The Influence of Air Inlet on Ventilation Effect in Indoor SubstationTransformer Rooms

Ventilation design is the difficulty of transformer room design. Temperature field and velocity field in a transformer room was simulated by CFD method . By comparing simulation value with the experimental value in related document , the effectiveness of the mathematical model was verified. Based on it, an indoor substation transformer built was taken as the simulation object, then designed and simulated six kinds of ventilation condition by changing the location and area of air inlet, focused on the influence of air inlet on the ventilation effect by comparing the temperature field ,velocity field and temperature characteristic value in different condition. The simulation results show that when air inlet area is fixed, the air inlet should be arranged in the radiator side and its center height should be controlled in the radiator center height or slightly offset position, it should not be higher than the radiator. When the air inlet location is fixed, air inlet area should be increased along the high direction to improve ventilation effect. The conclusions can provide technical support for the ventilation design of transformer room.     

Ventilation regulating methods adapting by climate for residential housing

To study the climatic control strategies of the residential building indoor acceptable thermal environment, firstly, based on adaptive model, integrated indoor activities, clothes and spot investigation on air velocity of residential building, this paper calculates an acceptable temperature range. Secondly, through state-space techniques, common passive regulating technologies in residential building have been simulated, including different ventilation rates and divided-period setting ventilation effect on indoor temperature. Meanwhile, monthly regulating methods for ventilation have been proposed. Thirdly, through ventilation technology, effective regulating zone of outdoor climate parameters have been analyzed, which is combined with hythergraph of outdoor temperature, humidity, solar radiation and air velocity. Taking the characteristics of the human thermal comfort adaptability into consideration, the energy-saving potential of the study results is also analyzed.     

大气沉降对水稻各器官铅镉汞砷积累的影响

为了解大气沉降对水稻中重金属积累的可能影响,选择非污染和污染2种土壤,分别在工业区和农村等2种大气环境下开展露天种植与大棚种植对水稻各器官重金属积累的影响试验。结果表明,水稻中积累的重金属主要来自土壤,其各器官中铅、镉、汞和砷的积累量在污染土壤中明显高于非污染土壤;但试验区大气环境与种植条件对水稻茎叶和谷壳中重金属含量也有较大的影响,工业区生长的水稻茎叶和谷壳中重金属含量高于农村,露天种植的水稻茎叶和谷壳重金属含量高于大棚种植。工业区与农村之间、露天种植与大棚种植之间水稻根系和糙米中重金属含量差异不明显,说明大气污染对糙米中重金属的积累无显著的作用。     

AIR DISTRIBUTION IN UNDERGROUND WATER POWERHOUSES

The volume of supply air of an underground water powerhouse is very large. Three methods of air distribution that do not occupy a lot of useful space, these methods are studied by scale model tests in this paper. The results of the tests show that the thermal environment quality at the far end away from the gate is poor if air is supplied from the gate. The velocity may be too high at some points in occupied zone if air is supplied from an end wall. This problem can be solved by reducing the supply air velocity or using an auxiliary slot. The effect of supplying air from the ceiling is satisfactory. The arrangement of one inlet under the ceiling for each generator's zone is recommended.     

Analysis on Summer Thermal Environment Characteristic of a TeachingBuilding Cluster and Validation of Its Calculation Model

A 33-hour field test of outdoor thermal environment was carried out in a typical teaching building cluster located in the hot and humid zone in summer. From the experiment results of local climate data, air temperature, humidity, wind velocity and wet bulb globe temperature (WBGT) at the pedestrian-level, and the typical ground surface temperature, the main characteristics of summer outdoor thermal environment of teaching building cluster in hot and humid zone are obtained. The results show that the patio, overhead and porous pavement can reduce the pedestrian air temperature and WBGT effectively at summer daytime. And the function of the following design methods to improve the outdoor thermal comfort at the summer daytime has the order like overhead>patio>porous pavement>imporous pavement>concrete road. The WBGT at all measuring points at nighttime are almost the same. The test results are further used to verify the existing mathematical models of outdoor velocity and WBGT. The results show that the relative errors are within 6%. Then, the calculation values are in good agreement with the experimental values.     

