CNN Center John Hester Turner Properties Inc CNN

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 Center Pre-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 k. W/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 Center Original 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

CNN Center Project Scenario • 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 Center Project 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 Center System 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 Center New Chiller Plant • Two York 1500 ton electrical centrifugal chillers – added in 1994, 0. 6 k. W/ton efficiency, R-22 refrigerant • One York/Caterpillar 1800 ton gas-engine-driven chiller – added in 1996, 2. 03 COP, R-134 a refrigerant • New cooling tower added for redundancy • Secondary chiller plant – now used as backup for CNN studios & data center – emergency electrical generators installed

CNN Center Chiller 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 Center Other 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 Center Lighting 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 Center Real 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 Center Electric Energy Use Comparison

CNN Center Integrated Economics • Cooling tower & lighting measure savings unknown • Lower payback measures help reduce overall payback

CNN Center Project 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