Specification for a Sustainable BEMS

 

This specification outlines the requirements for an openly distributed Building Energy Management System (BEMS) designed to provide flexibility, scalability, and full interoperability. The system must feature neutral input/output (IO) hardware, non-proprietary displays, responsive web browser graphics, remote accessibility, and historic logging capabilities. It must also ensure open access to training, support, and modern standards of interoperability.

 

Why Choose an Openly Distributed BEMS?

An openly distributed BEMS offers significant advantages over proprietary systems. By using neutral hardware and software, this model ensures:

Minimization of Electrical Waste:

• Neutral IO modules and displays are not tied to specific manufacturers or controllers.
• These components can remain in place for the lifespan of the installation, even during system upgrades or migrations.
• This reduces material waste, minimizes environmental impact, and contributes to sustainability goals.

Retention of Wiring Infrastructure:

• Existing wiring diagrams and cabling infrastructure remain entirely reusable during system migrations or upgrades.
• This eliminates the need for costly rewiring or additional containment, reducing downtime and labor expenses.

Future-Proof Design:

• Neutral IO hardware can integrate easily with future master controllers, allowing for smooth system upgrades without the need to replace existing infrastructure.
• Non-proprietary displays ensure continued usability and integration with any updated system, reducing costs and complexity.

Simplified Upgrades:

• In an openly distributed BEMS, the only component that needs replacing during an upgrade or migration is the master controller.
• This avoids the extensive rewiring, equipment replacement, and re-labeling typically required in proprietary systems.

Flexibility and Cost Efficiency:

• Openly distributed systems enable competitive bidding for future service and maintenance, ensuring long-term cost savings.
• Building owners are not locked into a single vendor, offering freedom of choice and reducing dependency.

 

System Overview

 

The Building Energy Management System (BEMS) will integrate and control the building’s energy systems, including HVAC, lighting, and other energy-consuming equipment. The system must:

• Be openly distributed, avoiding vendor lock-in by using hardware and software components supported by multiple manufacturers.
• Employ neutral IO modules, capable of integration with BACnet, Modbus, and other open protocols.
• Provide a responsive, web-based graphical user interface (GUI) accessible across devices (PCs, tablets, and smartphones).
• Offer unrestricted access to training and documentation, enabling end-users to manage the system independently or via third-party support providers.
• Meet all modern interoperability standards, including BACnet/IP, Modbus TCP/IP, and REST APIs.

 

Hardware Requirements

 

Controllers:

• The system must use BACnet-compliant controllers that can integrate seamlessly with other devices from various manufacturers.
• Controllers must support at least 8 inputs/outputs (IO) per module, including: Analog Inputs (AI) and Outputs (AO).Digital Inputs (DI) and Outputs (DO).
• Controllers must allow for local control logic execution to ensure continuous operation during network outages.
• Distributed control architecture preferred, allowing flexibility in system expansions.

IO Modules:

Neutral IO hardware (e.g., iSMA Expansion Modules) must be used, avoiding proprietary restrictions.

IO modules must support:

• Analog signals (0–10V).
• Digital signals (dry contacts or pulses).
• Temperature, CO₂, humidity, and differential pressure sensor integration.
• Modular IO design to allow scalable installations based on project needs.

Display Hardware:

• Non-proprietary HMIs with web-enabled capability.
• Minimum display size: 10 inches for onsite panels.
• Central PC workstation to be either Controller Web Browser linked or pre-installed BEMS Supervisor software.

Wiring Infrastructure:

• Any new or existing wiring infrastructure must remain fully compatible with the BEMS design .
• Limited or no additional cabling, re-labelling, or containment should be required during future upgrades or migrations.
• All wiring diagrams must be provided or updated with as-built documentation for future compatibility.

 

Software Requirements

 

Graphical User Interface (GUI):

• Fully responsive GUI compatible with modern web browsers (e.g., Chrome, Edge, Safari).
• Must provide mobile-friendly designs for seamless access on smartphones and tablets.
• Support neutral graphic tools for intuitive operation and navigation.

Control Logic and Strategies:

The system must support advanced control strategies, including but not limited to:

• Demand-Controlled Ventilation (DCV): Adjust ventilation based on real-time occupancy (e.g., CO₂ levels).
• Night Purge: Utilize cooler outdoor air for preconditioning during summer nights.
• Optimized Start/Stop: Calculate optimal HVAC operation start and stop times.
• Free Cooling: Automatically enable when outdoor conditions are favorable.

Historical Logging:

• Trend data for all critical points must be logged for at least 12 months.
• Logs must be exportable in standard formats (e.g., CSV, Excel) for third-party analysis.
• System must support local and cloud-based storage options for redundancy.

Alarming:

• Configurable alarms for faults, out-of-range conditions, or equipment failures.
• Email and SMS notifications for critical alarms, configurable by user.

Integration and Interoperability:

Must support integration with third-party systems using:

• BACnet/IP and BACnet MSTP for HVAC.
• Modbus TCP/IP for plant equipment.
• RESTful APIs for custom cloud integrations.
• MQTT for IoT applications.
• Ability to integrate renewable energy systems (e.g., solar, battery storage).

Remote Accessibility:

• Provide secure remote access via a web browser with multi-factor authentication.
• Support HTTPS encryption for all remote communications.

 

Maintenance and Scalability

 

Maintenance:

• The BEMS must include a self-diagnostic feature for controllers, IO modules, and network communications.
• Maintenance tools must be accessible to third-party providers.
• Open licensing required for software, avoiding proprietary lock-in.

Scalability:

• Modular system design to allow easy additions of controllers, IO modules, and sensors.
• System must support up to 500 devices without hardware or software upgrades.

Compliance with Modern Standards:

• Full compliance with BS EN 15232 for energy performance of buildings.
• Meet cybersecurity standards outlined in ISO/IEC 27001.
• Interoperability with renewable energy solutions in line with Net Zero goals.

 

Summary of Benefits

 

1. Minimized Waste: IO modules, screens, and existing wiring infrastructure are retained, avoiding unnecessary replacement during migrations or upgrades.
2. Cost Efficiency: Only the master controller is replaced during migrations or upgrades, reducing both material and labor costs.
3. Future-Proof: Neutral hardware ensures long-term compatibility with new evolving technologies.
4. Open Access: Full system transparency with unrestricted training, support, and documentation.
5. Simplified Upgrades: No need to replace wiring infrastructure, wiring documentation or displays, minimising environmental and financial costs.