The heat dissipation of an LED display screen can be calculated by analyzing heat-generating components such as LED lights, electronic circuits, and drive systems, combined with parameters such as input power and electro-optical conversion efficiency. This calculation can be further applied to heat dissipation structure design and engineering installation cooling system design.
I. Calculation Method for Heat Dissipation of an LED Display Screen
1. Condition Setting
Pixel Pitch: P (unit: mm)
Display Area: S (unit: m2)
Display Brightness: L (unit: cd/m2)
Input Power: W (unit: W)
RGB LED Bead Luminous Intensity: IR, IG, IB (unit: cd)
RGB LED Bead Input Power: WR, WG, WB (unit: W)
2. Calculation of RGB Pixel Light Radiation Power
White Balance Light Intensity Ratio: R:G:B ≈ 3:6:1
Single Pixel Luminous Intensity: Where η is the optical system loss (generally taken as 0.9).
RGB Light Intensity Allocation:
3. Calculation of Total Screen Light Radiation Power
Number of Pixels:
Total Light Power:
LED Heat Power: Where ηr, ηg, and ηb are the electro-optical conversion efficiencies of the RGB LED beads.
4. Calculation of Total Screen Heat Power
Method 1: Input Power Method
Total Heat Power ≈ Input Power × (1 - Total Electro-optical Conversion Efficiency)
Method 2: Estimation Method
Based on the literature "Ultra-Low Dropout LED Driver Saves 32.8% Energy in LED Displays":
LED Light Source Heat Generation Percentage: 50%
Driver Heat Generation Percentage: 45%
Controller and Connecting Cable Heat Generation Percentage: 5%
Total Heat Power Formula:
II. Application of Heat Dissipation in Design
1. Heat Dissipation Structure Design
Basis: By calculating heat dissipation, determine the cabinet material, heat sink fin size, and fan power.
Objective: Ensure that the LED bead operating temperature is below the rated value (usually ≤65℃), extending lifespan.
2. Engineering Installation Cooling System Design
Airflow Calculation: If the display screen is installed in a sealed manner, heat dissipation requires air convection. The formula is as follows:
Heat Conduction Exchange Power:
Where S is the steel structure area, tw is the ambient temperature, tn is the internal temperature, and K is the heat transfer coefficient.
Heat Transfer Coefficient K:
ɑ1 and ɑ2 are the surface heat transfer coefficients, δ is the material thickness, and λ is the thermal conductivity.
Air Convection Heat Dissipation:
Cold Air Intake:
Where C is the specific heat capacity of air, ρ is the density, L is the convection flow rate, and tl is the cold air temperature.
Design Example: If the required internal temperature of the display screen tn ≤ 40℃ and the ambient temperature tw = 30℃, the required cold air intake can be calculated using the above formula, allowing for the selection of appropriate fan specifications.
III. Precautions
Actual Operating Condition Adjustment: The above calculations are based on maximum brightness conditions. In actual use, the display screen brightness is usually lower than the maximum value, resulting in a corresponding reduction in heat generation.
Material Selection: The steel structure casing should be made of materials with high thermal conductivity (such as aluminum alloy) to reduce thermal resistance.
Maintenance Recommendations: Regularly clean the heat sink fins and fan to prevent a decrease in heat dissipation efficiency.
