Height Of Outlet Research Articles

Evaluation of the cooling performance of a crushed-rock interlayer embankment with longitudinal ventilation ducts in a pan-Arctic permafrost region

In pan-Arctic permafrost regions, longitudinal ventilation ducts are often installed in embankments to cool the underlying permafrost and thereby ensure road stability. However, the current design methods for embankments with longitudinal ventilation ducts (ED) normally simplify the conjugate heat transfer process between the duct wall and air in the duct. In this study, based on the chimney effect and the theory of fluid flow and heat transfer, we propose an improved numerical method for evaluating the cooling performance of the ED. Using this method, we conduct an assessment of the influences of duct configuration on the efficiency of ventilation duct cooling in winter. The results indicate that increasing the diameter of the duct and the height of the duct outlet can effectively improve the radial cooling range of the ventilation duct. However, the cooling performance of the ventilation duct becomes worse when the length of the duct is increased. To address the limited cooling performance of the ED, we design a crushed-rock interlayer embankment installed with longitudinal ventilation ducts (CED). It is found that the CED is more effective at maintaining the long-term thermal stability of the road in a typical pan-Arctic permafrost region when compared to the ED and the crushed-rock interlayer embankment. Furthermore, a cost analysis of the four different embankment designs reveals that the CED is a financially viable option for embankment construction in permafrost regions.

Experimental study on the influence of inlet velocity and fuel/air ratio on outlet temperature profile performance in a turboshaft engine combustor

This paper presents an experimental study on the influence of inlet velocity and fuel/air ratio (FAR) on the outlet temperature profile in a mixed-flow trapped vortex combustor (MTVC) working with RP-3 liquid fuel. This new MTVC is using a single cavity to stabilize flames for turboshaft engine. Temperature profile performances, such as temperature non-uniformity, radial temperature profile, profile factor (RTDF) and pattern factor (OTDF), were examined at atmospheric pressure on a fan-shaped test rig at different inlet velocities and fuel/air ratios. By analyzing the temperature pattern in the cavity, the reason for the characteristic law of the outlet temperature profile is obtained. The results indicate that the MTVC has achieved a satisfactory temperature profile, which can meet the requirements of the turbine. The radial temperature profile at combustor outlet is not a flat straight line, showing a pattern of high temperature in the middle of combustor outlet and low temperature at both ends of combustor outlet. The peak temperature is 0.6 times the height of combustor outlet. The high temperature zone with a constant FAR lean towards the top of the outlet center, and the temperature non-uniformity, OTDF and RTDF increase with increasing velocity. However, the high temperature zone approaches the outlet axis at a constant velocity as FAR changes. The temperature non-uniformity decreases with an increases of FAR. There is an optimal velocity where OTDF and RTDF pass through a minimum value. A decrease or increase in velocity beyond this optimal velocity results in an increase in both OTDF and RTDF. This mainly depends on the fuel distribution, the air jet mixing, the local FAR in cavity, and the location of high-temperature products in combustor outlet.

Indoor thermal and humid stratification and statistical distribution in ice arenas

On-site measurements in four different ice arenas were carried out under multiple working conditions to study the indoor vertical temperature and humidity distributions. It's indicated that air distribution system has a great impact on the vertical profiles and brings about different inflection points. In order to achieve the same moisture level of around 3 g/kg in the occupied ice field, supply air humidity of jet ventilation should be reduced to 0.4 g/kg while that of ground displacement ventilation could be as high as 3.0 g/kg. The vertical profiles under different air distribution systems are simplified by calculating the air parameter discrepancy brought by dehumidification air supply in the present research. The discrepancy profile was characterized by Gaussian function with three shape coefficients. Based on the measured results, the variation of shape coefficients with different influencing factors was investigated. It is demonstrated that the extreme point coefficient can be estimated by the height of the air outlet, while the scaling range coefficient varied linearly with the relative air supply parameters. This study accumulated considerable measured data to comprehensively understand the current situation of temperature and humidity stratification in ice arenas. The proposed statistical variation distribution contributes to the precise environmental control and the efficient design of ice arenas.

