5.3102.33 Optimize Variable Frequency Drive Control

Hydronic Heating (Hot Water and Steam)
Equipment Installation
Desired Outcome: 
Varied distribution loop flow to minimize pumping energy
Verify proper placement, type, and condition of sensors

Sensor location, type, and condition will be assessed in accordance with selected control strategy

Determine condition and presence of existing sensors for variable frequency drive (VFD) operation

Install, repair, relocate, or replace sensors as necessary

Sensors will be installed or replaced in accordance with manufacturer specifications and as required for selected control strategy

Ensure required sensors are properly located and functioning for VFD operation

Initial setup of VFD

VFD parameters will be set up to accept feedback from sensors dependent upon chosen control strategy and to maintain minimum boiler and pump flows

Set initial parameters to maintain minimum system pumping requirements with reduced electrical energy use

Modify operating set points based on observed system performance

Accurate supply and return temperatures will be obtained and compared to design distribution loop temperature differential on representative mild, cold, and design temperature days

Settings will be adjusted to maintain design distribution loop differential temperature on representative mild, cold, and design temperature days

Minimum distribution loop water temperature requirement will be maintained

Minimum boiler and pump flow rates will be maintained

Ensure optimal settings based on actual operating conditions to limit system from over pumping and to reduce the pump energy consumption while protecting the pump and boiler

Record and report settings

Observed supply, return, and outdoor temperatures and all control set points on representative mild, cold, and design temperature days will be documented and provided to building operations staff

Ensure written record of settings

Educate building operations staff

Building operations staff will be educated to operate VFD systems, including sensor location, control operation, and set points

Ensure continued optimized performance