High Efficiency Systems
About the Project
Founded as Omaha University in 1908, the current day University of Nebraska at Omaha is now the third-largest institution for higher education in Nebraska. It occupies over 158 acres of land and serves over 15,000 students and faculty. As a part of its expansion, they are adding a new LEED Silver Certified College of Business Administration named Mammel Hall.
With a goal of providing occupant comfort year-round, the owner wanted to insure that the indoor climate would be controlled through potentially humid summers as well as severe winter conditions.
Challenges & Considerations
The Engineer’s original specification called for the addition of a boiler and significant hot water piping. This option would require a boiler to be on standby for the inevitable reheat request in order to maintain humidity control. When asked to consider electric heat as an alternative, recommended by the local Krueger Representative, Air-Side Components, the Engineer originally rejected it, stating that three-state heating was too imprecise and SCR electric heat was too expensive (often adding as much as $400/ zone between heater and controls).
It was not until subsequent discussions with both the Local Representative and Dan Int-Hout, Krueger’s Chief Engineer, that the Engineer switched the specification to electric heat. It actually offered a lower first-cost than the first option because the once needed hot water piping could be eliminated. However, we still had to address an issue with uniformly cooling all spaces. Fortunately, Krueger already had an electric heat solution that would fit that need as well as provide an opportunity to earn LEED points towards their Silver certification. Krueger’s patented LineaHeat™ option features a single-stage, time-proportional solid state relay to provide only the required amount of heat to the space.
The LineaHeat controller optimizes both flow and reheat at a much lower first-cost than SCR electric heat and it has more flexiblity when it comes to controlling it. LineaHeat can accept up to seven different types of input signals, including ON/OFF, 0-10 VDC, and 3-point floating. All seven options are designed to work with standard DDC controllers currently offered on the market today, which can create an opportunity for significant first-cost savings. Additionally, there is an option to allow for precise control of discharge temperatures to maintain space temperatures. This too can be beneficial when there is a need to cost-effectively control humidity.
The End Result
Krueger was pleased to have provided 150 LMHS units with LineaHeat for this application and the opportunity to help achieve LEED Silver Certification on this building. The Engineer also stated that the installation has gone smoothly and that they are on target to open in August of 2010. LineaHeat allows a simple startup with little field adjustment required. The optimization of energy use that LineaHeat provides has assisted the customer in obtaining his LEED Silver rating.