Air-cooling evaporators used in ammonia systems have traditionally been made using galvanized (zinc-coated) carbon steel. There are other metals that are compatible with ammonia, including stainless steel and aluminum. Aluminum, in fact, can provide several benefits.
Air duct leakage should be a concern to both the designer and the
building owner because of its potential impact on initial construction costs,
energy usage, and system performance. No matter the size, the total benefit of the
duct system is based and measured on the peak fan efficiency for that system.
The six basic steps of brazing are highlighted: good fit and proper clearance; cleaning the metals; fluxing the parts; assemble for brazing; brazing the assembly; and cleaning the brazed joint.
Boiler “short cycling” occurs when an oversized boiler quickly satisfies process or space heating demands, and then shuts down until heat is again required. This article points out the inefficiency of short cycling and provides suggested actions to maximize boiler efficiency.
Remember that automatic control systems are automatic in operation, but not self-repairing. Unless a building has a service contract with a reputable controls contractor to inspect and calibrate the HVAC control system every six months, it is very likely that the HVAC system is not providing maximum comfort.
Safety of the appliance should be the primary goal of all technicians. The production of carbon monoxide (CO) in the flue gases should be kept below 100-ppm air-free, even though the allowable limit in the stack is 400-ppm air-free.
In a workspace world driven by demands for anytime, anywhere information, wireless technologies are becoming dominant. A flexible wireless infrastructure that supports IT networks, security applications, HVAC, and more is emerging as a surefire way to increase the value of commercial office space.
While hackers and viruses often garner the most attention in the realm of computer threats, many contractors overlook the ways that physical damage can adversely impact their business. Computer hardware failure, power surges, and/or damage from flood or fire could destroy years of work orders, accounting records, and more.
Sometimes it is advantageous to use more than one fan in a system. The fans may be located in close proximity to each other, or separated by quite a distance such as a supply and exhaust fan. Most often there is some compelling reason to use more than one fan in a single system.
This article focuses on stand-alone data loggers
in conjunction with the logging capabilities of the BAS in the context of use
by a commissioning provider. It also provides tips on specific
procedures and techniques that will enable the efficient and effective use of
data loggers to analyze building performance.
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