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68•


Retrofit for Conservation Helping to reduce energy demand (Continued from page 66.)


cause the need to “wait” for hot water to arrive at the tap is eliminated. Since the installation, supply is-


sues have been eliminated and the costs of heating the water were dras- tically reduced.


Sunny Hill Nursing Home After reading an article written by


Metropolitan released in a trade mag- azine and also attending a seminar conducted by Metropolitan Indus- tries, the Maintenance Director of Will County approached HVAC Di- vision manager Matt Brickey for his input regarding replacing existing commercial hydronic boilers with a skid-mounted Navien package. The nursing home used their mas-


sive hydronic boilers to supply heat to their domestic hot water storage tank through an internal shell and tube heat exchanger. The problem with this configuration is inefficiency because the huge boilers would short


cycle 24/7 due to satisfying the load quickly, turning off, and then turning back on again shortly thereafter due to a drop in domestic water tempera- ture.


Short cycling causes numerous is-


sues for a heating system. One, it causes more stress on the boiler com- ponents by constant expansion and contraction. Boiler parts will wear and fail quicker than their intended life cycle. The second issue is the amount of wasted heat energy that is thrown up the stack. Each time a boiler turns on, or off, it goes through a purging process. During this process, a substantial amount of en- ergy is lost in the form of wasted heat when the boilers short cycle. Metropolitan’s solution was de-


signing a heating system that can di- rectly heat the domestic water more efficiently and allow the maintenance staff to shut down their existing boiler plant in the warmer months. Metropolitan supplied a skid-


Pictured is a prefabricated domestic heating system skid consisting of eight 98% efficient Navien tankless water heaters, a variable speed supply pump that circu- lates domestic water from the domestic storage tank to the heaters, a control sys- tem and all the necessary piping & valves manufactured by Metropolitan Industries Inc. for Sunny Hill Nursing Home.


mounted 98% efficient Navien con- densing domestic heating system that modulates and heats the existing do- mestic tank without any short cy- cling. A unique feature of these units is the ability to cascade them for high-Btu applications. The system included eight tankless


water heaters, a variable speed supply pump that circulates domestic water from the tank to the heaters, a control system that monitors tank tempera- ture and adjusts pump speed accord- ingly by sensing the flow and all the necessary piping and valves manu- factured on a prefabricated skid for a complete functional system. This sys- tem also allows for ease of installa- tion by the contractor because field work is limited to making piping con- nections from the tank to the skid, bringing electrical power to a single point connection, and running the CPVC exhaust & intake to the out- side wall. The anticipated natural gas energy


savings during the summer months is expected to be a whopping 50% to 75%. In both project examples, the end


user saved money because of reduced energy demand by using Navien con- densing tankless water heaters. Met- ropolitan Industries stocks a large supply of these units in their shop ready for immediate delivery, and can fabricate large custom commercial systems for contractor installation. For more information, contact


See contact information on page 82 • Be sure to visit www.thewholesaler.com for web exclusive articles and videos! •


Mark Brickey at 815-886-9200 or visit their website at www.metropol- itanind.com.


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•THE WHOLESALER® —APRIL 2011


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