Smart School Symposium Heating Ventilation and Air Conditioning Session HVAC Products. Richard Lord

Transcription

1 Smart School Symposium Heating Ventilation and Air Conditioning Session HVAC Products Richard Lord

2 Overview and Agenda My goal today is to give you quick an overview of the current status of HVAC products and near term improvements that should you can considered when evaluating School Upgrade programs The presentation will cover the following topic; Typical school Building Load Profiles Typically HVAC Equipment used in Schools Efficiency Metrics for HVAC Equipment Historical Perspective on Efficiency Requirements Recent and Future Efficiency Improvement Initiatives Future Industry Initiatives 2

3 School Building Load One of the key things we have learned in ASHRAE 90.1 is to model the typical buildings so that we can understand the load profiles as well as all the operating characteristics For this, ASHRAE 90.1, with support from PNNL, have developed 15 benchmark buildings of which two are schools (primary and secondary) Schools have a unique building load profile They are different than other buildings like office buildings; High internal people load with average 42.6 ft2/person vs. an office at 200 ft2/person (4.7 times higher occupancy density) Average plug load of 4.8 W/ft2 vs. offices at.45 W/ft2 (10.6 times higher) Weekday occupancy from 8:00 am to 8:00 pm, often with limited summer operation vs. offices with annual operation and similar operating hours High percentage of ventilation air with an average of 64% outside air during occupancy vs. offices at 27% (2.4 times higher) 3

4 Climate Zones Weather data is not the same, and has a big impact on building loads as well as the performance of HVAC equipment. ASHRAE 90.1 has divided the US and the World into 17 climate zones as shown in the following map. 4

5 California Climate Zones Title 24 does not use the ASHRAE climate zones and has further divided the California requirements into 16 California Specific climate zones as shown, but these can be mapped to ASHRAE zones so that we can look at building modeling work that ASHRAE 90.1 has done 5

6 School Load Data Metrics Using the ASHRAE 90.1 benchmark buildings models I have developed the following metrics for typical primary and secondary school. US Zone US City California Zone California City Summer Design Heating Design Drybulb Wetbulb Drybulb Wetbulb F F F RH Cooling Design Intensity Heating Intensity Heat/Coil Ratio ft/ton ft-hr/kbtu % Primary Secondary Primary Secondary Primary Secondary Primary Secondary 1A Miami % % 73% 1B Riyadh % % 64% 2A Houston % % 74% 2B Phoenix % % 65% 3A Memphis % % 74% 6 Los Angeles % 7 San Diego % 8 El Toro % 9 Burbank % 3B El Paso 10 Riverside % 11 Red Bulff % % 68% 12 Sacramento % 13 Fresno % 14 China Lake % 15 El Centro % 3C San Francisco 3 Oakland % % 76% 4A Baltimore % % 74% 4B Albuquerque % % 66% 4C Salem 4 Sunnyvale % % 77% 5A Chicago % % 76% 5B Boise % % 70% 5C Vancouver 5 Santa Maria % % 81% 6A Burlington % % 78% 6B Helena 2 Sata Rosa % % 72% 7 Duluth 1.0 Arcata % % 71% 8 Fairbanks % % 74% US Average % 73% California Avg % 74% Design % OA 6

7 School Load Profiles Over the years most design decisions and regulations have focused on the design conditions and full load operation. Full load and full ambient design conditions are only 0.4% of the operating hours and do not always represent the annualized energy It is also common for equipment to be oversized and in fact ASHRAE 90.1 Appendix G which defines requirements for building simulation, requires that cooling equipment be oversized by 15% and heating by 25% Building HVAC loads are typically calculated with maximum possible occupancy and worst case plugs loads Bottom line is equipment never runs at the design conditions and is always running at part load as well as reduced ambients This has resulted in new thinking about performance metrics as well as design features and options that I will talk more about 7

8 Climate Zone 3B Primary School Load Profile Equivalent to California climate zone 6-Los Angeles, 7-San Diego, 8-El Toro, 9-Burbank, 10- Riverside, 11-Red Bluff, 12, Sacramento, 13, Fresno, 14-China Lake, 15-El Centro 8

