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。     

Method and Application of Independent Exergy Evaluation of Temperature and Humidity Control in HVAC Systems

The conception of independent exergy evaluation of temperature and humidity control in HVAC systems is proposed with the corresponding evaluation indexes presented. This type of evaluation process is illustrated in an air conditioning system with primary return air from the view of thermodynamics. The results show that exergy efficiency of sensible heat is larger than that of latent heat. The reason lies in the fact that the destructions in reheat process and condensed water are very serious. It is concluded that the surface air cooler is not an energy saving equipment in respect of exergy utilization, and the regeneration of the supply air stream at the state of dew point would improve its exergy efficiency of latent heat. The analysis indicates that this independent exergy evaluation is benefit for the exergy evaluation for HVAC systems, and it provides effective resolutions.     

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 Simulation of Natural Ventilation and Thermal Environment in Industrial Plant with Heat Source

Numerical simulation of typical industrial plant was conducted by computational fluid dynamics (CFD) method. The influences of distances between fresh air inlet and ground on thermal environment and distribution of pollutant concentration in working zone were discussed when the heat source intensity and pollutant source were fixed. The main features of industrial plant with heat source were analyzed. The air velocity in working zone and the radiation between the wall surfaces should be considered for comprehensive evaluation of the thermal environment of industrial plant. Heat stress index, HSI, was introduced as thermal index to evaluate the thermal environment. Results showed that lifted fresh air inlet was not only helpful to increase the ventilation rate and the air velocity which improve the thermal environment in working zone, but also to decrease the mean pollutant emission concentration in the plant. When the distances between fresh air inlet and ground increased, the ventilation rate and the air velocity in working zone increased and the HIS and pollutant concentration decreased. When the distances between fresh air inlet and ground exceeded 1.2 m, the ventilation rate and the air velocity in working zone tended to be constant.     

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.     

主动式冷梁热工性能仿真模型及实验验证

以无限空间射流理论和表冷器换热理论为基础,对主动式冷梁的工作原理进行了分析。在假设条件下,建立了诱导送风模型和干工况表冷器换热模型。结合这两种模型,最终建立了主动式冷梁工作模型。在设定的5种静压箱静压值下,对主动式冷梁样品的一次风量、二次风量、水侧换热量等热工参数进行测试。选取诱导比和制冷量两个表征冷梁性能的参数作为标准,对模型理论值与样品实际值进行了一致性与差异性分析,验证了所构建的主动式冷梁模型。     

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.     

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.     

The Analysis on the Effect of Cold and Heat Fluid Inlet Temperatures on the Thermodynamic Performance of Heat Exchanger

Based on the exergy analysis method,the thermodynamic performance of high and low temperature heat exchangers is analysed and the calculating expressions of exergy efficiency are given,which can be used to study systematically the effect of cold and heat fluid inlet temperatures on the exergy efficiency of the high and low temperature heat exchangers on the condition of considering pressure exergy loss and not.     

Simulation and verification experiment of thepneumatic brake LSPV based on AMESim

Based on the analysis of dynamics method of pneumatic transmission, the mathematic model of air brake Load Sensing Proportional Valve (LSPV) is established by fluid servo control theory. The air brake LSPV of one All Terrain Vehicle (ATV) is simulated with the platform of advanced modeling ervironment for performing simulations of engineering system(AMESim), then the input and output pressure characteristic curve of the valves are obtained. The characteristic curve shows, with the load increasing, the pressure adjustment point of Load Sensing Proportional Valve (LSPV) moves up. When the pressure reaches into the pressure adjustment point, the increase rate of output pressure is less than the increase rate of input pressure, so that it can effectively prevent the lockup of the rear wheel precede the front wheel. The result of the simulation is consistent with the experiment result. The validity of the model is verified, which provide foundation for the simulation of the air brake elements and brake system.     

