Nonresidential HVAC Stakeholder Meeting #3

Transcription

1 1 Nonresidential HVAC Stakeholder Meeting #3 California Statewide Utility Codes and Standards Program PECI April 8, 2011

2 HVAC Controls & Economizing Summary of Code Change Proposals 2 1. Revise the prescriptive baseline for economizers from 75,000 Btu/h to 54,000 Btu/h to match ASHRAE A thermostat with two stages of cooling is required for single zone systems whenever an outside air economizer is present 3. Mandatory performance features for economizers 4. Multipurpose rooms of less than 1000 square feet, and classrooms and conference rooms of any size, shall be equipped with occupant sensor(s) to setup/setdown the cooling/heating temperature set points 5. Fault Detection and Diagnostics (FDD) is included in 2008 Title 24 as a compliance option. A proposal is to advance FDD as a prescriptive baseline

3 Code Change Proposal 1 3 Economizer on smaller AC along with compliant t-stats (2-stage or electronic) 2008 Title 24 75,000 Btu/h 2013 Title 24 54,000 Btu/h ASHRAE ASHRAE 189, IECC ,000 Btu/h 33,000 Btu/h

4 Code Change Proposal 1 4 SECTION 144 PRESCRIPTIVE REQUIREMENTS FOR SPACE CONDITIONING SYSTEMS 144 (e) Economizers. 1. Each individual cooling fan system that has a design supply capacity over 1,800 cfm and a total mechanical cooling capacity over 54,000 Btu/hr shall include either: A. An air economizer capable of modulating outside-air and return-air dampers to supply 100 percent of the design supply air quantity as outsideair; or B. A water economizer capable of providing 100 percent of the expected system cooling load as calculated in accordance with a method approved by the Commission, at outside air temperatures of 50 F dry-bulb/45 F wet-bulb and below.

5 Data / Findings 5 Cost effective per T24 methodology Cost effective to 50,000 Btu/h per analysis w/alternating integration and CA TDV costs AHRI: we recommend that you harmonize with ASHRAE 90.1 where a detailed economic analysis and review was done. 54,000 Btu/h matches ASHRAE

6 Cost Effectiveness 6 LCCA for 54,000 Btu/h HVAC system Incremental Installed Cost $786 PV of Maintenance $307 Total Incremental Cost $1,093 PV of Energy Savings $1,182 Lifecycle cost savings $89 Benefit/Cost Ratio 1.1

7 Code Change Proposal (e) Economizers. 2. If an economizer is installed, it shall be: B. Capable of providing partial cooling even when additional mechanical cooling is required to meet the remainder of the cooling load. i. Unitary systems with an economizer shall have control systems, including two-stage or electronic thermostats, that cycle compressors off when economizers can provide partial cooling.

8 Code Change Proposal 2 8 SECTION 149 ADDITIONS, ALTERATIONS, AND REPAIRS TO EXISTING BUILDINGS THAT WILL BE NONRESIDENTIAL, HIGH-RISE RESIDENTIAL, AND HOTEL/MOTEL OCCUPANCIES AND TO EXISTING OUTDOOR LIGHTING FOR THESE OCCUPANCIES AND TO INTERNALLY AND EXTERNALLY ILLUMINATED SIGNS Section 149(b)1E E. When a space conditioning system is altered by the installation or replacement of space conditioning equipment (including replacement of the air handler, outdoor condensing unit of a split system air conditioner or heat pump, cooling or heating coil, or the furnace heat exchanger); 1. Existing non-setback thermostats shall be replaced with setback thermostats for all altered units. All newly installed space conditioning systems requiring a thermostat shall be equipped with a setback thermostat. All setback thermostats shall meet the requirements of Section 112(c); and 2. Unitary systems with an economizer shall have control systems, including twostage or electronic thermostats, that cycle compressors off when economizers can provide partial cooling; and

9 Cost Effectiveness 9 LCCA performed on per t-stat/zone basis Incremental Installed Cost $122 Incremental Annual Maintenance $0 Total Incremental Cost $122 PV of Energy Savings $1,556 Lifecycle cost savings $1,434 Benefit/Cost Ratio 12.8

10 Code Change Proposal 3 10 Economizer performance features: Air economizers and return air dampers on an individual cooling fan system that has a design supply capacity over 1,500 cfm and a total mechanical cooling capacity over 45,000 Btu/hr shall have the following features: Warrantee. 5-year performance warranty of economizer assembly Drive mechanism. Economizer and return dampers have a direct drive modulating actuator with gear driven interconnections Damper reliability testing. Economizer and return damper certified that representative products have been tested and are able to open against the rated airflow and pressure of the system after 100,000 damper opening and closing cycles. Damper leakage. Economizer and return dampers shall be certified to have a maximum leakage rate of 10 cfm/sf at 1.0 in. w.g. when tested in accordance with AMCA Standard 500.

