MMAE Seminar - Rethinking Steam Heat… A High Efficiency, High Comfort Alternative for Today

Armour College of Engineering's Mechanical, Materials & Aerospace Engineering Department will welcome Alumnus and Owner of The Steam Whisperer, David Bunnell (Arc '89) on Wednesday, December 2nd to present his lecture, Rethinking Steam Heat... A High Efficiency, High Comfort Alternative for Today.

Abstract

For decades there has been a belief held by engineers, architects, contractors and the general population that low pressure steam space heating systems are inherently inefficient, troublesome, noisy, difficult to control and simply out of date. It has also been said for many decades that there is no sense in making any investment in training or equipment since this technology will soon be gone. However, when one begins to explore the technology of low pressure steam heating, the facts paint a much different picture.

Low pressure steam space heating systems are heating systems that typically operate at a maximum of 2 psi positive pressure to about 23 inches mercury vacuum. They are found in structures of all sizes and all uses. There is a massive installed base of these systems found in virtually all major Northern cities throughout the United States, and also can be found in many structures found in warmer climates, such as structures in California and North Carolina. The systems receive steam from either independent steam boilers or from central high pressure steam plants serving multiple buildings that often have miles of underground steam piping networks. Some of the best known buildings that are equipped with steam heating are The White House in Washington, D.C. and The Empire State Building in New York City. New York City also has the world's largest high pressure steam system serving about 1/4 to 1/3 of Manhattan.

When setting aside the popular notions, the hype of high efficiency ratings of equipment, and getting back to the fundamentals, the picture that forms is one of inherently high system efficiency, exceptional comfort control possibilities, delivery of high comfort levels, and room for further efficiency improvements when systems are equipped to take advantage of newer technologies.

Steam heating takes advantage of the fundamental properties of the earth's most common element....water. By raising the temperature of water to a relatively low temperature, 100 C or 212 F at typical atmospheric pressures, a phase change occurs and the liquid becomes a gas. When delivered to a space heating unit (typically a radiator) the gas becomes a liquid again to release heat. The use of this simple process allows enormous amounts of heat to be moved with very little effort.

When considering efficiency, comfort and health safety, these are a few observations when comparing steam to other typical heating systems:

1. Steam requires no additional power to move heat to living spaces, nearly eliminating the need for electrical power for operation.
2. Parasitic system losses are easily addressed by simply insulating the piping system. Other typical systems required difficult duct sealing and the addition of insulation, yet still yield poor performance.
3. Steam systems are much more compact than forced air, requiring less floor area and headroom for distribution.
4. Steam systems are available that can use piping about the same size as hot water for even more compact systems.
5. Steam systems can use much more compact heat emitters in spaces than hot water, roughly the same space as forced air vents require.
6. Steam systems typically deliver high levels of radiant heat, which provide higher comfort levels at lower fuel usage.
7. Steam systems typically reduce air leakage dramatically compared to typical forced air systems.
8. Steam systems are easily upgraded or designed for room by room temperature control, improving comfort and efficiency.
9. Steam systems reduce fire hazards and improve building performance during fires.
10. Central steam systems reduce potential occupant exposure to fire or Carbon monoxide hazards.
11. Steam systems do not trap and circulate dust and allergens like other systems.

Issues related to noise, excessive maintenance costs, uneven heating and high fuel usage that are typically associated with steam have several causes that are not inherent to the system

1. Since there has been little to no training for steam system service and design, the systems have not been properly maintained or serviced in decades.
2. Since the buildings these systems service are often 100 years old, there has often been settling or other work that has altered the proper geometry of the piping and created noise and leaks.
3. Over 95% of the boilers are oversized.
4. Over 95% of the boilers are installed incorrectly.
5. Over 60% of the controls are not correctly adjusted.
6. Nearly 100% of the systems have never been converted from coal boiler operation to modern automatic firing operation (oil or gas).

When digging deeper into the characteristics of steam heating systems, it becomes apparent that these systems are a viable alternative today when seeking a system that is very efficient, provides high quality comfort, and excellent control. Existing systems should not be removed, but corrections and deferred maintenance addressed. Taking advantage of newer technologies can also be beneficial.

When looking at choices for new construction, steam should be pursued as a sensible alternative to the much poorer performing alternatives typically used today.

Biography

Mr. David Bunnell grew up in Chicago's Beverly Hills neighborhood, graduating near the top of his class from the excellent local schools. His education continued at IIT, spending 6 years training under some of the world's most respected architects, earning a degree in Architecture, with a specialty in City and Regional Planning. During this period of intense study, he conducted research into affordable housing for Chicago and worked for engineers and architects as a summer intern, ran his own small business, and helped maintain the family's commercial properties. As a property maintenance veteran since childhood, he took apart his first commercial boiler at the age of 12.

After 20 years away from his native city, Mr. Bunnell moved back to Chicago due to high demand for his services in the specialized field of steam heating and a desire to be part of the community found in this great city. He has become a steam heating evangelist due to the tremendous comfort, control and efficiency advantages of steam heating.

Mr. Bunnell publishes and teaches in a number of venues providing support for Condo/Coop association managers, homeowners, commercial property owners, and curators of historic properties with steam heating.