Wednesday 25 June 2014

WikiEnergy Data Set Statistics

I recently wrote a post about the WikiEnergy data set released by Pecan Street Inc, and have since written a downloader and converter for the data set as part of NILMTK. In total, the data set contains 71 feed feeds monitored across 239 buildings over the period 1 Jan 2014 - 31 May 2014. However, only a subset of feeds were monitored for each building, and many buildings were not monitored for the full 5 months. This post provides a bit more insight into the content of the data set at the time of writing.

Feeds per building:

The histogram below shows the number of feeds monitored in each of the 239 buildings. It can be seen that the mode of the distribution is around 12 feeds per building, and therefore most of these buildings will be useful for evaluation energy disaggregation approaches.

Duration per building:

The histogram below shows the number of months for which each of the 239 buildings were monitored. It can be seen that vast majority of buildings were monitored for the full 5 months, while the remaining buildings were distributed between 1-4 months. However, this distribution will change dramatically once data for 2012-2013 is released.

Percentage energy sub-metered:

The histogram below shows the percentage of energy sub-metered in 235 of the 239 buildings. The remaining 4 buildings appeared to have energy sub-metered greater than 100%, and were therefore excluded from this plot. This distribution has two distinct peaks; one centred around 70% and another which peaks around 5%. The 63 buildings for which less than 40% of the energy was sub-metered are likely to be of limited use for evaluating energy disaggregation methods.

Buildings per feed:

The table below shows the number of buildings in which each of the 71 feeds were present. A description of each of the feeds is available from the Wiki-Energy Knowledge Base. It can be seen that the presence of feeds in buildings is quite sparse. However, the following feeds are present in the majority of buildings: the household aggregate power (use), air conditioning (air1), washing machine (clotheswasher1), dishwasher (dishwasher1), clothes dryer (drye1), electric heating (furnace1) and refrigerator (refrigerator1).

Feed Buildings
use 239
air1 224
air2 38
air3 5
airwindowunit1 3
aquarium1 1
bathroom1 57
bathroom2 7
bedroom1 65
bedroom2 30
bedroom3 4
bedroom4 0
bedroom5 0
car1 62
clotheswasher1 133
clotheswasher_dryg1 28
diningroom1 20
diningroom2 1
dishwasher1 150
disposal1 85
drye1 141
dryg1 29
freezer1 13
furnace1 184
furnace2 29
garage1 25
garage2 3
gen 116
grid 0
heater1 2
housefan1 2
icemaker1 1
jacuzzi1 13
kitchen1 46
kitchen2 17
kitchenapp1 103
kitchenapp2 73
lights_plugs1 79
lights_plugs2 40
lights_plugs3 16
lights_plugs4 4
lights_plugs5 2
lights_plugs6 0
livingroom1 64
livingroom2 10
microwave1 113
office1 31
outsidelights_plugs1 16
outsidelights_plugs2 3
oven1 89
oven2 3
pool1 4
pool2 0
poollight1 2
poolpump1 17
pump1 3
range1 61
refrigerator1 164
refrigerator2 14
security1 7
shed1 3
sprinkler1 9
unknown1 16
unknown2 6
unknown3 1
unknown4 1
utilityroom1 5
venthood1 19
waterheater1 21
waterheater2 2
winecooler1 4

Monday 23 June 2014

Hart, G.W., Prototype Nonintrusive Appliance Load Monitor, 1985

Since Hart founded the field of energy disaggregation back in the '80s, most papers since have cited his 1992 summary article published in the Proceedings of the IEEE. However, I've seen many references to other papers but have rarely managed to get my hands on the full text. For this reason, I was particularly excited when the following technical report surfaced recently:

Hart, G.W., Prototype Nonintrusive Appliance Load Monitor, MIT Energy Laboratory Technical Report, and Electric Power Research Institute Technical Report, September 1985

Apparently, Hart had received a few requests for older papers over the years, which so far he'd been unable to locate. However, he recently came across a copy of the above paper in the online catalog of a library in Singapore. Mario Berg├ęs then requested the paper via an inter-library loan, Suman Giri scanned the paper copy and Simon Leigh (Jack Kelly's MSc student) applied some post-processing to provide you with the beautiful copy you see today. Quite a good community effort in my opinion!

Thursday 12 June 2014

New data sets released by WikiEnergy and University of California, Berkley

I've recently come across two new data sets which have been released in the past month:

WikiEnergy data

Pecan Street Inc have released a large amount of domestic electricity data via the WikiEnergy project. The data set currently contains data from 200 homes, in which both the household aggregate power demand and individual appliance power demands are monitored at 1 minute intervals. The data set currently contains 4 months of data from January-April 2014, although more data is likely to be released soon. The data is freely available to University members of the WikiEnergy community, and full details for database access can be found on the WikiEnergy Knowledge Base after registering.

BERDS - BERkeley EneRgy Disaggregation Data Set

The University of California, Berkley, have released electricity data collected from the Cory Hall on the UC Berkeley campus. The data set contains data collected from 4 categories of sub-metered loads: lighting, HVAC, receptacle (sockets) and other, for which many feeds are available for each load category. The data set contains measurements of active, reactive and apparent power which were collected at 20 second intervals. The data is available for free via Mehdi Maasoumy's website, and a paper briefly describing the data set appeared at the Big Learning workshop at NIPS 2013.

I've updated my blog post of publicly available data sets to include both of these releases.

Sunday 1 June 2014

Attending NILM 2014

I'm really excited to be travelling to Austin tomorrow to attend NILM 2014. I'm particularly looking forward to meeting other people working in the field, so please come and introduce yourself if you're also attending! I've been involved in two papers which will be presented at the workshop:

  1. A Scalable Non-intrusive Load Monitoring System for Fridge-Freezer Energy Efficiency Estimation. Oliver Parson, Mark Weal, Alex Rogers. This paper summarises the final chapter of my thesis, which covers a large scale application of my work to 117 UK households. I'll be presenting this work in the 'new perspectives' afternoon session of the workshop, and also as a poster in the poster session at the end of the workshop.
  2. NILMTK: An Open Source Toolkit for Non-intrusive Load Monitoring. Nipun Batra, Jack Kelly, Oliver Parson, Haimonti Dutta, William Knottenbelt, Alex Rogers, Amarjeet Singh, Mani Srivastava. This paper summarises the initial release of NILMTK; an open source toolkit for energy disaggregation research. This will be presented by Jack Kelly as a 30 minute demo in the final session of the workshop, and also as a poster in the following poster session.

I'll also be attending the Pecan Street WikiEnergy Data conference on the 4th of June, which also promises a very exciting list of speakers.

See you all in Texas!