Cooling Degree Days Calculator

Cooling Degree Days Formula:

\[ CDD = \sum \max(0, T_{avg} - T_{base}) \]

Cooling Degree Days (CDD):

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1. What is Cooling Degree Days?

Cooling Degree Days (CDD) is a measurement designed to quantify the demand for energy needed to cool buildings. It is calculated as the sum of positive differences between the average daily temperature and a base temperature (typically 65°F).

2. How Does the Calculator Work?

The calculator uses the Cooling Degree Days formula:

\[ CDD = \sum \max(0, T_{avg} - T_{base}) \]

Where:

\( CDD \) — Cooling Degree Days (degree-days)
\( T_{avg} \) — Average daily temperature (°F)
\( T_{base} \) — Base temperature (°F), typically 65°F

Explanation: The formula accumulates the sum of positive differences between average daily temperature and the base temperature. Only temperatures above the base contribute to cooling degree days.

3. Importance of CDD Calculation

Details: CDD is crucial for energy management, HVAC system design, utility planning, and climate analysis. It helps estimate cooling energy requirements and assess climate change impacts on building energy consumption.

4. Using the Calculator

Tips: Enter average daily temperature in °F and base temperature in °F (default is 65°F). The calculator will compute the cooling degree days for a single day. For multiple days, sum the daily CDD values.

5. Frequently Asked Questions (FAQ)

Q1: What is the typical base temperature for CDD?
A: The standard base temperature is 65°F (18.3°C), as this is the temperature at which buildings typically require neither heating nor cooling.

Q2: How is CDD used in practice?
A: CDD is used by energy companies for demand forecasting, by building managers for energy efficiency analysis, and by researchers for climate studies and energy policy planning.

Q3: What's the difference between CDD and HDD?
A: CDD measures cooling demand (temperatures above base), while HDD (Heating Degree Days) measures heating demand (temperatures below base).

Q4: Can CDD be calculated for different time periods?
A: Yes, CDD can be calculated daily, monthly, seasonally, or annually by summing the daily CDD values over the desired period.

Q5: Are there regional variations in base temperature?
A: While 65°F is standard, some regions may use slightly different base temperatures based on local climate and building characteristics.