Saudi Arabia Building Automation System | SENTRADO
A detailed case study of SENTRADO's industrial automation solution delivering measurable results for building automation operations in Saudi Arabia.
Project Background & Objectives
SENTRADO delivered an integrated building management system (BMS) for a large commercial complex in Riyadh, Saudi Arabia, comprising four office towers, a retail podium, and underground parking facilities totaling over 180,000 square meters of conditioned space. The client, a major real estate developer, required a unified platform to manage HVAC, lighting, energy metering, and access control across all buildings while meeting Saudi Arabia's stringent energy efficiency regulations and Vision 2030 sustainability targets.
The extreme climate of Riyadh — where summer temperatures regularly exceed 45°C — makes air conditioning the single largest energy consumer in commercial buildings. The developer needed a BMS that could aggressively optimize cooling delivery without compromising tenant comfort, while also providing the granular energy data required for Saudi Energy Efficiency Center (SEEC) reporting and green building certification.
SENTRADO's scope included BMS panel manufacturing, DDC controller supply and programming, central workstation software, integration with third-party systems (chiller plant, lighting, elevators, fire alarm), and the commissioning of all control sequences across the complex.
Problems We Had to Solve
1. Extreme Climate Cooling Load
Riyadh's 45°C+ summer temperatures create massive cooling loads that vary significantly throughout the day and across building orientations. Fixed-schedule HVAC operation was wasting energy during low-occupancy periods while occasionally failing to maintain setpoints during peak afternoon heat.
2. Multi-System Integration
The complex uses different vendors for chillers (Carrier), lighting control (Philips Dynalite), elevators (KONE), and fire alarm (Siemens Cerberus). The BMS needed to communicate with all of these using BACnet/IP, Modbus, and proprietary protocols without requiring replacement of any existing systems.
3. Energy Reporting Compliance
SEEC regulations require detailed energy consumption reporting with sub-metering at the floor and tenant level. The existing electrical meters had no communication capability and had to be retrofitted with pulse or Modbus output modules.
4. Tenant Comfort vs. Efficiency
The developer needed to reduce energy costs while maintaining strict comfort standards (23±1°C, 50±5% RH) to satisfy premium commercial tenants. This required demand-based ventilation, optimal start/stop, and enthalpy economizer strategies.
5. Scalability for Future Expansion
The client planned a fifth tower within three years. The BMS architecture needed to accommodate additional controllers, points, and graphics without major reengineering or server replacement.
Our Approach & System Architecture
SENTRADO designed a BACnet/IP-based BMS using Siemens DDC controllers deployed throughout the complex, with each building having its own automation-level network connected to a central BMS server via the building's IP backbone. The system architecture follows the three-level BMS model: field level (sensors and actuators), automation level (DDC controllers), and management level (central workstations and web clients). This segmentation ensures that local control continues even if the central server or network is unavailable.
HVAC optimization strategies include optimal start/stop based on outdoor air temperature and building thermal mass, demand-controlled ventilation using CO2 sensors in occupied zones, chilled water reset based on actual cooling demand, and supply air temperature reset. The chiller plant is controlled as an integrated system with sequencing that maximizes chiller efficiency by matching operating chillers to load, controlling condenser water temperature based on wet-bulb conditions, and balancing pump speeds using differential pressure control.
Lighting integration was achieved via a BACnet gateway to the Philips Dynalite system, enabling scheduled lighting control, occupancy-based switching, and daylight harvesting in perimeter zones. Energy meters were retrofitted with Modbus communication modules, providing tenant-level sub-metering with automated billing data export. The BMS server runs Desigo CC with a web client that allows facility managers to monitor and control the complex from any browser, with dashboards showing real-time energy performance, comfort metrics, and equipment status.
System Architecture Highlights
- Siemens DDC controllers on BACnet/IP across all buildings
- Integrated chiller plant optimization with load-matching sequencing
- Demand-controlled ventilation based on CO2 sensing
- Optimal start/stop and thermal mass learning algorithms
- BACnet gateway integration with lighting, elevator, and fire systems
- Tenant-level energy sub-metering with automated billing export
- Desigo CC management platform with web client access
- Scalable architecture designed for fifth tower addition
System Parameters & Configuration
| BMS Platform | Siemens Desigo CC |
| DDC Controllers | 24 × Siemens PXC compact controllers |
| Total BMS Points | 4,200+ (AI: 680, AO: 320, BI: 1,800, BO: 1,400) |
| Communication Protocol | BACnet/IP / Modbus TCP / KNX |
| Management Workstations | 2 × Desigo CC + 5 web clients |
| Control Panels | 8 × IP44 DDC panels |
| Buildings Controlled | 4 towers + retail podium + parking |
| Total Floor Area | 180,000+ m² |
| Chiller Integration | Carrier AquaEdge via BACnet gateway |
| Lighting Integration | Philips Dynalite via BACnet/IP |
| Energy Meters | 120+ sub-meters with Modbus output |
| Energy Savings | 25% (verified post-occupancy) |
Key Components & Hardware
Siemens PXC24 DDC
S55376-C125
BACnet/IP compact DDC controller
Siemens PXC16 DDC
S55376-C122
Smaller zone DDC controller
Desigo CC Server
S55801-Y120
BMS management platform
QFA3171 Room Sensor
S55720-S171
Temp/RH/CO2 room sensor
QBE3000 Pressure
S55720-S121
Differential pressure sensor
Siemens RAB11 Actuator
S55720-S221
Damper actuator for VAV boxes
BACnet Router
S55801-Y115
BACnet/IP to MSTP router
SITOP PSU100C
6EP1332-5BA10
24V DC power supply for DDC panels
Project Phases
BMS Design
6 weeksPoint schedule, sequence of operations, network plan
Panel Manufacturing
4 weeks8 DDC panels assembled and tested
DDC Programming
8 weeksHVAC, lighting, energy sequences and graphics
Third-Party Integration
4 weeksGateway configuration for chiller, lighting, elevators
Installation
8 weeksCoordinated with building construction schedule
Commissioning
6 weeksPoint-to-point checks, sequence verification, tuning
Optimization Period
12 weeksSeasonal tuning, tenant move-in support
Training & Handover
2 weeksFacility team training, as-built documentation
Measurable Outcomes
Performance data verified after system commissioning and sustained operation.
Verified reduction in HVAC energy consumption
Temperature maintained within ±1°C setpoint
Tenant-level energy granularity
Single platform for entire complex
Before vs After: Quantified Comparison
| Metric | Before | After | Change |
|---|---|---|---|
| HVAC energy consumption | Baseline (fixed schedule) | 25% verified reduction | −25% |
| Temperature control | ±3°C fluctuation | 23°C ±1°C consistent | Tighter |
| Energy metering | Building-level only | 120+ tenant sub-meters | Granular |
| Building management | 4 separate BMS systems | 1 unified platform | Consolidated |
| Maintenance response | Reactive, tenant complaints | Predictive, automated alerts | Proactive |
Data based on project commissioning reports and sustained operational measurements. Client name available under NDA.
Bottom Line Impact
The delivered automation system exceeded all performance targets specified in the contract, achieving higher throughput, lower energy consumption, and improved product quality compared to the baseline operation. The client reported full return on investment within the projected payback period and has since engaged SENTRADO for additional plant expansion phases.
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