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 = a o + a 1 x + a 2 x 2

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

O&M Examples 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

Energy Management in Building (how to use BMS in EM?)

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 - 1 Chilled Water Supply Temperature Reset (CityPlaza) CHWST - summer 6.5°C ; winter 7.5 °C Reset CHWST in according to outdoor condition

Idea

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 vs Benefit Investment Modify control logic program in BMS Benefit Programmable predictable and verified Fully Automatic negligible additional investment & maintenance cost

Example 2 Free 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 vs Benefit Investment Motorized damper program in BMS Benefit Estimated saving HK$120,000/yr Negligible additional maintenance cost Fully automation

Example 3 Carpark 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

Implementation Strategy (Original & 1 st trail)

Implementation Strategy (2 nd & 3 rd trail)

Use of BMS Data collect & analysis - CO level Fan schedule programmed in BMS Output - Fan ON/OFF in high / low speed

Investment vs Benefit 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

Example 4 Optimal AHU/PAU Start Up Time in A/C System

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

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? Idea

Average Outdoor Temp at 08:00

AHU Control Strategy 23 0 C 07:25 07:00 07:50 Time 28 0 C 18 0 C Outdoor Temp.

PAU Control Strategy PAU (09:00) AHUs (07:00-07:50) Time ON OFF Outdoor Temp. > 18 0 C DB PAU/AHUs (07:50) Time ON OFF Outdoor Temp.  18 0 C DB

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 CO 2 emission for coal- fired power generation Fully automatic No O&M cost

Example 5 Optimal Static Pressure Reset in Variable Air Volume A/C System 2002 Hong Kong Eco-Business Awards Green Innovative Practice ‘Gold’ Award

Cityplaza Taikoo Shing Built in 1997 Grade A office with over 50000m 2 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 CO 2 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

Thank You!