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What is Joule?

Joule is a web app that fetches, combines / separates and processes the captured energy data, and then displays the data to the user, within a web browser. It carries out all data processing in-browser which negates the need for specific server software to be installed, and only relies on a standard web server able to serve up the static files needed for the app, and the data JSON files. It is just an example of what can be done with energy data and should hopefully open the way to other visualisation tools.

The JSON files

Data files

#sensorindex.json

Provides an index describing all sensors.

{
  "sensors" : {
    "elec" : [
        {
          "function" : "Power",
          "path" : "meters.cl.cam.ac.uk/elec",
          "sensor" : "S-m36",
          "room" : "GN17",
          "readings" : [
            "S-m257-2011-03.json",
            ...
          ]
        },
        ...
    ]
  }
}

elec[array[object]] contains the objects representing electricity meters

function[string] description of the function performed by the branch monitored by the meter

path[string] path of the folder containing the data files

sensor[string] sensor name

room[string] room name

readings[array[string]] contains the names of the data files

#S-m##-YYYY-MM.json is a typical data file name, containing the meter readings at 1 hour intervals. ## is the meter number, YYYY is the year and MM is the month the readings refer to.

{
  "label" : "257 2011-07-06",
  "room" : "GN17",
  "path" : "meters.cl.cam.ac.uk/elec",
  "phase" : "3",
  "description" : "Power",
  "coverage" : "Gates building",
  "type" : "Auto Meter IC1995",
  "ts" : "2013-09",
  "data" : {
    "start" : 1377993600000,
    "step" : 3600000,
    "readings" : [
      148.366,
      149.25,
      ...
    ]
  }
}

label[string] describes the data file with the meter number and the period

room[string] room name

path[string] path to the folder containing this file

phase[string] phase identifier

description[string] describes the type of data

coverage[string] geographical area covered by the meter

type[string] type of meter

ts[string] period the data refers to

data[object] contains the actual readings

start[int] timestamp at which the readings begin

step[int] interval between consequent readings

readings[array[float]] contains the values in kW

#S-m##-YYYY-MM-DD.json same as above but meter readings are at 2 minutes intervals. DD is the day of the month the readings refer to. Not always available.

Visualisation configuration files

config.json is the configuration file that instructs Joule on the location of the data files and sets some visualisation variables.

'trees.json'