HVAC Monitoring & Control System for a Residential Complex in Denmark

My project with Alkes Have in Denmark is a clear example of applying IoT to solve large-scale heat management. With 40 independent apartments, the core goal was to automate Buffer Tank and DHW control—balancing energy efficiency with maximum comfort.

To operate the building efficiently, the system had to overcome three major barriers:

• Fail-safe operation: remain stable and keep running even when the internet is down.
• Personalized demand: each apartment has different habits and preferred temperature thresholds.
• Cost optimization: reduce wasted electricity during low-demand hours or when there is no usage.

Solution: a "Smart & Resilient" 3-layer architecture

• Edge Computing: Shelly runs on-site logic so the system still operates when the internet is down.
• Orchestration: Node-RED maps data per apartment and uses MQTT Retain to restore configuration after reconnect.
• Operations: Datacake provides a centralized dashboard with manual override and timer scheduling for energy optimization.

Shelly (Edge) → Node-RED (Orchestration) → Datacake (Operations)

Edge Computing: On-site intelligence with Shelly

Acting as the on-site "nervous system", Shelly Plus 2PM combined with temperature add-ons enables:

• Autonomous operation: control scripts run directly on the device to switch valves based on real temperature—without waiting for cloud commands.
• Instant response: removes latency and reduces risk during network outages.

Local state and manual actions are available on the device level, supporting fast troubleshooting and safe overrides when needed.

Orchestration: Smart data management with Node-RED

Node-RED acts as the "conductor" for system data flows:

• Accurate identification: automatically maps each apartment's MQTT data to the correct management ID—preventing data mix-ups.
• Self-recovery: uses MQTT Retain so devices immediately receive the latest configuration after reconnect.

Operations: Centralized dashboard on Datacake

The status of all 40 apartments is brought into a single operations screen:

• Multi-level monitoring: from a building-wide view down to per-apartment temperatures and valve states.
• Flexible control: technicians can manually override or schedule timers with a few clicks.

Operator tools for energy saving and fast intervention:

• Manual control/override when needed
• Timer scheduling for Buffer Valve to reduce unnecessary runtime

Each apartment can have its own ON/OFF temperature thresholds for Buffer and DHW, allowing tailored comfort and better energy usage without changing the global logic.