9 Climate Zone 3C Primary School Load Profile Equivalent to California climate zone 3-Oakland 9

10 Climate Zone 4C Primary School Load Profile Equivalent to California climate zone 4-Sunnyvale 10

11 Climate Zone 5C Primary School Load Profile Equivalent to California climate zone 5-Santa Maria 11

12 Climate Zone 6B Primary School Load Profile Equivalent to California climate zone 2-Santa Rosa 12

13 Climate Zone 7 Primary School Load Profile Equivalent to California climate zone 1-Arcata 13

14 Typical School HVAC Equipment The following are typical HVAC Systems that are used in schools Packaged Air cooled rooftops Air Cooled Central Chiller systems with fan coils or air handlers Water Cooled Central Chiller systems with fan coils or air handlers Geothermal Water Source Heat Pumps (WSHP) with DOAS for ventilation Single Packaged Vertical Air Conditioners (SPVAC) Packaged Air Cooled (Portable Class Rooms) Variable Refrigerant Systems with DOAS for ventilation 14

15 Typical Full Load Efficiency Metrics Minimum efficiency standards started back in the 1970 s Until recently the primary metrics used were full load efficiency metrics determined at defined common rating conditions EER Ratio of the Net Cooling Capacity in Btu/hr divided by the total unit power. This metric is typical used on most packed equipment, air cooled chillers, and VRF systems KW/ton Ratio of the total power input divided by the capacity in tons. This used for water cooled chillers COP Ratio of the output heating capacity in watts divided by the power input in watts. This is used for heat pump when operating in heating. E C, E T Combustion Efficiency. Used for gas and oil fired heating products 15

16 Typical Annualized Efficiency Metrics Recently the industry has started to used annualized metrics that also consider part load operation SEER Seasonal Energy Efficiency ratio which is the total cooling output of an air conditioner during its normal annual usage period for cooling (in Btu/h) divided by the total electric power input during the same period (in W). Used on residential and light commercial IPLV Integrated part load Value which is a weighted average of the EER, or kw/ton at 100%, 75%, 50% and 25% loads for a typical US commercial building and climate zone. Used for chillers. IEER Integrated energy efficiency ratio which is the weighted average of the EER, at 100%, 75%, 50% and 25% loads for a typical US commercial building and climate zone. HSPF - Heating seasonal performance factor which is the total heating output of a heat pump during its normal annual usage period for heating (in Btu/h) divided by the total electric energy input (in W) during the same period 16

17 Typical Efficiency Metrics Trends With the new annualized metrics the industry and efficiency standards are gradually switching from a focus on full load metrics to the annualized metrics These better represent the potential efficiency improvements that will be obtained when purchasing new more efficient equipment, but they do not represent the direct savings that will be obtained in a given building and climate zone They typically represent the performance of a HVAC units, but do not include all the power and efficiency impacts of the complete HVAC System. The current best approach to determine the energy savings in a specific building and climate zone is to run an energy model of a building using tools like EQuest, DOE2, EnergyPlus, HAP, Trace, etc But currently only about 20% of the buildings are being modeled as the modeling is expensive to run and time consuming 17

18 Current Industry Efficiency Standards The current approach to industry efficiency standards like ASHRAE 90.1, Title 24 and DOE federal requirements are to define prescriptive requirements for components like unit efficiencies They also then define prescriptive requirements for components like economizers, energy recovery, cooling towers, piping, controls, etc But not all the components are currently regulated This approach also does not factor in the system aspects of things like multiple chillers, ductwork pressure drop, pumping power, and more When looking at new systems or replacement systems you should consider the full system impact. We are working on new approaches for HVAC systems which I will talk more about. 18

19 Chiller Water System Efficiency Example ASHRAE 90.1 fan power requirement, no approach requirement and ignore water use Regulations Cooling Tower No regulations Do not address multiple chillers and towers although most are applied that way Condenser Water Pump Current 550/590 Chiller Standard and Certification focus ASHRAE 90.1 Full and part load efficiency Condenser Evaporator Compressor No focus on condenser water pumping power other than a pipe sizing requirement No focus on chilled water pumping power other than pipe sizing No integration of economizers, exhaust fans, ERV and IAQ Very little focus on the effective air distribution Chart prepared by Richard Lord Outside Air Air Handler Conditioned Space Chilled Water Pump No focus on duct pressure drop and very little on applied fan power 19

20 Packaged Ducted Rooftop System Example Economizer and outside air not reflected in ratings ERV/Rooftop CEF can be used for full load, but not part load and annualized Power Exhaust not included in ratings Demand ventilation not reflected in ratings Packaged Rooftop Rating of the rooftop EER and IEER with part of the fan power is covered by AHRI 340/360 but we do not certify the full operating map No annualized performance for heating Only part of the duct work pressure drop included in the ratings Very little focus on the effective air distribution Conditioned Space On VAV units reheat not reflected in ratings Chart prepared by Richard Lord 20