Development of a moisture absorber for packaging of fresh mushrooms (Agaricus bisporous)

Polymeric films used in fruit and vegetable packaging have lower water vapour transmission rates relative to the transpiration rates of fresh products. Therefore, high humidity conditions prevail in the packages, causing moisture condensation, microbial growth and decay of the product. A possible solution to control humidity is to use moisture absorbers. However, existing moisture absorbers either have low absorption capacity and/or absorb moisture quickly, making them unsuitable for mushrooms. This study was undertaken in order to develop a moisture absorber with high moisture holding capacity and slower rate of moisture absorption for packaging of fresh mushrooms. Fast absorbing moisture absorbers such as CaCl₂, KCl and sorbitol were mixed with a slow absorbing desiccant such as bentonite in different proportions. The best combination was found to be with bentonite, sorbitol and CaCl₂ in proportions of 0.55, 0.25 and 0.2 g g⁻¹ desiccant, respectively. It showed a moisture holding capacity of 0.9 g water g⁻¹ mixed desiccant that remained in powder form during 120 h of storage at 10 °C. Further study was conducted to evaluate the kinetics of moisture absorption of this mixed desiccant at 4, 10 and 16 °C and at different humidity levels of 76, 86 and 96%. The change in moisture content of the mixed desiccant with respect to storage time was fitted to a Weibull distribution model. The moisture holding capacity was found to be dependent on the relative humidity; it increased from 0.51 to 0.94 g water g⁻¹ desiccant when relative humidity was increased from 76 to 96%. The kinetic parameter of the Weibull distribution function was found to be dependent on both temperature and relative humidity. Overall appearance of mushrooms improved when 5 g of mixed desiccant was packed in 250 g of mushroom punnet compared to those packed without desiccant.     

苏北地区日光温室能量分配动态研究

为了进一步提高日光温室保温性能,减轻温室内低温寡照灾害发生,以苏北（徐州）番茄日光温室为研究对象,利用采集的2010年12月-2011年4月温室小气候数据及番茄发育数据,根据日光温室小气候形成的物理过程与机理,系统研究了冬春季节不同天气类型及不同叶面积指数对温室能量分配的影响。结果表明：日光温室内潜热、显热随着室内总辐射量的改变而发生变化,阴天以显热消耗为主,潜热消耗量全天低于显热;晴天日光温室内用于作物蒸腾的能量显著多于阴天,阴天室内外贯流传热消耗的能量远远多于晴天;随着叶面积指数增大,到达地面的太阳辐射减少,地面升温慢,室内空气与地表的显热交换量减少,同时室内空气与墙体的显热交换增加。本研究结果可为温室的结构优化及冬春季节日光温室管理提供科学依据。     

Analysis on cooling load on hot mine

Air stream of hot mines is taken as research object, and energy balance equation is established. Cooling load expressions under five different conditions are derived through strict theoretical derivation, i.e. unsteady multi-stream, steady flow, steady flow ignoring kinetic energy change, steady flow ignoring potential energy change and steady flow ignoring fan power change. Then the enthalpy variable expression of the subsurface moist air and heat calculating process of surrounding rock are deduced. Finally, Yong Chuan coal mine illustrates and summarizes the process of calculation cooling load quantitatively. It is conducive to scientificly manage hot mine and design mine ventilation.     

Numerical simulation of hydrogen air combustion in meso scale IC engine

The burning rate of hydrogen air pre mixture on meso scale is mainly determined by its chemical reaction rate. So a Laminar Finite Rate Model, the gas phase reaction mechanism for the combustion of hydrogen air mixture which consists of 19 reversible elementary reactions and the dynamic mesh method are adopted to simulate the combustion of hydrogen air mixture in a meso scale IC engine which operates a quasi gas power cycle under ultrahigh combustion load. The combustion of hydrogen air mixture on meso scale in the micro combustion chamber with moving boundary can be stable. The complete thermodynamic process of heat addition, internal energy increasing, and a boundary work output producing during expansion can be perfectly achieved in the closed combustion system of the meso scaled IC engine igniting the hydrogen air mixture by wire surface of high temperature. However, running parameters such as cycle period, initial pressure and fuel/air ratio have complex effects on the hydrogen air combustion of micro closed container with moving boundary.     

