CA Title 24 Requirements for
Supermarket Refrigeration
VaCom Technologies
Heschong Mahone Group
Sept. 22, 2010
09/22/2010
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
2
Introduction
● California Energy Commission (CEC) and California
Air Resources Board (CARB) are working together
on the next round of the state’s building energy
efficiency code (2011 Title 24)
● This is the first time that Title 24 is dealing with
direct GHG emissions
● CARB team (ICF International) is addressing
emissions (direct and indirect) and leak reduction
● For CEC, IOU team (HMG/VaCom) is addressing
energy savings – the focus of this meeting
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
3
3
IOU Support for 2011 Title 24
● The California Investor Owned Utilities (IOUs) are
actively supporting the California Energy
Commission (CEC) in developing the state’s
building energy efficiency code (Title 24)
● Their joint intent is to achieve significant energy
savings through the development of
reasonable, responsible, and cost-effective code
change proposals for the 2011 code update and
beyond
● As part of the IOU effort, at the request of the CEC,
we are hosting stakeholder meetings to get
industry input and feedback on our code change
proposals
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
4
Code Change Activity
● 2011 T-24 Base Code (Part 6 of Title 24)
● 2011 Reach Standard (Part 11 of Title 24)
● Green Building Standard – i.e. CalGreen
● Two levels of efficiency:
●
Tier I
15% beyond the Base Code
●
Tier II
30% beyond the Base Code
● Future Codes
● 2014 T-24
● Future Reach Standards
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
5
Requirements for a Successful Base Code
● To be included in the base code, a measure must:
●
Be cost-effective
●
●
●
based on the standards-induced additional first cost,
maintenance costs, measure life, and energy cost
savings
typically according to the CEC Time Dependent
Valuation (TDV) life-cycle costing methodology and
weather data
Be possible to implement using equipment that
is available from multiple providers or that is
reasonably expected to be available following
the code change
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
6
Purpose of Reach Code
● Easily adopted, standardized approach for
jurisdictions wishing to implement a more stringent
code than Title 24
● Basis for awarding incentives for utilities or other
entities seeking to promote more efficient building
techniques
● Present a framework to introduce and test energy
efficiency measures that are not yet ready for
adoption in the Base Code
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
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7
Stakeholder Meetings Process
● Minimum of three meetings:
●
●
●
First: present scope, request data
●
Code change direction and possible options
●
Methodology
●
Best practices, market data
Second: present findings
●
Results of energy analysis
●
Preliminary cost effectiveness
Third/final: present proposed code language
● All meetings can be attended remotely
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
8
Submitting Comments
● Informal Comment Process
● Comments can be submitted to CASE authors,
substantive comments will receive responses
● The team will work with stakeholders to resolve
issues as best we can
● Questions and responses will not be posted online,
but common or frequent questions will be
communicated as necessary between stakeholders
● The CEC has a formal comment process during
later stages of the official rulemaking process
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
9
Types of Code Change
● Mandatory Measure:
● Mandatory measures must be satisfied whether
the prescriptive or performance method is used
to show compliance
● Prescriptive Requirement:
● When there is not a performance compliance
(computer modeling), prescriptive requirements
are essentially mandatory requirements
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
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Types of Code Change –
Ctd.