A Theoretical Study on Thermal Dynamics Model and the Dehumidification Capacity of Hybrid Desiccant Cooling System with Condensation Heat Recovery

The structure and energy conservation characteristics of hybrid desiccant cooling system with condensation heat recovery are introduced briefly. Based on the first and second law of thermodynamics, a system thermodynamic model is established and the solution process given in a diagram. The dehumidification capacity is calculated under different exergy efficiency and indoor sensible heat conditions. The calculation results show that the desiccant wheel barely can compensate for the humidity load of outdoor air under with a ventilation rate of providing fresh air once per hour; when the fresh air rate of ventilation is limited to 0.5 times per hour, however, the desiccant wheel possess sufficient capacity under relatively large wheel exergy efficiency and high sensible heat load.     

地铁用间接蒸发冷却器换热性能影响因素

为解决地铁站冷却塔设置难题,提出了一种采用低速电机驱动旋转布水装置的间接蒸发冷却器,在两种布置方式下,对其换热性能进行了单因素实验,并运用正交实验法对较优布置方式下影响换热器换热的因素进行了分析。结果表明：两种布置方式下,喷嘴与蒸发冷却器的间距、两组换热管束间距均存在最佳值,喷嘴双侧旋转布水优于单侧旋转布水;换热器平行气流布置且喷嘴双侧旋转布水为较优布置方式,此时,换热器换热量随喷水量、转速、空气速度、冷却水进口温度的增加以及喷水温度、空气温度的降低而增大,其中,冷却水进口温度对换热器换热影响最为显著,其他因素对其换热的影响从主到次顺序为：喷水量、空气温度、空气速度、喷水温度、转速、冷却水流量。     

A SYSTBM OF SAVING VENTILATION ENERGY POR MULTI_STORIED HEALTNY BUILDINGS

A sving energy system can get natural ventilation in the storied healthy build-ings with air condition or heating. The principal component of this system is an efficient heat ex-changer made of a set of heat pipes. This system can be operated between two sides of one floor slabto change the energy carried both by the hot air flow and the cold air flow, This svstem can make aspossibly keeping indoor air fresh with a little energy air loss only. It is possible for using this systemto cure a sick building into a healthy building. This system can be put dperation between both thepipes of waste air flow and fresh air flow for an integrated air conditional svstem with fresh air.     

Numerical analysis of Natural Ventilation in Built-in Photovoltaic-Trombe Wall

The natural ventilation in a novel built-in photovoltaic-Trombe wall (BiPV-TW) was numerically simulated by CFD method. The effect of solar radiation, channel width and height on the air flow pattern and ventilation rate was analyzed. Results show that the solar radiation, channel width and height influenced the ventilation rate remarkably. As the solar radiation and BiPV-TW height increased,the ventilation rate increased. As the channel width increasing from 0.1 m to 0.4 m, the ventilation rate monotonously increased. However, when the channel width exceeded 0.5 m, the reverse flow was formed in the top zone and the ventilation rate decreased. A maximum air volume flow rate was achieved when the channel width was approximately equal to 0.4 m in a 3 m height model. The channel width was the dominant factor that influenced the flow pattern in the channel. When the channel width was smaller than 0.4 m, the airflow was thermally stratified laminar flow. When the channel width exceeded 0.5 m, thermally stratified flow disappeared due to the reverse flow formed in the top zone and the laminar flow became turbulent.     

Analysis of Fire Smoke Movement with Different Air Velocity at the Stair head to the Hall of a Metro Station

When a fire happens at the subway platform, the downward ventilation at the staircase which connects the hall and platform can prevent smoke spreading into the hall and provides guiding air for evacuation people. To investigate the influence of the ventilation rate on the smoke movement, the air velocity at the staircase was measured under three ventilation modes. Numerical model was established to simulate the real fire scenario. It is shown that the downward air velocity under fire is greater than that without fire, and the traditional design procedure without considering complex factors interaction in real fire scenario should be improved; when fire is near the staircase, smoke easily spills from the smoke screen to the concourse. And smoke concentration of concourse is even higher than that of platform because the hall is under air supply mode; when the fire locates at the public area of the platform, turning on the tunnel fans can increase the downside flow at the staircase. However exceeding high flow can produce disturbance and destroy the smoke stratification, so more area will be filled with smoke. Therefore, reasonable smoke management scheme is as important as smoke exhausting system capability.     

