Xiaosong Zhang

Simulation on Long-Wave Radiation Restraining Performance of Honeycomb Structure

A simulation program of different shapes honeycomb was made to analyze its radiation restraining performance based on Monte Carlo method. The long-wave radiation restraining coefficient was defined and calculated. The results derived from two judge conditions were averaged and regarded as final coefficient values. The results showed that increasing aspect ratio could increase the coefficient, but the change speed slowed down with the increasing of it. Glass circular tube with larger wall thickness had a smaller coefficient, while polyester film with larger wall thickness had a larger coefficient. With the same wall thickness, the long-wave restraining coefficient of triangle polyester honeycomb was smaller when aspect ratio was small. But when aspect ratio increased, coefficient of triangle polyester honeycomb would exceed that of square polyester honeycomb due to faster increasing speed. For large aspect ratio, the triangle honeycomb was a better choice than square honeycomb.

Performance of a Solar-Air Source Heat Pump System for Water Heating on Different Weather Conditions

A new type of solar-air source heat pump water heating system was developed for space heating and residential hot water supply. The specially designed multi-source collector/evaporator (C/E) using spiral-finned tubes could absorb heat from both solar radiation and ambient air. A prototype was designed and tested on different weather conditions in October in Nanjing, China. The experimental results showed that the prototype could heat water from 40degC up to 55degC efficiently both in the daytime and at night. It operated in the solar-source mode with a high averaged COP of 5.1 in the daytime when the solar radiation was 731 W/m 2 . Meanwhile, it operated in the air-source mode stably with a averaged COP of 3.5 at night, avoiding using electricity as a backup energy source.

Analysis of a Power Cycle Utilizing Low-Grade Solar Energy

This paper has proposed a power system that can provide efficiently using the heat collected by the collector. The system consists a of the Rankine cycle to recover the collected solar energy. It produces power and provides certain amount of domestic hot water. Based on the models, a calculation was done to analysis the performance of the system at the typical condition. And the results shows that the efficiency is 7.25% with 2 kW work gained.