# Demand Response and Grid-Interactive Building Controls ## Overview Demand Response (DR) programs allow building operators to reduce electrical consumption during peak grid periods in exchange for financial incentives. Grid-Interactive Efficient Buildings (GEBs) take this further by dynamically adjusting loads to support grid stability. This guide covers DR program types, implementation in BAS, OpenADR protocol, and measurement and verification. ## What is Demand Response? Demand response is a voluntary reduction in electricity consumption during peak demand periods, typically triggered by utility signals. Buildings receive advance notice (minutes to hours) and reduce load through HVAC setpoint adjustments, lighting reductions, and equipment staging changes. ### DR Program Types | Program Type | Trigger | Response Time | Duration | Typical Incentive | |---|---|---|---|---| | Peak Shaving | Utility signal at system peak | 1-4 hours notice | 2-6 hours | $50-200/kW/year | | Load Shifting | Time-of-use pricing | Scheduled | Daily | Rate arbitrage | | Frequency Regulation | Grid frequency deviation | Seconds | Minutes | $15-40/MW/hour | | Emergency DR | Grid emergency | 30 min notice | 2-4 hours | $500-1000/MW/event | ## OpenADR Protocol OpenADR (Open Automated Demand Response) is the standard protocol for communicating DR signals between utilities and buildings. ### Architecture ```mermaid graph LR A[Utility/ISO] -->|DR Signal| B[OpenADR VTN Server] B -->|Event Notification| C[Building VEN Client] C -->|Control Commands| D[BAS Controller] D -->|Setpoint Changes| E[HVAC Equipment] D -->|Shed Commands| F[Lighting Systems] C -->|Telemetry| B B -->|Settlement Data| A ``` **VTN** (Virtual Top Node): Utility-side server that issues DR events. **VEN** (Virtual End Node): Building-side client that receives events and reports compliance. ### OpenADR Event Structure ```xml DR-2026-0215-001 SIMPLE MODERATE 2026-02-15T14:00:00Z PT4H ``` ## Implementing DR in BAS ### Pre-Cooling Strategy The most effective DR strategy for commercial buildings. Cool the building below normal setpoint before the DR event, then allow temperature to drift up during the event. **Sequence:** ``` Phase 1: Pre-Cool (2 hours before event) - Lower cooling setpoint by 2-4F - Run chillers at maximum capacity - Charge thermal mass Phase 2: DR Event Active - Raise cooling setpoint by 4-6F from normal - Reduce fan speeds to 70% - Shed non-critical lighting 30% - Disable reheat coils Phase 3: Recovery (after event) - Gradually return to normal setpoints over 30-60 min - Stagger equipment restart to avoid demand spike - Resume normal scheduling ``` ### Load Shedding Priorities | Priority | Equipment | Typical Reduction | Comfort Impact | |---|---|---|---| | 1 (First) | Non-critical lighting | 30-50% | Low | | 2 | HVAC setpoint adjustment | 20-30% of HVAC load | Moderate | | 3 | Fan speed reduction | 10-15% | Low-Moderate | | 4 | Chiller staging | 15-25% | Moderate | | 5 (Last) | Elevator operations | 5-10% | High | ### BAS Programming Example (Niagara) ``` // DR Event Handler IF DR_Signal = MODERATE THEN Cooling_SP_Offset = +4.0F Lighting_Shed = 30% Fan_Speed_Max = 70% Reheat_Enable = FALSE ELIF DR_Signal = HIGH THEN Cooling_SP_Offset = +6.0F Lighting_Shed = 50% Fan_Speed_Max = 60% Reheat_Enable = FALSE Chiller_Stage_Limit = N-1 ELIF DR_Signal = NORMAL THEN // Recovery mode Cooling_SP_Offset = 0.0F Lighting_Shed = 0% Fan_Speed_Max = 100% Reheat_Enable = TRUE ENDIF ``` ## Measurement and Verification ### Baseline Calculation DR performance is measured against a baseline (what consumption would have been without the DR event). **IPMVP Approach:** ``` Baseline_kW = Average of 10 similar non-event days Adjustment = Weather normalization (outdoor temp correlation) DR_Reduction = Baseline_kW - Actual_kW during event Savings($) = DR_Reduction(kW) x Event_Duration(hrs) x Incentive_Rate($/kWh) ``` ### Trending Requirements | Point | Interval | Purpose | |---|---|---| | Building total kW | 1 min | Verify load reduction | | Chiller kW | 1 min | HVAC component | | Lighting kW | 5 min | Lighting component | | Zone temperatures | 5 min | Comfort monitoring | | Outdoor temperature | 5 min | Weather normalization | ## Grid-Interactive Efficient Buildings (GEB) GEB extends DR to continuous grid interaction through thermal energy storage (ice/chilled water), battery energy storage systems, electric vehicle charging management, and solar PV with smart inverters. ### GEB Architecture ```mermaid graph TB A[Grid Signal] --> B[Building Energy Management] B --> C[HVAC Thermal Storage] B --> D[Battery Storage] B --> E[EV Charging] B --> F[Solar PV + Inverter] B --> G[Lighting Controls] C -->|Charge/Discharge| H[Building Load] D -->|Charge/Discharge| H E -->|V2B/V2G| H F -->|Generation| H G -->|Shed/Shift| H H -->|Net Load| A ``` ## Occupant Communication **Before DR Event:** - Email notification 24 hours ahead - Digital signage in lobbies - Building app push notification **During Event:** - Display current DR status on dashboards - Show estimated end time - Provide comfort override option (limited) **After Event:** - Share results (kW reduced, incentive earned) - Thank occupants for participation ## Common Pitfalls - **Baseline Errors:** Using wrong comparison days inflates or deflates savings - **Rebound Effect:** Post-event demand spike from simultaneous equipment restart; stagger recovery - **Comfort Complaints:** Always communicate with occupants before events - **Weather Sensitivity:** Hot days have highest DR value but also highest comfort risk - **Equipment Limits:** Do not shed critical systems (data centers, labs, operating rooms) ## Annual Savings Estimate **200,000 sqft Office Building:** - Peak shaving: 15-20 events/year x 200 kW reduction x 4 hrs = 12,000-16,000 kWh - Incentive: 200 kW x $100/kW/year = $20,000/year - Energy savings: $1,500-2,000/year from shifted consumption - Total: $21,500-22,000/year with minimal equipment cost

demand-response

Demand Response and Grid-Interactive Building Controls