21 HVAC Efficiency Improvement Background Great progress has been made in building efficiency and HVAC unit efficiencies and this can be important when considering replacement units Chart based on ASHRAE 90.1 determination study conducted by PNNL 21

22 HVAC Efficiency Improvements As you can see considerable progress has been made in efficiency improvements with considerable progress made in 2010 with an overall improvement of 32% for regulated building loads More improvements also have been approved for the 2013 release of ASHRAE 90.1 standards which typically are aligned with the title 24 requirements In the following pages I will summarize some of the improvements that you should be aware of when consider school upgrades 22

23 Efficiency (Btu/hr) Rooftop Efficiency Improvements For packaged equipment including rooftops the IEER will increase by an average of 13% effective in 2016 Similar improvements also being made for heat pumps and split systems EER 2016 EER Series IEER 2016 IEER <65K 65K to 135K 135K to 240K 240K to 760K >760K Capacity Category (KBtu/hr) Chart based ASHRAE 90.1 Packaged Rooftop Efficiency Requirements 23

24 2015 Chiller Efficiency Change Details Chiller efficiencies are also being improved with increased full and part load requirements as well as expanded path B part load intensive requirements. Categories have also be revised and aligned ASHRAE ASHRAE Final Proposal Equipment Type Size Category Units Path A Path B ASHRAE Final Proposal Path A Path B Path A Path B Full IPLV Full IPLV Full IPLV Full IPLV Full IPLV Full IPLV Air Cooled Chiller < 150 Tons EER Tons EER < 75 Tons kw/ton Tons and <150 Tons kw/ton % 9.6% 1.5% 26.4% 5.6% 9.8% 1.5% 26.3% 3.8% 4.8% 2.5% 16.7% 7.1% 8.9% 5.1% 16.4% Water Cooled Positive Displacement Water Cooled Centrifugal 150 Tons and <300 Tons kw/ton Tons and <400 Tons kw/ton Tons and <500 Tons kw/ton Tons and <600 Tons kw/ton Tons kw/ton < 75 Tons kw/ton Tons and <150 Tons kw/ton Tons and <300 Tons kw/ton Tons and <400 Tons kw/ton Tons and <500 Tons kw/ton Tons and <600 Tons kw/ton Tons kw/ton % 6.9% 5.3% 18.5% 1.6% 3.7% 2.2% 16.3% 1.6% 3.7% 2.2% 16.3% 1.6% 3.7% 2.2% 16.3% 9.7% 7.4% 8.5% 22.4% 3.8% 7.7% -8.8% 2.2% 3.8% 7.7% -8.8% 2.2% 3.8% 7.7% 0.6% 11.1% 2.8% 5.3% 0.8% 2.5% 2.8% 8.9% 2.5% 5.0% 2.8% 8.9% 2.5% 5.0% 1.8% 7.2% 0.8% 5.0% 24

25 Other Prescriptive Requirements 25 In addition to the HVAC unit efficiency improvements there also have been changes made to other prescriptive requirements in 2010 and in the 2013 ASHRAE 90.1 standard and the new 2014 Title 24 requirements Addition of 2 speed indoor fan requirements New staging requirements for packaged units New economizer requirements including in Title 24 diagnostics and commissioning Economizer damper leakage requirements Lower threshold on demand ventilation Expanded requirements for energy recovery Controls requirements for VAV systems We do not have time to go through all of these, but I will cover some of the significant changes that will impact school energy efficiency

26 2 Speed Fan and Staging Indoor Fan Speed Control Because the power of the indoor fan decreases to the cube of the speed and the fan runs continuously during occupancy for ventilation, the savings are significant New requirements are being added to ASHRAE 90.1 and Title 24 for 2 speed fans on constant volume and inverters on VAV >110K Btu/hr effective 1/1/2010 >75K Btu/hr effective 1/1/2014 >65K Btu/hr effective 1/1/2016 Compressor Staging ASHRAE 90.1 and Title 24 are also adding requirements for compressor staging CV Units shall have a minimum of 2 stages >75K Btu/hr effective 1/1/2014 >65K Bu/hr effective 1/1/2016 VAV units shall have the following staging effective 1/1/ K to 240K minimum 3 stages >340K minimum 4 stages Additional staging and modulation 26

