Like most things in Texas, the plans to upgrade the heating and hot-water systems at the University of North Texas in Denton are big. While the project involves the installation of nearly 70 boilers and water heaters, the largest part of the renovation may be the energy savings associated with the new systems.
A Highly Efficient Plan
The first phase of the project was focused on the central steam plant and outlying administrative and educational buildings. The existing steam and hydronic boilers peaked at 80-percent efficiency.
AERCO Benchmark 3000 (BMK3000) high-efficiency boilers, which have full-fire input capacity of 3 million Btuh, were installed in each outlying building. The retrofit went off without a hitch, and the units began reaping benefits almost immediately. Following the conversion of the outlying buildings, five BMK3000 units were installed in the central plant.
The facilities department chose Benchmark boilers because of their low cost of ownership, which can be attributed to:
- High efficiency: With a 15:1 turndown, BMK3000 boilers achieve 96-percent efficiency to maximize fuel savings.
- Uptime reliability: A stainless-steel heat exchanger increases the reliability and life of the boilers.
- Maintenance: Compared with the previous system, maintenance is minimal and, thus, service costs are lower.
Making Students Comfortable
Heating and hot-water systems serving the residence halls also were in need of upgrades. A steam boiler and a mix of either indirect steam storage-tank heaters or direct-fired storage heaters operating at 82-percent efficiency were used in each dormitory.
Given that the housing facilities’ domestic-water-heating requirements equaled or exceeded their space-heating requirements, a water heater, rather than a boiler, was necessary. The AERCO Innovation 1060 tankless on-demand water heater was chosen. Like the Benchmark family, Innovation units have a small footprint, a reliable stainless-steel heat exchanger, and efficiency of 96 percent.
Six Innovation 1060 water heaters were installed in three dormitories and the Student Events Center. At Kerr Hall, two units were installed with zero side clearance in the same footprint as a 250-gal. storage heater. One Innovation unit now handles the entire load of the 300-room dorm without the need for storage. By installing two water heaters, the university can alternate between units monthly to extend unit life. Another benefit is the tankless design, which virtually eliminates the risk of Legionella bacteria growth.
Five more dormitories will be retrofitted with Innovation units by the end of 2014. In all, 16 Innovation and 50 Benchmark units will have been installed across the 900-acre campus.
Significant Energy Savings
The university has been experiencing efficiency benefits throughout the renovation. For example, during the 2012-2013 heating season, the central plant consumed 6,465 mcf of gas, 57-percent less than it consumed the prior heating season.
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