Jian Lv

Analysis on the performance of photovoltiac/thermal solar system

The paper proposes an experiment table of the PVT system and analyzes the thermoelectric properties of PVT module and PVT system. According to energy conservation law, mathematical model of the system is established, temperature distribution of module and system can be calculated. And then thermal efficiency, electrical efficiency and overall efficiency is obtained. The results show that solar radiation intensity is the critical factor that affects the performance of the PV/T system.

Investigation on Heat Pipe Application in Central Air-Conditioning Systems

An experimental test has been conducted to determine the effect of heat pipe heat exchangers for pre-cooling and re-heating performance of central air-conditioning systems in Hung Hom Sport Centre. The objectives of this research project are to investigate the energy recovery efficiency from using the heat pipe heat exchangers in air conditioning system. The annual energy saving by using the heat pipe heat exchangers. The effect of energy recovery efficiency is significant.

Microstructure and Properties of Zn-Al Filler Metal Brazing Cu/Al Joint

Microstructure and properties of Zn-xAl alloy were investigated, moreover, the strength and microstructure of the Cu/Al brazed joint had been studied. The results indicate that the massive microstructure is granular and fine when Al content is under 15wt.% in the cast microstructure of Zn-xAl filler metal. Meanwhile, the drawability properties of the filler metal is excellent. Thus, the massive microstructure become dendritic and coarse when Al content exceeds 15wt.%. At the same time, the drawability properties of the filler metal become bad. In the microstructure of the brazed joint, the interface layer exists in the interface between the Cu base metal and the brazed seam. The interface layer is mainly consisted of Cu9Al4 and CuAl IMCs. When Al content is under 15wt.%, the interface layer shape is a visibly serrated edge, so the adhesive strength between the interface layer and the brazed seam is higher and the mechanical property of the brazed joint is excellent. The brazed joint strength of Zn-15Al filler metal get highest. But the interface zone become relatively straight when Al content exceeds 15wt.%. In the meantime, the strength of the brazed joint decreases.

The effect of total solids concentration and temperature on biogas production by anaerobic digestion

ABSTRACT This paper analyzed the effect of total solids (TS) concentration and temperature on biogas production from anaerobic digestion with dairy manure. Batch experiments were carried out for TS concentrations of 6%, 8%, and 10%, respectively, at five different temperatures (31, 34, 37, 40, and 43°C). Results showed that two factors both had significant effect on biogas production. The optimal condition for anaerobic digestion was 8% TS concentration at the temperature of 40°C. Under such condition, the biogas production is much better than the others and the yield peaked higher. Daily biogas production of 8% was more than those test groups which are 6% and 10% under the same temperature. When TS concentration was 8%, the rank of total biogas production of different digestion temperature test was 40 ＞ 37 ＞ 34 ＞ 43 ＞ 31°C, the biogas production of the 31, 34, 37, 40, and 43°C was 0.123, 0.159, 0.171, 0.205, and 0.153 L/g, respectively.

Analysis of Solar Energy-Water Source Heat Pump Hot Water System's Optimization Strategy

Through testing the operation of solar energy-water source heat pump hot water system, analysis of the factors that affect system performance, research engineering optimization strategies for improving systems performance. Given some optimization recommendations for both solar energy system and water source heat pump system. Provide some supports for this new technology which use renewable energy in the future development.

Effect of Al on Zn-Al Filler Metal Wettability on Pure Copper Surface

Zn-Al filler metal wettability tests were performed. With the match of CsF-AlF3 flux, Zn-Al filler metal wettability is poor on pure copper surface. The Cu-Al-Zn intermetallic compound interface layer exits between Zn-Al filler metal and Cu base metal. When Al content is low in Zn-Al filler metal, the filler metal wettability is poor and the filler metal melting point is low. In the wettability test course, the time is long in which Cu base metal interacts with liquid Zn-Al filler metal. And the Cu-Al-Zn intermetallic compound interface layer grows thick between filler metal and base metal. With the increase of Al content in Zn-Al filler metal, the interaction strengthens between Zn-Al filler metal and Cu base metal. In the wettability test course, the time beocome short in which Cu base metal interacts with liquid Zn-Al filler metal. The Cu-Al-Zn intermetallic compound interface layer gets thin between filler metal and base metal. Meanwhile, Zn-Al filler metal wettability improves on pure copper surface. But the improvement is not remarkable. Its wettablility is still poor on pure copper surface.

Influencing Parameters Analysis of Solar Energy Regenerator Performance

The paper studied the effect of running and structural parameters on solar energy regenerator performance, in which pebble was storage material. Comparing simulated values to tested values of outlet air temperature, good agreement was achieved, which proved the model was correct. Taking average regenerative power as target function, the simulated results showed that the larger inlet air temperature, the larger average regenerative power. The smaller void fraction, the larger average regenerative power. The larger cross section velocity, the larger average regenerative power.

The Problems and Corresponding Solutions of the Discharging of Biogas Plants for Crop Straw

A great deal of the available biomass resource of straw is idle in china,convert straw into methane gas not only can produce a kind of natural fuel,the straw waste can also generate a kind of natural organic fertilizer,so,take advantage of the bacteria to break down the straw to form methane gas would be one of the best ways to solve the problem of idle straw resource.The comprehensive utilization of straw methane can improve the rural production、living environment,and increase economic efficiency,is a important foundation to deveolp a circulating type of low carbon of agriculture economic and plays an extraordinary role in the new rural construction.The key problem of the straw methane generalize is the pretreatment technology of the straw ;gas generating velocity and efficiency ;the discharging of the straw waste etc.For the area which accelerate the process of live in the form of concentration of the domestic biogas should be controlled,and the direction should be the construction of big,medium-sized straw biogas pools.

Three-Dimensional Pattern Design of Processing Draft

Three-dimensional pattern design of processing draft