ASHRAE Standard 90.1-2010 made significant improvements in energy efficiency over the 2004 version. It expanded the scope to include process loads and established new requirements in key areas like building envelopes, HVAC systems, and lighting. The standard evaluates savings based on both site energy and energy cost reductions. Compliance can be met through prescriptive requirements or through a trade-off option. The presentation reviewed many of the changes introduced in key sections between the 2007 and 2010 versions.

1. ASHRAE Standard 90.1-
2010
Hugh Crowther P. Eng
Director at Large

2. Agenda
• ASHRAE Standards
Development
– Jargon
• Std 90.1 layout
• Review of changes to
each section
• How Improvements
are evaluated
• Questions

3. Compliance Approaches
Building Systems Compliance Options
Envelope Prescriptive
Option
HVAC
Trade Off
SHW Option
Mandatory Compliance
Provisions
Power
Energy Cost
Budget
Lighting
Simplified
Other

4. Std 90.1 Sections
• Section 1: Purpose • Section 7: Service Water Heating
• Section 2: Scope • Section 8: Power
• Section 3: Definitions • Section 9: Lighting
• Section 4: Admin and • Section 10: Other Equipment
Enforcement • Section 11: Energy Cost Budget
• Section 5: Building Envelope (ECB) method
• Section 12: Normative References
• Appendices

5. Std 90.1 -2010
• Significant Savings
over 2004 version
• Site energy savings is National With Without
in kWh Weighted Receptacle Receptacle
Energy Loads Loads
• Site energy cost Savings
savings is in $
Site 25.5% 32.6%
– Std 90.1 evaluates itself Energy
on energy cost
Energy 24.0% 30.1%
• How did they do that? Cost

6. How did they do that?
30% Improvement
109 Addenda
TPS Change
2004 2007 2010
Lets talk about changes from 2007 version to the 2010 version

7. Section 2
Change in Scope
• Process (plug) loads
can now be included 11%
17% Lighting 17%
• The TPS change Cooling 9%
allows the committee Heating 21% 64%
14%
to write rules on plug 9%
Ventilation 5% Regulated
loads if they deem it Water Heating 9%
Refrigeration 3%
necessary 3%
Electronics 5%
• If the Std does not 3%
Computers 3% 25%
specifically address a 5% Cooking 3% Unregulated
21% Other 14%
process load, then it 3%
Adjust to SEDS 11%
is unregulated 9%
5%
A 30% total site reduction would require a 47% reduction in regulated loads
A 50% total site reduction would require a 78% reduction in regulated loads
Source: Building Energy Data Book 2009, Table 3.1.4

8. Section 5
Building Envelope
• Building envelope
requirements change
based on location
• Approximately 20
changes between
2007 and 2010
versions
• Informative Appendix
F lists changes by
addenda

9. Section 5
Building Envelope
• Continuous air barrier
for most buildings
– 5.4.3.1
– Material leakage rate
under 0.004 cfm/ft² @
0.3 in. w.c.
– Assembly leakage rate
under 0.04 cfm/ft² @ 0.3
in. w.c.
Goal: Minimize infiltration by 83% and
HVAC energy usage by 40% - NIST

10. Section 5
Building Envelope
• Tightened air leakage
rates for fenestration
and doors
– 5.4.3.2
– 1 cfm/ft² @ 1.57 PSF for
doors
– 0.06 cfm/ft² @ 1.57 PSF
for curtain wall
Goal: Minimize infiltration

11. Section 5
Building Envelope
• Vestibule
Requirements
changed
– 5.4.3.4
• Insulation
requirements for
metal buildings more
stringent
– 5.5.3.1 and 5.5.3.2

12. Section 5
Building Envelope
• Cool roofs required in
some climate zones
– 5.5.3.1.1
– Zones 1,2 and3
– Solar reflectance = 0.55
– SRI = 64 (ASTM E1980)
Goal: Minimize roof loads

13. Section 5
Building Envelope
• Vertical fenestration must
have more area on south
side than on either east
or west side
– 5.5.4.5
• Large spaces with tall
ceilings must have
minimum skylight area
and automatic daylighting
controls
– 5.5.4.2.3

14. Section 5
Building Envelope
• Exceptions are
provided to SHGC
requirements for
dynamic glazing
– 5.5.4.4.1

15. Section 6
HVAC Systems
• Process cooling can now be
included
– Scope change
• New data center requirements
– Added CRAC units based on ASHRAE
Std 127
– Introduced sensible Coefficient of
Performance (SCOP)
– 6.4.1.1, 6.5.1, Table 6.8.1k
– A/C equipment primarily serving
computer rooms must meet Table
Example of process loads now being
6.8.1k
considered

16. Section 6
HVAC Systems
• Upgraded efficiencies
to most HVAC
equipment categories
– 6.8.1 tables
• New term for Unitary
equipment
– Integrated Energy
Efficiency Ratio (IEER)
– Brings focus to part load
efficiency rather than just
full load performance Goal: Promote Part load performance

17. Section 6
HVAC Systems
• Increased efficiency for water-
cooled and evaporatively cooled
air conditioners/heatpumps
– 3 to 5% more stringent as of June 2011
– IEER increase from 5 to 13%
– Two position valves required on water
cooled unitary equipment (WSHPs)
– Pumps larger than 5 hp serving W/C
unitary equipment need VFD

18. Section 6
HVAC Systems
• Water to water heat pumps
– Added to standard
– Efficiencies based on application
(Watersource, ground water, ground
source)

19. Section 6
HVAC Systems
• Increased efficiency for PTACs
and PTHPs as of Oct 2012
– Created standard (16 x 42 size) and non
standard efficiency tables
– Standard size for new construction
Standard
– Non standard size for replacement
(existing wall sleeves)
Non -standard

20. Section 6
HVAC Systems
• Two path compliance for
chillers (addendum M)
– Both paths have a full and part
load target
– Path A targets high full load
performance
– Path B targets high part load
performance
– Chillers with glycol now under
Std 90.1
– Glycol chiller performance
criteria based on just water
when checking with 90.1 Goal: Promote full operating range
performance

21. Section 6
HVAC Systems
• Recent Chiller Interpretations
– Where customers request more
strict conditions than required in
AHRI 550/590, the chillers will be
compared to Std 90.1 at standard
rating conditions.
– Power usage shall be measured at
the line side of starter or VFD.
– Starter and VFD losses must be
included in chiller performance

22. Section 6
HVAC Systems
• Chiller scope expansion
– Air and water cooled positive
displacement chillers now included
in Std 90.1 with LFT > 32 °F
• Non standard chiller equation
– 6.4.1.2.1
– Covers chillers with LFT ≥ 36 °F
– Covers chillers with CWT ≤ 115 °F
– 20 °F to 80 °F of lift
Goal: Avoid gaming by picking 85.1 °F CWT
• About 98% of centrifugal
chillers now covered by Std
90.1

23. Section 6
HVAC Systems
• VRF systems added
– Based on new AHRI 1230 test
standard
– The IEER levels will increase
in 2012
• New rating system for
water to water HX
– 6.4.1.4
– Encouraging manufacturers
to certify their products
– No performance targets yet

24. Section 6
HVAC Systems
• Restrictions on pump
head sizing and pipe
sizing
– 6.4.2.2
– Need to calculate the
pressure drop through
piping and components
for critical path
• Pipe sizing as per
table 6.5.4.5
Goal: Make sure pumps are not oversized
– Flow rate by Dia. And
hours operation

25. Section 6
HVAC Systems
• Pump differential
pressure flow control
shall
– Not exceed pressure
required for 110% of
design flow through heat
exchanger
– Shall reset down during
part load until one
control valve is nearly
open.
– 6.5.4.1

26. Section 6
HVAC Systems
• Hydronic systems
other than unitary
systems must have
VFD over 10 hp
– 6.5.4.1
– No caveats any more
– No pump curve riding etc
Goal: Promote Variable flow systems

27. Section 6
HVAC Systems
• VAV requirement for DX and
chilled water systems that
serve single zone
– 6.4.3.10
– Chilled water systems ≥ 5 hp fan
motors must be variable flow
– 2 spd or VFD
– As of Jan. 1, 2012 DX systems >
110kBtu/h must be able to reduce
fan speed 2/3 or less at 50% load
– 2 spd or VFD
• Fan power ratings based on
constant volume power limits
Goal: Promote fan power savings

28. Section 6
HVAC Systems
• Increased insulation
requirements for
pipes and ducts
– 6.4.4
• New requirements for
radiant panel systems
– 6.4.4
– Ineffective panel areas
shall have r-3.5

29. Section 6
HVAC Systems
• Limitations on centrifugal
fan cooling towers
– 6.5.5.3
– 1100 gpm or greater, must meet
axial fan efficiency
– 38.2 USgpm per fan hp
– Exempt if they are ducted
• New tower category for
closed circuit cooling towers
– Avoid confusion with Fluid
coolers
Goal: Promote fan power savings

30. Section 6
HVAC Systems
• Economizer changes
– 6.5.1
• With more stringent
envelopes and higher
internals loads,
cooling required at
lower ambients
– Promotes economizers
• Economically justified
in all but Zones 1a Goal: Promote economizers. The
and ab. improvements in building envelopes make
economizers economically justified in more
climate zones

31. Section 6
HVAC Systems
• Sizes 54 kBtu/h and larger
require economizers
– Individual unit (not system)
– Air or water economizers
– Economizer is 1st stage cooling
– 2nd stage mechanical cooling
– Economizer goes to minimum
when high limit reached
– High limit settings by region
• 12 exceptions

32. Section 6
HVAC Systems
• Economizer exception for
computer rooms
– 6.5.1j
– Total design below 3,000
kBtu/h and not served by
chiller plant
– Total design below 600 kBtu/h
and is served by chiller plant
– Local authority prohibits
cooling towers
– Less than 600 kBtu/h computer
load being added to existing
building

33. Section 6
HVAC Systems
• Water economizer sizing
for computer rooms
– 6.5.1.2
– Load must be met at 40 °F db/
35°F wb with evaporative type
water economizers
– Load must be met at 35 °F db
with dry type water
economizers

