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CA Title 24 Requirements for Supermarket Refrigeration

CA Title 24 Requirements for Supermarket Refrigeration. VaCom Technologies Heschong Mahone Group Sept. 22, 2010. Introduction.

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CA Title 24 Requirements for Supermarket Refrigeration

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  1. CA Title 24 Requirements for Supermarket Refrigeration VaCom Technologies Heschong Mahone Group Sept. 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

  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 3 CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes

  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

  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

  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

  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 7 CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes

  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

  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

  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 CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes

  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 CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes

  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

  13. Base Code Measures CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes • 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 CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes

  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 15 CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes

  16. Store and System Types 16 CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes

  17. 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 17 CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes

  18. Direct Emissions Assumptions 18 *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

  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

  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. 20 CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes

  21. 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 21 CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes

  22. Base Case – Large Supermarket 22 Sacramento weather 60,000 SF Air-cooled 24 hour Annual kWh CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes

  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 23 CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes

  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 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. 24 CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes

  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? 25 CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes

  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 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. 26 CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes

  27. Remote Condenser Specific Efficiency Evaporative condenser and fluid cooler standards still being evaluated, but generally offer more flexibility by adjusting fan hp. 27 CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes

  28. Remote Condenser Specific Efficiency 28 CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes

  29. Remote Condenser Specific Efficiency 29 CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes

  30. Remote Condenser Specific Efficiency 30 CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes

  31. Remote Condenser Specific Efficiency 31 CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes

  32. 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. 32 CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes

  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? 33 CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes

  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 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. 34 CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes

  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? 35 CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes

  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. 36 CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes

  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? 37 CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes

  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: 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. 38 CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes

  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. 39 CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes

  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. 40 CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes

  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 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. 41 CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes

  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. 42 CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes

  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. Savings include adjustment for compressor return gas temperature and LT LSHX performance assumes mechanical subcooling as the reference baseline. 43 CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes

  44. 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. 44 CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes

  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. 45 CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes

  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. 46 CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes

  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: CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes

  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: Costs for open cases vary widely (or information is misunderstood). Savings based on 24 hour store. 48 CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes

  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. 49 CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes

  50. Display Case LED Lights 50 CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes

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