CNN Center John Hester Turner Properties, Inc.

CNN Center Built in ,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 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 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 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 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