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In this work, the cascaded supercritical CO 2 system integrated with solar and biomass energy is proposed. The system contains two parts, i.e. the recompression cycle and the simple cycle. The solar receiver or biomass burner replaces the combustor chamber in conventional Brayton cycle. Energy analysis and exergy analysis are implemented to evaluate the feasibility of the proposed system. Under the consideration of the changes of solar irradiations and biomass complementary, the design and off-design thermodynamic performances of the system are numerically studied. Results indicate that the thermal efficiency of total system reaches 40.1%. Owing to the introduction of biomass input in the proposed system, the power generation efficiency is insensitive to solar radiations and times, and thus an efficient and stable utilization approach of solar energy and biomass is achieved at all work conditions. The theoretical results indicate that the cascaded supercritical CO 2 with multi-energies input as a power cycle is a promising option for the efficient utilization of the abundant solar and biomass resources in the Western China. [ABSTRACT FROM AUTHOR]

Cooling dehumidification driven by power is widely used in industrial process to obtain dry air, however, the main drawback is the large power consumption. At the same time, large amount of low-temperature waste heat is released to environment directly. There is a great energy saving potential to recover low-temperature waste heat and generate dry air. A novel two-stage liquid desiccant dehumidification system with cascade utilization of a low-temperature heat is proposed. The waste heat is used in a cascade way. The higher temperature heat is used to generate strong desiccant solution, which will be used in first stage dehumidifier. The lower temperature heat is used to drive a single-effect absorption refrigerator and provide cooling energy to the second stage dehumidifier. Simulation results showed that the proposed system can save 96.17% electricity consumption, compared with the conventional cooling dehumidification system driven by power. The ratio of saving electricity and absorbed heat can reach 6.67%. Furthermore, the advantage of cascade utilizing low-temperature heat was elucidated by studying the driven force in the dehumidifiers. This study may provide a new way to perform dehumidification by efficiently using a low-temperature waste heat. [ABSTRACT FROM AUTHOR]

This paper originally depicts a prototype of 300KW th solar parabolic-trough collector having rotatable axis tracking. This prototype has two operation patterns with the rotatable and north-south axis tracking. The tests on the thermal performance are conducted in summer and autumn. The experimental results point out that the measured daily average solar collector efficiency achieves about 38.5% in autumn, with about 7.2 percentage points higher than that of conventional north-south axis tracking. Furthermore, we compare the performance of the prototype between in summer and autumn, leading to a feasible strategy for the improvement of annually average efficiency of solar collector. This study can provide a new approach for the improvement of average solar collector efficiency, bringing about cost-effective solar energy use. [ABSTRACT FROM AUTHOR]

Abstract: Reducing the energy and cost penalties is the critical problem of CO2 abatement. In this paper, through analyzing the effect of system integrating charact eristic of polygeneration system on system thermo -economic performance, the interaction between economic performance and thermodynamic performance is disclosed. And based on the analysis of the components of CO2 avoidance cost, the essence of lower cost penalty for CO2 avoidance in the polygeneration system is revealed. Through sys tem integration, the polygeneration system ca realize the n energy couple between the chemical island and power island, and simultaneously realize the trade-off between the insta lled capital cost and the primary energy saving, which result in very low cost p enalty for CO2 avoidance, 2.7 $/t - CO2, in which the reduction of energy penalty for CO2 avoidance plays the critical role. Furthermore, through analyzing the sensitivity of the cost of CO2 avoidance to the capital cost and fuel cost in the polygeneration system, the results show that it is more sensitive to the capital cost, and then reducing the manufacture cost of equipment is an efficient way to reduce the cost penalty of CO2 avoidance. [Copyright &y& Elsevier]