Applied Mechanics and Materials Vols. 672-674

Abstract: The coefficient of performance (COP), the volumetric refrigeration capacity and the pressure ratio of the refrigeration cycle were calculated for a refrigeration-type compressed-air dryer using natural environmentally friendly refrigerants R717, R290 and R610a and compared with those using R22. Study shows that in the working condition of a refrigeration-type compressed-air dryer the COP and volumetric refrigeration capacity using R717 are 5% and 11% higher than those using R22 respectively and COP using R290 is equal to 98% of COP using R22 and the volumetric refrigeration capacity is equal to 85% of that using R22. Although COP using R600a is 2% higher than that using R22, the volumetric refrigeration capacity is much lower than that using other refrigerants above mentioned. R717 and R290 are recommended as appropriate substitute refrigerants for R22 in a refrigeration-type compressed-air dryer.

Abstract: For the operational optimization problem of supply temperature and flow adjustment (known as “quality-quantity” regulation) in district heating system.To meet user needs hot,an operational cost equation of primary network is set up, taking the supply water temperature and the water flux as variables. The optimization objective of this equation is to minimize operational cost.Based on the genetic algorithm,and finally get the optimal water temperature and water flux. Analysis the several regulation of supply water temperature and water flux, finally proposed heating system integrated regulation.

Abstract: Nowadays, the power load has been well increased and the differences between the crest and the valley of the load has become larger and larger. At the same time, the central air conditioning system plays a more important role in modern life and it has the potential to change these differences. In this paper, in view of a building’s central air conditioning system, central air conditioning system’s power load unload model have been built. A method of calculation of the ability of central air conditioning to unload the load which is based on comfort has been proposed. And it uses the enumeration method for solving optimization of the unloading. Via this research, we can figure out how much load can be unloaded to ease the crest and the valley of the load. And how can we minimize the loss of comfort can also be published.

Abstract: Accordance with the high Precision control problem of constant temperature and humidity air-conditioning system of wine storage of large underground cellar and based on the cellar building construction features and the reasonable allocation of ducts and valves., this paper proposes the distributed intelligent temperature and humidity PLC control solution and designs a remote monitoring system and gives the test results. Actual operating results show that the use of distributed PLC control constant temperature and humidity control system with high efficiency, low energy consumption, remote operation of the file, and meet the environmental requirements of various types of wine storage.

Abstract: Accurate prediction of air-conditioning load is the prerequisite of commercial buildings actively participating in the operation of power grid. The strong correlation factors with air-conditioning load were analyzed in commercial building based on the empirical results, and a temperature sensitivity model of air-conditioning load was got. Considering the humidity, air-pressure and other seasonal difference, a correction sensitivity model with temperature and seasons is proposed. Finally the effectiveness of this model is validated by the calculation example of Shanghai Huitai Building.

Abstract: In this paper the technical features of various representative shipping container refrigeration units were reviewed firstly. A new type of shipping container refrigeration unit was developed. The pull-down experiment was carried out in cool mode (setpoint 0°C) and frozen mode (setpoint-18°C) using the test rig for the refrigeration unit. The experiment results shown that the new type of shipping container refrigeration unit had good pull-down performance respectively in cool mode and in frozen mode. Meanwhile, the control accuracy of the temperature of air inside container can reach ±0.3°C successfully.

Abstract: The coefficient of performance (COP), the volumetric refrigeration capacity and the pressure ratio of refrigeration cycle were studied in a refrigeration-type compressed-air dryer using environmentally friendly refrigerants R410A and R407C and compared with those using R22. Study indicates that under the working condition of a refrigeration-type compressed-air dryer, COP using R410A is 3% higher than that using R407C, the volumetric refrigeration capacity using R410A is 50 percentage points higher than that using R407C and the pressure ratio of R410A is 10% less than that of R407C. COP using R410A equals 96% of that using R22 and the volumetric refrigerating capacity equals 147% of that using R22. COP using R407C is equal to 93% of that using R22 and the volumetric refrigerating capacity is equal to 97% of that using R22. R410A is a more appropriate alternative to R22 than R407C in a refrigeration-type compressed-air dryer.

Abstract: China is a country lacking of freshwater. With the water pollution from bad to worse, saving water become a serious matter which needs to be settled at once. In order to ensure the system working safely and the water quality, most power plants enable the circle cooling water to work in the low consistence, need more drainage and complement water which will make large waste of water. The good water quantity means that the water doesn’t make the furring and make cautery to the equipment. So we can improve the concentrated multiples of the cycle cooling water to save the water. Based on the specialty of the water used in the power plants, this subject study how to estimate the stability, doing the instrument and watching the stability degree, providing the scientific basis for disposing the circling water. After lots of experiments, we use the stability index as the estimation and use the pH determination as the alkalinity determination.The instrument uses the date collecting card to collect and use computer to dispose the date and control the instrument. The system inspects the stability of the cycle cooling water real time automatically.

Abstract: In order to study the effect on indoor thermal comfort when capillary network radiation heating is in diffrent locations, and make capillary network apply to civil construction in the best location. According to the Airpak software,we perform a bedroom thermal environment CFD simulation when capillary network is in three different locations, from which,we get the temperature field, the velocity field and the PMV images. Come to a conclusion,when the capillary network laying on the floor, the temperature distribution is most uniform, the human body comfort is best; when laying on the wall, the heat transfer performance is the best, and get a highest temperature;when laying on the ceiling, the temperature gradient in vertical direction is 0.37 °C /m,the temperature of upside is warmer than downside .

Abstract: A calculation method for cooling load of stratified air conditioning system based on the simultaneously solving model is presented. Thermal environment experiment under summer condition is carried out in a large space building, indoor air temperature, inner wall surface temperature and cooling capacity were obtained; the stratified air conditioning cooling load calculated by the simultaneously solving model is compared with air conditioning cooling capacity in experiment, the relative error is 14%, taking the loss of cooling capacity and leakage loss, it can be thought that the simultaneously solving model can be used to calculate cooling load of stratified air conditioning system.