Big Savings Adapting to Actual-Time Usage
BOC grad Noreen McKinley is the chief engineer at the Marriott Santa Clara in California. With energy savings now recognized as very high on a budget priority list, the hotel’s ownership wanted to implement some energy-saving measures. With two restaurants, room service and meeting room services, one of the areas under scrutiny was the kitchens.
Kitchen fan hoods did not run 24/7, but were on a timer that was scheduled to run during main business hours of 4 a.m. to 11 p.m. Daily occupancy is varied and business volume for the Marriott Santa Clara can be anywhere from 40% – 100%. Running on a timer was not an adequate solution. Targeting the kitchen hoods, the decision was to hone in on retrofitting the hotel’s eleven kitchen hoods by installing variable frequency drives (VFD) with Intelli-hood keypads and hood-mounted optic sensors that would determine the exhaust air flow based on need.
Operating is simple. A keypad is used to turn on the fans and “its processor sends a speed reference signal to the VFD. Now the hoods think for themselves and only run as needed, based on temperature and smoke from cooking,” states McKinley. “If there are only a few smaller meetings, the need for food service is minimal. Fan speed adjusts automatically and run times are reduced, so less energy is used. The same goes for the restaurants.”
Energy cost savings potential for the hotel are excellent. Annual utility costs for the fan hood operation before energy projects were implemented were estimated to be $108,842. Savings were calculated based on operating hours, estimated cooking loads, comparable utility rates and local climate data and estimated to be $43,857 per year – a 40.3% decrease in electrical usage, between the fan, heating and cooling savings. Net installed cost for all eleven retrofits, which included a utility rebate of $13,125 from Silicon Valley Power, was $66,153, which would mean a payback of 1.5 years. Environmental savings are estimated to be 189,904 pounds of CO2 per year.
The Marriott Santa Clara has implemented several energy-saving projects, including installation of digital guest room energy controls, HVAC retrofits to energy conservation units, and retro-commissioning projects on lighting (retrofits) and EMS controls. With 795 rooms and at 474,629 square feet, 23.500 of which is meeting room space, the savings measures really add up.
Marriott has several BOC graduates in its ranks and when McKinley received information on the classes a few years ago, she decided to take the series. “I found it to be one of the most knowledgeable learning experiences I have had in a classroom setting. At that time, I had decided to send my department and they all could not say enough about the classes,” she says.