Na Deng

Experimental Study of a Low-Temperature Power Generation System in an Organic Rankine Cycle

AbstractThis paper presents a new power generation system under the principle of organic Rankine cycle which can generate power with a low-temperature heat source. A prototype was built to investigate the proposed system. In the prototype, an air screw compressor was converted into an expander and used as the engine of the power generator. The style of the preheater was a shell and tube heat exchanger, which could provide a long path for the working fluid. A flooded heat exchanger with a high heat transfer coefficient was taken as the evaporator. R134a was used as working fluid for the Rankine cycle in the system. This study compared and analyzed the experimental performance of the prototype at different heat source temperatures. The results show that the preheater and flooded evaporator was used for sensible heating and latent heating of the working fluid, respectively, as expected. When the temperature of the heat source increased, the pressure at the inlet of the screw expander increased, and the mass ...

A comprehensive method of surface-line-point energy planning considering low-grade heat: A case study of an eco-agricultural park in Tianjin, China

Buildings account for approximately 50% of the total energy consumption in the world. Efforts have been made to substitute low-grade thermal energy for fossil fuel to achieve thermal comfort in buildings in order to save energy and reduce air pollution. Generally, these efforts are either an incentive policy from the government or the specific technology on how to use one certain low-grade energy. However, the energy planning for a regional architectural complex or how to evaluate the applications of different forms of energy in advance is less published. For this reason, a comprehensive energy planning method for regional architecture complex using low-grade energy, named surface-line-point, is proposed in this article. The important indexes of the energy level gap and exergy price are adopted for surface planning. Exergy analysis can be used to realize the line planning. Hourly load simulation can be used to optimize the operation performance of machine and complete the point planning. The correctness and feasibility of this method is validated through a case study of eco-agricultural park in Tianjin. The surface-line-point planning can be further applied to other building groups to help the engineer select the most appropriate ways of energy supply.

Experimental Research of a New Steam Heat Pump System for Recovering Industrial Waste Heat

AbstractIn accordance with current industrial waste heat and heat requirements, a new steam heat pump system used for recovering industrial waste heat is proposed in this paper which consists of a ...

Simulation analysis and ternary diagram of municipal solid waste pyrolysis and gasification based on the equilibrium model

A self-sustained municipal solid waste (MSW) pyrolysis-gasification process with self-produced syngas as heat source was proposed and an equilibrium model was established to predict the syngas reuse rate considering variable MSW components. Simulation results indicated that for constant moisture (ash) content, with the increase of ash (moisture) content, syngas reuse rate gradually increased, and reached the maximum 100% when ash (moisture) content was 73.9% (60.4%). Novel ternary diagrams with moisture, ash and combustible as axes were proposed to predict the adaptability of the self-sustained process and syngas reuse rate for waste. For wastes of given components, its position in the ternary diagram can be determined and the syngas reuse rate can be obtained, which will provide guidance for system design. Assuming that the MSW was composed of 100% combustible content, ternary diagram shows that there was a minimum limiting value of 43.8% for the syngas reuse rate in the process.