Thermal Environment Control Of Commercial Kitchen Based On Concave Corner Attachment Ventilation

Generally speaking,commercial kitchen is a complex thermal environment with high temperature,high humidity and severe pollution.The cooking equipment inside commercial kitchen is multifarious and diversiform,and general space occupies rate to be high,general air conditioning gives air mode to be affected easily by the block action of equipment inside the kitchen,reduce thereby give air effect,or occupy indoor necessary space.So it is necessary to explore a new efficient way of air-conditioning and ventilation,to effectively change the business bad thermal environment inside the kitchen,improve personnel’s comfort,and to further reduce energy consumption of air conditioning system operation.In this paper,on the basis of the attached ventilation accumulated by the research group for many years,the author puts forward the concave corner attached ventilation way by making full use of the four concave corners in the room,and studies and analyzes the feasibility of the air supply mode,air distribution characteristics and influencing factors by using numerical simulation method.（1）With a commercial kitchen in Xi’an as the background,established a suitable physical model,verified the model with the existing experimental data,and selected the standardκ-εmodel for numerical calculation.Under the condition of the same air supply,attached with a contrast analysis of the concave corner ventilation and mixing ventilation and thermal pressure ventilation for velocity field,temperature field,CO₂ concentration field,the workspace average velocity and temperature and ventilation effect evaluation,etc.,Found the concave corner attached ventilation is a kind of better than that of mixing ventilation and thermal pressure ventilation efficient ventilation mode,can effectively promote the indoor air flow,the working area temperature is between 25～28℃,and there are obvious temperature and concentration stratification in the vertical direction,which is conducive to the removal of residual heat and pollutant.Within the scope of the study,the feeling is moderate,about 9%,the ventilation efficiency is higher than 1,the PMV value of most measurement points is between（-0.5,0.5）,and the PPD value is within 10%,which ensures good personnel comfort.（2）The characteristics of indoor air distribution under different air outlet layouts（same side,opposite side,four-sided concave corners）and different combinations of ventilation speed and temperature are studied and analyzed from multiple perspectives.The results show that the change of air inlet location and air inlet temperature have less influence on the indoor air distribution,while the number of air inlet and air inlet velocity have greater influence.When supplying air to the opposite side concave corner and the same side concave corner,higher air supply speed and air temperature can bring better comfort to indoor personnel.For four-side concave corner air supply,the indoor ventilation and drainage efficiency is significant,but it is difficult to meet the personnel comfort.（3）Based on the practical application of the ventilation method with concave corner attachment,the influence of factors such as the size,shape,height of the exhaust hood and the amount of smoke exhausted on the indoor air distribution was studied.Studies have shown that the size of the air outlet and the exhaust volume of the fume hood have a greater impact on the indoor airflow organization.The larger the air outlet radius,the more uniform the indoor speed field,the better the air supply availability and comfort;The average speed and temperature in the work area have increased,and the evaluation index of the ventilation effect has changed little.The shape of the air outlet and the height of the exhaust hood have little effect on the indoor air distribution.Therefore,in the design,comprehensive consideration should be given to the requirements of energy saving and comfort,and the appropriate size of the air outlet and the exhaust volume of the fume hood should be selected.