San Jose, California…The San Jose
Mercury News' 30 year old headquarters building located at 750 Ridder Park Drive in San Jose, California was in dire need of a major HVAC renovation. The large Northern California regional newspaper which operated 24 hours a day, needed a cost effective way to renovate the building without disrupting its daily operations. The goal of the renovation was to convert the existing constant air volume systems to variable air volume systems with DDC controls.
Unique HVAC Design Solution
Warren Technology worked with York International and Therma Inc., one of the largest Design/ Build contractors in the country to provide a cost effective, state-of-the-art comfort control system that met both the needs of management and its employees. Over 290 of Warren's Leopard intellivent® variable air volume diffusers were used in conjunction with a York DDC energy management system to provide substantial energy savings, improved comfort and indoor air quality at the newspaper.
Employee Complaints Mount
According to Facility Manager Jim Thurman, the headquarters building which included over 465,000 square feet of space and housed over 1,500 employees, was costly to operate and employee comfort complaints were on the rise. Complaints that employees made to him on a daily basis included, “being too hot," “being too cold" or “being uncomfortable because cold air was blowing down directly on them."
A Costly Alternative
The original system that was designed and bid for the renovation was a typical VAV system with hot water reheat, DDC controls, conversion of the air handlers to VAV, new controls and new ducting. In order to replace certain ductwork and to install the almost 300 VAV terminal units, it would have required removing and replacing countless ceiling tiles, restringing cable, adjusting lighting fixtures, and installing over 5,000 feet of new hot water piping.
This system design was not feasible because the newspaper operated 24 hours a day. Employees could not be moved to another location within the building or to another building. The installation of a typical VAV system would have had a significant impact on the working environment and productivity of the employees. Management at San Jose Mercury News needed a cost effective solution.
Terry Kearny of Mechanical Engineered Services, local representative for Warren Technology, John Karamanos, Senior Sales Engineer, York International and Ralph Dorotinsky, Vice President Therma Inc., teamed up to propose a state-of-the-art system design utilizing Warren's Leopard Intellivent® personal VAV diffusers.
Jerry Polk, V.P. of Operations and Engineering Manager Larry Bonanti evaluated the alternate design/build proposal along with a number of other designs. After an intense evaluation, it was decided to go ahead with the Warren-Therma-York project. The estimated cost savings over the original base bid system was more than $450,000.
The project covered over 140,000 square feet of office space and was completed at a cost of under $700,000. As a result of the energy savings achieved versus the previous constant volume system, the company received a $50,000 rebate from Pacific Gas & Electric.
Putting It All Together
The system design included 291 Leopard Intellivents®, 14 air handlers, 28 variable frequency drives, 15 reheat zones, hot water boiler and pump control, compressor monitoring, reengineering of the economizer, duct testing and balancing and a complete York DDC package.
All 291 of the Leopard Intellivent® slave models were fitted with quick connects which enabled the variable air volume diffusers to receive signals from the York DDC controllers. In response to a signal from the controller, the Intellivents® built-in VAV mechanism modulates to a more open or closed position to precisely meet the individual temperature requirements in each room.
A Novel Idea Does The Trick
One major problem that presented itself was how to effectively install the wiring between each Intellivent® diffuser and subcontroller without disrupting the employees who were working. Mr. Karamanos and Mr. Dorotinsky borrowed an idea from their medieval ancestors; a crossbow was used to shoot the wiring over the top of the ceiling tiles. An ingenious solution that reduced the installation time dramatically.
Quick Installation Keeps Presses Running
The modular design of the Leopard Intellivents® enabled the retrofit to proceed quickly with minimal disruption to occupants working diligently to meet demanding deadlines. The billion dollar newspaper was always delivered right on time.
Improved VAV Performance
Leopard Intellivent® VAV diffusers provide a distinct advantage over existing VAV system designs. When airflow is reduced in traditional VAV systems, conventional diffusers fail to maintain sufficient outlet velocities, resulting in cold air downdrafts and dumping into the occupied space.
Due to its patented high velocity dimple-jets and VAV device, the Leopard Intellivent® maintains a high discharge velocity even during reduced airflow to maintain optimal room air circulation. Patented dimple-jets direct airflow parallel to the ceiling to eliminate downdrafts and stagnant air pockets.
Future Design Flexibility
Constructed of lightweight aluminum, Leopard Intellivent® personal diffusers are easily installed in existing office buildings without replacing ductwork, dismantling ceiling, or disturbing tenants. Intellivents® can also be easily relocated as office layouts change. Standard Leopard Intellivent® models are available with a built-in thermostat to provide individual room temperature control.
Eric Lattona, Facilities Supervisor stated, “You could feel a difference in the way air was circulating right after the first phase was completed." He said several employees made comments to him on how much more comfortable they were after the Intellivents® were installed.
Facility Manager Jim Thurman was extremely pleased with the outcome and dramatic reduction in employee comfort complaints. “The new system is operating 300% better than the old constant air volume system it replaced," Jim said. “We have several other reconstruction projects in the works and I can see the Leopard Intellivents® playing a key role on all future HVAC renovations."