Effects of the height of supply outlet of façade-mounted hybrid downdraft evaporative cooler on the indoor air quality of an office building

The hybrid downdraft evaporative cooler (HDEC) conditions a building by cooling with humidification and hence, inappropriate location of its supply outlet on a building facade has a great impact on the indoor air quality (IAQ) which affect the health, concentration, and productivity of the occupants. This paper investigates the effect of the height of the HDEC supply outlet on the IAQ of an office building equipped with the HDEC system in Bayero University Kano. The building model was created using DesignBuilder software while DesignBuilder CFD was employed for the parametric simulation using air change effectiveness (ACE) as the performance criterion. The height of the HDEC supply outlet was varyfrom 0.1m to 2.4m step 0.1m above the floor level. The results show that higher values of ACE in the occupants’ breathing zone were obtained at lower heights of the HDEC supply outlets with the best ACE of 1.1588 obtained at 0.3m. This information could help engineers to optimally position the HDEC supply outlet on the façade of an office building or any other building with similar characteristics.

Numerical investigation on the role of check dams with bottom outlets in debris flow mobility by 2D SPH

Check dams with bottom outlets are widely used in debris flow gullies to minimize the damage caused by debris flows. However, the bottom size is often based on empirical criteria due to the lack of knowledge of the interaction between the debris flow and the check dam with the bottom outlet. In this study, the interaction between a viscous debris flow and check dams with bottom outlets is investigated via flume tests using 2D smoothed particle hydrodynamics. The normalized height of the bottom outlet is varied from 0 to 1, and slope angles from 15 to 35° are considered. Based on the numerical results, the jump height decays with the increasing normalized height of the bottom outlet and this trend can be approximated by a power law function. When the normalized height of the bottom outlet is less than 0.15, the performance is similar to that of a closed check dam. The flow regulation and sediment trapping functions of the check dam may fail when the normalized height of the bottom outlet is greater than 0.6. These results show that the energy breaking, flow regulation, and sediment trapping functions of check dams with bottom outlets operate well when the normalized height of the bottom outlet is in the range 0.15–0.6. Even if model limitations require further efforts to validate the findings of this study, they provide a basis for the rational design of check dams with bottom outlets.

NUMERICAL STUDY OF THE EFFECTS OF EVAPORATIVE COOLER SUPPLY AIR OUTLET HEIGHT ON THERMAL COMFORT

Thermal comfort in a space equipped with a direct evaporative cooler is a function of the height of the cooler's supply air outlet. This article attempts to numerically investigate the impact of hybrid downdraft evaporative cooler (HDEC) supply outlet height on occupant thermal comfort in an office building. DesignBuilder CFD parametric simulations was carried out by varying the height of the HDEC supply outlet from 0.1m to 2.4 m, step 0.1 m above ground level, using Predictive Mean Vote (PMV) as an objective function. The results show that the best PMV of -0.27 was obtained at 0.4m above the floor level.

Exploring the optimal return air height of different air supply modes based on energy consumption analysis and TOPSIS evaluation method

The side return air is considered to be a ventilation form that can effectively remove indoor particulate matter, and relevant scholars have little research on the height of air return outlet for different air supply methods. In this paper, a single-person ward experimental cabin is established, and the focus is to study the effect of different side return air outlet heights on the particle removal effect under three air supply forms. And use CFD simulation to increase the type of return air outlet height, finally use the technique for order of preference by similarity to ideal solution (TOPSIS) method to comprehensively evaluate the pros and cons of 60 working conditions. The results show that the optimal return air height of top air supply and underfloor air supply is 1.2m, and the best working condition of side air supply is 1.6m air supply-0.7m air return of 12ACH. Most of the working conditions of side air supply are better, followed by top air supply, and finally underfloor air supply.

Enhancing the flow field in parallel spiral-flow column photobioreactor to improve CO2 fixation with Spirulina sp.

A parallel spiral-flow column photobioreactor (PSCP) composed of eight spiral-flow columns, and two pipe headers was designed for scale-up cultivation of microalgae to capture CO2. To solve the disturbance of spiral flow fields among parallel columns, computational fluid dynamics (CFD) simulation was used to optimize the main structural parameters, such as the number and the height of microalgae solution outlet (MSO), to improve flow field structure and enhance the cells' light/dark cycle. The horizontal velocity in the direction of optical path and the turbulent kinetic energy (TKE) reached the peak values of 0.214 m/s and 5.28 m2/s2 when MSO number was four and MSO height was 1.05 m. Meanwhile, the disturbance of the spiral flow field among parallel columns are minimum, and microalgae light/dark cycle frequency was 33.3% higher than that of conventional bubble column photobioreactor. Therefore, the biomass yield and CO2 fixation rate of microalgae increased by 81.5% and 100.5%, respectively.

