Impact of window parameters on the building envelope on the thermal comfort, energy consumption and cost and environment

In this paper, the impact of window parameters (shape, design, sizes, position and orientation) on the building thermal comfort (temperature, relative humidity and discomfort period), energy consumption (lighting loads, heating and cooling loads and total energy consumption) and cost, and environment effect (CO2 emissions) is analysed under hot semi-arid climate conditions. This study considers the effective window design parameters; window to wall area ratio (WWR), position on the wall, and orientation. An experimental setup is used to validate the numerical solution of the mathematical model by Design-Builder software. Results show that window at north has the minimum interior temperature, discomfort hours, cooling load, CO2 emissions, total energy consumption and energy cost, and maximum lighting, relative humidity and heating load and contrarily the window at south. Window characteristics haven’t great effect on the relative humidity. Increasing WWR increases the cooling load, interior temperature, energy consumption and cost and decreases lighting and heating loads. Window shape ratio (2-1) and middle position represent the lowest in the energy consumption contrarily ratio (1-3) and down position. Controlling, studied window parameters reduces annual cooling load by about 30%, lighting power, CO2 emissions, annual energy consumption and energy cost by about 39%, 22%, 24% and 21%, respectively.