Use the exact values you enter in previous answer(s) to make later calculation(s).
Energy-efficient windows are constructed with two panes of glass separated by an air gap (see figure below). In a typical window of this type, the air gap makes a huge difference in the rate of heat flow. The heat-flow rate is much smaller for an energy-efficient window than for a single pane of glass because the thermal conductivity of the air gap is much less than that of a glass pane.
To calculate the rate of heat flow for an energy-efficient window, you will need to use the following information:
1. Thermal Conductivity of Glass Pane: This value represents how easily heat can flow through a material. You can find this value by referring to the specifications provided by the manufacturer or using existing literature on the specific type of glass pane being used.
2. Thickness of Glass Pane: Measure the thickness of the glass pane used in the energy-efficient window. This measurement is usually available in millimeters.
3. Thermal Conductivity of Air: Unlike glass, air has a much lower thermal conductivity. The thermal conductivity of air at room temperature is approximately 0.024 W/(m·K).
4. Thickness of Air Gap: Measure the distance between the two panes of glass, which represents the thickness of the air gap. This measurement is usually available in millimeters.
Once you have these values, you can use the following formula to calculate the rate of heat flow for the energy-efficient window:
Rate of Heat Flow = (Thermal Conductivity of Glass Pane / Thickness of Glass Pane) + (Thermal Conductivity of Air / Thickness of Air Gap)
Substituting the exact values you have gathered will enable you to calculate the rate of heat flow for the specific energy-efficient window you are analyzing.