Watershed hydrological modelling in data scarce regions; integrating ecohydrology and regionalization for the southern Caspian Sea basin, Iran

The aim of this study is to evaluate an alternative approach to indicate how hydrological processes behave in a given watershed, and to test whether this approach can replace traditional calibration, particularly under data deficient conditions. Therefore, a regional calibration method (RC) was adapted to characterize “parameter-based hydrologic processes” as a function of watershed ecologic attributes. The methodological process included (1) temporal phase, (2) correlation analysis and (3) spatial phase. The defined methodology was carried out on a 4160 km2 area containing 21 watersheds laying in the southern coastal line of the Caspian Sea, Iran. By implementing the RC, regional models were specified corresponding to each hydrological process defined in the Tank model. Testing the reliability of the transferring process of hydrological parameters was conducted using multi-level accuracy comparison (MAC) benefiting from descriptive statistics, scatter-plots and T-test.Both temporal and spatial phases have shown acceptable outputs backed by their ecologic significance, but as an alternative approach to traditional calibration, the standalone RC still needs development to achieve a more robust basis covering all the parameters of the hydrologic model. According to the post-processor MAC, the transferability of six out of twelve regional models (height of lower outlet at the first tank, intermediate flow, deep-percolation, infiltration, surface flow, height of outlet at the second tank) was accepted with respect to the given tests. As such, our method outperformed the number of transferable parameters by an outstanding regional model predicting the surface flow in comparison with similar studies.Although the RC could not achieve total perfection, nevertheless it could still help users by providing more information about the contribution of ecologic variables in the prediction of the hydrological processes of a certain watershed.

Research on the critical equipment parameter control technology of slim cigarette rod forming

In order to obtain the optimal control of the parameters of the critical equipment for the formation of a slim cigarette rod. In this study, the loose-end rate and weight stability are taken as the measurement indicators. According to the five factors that affect the control parameters of the critical equipment of tobacco forming, the “Uniform Design Method” is used to set up different control parameter combinations. The stepwise function is used to analyze the quadratic polynomial stepwise regression analysis, and the control parameter model is established and verified and optimized. The results show that the negative pressure of the suction chamber is 90Mbar, the proportion coefficient of the needle roller is 78%, the thickness of the block above the cleaver disc (the rail of the suction) is 2.5mm, the gap between the wire pressing wheel and the rail of the cigarette gun is 4.3mm, and the height of the cigarette tongue outlet is 4.3mm. The optimal range of the forming parameters of the cigarette rod can be obtained, which can effectively reduce the loose-end rate of the slim cigarette rod and improve the stability of the cigarette weight.

Visualization study on the effect of ambient wind on smoke layer height in chamber fires under natural smoke exhaust condition

Ambient wind often affects the smoke movement and natural smoke exhaust performance in enclosure fires. In this study, six wind speeds and twelve kinds of vent combinations are designed. 72 groups of experiments are conducted to investigate the coupling effects of vent combination and ambient wind speed during quasi-steady state of natural smoke extraction in chamber fires. Compared to the traditional Particle Image Velocimetry (PIV) method, a novel particle image flow field visualization (PIFFV) technique is proposed, and a smoke recognition algorithm for the determination of smoke layer height is developed based on two-dimensional OTSU method. Experimental results show that using the PIFFV method and the proposed algorithm, smoke layer height can be determined more accurately, in comparison to the N-percentage method. When the height of outlet is higher than that of inlet, the worst smoke control effect is found. When the air inlet is located on the windward side, the effect of natural smoke extraction is better under a reasonable wind speed than that in a windless condition. However, when the height of outlet is lower than that of the windward inlet, the optimal smoke control effect is achieved without ambient wind. In addition, when the inlet is arranged on the sideward side, ambient wind has a limited influence on smoke layer height with a lower outlet. Results of this study can provide references for the design of smoke control and ventilation system in room fires.

