QCC Air Conditioning:
Stay Cool for Years to
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Line Of Spine Fin Coil
Air Conditioners

Unlike forced air heating, air conditioning is a delicately balanced system that requires the right amount of heat, refrigerant, and airflow to function properly. If proper sizing is to be considered important for heating it should be considered crucial for air conditioning. Lets look at the ways a sizing calculation can insure proper air conditioner operation, but first we need to understand how refrigeration/air conditioning works.

Starting at the outside unit (condenser) refrigerant is pumped at high temperature/pressure as a liquid inside to the evaporator coil. Before the refrigerant enters the coil it must enter through a metering device (cap tubes, flow control check valve, or thermal expansion valve most commonly) that will cause the refrigerant to drop significantly in temperature or “flash”. At this point the refrigerant will run through the coil evaporating into a vapor as the warm air from your home passes over it. Once fully evaporated the refrigerant makes its trip back to the condenser in a low temperature/pressure state. The compressor inside the condenser compresses the vapor into a high temperature/pressure vapor. The refrigerant then travels through the outdoor coil inside the condenser as the condenser’s fan serves to cool it. By the time refrigerant has gotten to the end of the outdoor coil it has cooled to a high pressure/temperature liquid and is ready to be pumped back to the evaporator coil. Interestingly enough, the bigger the outdoor coil the better the SEER (Seasonal Energy Efficiency Ratio), explaining the large size of the more efficient air conditioners.

What is it that makes sizing so important? Well it all focuses around the evaporator coil. During the evaporation the exact amount of airflow/heat must be applied or the refrigerant will a) boil off too soon or b) not boil off completely by the time it reaches the top of the coil. The refrigerant will boil off too soon if the motor in the furnaces is too large or if the coil is too small. The refrigerant will not boil off in time if the furnace is too small, the duct work cannot provide enough air, the evaporator coil is too big, or the system filter is dirty (to learn more about filtration click here). If you had the right size furnace in your house, for example, but the ductwork was inadequate the air conditioning would function improperly because of the lack of airflow across the evaporator coil. You cannot push 4 tons of cooling into 2 tons of ductwork, it is simply not possible. Let's say you have good ducts but your furnace is too big and spreads too much heat on the coil. In this case the coil will fail to keep up with the airflow and therefore fail to cool the air. In any case you will not only be unhappy and uncomfortable but improper sizing can lead to system breakdown such as replacing a compressor ($800 and up!).

Once you have established what size air conditioner is right for your home you must consider what efficiency or SEER is right for you. Currently single stage cooling has a range of 13 SEER to 15 SEER with two-stage cooling ranging from 16 SEER to 19 SEER. Note: you must have a variable speed furnace in order to utilize two-stage cooling. In relative terms, as you jump from one SEER rating to the next up (I.E. 13 SEER to 14 SEER) you can expect about a 7% savings on your energy bills. Besides the money you save and the better warranties associated with higher SEER Ratings two-stage cooling has other benefits.

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Two-stage Cooling

As of now Trane sells two models in two-stage cooling: the XL16i (16 SEER) and the XL19i (19 SEER). The 16 SEER has a two-stage scroll compressor that will run at a lower speed during moderately warm temperatures and will utilize full capacity on the hot to very hot days. The 19 SEER model actually has two different compressors with different tonnages (1 ton of air conditioning removes 12,000 BTU/hr.). As discussed on our Heating Page (download a sample load calculation pdf here) load calculation design temperature is based on extreme situations. About 85% of the summer months we do not need the full capacity or tonnage of our air conditioner. Therefore, it makes perfect sense to have an air conditioner that can act like two different sized air conditioners: one servicing you most of the summer with the other ready to take care of the really hot days if you need it. In fact, the Trane 19 SEER is such a good buy that it was rated “Consumers Digest Best Buy in the Premium Category”.

To give 2-stage AC a practical look let's look at a load calculation done on the same house with three different outdoor ambient temperatures:

Click here for a larger image.

