| President-John Cannamela Level II Certified 050916-6 HVAC- journeyman card Universal CFC Serving but not limited the Charlotte ,NC area 704-200-6367 jcannamela@infraredsurve y.com |
 |  |  |  |
| Air StratificationHVAC Systems John Cannamela Charlotte, NC Paper presented and published Introduction This paper presents a new use for an infrared camera, diagnosing and solving problems with air stratification, which I discovered using my 20 years experience in the world of heating, ventilation and air conditioning (HVAC), especially dealing with commissioning and start up of commercial systems. Air stratification means hot and cold air separation or air that is not thermally blended. Through the years there have been many problems that have arisen in the engineering and design of commercial buildings, both before and after installation. Part of my job has been to ensure the building systems are installed to the engineer’s design specification. At time there are unavoidable conflicts between the laws of physics and the laws of a stubborn architect. They say that Doctors practice medicine and lawyers practice law, but contractors have to get it right the first time—whatever the cost. Common problems with airflow One common issue is that the mechanical rooms, where conditioned air is supplied to a beautifully designed building, are very small and confined causing problems with equipment installation. Air handlers, which are the heart of every HVAC system, deliver the air used to heat and cool the space. Heat is either removed or introduced into the air stream by mechanical means, such as a chilled water coil, a DX coil, or electric strip heaters. Laminar flow is the term used to describe air that is evenly distributed. Laminar flow through the air handler is essential to an effective, efficient HVAC system. Achieving this straight, even air movement often requires using ducts of several different diameters to straighten out the moving air. We also need enough velocity, but not too much, in order to utilize the entire cross-sectional area of the coil. Unfortunately, we don't always have these options because we are confined to tight mechanical rooms. If the air does not flow straight and is not evenly distributed across these devices, energy is wasted or, even worse, components may fail or “trip out” and the HVAC system goes down. We don’t want that to ever happen! That’s why we commission these systems and test them to run at their most efficient setting. In the wintertime conditions often permit the use of cold outside air to be used as “free” air conditioning. In such cases the air handler’s damper, which is connected to an outside louver, opens and outside air is drawn into the system. We use 100% outside air when its temperature is above freezing, say between 35F and 50F dry bulb. Air Handler Unit When the outside air is below freezing we have to mix the air with warmer building “return” air that is generally 70-75F. This is accomplished in a return air chamber called a mixing box. Once blended the two mix to produce supply air at about 50-55F to the building. If the outside air louver is too close to the mixing damper or box, the cold outside air is drawn in closer to one side of the coil than the other resulting in non-laminar flow that then causes stratification. This often causes the air handler to “trip out” on low limit to protect the system. Procedure Poor laminar flow may be caused by several things, the most common being not enough distance between the return air plenum and the face of the device, such as a coil, that is the transfer medium. To better understand air flow, we need to measure the temperature of air in the HVAC system. We often try to characterize and measure air stratification across a coil, for instance, by hanging several temperature data collectors at different heights across the air stream. Unfortunately, it would take days to gather and analyze useful data by this method but, until recently, that was all we could do. Before air blending coil not maximised After air blending Coil maximised Now with this new magic we call thermal imaging we can collect the same data in a few seconds. In an air handler I found my infrared camera to be incredibly useful. It’s best to be in a mechanical room with stable conditions. Opening the return door or an access door and taking an infrared shot can result in confusing images, but with most air handlers large enough to have a mixing box, the problem is usually minor. We see the temperature changes on the coil, not the air itself, so I see exactly how the coil is affected. To start the process : 1. First you should have 2 people if possible-1 for the picture and 1 on the disconnect. 2. Be aware that most of time you are looking into the negative pressure side of the unit-things like to get drawn into the unit of which your head is usually in the way but forget that guard your camera. The system may not like the sudden change in pressure-consult the building engineer!!! 3. Unit should be running at normal speed if not mark down the speed for later comparison. 4. Unit should be in full cooling or heating mode; valves open etc.. 5. If possible video would be helpful 6. If you don’t see any change take a delta across the coil if it is good, the airflow is good, if not then see # 4. 7. Results of good or bad are subjective, maximized would be the word of chose. If there is a problem with the image due the access door being open, block most of the opening. Results will not vary too much. In conclusion I find many systems aren’t 100% maximized due the structural components in the unit for example the filter rack and the bracing. However overall if the unit is tripping this is the best tool I have ever used to instantly show myself as well the as the owner the performance of their equipment. I will say HVAC experience is important for this application. Infrared technology is one of the best trade enhancement tools since the cordless drill. We did a lot of work without them but every tradesman has at least one and has found something unique to do with them. I can see in the near future we all will have them like a multimeter. Copyright © 2006 John Cannamela |
| Filters |
| Coil |
704-200-6367
I have been in the Charlotte ,NC area in the HVAC business since 1989, as a tradesman I've had to
find problems and save energy cost for owners on a daily basis.I have written articles for Snell infrared
on infrared techniques in the commercial trade,and national and local TV news .I'm constantly looking
for new ways to use infrared technology for the home owner.
