Semi-welded plate heat exchangers (PHEsJ have found use In numerous ammonia systems since the 1980s because of their compactness, efficiency, low ammonia charge, resistance to pressure and temperature cycling, materials compatibility, and ease of modification. Industry has experienced a number of different kinds of non-performing cases involving PHEs and many lessons have been learned by equipment suppliers, contractors, and end users on how to set up systems and how to improve and handle ammonia applications with PHEs. This paper discusses the most important troubleshooting cases and provides suggestions on how to solve them. The paper also discusses challenges and troubles that end users face, and suggests that PHEs may be an option for meeting these challenges. PHEs can achieve greater thermal efficiency with their close temperature approaches. Dry expansion systems may promote the use of ammonia in air conditioning applications because of reduced system refrigerant charge; fusion bonding technology makes contributions in this area. Energy saving and energy recovery require efficient heat exchangers. Ammonia can find increased use for energy saving in absorption chilling and heating and in power production wherever close temperature approach heat exchangers can be used.
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