● Performance Requirement:
● Computer modeling
● Prescriptive requirements are used to define a
standard design to set the energy budget
● No performance option is being proposed
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
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Schedule: Key Dates
● Mar 2010 - Dec 2010
●
●
CEC develop foundation /methodology
IOUs:
●
●
Conduct research, and cost effectiveness analysis
Present results at stakeholder meetings
● Jan 2011
●
IOUs finalize code change proposals for submittal to CEC
● Feb 2011
●
CEC opens Rulemaking for Title 24, develop 45-day
language
● June 15, 2011
●
Title 24 Adoption date
● Jan. 1, 2013
●
Title 24 Implementation date
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
12
Meeting Protocols
● Please DO NOT place your phone on HOLD
● Please mute your microphone, unless you want to
speak
● Ask questions/comment by “chat” or by voice
● We want to hear your concerns
●
●
Opposing viewpoints are encouraged
We are seeking information, not resolution
● Time is limited
●
●
●
Raise your hand and be acknowledged by presenter
Clearly state your name and affiliation prior to speaking
Speak loudly for the people on the phone
● Minutes and presentation material will be available
online – we will distribute link
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
13
Base Code Measures
● Floating head pressure
●
Floating head pressure control with variable speed fan
control, variable setpoint logic
● Remote condenser specific efficiency
●
Maximum condenser fan power per unit of capacity; aircooled and evap-cooled
● Floating suction pressure
●
Setpoint control strategy
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
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Base Code Measures (contd)
● Mechanical subcooling
●
Low temp subcooling from medium temp system or
economizer on LT scrolls, screws
● Evaporator coil specific efficiency
●
Maximum evaporator fan power per unit of cooling
capacity: freezer, cooler; low-profile, medium-profile
● Evaporator coil variable speed control
●
Primary temperature control (central systems); off-cycle
reduced speed (single systems)
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
15
Base Code Measures (contd)
● Liquid-suction heat exchangers
●
Display cases
●
Walk-in evaporator coils
● Display case LED lights
●
Reach-in glass door cases
● Display case lighting control
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
16
Store and System Types
Store and Refrigeration System Combinations
Small
Supermarket
10,000 SF
Air-Cooled
Condenser
Evap-Cooled
Condenser
Fluid Cooler
Large
Supermarket
60,000 SF
Air-Cooled
Condenser
Evap-Cooled
Condenser
Fluid Cooler
Big Box
Food Store
150,000 SF
Air-Cooled
Condenser
Evap-Cooled
Condenser
Fluid Cooler
Central
Distributed
Central
Central
Distributed
Central
Distributed
Central
Central
Distributed
Central
Distributed
Central
Central
Distributed
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
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GHG Emissions
● Low Charge Systems
●
Secondary loop & distributed systems modeled
● Direct GHG Emissions
●
Offline analysis based on annual refrigerant losses & GWP-weighting
●
MTCO2e results will be considered with energy analysis
● Leak Reduction Measures
●
Mandatory measures developed with industry input; reflect basic good
practices without imposing cost burden
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
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Direct Emissions Assumptions
Base Case System
Configuration
Centralized
Distributed
Secondary
Loop
Refrigerant Type
R-404A, R-507
R-404A, R-507
R-404A &
glycol/ CO2
Small Supermarket
(210,420 BTU)
610
490
135
Large Supermarket
(713,750 BTU)
2,075
1,660
460
Big Box Food Store
(1,100,042 BTU)
3,200
2,560
710
18%
15%
10%
15% - 25%
10% - 15%
5% - 15%
Charge Size (lbs)*
Leak Rate (percent of charge per year)
Average
Range (of averages)
*Charge calculated for each refrigeration system type based on average pounds per BTU;
estimated primarily based on available literature with consideration given to supermarket data,
supermarket drawings, and manufacturer/user input.
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
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Direct Emissions
● EE measures that impact charge size:
Energy Efficiency Measure*
Change in Charge Size
Relative to Baseline
Floating head pressure control
Increase
Heat reclaim
Increase
Remote condenser specific efficiency
Increase
*Measures not listed are not assumed to impact charge size
● Impact of specific measures on charge size
will be quantified based on input from
equipment manufacturers and installers
09/22/2010
20
Analysis Methods
● DOE 2.2R whole building hourly simulation
● Fixtures loads disaggregated, balance space
interactions (fixture, HVAC, building, etc.)
● Mass-flow/component based refrigeration system
modeling, explicit control strategies
● Modeling of building envelope, HVAC, lighting,
skylights, etc.
