ca title 24 requirements for supermarket refrigeration

CA Title 24 Requirements for Supermarket Refrigeration

VaCom TechnologiesHeschong 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

09/22/2010CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes

33

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


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


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


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


77

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


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


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


10

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


11

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


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


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; air-

cooled and evap-cooled

● Floating suction pressure● Setpoint control strategy


14

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)

14


1515

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


1616

Store and System Types


CentralDistributed

Evap-Cooled Condenser

Central

CentralDistributed

CentralDistributed


Central

CentralDistributed

CentralDistributed


Central

CentralDistributed

Big Box Food Store 150,000 SF

Air-Cooled Condenser

Fluid Cooler

Store and Refrigeration System Combinations

Small Supermarket

10,000 SF


Fluid Cooler

Large Supermarket

60,000 SF


Fluid Cooler

1717

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


1818

Direct Emissions Assumptions

Base Case System Configuration

Centralized DistributedSecondary

Loop

Refrigerant Type R-404A, R-507 R-404A, R-507R-404A &

glycol/ CO2

Charge Size (lbs)*

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

Leak Rate (percent of charge per year)

Average 18% 15% 10%

Range (of averages) 15% - 25% 10% - 15% 5% - 15%

*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.


19

Direct Emissions

● EE measures that impact charge size:

*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

Energy Efficiency Measure*Change in Charge Size Relative to

Baseline

Floating head pressure control IncreaseHeat reclaim IncreaseRemote condenser specific efficiency Increase

09/22/2010

2020

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.


2121

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


2222

Base Case – Large Supermarket

Lights 702,657 37%Misc Loads 168,641 9%HVAC 248,755 13%Condensers 76,230 4%Walk In Fans 30,335 2%Compressors 423,398 22%Display Cases 239,203 13%

Total: 1,889,219 100%

Refrigeration 769,166 41%

Lights

Misc Loads

HVACCondensers

Walk In Fans

Compressors

Display Cases


Sacramento weather60,000 SFAir-cooled

24 hourAnnual kWh

2323

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


2424

Floating Head Pressure● Condenser controls to allow head pressure to float with ambient

conditions to a minimum SCT of 70 F or lower, using ambient-following (TD) setpoint control and variable speed control of all fans in unison. Results for large supermarket, air-cooled condensers:

● 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.


Savings (kWh) 54,157Savings ($) $6,499

Measure Cost ($) $13,600 Maintenance Cost ($) $1,600

Simple Payback 2.8

2525

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?


2626

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 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.



Measure Cost ($) $8,800 Maintenance Cost ($) $0

Simple Payback 6.7

2727

Remote Condenser Specific Efficiency● Evaporative condenser and fluid cooler standards

still being evaluated, but generally offer more flexibility by adjusting fan hp.


2828

Remote Condenser Specific Efficiency

y = 0.2106x + 36.041R² = 0.8277

$0

$20

$40

$60

$80

$100

$120

0 20 40 60 80 100 120 140 160

Co

st (

$/M

BH

)

Specific Efficiency (Btuh/Watt)

Manufacturer A

EC Motors 1.5 HP 1140 RPM 1.5 HP 830 RPM 1 HP 830 RPM 0.5 HP 540 RPM


2929


y = 0.0144x + 34.281R² = 0.0029

$0

$10

$20

$30

$40

$50

$60

$70

0 20 40 60 80 100 120 140 160

Cost

($/M

BH

)

Specific Efficiency (Btuh/ Watt)

Manufacturer C

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


3030


y = 0.1562x + 27.194R² = 0.15

$0

$10

$20

$30

$40

$50

$60

$70

$80

0 20 40 60 80 100 120

Cost

($/M

BH

)

Specific Efficiency (Btuh/ Watt)

Manufacturer D

0.5 HP 550 RPM 1 HP 850 RPM 2 HP 1140 RPM 0.75 HP 1075 RPM EC Motors


3131


y = 0.1405x + 28.881R² = 0.8813

$0

$10

$20

$30

$40

$50

$60

0 20 40 60 80 100 120 140 160 180

Co

st

($/M

BH

)

Specific Efficiency (Btuh/Watt)

Manufacturer E

0.33 HP 550 RPM 1.5 HP 1140 RPM 1 HP 850 RPM


3232

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.


3333

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?


3434

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 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.




Simple Payback 1.7

3535

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?


3636

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.




Simple Payback 3.1

3737

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?


3838

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:

● 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.

Capacity Fan WattsSpecific

Efficiency CFM Airside TD

9,000 118 76 1,300 6.4

7,500 118 64 1,300 5.3

6,500 118 55 1,400 4.3


3939

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.


4040

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.


4141

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 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.




Simple Payback 6.5

4242

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.


4343

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.

● Savings include adjustment for compressor return gas temperature and LT LSHX performance assumes mechanical subcooling as the reference baseline.


MT Cases MT Walk-Ins LT Cases LT Walk-InsSavings (kWh) 14,768 4,768

Savings ($) $1,772 $572Measure Cost ($) $2,600 $1,000

Maintenance Cost ($) $0 $0 Simple Payback 1.5 1.7

4444

Liquid-Suction Heat Exchangers

● 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.

Tout (Liquid) Tin (Liquid)

Tin (Vapor) Tout (Vapor)


4545

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.


4646

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.


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 walk-ins also readily applied.

● Results for low temperature reach-in doors:




Simple Payback 2.3

4848

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:

● Costs for open cases vary widely (or information is misunderstood).

● Savings based on 24 hour store.




Simple Payback 7.5

4949

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.


5050

Display Case LED Lights


79.9

27.6

72.0

27.0

69.6

23.0

0

10

20

30

40

50

60

70

80

90

Reach-in T-8 W/Door Reach-in LED W/Door

T-8 and LED Watts per Door by Manufacturer

7.2

6.9

5.4

3.5

7.4

4.1

9.2

4.5

7.0

3.0

5.3

2.2

0

1

2

3

4

5

6

7

8

9

10

Canopy T-8 W/f t

Canopy LED W/f t

Shelf T-8 W/f t

Shelf LED W/f t

T-8 and LED Watts per Row by Manufacturer

5151

Display Case Lighting Controls● Proposed requirement for automatic controls to turn off

display case lights on non-24 hour stores.

● 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.




Simple Payback 0.4

5252

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?


5353

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


5454

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.

● 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.


Electric Defrost kWh 29,691Savings (kWh) 12,145

Savings ($) $1,457Measure Cost ($) $12,900

Maintenance Cost ($) $1,000 Simple Payback 28.2

5555

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.


5656

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:

● Code exceptions: ● Remodel/expansion when compressor system is not being replaced.


Savings (Net) ($) $8,329Measure Cost ($) $30,000

Maintenance Cost ($) $1,000 Simple Payback 4.1

5757

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?


5858

Next Steps

● Refinement of measure list

● Measure life-cycle cost effectiveness analysis


ca title 24 requirements for supermarket refrigeration

Documents

energy efficiency code

code update

stringent code

ca title

meeting09222010ca utilities

code change activity2011

base code09222010ca

base code future codes2014