Big lineup: 29 A. O. Smith tankless units keep hotel guests in hot water

September 15, 2016

Cleveland’s newest Holiday Inn may look like a typical hotel from the outside, but its location, purpose, and special features make it one of a kind. The hotel is built adjacent to the world renowned Cleveland Clinic and is designed to serve the many people who visit or serve the sprawling clinic campus. Looking inside the hotel, visitors will find another unique feature: a mechanical room equipped with 29 wall-mounted A. O. Smith ATI 540H-N fully modulating condensing tankless water heaters.

“We’ve done a number of tankless installations in Ohio, but never anything of this scope,” Kevin Conyngham of LIBB Company, Inc., the manufacturer’s representative responsible for coordinating the project, observed.
The owners of the hotel, which opened in May, wanted to use tankless water heaters because of the Cleveland Clinic’s interest in energy efficiency and sustainability, Conyngham explained. The 199,000 BTU A. O. Smith units deliver an energy factor of 0.95 and, working together, provide more than enough hot water for the guests and staff of the hotel.

Unlike many hotels, the new Holiday Inn-Cleveland Clinic will not experience the same type of 6:00 to 8:00 a.m. morning “rush hours” during which guests demand significant quantities of hot water for showers or bathing. Suppliers to the nearby clinic, visiting physicians, and family members of patients will make up the bulk of the hotel’s guests—they tend to arrive and depart at all hours of the day or night. Nonetheless, the A. O. Smith units are ready to meet their hot water needs throughout the day.

The 29 units are divided into two zones, Jim Roddy Jr., president of Northern Ohio Plumbing Co., Inc., the mechanical contractor who installed the water heaters, explained. Eleven units supply 140-degree hot water to the laundry and kitchen, while 18 units serve the 284 guest rooms with 110-degree hot water. Not surprisingly, the laundry requires the most hot water, although the Moce Café and Bar and the hotel’s event facilities also demand ample quantities of hot water. The A. O. Smith tankless water heaters’ modulating capability means the units will be able to ramp up to meet peak demands while, at the same time, saving energy and cost for the owner group.

The NOP team identified a number of creative approaches that saved space and reduced cost during the installation. The original specification called for a installing the tankless units on a pre-fabricated rack system in the mechanical room. Instead of using the rack system approach, Ben Welton of NOP came up with a unique wall-mounted installation that saved mechanical room floor space. He staggered the units make the most of the available walls; the staggered method also better accommodated the water heaters’ piping and venting.

“The finished job is nothing like the original drawings,” Conyngham noted.

NOP also maximized the venting capabilities of the tankless units. The contractor installed one large plenum that branched into individual air intake pipes to supply the 29 water heaters with fresh air. This approach required creating just one hole in the mechanical room’s exterior wall. The units’ exhaust vents are collected into a set of four large exhaust vents that exit the building through one wall. PVC water lines from each of the tankless water heaters lead to a series of risers; one pair of risers serves each guest floor.

The modulating capability of the A. O. Smith condensing tankless water heaters eliminated the need for the hot water storage tank normally found in a hotel application. NOP tested the system, running multiple showers on multiple floors at the same time, Roddy pointed out. The water heaters were able to keep up with the demand.

The A. O. Smith 199,000 BTU tankless units are rated to deliver a maximum flow rate of 10 gallons of hot water per minute. Even in the dead of Cleveland’s cold winters, the water heaters can deliver a minimum of four gallons of hot water per minute or seven gallons of blended water, Conyngham pointed out.

The water heaters themselves and the layout of the mechanical room promise to make maintenance a snap.

“The nice part is the redundancy of the system. If one unit requires maintenance, you don’t have to shut down the system, and the hotel will still have hot water,” Welton noted.