HVAC: New chiller requirementsASHRAE Standard 90.1 Addendum ch

Sponsored by:

Jason Gerke, PE, LEED AP BD+C, CxAGRAEF,Milwaukee, WI.

J. Patrick Banse, PE, LEED AP,Smith Seckman Reid Inc.,Houston, TX.

Moderator: Jack Smith, Consulting-Specifying Engineer, CFE Media, LLC

Presenters:

Jason Gerke, PE, LEED AP BD+C, CxAGRAEF

Milwaukee, WI.

J. Patrick Banse, PE, LEED AP,Smith Seckman Reid Inc.

Houston, TX.

ASHRAE Standard 90.1 Addendum ch

HVAC: New chiller requirements

ASHRAE Standard 90.1-2010

• Provides minimum requirements for building and system efficiencies

• Written in code-enforceable language and has been adopted by various authorities having jurisdiction

• “Specifies reasonable design

practices and technologies…”

What is Addendum ch?

Three main topics:• Increase the efficiency of chillers, while

aligning requirements for various chiller types• AHRI has updated 550/590 standard for rating

chillers, and these changes are referenced• High-lift/heat reclaim chillers are excluded.

What is Addendum ch?

Increase the efficiency of chillers• Efficiencies have been increased

approximately 23.1% compared to ASHRAE Standard 90.1-2004 and 8.3% compared to ASHRAE Standard 90.1-2010

• Water-cooled positive-displacement chillers are now required to meet the same efficiencies as water-cooled centrifugal chillers

• Air-cooled chillers are now allowed to follow compliance methodology in Path B

What is Addendum ch?

• AHRI has updated 550/590 standard for rating chillers

• High-lift/heat reclaim chillers are excluded Where temperature of water leaving

condenser exceeds 115 F This temperature is really an arbitrary value

and attempts to exclude chillers that will be operating in high lift applications.

Compliance with 90.1 and Addendum ch

• Energy code/compliance forms, such as COMcheck that require compliance with various aspects of 90.1 depending on project components

• When reading the requirements, determine which portions are relevant to the project type

• Select the path• Select the equipment• Verify compliance.

Why two paths?

• Design/selection flexibility• Path A: FL value, IPLV value

- Based primarily on standard conditions- Can be adjusted for nonstandard conditions

• Path B: FL value, IPLV value Added for part load intensive operation Notice difference in values from Path A

• When there is a Path B, use either A or B, but do not mix values.

Standard conditions/definitions

• AHRI Standard 550/590• Efficiency: performance at specified rating

conditions• IPLV: integrated part load value• NPLV: nonstandard part load value• Nonstandard conditions: any design condition

other than standard.

AHRI standard conditions

• 44 F leaving chilled fluid temp and 2.4 gpm/ton evaporator fluid flow

• 85 F entering condenser fluid temp with 3.0 gpm/ton condenser fluid flow.

Table 6.8.1C

• Replaced previous table• Includes both previous and revised values• Shows both Path A and B values• Added Path B to air cooled chillers• Added two capacity levels to water cooled

centrifugal chillers• Revised kW/ton to full load (FL).

Addendum ch calculations

• Changes to terms Full load to FL, NPLV to PLV

• Formulas remained the same• Units (kW/ton) remained the same• For chillers at standard AHRI conditions: no

calculations needed• For chillers at nonstandard conditions: FL

and IPLV kW/ton must be calculated and adjusted.

Calculations (nonstandard conditions)

• FLadj = FL/Kadj

• PLVadj = IPLV/Kadj

• Kadj = A x B• Where FL = full load kW/ton from Table 6.8.1C• FLadj = max full load kW/ton adjusted• IPLV = IPLV kW/ton from Table 6.8.1C• PLV = maximum NPLV rating adjusted• LIFT = Lvg full load condenser fluid temp minus

Lvg evaporator full load fluid temp.

Calculations (nonstandard conditions)

• A = 0.00000014592 x (LIFT)ⁿ - 0.000034696 x (LIFT)³ + 0.00314196 x (LIFT)² - 0.147199 x (LIFT) + 3.9302 (where n = 4)

• B = 0.0015 x Lvg Evap temp + 0.934

Note: Be careful of truncation and rounding as values will change.

Calculation notes

The FLadj and PLVadj values are only applicable

when all of the following conditions are met:• Min evaporator leaving temp: 36 F• Max condenser leaving temp: 115 F• LIFT is greater than or equal to 20 F and less

than or equal to 80 F.

