Mjölnir: The Movie

Because of the great interest in Mjölnir, we decided to maka a short introduction video providing a walk through the system.

Find out more about the idea behind the system in

A. Monacchi, F. Versolatto, M. Herold, D. Egarter, A. M. Tonello, and W. Elmenreich. An open solution to provide personalized feedback for building energy management. ArXiv preprint arXiv:1505.01311, 2015.

or download the software at mjoelnir.sourceforge.net.
 

Building Management with Mjölnir

We recently announced the release of the stable version 0.2 of our open source energy management system Mjölnir at http://mjoelnir.sourceforge.net.

While the tool targeted so far mostly "disaggregated" device-level energy and power usage, we have now introduced full support for circuit-level measurements (buildings, rooms) which unlocks a considerable potential for further data analysis.

The DIN-RAIL module running the measurement system

As most of energy meters use the industrial automation system ModBus, we have been looking for possible shields to extend our open hardware solution with RS485 communication. We finally selected this RPi hat from Libelium while the meter is the Carlo Gavazzi EM24. The implementation is eased by the Libelium ArduPi library, which makes the C code written for Arduino compatible with the Raspberry Pi. The data is then being sent to our servers through a REST interface.

The overall component shown on the picture is therefore a low cost solution able to retrieve remote measurements via the RS485/ModBus and the USB/ZigBee network. This opens for the future integration of other measurement units, such as water and gas meters.

The support of circuit-level measurements required changes on the Mjölnir system.

The system is now organised in buildings, rooms and devices. A circuit is described by its ID and can be associated to a single building or room.
As usual, the code of the gateway is available on SourceForge, along with the dashboard system.

Bibliography:

1. A. Monacchi, F. Versolatto, M. Herold, D. Egarter, A. M. Tonello, and W. Elmenreich. An open solution to provide personalized feedback for building energy management. ArXiv preprint arXiv:1505.01311, 2015.

MJÖLNIR - The Open Source Energy Advisor

The interface 0.2

We are glad to announce the stable release 0.2 of our open source energy management system at http://mjoelnir.sourceforge.net.

Mjölnir provides an open platform where different energy consumption  feedback mechanisms can be implemented and assessed.

The system is one outcome of the MONERGY project, an Interreg research project that explores the use of home energy management systems to foster alteration of consumption patterns and achieve better utilisation of local energy sources. In particular,  we addressed residential settings in Carinthia (Austria) and Friuli-Venezia Giulia (Italy).

We identified common electrical devices and analysed the penetration of renewable energy [1], as well as user's attitude towards smart homes [2]. A measurement campaign was then carried out in 8 selected households, to track power consumption of individual loads at 1Hz for over 1 year. Main outcome was the GREEND dataset [3], openly available here. 

The energy advisor widget

The dataset was then analysed to gain further insights into energy consumption behaviour in the regions [4]. In particular, policies were formulated to improve energy efficiency, namely: i) shedding of standby losses, ii) postponement to off-peak periods, iii) replacement with more efficient appliances, and iv) operation curtailment.

An estimation of benefits yield by those policies was computed using data from the GREEND dataset, which showed a potential of up to 34% of savings. However, while these policies have a general validity, their benefits can be extended to a larger area by exploiting the functionalities of the Mjölnir framework. To this end, we implemented an energy advisor widget which displays the list of advices and allows users for acceptance and rejection. Each candidate advice is computed based on actual device usage events and energy costs, while a limited number of advices is returned based on user's preferences [5].

The MJÖLNIR system is part of a larger solution consisting of:

• an aggregate power meter, measuring active power, such as the YOMO open hardware meter [6]
• an appliance-level monitoring system, such as the OpenEnergyMonitor [7], or a load disaggregation unit [8]
• the energy management system, consisting of a RESTful webservice and dashboard (Mjölnir) and a mobile application [9]

We expect the tool to be beneficial for both individuals and researchers carrying out field tests on persuasive technologies, whose contribution is particularly encouraged.

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References:

1. A. Monacchi, W. Elmenreich, Salvatore D'alessandro, and A. Tonello. Strategies for domestic energy conservation in Carinthia and Friuli-Venezia Giulia. In Proceedings of the 39th Annual Conference of the IEEE Industrial Electronics Society (IECON 2013). IEEE, November 2013.
2. T. Khatib, A. Monacchi, W. Elmenreich, D. Egarter, S. D'Alessandro, and A. M. Tonello. European end-user’s level of energy consumption and attitude toward smart homes: A case study of residential sectors in Austria and Italy. Energy Technology & Policy, 1(1):97–105, 2014.
3. A. Monacchi, D. Egarter, W. Elmenreich, S. D'Alessandro, and A. M. Tonello. GREEND: An energy consumption dataset of households in italy and austria. In Proc. IEEE International Conference on Smart Grid Communications (SmartGridComm'14), Venice, Italy, 2014.
4. WiTiKee and Lakeside Labs. Validation and analysis of results. Monergy 4th project deliverable, 2015.
5. A. Monacchi, F. Versolatto, M. Herold, D. Egarter, A. M. Tonello, and W. Elmenreich. An open solution to provide personalized feedback for building energy management. ArXiv preprint arXiv:1505.01311, 2015.
6. C. Klemenjak, D. Egarter, and W. Elmenreich. YOMO - The arduino based smart metering board. In Proc. Energieinformatik, Zurich, Switzerland, 2014.
7. OpenEnergyMonitor http://openenergymonitor.org/emon/
8. D. Egarter, V. P. Bhuvana, and W. Elmenreich. PALDi: Online load disaggregation via particle filtering. IEEE Transactions on Instrumentation and Measurement, pages 1–11, 2014.
9. A. Monacchi and W. Elmenreich. Insert-coin: turning the household into a prepaid billing system. In Poster Abstract, 5th ACM Workshop On Embedded Systems For Energy-Efficient Buildings. ACM, November 2013.