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
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Base Case Assumptions
● Title 24 compliant building
●
Insulation, lighting power density, HVAC systems
●
Minimum skylights and light level control
● Display cases
●
T-8 lights, EC motors, low watt glass door heaters
● Walk-ins
●
Federal Walk-in standard compliant
● Refrigeration systems
●
Partial floating head pressure, fixed suction, no subcooling
● Schedules: operations, occupancy, lighting, etc.
● Project information: www.calcodesgroup.com
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
22
Base Case – Large Supermarket
Sacramento weather
60,000 SF
Air-cooled
24 hour
Annual kWh
Display
Cases
Lights
Compressors
702,657
168,641
248,755
76,230
30,335
423,398
239,203
1,889,219
37%
9%
13%
4%
2%
22%
13%
100%
Misc Loads
Walk In
Fans
Condensers
Lights
Misc Loads
HVAC
Condensers
Walk In Fans
Compressors
Display Cases
Total:
HVAC
Refrigeration
769,166 41%
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
23
Cost Effectiveness
● Title 24 cost-effectiveness analysis
●
●
●
Time dependent valuation method
Life-cycle cost consideration including energy,
maintenance and measure life
Statewide evaluation in multiple climate zones
● Preliminary economics (this presentation)
●
Single climate zone (Sacramento)
●
Large supermarket simulation model
●
Simple savings valuation ($.12/kWh)
●
Estimated maintenance
●
Simple payback
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
24
Floating Head Pressure
●
Condenser controls to allow head pressure to float with ambient
conditions to a minimum SCT of 70 F or lower, using ambientfollowing (TD) setpoint control and variable speed control of all fans
in unison. Results for large supermarket, air-cooled condensers:
Savings (kWh)
Savings ($)
Measure Cost ($)
Maintenance Cost ($)
Simple Payback
54,157
$6,499
$13,600
$1,600
2.8
●
Savings adjustment of 30% to allow for typical sensor error and
control system variations vs. hourly simulation results.
●
Annual maintenance cost allows for cost of setpoint verification
and/or periodic recommissioning of controls.
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
25
Floating Head Pressure
● Variable speed may be accomplished using a variable speed
drive or EC condenser fan motors with variable speed control
signal.
● Applies to air-cooled, evap-cooled and fluid coolers.
● Savings are subject to setpoint increase or override, but many
chains have demonstrated ability to maintain setpoints over
time.
● Code exceptions:
●
●
●
Allow fixed setpoint on evap-cooled condensers due to low reliability of
RH sensors?
Allow for strategies that are equal or better than ambient-following, if
“equal or better than” can be defined?
Exception on a remodel/expansion if condenser is not being replaced?
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
26
Remote Condenser Specific Efficiency
●
Minimum specific efficiency (BTU/Hr per watt) for air cooled
condensers of 70 BTUh/W, calculated at 10 F TD. Maximum fin
spacing of 10 FPI.
Savings (kWh)
Savings ($)
Measure Cost ($)
Maintenance Cost ($)
Simple Payback
10,942
$1,313
$8,800
$0
6.7
●
Savings are compared vs. a reference baseline with floating head
pressure and variable speed fan control (previous measure).
●
Savings compared with 50 BTU/W, which is the average of
condensers installed in recent years, which were below 70 BTUh/W.
●
Cost based on going from 50 to 90 BTUh/W since a compliant model
would be an available model better than 70 BTUh/W.
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
27
Remote Condenser Specific Efficiency
● Evaporative condenser and fluid cooler standards
still being evaluated, but generally offer more
flexibility by adjusting fan hp.
