"Degree-Days Under the Microscope" is a stepping off-point for a blog series specifically about some of the benefits and pitfalls of using Degree-Day Regression Analysis for energy management.
Many of these I first discussed in my Peer Review of an extensive work by Professor Tony Day, Professor of Energy in the Built Environment at London South Bank University
He was kind enough to incorporate some of my thoughts in his work and has subsequently commented further on these (and other issues) under the title: 'Degree-days: theory and application', published by CIBSE (TM41:2006).
However, I think there are some remaining problems and novel benefits available that are self-evident when considered with a little common sense and in the light of emerging technologies.
Introductory
Last month I wrote some simple introductory posts - if you understand Balance Temperature and Degree-Days you may not need to read these except maybe as a refresher..
Weather & energy which shows how the two are not-linearly related - mainly beauuse at some stage you need no heating
Degree-Days explains (In a building context) how Degree-Days represent the effect of weather on the heating load or chilling load during a particular period
Degree-day calculation example
Data Sources (GIGO wastes energy management time)
Processing weather data is not the problem - getting reliable weather data is !
We assume you will arrange reliable smart metering of energy utilities - and we do not even make the argument - it is clear!
Pragmatic Shortcomings of Theory
Ventilation rates
A building with opening hours is quite simply too complex for Degree-Day Analysis to represent faithfully - this does not mean conclusions from degree-day analysis are useless, but they must be handled with kid-gloves!
Even if energy demand was linear to weather it does not imply consumption is linear to demand (that assumes many other things...)
Alternative Approaches
Energy by hour of day and outside air provides an analysis tool that overcomes many of the shortcomings of Degree-Day Analysis (while also supporting more accurate DDA). It helps establish at what temperature to enable heating at different times of day, and can be used to assess plant sizing issues
Useful Techniques
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Advanced Tips and Tricks
( Using Pattern Recognition and Common Sense In Equal Measure )
...
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Thanks for reading!