Increasing Oxygen Mass Fraction in Blind Headings of a Plateau Metal Mine by Oxygen Supply Duct Design: A CFD Modelling Approach

Hypoxia problem has always been a difficult point in plateau tunneling projects. To solve this problem, a blind heading face in a plateau metal mine in western China was taken as the physical model, and the computational fluid dynamics was used to analyze the oxygen mass fraction distribution and oxygen-increasing effect in 1 m, 3 m, and 5 m roadway sections from the heading face. The optimal ventilation system was first built to obtain the optimum height and length of the airflow ducts. Then different cases with various oxygen supply duct designs were built in 2 scenarios. The results found that different oxygen supply duct design has significant influence on the oxygen distribution in the heading face. Also, each design has different optimal height of oxygen outlet. The oxygen supply effect is best when some small holes are made in the oxygen supply duct to diffuse oxygen to the working surface. The finding of this paper is helpful for effective and economical oxygen supply in roadway excavation of plateau metal mine and tunnel.

Study of flue gas emission and improvement measure in a natural draft dry-cooling tower with flue gas injection under unfavorable working conditions

In this paper, we observed that flue gas from a natural draft dry-cooling tower (NDDCT) with flue gas injection could not be discharged smoothly under unfavorable working conditions (e.g., when the louvers are closed in winter), which may have caused severe corrosion on the inner shell of the cooling tower. In light of this issue, we proposed an improvement measure. On the basis of the computational fluid dynamics (CFD) method, we established a numerical model for NDDCT with flue gas injection to predict the flow field and pollutant diffusion. We simulated flue gas emissions for a NDDCT with flue gas injection under normal and unfavorable working conditions. The results showed that the air mass flow rate and heat rejection of the cooling tower decreased significantly, and the air flow in the cooling tower became disorganized when the louvers were closed under unfavorable working condition. Compared with normal working conditions, the pollutant concentration on the inner shell of the cooling tower increased by 1.5 times under unfavorable working conditions. After increasing the height of flue gas outlet, the pollutant concentration on the inner shell of the cooling tower decreased obviously.

A 1.68 Ma organic isotope record from the Hetao Basin, upper reaches of the Yellow River in northern China: Implications for hydrological and ecological variations

Abstract Quaternary hydrological and ecological variation of the paleolakes, intermittently developed within the Hetao Basin in North China, is not only closely related to the evolution of the Yellow River discharge but also influenced by the East Asian summer monsoon. However, long-term variability history of hydrology and ecology of these lakes, as well as the driving mechanism, is still poorly understood. Here, we reconstructed the hydrological and ecological variation of these paleolakes since the past ~1.68 Ma based on the interpretation of multi-geochemical proxies of the organic matter including TOC and TN concentrations, C/N ratios, and the δ13C and δ15N values. The results show that the lakes in the Hetao Basin are dominated by relative low lake level, deteriorated aquatic plant abundances and low phytoplankton productivity during the intervals ~1.47 to ~1.30 and ~1.17 to ~1.07 Ma, and ~0.68 to ~0.60 Ma, while relative high lake level with flourishing aquatic ecosystem and high aquatic productivity occurred from ~0.47 Ma to the last interglacial. Meanwhile, tectonically-driven relative height of the basin outlet, preventing the Yellow River water outflows the basin to widen the Yellow River channel in the basin, may be the key factor resulting in the significant rising of the water level of the paleolake formed within the Hetao Basin from ~0.47 Ma to the last interglacial.

Optimisation of multisource injection of carbon dioxide into goafs based on orthogonal test and fuzzy comprehensive theory

Carbon dioxide is a common inert gas used for fire prevention and extinguishing fires in underground coalmines. However, the single pipeline used for carbon dioxide injection has the characteristics of a narrow inerting area, serious gas leakage in the field, and poor control. To address these risks, we herein propose a technique for multisource injection of carbon dioxide and for building up an index system of carbon dioxide injection for fire prevention and extinguishing in goafs by analysing the parameters of the gas injection pipe, mining technique, and physical qualities of the inert gas. In addition, a mathematical multi-pipeline and multisource model is built on the basis of the diffusion model of carbon dioxide injection with a single pipeline. To improve the insertion efficiency of carbon dioxide injection, a parameter optimisation method of multisource injection based on an orthogonal test and the fuzzy comprehensive theory is proposed. Using the orthogonal test and the FLUENT numerical simulation method, the relationship of the mining speed at the working face, gas injection position, height of the pipeline outlet, and gas flow are studied. Furthermore, the optimal injection parameters are calculated using fuzzy comprehensive theory. The application of this model at the No.7271 working face in the Yaoqiao Coalmine shows that the optimal injection parameters are calculated with the gas injection volume being 500 m3/h, the gas injection depth being 90 m, and the pipeline number being two. After adopting the optimal parameters of carbon dioxide injection, the concentration of oxygen demonstrates an obvious downward tendency, which is the same as the numerical simulation result. In conclusion, the technique for multisource injection of carbon dioxide can effectively reduce the width of the oxidation zone and prevent spontaneous combustion accidents in goafs.