The Impact of Ventilation and Air Filtration in Controlling Indoor Airborne Microbes

We analyze the generation, transmission and living mechanism of indoor airborne microbes and present two commonly used engineering control methods for microbial contamination: ventilation and air filtration. A mathematical calculation model is developed to incorporate the two ways likely having significant impact on microbial contamination control. We also discuss the relationship between different ventilation parameters and microbial concentration, provide some design equations for determination of microbial filtration efficiency, and calculate the efficiency of air filters used in certain buildings. The results show that the natural ventilation is not a good contamination control for airborne microbes when they are a main indoor pollutant; mechanical ventilation should be used in such cases. If the atmospheric airborne microbes cannot be neglected or its indoor concentration is high, incorporating ventilation with air filtration is a good way to control indoor airborne microbial contamination. Enhancement of filter efficiency at various levels used in central air conditioning systems is helpful for improving indoor microbial contamination control condition.     

One Dimensional Steady Model for Natural Ventilation of Solar Chimney

Solar chimney is effective to enhance the natural ventilation by heating the air with solar radiation. Based on the research by other authors, a revised mathematical model is proposed. One dimensional heat conduction model is proposed when the thermal resistance of both the glass cover and heat absorbing wall are taken into account. The mean temperatures of the air and heat absorbing wall, the air mass rate and heat collection efficiency in the solar chimney are calculated with the present model. The results of the present model are compared with the related experimental data and reasonable agreement is validated. It is shown that the present revised model is able to predict the temperatures of the air and wall, the air mass rate and heat collection efficiency more preciously than the original model.     

Investigation on flow and heat transfer characteristics in capillary porous wick based on alkali metal thermal-to-electric converter (AMTEC)

An axial symmetric invariable temperature phase change interface model of capillary porous wick based on alkali metal thermal-to-electric converter (AMTEC) is established to simulate flow and heat transfer characteristics in capillary porous wick and liquid channel by solving the mass and heat transport controlling equations. The effects of the working fluid flow rate, inlet temperature, porous wick thickness, porosity and effective pore diameter on the distributions of pressure, velocity and temperature are analyzed. In addition, the available effective pore size of the porous wick and the measures to improve the performance of the porous wick are given by analyzing the relationship between the maximum available capillary pressure and the loop pressure drop. The results show that the model presented in gives a good agreement with the three dimensional two-phase evaporation model. The flow and heat transfer characteristics of the capillary porous wick with the alkali metal liquid as working fluid are different from that with the traditional working fluid in some ways.     

Influence of Backfill Air Gap on Soil Temperature Recovery in Ground coupled Heat Pumps

Air gap may easily emerge in the progress of backfill in ground heat exchange due to field operation problems. The single U tube three dimensional numerical heat transfer model is set up and there are 3 kinds of backfill air gap assumptions for computational analysis, which are the most common situations in practical projects. Different air gap situations will have considerable effects on soil heat transfer, especially the factor of soil temperature recovery performance, which is investigated in this research, and there is practical project operating data for the comparison confirmation with the theoretical calculation results in inlet and outlet water temperatures. It can be concluded that the backfill air gap will increase the soil average excess temperature in the period of recovery inside the place where the air gap is, and degrade the heat transfer performance of the ground heat exchange.     