My constant curiosity for high tech trouble shooting techniques lead me to infrared . Infrared is a
perfect marriage for the HVAC trade and the building industry,but there are too many uses to list here.
The highest cost to run a house is the mechanical system,and are dependent of the insulation in the
walls and attic and installation of the mechanical systems. With energy cost constantly rising and high
efficiencies of home and equipment demands thermal imaging can show you where your energy is
escaping. Thats the bottom line of all service companies, is to save you money, but you may not know
how to save unless you see where to stop your loss.
find problems and save energy cost for owners on a daily basis.I have written articles for Snell infrared
on infrared techniques in the commercial trade,and national and local TV news .I'm constantly looking
for new ways to use infrared technology for the home owner.
My constant curiosity for high tech trouble shooting techniques lead me to infrared . Infrared is a
perfect marriage for the HVAC trade and the building industry,but there are too many uses to list here.
The highest cost to run a house is the mechanical system,and are dependent of the insulation in the
walls and attic and installation of the mechanical systems. With energy cost constantly rising and high
efficiencies of home and equipment demands thermal imaging can show you where your energy is
escaping. Thats the bottom line of all service companies, is to save you money, but you may not know
how to save unless you see where to stop your loss.
About Our Business
Facts
Moisture behind walls, over ceilings, and under floors is often impossible to detect until the problem is
excessive and visible to the naked eye. The investigation of not yet visible mold in structures is often
difficult to detect, however with modern technology and infrared diagnostics it is now possible to do what
was once impossible.
According to the U.S. Environmental Protection Agency, there is no practical way to eliminate mold spores
in indoor environment. The best way to control mold growth is to control moisture. Mold can begin
growth in as little as 24 hours. Roof leaks and water pipe leaks are common sources of water
accumulation that may cause mold growth.
Technology has provided a tool that can be used by investigators, remediators and consultants to detect
and help eliminate mold infestations. The technological tool is called Infrared Thermography (IT). It is a
technique that produces an image of invisible (to the human eye) infrared light emitted by objects due to
the heat, or lack thereof, in the object called its “thermal condition.” The most typical type of thermography
camera resembles atypical camcorder and produces live television picture of heat radiation. More
sophisticated cameras can actually measure the temperatures of any object or surface in the image and
produce false color images that make interpretation of thermal patterns easier. An image produced by
an infrared camera is called a thermogram or sometimes a thermograph.
To understand IT as a tool it is necessary to understand how it works. Thermal or infrared energy is light
that is not visible to humans because of its wavelength is too long to be detected by the human eye.
Thermal or infrared energy (IR) is the part of the electromagnetic spectrum that we perceive as heat.
Unlike visible light, in the infrared world, everything with a temperature above absolute zero emits heat.
Even very cold objects, like ice cubes, emit infrared. The higher the object’s temperature, the greater the
IR radiation emitted. Infrared allows people to see what their eyes normally cannot see.
IT cameras produce images of invisible infrared or “heat” radiation. The IT camera can provide precise
noncontact temperature measurement capabilities. The existence of moisture-a substance cooler than
normal construction materials-can be used to detect conditions that promote mold growth. Mold related
problems can be detected before the mold is visible to the eye or detectable by the nose. IT cameras are
extremely cost-effective, valuable diagnostic tools in construction related problems of water intrusion and
mold growth.
But finding a problem with an infrared camera is not a solution. It is the start of an investigation that will
help the property owner or developer stop a problem before it becomes serious. An infrared camera
image alone, without accurate temperature measurements, says very little about the condition of a
structure or its susceptibility to mold growth. An infrared image without measurement can be misleading
because it may visually suggest a problem that does not exist.
The use of a thermal imaging camera can provide valuable information during moisture assessments,
remediation oversight, energy audits, roof and electrical system inspections and water damage
investigations. Temperature difference caused by evaporation, radiation, thermal bridging,
infiltration/exfiltration, and other sources must all be carefully evaluated.
The inspector uses thermal imaging and data logging moisture detections equipment to establish that
the inspector assesses all areas of concern. The extra verification gives additional assurance that the
findings from the IR camera are defensible. All property owners and their insurers faced with a claim
alleging mold infestation can find these tools essential to the decision process and proper maintenance
of the structure.
When suspect areas are found they can be visually documented using the IR camera. Images, like those
obtained from and IR Camera, are easier for a layperson or nontechnical person to understand.
