Advanced Materials Research Vols. 374-377

Abstract: Abstract: Active barrier system (ABS) capping zeolite with large surface area and strong adsorption ability is an effective way to control eutrophication of lake since it can remove ammonia in the lake released by sediment. Influence of the initial nitrogen concentration on eliminating nitrogen load of europhia sediment capping with active barrier system (ABS) were studied through an investigation of the repairment results of serious pollution period (total nitrogen concentration up to 25.33 mg/L), moderate pollution period (14.39 mg/L) and the slight pollution period (3.47 mg/L) of the ancient Canal of Yangzhou. The results showed that: (1) zeolite F1 inhibition effect is stronger than zeolite F2. More TN were removed as the initial TN concentration increased and longer rapid inhibit period were presented with the increased initial TN concentration. (2) The ammonia nitrogen in sediment could be rapidly released into the overlying water, and with lower initial TN concentration in source water, more ammonia would be released from the sediment. Long time treatment was necessary to inhibit the release of ammonia completely if the water showed a high initial TN concentration. (3) After covering zeolite, the total nitrogen in the overlying water were removed mainly through nitrification and denitrification. At the initial TN concentration of 3.47 mg/L, 14.39 mg/L, 25.88 mg/L, 61%, 45% and 52% of TN were removed by the conversion of ammonia to nitrogen gas, however, others left in water as nitrate nitrogen and nitrite residues, and 90% was nitrate nitrogen.

Abstract: Through the experiment on a special designed packed bed, the performances of dehumidification on this packed bed are present in this paper. By testing 3 positions inside the bed, the results are following. During the regeneration process, the average desorption rate of the tail position in this bed is 10.6 g/kg per second, which is respectively 1.93 times that of the fore position and 2.23 times that of the middle position. And for the inlet air of 23 oC, 90% and 1500m3/h, in the stable adsorption process, the adsorbent dehumidification rate of the tail position is 9.51 g/kg per second, which is respectively 2.87 times that of the fore position and 3.51 times that of the middle position. The tail position of the bed holds the best performance both in the regeneration and the adsorption.

Abstract: Temperature field in thermoelectric arm and refrigeration output equation of a thermoelectric cooler was investigated by theoretical and experimental methods. Temperature differences between hot side and cold side were measured. Experimental data were used to prove the peak of the temperature parabola is located at hot side. The terms in refrigeration output equation can’t be explained as heat conducted from hot side to cold side and half of Joule heat respectively.

Abstract: There is some restrictive in reducing office building energy consumption by natural ventilation and mechanical ventilation. Mianyang city is a typical city in northwest Sichuan P.R. According to the typical weather condition and building spatial arrangement, natural ventilation and mechanical ventilation can be used to save energy by efficiency ventilation management.

Abstract: With the development of urbanization, the building energy conservation has been paid more and more attention, and 50% to 60% of the power energy consumption—the energy consumption of air-conditioning be paid attention for people. Research about measuring and analysis on energy consumption of VAV air-conditioning system is described in this paper. A measuring and analysis solution has been implemented in the VAV Air-Conditioning laboratory of Xi’an University of Architecture & Technology (XAUAT). The satisfactory results are given.

Abstract: Experiment research on the air flow rate measurement using tracer gas method in a 300mm internal diameter and 90° elbow duct are presented, which CO and air are selected as tracer gas and gas stream. Results show that the relative errors between the flow rate measured by tracer gas method and turbine flowmeter are varied in the range of -2.15%~1.69% when the injection point is upstream of the elbow on 7D~13D (D is the internal diameter of the duct), and the sampling point is downstream of the elbow on 10D~14D. The further distances of the injection point and sampling point are apart, the less relative errors of the gas flow rate measured by tracer gas method and turbine flowmeter are made. The injection flow rate of tracer gas should be matched with the gas flow rate in the duct. It is a simple and effective method that gas flowmeter online calibration with tracer gas method on the large diameter industrial gas pipeline transportation.

Abstract: To study the performance of the compressor in the HFC125 heat pump system, the volumetric and isentropic efficiencies of a variable speed compressor with pendular pistons were measured with the developed experimental system of HFC125 heat pump in the frequency range of 15-115Hz. The result indicted that there were high volumetric and isentropic efficiencies for the compressor in every frequency. A new model for the calculation of volumetric efficiency and isentropic efficiency were proposed in this paper, and the 146 experimental data of the volumetric and isentropic efficiencies were fitted with the new model. For the volumetric and isentropic efficiencies, the average absolute deviations were 1.749% and 2.815%，respectively, and the maximum deviations were 5.397% and 6.793%, respectively. It could be known that the new model could describe accurately the performance of the variable speed compressor with pendular pistons.

Abstract: By using energy balance method and considering the balance among solar short wave radiation, atmospheric and pavement surface long wave radiations, latent heat fluxes and sensible heat fluxes, a prediction model for AC road surface temperature is established. The pavement temperature and meteorological observation data of Ningbo city (from 2009 July 15 to 2009 August 13) have been used to validation of the model. The results show that a high accuracy was existed between the measured and calculated temperature in the clear days. when S (daily sunshine-ratio)>60%, the maximum absolute error of calculated daily maximum pavement temperature is less than 3 °C, and the multi-day mean absolute error is 1.5 °C. But in cloudy or rainy days, the model’s accuracy will be lower than the clear days.

Abstract: With the aim of evaluating capabilities of a ventilation system with jet fans to control fire smoke in an underground garage, we carried out a set of FDS simulation. According to the results, temperature and soot density of fire has reduced within an acceptable range. We believe that the ventilation system based on the jet fans has indeed controlled fire smoke effectively, thereby we have enough time for safety rescue.

Abstract: A new adjustment law of supply water temperature of heat pump unit was presented by analyzing heat transfer performance and computing supply water temperature of fan coil unit (FCU) in this paper. The paper established the energy equations for air side, water side and FCU in dry and wet conditions, respectively. And the heat transfer performance of FCU was obtained by analyzing the manufacturers’ performance data. According to an actual central air-conditioning system of residential buildings, we calculated the daily inlet water temperature of FCU and proposed the adjustment law for supply water temperature. The results show that the supply water temperature of cooling design day is 9.3°C, the daily supply water temperature of cooling season is higher than 7°C; the supply water temperature of heating design day is 36.4°C, the highest in heating season is 38.5°C, which is below the rated supply water temperature of heat pump unit, 45°C.