Engineered Systems - March 2009 - (Page 32)

Teaching An Old School Flowmeters in different zones of the building represent another consideration that the design engineer commonly ignores (and/or the contractor fails to install). the local winter drybulb to 90°F. We planned this in order to have a morning warmup sequence that can rapidly bring the building temperature up to a comfort level. During building warmup, all outdoor airflow is blocked, and the supply air temperature increases rapidly. During this time, the reheat coils at the terminal units remain closed. Once the building is at operating temperature, the outside air (OA) dampers open, and the OA is brought into the buildings as required by ASHRAE Standard 62 and the International Construction Code. All reheat coils were selected to increase the temperature from 53°. At all times, the AHU supply air temperature, either by pre-heating the air or by bringing enough OA to maintain such temperature during the winter months, is at 90° to maintain space temperature. With the energy management and control system (EMCS), the mixed air temperature can be monitored, and increase OA in an economizer mode during the heating season to maintain a 53° at all times. ALTERNATE PLANNING Because of the alternate designs, the design engineer must evaluate the hydronic system under all possible scenarios (e.g., with only one alternate design accepted, all alternates, and no alternates). With the help of equipment representatives, we evaluated the situation and ensured that we were selecting a pump that could perform under all alternate designs scenarios, giving the owner the ability to make upgrades to those areas of the building that had fallen under alternates at a later time, without requiring major changes to the pumping systems. All piping was designed with the whole building load (e.g., all alternates had been accepted and could be installed at any time). During construction, all three schools were occupied; only partial areas were renovated at a time, and the pump had to properly function at every phase of the project. THINKING IT THROUGH As the design engineer, always consider a bypass with a temporary circuit setter and to have it removed before moving to the next phase. Flowmeters in different zones of the building represent another consideration that the design engineer commonly ignores (and/or the contractor fails to install). STANDARD FEATURES LAARS Mighty Therm2 boilers and water heaters for quality and economy Specifically designed to meet the needs of the replacement market, Mighty Therm2 commercial boilers and water heaters feature straightforward controls with 2-stage firing and convenient modular construction. These versatile and environmentally friendly (NOx emissions below 10 ppm) commercial systems are built for the most demanding indoor and outdoor applications. Available in 7 sizes from 500 to 2000 MBTU/h, Mighty Therm2 boilers and water heaters deliver efficiency levels up to 85%. Their high-efficiency combustion can cut fuel costs significantly compared to conventional water heating systems. In addition to high efficiency, the Mighty Therm2 saves on installations and start-up costs with the optional factory-mounted pump and simple terminal strip for field wiring connections. You can count on Mighty Therm2 performance and low maintenance to deliver the savings. Input 209 at www.esmagazine.com/instantproductinfo ® • Efficient 10-tube finned heat exchanger available in copper or cupronickel • Vents horizontally up to 50 feet • Water heater meets the ASHRAE 90.1 standard for efficiency • Glass-lined cast iron or bronze headers and non-ferrous waterways Built to be the Best™ www.Laars.com 800.900.9276 ©2008, LAARS Heating Systems. All rights reserved. 32 En g i neer ed Sy stem s March 2009 http://www.Laars.com http://www.Laars.com http://www.esmagazine.com/instantproductinfo

Table of Contents Feed for the Digital Edition of Engineered Systems - March 2009

Engineered Systems - March 2009 Contents Editor’s Note Back2Basics Case In Point Commissioning Building Automation HVACR Designer Tips Application Checklist Teaching An Old School New Tricks Basics For Absorption Chillers A New Haven For Sustainable Schools Glossary Classifieds Advertiser Index Tomorrow’s Environment

Engineered Systems - March 2009

For optimal viewing of this digital publication, please enable JavaScript and then refresh the page. If you would like to try to load the digital publication without using Flash Player detection, please click here.