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
28
Remote Condenser Specific Efficiency
Manufacturer A
$120
Cost ($/MBH)
$100
$80
$60
y = 0.2106x + 36.041
R² = 0.8277
$40
$20
$0
0
20
40
60
80
100
120
140
160
Specific Efficiency (Btuh/Watt)
EC Motors
1.5 HP 1140 RPM
1.5 HP 830 RPM
1 HP 830 RPM
0.5 HP 540 RPM
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
29
Remote Condenser Specific Efficiency
Manufacturer C
$70
$60
Cost ($/MBH)
$50
$40
$30
y = 0.0144x + 34.281
R² = 0.0029
$20
$10
$0
0
20
40
60
80
100
120
140
160
Specific Efficiency (Btuh/Watt)
0.5 HP, 575 RPM
1 HP 850 RPM
1 HP 850 RPM
1.5 HP 1140 RPM
1.5 HP 1140 RPM
1.5 HP 850 RPM
1.5 HP 850 RPM
1.75 HP 1050 RPM EC
1.75 HP 1050 RPM EC
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
30
Remote Condenser Specific Efficiency
Manufacturer D
$80
$70
Cost ($/MBH)
$60
$50
$40
$30
y = 0.1562x + 27.194
R² = 0.15
$20
$10
$0
0
20
40
60
80
100
120
Specific Efficiency (Btuh/Watt)
0.5 HP 550 RPM
1 HP 850 RPM
2 HP 1140 RPM
0.75 HP 1075 RPM
EC Motors
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
31
Remote Condenser Specific Efficiency
Manufacturer E
$60
Cost ($/MBH)
$50
$40
y = 0.1405x + 28.881
R² = 0.8813
$30
$20
$10
$0
0
20
40
60
80
100
120
140
160
180
Specific Efficiency (Btuh/Watt)
0.33 HP 550 RPM
1.5 HP 1140 RPM
1 HP 850 RPM
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
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Remote Condenser Specific Efficiency
● Discussion:
●
●
●
Very large range of specific efficiencies appears to make this an obvious
efficiency measure.
Necessary to establish maximum fin density (proposed at 10 FPI), which
is generally consistent with chain specifications and contractor practice
for supermarkets.
However, new condensers models with EC motors are among the lowest
specific efficiencies; using higher HP motors and kW input than previous
models with induction motors. EC motors possibly have option to be
applied with higher specific efficiency by limiting maximum speed.
● Test and rating standards and certification:
●
●
Condensers ratings do not reference standards and are not certified.
Standard will be difficult without standards and certification, particularly
with EC condensers having lowest specific efficiencies and highest cost.
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
33
Remote Condenser Specific Efficiency
● Code exceptions:
●
Combination air-evaporative condensers.
●
Remodel/expansion if condenser is not being replaced?
●
Small systems with design heat of rejection less than 150,000 BTU/Hr.
●
Micro-channel condensers exempt from fin spacing?
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
34
Floating Suction Pressure
●
Controls on compressor systems to allow suction pressure to float
based on fixture and/or walk-in box temperature setpoint rather
than fixed suction pressure control. Other temperature controls on
selected “float” system(s) must be secondary to floating suction
control.
Savings (kWh)
Savings ($)
Measure Cost ($)
Maintenance Cost ($)
Simple Payback
16,433
$1,972
$2,400
$600
1.7
●
Savings includes 40% reduction to allow for imperfect control system
operation compared with simulation results.
●
Annual maintenance cost allows for cost of setpoint verification
and/or periodic recommissioning of controls.
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
35
Floating Suction Pressure
● Applies to multiple compressor systems and variable capacity
single compressors satellite systems on racks.
● Most chains have included floating suction pressure for many
years, but results vary.
● Savings depend on effort applied to system design, fine-
tuning during start-up and ongoing maintenance. Electronic
suction regulators require greater control sophistication.
● Code exceptions:
●
Single compressor systems with on-off control.
●
Remodel/expansion if compressor system is not being replaced?
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
36
Mechanical Subcooling
● Liquid subcooling to 50 F or lower at design SCT on all low
temperature compressor systems through use of a subcooling
heat exchanger connected to a medium temperature
refrigeration system or connected to the economized port on
a low temperature compressor designed to include
economizer subcooling.
● Applies to multiple compressor systems and variable capacity
single compressors satellite systems on racks.