Note that on a 100° day the full 3 tons was needed, but on a 78° day only half as much was needed. Here in Denver we can truly appreciate the advantages of 2-stage cooling with our generally cooler weather with occasional heat waves.

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Need More Reasons to go with Trane?

Trane is the only manufacturer to have:

• Weather guard top

• Made of durable polycarbonate material shielding unit from leaves, ice, and other debris directing noise and air up and away from plants.
• Integrated Fan Orifice
• Not only is the fan supported by a four-corner system and not resting on the actual coil like Trane competitor models, but its unique mounting improves airflow and provides for quieter operation.
• All aluminum Spine Fin Coil
• A unique, patented design, Trane’s Spine Fin coil is a system of continuous tubes helping to prevent refrigerant leaks, give the lowest possible airflow resistance, and the most efficient heat transfer.

• Galvanized Steel Louvers
• Like most leading manufacturers Trane utilizes a baked-on powder paint finish that protects your unit from rust and corrosion. However, UNLIKE other leading manufacturers, Trane’s louvered system protects the spine fin coil from damage and debris. This directly affects the homeowner as a damaged or dirty coil is only going to serve to lower your SEER rating and therefore raise your energy bills!
• Longest Lasting Condenser
• Going with Trane ensures you a long lasting, headache free experience. Read the story of Trane’s legendary air conditioner Snowball: Click here.

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Spine Fin Coil and the alternative

The two main types of outdoor coils available on the market today are the spine fin and plate fin coils. Trane began full-scale production of the spine fin coil in 1968, and today it ranks as the most efficient heat exchanger currently on the market. What makes it so efficient? To answer this question we need to examine the three main areas that can cost a homeowner time and money:
Leak Protection,
Outdoor Corrosion,
and Cleaning vs. Performance.

Leak Protection

Plate fin coils are made of aluminum plates with stacking copper tubes running through their centers. Each pair of copper lines requires an end-turn to connect the two tubes. In contrast, the spine fin coil utilizes a continuous spiral that wraps around the inside of the condenser with much fewer brazed joints. The average plate fin coil has about thirty brazed joints while Trane’s spine fin coil has about ten. That’s about a 33% less chance of leak potential.

As with other manufacturers Trane uses copper tubing to complete the refrigeration circuit. As talked about in outdoor corrosion the more dissimilar two metals are, the more prone they are to corruption. Because of this Trane utilizes ultrasonic pre-tinned zinc rich aluminum solder. This solder is sacrificial protecting both the copper and the aluminum from corrosion. A five year survey from Trane’s Product Service Department found that a leak rate of only 0.05% over five years was found in the two million plus coils of various sizes that were examined. Back to Spine Fin Coil.

Outdoor Corrosion

The outdoor coil is THE determining factor in the continued efficiency of your air conditioner. Because of this reason, outdoor corrosion must be avoided at all costs. The spine fin coil has the lowest corrosion potential of ANY outdoor coil technology. There are two main types of corrosion: galvanic and crevice.

Galvanic corrosion occurs when two dissimilar metals in close proximity are exposed to a conduction fluid. Some common examples would be salt spray, acid rain, or chemically tainted rainwater. Once exposed the two metals will deteriorate each other. Copper and aluminum are very dissimilar metals with high potential of corrosion. Thankfully, with the unique system used in Trane’s spine fin coil to join the two metals there is about a 1/3 chance of corrosion compared to a plate fin coil.

Crevice corrosion is defined as a corrosion occurring in small paces from a stagnant solution (I.E. rain water). Even a space as small as a few thousandths of an inch - as found between tubing and plate fins - is enough space to potentially cause crevice corrosion. As discussed earlier, plate fin coils are made from rows of copper tubing running through aluminum plates. The copper tubes are mechanically enlarged inside the plates in order to make contact. The problem, however, is that copper and aluminum expand at different rates and over the years that few thousandths of an inch can grow giving greater potential to crevice corrosion.

