BEMServer,
an open source solution

BEMServer is an open source initiative to gather all developers and software experts of building-oriented services around one project to ease the deployment of their solutions.

The concept of building as a platform of services is becoming more and more popular. Making building data available is the initial and mandatory step to do so. But just like for smartphones or computers, we do not believe the added value is brought by the tool itself; the additional value is brought by services delivered to the clients.

This is the reason why BEMServer is fully open source as a live and constantly updatable solution to the integration of services for a monitored building.

Build your Building Operating System on top of BEMServer

Our developments are fully in line with the concept of Building Operating System (BOS). Additionally, we make use of the most advanced and standards technologies of the world wide-web so that non-building experts can still develop their own services:

• REST APIs which are also fully documented
• Linked data to store building information, and to make BEMServer BIM-compatible.

In a building context, the data to be managed are heterogeneous by nature:

• sensors and meters send time series (i.e. list of pairs timestamps/values);
• incidents or information regarding the building in exploitation (such as a temperature threshold reached, an abnormal energy consumption...) which we call events;
• and what we call the metadata which are descriptive elements of the building that allow contextualization of both timeseries and events.

BEMServer is structured according to three main layers

A storage solution making use of 3 different technologies, one for each of the different data categories handled :

• SQLLite to store events
• HDF5 to store time series
• Apache Jena to store the metadata

The preprocessing layer so that all the data can be preprocessed before being stored, or before being presented to the third-party services. Current preprocessings are:

• Unit conversion, that ensures a uniform and comparable presentation of the data;
• Time series resampling, so that data coming from different and unsynchronized data sources can be compared;
• Time series operation: finding the maximal/minimal value captured by a sensor between two dates, computing the mean value, or sum value;
• Data cleansing: sensors and meters are subject to errors, and raw value obtained are not always reliable. Some data may be missing, some others may have derived from the initial calibration of the sensor… This data cleansing layer offers basic tools to detect such missing and outlier values, and to interpolate values based on their history.

The presentation layer is basically made of standard REST APIs to ease the integration of services. The complexity of the solution is fully hidden behind standards APIs. Additionally, BEMServer APIs are secured using a Role Based Access Control, which enables one to deploy a single instance of BEMServer for different sites and clients while ensuring no data could go to the wrong client.

As an open source solution, everybody can contribute to the consolidation and the development of additional functionalities to BEMServer. In a fast-moving digital world, we believe open solution is the answer to bring the best solutions to our final clients.

About BEMServer License