Savings (kWh)
Savings ($)
Measure Cost ($)
Maintenance Cost ($)
Simple Payback
18,252
$2,190
$5,900
$300
3.1
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
37
Mechanical Subcooling
● Savings allows for 5 F temperature rise from subcooler to
refrigerated loads, plus 20% reduction in savings to allow for
control variations vs. simulation results.
● Mechanical subcooling has been in common use by most
chains for decades, and has greater savings with HFC
refrigerants than with HCFC-22. Cost is minimal for the
mandatory configuration in that net compressor horsepower
of a central rack system decreases.
● Code exceptions:
●
Single compressor systems.
●
Low temperature systems using direct CO2 refrigerant.
●
Low temperature systems with a design SCT of 70 F or below.
●
Remodel/expansion if compressor system is not being replaced?
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
38
Evaporator Coil Specific Efficiency
●
Proposed measure to require minimum specific efficiency (BTU/Hr
per watt) for evaporator coils. Savings opportunity appeared large
due to wide range of specific efficiency, but:
●
Example of three coil models in one product line, all with two fans:
Specific
Capacity Fan Watts Efficiency
9,000
7,500
6,500
●
118
118
118
76
64
55
CFM
1,300
1,300
1,400
Airside TD
6.4
5.3
4.3
Findings:
●
●
Airflow (i.e. airside temperature difference) is a variable in product lines,
causing much of the observed range in specific efficiency.
Eliminating inefficient models could often cause selection of larger
models with increased cost and no reduction in fan power.
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
39
Evaporator Coil Specific Efficiency
●
Manufacturers could produce more efficient models through
redesign with different fan blades and/or motors rather than using
“excess air” and other modifications.
●
Test and rating standards and certification:
●
●
Evaporator ratings do not reference standards and are not certified.
●
Standard will be difficult without standards and certification.
Conclusions:
●
●
Additional study including lab testing is required before rules can be
adopted.
Test and ratings standards and certification would be required since
product lines would require redesign. Field measurement is not feasible.
● Priority vs. variable speed control:
●
Use of variable speed control would reduce the potential savings from
higher specific efficiency and vice-versa. Variable speed is more easily
implemented than a specific efficiency standard.
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
40
Evaporator Coil Variable Speed Control
●
Variable speed control of walk-in evaporator fans as the primary
means of temperature control in freezers and coolers Requirements
also apply to indirect cooling coils, e.g. glycol and CO2. Other
temperature controls, including suction regulator valves, on-off
liquid solenoids and floating suction control would not act until
variable speed control is at minimum speed.
●
Low and medium profile evaporator coils use EC motors (with limited
exceptions on larger coils) and offer potential of simple, low-cost
inherent speed control.
●
Applies to multiple compressor systems and variable capacity single
compressors satellite systems on racks.
●
Evaporators connected to single compressor systems would be
required to use reduced speed (i.e. two speed) or fan duty-cycling
during the compressor off-cycle period.
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
41
Evaporator Coil Variable Speed Control
●
Savings assumes a minimum speed of 70%.
●
Simulation included forced speed increases, plus an additional 20%
reduction in savings was allowed to address typical control system
variations.
Savings (kWh)
Savings ($)
Measure Cost ($)
Maintenance Cost ($)
Simple Payback
18,966
$2,276
$9,600
$800
6.5
●
Savings for medium profile coils (e.g. large point-of-sale boxes) yet
to be evaluated, and are expected to have shorter payback.
●
Cost is a rough estimate, since pricing has not yet been obtained
from manufacturers. Additional research in progress.
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
42
Evaporator Coil Variable Speed Control
●
Current availability:
●
Low profile evaporator coils: 1-2 manufacturers
●
Medium profile coils: 2-3 manufacturers
●
Uncertain how control would be provided: could be through the
“rack” controller to integrate suction regulators and floating suction
pressure, or using a distributed controller.
●
Code exceptions:
●
●
Evaporators for single compressor systems; use two-speed or duty-cycle.
