Study On Room Temperature Distributions Of Buildings During Heating Periods

In China,99%of the nearly existing40billion square meters buildings are highenergy consumers. Heating energy consumption per unit area is2~3times that of thesame latitude developed countries. Compared with abroad, heating system is verybackward in our country at present. Heating companies can not keep abreast of theheating temperature of the users, resulting in heating buildings enthusiasm, poorthermal efficiency, which resulting in energy waste.In response to these problems, the heating meteorological parameters around thebuilding and the temperatures distribution in different locations within the officebuilding of the bar shaped and L shaped was measured. The measured results showthat the temperature distribution inside the building is uneven in space and time.Throughout the day, the difference between the lowest temperature and highesttemperature is4.3centigrade in the same position. In the horizontal direction, thevolatility of the temperature distribution in the south side is relatively large, thedifference between the maximum temperature and the minimum temperature is6centigrade, the north temperature distribution is relatively uniform. The temperaturedistribution along the vertical direction is substantially same in different towards,which are the first increase and then decrease along the z-direction and the differencebetween the maximum and the minimum temperature is about4centigrade.Influences of outdoor temperature, room size, location of room, and the personnelactivity level on temperature distribution are investigated. Results show contributionsof the above factors to the non-uniformity of indoor temperature in a building. Theresearches show that: the temperatures inside the building with respect to the ambienttemperatures are in a relatively stable state when the outdoor temperature changes inthe range of10centigrade; the average indoor temperatures mainly affected by thebuilding depth; the fluctuation of temperature distribution is mainly affected by thethe impact of the architecture studio, the activity degree of the hot users and thefrequency and duration of opening the door; the uniformity of the temperaturedistribution is mainly affected by the building height.The three-dimensional heat transfer model of the bar and L shaped building andthe wall heat transfer model was established. The real-time temperature distribution ofthe wall and the heat transfer coefficient was calculated by Matlab according to thethe indoor and outdoor temperature. The mathematical model is established in theFluent software; the virtual solid components of the architecture was defined,including virtual density, virtual specific heat capacity and virtual thermalconductivity; the third boundary conditions was setted; the internal temperaturedistribution was calculated by the implicit iterative method. The maximum difference between the calculated temperature and measured temperature is0.6degrees Celsiusthrough comparative analysis, which verify the accuracy and effectiveness of thebuilding heat transfer model. Dimensionless of the heat transfer model is simplified inorder to find the relationship between the temperature distribution and thedimensionless size，so that the heat transfer model can be used for different shapes ofbuildings. The mathematical model has the advantages of simple, convenience andrapidity.