CSE Pure Power - Fall 2008 - (Page 15)

cover story 15 ❮❮ PURE POWER // FALL 2008 Chilled water pumps Absorption chiller Motorized isolation valve is open when absorber is operating Electric chiller 1 Electric chiller 2 Chilled water supply Motorized bypass valve open to electric chillers when absorber cannot meet building demand Chilled water return Simultaneous mode Electric chiller mode Motorized isolation valve open when absorber is operating Absorption chiller Electric chiller 1 Electric chiller 2 Chilled water pumps Chilled water supply Motorized bypass valve open to electric chillers when absorber cannot meet building demand Chilled water return Motorized isolation valve is closed when absorber is not operating Absorption chiller Electric chiller 1 Electric chiller 2 or Chilled water pumps Chilled water supply Figure 1: Three chilled water operating modes are depicted: absorption chiller mode (A), where the building cooling load is met using only the waste heat power absorption chiller; simultaneous mode (B), where the cooling load exceeds that capacity of the absorption chiller and an electric chiller must also run; and electric chiller mode (C), where the absorption chiller is not operating and the electric chiller(s) only are serving the load. Source: UTC Power EDITOR’S NOTE: This article is derived from a paper presented by the author at the 16th National Conference on Building Commissioning (NCBC), April 21 to 24. NCBC is owned and managed by PECI. For the original paper and others, visit www.peci.org/ncbc. Consulting-Specifying Engineer is the media sponsor for NCBC. www.purepowermagazine.com Absorption chiller mode C ommissioning combined heat and power (CHP) systems in commercial and institutional buildings requires broad experience. This includes small power plant systems (less than 25 MW), heat recovery, thermally activated technologies, electric switchgear, grid interconnection operation and safety, sound and vibration, emissions control; and building, mechanical, and electrical systems integration. While CHP systems are common throughout industrial sites, accounting for about 84 GW of electric capacity in America, less than 1 GW of power is currently operating in the built environment. The use of CHP systems in buildings is likely to increase as the need to reduce carbon emissions grows and public policy moves to monetize carbon emissions. What is really different about CHP systems? Let’s break it down ﬁrst by major components and then examine the integrated system. Continuous duty drivers: CHP power systems consist of reciprocating engines generally less than 10 MW, microturbines of 65 to 250 kW, and combustion turbines of 1 to 15 MW. Fuel cells also are in use between 5 kW and 1.5 MW, but are generally quite expensive at this time. Emissions: On-site combustion requires a ﬁrm understanding of the federal, state, and local air permit requirements. Air permits are essential before construction starts. Generally speaking, all of these power technologies are capable of being sited anywhere in the United States, with perhaps a few counties in California limiting the use of state-of-the-art reciprocating engines even with after-treatment. The principal question for emissions is generally a matter of cost, and not feasibility. Generators: There are two principal classes of generators: induction and synchronous. An induction generator produces electrical power when its shaft is rotated faster than the synchronous frequency of the equivalent induction motor. An induction generator is not self-exciting, meaning it requires an external supply to produce a rotating magnetic ﬂux. The external supply can be from the electrical grid or from the generator itself once it starts producing power. A synchronous generator is a machine that generates an alternating voltage when its armature or ﬁeld is rotated by an engine Motorized bypass valve is open to bypass loop when absorber can meet building demand Chilled water return http://www.peci.org/ncbc http://www.purepowermagazine.com

Table of Contents Feed for the Digital Edition of CSE Pure Power - Fall 2008

CSE Pure Power - Fall 2008 In the News Commissioning CHP Enhancing Emergency Lighting Data Centers for Uncle Sam Handling a Nuisance Trip Sustainable Projects and Partnerships New Products Ad Index

CSE Pure Power - Fall 2008

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.