Exception on a remodel/expansion if evaporator coils and associated
refrigeration system is not being replaced, since speed control must be
coordinated with suction circuit and rack controls.
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
43
Liquid-Suction Heat Exchangers
●
Proposed requirement for liquid-suction heat exchangers on direct
expansion display cases line-ups and walk-ins, to provide 17°F of
subcooling on LT systems at 55°F entering liquid temperature, and 7°
F of subcooling on MT systems at 75°F entering liquid temperature.
MT Cases
Savings (kWh)
Savings ($)
Measure Cost ($)
Maintenance Cost ($)
Simple Payback
●
MT Walk-Ins
LT Cases
14,768
$1,772
$2,600
$0
1.5
LT Walk-Ins
4,768
$572
$1,000
$0
1.7
Savings include adjustment for compressor return gas temperature
and LT LSHX performance assumes mechanical subcooling as the
reference baseline.
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
44
Liquid-Suction Heat Exchangers
Tout (Liquid)
Tin (Liquid)
Tin (Vapor)
Tout (Vapor)
●
Increases system capacity by providing liquid subcooling.
●
Less non-productive suction line cooling, including un-evaporated
liquid out of cases. Allows tighter superheat settings.
●
Helps maintain stability with floating head pressure by subcooling to
avoid flash gas at expansion valve.
●
May become a no-cost option when impact on capacity if fully
understood.
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
45
Liquid-Suction Heat Exchangers
●
Savings assumes properly operating superheat controls, which likely
understates the savings achieved by minimizing overfeeding of
liquid, particularly on close-approach medium temperature display
cases.
●
The increased use of refrigerants with high glide (e.g. 407x) will
realize a greater value from liquid-suction heat exchangers.
●
Code exceptions:
●
Primary refrigeration systems on indirect system (due to wider range of
possible refrigerants and system types)
●
Display cases or evaporators with design SST higher than 30 F.
●
Systems using direct CO2 refrigerant.
●
Low temperature systems with a design SCT of 70 F or below.
●
Remodel/expansion if display case line-up or walk-in evaporator is not
being replaced.
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
46
Liquid-Suction Heat Exchangers
● Requirement for display cases anticipates a LSHX for each
case line-up. Individual heat exchangers within each case is
possible as well, although the liquid line heat loss within the
case piping may defeat the purpose or require insulation.
Since leaving refrigerant conditions are not defined in the
Federal display case requirements, a LSHX could be used by
the display case manufacturer to achieve the Federal standard
for the individual display case. Many display cases use a
nominally sized LSHX or solder the liquid and suction lines
together. The code requirement for degrees of subcooling
would be total for published subcooling included in the
display case (if any) and the display case line-up LSHX.
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
47
Display Case LED Lights
● Proposed requirement for LED lights in display fixtures in
reach-in glass door freezers and coolers, including factory
made display cases and field-installed doors for point-of-sale
walk-ins.
● LED lights in reach-in freezer cases in common use. Reach-in
coolers and doors for point-of-sale freezer and cooler walkins also readily applied.
● Results for low temperature reach-in doors:
Savings (kWh)
Savings ($)
Measure Cost ($)
Maintenance Cost ($)
Simple Payback
78,123
$9,375
$22,000
$0
2.3
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
48
Display Case LED Lights
● LED options for medium temperature display cases have far
greater variations and appear to be still in development (color
issues).
● Results for medium temperature upright open cases:
Savings (kWh)
Savings ($)
Measure Cost ($)
Maintenance Cost ($)
Simple Payback
28,365
$3,404
$25,500
$0
7.5
● Costs for open cases vary widely (or information is
misunderstood).
● Savings based on 24 hour store.
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
49
Display Case LED Lights
● Code exceptions:
●
●
Exception on a remodel/expansion if existing display cases or
walk-in point-of-sale doors are being reused.
Question on used fixtures purchased used or relocated from
another store. Some retrofits are being done in existing stores,
indicating economics may justify upgrading used cases. More
research required.
