Situation
DuPont Santa Clara is a warehouse refilling site located in Ectepec, Mexico State, which is 40 km outside of Mexico City. There are two conference rooms at the site, each cooled by a Trane split system cooling condenser with a three-ton Climattuff Scroll compressor and 3-HP evaporator. The systems were originally charged with R-22 in September 2001.
The condenser units are located on the roof of the building and the evaporators are located inside the conference rooms.
DuPont Santa Clara decided to retrofit these systems to be more environmentally acceptable.
They chose to use ISCEON™ MO59 because of its proven performance, ease of retrofit and non-ozone-depleting properties.
Retrofit
"This was a quick and easy retrofit," said Salvador Villanueva, a service technician who has worked for Refrigeración STARR for more than 20 years. "Each system took only two hours, which is half the time it normally takes to retrofit a system under similar conditions to those at DuPont Santa Clara."
According to Villanueva, the speed and ease of these retrofits were due to two main factors.
First, he did not have to change the oil because ISCEON™ MO59 is compatible with alkylbenzene (AB), the lubricant that was originally in the system. This saved a considerable amount of time and money that is typically required to remove the oil, flush the system and replace it with new oil. In addition to being compatible with AB, ISCEON™ MO59 is also compatible with other traditional and new lubricants, including mineral oil (MO) and polyol ester (POE).
The second time-saving factor was that the only equipment change or adjustment that Villanueva had to make was replacing the drier filters. Although not required, changing the drier filters is a good practice highly recommended by manufacturers.
During the retrofit, Villanueva recovered 8 kg of R-22 and replaced it with 5 kg of ISCEON™ MO59. A digital thermometer, digital amperimeter and a pressure manifold were used to record conditions both before and after the retrofit.
Benefits Gained
The benefits of this retrofit were immediately apparent. By comparing the data collected before and after the retrofit, it was easy to see that with ISCEON™ MO59, the compressor runs at a significantly lower discharge temperature and pressure vs. R-22. This is likely to prolong the life of the compressor.
Table I. Comparison of discharge temperature and pressure before and after retrofit
|
|
|
|
|
| Discharge temperature, ºC |
48
|
33
|
38
|
35
|
| Discharge pressure, psi |
220
|
205
|
205
|
208
|
The coil air/water out of the evaporator was also lower after retrofitting the system with ISCEON™ MO59.
Table II. Comparison of coil air/water temperature out of the evaporator before and after retrofit
|
|
|
|
|
| Coil air/water out temperature, ºC |
14
|
11
|
15
|
12
|
In addition, with ISCEON™ MO59, the system draws less amperage, which translates to important energy savings.
Conclusion
The retrofit at DuPont Santa Clara was a fast and easy process for the contractor and a
benefit-gaining decision for the site owner. Now, the two cooling systems are delivering
better cooling performance and are more energy efficient thanks to ISCEON™ MO59.
What's more, by replacing the R-22 refrigerant with ISCEON™ MO59, DuPont Santa Clara
is now using a non-ozone depleting refrigerant, which is better for the environment.
