Our free energy-saving class series for business customers, co-sponsored by Energy Trust of Oregon and the Northwest Energy Efficiency Alliance, continued in February with a class on Ammonia Refrigeration. Here are some key lessons from this information-packed seminar:

• It’s often possible to lower the minimum compressor head pressure to 100 psi or below, which will save energy.
• A screw compressor with a slide valve delivers poor part-load efficiency. Instead, consider using a variable frequency drive (VFD) to save energy.
• In many applications, evaporator fans equipped with VFDs run at 60 percent speed, but they use less than 30 percent of the energy of a fan without a VFD!
• Condenser fan VFDs coupled with outside air temperature and humidity measurement can be used to optimally balance compressor and condenser energy use.
• Try cautiously raising the suction pressure to save energy while assuring that your space or process temperature is maintained.
• A refrigeration control system can orchestrate your entire system, using all the best energy strategies. It can also provide you with a comprehensive picture of the entire system, beyond just energy performance.

If you were unable to attend this class and have questions about your ammonia refrigeration system, contact your PGE representative.