● Timing consideration: LED technology is advancing rapidly.
Effective date for 2011 Title 24 Standard is January 1, 2013.
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
50
Display Case LED Lights
20
10
0
Reach-in T-8 W/Door Reach-in LED W/Door
Canopy T-8 Canopy
W/f t
LED W/f t
3.5
4.5
5.3
5.4
2.2
3.0
23.0
30
27.0
40
27.6
50
4.1
60
6.9
70
10
9
8
7
6
5
4
3
2
1
0
7.2
7.4
7.0
69.6
72.0
80
79.9
90
9.2
T-8 and LED Watts per Row
by Manufacturer
T-8 and LED Watts per Door
by Manufacturer
Shelf T-8
W/f t
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
Shelf LED
W/f t
09/22/2010
51
Display Case Lighting Controls
● Proposed requirement for automatic controls to turn off
display case lights on non-24 hour stores.
Savings (kWh)
Savings ($)
Measure Cost ($)
Maintenance Cost ($)
Simple Payback
82,349
$9,882
$4,000
$100
0.4
● Includes 20% reduction in savings vs. simulation results to
allow for overrides and improper settings.
● Code exceptions:
●
Allow timed override switches with a minimum of two zones to allow
lights to operate for case stocking during non-business hours.
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
52
No Open Upright Freezers
● Proposed rule to prohibit use of open upright
freezer cases.
● No recent stores (based on Savings By Design
experience) use open upright freezer cases.
● Additional analysis in progress.
● Discussion: are there reasons to allow use of open
upright freezer cases for certain applications?
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
53
Reach Codes
● Optional codes for:
●
Jurisdictions
●
Program requirement
● Basis for next round of code updates
● Two levels of efficiency:
●
Tier I
15% beyond the Base Code
●
Tier II
30% beyond the Base Code
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
54
Demand Defrost (Reach Code)
●
Evaluation of possible prohibition of gas defrost and required use of
demand defrost controls in conjunction with electric defrost and
trunk piping.
●
Purpose of energy evaluation is to determine the increased energy
with this measure vs. the benefit of reduced HFC leakage.
Electric Defrost kWh
Savings (kWh)
Savings ($)
Measure Cost ($)
Maintenance Cost ($)
Simple Payback
29,691
12,145
$1,457
$12,900
$1,000
28.2
●
Analysis assumes 60% reduction in defrost frequency and improved
defrost efficiency at each defrost (since more ice is accumulated).
●
No credit is taken yet for lower RGT with trunk piping.
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
55
Demand Defrost (Reach Code)
● Demand defrost controls have been used in the
past but are not currently in use in supermarkets.
Availability is limited.
● The potential requirement of electric defrost (or
prohibiting gas defrost) should be evaluated vs.
fixed-time electric defrost control.
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
56
Heat Reclaim for Space Heating (Reach Code)
● Proposed requirement for heat recovery from refrigeration to
provide at least 25% of the design refrigeration heat of
rejection for space heating, while increasing the refrigerant
charge by no greater than 20% or 0.50 lbs per 1,000 BTU/Hr
of heating capacity, whichever is less.
● Analysis for a full heat recovery system in an large
supermarket using Sacramento weather:
Savings (Net) ($)
Measure Cost ($)
Maintenance Cost ($)
Simple Payback
$8,329
$30,000
$1,000
4.1
● Code exceptions:
●
Remodel/expansion when compressor system is not being replaced.
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
57
No Open Upright Cooler Cases (Reach Code)
● Possible future Reach Code to require glass doors
on all open upright cooler cases.
● Detailed study is required to determine energy
savings, as well as understand the impacts on store
design, operations, and other factors. Additional
analysis to being considered.
● Discussion: what factors need to be considered in
addition to energy analysis?
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010
58
Next Steps
● Refinement of measure list
● Measure life-cycle cost effectiveness analysis
CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes
09/22/2010