Share on Facebook Share on Twitter Email
Answers.com

degree-day

 
Dictionary: de·gree-day
Home > Library > Literature & Language > Dictionary
(dĭ-grē'dā')
n.
A unit of measurement equal to a difference of one degree between the mean outdoor temperature on a certain day and a reference temperature, used in estimating the energy needs for heating or cooling a building.


Search unanswered questions...

Enter a question here...
Search: All sources Community Q&A Reference topics

Sci-Tech Encyclopedia: Degree-day
Top
Home > Library > Science > Sci-Tech Encyclopedia

A unit used in estimating energy requirements for building heating and, to a lesser extent, for building cooling. It is applied to all fuels, district heating, and electric heating. Origin of the degree-day was based on studies of residential gas heating systems. These studies indicated that there existed a straight-line relation between gas used and the extent to which the daily mean outside temperature fell below 65°F (18°C).

The number of degree-days to be recorded on any given day is obtained by averaging the daily maximum and minimum out-side temperatures to obtain the daily mean temperature. The daily mean so obtained is subtracted from 65°F and tabulated. Monthly and seasonal totals of degree-days obtained in this way are available from local weather bureaus.

A frequent use of degree-days for a specific building is to determine before fuel storage tanks run dry when fuel oil deliveries should be made. Number of Btu which the heating plant must furnish to a building in a given period of time is \rm Btu\ required\ = heat\ rate\ of\ building\ \times 24 \times degree\hbox{-}days where “Btu required” is the heat supplied by the heating system to maintain the desired inside temperature. “Heat rate of building” is the hourly building heat loss divided by the difference between inside and outside design temperatures. When the estimating procedure is applied to buildings with high levels of internal heat gains, as in a well-lighted office building, then degree-day data on other than a 65°F basis are required. See also Air conditioning; Comfort heating; Psychrometrics.

Geography Dictionary: degree-day
Top
Home > Library > Science > Geographical Dictionary

A measure of the difference between daily mean temperature and a given standard—such as 0°. One degree-day represents each degree (Fahrenheit or centigrade) of difference for one day.

Architecture: degree-day
Top
Home > Library > Home & Garden > Architecture and Construction

A unit used in estimating the fuel consumption for a building; equal to the number of degrees that the mean temperature, for a 24-hour day, is below the “base temperature”; the base temperature is taken as 65°F (18.3°C) in the US and as 60°F (15.6°C) in Great Britain.

Wikipedia: Degree day
Top
Home > Library > Miscellaneous > Wikipedia

A degree day is a measure of heating or cooling. Totalized degree days from an appropriate starting date are used to plan the planting of crops and management of pests. Weekly or monthly degree-day figures may also be used within an energy monitoring and targeting scheme to monitor the heating and cooling costs of climate controlled buildings, while annual figures can be used for estimating future costs.

A degree day is computed as the integral of a function of time that generally varies with temperature. The function is truncated to upper and lower limits that vary by organism, or to limits that are appropriate for climate control. The function can be estimated or measured by one of the following methods, in each case by reference to a chosen base temperature:

  • frequent measurements and continuously integrating the temperature deficit or excess;
  • Treating each day's temperature profile as a sine wave with amplitude equal to the day's temperature variation, measured from max and min, and totalling the daily results;
  • As above, but calculating the daily difference between mean temperature and base temperature;
  • As previous, but with modified formulae on days when the max and min straddle the base temperature.

A zero degree-day in Energy monitoring and targeting is when both heating and cooling consumption is at a minimum, which is useful with power utility companies in predicting seasonal low points in energy demand.

Contents

See also

References

Notes

Bibliography

External links


Stub icon This climatology/meteorology-related article is a stub. You can help Wikipedia by expanding it.

This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)

 
 

 

Copyrights:

Dictionary. The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.  Read more
Sci-Tech Encyclopedia. McGraw-Hill Encyclopedia of Science and Technology. Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved.  Read more
Geography Dictionary. A Dictionary of Geography. Copyright © Susan Mayhew 1992, 1997, 2004. All rights reserved.  Read more
Architecture. McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc. All rights reserved.  Read more
Wikipedia. This article is licensed under the Creative Commons Attribution/Share-Alike License. It uses material from the Wikipedia article "Degree day".  Read more