Single- and two-phase secondary refrigerants have much to contribute to sustainable cooling, says academic
Uttar Pradesh, India, 14 April 2019: Single-phase and two-phase secondary refrigerants have much to contribute to sustainable cooling, said Dr Jahar Sarkar, Associate Professor, Indian Institute of Technology, Varanasi. Explaining in brief about the concept, he said, “Secondary refrigerants are heat-transfer fluids and are used for sub-ambient temperature cooling applications, which involve the transfer of heat from a conditioned space to the evaporator of the refrigeration system.” Elaborating, he said, as the working pressure is high within the refrigeration system, there is a chance that the primary refrigerant may leak with long-route evaporator applications. “To avoid the leakage,” he added, “the secondary refrigeration loop is used for a multiple cabinet cooling application.” The single-phase secondary refrigerant consists of an anti-freeze solution, corrosion inhibitor, and biocides, which generally remains in the liquid phase through the loop, whereas the two-phase secondary refrigerants take advantage of the high latent heat during the phase change process in the loop, turning it from liquid to solid to the gaseous state, he said.
Highlighting the extent to which secondary refrigerants such as single-phase and two-phase fluids are used in India, Sarkar added, “Single-phase fluids, such as water-based brines (aqueous fluid), containing glycols (e.g. ethylene and propylene glycols) or salts (e.g. magnesium and calcium chlorides) are widely used in many industries, including ice plant, food processing plant and in supermarkets.” However, non-aqueous single-phase fluids, he said, are also available in the international market.