11 HVAC Controls & Economizing Code Change Proposal 3 (cont ) 11 Adjustable setpoint. If the high-limit control is fixed dry-bulb,or fixed enthalpy it shall have an adjustable or selectable setpoint Damper control sensor location. Primary damper control temperature sensor located after the cooling coil to maintain comfort Sensor accuracy. Outdoor air, return air and supply air sensors are calibrated within the following accuracies. Drybulb and wetbulb temperatures accurate to 1 F Enthalpy accurate to within 1 Btu/lb Relative humidity accurate to within 5% Sensor calibration data of sensors used for control of economizer are plotted on sensor performance curve. Sensors used for the high limit control are located to prevent false readings, e.g. properly shielded from direct sunlight. Relief air. System is designed to provide up to 100% outside air without over-pressurizing the building

12 Cost Effectiveness 12 LCCA for 45,000 Btu/h HVAC system Cost is much higher than expected for conservative estimate Cost includes 36 performance features from ARTU project Compared to this list of 10 features; Some are already common Incremental Installed Cost $ 3,202 Incremental Annual Maintenance $0 Total Incremental Cost $3,202 PV of Energy Savings $3,394 Lifecycle cost savings $192 Benefit/Cost Ratio 1.06

13 Code Change Proposal 4 13 SECTION 122 REQUIRED CONTROLS FOR SPACE- CONDITIONING SYSTEMS 122 (e) Shut-off and Reset Controls for Space-conditioning Systems. Each space-conditioning system shall be installed with controls that comply with Items 1, 2, and 3 below: 3. Multipurpose rooms of less than 1000 square feet, and classrooms and conference rooms of any size, shall be equipped with occupant sensor(s) to setup the operating cooling temperature set point to 75 F or higher and setback the operating heating temperature set point to 68 F or lower.

14 Code Change Proposal 4 14 SECTION 121 REQUIREMENTS FOR VENTILATION 121 (c) Operation and Control Requirements for Minimum Quantities of Outdoor Air 5. Occupant Sensor Ventilation Control Devices. Occupant sensors may be used to turn off ventilation dampers or fans when occupants are not present in accordance with the following: A. Occupant sensors shall meet requirements in Section 119 (d) and shall have suitable coverage and placement to detect occupants in the entire space ventilated. Occupant sensors controlling lighting may be used for ventilation as long as the ventilation signal is independent of daylighting or manual lighting overrides. Manual-on type lighting occupant sensors are not suitable for ventilation control. B. Where multiple rooms are served by a single zone box or ventilation fan, then each room shall have an occupant sensor and occupant detection in any room shall cause the fan and ventilation or zone box ventilation to operate and required ventilation shall continue for 15 minutes after all rooms served are vacant. C. Provisions shall be made for the daily building purge when required in Section 121(c)2 to override occupant sensor ventilation lockout. D. Occupant sensor ventilation control may be used in conjunction with a demand control ventilation device complying with Section 121(c)4 that operates when occupancy is detected.

15 Cost Effectiveness 15 Revised energy savings analysis in progress Expected completion mid-april Req'd control per T-24 DCV DCV DCV Occ sensors Occ sensors Occ sensors Applicable spaces (of those previously considered) Conference Rooms <=40 sf/person Conference Rooms <=40 sf/person Conference Rooms <=40 sf/person Multipurpose rooms < 1,000 sf, classrooms Multipurpose rooms < 1,000 sf, classrooms Multipurpose rooms < 1,000 sf, classrooms Occ. Density Baseline - Min. Ventilation System Type ECM - fan control when vacant 30 sf/person 0.15 cfm/sf CAV package unit CAV fan off 30 sf/person 0.15 cfm/sf VAV package unit damper closes when vacancy 30 sf/person 0.15 cfm/sf VAV built up damper closes when vacancy 20 sf/person 0.5 cfm/sf CAV package unit CAV fan off 20 sf/person 0.5 cfm/sf VAV package unit damper closes when vacancy 20 sf/person 0.5 cfm/sf VAV built up damper closes when vacancy Occ sensors conference rooms 30 sf/person 0.5 cfm/sf CAV package unit CAV fan off Occ sensors conference rooms 30 sf/person 0.5 cfm/sf VAV package unit damper closes when vacancy Occ sensors conference rooms 30 sf/person 0.5 cfm/sf VAV built up damper closes when vacancy

16 Code Change Proposal 5: FDD 16 Currently a compliance credit in the performance calculation method Not required by Title 24 Credit toward complying with energy budget Transition to a prescriptive requirement Not required by Title 24 Sets the basis of performance standard

17 Code Change Proposal 5 17 SECTION 144 PRESCRIPTIVE REQUIREMENTS FOR SPACE CONDITIONING SYSTEMS 144 (m) Fault Detection and Diagnostics (FDD) for Packaged Direct-Expansion Units. All packaged direct-expansion units with mechanical cooling capacity at ARI conditions greater than or equal to 72,000 Btu/hr shall include a Fault Detection and Diagnostics (FDD) system in accordance with NA9 Fault Detection and Diagnostics.