Local effects on thermal comfort: Experimental investigation of small-area radiant cooling and low-speed draft caused by improperly retrofitted construction joints

Improper attention to construction joints in a building may lead to localized cold spots on the inside surfaces of the building and air leakage through the envelope. This in turn can affect the thermal comfort of residents due to small-area radiant asymmetry and low-speed draft.The effect of these two local discomfort events on thermal comfort were investigated in two sets of experiments. The test setting consisted of a cool-to-neutral environment, in which a custom-built arrangement replicated small-area radiant asymmetry and low-speed draft caused by improper retrofitting of construction joints. Participants rated their thermal sensation and comfort for three consecutive test conditions associated with radiant asymmetry or draft. Each radiant asymmetry condition consisted of a combination of the height and temperature of a small cold spot and the distance between the cold spot and the subject. The draft conditions comprised the height of the draft outlet and the speed and temperature of the airflow. The heights of the cold spot and draft outlet correspond to the feet, chest and head level of a seated person.Draft perception was found to not be linked to the experimental parameters of the draft conditions, and as such was not impacted by improperly retrofitted construction joints. However, several statistically significant relationships were found between the radiant asymmetry parameters and thermal sensation. Nonetheless, these effects were very small, and the variance explained by these parameters was very low. Therefore, small-area radiant asymmetry cannot be used to make practical decisions in retrofitting strategies for construction joints.

Design and Flow Simulation on a Variable Structure Plasma Reaction Chamber

A new variable structure chamber was designed to plasma reaction with two-stage showerhead, and its flow filed dynamic control equation was analyzed and meshed by ICEM. The simulation research for the meshed models was analyzed by a commercial software-Fluent, by changing various parameters such as mass flow inlet, height, diameter and section of outlet. The result shows that the height and diameter variation for chamber has a little influence on the pressure upon susceptor. However, when the mass flow increases in inlet, the pressure improves, and it also changes as the section variation of outlet.

Experimental study on one-side confined jets from a parallel-flow outlet in a push–pull ventilation system

This study conducted a series of experiments on the airflow characteristics of one-side confined jets from a parallel-flow outlet with a two-tier perforated plate and a honeycomb in a push–pull ventilation system. Maximum velocity, maximum temperature and airflow trajectory were analysed and compared with previous studies about different outlets. The results showed that the dimensionless turbulence coefficient of the parallel-flow outlet was smaller than either the cased axial fan with open grille’s or the swirl diffuser’s turbulence coefficients from isothermal condition. Different development laws for the parallel-flow outlet discharging a hot air jet ( Ar0 = 0.024) on the floor were put forward. Furthermore, it was found that the velocity decay rate of the hot air jets with a parallel-flow outlet on the floor was slower than with the circular aperture over a flat surface. When Ar0 ranged from 0.024 to 0.044, a semi-empirical equation was established to describe the trajectory of the hot jets from a parallel-flow outlet in a push–pull ventilation system. In addition, the baffle height of the suction outlet could be determined and corrected appropriately.

