HIGH EFFICIENT INTEGRATED CO_2 REFRIGERATION SYSTEMS WITH EJECTORS AND PIVOTING COMPRESSOR ARRANGEMENTS

摘要

Equipment manufacturers of refrigeration units are facing challenges related to the legislativernrequirements forcing them to implement less conventional refrigerants with lower Global WarmingrnPotential (GWP). The newly introduced next generation of hydrofluorocarbons (HFCs) with ultra-lowrnGWPs do have a very short (atmospheric) lifetime, however, the decomposing products are highly toxicrnin combination with water, short life HFCs and their blends do not represent a safe and sustainablernalternative.rnCO2, a natural working fluid applied since the early days of refrigeration, has demonstrated to be anrnenergy efficient and environmentally benign alternative. Design effort has to be made to developrnaffordable high efficient integrated refrigeration systems applicable in high ambient temperature areas.rnOne way to reduce size and costs is to adapt the number of compressors at the various suction groups.rnAnother enhancement possibility is the utilisation of the normally unused expansion work by applyingrnejectors.rnThe article will describe how enhancement measures like ejectors and pivoting compressors willrninfluences the energy efficiency and can help to downsize systems. Cold energy storage is also anrninteresting feature, supporting the refrigeration systems with accumulated cooling capacity, applicablernduring peak capacity periods, without additional compressors.