requirements on the aluminum alloys to be used.
Typical applications include:
- Cooling of engine, transmission, hydraulic and lubrication oils
- Separation of gases
- Gas liquefaction
- Gas compression and condensation