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Energy Management with the use of an Intelligent Building Management System. Focus. Basic Concept of Intelligent Building Management System How an intelligent BMS can be applied on Energy Management in large size commercial buildings. Basic Concept of Intelligent Building Management System.
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Energy Management with the use of an Intelligent Building Management System
Focus • Basic Concept of Intelligent Building Management System • How an intelligent BMS can be applied on Energy Management in large size commercial buildings
Basic Concept of Intelligent Building Management System • What is BMS? (computer?) • Instruments • PC + software • Network • Controller
Building Management System(Past, Present, Future) • Recorder • Information Technology System (ITS) • data monitoring, implementation & transfer • Artificial Intelligent System (ATS) • self-learning, diagnosis
What is the duties of BMS ? • Reporting - information print out • Monitoring - provide message / signal /alarm • Prediction - cooling demand, energy • Control - program, schedule • Diagnosis - analysis
Information Flow in BMS • signal • data • graphic • models • program • Y = mx + c • y = ao + a1x + a2x2
Advantages in using BMS in Building Facilities Management • Operation • Centralize , Program, Automate, Remote • flexible, save operation & maintenance cost • Maintenance • reactive proactive (monitor, keep checking) • increase services quality level (SQL) • Applicable to Energy Management
Operation ON/OFF equipment by IR-sensor Signal - occupants zoning & scheduling by BMS program ON/OFF/reset output Automation Maintenance Fault identification of VAV boxes Signal - damper position, temperature abnormal data presented in BMS Output - message Manpower saving O&M Examples
What is Energy Management Energy Audit Data Analysis Identify Energy Saving Opportunities Implementation Measurement & verification (M&V) Evaluation
Energy Management & BMS • Energy audit • Data Analysis • Identify saving • Implementation • M&V • Evaluation
Example - 1Chilled Water Supply Temperature Reset (CityPlaza) • CHWST - summer 6.5°C ; winter 7.5 °C • Reset CHWST in according to outdoor condition
Use of BMS • Data collect & analysis - outdoor temperature, chiller performance, CHW supply & return temperature • Algorithm programmed in BMS • Output - CHW supply temperature reset value • Verify the energy saving from data recorded in BMS
Investment Modify control logic program in BMS Benefit Programmable predictable and verified Fully Automatic negligible additional investment & maintenance cost Investment vs Benefit
Example 2Free Cooling by Outdoor Air (Taikoo Place) • Constant amount of outdoor air intake • Amount of outdoor air intake in according to the air temperature between outdoor & indoor
Idea • Air temperature outdoor < indoor extra cooling capacity • More Outdoor Air & Less Return Air • Cooler intake air before cooling coil less cooling demand
Control Strategy • Air temperature Outdoor < Indoor • Adjusting the dampers position of outdoor air and return air
Investment Motorized damper program in BMS Benefit Estimated saving HK$120,000/yr Negligible additional maintenance cost Fully automation Investment vs Benefit
Example 3Carpark Ventilation Control Based on Actual CO level (CityPlaza) • Any air quality problem? • Fans are operated in 2 speed • High speed 7:00 – 23:00 • Low speed 23:00 – tomorrow 7:00
Idea • Installation of CO monitoring system • BMS used to trend the CO conc. profile • EPD requirement vs actual CO conc. (gap) • Possibility to reduce fan speed
Use of BMS • Data collect & analysis - CO level • Fan schedule programmed in BMS • Output - Fan ON/OFF in high / low speed
Investment Initial cost is HK$560,000 Maintenance cost is HK$42,000/yr Benefit Estimated annual saving is HK$970,000 Automation Health & Acceptable IAQ level Investment vs Benefit
Background • Office Tower A/C hour 08:00-19:00 • AHUs start at 07:00 / 07:30 for pre-cooling • PAUs start with AHU • BMS to control the A/C system
Idea • PAU (Fresh Air) • Office hours usually start at 09:00 • Delay the PAU starting time? • AHU (Cooling) • Office space temp. vary with outdoor temp. • Desire the optimum start up time of AHU to just meet the cool down period?
Outdoor Temp. 280C 230C 180C Time 07:00 07:25 07:50 AHU Control Strategy
Outdoor Temp. > 18 0C DB Outdoor Temp. 18 0C DB ON ON OFF Time OFF Time PAU (09:00) AHUs (07:00-07:50) PAU/AHUs (07:50) PAU Control Strategy
Use of BMS • Feedback signal • outdoor temperature • Programming in BMS • Output - AHU/PAU start up time
Investment • Hardware - None • Software • BMS contractor to write a program to incorporate into the PAU/AHU control • Initial cost - HK$11,600.00
Benefit • Yearly saving about HK$160,000 • equivalent to 96,000kg CO2 emission for coal-fired power generation • Fully automatic • No O&M cost
Example 5Optimal Static Pressure Reset in Variable Air Volume A/C System 2002 Hong Kong Eco-Business Awards Green Innovative Practice ‘Gold’ Award
CityplazaTaikoo Shing • Built in 1997 • Grade A office with over 50000m2 • HK BEAM -Excellent rating
Schematic Diagram of VAV System P - Pressure sensor , D - Control Damper, VSD - Variable speed Drive
Use of BMS • Feedback signal • 32 nos VAV damper position • Programming in BMS • Output - main duct pressure
Static Pressure Profile Light Load AHU On
Investment • Hardware • added a control unit • Software • BMS contractor to write a program according to designed control logic • Initial cost - HK$69,400.00
Benefit • Yearly saving is about HK$200,000 • equivalent to 120,000kg CO2 emission for coal-fired power generation • VAV boxes re-commissioned • noise reduced at part load • assist in VAV fault diagnosis • Fully automatic
Future Development • Fruitful quality of information • Web base performance • Self learning • fault detection and diagnostic