Evaporative Cooling Retrofit Strategies for Retail Buildings

Author(s): Pistochini, Theresa; Rastegarzadeh, Laleh; Modera, Mark | Abstract: Evaporative pre-cooling of condenser air improves the efficiency of compressor-based cooling, particularly in the hot, dry climate that exists in most of California. When implementing evaporative pre‐cooling technologies, one of the main concerns for end‐users is deposition of minerals contained in the water onto the surfaces of the heat exchanger, condenser coils, or cellulose based media. This project consisted of a laboratory investigation of the performance of two commercially-available non-chemical water treatment systems, as applied to evaporative pre-cooling of condenser air. The major claim of most non‐chemical water treatment technologies regarding the mechanism by which they work is that they precipitate minerals in bulk water and reduce the amount of calcium carbonate scale that forms on heat exchanger surfaces. An experimental method and apparatus was developed to evaluate non‐chemical water treatment products applied to a spray‐evaporative cooling application and to provide results on two specific products. A physical treatment device manufactured by Watts OneFlow extended the life of the heat exchanger under test by 14% over the baseline when installed with a sufficient flow rate through the device. A permanent magnet device manufactured by GMX extended the life of the heat exchanger under test by 28% over the baseline. Execution of the tests and analysis of the results generated additional insight into how future testing can be improved to reduce uncertainty. However, the results obtained to date provide confidence that physical water treatment systems have the potential to reduce scale formation in evaporative cooling systems and should be further investigated.