The Trane Spine Fin coil is made of many aluminum spines tightly wrapped around an aluminum tube with and adhesive that leaves little or no room for corrosion. Further, using aluminum through an entire coil has natural protection against acid rain (unlike copper), not only because of the oxide film on its surface, but also because aluminum alloys have a high resistance to dilute sulfuric acid and hydrogen sulfide found in outdoor environments.

It is because of both galvanic and crevice corrosion that Trane has also recently began manufacturing aluminum indoor coils to further promote functionality in air conditioning systems. Back to Spine Fin Coil.

Cleaning vs. Performance

The cleaner a coil stays the more efficient it functions. To begin with, Trane’s Spine Fin coil is protected by the galvanized steel louvers that come with EVERY model they sell. Although impossible to keep all dirt and debris off of the coil the true genius of the design is yet to come into play! If build up on the spine fin occurs it is insignificant to its performance as the thousands of spine tips distribute the buildup to the depths of the coil. Compare how a Trane Spine Fin coil compares to a plate fin coil after years of NO CLEANING:

Click here for a larger image.

Of course, we recommend that you clean you coil annually because although you may not experience a loss of performance your energy bills will be affected. With Quality Climate Control and Trane you can be sure that you have the most reliable, worry free, quietest operating air conditioner on the market. Back to Spine Fin Coil.

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Look below to see the available models
and call us today!

XL19i

• Duel compressor cooling
• Variable speed fan
• 2 stage cooling
• Weatherguard top
• Compressor Sound enclosure
• Duratuff basepan
• Galvanized steel louvers
• Powder paint finish
• All-Aluminum spine fin coil
• Climatuff compressor
• SEET (System Extreme Environmental Testing) tested
• R22 Refrigerant
• 10 year Compressor, coil, and part warranty
• 10 year warranty blankets furnace in full system purchase
• Voted “Best Buy in Premium Category” by Consumer Reports

XL16i

• 2 stage speed fan
• 2 stage cooling
• Weatherguard top
• Compressor Sound enclosure
• Duratuff basepan
• Galvanized steel louvers
• Powder paint finish
• All-Aluminum spine fin coil
• Climatuff compressor
• SEET (System Extreme Environmental Testing) tested
• R410A Refrigerant
• 10 year Compressor, coil, and part warranty
• 10 year warranty blankets furnace in full system purchase

XL15i

• Single stage Cooling
• Weatherguard top
• Compressor Sound enclosure
• Duratuff basepan
• Galvanized steel louvers
• Powder paint finish
• All-Aluminum spine fin coil
• Climatuff compressor
• SEET (System Extreme Environmental Testing) tested
• R22 Refrigerant
• 10 year Compressor, coil, and part warranty
• 10 year warranty blankets furnace in full system purchase

XL14i

• Single stage Cooling
• Weatherguard top
• Compressor Sound enclosure
• Duratuff basepan
• Galvanized steel louvers
• Powder paint finish
• All-Aluminum spine fin coil
• Climatuff compressor
• SEET (System Extreme Environmental Testing) tested
• Available in either R22 or R410A refrigerant
• 10 year Compressor, coil, and part warranty
• 10 year warranty blankets furnace in full system purchase

XR14

• Single stage cooling
• Duratuff basepan
• Galvanized steel louvers
• Powder paint finish
• All-Aluminum spine fin coil
• Climatuff compressor
• SEET (System Extreme Environmental Testing) tested
• Available in either R22 or R410A refrigerant
• 10 year Compressor and coil warranty
• 5 year part warranty

XR13

• Single stage cooling
• Duratuff basepan
• Galvanized steel louvers
• Powder paint finish
• All-Aluminum spine fin coil
• Climatuff compressor
• SEET (System Extreme Environmental Testing) tested
• R22 refrigerant
• 10 year Compressor and coil warranty
• 5 year part warranty

XB13

• Single stage cooling
• Duratuff basepan
• Galvanized steel louvers
• Powder paint finish
• All-Aluminum spine fin coil
• Climatuff compressor
• SEET (System Extreme Environmental Testing) tested
• R22 refrigerant
• 5 year Compressor, coil, and part warranty

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