东平湖湖滨带不同植被类型下春季土壤CO2通量研究

为了准确揭示湖滨带不同植被类型的土壤呼吸差异,并为湿地生态系统碳收支研究提供基础理论依据,采用LI-8100A开路式土壤碳通量测量系统,测定东平湖湖滨带3种典型植被类型（香蒲、芦苇、人工杨树林）的春季土壤CO2通量特征。结果表明：（1）3种植物群落中,人工杨树林的土壤有机质明显要高于其他2个原生湿地土壤;（2）3种植物群落的土壤CO2释放速率日变化趋势都均为单峰曲线;土壤碳通量速率最高值在12:00-14:00,最低值出现在6:00。以人为扰动过的土壤,即杨树林群落土壤呼吸速率最大,日平均值达到2.26 μmol/(m2?s);（3）土壤CO2释放速率与近地面大气温度的相关性要高于与土壤温度相关性。分析表明,同一气候区相同环境因子对不同植物群落土壤呼吸的影响作用不同,且因其自身具有明显的日变化,从而导致对土壤呼吸的调控作用也具有明显的日变化模式。     

冰蓄冷低温送风空调系统㶲损因素分析

低温送风空调系统引进新型冰蓄冷设备,采用正丁烷作为制冷剂,制冷剂与水直接接触,换热更强烈且稳定。为了研究该系统相应㶲损因素条件下的节能薄弱环节,实现系统性能优化,基于该系统及各表冷器㶲分析模型,分析了热湿比、新风比、送风温差等㶲损因素对系统㶲效率和各表冷器㶲损率的影响。结果表明:当热湿比变化时,处理二次混风的表冷器㶲损率随之呈正比变化,其他表冷器㶲损率及系统㶲效率随之呈反比变化;当新风比变化时,处理新风的两级表冷器㶲损率随之呈正比变化,其他表冷器㶲损率及系统㶲效率随之呈反比变化;当送风温差变化时,处理一次回风的表冷器㶲损率随之呈正比变化,其他表冷器㶲损率及系统㶲效率随之呈反比变化。     

Mathematical Model and Operation Analysis of Semi-submerged Rotary Orifice Sewage Source Heat Pump Intake Machine

To solve the flow instability and adjustment difficulty of filtering dirt-removing device in the sewage source heat pump system, which affect the efficiency of heat exchanger, semi-flooded rotary orifice sewage auto-strainer was generated. According to establishing the mathematical model, the effect is analysed of pollutant concentration and liquid level height of sewage and rotation period of orifice plate to filtered flow rate, filtered load and filtering surface block coefficient. The result shows that: in the certain condition of sewage liquid level height and orifice plate rotation period, the increase of sewage will decrease the filtered flow rate of orifice plate, and increase filtering surface block coefficient; The effect of pollutant concentration change in the sewage to orifice plate filtered flow rate could be adjusted by regulating the sewage liquid level height and orifice plate rotation period, and the moderating effect of orifice plate rotation period is better than that of sewage liquid level height.     

Simulation of Auxiliary Ventilation Performance of Synthetic Solar House

The passive solar house is one of the effective techniques to decrease the energy consumption of buildings. In this paper, the ventilation performance of synthetic solar house with sunshine room has been analyzed, while it is used as auxiliary ventilation in summer. The mean temperature of air in this room is calculated through the model of heat transfer of solar room, and then the auxiliary ventilation quantity is calculated. It is concluded that the capacity of auxiliary ventilation of synthetic solar house can meet the fresh air demand of common residential construction, but if there are more ventilation quantity needed the capacity of auxiliary ventilation of synthetic solar house is insufficient. The simulation calculation provides the necessary theoretical basis for the further theoretical and experimental research on synthetic solar house.     

Analysis of the Ground Adjustment Ability of the Ground Source Heat Pump Systems in Winter

Based on an actual ground source heat pump system in hot summer and cold winter area, the system operation parameters were tested for 6 years under the state of using cooling tower for cooling in summer but the ground heat exchanger and fire pool for heating in winter. A three dimensional (3D) tube group model was established, and the thermal balance analysis and calculation of the ground temperature distribution around the ground heat exchanger were conducted by the numerical calculation. According to the comparison between the test data and the theoretical results, the influencing factors of the ground adjustment ability were obtained.     

A Study Transient on Predictive Calculation Method of on Underground Ventilation Network

The authors developed a computer program of transient predictive calculation method on underground ventilation network. The program approximated a field data set of seasonal cyclic changes of air Temperature and humidity at the inlet to the sine curves, and included sensible heat conduction from rock to air current. The temperature of rock around and airway was calculated by finite difference method. The prediction method can be used to calculate the variation of flow rates, temperatures and humidities of air flow in the airways along underground network.