Project Goals:
- Replace old gas-fired boiler and 500-gallon storage tank supplying DHW
- Achieve sufficient DHW to meet demand in 99-room hotel
- Provide DHW for laundry, meeting spaces, kitchen areas
- Minimal disruption to guests
The owners of the Best Western Plus New Englander Hotel located in Woburn, Mass., a suburb located about 10 miles north of Boston, decided to replace an old gas-fired boiler and tank serving its 99-room hotel equipped with two commercial washing machines after the existing 500-gallon tank began leaking.
Heneghan and Sons Plumbing and Heating in Pepperell, Mass. quoted a system of 10-intelligent cascaded Bosch Greentherm C1050ES gas-fired condensing tankless water heaters, delivering up to 107 gallons of hot water per minute. The Bosch units were priced less than a competitive unit, and offer a superior warranty.
Heneghan Plumbing, with materials provided by PV Sullivan (Quincy, Mass.) was able to keep the existing hot water system running while installing the new system, and Colin added that “the changeover was a lot easier than we ever expected. We found the Bosch units easy to install, program and troubleshoot. It was made simpler with support from Bosch Sales Representative Dan McDermott and Craig Porter from Bosch technical support.”
Intelligent Cascading
A cascading application may be considered if the potential hot water demand exceeds the capacity of one gas tankless water heater. The cascading set up supports variable flow inputs and is designed for large homes and commercial applications. Use of the Intelligent Cascading Kit, unlike other parallel applications, maintains the activation flow rate of a single appliance.
Intelligent Cascading allows up to twenty four appliances to be connected in parallel to achieve flow rates up to 257 gallons per minute for Bosch Greentherm 1050ES (see figure). One of the appliances will serve as the controlling primary appliance and will attempt to meet the hot water demand. If the hot water demand is beyond the capacity of the primary appliance, a signal is sent to one or more of the secondary appliances to ignite. With the Intelligent Cascading, after each 100 hours of operation, the system will automatically rotate which heater serves as the primary; thus the primary control appliance is rotated throughout the cascade setup to distribute the load of each unit. One of the appliances serves as the primary control and attempts to meet the hot water demand. If the hot water demand is beyond the capacity of the primary appliance, a signal is sent to one or more of the secondary appliances to ignite.
Note: Refer to Bosch Greentherm Tankless Water Heaters Applications Guide at this link http://www.bosch-climate.us/support-center/download-center/downloads/bosch-manuals/bosch-tankless-manuals.html
The 10-unit Bosch Greentherm cascade installed in the Best Western Hotel delivers high efficiency hot water delivering up to 107 gallons per minute. This satisfies demand from guest rooms, meeting space, laundry, and kitchen areas throughout the busy hotel. The hotel owner reported fuel savings of approximately $1,500 to $2,000 per month in the first six months of operation. Compared with a competitive tankless installation at a similar hotel with same number of rooms, this Bosch installation saved about $500 more per month.
Project Summary:
Best Western Hotel, Woburn Massachusetts
Equipment: Bosch Greentherm C1050ES natural gas fired condensing tankless water heaters in 10-unit cascade
Installing Contractor: Heneghan & Sons Plumbing &Heating, Pepperell, MA
Wholesale Supplier: P.V. Sullivan, Quincy, MA
Project Completion: 2014
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