Applied Mechanics and Materials Vols. 291-294

Abstract: The application of regenerative combustion technology to industry burners has been a huge success. This paper presents an experimental study on the change of the temperature field and the concentration of NO in the flue gas in an industrial furnace. The result showed that the concentration of NO increased with the rise of temperature. For the reversing time of 20s, 40s, 60s, and 80s, the temperature of each point changed in accordance with similar rules, but the temperature of the former three measuring points did not obviously change. The heat transfer occured mainly in the last two layers of the regenerative cells, and the utilization of all the regenerators was only 40 percent. The heating curve of the sixth measuring points was significantly different from the cooling one. With the increase of the reversing time, the flue gas and the air temperature variation also increased.

Abstract: Geothermal heat exchanger is an important part of the GSHP air-conditioning system and different from other traditional air-conditioning systems. This article through to the geothermal heat exchanger heat transfer performance analysis and the design, derived from the geothermal heat exchanger length calculation formula, for actual engineering construction to provide a scientific basis.

Abstract: Analyses the mechanisms of dynamic heat transfer in the underground works envelope and the simplified calculation method for heat transfer. With the cooperative function of MATLAB, Simulink and COMSOL, simulates the dynamic variation of the heat load, and validates the simulation results by an experiment.

Abstract: The mixed refrigerants R22/R23/R14/R740/R728 and R134a/R23/R14/R740/R728 are used in a five-stage auto-cascade refrigeration system for study in this paper. Through theoretic comparison of high temperature stage refrigerant R22 and R134a and repeated experiments we can get the results that the discharge temperature of the refrigerant R134a can be effectively controlled and a lower refrigeration temperature can be got than the refrigerant R22.

Abstract: A four-stage auto-cascade refrigeration cycle is presented in this paper, the kind of mixed refrigerants is chosen and the proportion is simulated by using the commercial software NIST8.0 software. The optimized proportion of mixed refrigerants is gained through experiment, a method which combining software simulation and experiment to define mixed refrigerants proportion is preliminary got by this article.

Abstract: Under dynamic conditions the impact of indoor wind speed, temperature, humidity on thermal comfort are analyzed,and the dynamic thermal comfort research focuses on changes in wind speed and frequency.Through field testing and calculation,the indicators of PMV and PD are compared under dynamic conditions in the evaluation of thermal comfort and applicability.It is considered that PD is more suitable for evaluation of dynamic thermal comfort.

Abstract: Heating of a novel field shower equipment was computational simulated by CFD software in the schematic design phase, and the correction of simulation was verified in the environment laboratory. The results show that, the simulated temperature rise faster than the tested one. It took about 2 minutes earlier to arrive 25 °C, which is the design heating temperature for the shower equipment in cold environment. Since the simplification and assumption was used in the computational simulation, the simulation can reflect the objective situation.

Abstract: This study presents thermal models of pipes or ventilation ducts with variable flow rates. The models are based on dynamic thermodynamic heat balances, and much attention has been put into developing accurate heat transfer coefficients. MATLAB/Simulink environment has been used for modeling, but the model is however universal and can be implemented into any software. The model has been validated against measurement data, and found to be quite accurate for use in typical HVAC applications. Accuracy is particularly good if taking thermal damping into account. Thermal damping of pipe or duct mass has shown to be significant for dynamic performance. The model is suited for control simulations or accurate heat loss simulations, where dynamic conditions are important.

Abstract: Based on technical and economic analysis,apply optimal theory to explore the optimal values of economic specific frictional resistance and put form and a sound theory formula .Apply the formula to the real project and calculate the values of the economic is specific frictional resistance optional pipe diameter and velocity on different heating-supply scale under current prices.

Abstract: This study is focused towards assessing the potential for energy savings and cost reduction by integrating multiple in-house heat stations in several buildings into one larger energy flexible heat system. All existing boilers in stand-alone systems are kept as production units of a new merged system, and will be in addressed and operated when the condition demands it. In this study, energy and cost calculations are done on an hourly basis. Which combinations of boilers to be used in each time step are determined from the lowest running cost for each time step. The results of the case study show a clear savings potential for both energy and costs.