Deaerators are large insulated tank-car-shaped pressure vessels that produce preheated boiler feedwater. In this January 2010 article, Gary Wamsley, PE, CEM, discusses benefits of deaerators, provides a checklist for determining the operational integrity of deaerators, and explains how deaerators provide critical information for evaluating plant operations and identifying energy-saving opportunities.
Condensing hydronic boilers enable efficient control and delivery of heat when and where heat is needed. In this June 2012 article, Alan Wedal discusses advantages of hydronic boilers over steam boilers, transitioning from steam systems to hydronic
systems, benefits of hybrid systems (systems utilizing both condensing and non-condensing boilers), economics of hydronic systems, ways to achieve dramatic energy savings
with condensing boilers, hydronic-boiler controls,
and the decentralization of boiler rooms.
A confluence of economic, environmental, and national-security concerns has led to renewed interest in natural-gas heating. But while natural-gas heating has increased, technology largely has failed to keep pace. In this August 2012 article, Martin J. McDonough and Stephen Lafaille explain how advances in internal-combustion-engine technology in the automobile industry have led to significant improvements in the reliability and efficiency of natural-gas-engine-driven heat pumps and how new emissions-control technology has led to cleaner emissions and lower criteria pollutants (contributors to smog).
The Adam Joseph Lewis Center (AJLC) for Environmental Studies on the campus of Oberlin College in Oberlin, Ohio, is one of the nation’s most widely publicized green buildings. Showcasing a variety of energy-efficient strategies and technologies, the 13,600-sq-ft building is the winner of numerous architecture awards and was named the most important green building constructed since 1980 in a poll of green-building experts and advocates. In this January 2013 article, John H. Scofield discusses how the AJLC failed to meet a key design goal for years and calls into question the scientific value of high-performance-building case studies.
The United States has achieved a new level of consciousness regarding the environmental impact of the boilers it manufactures, specifies, purchases, installs, and maintains. Emerging as an environmentally sound and financially prudent alternative to gas boilers is the electric boiler. In this January 2009 article, Sutherland D. Junge discusses benefits and advantages of electric boilers and addresses arguments against their use.
With the inception of the LEED green-building rating program and stricter ANSI/ASHRAE/IES Standard 90.1, Energy Standard for Buildings Except Low-Rise Residential Buildings, and ANSI/ASHRAE Standard 62.1, Ventilation for Acceptable Indoor Air Quality, requirements, the geothermal industry has evolved. In this February 2013 article, Christopher Qualls, PE, CEM, provides an overview of the wide array of geothermal options available to design engineers and commercial-building owners seeking to sharply reduce operating costs.
Condensing boilers can be a highly efficient means of generating and circulating heat, as they recover latent heat from water produced during combustion and minimize cycling losses. In this September 2007 article, Eric Moe, MSE, MBA, discusses how low heating-water return temperature, which is required for high efficiency, can be achieved with industrial-grade pressure-independent control.
Gas-fired absorption heat pumps can be used in commercial heating applications and achieve thermal-efficiency levels as high as 145 percent by drawing heat from renewable energy resources. Absorption heat pumps use natural ammonia-water refrigerant and offer energy savings and carbon-dioxide-emissions reductions of up to 30 percent or more, compared with condensing boilers. In this September 2010 article, James Pettiford, Erin Sperry, Melissa Wadkinson, and Fabio Spreafico discuss how absorption heat pumps offer new opportunities to significantly improve the energy efficiency of schools/universities, hospitals, office buildings, and manufacturing facilities.
Chilled beams are cooling (and optionally heating) units located in or above a conditioned space that utilize a ventilation-only primary air stream from a remote air handler to induce larger recirculating room flows, effectively heating, cooling, and ventilating the space without the use of an in-room fan and with reduced overall airflow from the central air-handling unit. In this November 2013 article, Craig R. Buck, PE, LEED AP, HFDP, discusses benefits and challenges related to the use of active chilled beams in health-care settings.
In this April 2013 article, the Global Field Devices Business of Honeywell Inc. provides tips for selecting globe, ball, butterfly, two-way, quick-opening, linear, equal-percentage, three-way, mixing, and diverting valves.
Although heat exchangers usually are selected for unique sets of conditions, sometimes it is of interest to know how they will respond to changes in inlet temperature. In this January 2005 article, Jim Breese explains a method, based on heat-transfer effectiveness and number of heat-transfer units, for predicting responses to changes in conditions.
Regardless of their size and type, boilers can be dangerous, causing loss of life and significant property damage, if not inspected and maintained properly. In this April 2009 article, Stephen Kleva discusses the increased stringency of boiler-inspection laws and the growing problem of overdue inspections, explains features of boilers designed to prevent accidents, and shares tips for improving the efficiency of boiler heat generation.
While the boilers of today are nothing like those from earlier times, we still seek to balance safety and performance. Today, our business climate demands we add economics to the equation, viewing the boiler as an investment in efficiency and sustainability. When should I replace my boiler? How long will my boiler last? How can I minimize life-cycle costs? All are important questions for a facility manager or owner and are addressed in this September 2012 article by Dan Bulley, LEED AP BD+C, O+M.
Operators of industrial-size centralized hot-water- and steam-generating facilities on college, hospital, and government campuses are under increasing pressure to restrict nitrogen-oxide (NOx) emissions, as state environmental agencies enforce federal law intended to decrease respiratory-related health concerns. In this January 2013 article, Vince Basilio, PE, CEM, answers the questions of how low you can go and how low you need to go in terms of NOx emissions.
Hydronic heating systems are becoming increasingly common in commercial buildings, playing an ever-expanding role in high-performance design. In this January 2014 article, Peter D’Antonio, PE, CEM, LEED AP, discusses tried-and-true methods of minimizing costly mistakes and maximizing efficiency.
The first step in most HVAC design projects is to calculate heating and cooling loads. These calculations become the basis for sizing equipment and, when required, projecting energy use. While energy-use projections can be data- and calculation-intensive, even the most sophisticated procedures consist of little more than calculating the heating or cooling load at each outdoor temperature of interest, multiplying by the number of hours of each outdoor-temperature occurrence in a year, and summing. In this September 2013 article, Kenneth M. Elovitz, PE, Esq., explains how engineers can apply the process in reverse: use historical energy-use and weather data to infer building heating or cooling loads and understand how a building uses energy.
Current boilers incorporate knowledge gained from more than 200 years of engineering advancements in design, metallurgy, fabrication, controls, and supervisory systems. Boiler failures, however, still occur, causing businesses to suffer losses of production, income, and, worst of all, life. Because it is known how and why they occur, these failures are preventable. In this August 2008 article, Jerry Theodorou discusses the three major causes of boiler failure—low water, corrosion, and scale/sediment accumulation—and ways to prevent them.
In this June 2010 article, Don Wolf discusses new, stricter U.S. Environmental Protection Agency air-emissions requirements for industrial, commercial, and institutional boilers.
In this January 2014 article, Gary W. Wamsley, PE, CEM, recalls his investigation into and solution for a boiler-feedwater-pump-performance issue at an industrial facility.
In this December 2011 article, adapted from the book “HVAC Design Guide for Tall Commercial Buildings,” Donald E. Ross, FASHRAE, discusses ways to minimize stack effect, the phenomenon by which a tall building acts as a chimney in cold weather, with the natural convection of air entering at the lower floors of the building, flowing through the building, and exiting from the upper floors.
The decision to retrofit or replace a boiler involves specific criteria impacting various areas of a steam or hot-water-heating facility, such as operations, the physical plant, and budget. In this January 2009 article, Steve Connor discusses retrofit and replacement criteria for various boilers.
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