Overview and outlook of research and innovation in energy systems with carbon dioxide as the working fluid

Abstract

Carbon dioxide (CO 2 , R744) is a natural working fluid with interesting thermophysical properties that have stimulated strong attention by the academic and industrial communities for a broad range of energy applications. The technology readiness level of CO 2 -based energy systems is very diverse due to the increasing consideration that the fluid has been receiving since the 1990s. Hence, the state of the art in CO 2 energy research spans from fundamental thermofluid and chemistry science to commercial system innovations. After a brief compendium on ongoing activities, this paper proposes a roadmap for CO 2 energy research with reference to the cooling, heating and power sectors. The key knowledge gaps and the main challenges at system and component levels are critically discussed. Pathways to advance the understanding and the technological maturity of CO 2 energy systems are also outlined.

A Review of Flow and Heat Transfer Characteristics of Supercritical Carbon Dioxide under Cooling Conditions in Energy and Power Systems

“…Carbon dioxide is a safe, nontoxic, nonflammable, economical, and resource-rich natural working medium widely applied in energy systems. It can be used as a refrigerant for refrigeration systems [2], air conditioners [3], heat pumps [4], and other devices in a trans-critical state [5], as well as an adequate working fluid for systems such as thermal power plants [6], advanced nuclear reactors [7], waste heat recovery [8], and solar thermal power generation [9]. In these systems and cycles, the condensers or coolers undergo a supercritical heat transfer process, which plays an essential role in cycle efficiency.…”

Avaliação teórica e experimental da remoção de dióxido de carbono de ar seco pela técnica de separação supersônica.

“…On the other hand, R1324yf presents a non-ideal behavior that influences the nozzle wall shape construction. CO 2 was studied due to their common use in refrigeration and power cycles (ORC and supercritical Brayton cycle) (Bianchi et al, 2021), and these cycles normally require supersonic expansion for their operation (Zhu et al, 2017;Uusitalo et al, 2019;Quan et al, 2020). Refrigerant R1234yf was analyzed because it has become an important commercial refrigerant in the air conditioning industry.…”