Process Air Compressors, Boilers, and Water Heaters #1

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Chilled and Hot Water Temperature Reset Controls Rationale – Hot Water CALIFORNIA STATEWIDE UTILITIES CODES AND STANDARDS PROGRAM 30 ● HW temperature reset always reduces boiler energy and piping losses and always reduces total energy, especially for condensing boilers ● HW temperature reset can increase HW pump energy if the pump has a VFD. (VFDs are not cost effective or required on hot water pumps). Even if the HW pump has a VFD, increasing HW pump energy decreases boiler energy (opposite of CHW pumps!) so HWST reset always makes sense ● Temperature reset is low/no cost – it requres a minor amount of programming but no additional hardware CA 2011 Utilities Title 24 2011 CASE Title Process 24 Stakeholder Update Meeting for Proposed Code Changes May 25, 2010
Chilled and Hot Water Temperature Reset Controls Rationale – Chilled Water CALIFORNIA STATEWIDE UTILITIES CODES AND STANDARDS PROGRAM 31 ● ● ● ● Variable flow is required on most CHW and HW systems VFDs are required on many CHW pumps but not on any HW pumps For CHW systems with VFDs the options are to reset pressure setpoint and/or temperature setpoint ● ● Resetting pressure will always reduce total energy but will not necessarily save as much energy as temperature reset The converse is not necessarily true: resetting temperature could increase total energy in some scenarios. This is why pressure reset is required but temperature reset is not required. For CHW systems without VFDs there is no pressure reset ● ● Resetting the temperature will result in a tiny increase in pump energy for variable flow systems (pump rides out on curve) but will always reduce total energy due to reduced chiller lift The CHW exeption for variable flow was likely a mistake caused by 90.1 language that lumps variable flow and variable speed in the same section CA 2011 Utilities Title 24 2011 CASE Title Process 24 Stakeholder Update Meeting for Proposed Code Changes May 25, 2010
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Page 3 and 4: CALIFORNIA STATEWIDE UTILITIES CODE
Page 5 and 6: Requirements for a Successful Code
Page 17 and 18: WH2 Standby Loss Typical Practice C
Page 27 and 28: 27 Chilled and Hot Water Temperatur
Page 29: CALIFORNIA STATEWIDE UTILITIES CODE
Page 41 and 42: Process Boilers California Nonattai
Page 47 and 48: 47 CALIFORNIA STATEWIDE UTILITIES C
Page 51 and 52: Air Compressors Potential Code Chan
Page 53 and 54: Air Compressors Initial Data / Find
Page 55 and 56: Air Compressors Potential Code Chan
Page 57 and 58: Air Compressors Specific Stakeholde

Process Air Compressors, Boilers, and Water Heaters #1

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