Energy efficiency analysis on intermittent operation based on life cycle cost in the vertical ground source heat pump system

Intermittent operation can affect the heat exchange performance of the vertical ground source heat pump system, thereby affecting life cycle cost (LCC) of the ground source heat pump system. The simulation analysis on the hourly load of an office building is implemented by using the DeST software.The heat exchange model of vertical ground heat exchanger pipe-group and energy consumption model of per part of heat pump system are established. Through the comparison between calculation results of continuous operation for 15 years and calculation results of intermittent operation 15 years of the heat pump system, it can be concluded that the LCC value of intermittent operation decreased by 13.45%,relative to the LCC value of continuous operation, and the average energy saving rate of intermittent operation mode is 17.20% in the entire life cycle. Intermittent operation mode can effectively improve energy efficiency of the ground source heat pump system and reduce the LCC value.     

乙二醇蓄冷库的设计和性能

为探讨乙二醇作为蓄冷剂的蓄冷库用于果蔬贮藏保鲜的可行性,研究人员设计了包含制冷循环系统、蓄冷剂循环系统和保鲜库制冷系统三个循环的乙二醇蓄冷库。按照国家标准冷库热工性能试验方法对研制的蓄冷库的围护结构传热系数、冷风机制冷量、耗电量和库内温度波动等冷库性能进行了分析,结果表明,研制的乙二醇蓄冷库,围护结构传热系数为0.20 W/(m2·℃),冷风机制冷量5.4 kW,耗电量35.48 kW·h·d-1,库内温度不均匀性2.8℃,平均温度波动±1.0℃,达到了果蔬贮藏保鲜设施的技术要求。     

安徽省池州市生态经济可持续发展评价

应用生态足迹模型并结合Ulanowicz的发展能力公式,分析了池州市1996—2004年的生态足迹及发展能力的变化,结果表明：池州市人均生态足迹由1996年的1.1906hm2上升到2004年底的1.8433hm2,人均生态承载力由1996年的0.6759hm2减少到2004年的0.6430hm2,生态赤字逐年提高;发展能力由1.3047增加到2.3793;区域生态经济系统的供需结构存在严重的不平衡。表明尽管池州市9年间区域生态经济系统的整体水平在不断增强,但其发展模式一直处在不可持续的状态。而9年间万元GDP的生态足迹总体上呈下降趋势,表明池州市资源的利用效率在不断提高。与此同时,结合池州市生态经济发展现状和资源分布特点,提出相应的对策     

Calculating the Cooling Load of Cars'' Air-Conditioning System

This paper adopts harmonic reaction method to calculate the cooling load of the air conditioning system of the NO.1011A loaded miniature cars in Chongqing Chang'an Automobile Company .The study indicates that harmonic reaction method is more exact than traditional steady method to show the dynamic characteristic of cooling load. The maximum cooling load appears on 2:00 pm, it's 3 098 W. Among the whole cooling load,heat load through windows and heat load through components are the biggest,they occupy 50% of the whole amount. Heat load of air leaks occupies 27.3%,which shows that it is necessary to improve the seal of cars. Chongqing Chang'an Automobile Company develops optimize design for the air condition system with this result, which reaches a perfect climate effect.     

高水分粮机械通风降水试验

采用机械通风技术，在外温高子粮温时，用７．５ｋＷ电机驱动风机强制通风２８ｈ，可使原始水分１６％的稻谷降低２－２．４个水分。与晾晒，烘干相比，可节约费用５－１０倍。最佳通风时间为午夜０时至次日凌晨５时之间。     

Analysis of the Temperature Limit of Dynamic Water Intake of Open loop Surface Water Source Heat Pump Systems

Energy consumption of water intake is one of the key factors for energy saving in the application of the open loop surface water heat pump system. An energy efficiency ratio coupling model for open loop surface water source heat pump systems was established on the basis of the energy consumption model for the water intake and the heat pump units. According to energy saving rate and regulation of energy consumption of water intake, dynamic temperature limits of water intake in different water supply temperature of cooling tower and different pump head were proposed so as to find a calculation method of temperature limits of water intake of open loop surface water heat pumps. Moreover, the energy saving rate of surface water source heat pump systems compared with traditional air conditioning systems under various condition was also calculated.