The clock was ticking in more ways than one for the Holiday Inn in Downtown Knoxville, Tennessee this past August.
With only weeks to go before the first 2012 home game between the University of Tennessee and Georgia State, the hotel was in the midst of a complete domestic hot water retrofit. Anticipating a full house for the game, the owner made it clear that the system had to be up and running in time for the onslaught of football fans. Furthermore, installations had to take place quickly and seamlessly, so that hotel guests would not be without hot water for more than a few hours.
The replacement was long overdue. For decades the hotel had relied on three electric hot water tank heaters, each operating independently due to three distinctly different pressure requirements at the hotel. The owner was eager to switch to more efficient gas-fired appliances and put an end to recurrent part replacement and repairs to the existing heaters. He began working with Jarett Morgan of Ferguson Enterprises to make it happen.
Jarett had just begun to work with Lochinvar for high efficiency water heaters and Boilers – particularly their condensing boiler line. He felt confident about the product and the manufacturer, as well as the service he had received from JMP, the Lochinvar rep in the area. It was a fortuitous connection since JMP also reps Hyfab prefabricated pumping systems. Jarett recommended both to the Holiday Inn owner.
According to Jarett by incorporating the Lochinvar condensing water heaters, pumps and other equipment all onto one prefabricated hot water system, the Holiday Inn shaved several weeks off of their installation time, and quite a bit of cost.
“Everything came in already plumbed, except for the water connections. This took a lot of the burden of planning off the part of the owner. And when the package arrived, we knew that everything was installed according to manufacturing specifications,” said Jarett.
Onboard Variable Speed Recirculation System
The Holiday Inn Hyfab package was unique in several ways. First, it was designed so that it could be shipped in sections and then re-assembled at the job site. The skid supporting four Lochinvar Armor condensing water heaters, B&G pumps, and controls was built in two separate sections. Three 752 gallon Lochinvar hot water storage tanks were shipped separately and joined to the package components onsite. The skid sections fit easily through the equipment room door and installation was a simple matter of re-attaching the two skids, installing the storage tanks, and making the supply, return, and cold water connections. A single point power connection was also included on the skid.
The package was designed to accommodate two additional water heaters in anticipation of a likely expansion to the hotel. Each of the current modulating heaters has a 5:1 turndown for an overall 20:1 modulating capability. The water heaters have an internal cascading sequencer that adjusts the firing rate to efficiently meet demand.
The most unique feature of this package, however, was the built-in variable speed recirculation system, designed to efficiently meet the needs of three distinct pressure zones at the hotel. With city water pressure entering the building at 110 psi, a pressure reducing valve (PRV) was needed for the ground level kitchen area to reduce pressure to 55 psi, and then another PRV for the first four floors of guestrooms to reduce pressure to 65 psi. The upper floors did not require a PRV. All this made for a tricky and potentially wasteful instant hot water delivery system. A constant speed system would have been extremely inefficient given the unique pressure demands of each zone.
Three eSV recirculation pumps were installed along with Square D variable speed drives on the prepackaged system. The pumps are controlled based on the return water temperature, increasing speed as temperature drops and then decreasing again as the water gets up to temp to minimize horsepower usage.
The pre-packaged components facilitated installations and the new system was up and running in time for the big game.
JMP Technical Support and Start Up Specialist, Sam Beck was there to oversee the piping work and commission the wiring of all the controls. He also did start-up of Lochinivar units, assuring that the controls were properly programmed and that the combustion system and drives worked properly.
Despite the fact that this uniquely designed package was unlike any other that Hyfab had built or JMP had sold, the start-up was as near perfect as any Sam had ever seen.
“It really turned out to be a spectacular project. We were able to verify that all the correct temperatures were being supplied to the different pressure zones and also observe that the water heaters are operating at 97-98% efficiency in the field,” said Sam.
Downtime was less than 5 hours during the two-day retrofit and hotel guests were only without hot water for two hours during the middle of the night, since an existing tank was able to take up the slack. More importantly, since then hotel guests have been treated to on-demand hot water (no waiting!) while the hotel enjoys the benefits of a more reliable and far more efficient hot water system.