3 6 O c t o b e r 2 0 0 2 BACnet ® Today | A Supp lemen t t o ASHRAE Jou rna l

hen the Shanghai Muncipal Government set out to build the larg-est scientific and technical museum in Asia, it didn’t focus only on

the exhibits inside the building. It wanted the building itself to be ashowcase for state-of-the-art building systems. It selected BACnet asthe building automation protocol.

WBy Steve Tom, P.E., Member ASHRAE

Shanghai Technology Museum

Covering 17 acres (7 ha) in Shanghai’sPudong financial district, the Scienceand Technology museum was designedto serve as a major social and culturalcenter. Built at a cost of $180 millionU.S., the museum encompasses more than1 million ft2 (96 500 m2) of floor space. Astriking feature architecturally, the mu-seum is built in a semi-circular shape thatrises from one story to five stories, fromwest to east.

Inside, exhibits include a miniaturehydroelectric plant, a 7,500 ft2 (697 m2)rain forest, a CAD/CAM center wherevisitors can design and build small ob-

jects, and a children’s exhibit calledTechnoland. It also includes an aviary,

an aquarium, two IMAX theaters, and anearthquake center — complete with amoving earthquake platform and videodisplays that allow visitors to experiencea simulated earthquake.

A facility of this magnitude presents asignificant challenge from an HVACstandpoint. A Beijing and an Americancontrols firm worked together to designa Web-based BACnet control system witha bilingual user interface. The systemincluded more than 3,200 BACnet con-trol points. An additional 1,000 pointsin non-BACnet equipment were moni-tored by the BACnet system.

Control networks included a 10 MbpsBACnet/IP Ethernet backbone, 156 KbpsBACnet over ARCNET subnets, 38.4 and9.6 Kbps BACnet over MS/TP subnets,and proprietary networks tied into theBACnet system through gateway (trans-lator) modules.

The U.S. firm supplied much of the con-trol hardware, but as shown in Figure 1,

President Jiang Zemin of China with U.S. Presi-dent George W. Bush at the Shanghai Scienceand Technology Museum in October 2001.

The Shanghai Science and Technology Museum plans displays of its BACnet system so that visitors can see how it works.

The following article was published in ASHRAE Journal, October 2002. © Copyright 2002 American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. It is presented for educational purposes only. This article may not be copied and/or distributed electronically or inpaper form without permission of ASHRAE.

BACnet ® Today | A Supp lemen t t o ASHRAE Jou rna l O c t o b e r 2 0 0 2 37

‘The museum is dedicated to the

harmony of Nature, Man, and Tech-

nology and contains five major

exhibition halls addressing the top-

ics of Heaven and Earth, Life, Wis-

dom, Creativity, and the Future.’

For example, the AHUs depend upon chilled water providedby a central chiller and ice-storage system. The AHUs responddirectly to changes in the cooling load by opening or closingchilled water control valves. The position of this valve is com-municated to the chiller system through the BACnet network,alerting the chillers to the change in the building load and al-lowing them to respond accordingly.

Multiple variable frequency drive control panels controlledthe chilled water and hot water loop pumps (Figure 3). Thesepanels were networked together with a 9600 bps BACnet MS/TP network. Since the panels were already using BACnet, it wasa simple matter to connect them to the BACnet/IP backbone andmake the temperatures, pressures, start/stop controls, alarms, etc.,available to the building automation system.

Several of the building subsystems used proprietary con-trol protocols, including the chillers, ice storage system, firealarms, and building security system. The chiller and ice stor-age system used a network of program loop controllers (PLC)that was integrated into the BACnet system through a gateway(Figure 4). This allowed the central automation system to moni-

tor and adjust temperatures, setpoints,pump status, etc., from approximately300 points. Additionally, once thedata was brought into the gateway, itwas linked to BACnet trends, alarms,and schedules, which were also ac-cessed by the central system.

The fire and life-safety system wassimilarly linked to the central systemthrough a gateway. This made ap-proximately 200 data points avail-able to BACnet, including the statusof pull stations, smoke detectors, andfire suppression pumps. The gatewaymodule made this information avail-

many other vendors were involved in the total project. BACnetprovided the common protocol for these systems.

