Study On Air Distribution Characteristic And Parameters Optimization Of Stratum Ventilation For Heating

With the development of the social economy and improvement of the living standards,reducing energy consumption and improving indoor thermal comfort are the goals in the field of architecture.Stratum ventilation shows the excellent potential in reducing the energy consumption and improving the indoor thermal comfort for cooling.In this paper,in order to explore the performance of stratum ventilation for heating,the performance of conventional heating methods were compared with stratum ventilation by experiments.In addition,in order to maximize the efficacy of stratum ventilation,the parameter optimization of stratum ventilation was also carried out.Taking office buildings and residential buildings as examples,this paper compared stratum ventilation with mixing ventilation and radiant floor heating by objective and subjective experiments.The results shown that stratum ventilation can improve the average occupied zone temperature by 1.8 ~oC compared with mixing ventilation.Stratum ventilation can increase ventilation effectiveness by 25.00%and increase the thermal comfort by 10.00%compared with mixing ventilation.In addition,the average velocity of stratum ventilation in the occupied zone is similar to that of mixing ventilation,no draft sensation caused by stratum ventilation because of the short distance between the air inlets and occupants.Stratum ventilation can provide higher indoor air quality than radiant floor heating.Stratum ventilation can reduce the response time of temperature by 30 min and decrease the vertical air temperature difference by 1.4 ~oC compared to radiant floor heating.However,compared with stratum ventilation,the average operate temperature of radiant floor heating in the occupied zone can be enhanced by 1.3 ~oC.Stratum ventilation can shorten the operating temperature difference between radiant floor heating and air conditioning system.The above research shown that,the energy-saving and thermal comfort of stratum ventilation are further improved compared with the conventional heating mode.Therefore,the parameter optimization analysis of stratum ventilation were carried out in this study.Based on the Airpak,univariate analysis was carried out on the influence factors of stratum ventilation with ventilation effectiveness and airflow distribution characteristic index as evaluation indexes respectively.The results showed that energy-saving and thermal comfort were two contradictory objectives.Therefore,the economic-comfort ratio was introduced as the comprehensive evaluation index in this study.This paper was taken the economic-comfort ratio as the optimization goal and considered all year round operation of stratum ventilation.The regression analysis of the supply air temperature,supply air velocity,supply air vane and air outlet position was carried out,which was combined with building energy simulation technology and Marquardt method.The optimal year-round parameters of stratum ventilation of the four air outlet positions in five climate zones,namely severe cold region,cold region,hot summer and cold winter and hot summer and warm winter,were obtained.In this study,the distance width ratio(DWR)was proposed as the influence parameter of stratum ventilation.On the basis of economic-comfort ratio,the optimal year-round DWR of stratum ventilation under four air outlet positions in five climate zones were obtained,which was combined with building energy simulation technology and cubic spline interpolation method.The results of this study revealed that stratum ventilation shows the excellent potential of indoor thermal comfort and energy saving for heating application,and this research can extend the research scope of the performance of stratum ventilation for space heating,and provides an important reference for the parameter design of stratum ventilation.