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CNN Center. John Hester Turner Properties, Inc. CNN Center. Built in 1975 1,583,000 square feet on 18 floors Five structures joined by a common atrium Multiple building uses hotel, five cable networks, retail & food court, computer/data center, & office space
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CNN Center John Hester Turner Properties, Inc.
CNN Center • Built in 1975 • 1,583,000 square feet on 18 floors • Five structures joined by a common atrium • Multiple building uses • hotel, five cable networks, retail & food court, computer/data center, & office space • Building operated 7 days a week, 24 hours a day
CNN CenterPre-1994 Cooling Equipment • Main plant - three 1200 ton centrifugal chillers • with 0.9 kw/ton efficiency, R-500 refrigerant, installed in 1975 • Secondary plant - two 300 ton centrifugal chillers • cool the CNN Tower, 0.65 kW/ton efficiency, R-11 refrigerant, installed in 1986 • Five cooling towers installed in 1975 • Constant volume air distribution system • older areas (circa 1975) multi-zone units • newer areas (circa 1983) use VAV boxes
CNN CenterOriginal Building Envelope & Lighting • R-10 walls, with R-5 to R-10 roof • Mostly double-glazed, bronze tinted windows with aluminum frames • Primarily 40 Watt fluorescent light fixtures with T-12 lamps and electronic ballasts • Some incandescent down-light fixtures • Motion detectors added in 1993
HVAC systems being maintained and upgraded over time Expansion of facility decided on in late 1995 addition of two new networks and a new studio two of the original 1200 ton chillers replaced in 1994 with 1500 ton chillers need to replace third chiller & upgrade capacity CNN CenterProject Scenario
CNN CenterProject Challenges • Wanted operational flexibility • Wanted to capitalize on real-time pricing benefits • Needed emergency cooling & electrical generation • Building must be kept operational 24 hours a day throughout all retrofit work • Need to serve new network loads
CNN CenterSystem Solutions • Three new chillers, two electrical & one gas-engine driven • One new cooling tower added • Back-up electrical generator added • Chilled water piping balancing • Air handler units converted & upgraded to direct digital controls • Lighting load reductions made
CNN CenterNew Chiller Plant • Two York 1500 ton electrical centrifugal chillers • added in 1994, 0.6 kW/ton efficiency, R-22 refrigerant • One York/Caterpillar 1800 ton gas-engine-driven chiller • added in 1996, 2.03 COP, R-134a refrigerant • New cooling tower added for redundancy • Secondary chiller plant • now used as backup for CNN studios & data center • emergency electrical generators installed
CNN CenterChiller Piping • Constant volume primary piping system • small plant piped to more critical studio & network loads • dedicated chilled water pumps for each chiller • Unbalanced chiller loads discovered • flow test and analysis revealed piping wasn’t large enough for north part of building • increased pipe sizes saved having to run backup plant to meet loads
CNN CenterOther HVAC Improvements • Air handler units being upgraded • variable air volume diffusers • variable speed drive controls • Pneumatic controls being replaced with direct digital controls • Hotel hot water • future ability to preheat through plate heat exchanger with the gas-driven chiller’s jacket • new shell & tube heat exchanger for instantaneous hot water from building steam
CNN CenterLighting Improvements • T-12 lighting fixtures de-lamped from 4 to 2 lamps per fixture • Electronic ballasts added • Incandescent down-lights replaced with fluorescent PL fixtures • Motion sensors previously installed in offices
CNN CenterReal Time Pricing & Utility Competition • RTP rates are two-part tariffs • first part is standard bill based on the Customer Baseline Load (CBL) • second part charges the prevailing real-time price for energy use above the CBL • refund at real-time prices if under the CBL • CBL charges are usually higher than real-time prices • Gas chiller allows for a lower CBL • Competition led to cost savings on both electric and gas operation
CNN CenterIntegrated Economics • Cooling tower & lighting measure savings unknown • Lower payback measures help reduce overall payback
CNN CenterProject Results • Operational flexibility provided by the gas chiller • Reliable backup systems provided • Higher efficiencies of new chillers provides substantial savings • Loads being met thoughout existing building and expansion • Energy and utility bill savings