Quick intro to the Open Source Renewables Alternative Power System Simulation (RAPSim)

In a previous blogpost, we introduced RAPSim, a free open source power system simulator with a graphical interface. RAPSim was developed at the Alpen-Adria-Universität Klagenfurt within the Lakeside Labs project Smart Microgrid. The main architect of RAPSim, Manfred Rabl-Pöchacker now produced video giving an ultra-fast introduction to the tool. Got three minutes? Here is the video:



Interested? RAPSim can be freely downloaded at rapsim.sourceforge.net.
If you want to learn more about RAPSim, here is a paper about RAPSim:

M. Pöchacker, T. Khatib, and W. Elmenreich. The microgrid simulation tool RAPSim: Description and case study. In Proceedings of the IEEE Innovative Smart Grid Technologies Asia (ISGT-ASIA'14), Kuala Lumpur, Malaysia, 2014. IEEE.

YoMo - The Open-Source Smart Meter Platform

YoMo board with electronic components

We introduce our recently developed smart metering board called YoMo (You only meter once). The board is an extension board compatible to Arduino boards. YoMo offers features such as:

• measuring active, reactive, apparent power, current, and voltage
• switching loads up to 20A,
• adjustable sampling frequency and 
• open-hardware design and open-source firmware

YoMo PCB before soldering

The smart meter platform, provided as open hardware, is designed with a connector interface compatible to the Arduino platform, thus opening the possibilities for smart meters with flexible hardware and computation features, starting from low-cost 8 bit micro controllers up to powerful single board computers that can run Linux. The metering platform features a current transformer which allows a non-intrusive installation of the current measurement unit. The suggested design can switch loads, offers a variable sampling frequency, and provides measurement data such as active power, reactive and apparent power. Results indicate that measurement accuracy and resolution of the proposed metering platform are sufficient for a range of different applications and loads from a few watts up to five kilowatts.

YoMo is further described in this paper

C. Klemenjak, D. Egarter and W. Elmenreich. YOMO - The Arduino based Smart Metering Board. Energieinformatik'14, Zurich, Switzerland, 2014

Further information can be found at the YoMo project homepage: http://yomo.sourceforge.net/

The Renewable Alternative Power System Simulator - RAPSim

An open simulation software for Micro Grids

It is not necessary to stress all the challenges that come allong with wide range integration of renewables into the power grid at this article. You easily find this somewhere else, in this blog or at another source in the web. But I want to focus your attention on a tool that can help to deal with this challenges and work torwards solutions. It is a lot on matching climate dependent production with the personal demand which is currently noticed only in average. The various influences on residential load profiles are diverse and include weather conditions, availability of other resources, personal habits and also social phenomenas. This variaty is a reason why Marija Ilic speaks of just-in-time and just-in-place services in the conntext of Smart Micro Grids. 

Developing of or researching on such services requires a flexible simulation tool with possibly high usability. This is exactly what RAPSim is aiming at. RAPSim has been developed at the Alpen-Adria-Universität Klagenfurt within the Lakeside Labs project Smart Microgrid and was presented in front of interested audience at the ISGT Asia - 2014 conference in Kuala Lumpur in May 2014. Since then the software project is downloadable for free at Sourceforge.net. 

Connected Smart Grid Objects 

The simulation field is a lattice where the user designs a scenario by placing different "grid objects", e.g., houses, wind turbines, PV panels, etc. Each of the objects can have a model which does all the inner-object calculations. Algorithms handle grid-wide interactions. User-defined models can extend  algorithms for the grid and/or models for the grid objects. RAPSim provides the interface with following functions:

• A graphical interface to create the intended scenarios and to control the simulator functions.
• Functions to save and load simulation scenarios in a generic xml format.
• A time thread that models time of day and day of the year and handles up to minute resolution.
• Generation of output files in csv-format. Object parameters can be selected to be written into a file at each time step.
• Weather simulation which can be done via stochastic models or simulated by measured data.
• Topological grid analysis that collects objects of the same bus in a list and aggregates their parameter values.
• Administration of algorithms for grid-wide calculations.
• Administration of object specific models that can be easily implemented by the user.

The software is written in Java and provided with the source code so that it can be imported into a Java IDE such as eclipse. The development of the software is still ongoing. Try it out and give us feedback by adding a comment or sending a ticket to helps us to further improve it. Please spread the news about the tool, while we will do the best on our part so that onces RAPSim may become a synonym for rapid simulation in the field of mirco grids.
Once more here the link to the sourceforge page.

Publications on RAPSim (with links to fulltext PDF):

M. Pöchacker, T. Khatib, and W. Elmenreich. The microgrid simulation tool RAPSim: Description and case study. In Proceedings of the IEEE Innovative Smart Grid Technologies Asia (ISGT-ASIA'14), Kuala Lumpur, Malaysia, 2014. IEEE.