SCHOTT solutions no. 2/2016 > Products and know-how

Refrigerated units also benefit from SCHOTT compressor seals. Photo: Fotolia

Keeping sustainably cool

Environmentally-friendly appliances need even stronger compressor systems, including their all-important compressor terminals. A specialty from SCHOTT provides the right support.

Maren Michel

Air conditioners, vending machines, refrigerators, and electric vehicles: These are just a few of the products now using modern refrigerants like CO2 (carbon dioxide), which are energy-saving and environmentally friendly. CO2 does not contribute to global warming as much as conventional refrigerants such as CFCs (chlorofluorocarbon) and FCs (fluorocarbon). Change, however, brings challenges. In the case of air-conditioners and vending machines, for example, CO2 refrigerants require extremely high pressure to work. That pressure is transferred to the compressor parts, including the seals.
Hermetically-sealed compressors cannot be repaired, so every piece of the compressor, and especially the compressor seals, must be of the highest quality. Photo: Thinkstock
Refrigerators are also switching to environmentally-friendly refrigerants; in addition to the higher level of CO2 pressure, these appliances already have unique demands. Whether a home or retail refrigerator, its doors are opened regularly. A refrigerator compressor seal has to withstand almost regular compressor fluctuations. And with modern Electronic Vehicles (EV) and Hybrid Electric Vehicles (HEV), battery-powered engines demand more power, raising the overall energy demands on a compressor. Besides, EV and HEV compressors must be placed in special locations within the engine, which also leads to further pressure.

Modern sustainability along with power demands means that compressors have to function at extremely high pressures – more than five times higher than classical compressors. In order to work, the ”heart” of the system – the compressor seals – have to be reliable over a product’s lifetime. Ordinary compressor terminals made of polymers are not able to withstand such force and harsh environmental conditions – compressors are often placed outdoors and are exposed to humidity, pressure, vibration and various chemical influences. Instead, a hermetic (airtight) glass-to-metal seal (GTMS) is a stabile solution.
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What are compressor terminals used for?

”Our high-quality compressors are customer-designed and manufactured specifically for each compressor system,” says Shuji Okutani, General Manager for Compressors at SCHOTT Components. Most importantly, SCHOTT designs and manufactures their own glass for GTMS systems. This complete expertise enables what is needed: long-term reliability and outstanding quality for changing products and technologies in a more sustainable world. —