The Courtyard by Marriott has to supply hot water on demand to 119 rooms as well as a laundry facility and a small restaurant. Demand varies greatly depending on the number of guests and restaurant traffic, so the hotel needed a system to provide the flexibility of handling peak loads and off times.
Design engineer Scott Reed from Evansville Winnelson, the Navien distributor, designed a hot water supply system with seven Navien NPE-240 water heaters and three unheated tanks to circulate water to and from the Navien heaters. Joe Cox from Altstadt Plumbing worked with Scott to plan and install the system. The entire installation took less than two weeks.
Efficiency for high and low demand: Joe explained how they configured the water heating system. “You’ve got to consider how many rooms there are based on the fixtures and the amount of occupancy you can have at one time and then basing that on gallons per minute, get the size of the equipment needed to handle that load. But you don’t want equipment running constantly when it’s not needed. That’s where Navien becomes a benefit because in times of low use they can run minimally or not run at all. Then in highest demand periods, all seven Naviens kick in.”
Scott added, “We used unheated storage tanks to supply plenty of water to the Navien heaters. At any one point in time there’s 119 gallons times three which is close to 360 gallons that can be drawn out for heating.”
Easier venting installation: “On this installation we used schedule 40 PVC solid core for intake and CPVC schedule 80 for exhaust,” Joe said.
Durability: Joe likes the long-term reliability of the NPE unit. “With the two stainless steel heat exchangers you don’t have to worry about scaling and corrosion so much. And basically the warranties are great.”
The Courtyard by Marriott in Evansville, Indiana, uses seven Navien NPE-240’s to provide a steady supply of hot water for high and low demand.