Pump power and control requirements

ASHRAE 90.1-2019

G3.1.3.5 Hot-Water Pumps

The baseline building design hot-water pump power shall be 19 W/gpm. The pumping system shall be modeled as primary-only with continuous variable flow and a minimum of 25% of the design flow rate. Hot-water systems serving 120,000 ft2or more shall be modeled with variable-speed drives, and systems serving less than 120,000 ft2 shall be modeled as riding the pump curve.

Exception to G3.1.3.5

The pump power for systems using purchased heat shall be 14 W/gpm.

G3.1.3.10 Chilled-Water Pumps (Systems 7, 8, 11, 12, and 13)

Chilled-water systems shall be modeled as primary/secondary systems with constantflow primary loop and variable-flow secondary loop. For systems with cooling capacity of 300 tons or more, the secondary pump shall be modeled with variable-speed drives and a minimum flow of 25% of the design flow rate. For systems with less than 300 tons cooling capacity, the secondary pump shall be modeled as riding the pump curve. The baseline building constant-volume primary pump power shall be modeled as 9 W/gpm, and the variable-flow secondary pump power shall be modeled as 13 W/gpm at design conditions. For computer room systems using System 11 with an integrated fluid economizer, the baseline building design primary chilled-water pump power shall be increased by 3 W/gpm for flow associated with the fluid economizer.

Exception to G3.1.3.10

For systems using purchased chilled water, the building distribution pump shall be modeled with variable-speed drive, a minimum flow of 25% of the design flow rate, and a pump power of 16 W/gpm.

G3.1.3.11 Heat Rejection (Systems 7, 8, 11, 12, and 13)

The baseline building design condenser-water pump power shall be 19W/gpm and modeled as constant volume. For computer room systems using System 11 with an integrated fluid economizer, the baseline building design condenser water-pump power shall be increased by 3W/gpm for flow associated with the fluid economizer. Each chiller shall be modeled with separate condenser-water and chilled-water pumps interlocked to operate with the associated chiller.

Requirement change:

ASHRAE 90.1-2013 Appendix G:

G3.1.3.5 Hot-Water Pumps:

The baseline building design hot-water pump power shall be 19 W/gpm. The pumping system shall be modeled as primary-only with continuous variable flow. Hot-water systems serving 120,000 ft2 or more shall be modeled with variable-speed drives, and systems serving less than 120,000 ft2 shall be modeled as riding the pump curve.

Exceptions: The pump power for systems using purchased heat shall be 14 W/gpm.

G3.1.3.10 Chilled-Water Pumps (System 7, 8 and 11)

The baseline building design pump power shall be 22 W/gpm. Chilled-water systems with a cooling capacity of 300 tons or more shall be modeled as primary/secondary systems with variable-speed drives on the secondary pumping loop. Chilled-water pumps in systems serving less than 300 tons cooling capacity shall be modeled as a primary/secondary systems with secondary pump riding the pump curve. For computer room systems using System 11 with an integrated water-side economizer, the baseline building design primary chilled-water pump power shall be increased 5 W/gpm for flow associated with the water-side economizer.

Exceptions: The pump power for systems using purchased chilled water shall be 16 W/gpm.

G3.1.3.11 Heat Reject (System 7, 8, 9, 12, and 13)

The baseline building design condenser-water pump power shall be 19 W/gpm. For computer room systems using System 11 with an integrated water-side economizer, the baseline building design condenser water-pump power shall be increased 5 W/gpm for flow associated with the water-side economizer. Each chiller shall be modeled with separate condenser water and chilled-water pumps interlocked to operate with the associated chiller.

ASHRAE 90.1-2016, 2019 Appendix G:

G3.1.3.19: System 5 through 8, The baseline system shall be modeled with a preheat coil controlled to a fixed setpoint 20F less than the design room heating temperature set point.

Key Ruby Methods

Standards.Model.rb

plant_loop_apply_prm_baseline_pump_power()
plant_loop_apply_prm_baseline_pumping_type()

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