Findings from the insurer
S personnel combined with the verification obtained by using data-logging moisture detection equipment
with the time stamp and/or destructive testing.
The time saved using infrared, and the larger areas covered rapidly by an IR camera, can save time and
money by providing a faster, more efficient and more reliable survey. An IR camera can detect moisture
located behind interior walls under the right conditions. The temperature difference created by the
presence of moisture on the inside surface of a wall will appear differently than the surrounding area. IR
and IT experts recommend that property owners or their insurers should use IR cameras and IT for
moisture detection .
Report shows anomalies-structure should be further investigated buy a skilled tradesman.
Anomalies are temperature differences due to several issues of which water maybe a key factor. This report does not
guaranty the findings of water but to provide further evidence to sample areas that show strong possibilities of moisture or
that water was there at one time.
Copyright © 2006 John Cannamela
Moisture behind walls, over ceilings, and under floors is often impossible to detect until the problem is
excessive and visible to the naked eye. The investigation of not yet visible mold in structures is often
difficult to detect, however with modern technology and infrared diagnostics it is now possible to do what
was once impossible.
According to the U.S. Environmental Protection Agency, there is no practical way to eliminate mold spores
in indoor environment. The best way to control mold growth is to control moisture. Mold can begin
growth in as little as 24 hours. Roof leaks and water pipe leaks are common sources of water
accumulation that may cause mold growth.
Technology has provided a tool that can be used by investigators, remediators and consultants to detect
and help eliminate mold infestations. The technological tool is called Infrared Thermography (IT). It is a
technique that produces an image of invisible (to the human eye) infrared light emitted by objects due to
the heat, or lack thereof, in the object called its “thermal condition.” The most typical type of thermography
camera resembles atypical camcorder and produces live television picture of heat radiation. More
sophisticated cameras can actually measure the temperatures of any object or surface in the image and
produce false color images that make interpretation of thermal patterns easier. An image produced by
an infrared camera is called a thermogram or sometimes a thermograph.
To understand IT as a tool it is necessary to understand how it works. Thermal or infrared energy is light
that is not visible to humans because of its wavelength is too long to be detected by the human eye.
Thermal or infrared energy (IR) is the part of the electromagnetic spectrum that we perceive as heat.
Unlike visible light, in the infrared world, everything with a temperature above absolute zero emits heat.
Even very cold objects, like ice cubes, emit infrared. The higher the object’s temperature, the greater the
IR radiation emitted. Infrared allows people to see what their eyes normally cannot see.
IT cameras produce images of invisible infrared or “heat” radiation. The IT camera can provide precise
noncontact temperature measurement capabilities. The existence of moisture-a substance cooler than
normal construction materials-can be used to detect conditions that promote mold growth. Mold related
problems can be detected before the mold is visible to the eye or detectable by the nose. IT cameras are
extremely cost-effective, valuable diagnostic tools in construction related problems of water intrusion and
mold growth.
But finding a problem with an infrared camera is not a solution. It is the start of an investigation that will
help the property owner or developer stop a problem before it becomes serious. An infrared camera
image alone, without accurate temperature measurements, says very little about the condition of a
structure or its susceptibility to mold growth. An infrared image without measurement can be misleading
because it may visually suggest a problem that does not exist.
The use of a thermal imaging camera can provide valuable information during moisture assessments,
remediation oversight, energy audits, roof and electrical system inspections and water damage
investigations. Temperature difference caused by evaporation, radiation, thermal bridging,
infiltration/exfiltration, and other sources must all be carefully evaluated.
The inspector uses thermal imaging and data logging moisture detections equipment to establish that
the inspector assesses all areas of concern. The extra verification gives additional assurance that the
findings from the IR camera are defensible. All property owners and their insurers faced with a claim
alleging mold infestation can find these tools essential to the decision process and proper maintenance
of the structure.
When suspect areas are found they can be visually documented using the IR camera. Images, like those
obtained from and IR Camera, are easier for a layperson or nontechnical person to understand.
Findings from the insurer
S personnel combined with the verification obtained by using data-logging moisture detection equipment
with the time stamp and/or destructive testing.
The time saved using infrared, and the larger areas covered rapidly by an IR camera, can save time and
money by providing a faster, more efficient and more reliable survey. An IR camera can detect moisture
located behind interior walls under the right conditions. The temperature difference created by the
presence of moisture on the inside surface of a wall will appear differently than the surrounding area. IR
and IT experts recommend that property owners or their insurers should use IR cameras and IT for
moisture detection .
Report shows anomalies-structure should be further investigated buy a skilled tradesman.
Anomalies are temperature differences due to several issues of which water maybe a key factor. This report does not
guaranty the findings of water but to provide further evidence to sample areas that show strong possibilities of moisture or
that water was there at one time.
Copyright © 2006 John Cannamela