Ashrae Journal - December 2008 - (Page 14) ate control strategy and provides the added benefit of improved control for highly variable latent loaded spaces and an opportunity for additional fan energy savings. Operating at 1–1.2 in. w.c. (250–300 Pa) plenum pressures need not have a dramatic effect on fan energy if an extended plenum duct design is applied to the system, minimizing downstream duct pressure losses. This pressure, otherwise lost in duct air transport, is then available for more beam capacity with little waste and would share the duct design philosophy prescribed by REHVA. We do not contest the facts presented as observations made in the submitted letter, and concede that all are valid points, save the suggestion that comfort would most certainly be compromised. Depending on the project conditions and design, these suggestions are an excellent opportunity to extend the savings potential of this technology. We are simply offering a design approach that uses the advantages offered by modern building automation and provides an optimization of capital costs without sacrificing comfort, provided the system is coupled to an appropriate control system. Traditionally, North American buildings have been designed for shorter life spans than their European counterparts. Thus, the amortization of the additional costs relative to a European design philosophy is, in our opinion, more difficult to justify. Incrementally, the minute decrease in operating efficiency provides substantial capital cost savings and remains infinitely superior to many competing HVAC technologies. As such, our approach may remain of interest to design consultants and building owners until such time as the increased capital investment can be justified in terms of additional active chilled beams vis-à-vis energy costs in North America or longer building life cycles are adopted. Darren Alexander, P.Eng., Nisku, AB, Canada Mike O’Rourke, Highlands Ranch, Colo. www.info.hotims.com/16020-9 14 ASHRAE Journal December 2008 http://www.bryanboilers.com http://www.bryanboilers.com http://www.info.hotims.com/16020-9
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.