BMS in Valencia municipal buildings: technical specification, execution and results

The starting point: buildings without coordinated management

The Infrastructure Department of Valencia City Council contacted us with a problem common to most public administration buildings: facilities built in different decades, each with its own HVAC, lighting and access control systems, run completely independently and with no kind of centralised supervision.

The project covered five buildings: the Benimaclet Municipal Public Library, the offices of three town halls in the L'Horta Sud county and a multipurpose social services building in central Valencia. Together, more than 12,000 m² of managed technical floor space.

The starting situation had three well-defined problems. First, opaque energy consumption: with no granular metering by zone or by system, it was impossible to know which part of the building consumed the most or in which time slots. Second, reactive operation: maintenance acted on faults that had already occurred, not on preventive alerts. Third, a complete lack of integration: HVAC, lighting and energy meters operated as silos with no communication between them.

Why Beckhoff TwinCAT 3?

The choice of control hardware and software was one of the most significant technical debates of the project. The buildings had very different requirements from each other: the library called for very precise lighting management with time profiles and presence detection, while the town halls prioritised HVAC control and remote telemetry. The social services building added access control and CCTV to the mix.

We chose Beckhoff TwinCAT 3 for several reasons that fit the customer's profile well:

• Native BACnet/IP and KNX support: Beckhoff offers certified TwinCAT libraries for both protocols, which were the predominant ones in the existing HVAC and lighting equipment. We didn't need extra gateways for most of the integration.
• Modular scalability: the EtherCAT I/O architecture allows energy metering, temperature input or control output modules to be added without redesigning the cabinet. A clear advantage for a customer planning to extend the BMS to more buildings in the future.
• TwinCAT HMI as a unified visualisation layer: instead of relying on third-party SCADAs with per-point licensing, TwinCAT HMI allowed an embedded web development accessible from any browser with no extra software at the operator workstation.
• Lifecycle cost: for a public-sector customer with a tight budget and periodic tendering, the absence of recurring licensing per number of tags or variables was a decisive argument.

System technical architecture

The BMS design was structured in three clearly differentiated layers, following the classic building automation model adapted to public administration requirements.

Field layer: existing sensors and actuators

In each building we audited the existing equipment before defining what had to be replaced and what could be integrated directly. The vast majority of HVAC units (fancoils and AHUs from various manufacturers) had BACnet/IP controllers or could be enabled via the manufacturer's own communication modules. The library's lighting installation already had a partially wired KNX bus but no active programming.

We installed Beckhoff EL3453 energy metering modules in each building's main electrical cabinets to obtain active power, reactive power and power factor measurement per circuit. This information, together with temperature and CO₂ sensors in zones with variable occupancy, formed the basis of the adaptive control system.

Control layer: Beckhoff PLCs per building

Each building has its own Beckhoff CX5140 controller running TwinCAT 3 in real time. This controller acts as the building's BACnet master, manages all local logic — schedules, occupancy profiles, HVAC sequences, lighting control by presence and natural light level — and exposes an OPC-UA server toward the central supervision layer.

The control logic was programmed entirely in Structured Text (ST) per IEC 61131-3, with reusable function blocks for the common routines: adaptive setpoint management, free-cooling algorithms, staggered start-up logic to reduce demand peaks and alarm management with local history.

Supervision layer: central server and TwinCAT HMI

A centralised supervision server with TwinCAT HMI Server was installed at the customer's main premises, aggregating data from the five buildings via OPC-UA. From this platform, the maintenance lead has a web dashboard with:

• Real-time view of the status of every system by building and by zone.
• Energy dashboard with cumulative consumption, breakdown by system (HVAC, lighting, others) and cross-building comparison.
• Centralised management of schedules and occupancy profiles (holidays, reduced hours, special events).
• Alarm panel with email notification and incident logging.

The dashboard is accessed via web browser with no extra client required, with username/password authentication and differentiated roles for operators and administrators.

BACnet/IP and KNX integration: the details that matter

Protocol integration was the most technically delicate part of the project, especially in the town halls, where the HVAC equipment came from three different manufacturers with BACnet implementations of varying quality.

The first challenge was BACnet device discovery. Not all equipment had a clean implementation of the protocol: some presented undocumented proprietary object types, others required polling at specific intervals to avoid overloading their embedded CPU. We solved this with an assisted discovery process and object-by-object validation before incorporating them into the BMS data model.

For the library's KNX installation, the work was different. The physical bus was wired but had no active programming. We downloaded the actuator configuration from ETS, identified the group addresses for each circuit and luminaire, and mapped those addresses to TwinCAT variables via the TF6700 (TwinCAT KNX) module. The result was lighting control with continuous dimming, time-based profiles, presence detection and automatic adjustment based on natural light levels measured by photocells on the façade.

Results after six months of operation

The system has been in stable production since October 2025, with continuous supervision from the central panel and no major incidents since commissioning.