18 Code Change Proposal 5 18 Nonresidential Appendix NA Appendix NA9 Fault Detection and Diagnostics NA9.1 System Requirements The following sensors should be permanently installed to monitor system operation and the controller should have the capability of displaying the value of each parameter: Refrigerant Pressure: Suction Line, Liquid Line Refrigerant Temperature: Suction Line, Liquid Line Air Relative Humidity: Outside Air, Supply Air Air Temperature: Outside Air, Supply Air, Return Air

19 Code Change Proposal 5 19 NA9.1 System Requirements The controller shall provide system status by indicating the following conditions: Compressor Enabled Free Cooling Available Economizer Enabled Heating Enabled Mixed Air Low Limit Cycle Active The unit controller shall manually initiate each operating mode so that the operation of compressors, economizers, fans, and heating system can be independently tested and verified. Faults shall be reported to a fault management application accessible by day-today operating or service personnel, or annunciated locally on zone thermostats. A performance indicator shall be provided, which will allow tracking of efficiency. The FDD System used shall be certified by the CEC and verified to be installed correctly.

20 Code Change Proposal 5 20 NA9.2 Faults to be Detected The FDD system shall detect the following faults: 1. Air Temperature Sensor Failure/Fault 2. Low Refrigerant Charge 3. Not Economizing When it Should 4. Damper Not Modulating 5. Excess Outdoor Air

21 Summary of FDD Products 21 Currently available fault detection by OEMs (matches NA9.2 Faults to be Detected) Air temperature sensor failure/fault Low refrigerant charge Not economizing when it should Damper not modulating Excess outdoor air Currently available products by third parties ClimaCheck by ClimaCheck, Inc. FDSI Synergy by Field Diagnostics, Inc. Sensus MI, developed by Univ. Nebraska

22 Summary of FDD Products 22 Third party products currently in development SMDS by PNNL Low cost SMDS by PNNL Low cost NILM by MIT Virtjoule by Virtjoule, Inc.

23 Cost Effectiveness 23 LCCA for 6-ton RTU Installed cost for OEM solution is much less than $ this is cost of third party solution w/much longer fault list Maintenance $ at 50% of expected for conservative estimate 75% probability of detecting faults with FDD Incremental Installed Cost $1,600 Incremental Annual Maintenance, 6 tons ($98) PV of Annual Maintenance, 6 tons ($1,171) Total Incremental Cost, 6 tons $429 PV of Energy Savings, 6 tons $2,172 Lifecycle cost savings $1,743 Benefit/Cost Ratio 5.1

24 24 HVAC Controls & Economizing? QUESTIONS & COMMENTS

25 25 HVAC Controls & Economizing Additional slides

26 FDSI Insight V.1 Production Sensus MI ClimaCheck SMDS NILM Low Cost NILM Sentinel/Insight Beta Testing Virtjoule Low Cost SMDS HVAC Controls & Economizing Summary of FDD products 26 O X Basic FDD Extended FDD Low Airflow O O O O O O O Low/High Charge O O O O O O Sensor Malfunction O X O O O X Economizer not Functioning O X X O O O Compressor Short Cycling O X O O O O O O Excessive Operating Hours O X O O O O Performance Degradation O O O O O O O O Insufficient Capacity O X O O X O Incorrect Control Sequence O X O O O O O Lack of Ventilation O X O O X Unnecessary Outdoor Air O X X O O X Control Problems O X O O O O Failed Compressor O O O O O O O O Stuck Damper O O O O O X Slipping Belt O O O O O O Leaking Valves O O O X Unit Not Operational O X O O O O O O

27 Energy Simulation 27 Ran a series of EnergyPro simulations Occupancy Type Area (Square Feet) Number of Stories # HVAC Systems Total tons Avg sf/ton Occupancy Schedule Prototype 1 Fast Food 2, T-24 schedule Prototype 2 Grocery 81, T-24 schedule Prototype 3 Large Retail 137, T-24 schedule Prototype 4 School 44, T-24 schedule Prototype 5 Small Office 40, T-24 schedule Prototype 6 Small Retail 8, T-24 schedule Prototype 7 Large Office 112, T-24 schedule

28 Probability Analysis 28 Simulation assumes: 100% failure rate 100% chance FDD system detects fault 0% chance fault would be detected w/o FDD However, this is incorrect Probability analysis to avoid overestimating the energy savings

29 Probability Analysis 29 Failure Mode Fault incidence Prob. of detecting the fault w/fdd Prob. of detecting the fault w/o FDD Fault incidence x FDD benefit Air temperature sensor malfunction 2% 75% 25% 1% Refrigerant charge: 80% of nominal charge 85% 75% 50% 21% Not economizing when it should 30% 75% 75% 0% Damper not modulating 24% 75% 25% 12% Excess outdoor air 24% 75% 25% 12%

30 Maintenance Savings 30 FDD reduces service costs due to: reduced preventive maintenance inspections fault/failure prevention shifting service to low season better scheduling of multiple service activities reduced base visit fees shared tasks, e.g. recover refrigerant $1,171 PV savings over 15 yrs (6-ton RTU)

31 System Cost 31 FDSI and PNNL s tools $250 to $400 (OEM cost) or $1600 (building owner installed cost after factor of 4 mark-up). Sensus MI system $5,000 per building Best implemented at locations with many RTUs such as big box retail. Cost per RTU is less than FDSI Sentinel and SMDS Fault detection by OEMs: less faults, lower cost Highest cost of this suite of tools:$1600/rtu