Example calculation

• A 900 ton water cooled centrifugal chiller using Path A

• FL = 0.560 kW/ton• IPLV = 0.500 kW/ton• Lvg condenser = 96.00 F• Lvg evaporator = 42.00 F• LIFT = 96.00 – 42.00 = 54.00 F• Kadj = A x B.

Example calculation (continued)

• A = 0.93576• B = 0.9970• Kadj = A x B = 0.932953• FLadj = 0.560/(0.93576 x 0.9970) = 0.600245

kW/ton• PLVadj = 0.500/0.932953 = 0.536 kW/ton.

Adjusted value comparison

• Table 6.8.1C values = 0.560 kW/ton FL 0.500 kW/ton IPLV

• Adjusted values = FL = 0.600 kW/ton (7.1% increase) PLV = 0.536 kW/ton (7.2% increase).

Air-cooled chillers and Addendum ch

• What will manufacturers do differently to comply with increased efficiency requirements?

• What do engineers need to consider when selecting air-cooled chillers in compliance with this addendum?

Air-cooled chillers and Addendum ch

ASHRAE 90.1 - 2010 required:

• <150 TR = 9.562 FL / 12.500 IPLV

01/01/15 requires:

>10.100 FL / 13.700 IPLV (Path A)

>9.700 FL / 15.800 IPLV (Path B)

• >150 TR = 9.562 FL / 12.750 IPLV

01/01/15 requires:

>10.100 FL / 14.000 IPLV (Path A)

>9.700 FL / 16.100 IPLV (Path B).

System balancing

• ASHRAE 90.1-2010, paragraph 6.7.2.3: Construction document requirements Written test and balance report Factory chiller test to AHRI standards or

project nonstandard requirements O&M manuals to owner (6.7.2.2).

System commissioning

• ASHRAE 90.1 requires HVAC control systems to be tested

• Applies to projects larger than 50,000 sq ft• Purpose is to “ensure that control elements

are calibrated, adjusted, and in proper working condition.”

System efficiencies

• ASHRAE 90.1 goal: continued decrease in energy use of building HVAC system operation

• Addendum ch goal: continued decrease in energy use (increased efficiency) of water chilling package at full load and part load

• ASHRAE 90.1-2010 weighted average of ≈16.2% in chiller energy use over 90.1-2004

• Addendum ch extends the savings by ≈8.3% over 90.1-2010.

Summary: How to select a chiller to meet 90.1-2010 in 2015

• Review Addendum ch• Decide chiller type and capacity• Choose a Path (A or B)• Choose standard or nonstandard AHRI conditions• Recalculate efficiencies as needed• Have manufacturers verify their products can meet your

nonstandard requirements• Remind chiller manufacturer to label chiller according to your

design criteria in compliance with 90.1 requirements (6.4.1.2.1 and 6.4.1.5)

• Work with chiller manufacturer to determine best solution without being proprietary.

Summary: Addendum ch changes

• Remember to be aware of changes to ASHRAE 90.1-2010 that take effect on January 1, 2015

• How will this change how you are making selections?

• How will manufacturers respond?• How will this affect equipment operation?

Summary: Addendum ch changes

• The following equipment and characteristics should be carefully selected after Addendum ch is adopted:– Air-cooled chillers– High-lift/heat reclaim chillers– Efficiency requirements– Positive displacement chillers– AHRI standards 550/590 and 551/591.

References• Addendum ch• AHRI• ASHRAE Standard 90.1-2010• ASHRAE 90.1 User’s Manual• COMcheck• U.S. Dept. of Energy ANSI/ASHRAE/IES Standa

rd 90.1-2010 Final Qualitative Determination (2011), Pacific Northwest National Laboratory

Jason Gerke, PE, LEED AP BD+C, CxAGRAEF,Milwaukee, WI.

J. Patrick Banse, PE, LEED AP,Smith Seckman Reid Inc.,Houston, TX.

Moderator: Jack Smith, Consulting-Specifying Engineer, CFE Media, LLC

Presenters:

Thanks to today’s Webcast Sponsors:

Research and resources

• Article: Selecting chillers, chilled water systems• Research:

2013 HVAC & Building Automation Systems Study

• More on chillers and boilers

HVAC: New chiller requirementsASHRAE Standard 90.1 Addendum ch

Sponsored by: