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ASHRAE WILL GIVE
YOU THE WORLD
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Julian R. de Bullet
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deBullet Consulting
SESSION OBJECTIVES
At the end you should be able to:
1. Explain why a mechanical engineer should understand
ASHRAE Standard 90.1-2010
2. Select the appropriate unit efficiency for a project and adjust a
chiller for non-standard conditions
3. Explain when an economizer must be used
4. Describe when reheat is allowed
5. Use the fan system limitation calculation
6. State when heat recovery must be used
ASHRAE 90.1-2010 BECOMES CODE
As a result of DOE’s ruling, and by the
authority provided through the Energy
Conservation and Production Act, as
amended, states are required to certify
by Oct. 18, 2013 that they have reviewed
the provisions of their commercial build-
ing code regarding energy efficiency and
updated their code to meet or exceed
Standard 90.1-2010. States may request
extensions of this deadline from DOE if
a state can demonstrate that it has made
a good faith effort to comply with this
code update.
STANDARDS AND RATING PROGRAMS
Move to High Performance Buildings
ASHRAE 189.1 2010 LEED® 2012
ASHRAE 90.1 2010
LEED® V3 2009
LEED® V2.2 2005
LEED® V2.0 2000
LEED® V1.0 1998
LEED® V2.1 2002
LEED is a registered trademark of the U.S. Green Building Council.
ASHRAE 90.1 1975
ASHRAE 90.1 1980
ASHRAE 90.1 1989
ASHRAE 90.1 1999
ASHRAE 90.1 2004
ASHRAE 90.1 2007ASHRAE 62.1 2007
ASHRAE 62.1 2004
ASHRAE 62.1 1973
ASHRAE 62.1981
ASHRAE 62.1 1989
ASHRAE 62.1 2010
Used as baseline
Codes in Effect
8
Projected Code Adoption Dates
9
ASHRAE 90.1-2007 ASHRAE 90.1-2010
109 Addenda included, 52 affect HVAC
ESTIMATED SAVINGS 2007 TO 2010
11
1. Scope expanded to cover plug and process loads
(data centers)
2. Building envelope more stringent and high albedo roofs
included
3. Interior Lighting Power Densities lowered,
mandatory daylight controls and exterior lighting zones
4. Expanded equipment efficiencies, new energy
recovery requirements, additional control
requirements
5. Expanded energy modeling requirements (LEED)
MAJOR CHANGES IN 90.1-2010
12
LEED is a registered trademark of the U.S. Green Building Council.
To provide minimum energy efficient requirements of
buildings other than low-rise residential for:
1. Design, construction and a
plan for operation & maintenance
2. Utilization of on-site renewable
energy resources
ASHRAE 90.1 PURPOSE- CHANGES
Applies to:
1. New Buildings and systems
2. New portions of buildings or systems
3. System & equipment additions in
existing buildings
4. Covered portions of
manufacturing facilities
Does not apply to:
1. Single family, residential less than
3-story above grade or modular houses
2. Buildings that do not use
electricity or fossil fuel
ASHRAE 90.1 SCOPE
Where required
• Mandatory
‒ These provisions must be met under all circumstances
and performance can not be traded
Example – HVAC equipment efficiency
• Prescriptive
‒ These provisions are met by using the prescriptive
value or using the performance method
Example – Air side economizer
• Energy Cost Budget (Performance)
‒ Allows trade-offs of prescriptive options if the total cost
is equal to or less than the prescriptive option
PATHS TO COMPLIANCE
• Energy Cost Budget Method
‒ Used to determine trade-off
of performance of one feature
against another feature
• Performance Rating Method
‒ Used to determine the
improvement in performance
of proposed versus baseline
building
ECB VS. PRM
Only part which is code intended
ASHRAE 90.1 – 2010 Regulated Sections
Sect. 5.4 & 5.5 Envelope Requirements
Sect. 6.4 & 6.5 HVAC Equipment
Sect. 7.4 & 7.5 Service Water Heating
Sect. 8.4 Power voltage drop
Sect. 9.4 & 9.5 Lighting control and density
Sect. 10.4 Electric Motors
* See WWW.energycodes.gov/implement/determinations_com.stm
PRIMARY SECTIONS
All of Alaska in Zone 7 except for the following
Boroughs in Zone 8:
Bethel Northwest Artic
Dellingham Southeast Fairbanks
Fairbanks N. Star Wade Hampton
Nome Yukon-Koyukuk
North Slope
Zone 1 Includes
Hawaii, Guam,
Puerto Rico,
and the Virgin Islands
Dry Moist (A)Marine (C)
CLIMATE ZONES
Zone 1
2. ASHRAE 90.1 has requirements that do not regulate the
energy use of which of the following?
a) Lighting power density
b) Plug power from computers
c) Task lighting
d) Minimum insulation values for roof
e) Power limit for pumps on an ornamental water garden
f) Maximum amount of ventilation air that can be provided
g) Data centers
h) Plug loads
EXERCISE
SECTION 6 – HVAC
6.7 Submittals
Section 6 Heating, Ventilation and Air Conditioning
6.1 General
6.3 Simplified Approach
6.5 Prescriptive PathSection 11 Energy Cost
Budget Method
6.4 Mandatory Provisions
6.2 Definition of Compliance Paths
1. Process applications added (data centers)
2. Updated efficiency tables and added equipment types
3. Liquid – to – liquid heat exchangers now covered under AHRI 400
4. Restrictions on pump head and pipe sizing
5. VAV requirement for CW and DX single zone units
6. Significant increase in insulation for ducts and pipe
7. Added radiant panel system requirements
8. Changes to airside economizer requirements
9. Changes to damper leakage requirements
10. Changes to reheat / recool minimum use and application
11. Requirement for dynamic ventilation control on VAV requirement from Std 62.1
12. Limit on use of centrifugal fan open towers
13. A climatic based requirement for energy recovery
14. New requirements for garage and kitchen ventilation
15. New requirements for laboratory exhaust
MAJOR CHANGES TO HVAC
1. Building is two stories or less
2. Gross floor area is ≤ 25,000 ft2
3. HVAC system serves one zone
4. Must have single zone VAV capability
5. Cooling system is unitary packaged or split system that meet
the required efficiencies
6. Economizer must be used if required by climate zone
7. Heating must be by heat pump or furnace that meets the
required efficiencies
8. Energy recovery if zone and outdoor air requirement are met
9. Must use a manual changeover thermostat
10. Heat pump lockout of supplementary heater required
SIMPLIFIED APPROACH
Star indicates an important change
11. Reheat and simultaneous heating and cooling is prohibited
even for humidity control
12. Units with motors greater than ¾ hp must have a time clock
with 2-hr override, and provide setback to 55⁰F and set-up to
90⁰F
13. Pipes must be insulated per requirements
14. Duct must be sealed and insulated per requirements
15. Air balance required
16. Multiple units to a space must be interlocked
17. Exhaust in a system over 300 CFM must be equipped with
gravity or motorized damper
18. Systems over 10,000 CFM must have optimum start control
SIMPLIFIED APPROACH (CONTINUED)
3. Which of the following is not a case covered by the scope
of ASHRAE 90.1 2010?
Choose one answer.
a) The area of a building being renovated if it is more that 50%
b) Refrigerant change - out with existing equipment that does
not comply
c) A new building that is heated but not cooled
d) A high rise apartment building where the tenant furnishes
their own AC unit
EXERCISE
Tables6.8.1A – Air Conditioners and Condensing Units
6.8.1B – Heat Pumps
6.8.1C – Water – Chilling Packages
6.8.1D – Packaged Terminal and Room Air Conditioners
6.8.1E – Furnaces, Duct Furnaces, and Unit Heaters
6.8.1F – Boilers
6.8.1G – Heat Rejection Equipment
6.8.1H – Heat Transfer Equipment
6.8.1I – VRF Air Conditioners
6.8.1J – VRF Air-to-Air & Applied Heat Pumps
6.8.1K – Computer Room Units
EQUIPMENT EFFICIENCIES
Air-Cooled Packaged
EQUIPMENT EFFICIENCIES-ALL CHANGED
30% Increase
17% Increase
Note: Both requirements must be met
Water-Cooled Packaged
EQUIPMENT EFFICIENCIES-CHANGES
IMPACT OF ASHRAE 90.1 – 2010-CHANGES
28
Air Conditioner ASHRAE 90.1 -- 2004
Air Conditioner ASHRAE 90.1 -- 2010
Example Unit
EQUIPMENT EFFICIENCIES
CHILLER EFFICIENCIES- CHANGES
tonkWCOP
/
516.3
Conditions:
44F LWT
85F ECWT
3 GPM/ton
Path A –
Normal duty
Path B –
Continuous duty
Assume we have a 750 ton centrifugal chiller that meets
path A requirements
Full load kW/Ton = 0.570 , IPLV = 0.539
Lvg Cond = 91.16 F
Lvg Evap = 42 F
Lift = 91.16 – 42 = 49.16 F
A = 0.0000014592 x (49.16)4 – 0.0000346496 x (49.16)3 +
0.00314196 x (49.16)2 -0.147199 x (49.16) +3.9302
A = 1.0228
B = 0.0015 x 42+ 0.934 = 0.9970
Adj Full Load kW/Ton = 0.570/(1.0228 x 0.9970) = 0.559
NPLV = 0.539 /(1.0228 x 0.9970) = 0.529
EXAMPLE CHILLER AT NON-STANDARD
1. When evaluating if a chiller with lower efficiency
can be substituted for the mandatory requirement of
ASHRAE 90.1 – 2010 for chiller efficiency which
method should be used?
Choose one answer.
a) The Appendix G Performance Rating Method
b) The Section 11 Energy Cost Budget Method
c) The prescriptive requirement from Section 6.4
d) None, since it is a mandatory requirement
EXERCISE
6.4.2.1 Load Calculations
Heating and cooling loads must be calculated
per ANSI / ASHRAE / ACCA Standard 183-2007
Peak Heating and Cooling Calculations in
Buildings Except Low-Rise Residential
6.4.2.2 Pump Head
Pump head must be calculated by the
pressure drop in the critical circuit at design
REQUIRED CALCULATIONS
Ventilation Controls
6.4.3.4.1Stair shafts and elevators must have motorized shut-off
dampers
6.4.3.4.2
1) Outdoor air and exhaust must have automatic
dampers with ability to shutoff during warm-up,
cool-down and unoccupied times
‒ Gravity dampers allowed
• For exhaust and relief if building is ≤ 3 story
• For Intakes in Zones 1,2,3
• System is less than 300 CFM
6.4 MANDATORY REQUIREMENTS
Ventilation Controls
3) Damper leak rate:
Ventilation Exhaust / Relief
Gravity Motorized Gravity Motorized
Zone 4,5b,5c
< 3 Story Not allowed 10% 20% 10%
≥ 3 Story Not allowed 10% Not Allowed 10%
Zone 5a,6,7,8
< 3 Story Not allowed 4% 20% 4%
≥ 3 Story Not allowed 4% Not Allowed 4%
6.4 MANDATORY REQUIREMENTS
Ventilation Controls
6.4.3.4.4
Ventilation fans greater than ¾ hp must have
automatic shutdown capability when not required
6.4.3.4.5
Enclosed parking garages shall be able to modulate
to 50% or less of design airflow if contaminate levels
are maintained
6.4 MANDATORY REQUIREMENTS
6.4.3.5:Heat Pump Auxiliary Heat Control
Supplemental heater must have controls that
prevent operation when the heat pump is capable
of meeting the load during operation and recovery-
heater operation is permitted during defrost
6.4.3.7:Humidification and Dehumidification
System must be able to prevent humidification from
working when dehumidification is active
6.4.3.8:Freeze Protection and Snow Melting Systems
Must be deactivated above 40⁰F
6.4 MANDATORY REQUIREMENTS
6.4.3.9:Ventilation Controls for High Occupancy
High occupancy is > 40 people/1000 ft2
For spaces > than 500 ft2 require DCV if system has:
Airside economizer
Automatic modulating control of outdoor air damper
Airflow > 3000 CFM
Unless:
System exhaust energy recovery (6.5.6.1)
System does not have a DDC system
System outdoor airflow is ≤1,200 CFM
6.4 MANDATORY REQUIREMENTS
6.4.3.10
1. CW AHU or fan coil with motor >5 hp must
have either 2–speed motor or VFD to reduce
airflow at 50% demand or less to either
a) ½ of full speed
b) Airflow required for ventilation per Std 62.1
2. As of 1/1/2012 DX units 110,000 Btuh or more
must have either 2–speed motor or VFD to
reduce airflow at 50% demand or less to
1) ⅔ of full speed
2) Airflow required for ventilation per Std 62.1
SINGLE ZONE VAV CONTROLS
1. All duct above 2” wg. and
upstream of VAV boxes
must be sealed to class A
2. Pressure testing of minimum
of 25% of duct area required
on duct systems over 3” wg.
DUCT SEALING
1. Select 3 mandatory requirements of ASHRAE 90.1 2010
related to HVAC units?
Pick at least three answers.
a) HVAC equipment part load efficiency
b) 20 degree differential in WSHP loop boiler off to cooling tower
on temperature
c) Pumps with over 50 HP must have a VFD
d) Reheat limited to less than 0.4 CFM / ft2
e) Motorized damper leakage at no more than 10 CFM / ft2
f) Optimum start control for systems over 10,000 CFM
g) Dead band of at least 5 F between heating and cooling setpoint
EXERCISE 4
Comfort Cooling (air or water) All zones except 1a and 1b ≥ 54,000 Btu/h
Computer Rooms
Zones 1a, 1b, 2a, 3a, 4a - Not required
Zones 2b, 5a, 6a, 7, 8 ≥ 135,000 Btu/h
Zones 3b, 3c, 4b, 5b, 5c 6b ≥ 65,000 Btu/h
Exceptions:
‒ Non-particulate air treatment required by Std 62.1
‒ Hospitals with >75% space requiring humidification above 35 F dewpoint
‒ Condenser heat recovery is used
‒ Residential spaces
‒ If internal sensible cooling at design is less that transmission at 60F
‒ System operation less that 20 hr / week
‒ Supermarkets when it will impact case
‒ If unit efficiency exceeds 42% better in 4a and 49% better in zone 5a
‒ Computer rooms in some conditions
6.5.1.ECONOMIZER REQUIREMENTS
6.5.1.1 PRESCRIPTIVE REQUIREMENTS
EconomizersAir Economizer
‒ Modulate outdoor air and return air to provide 100%
of supply air quantity – must provide relief
‒ Must be integrated with cooling and can not be controlled
only by mixed air temperature
‒ Relief that prevents recirculation must be provided
High limit cut-off Control
Zone 4a Zone 5a
Fixed Dry Bulb Not Allowed TOA > 70
Differential Dry Bulb Not Allowed TOA > TRA
Fixed Enthalpy hOA > 28 Btu/lb
Electronic Enthalpy (TOA ,RHOA)> A
Differential Enthalpy hOA > hRA
Dew-point and dry-bulb DPOA >55F or TOA > 75F
6.5.1.2 PRESCRIPTIVE REQUIREMENTS
EconomizersWater Economizer
‒ Provide 100% of capacity by indirect evaporative cooling at50⁰F DB and 45⁰F WB
‒ Pressure drop can not exceed 15 ft on primary or use a
secondary loop
‒ Must use integrated economizer
Except:
‒ Some computer room applications
‒ System where dehumidification requirements can not be metat 50⁰F DB and 40⁰F WB
6.5.1.4: All Economizer
Economizer operation can not increase the need for heating
energy at normal conditions
5. A chiller using glycol solution with a freezing point less than 27⁰ F should use which efficiency rating condition?
Select one answer
a) Full load kW / ton
b) Full load COP
c) Part load IPLV
d) None ‒ These are outside the range
e) EER rating
f) IEER rating
EXERCISE 5
6.5.2 PRESCRIPTIVE REQUIREMENTS
Simultaneous Heating and Cooling Limits
Zone controls must prevent:
Reheating
Re-cooling
Mixing of air that has been mechanically heated
or cooled by mechanical cooling or economizer
Other simultaneous operation of heating and cooling
Simultaneous Heating and Cooling Limits
Condition 1
Exceptions where reheat is allowed if the air reheated
is less than the larger of the following:
1. Air is no less than the required
zone ventilation air per Standard 62.1
2. Air is < 30% of peak design airflow
3. If allowed by AHJ when shown that it reduces
total energy
4. Zones requiring pressure differential or
code requirement
AHJ: Authority having jurisdiction
6.5.2 PRESCRIPTIVE REQUIREMENTS
Simultaneous Heating and Cooling Limits
Condition 2
Exceptions where reheat is allowed if the zone meets
all the following:
1. Airflow rate in the dead band between heating and cooling
is not larger than:
1. 20% of the zone peak airflow
2. Required zone ventilation air per Standard 62.1
3. If allowed by AHJ when shown that it reduces total energy
2. Reheat, recooled or mixed air is less than 50% of peak
3. Airflow between dead band and full heating and full cooling
can be modulated
6.5 PRESCRIPTIVE REQUIREMENTS
Simultaneous Heating and Cooling Limits
Condition 3
Exceptions where reheat is allowed if:
1. Laboratory exhaust that meets Section 6.5.7.2
Condition 4
Exceptions where reheat is allowed if:
1. 75% of the reheat energy is
from site recovered energy
or site-solar assisted energy
6.5 PRESCRIPTIVE REQUIREMENTS
6. New energy for reheat is allowed in which 3 of the
following situations?
Select three answers.
a) The airflow has been reduced to the minimum
ventilation air allowed by ASHRAE 62.1
b) Minimum air volume is < than 0.4 CFM/FT2
c) Reheat is only allowed if no new energy is used
d) Reheat is never allowed except in process applications
e) Air being reheated is < 30% of peak design airflow
EXERCISE
Air System Design and Control
Systems over 5 hp total system nameplate must meet the fan hp
limitation based on name plate hp
Fan Power limitation
Supply fans, return fans, relief fans, exhaust fans and fan-powered
terminal units must meet option 1 or option 2
Exceptions:
‒ Hospital and labs where pressure differential must be maintained
can use VAV fan power limit
‒ Individual exhaust fans with motor name plate of 1 hp or less
Motor nameplate can be no larger than the next available motor size
Exceptions:
If bhp is < 6 – motor can be within 50% of bhp
If bhp is ≥ 6 – motor can be within 30% of bhp
6.5 PRESCRIPTIVE REQUIREMENTS
Option 1 ‒ VAV system supplying 25,000 CFM
hp limit = CFMs x 0.0015 = 25,000 x 0.0015 = 37.5 hp
Maximum is then 37.5 Nameplate hp
AHU systems with 30 hp supply and 7.5 hp exhaust
nameplate motors would be acceptable
Option 2 – Same systems full ducted and MERV 13 filters
hp limit = CFM s x 0.0013 + A
A = Pd x CFM / 4131
A duct = 0.5 x 22,000/4131 = 2.66
A MERV 13 = 0.9 x 25,000/4131 = 5.44
hp limit = 25,000 x 0.0013 +2.66 +5.44 = 40.6 bhp
Maximum is then 40.6 bhp
FAN POWER EXAMPLE
52
(Includes series fan power boxes)
‒ All motors 10 hp and larger must:
1. Be driven by a mechanical or electrical variable speed drive
2. Or use a vane-axial or variable pitch fan
3. Or have controls that will reduce motor demand to
30% of design watts at 50% flow
‒ Static pressure sensor must be placed so that the
controller setpoint is no more than 1/3 of total design static
‒ On DDC systems static setpoint must be reset by the
zone with the largest demand
6.5.3.2 VAV FAN POWER LIMITS
53
Multiple zone systems must (6.5.3.3):
• Provide reset control of supply air in response to load
or outdoor air temperature
‒ Must be capable of resetting 25% of the
difference between supply air and room setpoint
‒ Reset based on humidity is allowed
‒ Equipment rooms (data centers) must be able to fully reset
Except:
‒ Zones 1a, 2a and 3a
‒ Systems that prevent reheating, re-cooling or mixing
‒ Systems with 75% reheat energy from site recovered
or site solar
SUPPLY AIR TEMPERATURE RESET
54
7. ASHRAE 90.1 has a prescriptive requirement which limits
the fan power energy. Which of these statements is true?
Select one answer
a) The calculation only applies to the power at part load
conditions of VAV units using a variable frequency drive
b) A correction factor is applied when filters with a MERV
rating greater than MERV 8 are used
c) The calculation of fan power applies to supply, return,
and exhaust fans but not the fans in VAV fan powered
terminals.
d) The power calculation must be based on the nameplate
rating of the motor only
EXERCISE
Hydronic System Control
‒ Systems with pumps 10 hp and larger and control valves must be
capable of reduction to 50% design flow
‒ Pumps over 5 hp must have the ability to reduce to
30% power at 50% flow
‒ Controls shall function to maintain minimal pressure differential
and drive the valve with the greatest demand full open
‒ Differential pressure should be no more that required for
110% of heat exchanger flow
Exceptions:
‒ Flow less than manufactures minimum where pump hp is
75 hp or less
‒ System has no more than 3 control valves
6.5.4 PRESCRIPTIVE REQUIREMENTS
Hydronic System Control
‒ Pumps on systems with more than one chiller must have
isolation of the used chiller (6.5.4.2)
‒ Chilled and hot water in systems > 30,000 Btu/h must reset
chilled and hot water temperature based return water
temperature or outdoor temperature (6.5.4.3)
Except:
‒ When control reset will cause improper operation
of heating, cooling, humidifying or dehumidification
‒ Hydronic systems using variable flow pumping
‒ Hydronic loops must use two-position isolation valves to stop
water flow when the compressor is off applies to WSHP and
unitary water cooled units
6.5 PRESCRIPTIVE REQUIREMENTS
6.5.6 PRESCRIPTIVE REQUIREMENTS
Energy Recovery
Exhaust air energy recovery is required if:
Exhaust Air Heat
Recovery
8. Heat recovery is required by ASHRAE 9.1 2010 under
certain conditions. Which requirements are true?
Select one answer.
a) In zone 5a the airflow is 5500 CFM and 30% is outside air
b) The energy effectiveness is less than 50%
c) An economizer is not required if an ERV with a thermal
effectiveness of 50% or better is used
d) Energy recovery is required if 75% of the lab hood are not
controlled by a demand control ventilation or schedule
EXERCISE
Hot Gas Bypass Limitation
Cooling systems can not use
hot gas bypass or evaporator pressure
control unless multiple steps of capacity
are provided and maximum hot gas
is limited to:
≤ 240,000 Btu/h 50% maximum
> 240,000 Btu/h 25% maximum
Exception:
Unitary systems less than 90,000 Btu/h
This includes screw and centrifugal machines and is based on the
system size IE: 100 ton machine can not bypass more than 25 tons
6.5.9 PRESCRIPTIVE REQUIREMENTS
• One or more pressure sensors shall be used to vary the
pump speed and/or start and stop the pumps.
• No device shall be installed for the purpose of reducing
the pressure of all of the water supplied by any booster
system pump or booster system, except for safety
devices.
• No booster system pumps shall operate when there is no
service water flow
Conclusion
Every booster pump system will be variable flow
10.4.2 Service Water Booster Systems
61
Performance Rating MethodDemonstrate a percentage improvement above the baseline building
Note:
Based on energy costs
Must meet 90.1 mandatory requirements
Must include all project energy costs
Baseline building must comply with
Appendix G requirements
Process energy requirements
Appendix G is for modeling improvedperformance not tradeoff calculations
ASHRAE 90.1 NORMATIVE APPENDIX G
THANK YOU!
63
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