Energy Efficiency Reference/Refrigeration/Recommendations/Install ASD on Evaporator Fans
Recommendation: Install ASD on Evaporator Fans
[edit | edit source]Summary: Convert fan motors to adjustable speed drives (ASD's) on air-cooled evaporators to reduce part-load fan power.
When to apply: When single-speed or two-speed fan motors demand a lot of power.
Key Engineering Concepts:
- Ideally, fan power is cubically related to fan capacity with a variable speed motor
- Fan power is linearly related to capacity with on-off fan control
- Fan capacity is proportional to the condensing approach temperature difference
Preparation:
Tools required
- DMM or power analyzer
- Clamp-on Ammeter
- Stopwatch
- Thermometer
- Refrigeration Data Sheets
Data Sheet
- Suction Temperature (ST)- from pressure gauge or compressor display
- Total fan power (FP) - measured
- Dry bulb temperature - measured
- Evaporator approach temperature difference (DT, approximately 10 degree F) - measured
- Fan cycling schedule, if any.
Analysis Process: ?????