AirRevive compared the operation of two hotel guestroom vertical fan coil units. The property is located in New York City. The study was conducted during August 2014.
Make: IEC
Model: MPY03
Year: 1997
Configuration: Vertical
The purpose of the study was to compare the performance of the existing fan coil unit with a PSC motor against the performance of a fan coil unit retrofit with an EC motor.
Existing Unit
PSC Motor Horse Power: 1/30
Retrofit Unit
EC Motor Horse Power: 1/8
The following operational performance data was monitored from each unit between August 12th and August 29th, 2014:
The MPY03 model is designed to produce airflow between 330 and 200 CFM.
The airflow from the unit retrofit with an EC motor is programmed on high speed to 331 cfm and low speed to 227 cfm. This airflow is aligned with the manufacturer’s specifications.
When the airflow is aligned with the manufacturer’s specification the air moves across the coils and fins at the correct speed. This facilitates proper heat transfer thus cooling or heating the air efficiently.
CFM PSC Motor CFM EC Motor
High Speed 407 331
Low Speed 302 227
884,760 watts reduced on high fan – 70% reduction
719,000 watts reduced on low fan – 80% reduction
Up to $134 potential savings per unit annually
In the graph below the unit retrofit with an EC motor is represented by the orange line and the unit with a PSC motor is represented by the blue line.
The chart illustrates the energy consumed by each unit at low and high speeds.
The EC motor operates between .4 amps (off) and increases to .8 amps in use.
The PSC motor operates between 1 amp up to 1.7.
| PSC Motor | EC Motor | % Reduction | |
| High Speed | 1.7 | 0.75 | 53% |
| Low Speed | 1.04 | 0.42 | 60% |
The PSC motor represented by the blue lines produced guest room temperature that varied widely between 54 degrees and 68 degrees.
The unit retrofit with an EC motor represented by the orange lines produced guest room temperature that fluctuated narrowly between 64 degrees to 68 degrees. AirRevive’s room temperature is constant maintaining a comfortable guest room environment.
The data demonstrates that the unit retrofit with an EC motor maintained the guest room temperature within a 4 degree variance while the PSC motor produced guest room temperature that varied between 14 degrees.
Relative humidity below 66% signifies dry air.
The unit retrofit with an EC motor maintained guest room relative humidity at or below 65%.
The PSC motor guest room humidity ranged daily between 65% – 90%. This allowed for high humidity time periods.
The data demonstrates that the EC motor maintained guest room relative humidity within a narrow band while the PSC motor produced relative humidity that fluctuated widely.
These results are to be expected because the EC motor airflow is programmed to the manufacturer’s design specifications. When the air moves across the coil at the correct speed the coil evaporates humidity as designed. The PSC motor relative humidity fluctuated widely because the motor on high speed over-blows, which does not allow for water to be evaporated from the air.
The humidity graph (above left) and the guest room temperature graph (above right) demonstrate that the unit retrofit with an EC motor (orange lines) produced slightly higher guest room temperature within a narrow band while maintaining lower relative humidity.
The PSC motor (blue lines) produced cooler guest room temperature coupled with higher relative humidity. This combination of cool air with high humidity results in an uncomfortable guest room that is often characterized by dank feeling.
These graphs side-by-side clearly demonstrate that the EC motor produced a more comfortable guest room.
Optimal Asset Protection and Odor Prevention
Mold spores begin to grow when humidity hits 66%.
The unit retrofit with an EC motor creates a healthy, dry environment preventing mold spore.
The dry room also prevents A/C related odor spreading and embedding into the room assets.
