Applied Mechanics and Materials Vols. 353-356

Abstract: Solar energy is clean and reproducible energy,it has an important advantage when we use solar energy in heating,supplying hot water and drying in residential buildings.Practical experience confirms that appropriate design of these systems can achieve good results to use solar energy if they compared with conventional system.This paper aims to investigate the good use for solar energy in new rural construction of Lanzhou, we integrate traditional passive solar house, solar heating, solar drying into a new classified system ,design the versatile system for lowtemperature radiant floor heating,supplying hot water and crops drying.Meanwhile, control method and handling precautions are improved.Through further analysis on economic efficiency comparison with solar floor heating and conventional heat source with new rural residential integrated energy price method,analysis on energy-saving and environmental benefit.At last we come to the conclusion the system is worth popularizing in new rural construction.

Abstract: Researches on leak detection system of gas network are significant to fault pipelines diagnosis. In the daily operation of city gas pipeline network, pipeline leakage is the most risky failure type. This paper attempts to review and analyze the existing gas network leak detection systems, meanwhile, design a new kind of leak detection system for daily monitoring and leakage detection of gas network. The greatest advantage of this system is to be able to do all kinds of leak experimental research, especially has great reference value for the leak detection task in colleges and universities.

Abstract: Set up the optimized target function by theoretical analysis of peak-shaving heat source optimization settings, determined optimal locations of peak-shaving heat source and capacity matching relation by comparison analysis. Concluded and analyzed optimal locations and heat capacity matching rule of each heat source when multiple heat sources worked jointly. Results and conclusions provide a valuable reference to the formation on combined economic operation pattern in large scale loop network using multiple heat sources.

Abstract: Based on 2006 look-up tables to analysis the effect of pipe diameters on CHF, the correlations are established for horizontal helically coiled tube by introducing equivalent geometrical parameter. According to experimental data, it is found that the correlation is very suitable, and the regularity of horizontal helically coiled tube geometry parameters on CHF tends to be consistent with that of a vertical tube.

Abstract: With the CFD calculation software FLUENT, numerical simulation has been conducted to study the surface flow and heat transfer in inclined wave fin-and-tube heat exchanger, including uniform angle wave fin and inclined increase-angle wave fin. Velocity field, pressure field and the distribution of temperature field on the air side of fin surface were obtained. Heat transfer performance of the two kinds of fin were discussed and the curve of both heat exchange and pressure drop related to the inlet velocity were analyzed. The results indicates that in the same conditions, heat transfer effect is better than uniform angle wave fin. When the inlet velocity is 4 m/s ,the heat transfer of inclined increase-angle wave fin is about 1.1 times higher than that of uniform angle wave fin meanwhile the pressure resistance is as much as around 1.2 times, which provides a theoretical basis on heat transfer enhancement of wave finned tube.

Abstract: Underground coal mine monitoring system adopts single chip microcomputer and bus articulated structure, the communication mode is CAN field bus, with various intelligent sensors, it can automatically monitor various ventilation indicators of underground coal mine. The test results show that the system has realized real-time monitoring of distributed mass nodes ventilation parameters, through accurate monitoring, simple system structure and flexible operation, it fully meets the need of safe production of coal mine.

Abstract: In this paper, a special lighting system that uses seamless prism light guide as main lighting component and application of the system in a high-humidity room is introduced. Experimental results show that the illuminance level and uniformity in the room has been improved greatly by the application of the guide. The average horizontal and vertical illuminance on main working plan created by the seamless light guide system is individually 74.1% and 101.8% higher than that created by the original lighting fixtures. The application of the seamless light guide system also makes the maintaining work become easier and safer.

Abstract: This article on heating and air conditioning system design of an office building in Langfang city, Hebei province. According to the owners of energy saving and environmental protection requirements and the actual situation, owners of ground source heat pump system. The design from the comprehensive analysis of both the initial investment and operating costs, to offer the choice of reference.

Abstract: Based on the simulation experiment system of on-off heating mode in Hebei university of technology ,tests the surface temperature of the radiator under different conditions,fits curves of the surface temperature changes as the time after the valve turns on and off, and compares the actual and theoretical heat emission.This experimental study applies the theoretical foundation of amending the open time ratio reasonably and metering the heat accurately.

Abstract: A novel micro flat plate heat pipe, micro heat pipe array, was used as heat transfer element in Fresnel lenses concentrator solar cell cooling based on its temperature uniformity and the high thermal conductivity. The contrast experiment was carried out in September in Beijing and the cell performance had been studied for difference cooling means, respectively by ordinary fin and "heat pipe and fin". Experimental results show that compared with cooling by the ordinary fin, for "heat pipe and fin" cooling cell the cell temperature is reduced by maximum 8.2% and maintained at about 55°C. The maximum power is 13.21 W, increases by 7.6%. And the photoelectric conversion efficiency improves 6.1%, with maximum efficiency of 24.13%.