Controlling Sutardja Dai Hall Andrew Krioukov Stephen Dawson-Haggerty, Jay Taneja David Culler

Buildings 40% of US electricity 42% of greenhouse gas footprint Want: – Energy Efficiency – Flexible Load

Building Power Consumption 11% 1MW 883 kW

Sutardja Dai Hall 3 years old 7 floors, 140k sq. feet Collaboratories, offices, classrooms, auditorium & nanofab Siemens Controls, WattStopper > 6000 sensors & actuators

Building Control Network Sensors, Actuators Controllers WattStopper Server Modem Internet sMAP/ HTTP Readings & Actuation BACnet/IP Gateway Modem Siemens P2 over RS-485 Siemens Server

Cooling Tower Chiller Economizer Air Handler Hot Water VAV

Problems 1. Oblivious control loops – Increasing thermostat on warm day wastes energy – Conflicting controls 2. Oversizing – Excess ventilation – Oversized chiller Inefficient, Inflexible Control

Why? Modular Building Controller Motorola MHz Processor 3MB RAM K bps 60 day battery backup Hardware: – Resource limited – Reliability is the goal – Supports independent operation Generic control logic: Oversizing ensures comfortable operation in most buildings with less effort Historic: Replacing pneumatic/analog controls

Goal Globally-aware control with the same reliability. What is the architecture? – How to ensure: robustness, security and safety? What is the control policy?

Building Control Architecture Internet Weather, Energy Prices Low-level Control Sensors & Actuators High-level Control Set points, PID parameters Valve pos, Damper pos, Fan speed Building- wide optimization PID Loops How to do “atomic” building configuration changes? Security model? Enforcing safety constraints.

Policy Components Supply air temp Airflow Room set points Cold water pumps Chiller Hot water pumps

Variable Air Volume (VAV) Box Ventilation Maintain temperature 100% 0% Cold Airflow Heating Valve Setpoint Too Hot Too Cold Min airflow

VAV Control 100% Cooling 100% Heating Dead band

Conflicting VAVs Max Cooling S1-1 – Boiler room S4-4 – Floor 4 open office S5-8 - Floor 5 office S Floor 5 open office S Floor 7 open office S Floor 7 open office S7-1 - Floor 7 open office Max heating S1-9 - Mechanical Room S Floor 4 open office S5-9 - Floor 5 hallway S Floor 5 open office S5-4 - Floor 5 open office S7-9 - Floor 7 open office S7-3 - Floor 7 open office

Ventilation TITLE 24: – 15 CFM per person of fresh air – 900 – 1100 PPM CO 2 VAVs have static minimum airflow base on: – Maximum occupancy – Minimum fresh air intake

Fresh Air Intake

Questions?