A gradient free optimization-simulationmethod for processesmodelledwith the simulator AspenHYSYS is developed. The tool is based on a Tabu Search (TS) and the Nelder-Mead Downhill Simplex (NMDS) method. The local optima that result from the TS are fine-tuned with NMDS to reduce the required number of simulations. The tool has been applied to find the total refrigerant flow rate, composition and...

In order to improve the coefficient of performance (COP) of a heat pump cycle by using carbon dioxide (CO2), an expander that recovers rotation power from the large pressure difference in the cycle to use the power to partially drive the cycle was developed. In the cycle a two stage rotary expander was adopted because the suction control mechanism is not necessary in it. In the development proc...

In this paper, an experimental work was investigated on nanorefrigerant .Nano Al2O3-PAG oil was used as nano-refrigerant in R134a vapour compression refrigeration system . An experimental setup was designed and fabricated in the lab. The system performance was investigated using energy consumption test and freeze capacity test. The results indicate that Al2O3 nano refrigerant works normally and...

Utilization of solar energy can be found in various domestic and industrial applications. The performance of any solar collector is largely affected by various parameters such as glazing, absorber plate, top covers, and heating pipes. Technology improvements have brought us another method for conversion of solar energy to direct electricity using solar photovoltaic system. Utilization and extra...

The use of carbon dioxide (CO2) as a refrigerant is considered for an increasing number of various applications including low capacity transcritical processes. Due to the fluid properties of CO2, the pressure ratio of the refrigeration process is rather low compared to common refrigeration processes while the pressure difference is high. Furthermore, the volumetric capacity of CO2 is higher tha...

current world conditions require compressors to be both efficient and economical to manufacture. one means of improving efficiency in a rotary vane (or any) compressor is to use the lubricant as a heat transfer agent. A rotary vane refrigerator compressor was modified and instrumented for calorimeter testing so that the performance improvement could be identified. The changes and testing were c...

Solar Energy Applications Laboratory , Colorado State University . Fort Collins , CO 80523 Design of a vapor transport solar water heater using R-123 is optimized to maximize thermal performance and minimize life cycle cost. Optimal systems for one and twostory homes are identified in a parametric study of collector area, condenser heat transfer area, water storage tank volume and circulating r...

In recent years, water (R718) as a kind of natural refrigerant—which is environmentally-friendly, safe and cheap—has been reconsidered by scholars. The systems of using water as the refrigerant, such as water vapor compression refrigeration and heat pump systems run at sub-atmospheric pressure. So, the research on water boiling heat transfer at sub-atmospheric pressure has been an important iss...