08 Jul
08/07/2020 10:00

Sciences & Société

Soutenance de thèse en visioconférence : Naveed AHMAD

Measurement of Energy Performance: Analysis of QUB method

Doctorant : Naveed AHMAD

Laboratoire INSA : CETHIL

Ecole doctorale :  ED162 : Mécanique, Énergétique, Génie Civil, Acoustique (MEGA)

The quick U-building (QUB) method is used to measure the overall heat loss coefficient of buildings during one to two nights by applying heating power and by measuring the indoor and the outdoor temperatures. In this work numerical QUB experiments are performed with different initial conditions (initial power), boundary conditions (solar radiation) and designs of QUB experiment (heating power and time duration). In order to simulate the QUB experiments a dynamic state space model is developed. The developed model is validated using IEA EBC Annex 58 data for a single story house. The QUB experiments are simulated for this house, using different initial conditions, boundary conditions and different seasons. QUB method shows robustness to variation in the value of the overall heat loss coefficient for which the experiment was designed and in the variation of optimum power for the QUB experiments. The variations in the QUB method results are smaller on cloudy than on sunny days, the error being reduced from about 10
% to about 7 %. A correction is proposed for the solar radiation absorbed by the wall that contributes to the evolution of air temperature during the heating phase. The QUB results with variable outdoor temperature during the test show relatively high variation and error as compared to the conditions when temperature is constant. A ±20% increase or decrease in the outdoor temperature during the QUB experiment can change the results of test by ±5%. The QUB results for 40 experiments simulated during the month of January-December show error within ±15%. The QUB results during the months of June show relatively large variation. The median error of multiple QUB experiments in summers can be reduced by increasing the set point temperature and using two hours of data for the estimation of different variable in QUB equation.

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