Wireless Sensing and Control of the Indoor Environment in Buildings

Objective:Develop techniques to improve building operation through intensive wireless sensing and information technology

Opportunities Reduce energy use Increase energy demand responsiveness Improve comfort and productivity Improve synergy among systems and occupants

Collaboration: Center for the Built Environment CITRIS, BSAC, BWRC, Intel Lab

Buildings and Energy

Buildings use more than 1/3 of total energy:

(Heating, Ventilating, Air Conditioning, Lighting, Equipment)

Roughly half of this in Commercial Buildings, half Residential.

Roughly half is wasted in each.

In offices, HVAC leads the list of occupant complaint topics.

Improvements will come from designs that integrate the building, its mechanical/electrical systems, and its occupants.

Integration depends on improved information about how the building is operating (more sensors, more smarts)

What to do?

1) Sense more, where it counts

Wireless networks of long-lived sensors

Mobile, cheap (~$800/wired sensor)

Fit them in ceiling tiles, furnishings, etc.

2) Include the occupants

Information

Insight

Influence

Interfaces

Input Information Models OutputWeather:

Current

Day’s Forecast

Energy Price:

Current

Hourly forecast

Building’s current energy use and cost

Messages, Alerts:

Utility, Bldg Mg’t.

Occupant input

Building energy use (simulated hourly loads and HVAC system use)

Comfort level

Cost (hourly; energy use x price)

Building control algorithms

Advice Messages

Interactive interfaces show hourly profiles of cost/comfort/energy as a consequence of occupant’s choices.

Occupant actuation of building and equipment

Automatic actuation of building systems

Diagnosis of building performance problems

Sensors

Now: Maximum of 1 thermostat /room for HVAC

(now $800 per installed wired sensor!)

Available

(but rare):

Light sensors for dimming lights.Occupancy sensors combined with light sensors for lighting control.CO2-based ventilation controllers

Possible: Many!

Current Projects

Multi-sensor/single actuator control of temperature

What is the benefit of just adding more sensors, as in a retrofit?

(see poster)

Control of Stratified Systems

Using sensors to manage temperature gradients in underfloor air systems.

By optimizing efficiency, encourage adoption of this new technology.

Air velocity measurement

Benefits indoor air quality, energy, and comfort

Interface between system and occupantsWeb-based, 1st for diagnosing building operations

Control of UFAD Systems

Conventional Overhead SystemUnderfoor Air Distribution

Underfloor Air Supply

(See Poster): sensors arrayed vertically improve energy performance

Task-Ambient Conditioning

Test of Desk Supply Device

Maximum whole-body cooling rate: 3-4°C (5-7°F).

Similar ΔT possible between adjacent workstations.

Mixed-mode Buildings

Improved occupant comfort/satisfaction Potential for greatly reduced energy But: can waste energy unless monitored and controlled A perfect application for CITRIS smart sensor control

A hybrid approach to space conditioning that combines natural ventilation with

mechanical ventilation and cooling.

Mixed-mode Design

Sophisticated building envelopes and structures

Integration of window systems with HVAC systems

Integrating automatic and occupant control of indoor environment

New systems needed for sensing building conditions and informing occupants

Demo opportunity next year

CBE Web-based User Interface Objective

Better energy and maintenance performance

Issues Occupants are virtual sensors and actuators Integration of sensor information with occupant information

Collaboration GSA; prototype

in San Franciscothis year

EnergyManagement

System

MaintenanceDatabase

Occupants

BuildingEngineers

Server

User Interface;

Air Velocity Measurement

Applications

Heat transfer in rooms and ducts

Ventilation rate, air quality

Perception of comfort, or draft

Benefit: enables mixed-mode building design

Picoradio Testbed

Future Projects (1)

New Sensors

Occupancy (IR and acoustic motion detection)

Surface temperatures (via longwave IR)

CO2 (proxy for occupancy and air quality)

Light (illuminance and luminance)

Noise

Door & window switches

Plug-sized wattmeters for appliances and office equipment

Future Projects (2) Applications

Control of perimeter zones in buildings: Thermal control strategies Shading device control strategies Optimal sensor configurations Inclusion of the occupant in the control loop Interconnection with lighting controls Other interactions: noise masking, fire, security.. Economic analysis of wireless-enabled systems

Residential Night ventilation control

Future Projects (3)

Information systems for building occupants and operators:

Periodic evaluation of building performance

PDA-sized information displays

Forecasts of climate, energy prices, and building operational choices

Forecasts of consequences of choices offered to occupants

And last, the SABER Center proposal

Sensors And Building Engineering Research Center

Preproposal for an NSF Engineering Research Center.

PI: Paul Wright. Large interdisciplinary team.

Karma excellent.

If successful, final proposal will be due in November.