Passively Maintained Closed Cavity Façade—Experimental Validation of the Mathematical Thermal Model

Abstract

Although glass façades have been on the market for over a century, new improvements, following sustainable standards, are still being invented. An improvement of the actively maintained CCF has occurred in passive maintenance with natural ventilation of the cavity and insulation glass unit placed on the external side, which has served as a true motivation for further research. To develop the idea, a new type of CCF was invented, followed by the creation of the software, whose purpose is to determine optimal CCF façade components. During this research, an experimental and mathematical model was made regarding the thermal behavior, later validated by the measurements on-site in Rugvica, Croatia. Using simplified but unconventional methods, numerous formulae and variables, a simulation of climatic loads onto the CCF was conducted. Validations of the thermal model were made during winter and summer periods for southern and western façade orientation, explaining how heat transfers from the environment to close cavity façade elements. It was found from the analysis that air temperatures of the façade elements follow the outer air temperature, by constant air exchange with the outer space. The results showed great potential with up to 3 °C (5–10%) of difference in experimental and calculated results, thus creating a basis for further improvement of the software with the addition of structural and hygric behavior of the façade element, regarding climate conditions.

Study on the Modified Ventilation Network on the Ventilation Effect and Ozone Migration Characteristics in Grain Pile

“…The ventilation and heat transfer problems can be solved by these Equations [19][20][21] (Equations ( 1) to ( 4)); however, describing the concentration distribution and transport properties of ozone within the grain pile requires solving the ozone component transport equation. The ozone and air mixture flow within the grain pile is assumed to be a laminar flow of an ideal mixture of gases.…”

“…The momentum transfer equation within the grain pile is the following: 4) where µ is the dynamic viscosity of the fluid, in Pa•s; p is the stresses, in Pa; and d p is the equivalent diameter of grain particles, in mm. The ventilation and heat transfer problems can be solved by these Equations [19][20][21] (Equations (1) to (4)); however, describing the concentration distribution and transport properties of ozone within the grain pile requires solving the ozone component transport equation. The ozone and air mixture flow within the grain pile is assumed to be a laminar flow of an ideal mixture of gases.…”