The 28% energy saving comes mainly from two factors: eliminating HVAC and lighting operation outside real occupancy hours (previously routine in the three town halls, where systems were left on overnight and at weekends) and the implementation of free-cooling algorithms in the buildings with greater thermal mass.

The 41% reduction in out-of-hours HVAC running not only impacts electricity consumption, but also mechanical wear on the equipment. The Department's maintenance lead estimates that the useful life of the HVAC units will have been significantly extended thanks to this single factor.

As for operations, the change most valued by the maintenance team has been early anomaly detection. Before the BMS, a faulty heat pump or a circuit drifting in temperature would go unnoticed until the problem was visible. Now, the system raises an alarm in minutes when a variable deviates from the expected range, allowing several issues to be resolved before they affected user comfort or escalated into bigger faults.

Lessons learned

This project left a few conclusions that we now apply systematically on every BMS project in existing buildings:

• The on-site audit is not optional. In none of the five buildings did the available documentation faithfully reflect the real state of the installation. Spending time inventorying and verifying every piece of equipment before designing the architecture avoids costly surprises during execution.
• BACnet isn't BACnet. The variability in BACnet implementation quality between manufacturers is greater than having the protocol in common would suggest. Allowing time for per-device validation and adjustment is essential.
• Maintenance team training defines real success. A powerful BMS used poorly produces mediocre results. We invested three days of hands-on training with the Department's team, and the difference in how the system is used is noticeable.
• Schedules are the most-used feature. More than dashboards or alarms, the management of occupancy schedules adapted to the reality of each building (local holidays, events, school breaks) is the function the customer uses every day and the one with the greatest direct impact on consumption.

Public procurement: how this project was awarded

The five buildings of this project were procured through minor contracts by the Valencian local administration, under article 118 of Law 9/2017 of Public Sector Contracts (LCSP). Each building was treated as an independent intervention, with its own file and specific technical specification, which kept each contract within the €15,000 ex-VAT threshold for minor service contracts.

The CPV code used in the specifications was 71321000 (Engineering services for building installations), supplemented with 71314000 (Energy engineering services). The technical specification included in every case: description of the proposed solution, justification for the technology choice, technical specifications of the equipment, execution plan, test protocol and verifiable energy-savings estimate.

Technical documentation delivered for each building

One of the things public administration values most as a customer is the thoroughness of the technical documentation. On this project we delivered, for each building:

• Project technical specification with a detailed description of the solution, justification of the chosen architecture and specifications of the equipment installed.
• Drawings and installation schematics updated to the as-built state after execution: BACnet/IP network diagram, controller and measurement-point locations.
• User and operations manual tailored to the municipal maintenance staff profile: schedule management, alarm interpretation, generation of consumption reports.
• FAT/SAT test protocol signed by the Department's technical lead, documenting the functional verification of every control point.
• CE Declaration of Conformity for the control electrical cabinet under the Low Voltage Directive and IEC 61439.
• Backup and source code of the program TwinCAT 3 delivered on physical media and via repository, ensuring the administration has full ownership of the control software.
• Energy savings report verified with real data from the first year of operation, useful for justifying the investment in internal audits and to control bodies.

Applicable technical standards in BMS projects for public buildings

Building automation projects in the public sector must consider a wider regulatory framework than in the private sector:

• RITE (Spanish Regulation on Thermal Installations in Buildings): requires control and regulation systems for thermal installations. The BMS is the technical tool that enables compliance with RITE on zoning, regulation and consumption logging.
• RD 56/2016 on Energy Efficiency: obliges large organisations (and public administration is one) to carry out energy audits every 4 years. A BMS with historical data makes these audits much easier.
• EU Directive 2023/1791 on Energy Efficiency: sets a target of 1.9% annual reduction in public-sector energy consumption. Buildings with a BMS demonstrate compliance objectively and with evidence.
• IEC 62443 (OT Cybersecurity): public-building control systems, especially those connected to municipal corporate networks, must consider cybersecurity. We implement network segmentation and industrial VPN on every public-administration project.
• EN ISO 52120 (Building automation and energy efficiency): European standard that classifies buildings by automation level (classes A-D). The buildings on this project moved from class D to class B after the BMS was deployed.

Does your organisation manage public or industrial buildings?

If you have facilities with HVAC, lighting or energy systems that don't talk to each other, or you simply have no visibility of what each building consumes and when, a well-implemented BMS can radically change the situation. At Bluemation we work with Beckhoff, Siemens, Schneider and other manufacturers depending on the context of each project, and we accompany the whole process from the initial audit to team training.

We prepare the full technical documentation needed for tenders and minor contracts: technical specification, technical prescriptions document, equipment specifications and test protocol. Tell us about your case and we'll analyse with no commitment which architecture makes most sense for your situation.