Due to its considerable impact on climate, bus air conditioning systems are being pushed take a new and sustainable path. Electric buses relying transcritical CO2 units perceived be eco-friendly future-proof solutions achieving such target. However, in order have highly efficient systems, the charge needs optimized. In this paper energy exergy-based analyses were performed investigate effect of...

The high irreversibility caused by the expansion valve in conventional transcritical CO2 heat pump cycle has been reported as major drawback on overall system performance. To overcome this problem and recover some of energy lost, different isentropic devices such turbine expander two phase ejector have proposed. This study aims to numerically compare performance transcrtical terms first second ...

Use of Dedicated Mechanical Subcoolers gives rise to the need an optimisation process involving gas cooler pressure, activation and setpoint temperature values, subcooling degree subcooler size, with aim further improving energy efficiency while considering costs. In this paper a thermoeconomic analysis is performed on commercial refrigeration plant, at four climate conditions from warm hot, ti...

• Mechanical subcooling increases the COP of CO 2 systems at high outdoor temperature. The gas cooler pressure plants can be reduced with degree. Optimum degree and optimum cooling capacity subcooler are found. Dedicated Subcooling (DMS) is one most investigated effective strategies applied to increase performance commercial refrigeration in transcritical operation. Further benefits obtained by...

The improper defrosting operation would not only cause severe performance deterioration and energy waste but also reduce comfort. dynamic control strategy of electric vehicle heat pumps is more complicated than that other pumps. To find an efficient logic, a transcritical CO 2 pump test bench for vehicles was built. First, the thermodynamic characteristics in process were analyzed, based on whi...

This study focuses on developing and optimizing of a microchannel gas cooler model for evaluating the performance transcritical CO2 mobile air-conditioning system. A simulation is developed with aid MATLAB R2022a. segment-by-segment modeling approach utilized by applying effectiveness-NTU method. State-of-the-art heat transfer pressure drop correlations are used to obtain air refrigerant side c...

A non-standard bifurcation, similar to a transcritical one, in a model of a bioreactor has been detected. This happens in a periodically-forced system with restrictions on the state space. The bioreactor is periodically fed with substrate. In the mathematical model, a periodic orbit approaches (without hitting) the restriction surface as a bifurcation parameter is varied. The way the orbit appr...