Power measurement

As an IT (networking) guy, I have a lot of computer equipment that is using a lot of power.
One of my friends once said to me if they had something like the energy measurement police and you where not allowed to use more than a specific amount of energy, they would probably arrest me.
It made me wonder how much power I am actually using. To measure the amount of kWh that I am actually using per hour, day, weeks, months or even years I am using equipment of RFXCOM.

Equipment

The equipment and software to measure my power is:

• 433.92MHz RFXmitter (2-ports LAN version) with a 433.92MHz receiver (master) module (with antenna)
• 433.92MHz RFXMeter with 1 RFXPulse module
• Homeseer 2
• RFXCharts

The picture below gives you an illustration of how this should work.

What basically the story behind the picture is is that:

• The CT1021 (The energy meter that the power delivery company is installed) has an Infra Red LED that blinks
• When the Infra Red LED blinked 1000 times this means that I consumed (or all the electrical devices in my house consumed) 1 kWh of power
• I can measure the amount of blinks with the “Reflective-Optical sensor” by just sticking the sensor window on the IR LED window.
• The 433.92MHz RFXMeter with 1 RFXPulse module will count the blinks or so calles pulses and send this information using the 433.92 MHz frequency to the 433.92MHz receiver (master) module (with antenna)
• The 433.92MHz receiver (master) module (with antenna) sends the “blinks/pulses” information to Homeseer 2
• Homeseer 2 uses the RFXCharts script which generates charts based on the information (blinks/pulses) that where sent from my CT1021 energy meter

Because my CT1021 energy meter is using an IR LED I needed to make a small adjustment to the Reflective-Optical sensor. (Open the 3,5 jack plug and cut the white wire (leave the copper and blue untouched!)

Sensors

Usualy the Reflective-Optical sensor is used for other kind of meters with a rolling counter with a small mirror on it. When the mirror shows up the Reflective-Optical sensor will count that as 1 pulse and 1 just like 1000 pulses on my CT1021 means that I used 1 kWh of power, it will probably mean a specific amount of water or gas is used.Some people have a energy meter with a normal blinking light. This people need a different sensor … the Photo Sensor.

Charts

Well if everything is working as it should and Homeseer 2 is receiving the information and RFXCharts is installed and configured according to the guide you should see some charts.

My hourly power chart looks like this at the moment:

I hope you enjoyed my explanation on the energy measurment part of my overall domotica project …

Energy Costs of my Energy provider

Measuring power or energy made me wonder how much energy actually cost, so I made some phonecalls and checked out my online account of the energy provider.

It seems that I have something called dubbeltarief which means I pay 2 amounts:

• daluren 23:00 – 07:00 (weekends and nighthours and some public hollidays) = laagrarief
• normal hours 08:00 – 23:00 (weekdays) = normaaltarief

The total costs comes to:

• laagtarief = € 0,2051 per kWh
• normaaltarief= € 0,2482 per kWh

This amount is including the energy tax fee and the 19% VAT fee but exludes the Vastrecht fee and Transport fee.There are also other amounts I need to pay which comes in monthly or yearly:

• Vastrecht = € 1,99 incl 19% VAT p.m (€ 23,88 incl VAT p.y.) (The payment for invoice process and paymentprocess costs)
• Transport fee = € 182,46 incl. 19% VAT p.y. (The payment for a 3-phase connection to the energy provider (3 x 25A)

total extra yearly costs are:€ 23,88 + € 182,46 = € 206,34

In 2010 I switched from Eneco to EON and my current energy price is: vasttarief € 0,0833 per kW