34. Section 6
HVAC Systems
• Changes to damper
leakage requirements
– 6.5.1.1.4
– Comply with changes to
controls section
– Motorized intake and
exhaust dampers in most
climate zones
Goal: Limit infiltration during off hours and slow down heat up or
cool down

35. Section 6
HVAC Systems
• Dynamic ventilation
control for multi zone
VAV systems
following Std 62.1
Appendix A
– 6.5.3.3
– VAV systems with DDC
controls shall lower
ventilation air below
design rate in response
to ventilation efficiency

36. Section 6
HVAC Systems
• Supply air reset
– Removed from 1999
version
– Back in 2010 version
– 6.5.3.4
• Goal is to reset SAT up
to max level when
boxes at minimum flow
– Fan penalty should be
offset by reheat savings Goal: Mechanical cooling savings that more
than offset additional fan work
– Can be based on outdoor
air reset

37. Section 6
HVAC Systems
• SAT Reset exceptions
– Climate zones 1a, 2a,3a
– Systems that prevent
reheating, re-cooling or
mixing
– Systems where 75% of
reheat comes from recovery
or solar.

38. Section 6
HVAC Systems
• Additional requirements
for reheat/re-cool
minimums
– 20% zone design peak supply
rate during deadband and
50% zone peak design rate for
full heating
– Meant to help with
stratification in heating from
ceiling diffusers
• Overheat heating SAT Goal: Reduce heating air flow to minimum
limited to 20 ° above
F level where overhead distribution is still
effective
temperature set point

39. Section 6
HVAC Systems
• Climatic based
requirement for energy
recovery
– 6.5.6
– Based on climate zone, size
and % outdoor air
• New requirements for
garage and kitchen hood
ventilation
– 6.4.3.4.5 and 6.5.7
– Garage systems shall
modulate to 50% based on
contaminants Goal: Fan power savings in garages and
kitchen exhaust systems

40. Section 6
HVAC Systems
• New requirements for
lab exhaust
– 6.5.7.2
– Need to be VAV above
5000 cfm

41. Section 7
Service Water Heating
• No changes from
2007 version

42. Section 8
Power
• Half of all convenience
power outlets shall be
controlled such that power
is turned off when space is
not occupied
– 8.4.2
• Efficiency requirements
added for dry type
transformers
– 8.1.2
– Reflect 2005 Federal
requirements Goal: Std 90.1 in line with Federal codes

43. Section 9
Lighting
• Increased documentation
requirements
– 9.7
• Lighting alteration
requirements now
– Take effect at 10%
replacement
– Include exterior areas
– Include renovations even
when it is just lamp/ballast
replacement
– Require compliance with auto
shut requirements
– 9.1.2

44. Section 9
Lighting
• Changes to lighting
power density (LPD)
values
– tables 9.5.1 and 9.6.1
• Adjustment Factor added
for tall spaces
– 9.6.3
• Additional LPD allowed
when using certain non
mandatory controls
– 9.6.2c

45. Section 9
Lighting
• Allowances for retail
lighting have been
reduced
– 9.6.2b
• Multi-use spaces now
use multiple LPD
valves
– 9.6.1

46. Section 9
Lighting
• Exterior lighting now
broken into 5 zones
based on ambient
light levels
– 9.6.1
– Undeveloped park area
to high traffic
commercial zone

47. Section 9
Lighting
• Light control changes include
(9.4)
– Bi level control
– Auto shut off based on occupancy
required in more spaces
– Certain required controls must be
manual/auto on to no more than
50% power
– Deleted 5000 ft² threshold for auto
shutoff
– Functional testing of some lighting
controls now required (9.4.4)
– Daylight harvesting required in
certain situations 5.5.4.2.3

48. Section 10
Other Equipment
• Control requirements
for water pressure
booster pump
systems
– 10.4.2
– Variable flow design
– Don’t dead head a pump
Goal: Avoid pump work during low or no
flow requirement periods

49. Section 10
Other Equipment
• Requirements added
to limit lighting and
fan power in elevator
cabs and de-energize
during stand by mode
– 10.4.3
• Motor efficiency
tables changed for
motors built after
12/19/2010
– Table 10.8a,b,c
Goal: Keep Std 90.1 in line with Federal
motor requirements

50. Section 11
ECB Method
Large Office
• No changes to 2010
version
• Case sample
provided in previous
Users manual has Secondary School
been deleted
– Can be downloaded
from ASHRAE

51. Appendix G
Performance Rating Method
• Can use Appendix G to rate High-rise Apartment
buildings for other than
compliance with Std 90.1
– LEED
– Appendix G is nota compliance
path
• A building complies with Std
90.1 (section 11) if the
proposed design energy cost ≤
energy cost budget
Hospital
• In Appendix G Proposed
building performance ≥
baseline building performance

52. Appendix G
Performance Rating Method
• Now normative part of the High-rise Apartment
Standard whereas it was
informative
• Heated only storage
spaces have been added
– G3.1.1
• 2 rules added to
ventilation rules for Hospital
baseline HVAC systems
– G3.1.2.6

53. Questions?