Native BACnet controllers were used in the air-handlingunits (AHUs), boilers, heat exchangers, and lighting systems.With more than 100 air-handling units, 350 separate lightingcircuits, 300 fans, seven heat recovery wheels, five heat ex-changers, and three boilers, this was a sizable project in itself.The air-handling system consisted of multiple constant vol-ume single-zone AHUs and a large, variable air volume venti-lation fan. Ventilation flow rates vary throughout the day basedupon an adjustable schedule. Several different arrangementsof single zone AHUs were used, depending upon the require-ments of the zone. Figure 2 shows a typical arrangement.

The lighting system consists of individual controllers for zoneand room lighting. Lighting levels are controlled based uponadjustable schedules, with local override switches for unsched-uled occupancy. BACnet objects and services are used through-out, including BACnet schedules, alarms and trends. BACnetnetwork services (Read Property and Write Property) were usedextensively to coordinate the operation of this equipment.

Figure 1: Schematic summary of building controls for Shanghai museum.

HTML Page

Power Monitoring

Automated Logic Controlled Equip-ment (AHUs, Boilers, Heat Exchang-ers and Lights)

ITT Bell & Gossett VFD Pump Control

Proprietary ControlSystems (Chiller, Ice Stor-age, Fire and Security) Automated Logic Monitor-

ing of Elevators, Water andWastewater Systems

Web Browser Web Browser

WebCTRLServer 10 Mbps Ethernet

BACnetRouter

BACnetRouter BACnet

Router

BACnetController

BACnetRouter

BACnetController

ARCNET156Kbps

ARCNET156Kbps

BACnetControllerMS/TP

9.6 Kbps

BACnetController

Gateway

ProprietaryController

ProprietaryNetwork

MS/TP38.4Kbps

Hardwireto Equipment

Figure 2: Typical air-handling unit. The museum has more than 100 air-handling units.

able to the central system, generated BACnet alarms as appro-priate, and controlled safety interlocks with other BACnetequipment such as fans and AHUs.

A third type of interface was used to connect to the eleva-tors, domestic water, and wastewater systems. These systemsdid not use networked controls but instead were controlled byconventional electric and electronic packaged controls. Forthese systems, BACnet control modules were hardwired tomonitoring points in the conventional control systems. Thismade the status of these systems avail-able to the building automation sys-tem, and also allowed the controllersto generate BACnet trends and alarmsbased on the data read from the points.

One non-BACnet interface wasused with the building automationsystem. A power monitoring stationcame with a built-in Web page inter-face. Since the BAS also used a Webinterface, it was a simple matter tointegrate the power system screensinto the building automation system.However, a limitation to this inter-face is that it does not provide a ma-chine-friendly interface to thebuilding control system. The HTMLdata provided by the power monitoring station is designed to“draw” Web pages, which are viewed by the system operator.This operator can then use the BACnet control system to turnequipment on and off and adjust setpoints as required tooptimize power use. The HTML data is, therefore, easily inte-

Figure 3: Variable speed pumps are controlled by variable frequencydrive control panels.

Figure 5: The cover graphic for the lighting system. As with many othergraphics in this project, it highlights the fact that BACnet is in control.

grated into the Web-based front end, but it does not provideautomated control.

Two major milestones occurred in the construction program.The first was to complete the meeting halls and conferencefacilities needed to host the Asia-Pacific Economic Coopera-

tion (APEC) Summit in October2001. The second was to completethe exhibition halls and open themuseum to the public. The f irstphase was completed on scheduleand the leaders of 21 Pacific Rimnations met in the museum’s newconference center. Following theAPEC Summit, construction focusedon the museum itself and this openedto the public in December 2001. Aswith any museum of this stature, con-struction is never really finished, andnew exhibits and facilities are al-ready in the works. Among these is aplan to add kiosks where the build-ing automation system will be on

display, and visitors will be able to navigate through the sys-tem and see BACnet in action (Figure 5).

Steve Tom, P.E., is director of technical information withAutomated Logic in Kennesaw, Ga.

Figure 4: BACnet interface to third-party equipment.

3 8 O c t o b e r 2 0 0 2 BACnet ® Today | A Supp lemen t t o ASHRAE Jou rna l