영농방법에 따른 논에서의 배출부하량 모의

논은 지역이나 토양, 기후 특성, 오염원 종류, 관개 및 시비 등의 경작방법에 따라 배출 양상이 다양하다. 특히, 시비방법 개선, 효율적인 물관리 등 영농방법 개선을 통한 비점부하 저감이 중요하다. 본 연구에서는 담수논을 대상으로 물꼬높이, 시비량, 관개수 수질에 따른 배출부하량 저감효과를 평가하기 위해, 시험포장의 물수지 및 물질수지 분석자료를 이용하여 CREAMS-PADDY 모형을 보정과 검정을 하고, 영농관리 시나리오를 적용하여 그 결과를 평가하였다. 영농관리 시나리오는 선행연구를 조사하여 배출부하량 저감을 만족하는 동시에 벼의 수확량 저하를 초래하지 않도록 4개의 시나리오로 개발하였고, 대조군은 관행농업을 반영하여 구성하였다. CREAMS-PADDY 모형과 HOMWRS 모형을 연계하고, 과거 기상자료를 이용하여 1981~2010년 영농기의 배출부하량 모의가 가능하도록 모형을 구축하였다. 모형의 보정 및 검정을 위하여 서울대학교 이동저수지 관개논 시험포장에의 물수지 및 물질수지 분석 자료를 이용하였고, 보정 결과 논물 총질소 및 총인의 결정계수는 0.95, 0.84, 모형의 효율지수는 0.95, 0.73으로, 검정 결과 논물 총질소 및 총인의 결정계수는 0.97, 0.85, 모형의 효율지수는 0.91, 0.84로 비교적 높게 나타났다. 영농관리 시나리오 적용 결과 중간낙수 이후 물꼬를 50 mm 증가시켰을 때 배출부하량은 대조군 대비 T-N 1~34%, T-P 5~21% 저감되는 것으로 나타났고, 100 mm 증가시켰을 때 대조군 대비 T-N 5~62%, T-P 8~37% 저감되는 것으로 나타났다. 관행시비량에서 표준시비량으로 시비량을 삭감시 배출부하량은 대조군 대비 T-N 0~16%, T-P 0~9% 저감되는 것으로 나타났으며, 배출부하량 저감양상은 시비직후 강우의 발생유무에 따라 크게 달라지는 것으로 나타났다. 관개수 수질을 호소수 수질환경기준인 4등급을 초과하는 수준으로 관개하는 경우 배출부하량은 대조군 대비 T-N 9~65%, T-P는 9~47% 증가하는 것으로 나타났다. 영양물질의 농도가 높은 관개수가 유입될 경우 논은 수질을 정화하는 경향을 보였다. 시나리오를 종합하면 영농초기의 물꼬높이를 낮게 유지하고, 중간낙수 이후 물꼬를 높게 유지하며, 비료는 강우가 발생하지 않는 시기에 표준시비량으로 시비하고, 호소수 수질환경기준인 4등급을 만족하는 관개수를 이용하였을 경우 논에서의 비점오염 관리에 가장 효과적인 것으로 나타났다. 하지만 고농도의 영양물질이 함유된 관개수를 농업용수로 이용할 경우 수계 전체의 배출부하량에 저감에 있어 효과적인 것으로 나타났다. 본 연구는 현장 실험 이전의 기초 자료로 사용될 수 있을 것으로 사료된다. BACKGROUND: For Non-Point Source(NPS) loads reduction, pollutant loads need to be quantified for major farming methods. The objective of this study was to evaluate impacts of farming methods on NPS pollutant loads from a paddy rice field during the growing season. METHODS AND RESULTS: The height of drainage outlet, amount of fertilizer, irrigation water quality were considered as farming factors for scenarios development. The control was derived from conventional farming methods and four different scenarios were developed based combination of farming factors. A field scale model, CREAMS-PADDY(Chemicals, Runoff, and Erosion from Agricultural Management Systems for PADDY), was used to calculate pollutant nutrient loads. The data collected from an experimental plot located downstream of the Idong reservoir were used for model calibration and validation. The simulation results agreed well with observed values during the calibration and validation periods. The calibrated model was used to evaluate farming scenarios in terms of NPS loads. Pollutant loads for T-N, T-P were reduced by 5~62%, 8~37% with increasing the height of drainage outlet from 100 mm of 100 mm, respectively. When amount of fertilizer was changed from standard to conventional, T-N, T-P pollutant loads were reduced by 0~22%, 0~24%. Irrigation water quality below water criteria IV of reservoir increased T-N of 9~65%, T-P of 9~47% in comparison with conventional. CONCLUSION(S): The results indicated that applying increased the height of drainage after midsummer drainage, standard fertilization level during non-rainy seasons, irrigation water quality below water criteria IV of reservoir were effective farming methods to reduce NPS pollutant loads from paddy in Korea.

Analysis of the Solar Wall Heat Transfer and Energy Saving of Residential Ventilation

It is the considerable measure that adopting the ventilation solar wall to make up the indoor air in winter because this method embodies the effective use of renewable energy. This paper analyzes the needed volume of make-up air in the different conditions of indoor air exhaust in winter and builds a solar wall to heat the make-up air. Under the conditions of different solar wall size of air channel thickness and so on, Conclusions can be simulated by using CFD software. When the optimum cavity width B is 50mm, the height of air supply outlet D is 30mm and the volume of make-up air is 200 m3/h,the maximum temperature rise of the air rises to 24°C.But when the volume of make-up air is 600 m3/h, there has the best energy-saving effect.