The number of Cooling Degree Days (CDDs) during a period is an index that is intended to relate to the amount of cooling used during that period. Because cooling is most often used during summer, CDDs are most often calculated over some or all of the summer period, and are designed to reflect how hot that period is. The number of CDDs on one day is defined to be the number of degrees by which the Average Temperature on that day exceeds a threshold, usually taken to be 65F. The number of CDDs over a period is just the sum of the number of CDDs on each day during that period. For instance, a single day of 70F corresponds to 5CDDs. Two days of 70F correpond to 10 CDDs and so on. Days during which the Average Temperature is less than 65F do not contribute any CDDs. This somewhat complicated formula is an attempt to create a linear relationship between a meteorological index and the consumption of power. Contrast with Heating Degree Days (HDDs).
An indicator of space cooling demand. The cooling degree days for a single day equal the average of the highest hourly temperature and the lowest hourly temperature for the day minus 65 degrees Fahrenheit, if greater than or equal to zero.
Cooling Degree Day (CDD) is a form of degree day used to estimate energy requirements for space cooling (e.g., air conditioning, refrigeration). One cooling degree day is obtained for each degree that the daily average temperature is above the base of 65 degrees F. For example, if the daily high temperature is 84 degrees and the daily low is 60 degrees, the average temperature for that day is 72 degrees F. The daily CDD is 7. If the average temperature is less than or equal to 65 degrees, the daily CDD is zero.
a unit used to relate the day's temperature to
A unit, based on temperature difference and time, used in estimating fuel consumption and specifying nominal cooling load of a building in summer.
A cooling degree day is a measure of how much the average of the daily high temperature and low temperature is greater than a reference temperature. In other words how much cooling is required. e.g. Average Temp is 20C, Reference Temp is 18C CDD = 20- 18 = 2CDD. Cooling Degree Days cannot be negative. More details.
Difference between the actual temperature, as determined by the average of the high and low daily temperatures, and 65 degrees F. For example, if the daily high temperature is 77 degrees and the daily low is 65 degrees, the actual temperature for that day would be 71 degrees. The CDD's for that day would be 6 (71-65). If the average temperature is less than or equal to 65 degrees, the CDD's for the day would be zero
CDDs are a way to measure how much cooling is required in some period of time. A large number of CDDs signifies that the building required a large amount of cooling. Zero CDDs signifies that the building did not require any cooling. In case you are interested, CDDs for each day are calculated as follows: CDD = (TMean -TBalance Point ) * Nday+ Where TMean is the average of the high and low temperature for a day, and Nday = 1, and CDD must always be positive. For Utility Bill Analysis, CDDs are calculated separately for each day and then summed together into billing periods.
A quantitative index that reflects demand for energy to cool homes and businesses. A mean daily temperature of 65°F is the base for cooling degree day computations. Cooling degree days are summations of positive differences from the 65°F base. Thus, a day with a temperature of 72°F would count as 7 cooling degree days. Days with the following temperatures, 72, 71, 75, would result in 23 cooling degree days.
A form of degree day used to estimate the required energy for cooling. one cooling degree day occurs for each degree the daily mean temperature is above 65 degrees Fahrenheit.
A cooling degree day is given for each degree that the daily mean temperature departs above the baseline of 75 degrees a given temperature It is used to estimate the energy requirements, and is an indication of fuel consumption for air conditioning or refrigeration. Refer to heating degree day.
A unit measuring the severity of summer or cooling energy conditions. Using a reference temperature of 65° F, degree days are determined by the difference in the mean daily temperature and the reference temperature. For example, a day with 85° F mean temperature has 20 CDD (85-65=20). The annual Cooling Degree Days are the sum of the degree days over a calendar year.
CDD): A measure of how warm a location is over a period of time relative to a base temperature, most commonly specified as 65 degrees Fahrenheit. The measure is computed for each day by subtracting the base temperature (65 degrees) from the average of the day's high and low temperatures, with negative values set equal to zero. Each day's cooling degree–days are summed to create a cooling degree day measure for a specified reference period. Cooling degree days are used in energy analysis as an indicator of air conditioning energy requirements or use.
A cooling degree day is given for each degree that the daily mean temperature departs above the baseline of 75 degrees Fahrenheit. It is used to estimate the energy requirements and is an indication of fuel consumption for air conditioning or refrigeration. Related terms: degree day and heating degree day
useful in determining cooling energy requirements. Defined as (MT - 65)= CDD, where MT is Mean Temperature (F). If MT is less than 65 degrees F, CDD=0. MT= Mean (average) Temperature of the day.