27 2 Speed Fan Savings When the speed of a fan decreases the airflow decreases directly with the speed, but the fan power decreases to the cube of the speed resulting in significant energy savings Compared to single speed indoor fan motor systems, Carrier s staged air volume (SAV) system utilizing variable frequency drive (VFD) and 2-speed indoor fan motor can save substantial energy. Up to 65%* Staged Air Volume % Energy Savings ($) * 60% 40% 20% 0% Miami Los Angeles Phoenix New York St. Louis Atlanta * Annual estimated electric energy savings utilizing Carrier s Hourly Analysis (HAP) Program v4.6. Based on cooling and ventilation fan runtime hours using ASHRAE 90.1 office application, default schedule, weather and building data. Carrier model 48/50TC 12 at.10 ($/kwh) energy rate. 27

28 Fan Energy Savings Additional energy savings are possible with further fan speed control and the new high efficiency Carrier 48/50LC is using a triple speed fan control The fan speed options also require multiple minimum position economizers to control minimum ventilation 28

29 Economizer Changes In addition to efficiency changes there also has been significant changes to the requirements for economizers Economizers are now required on all systems with a fan and a capacity greater than 54K all Title 24 zones and ASHRAE 90.1 zones 1a and 2a In addition new requirements have been defined for integrated economizers as to how they should operate during integration as a result of field problems. Testing on high limit sensors has also shown that there are issues with sensor accuracy and quality and new requirements have been added to Title 24 and the same are being added to ASHRAE 90.1 Tighter damper leakage requirements have been added for outside air as well as return air dampers There are also changes for the high limit set points as well as the high limit changeover methods. Due to problems with economizers, California as also expanded the requirements for economizer design and commissioning and this is also being considered by ASHRAE 90.1 and the IECC standard 29

30 Economizer Problems Several field studies have been conducted and the following problems have been found with economizers Damper Linkage Failure Economizer damper motor not functioning Economizer disconnected Minimum ventilation position not properly set Changeover sensor inaccuracy and failure Solar impact on changeover temperature sensor failure Supply temperature sensor failure and inaccuracy Integrated Economizer controls and operational issues Building pressurization (improper exhaust/relief) Exhaust air recirculation Damper blade leakage (outside and return) Lack of Maintenance Lack of and improper commissioning These are being addressed by the industry thru new economizer design, new economizer controllers, and new standards requirements like the Title diagnostics and commissioning requirements 30

31 Economizer Problems Damper Linkage Problems Damper Leakage Problems Economizer Hoods and Maintenance Problems Sensor and Actuator Problems High Limit Controls and Sensor Accuracy Integrated Economizer and Controls Problems 31

32 Airside Economizer Technology Shown is a typical packaged rooftop with an airside economizer 32

33 Typical Commercial Building Load Profile Economizer only Operation 1322 hrs Integrated Economizer Comp + Economizer 1316 hrs Mechanical Cooling No Economizer 73 hrs 33

34 Economizer Annual Energy Savings The following chart shows the energy savings for an integrated economizer vs. a small rooftop unit without an economizer for a small office building. Note that these savings are not factored into the IEER metric 8 - Fairbanks 7 - Duluth 41.97% 44.73% 6B - Helena 37.96% 6A - Burlington 31.99% 5C - Vancouver 41.05% 5B - Boise 37.13% 5A - Chicago 29.41% 4C - Salem 4B - Albuquerque 37.24% 35.69% 4A - Baltimore 30.70% 3C - San Francisco 39.71% 3B - El Paso 26.93% 3A - Memphis 13.28% 2B - Phoenix 2A - Houston 17.19% 15.77% 1B - Riyadh 11.37% 1A - Miami 4.95% California climate zones 0.00% 5.00% 10.00% 15.00% 20.00% 25.00% 30.00% 35.00% 40.00% 45.00% 50.00% 34

35 Economizer Integration Requirements Building standards require that economizers be integrated where the economizer can be used and supplemented by mechanical cooling Some controls today do not do this properly, especially for VAV and the economizer and compression fight each other due to poor control integration as shown in the following plot New requirements have been added to ASHRAE to address this 35

36 Economizer Operating Hrs The following chart shows the operating hr profiles for a small office building in each of the ASHRAE climate zones and benchmark cities and the benefits of integrated economizers Economizer Only Integrated Mechanial Only 8 - Fairbanks 7 - Duluth 6B - Helena 6A - Burlington 5C - Vancouver 5B - Boise 5A - Chicago 4C - Salem 4B - Albuquerque 4A - Baltimore 3C - San Francisco 3B - El Paso 3A - Memphis 2B - Phoenix 2A - Houston 1B - Riyadh 1A - Miami Annual hrs California climate zones 36

37 Economizer Improvements The benefits of the use of economizers are significant but prior studies have shown actual savings in the field were not being obtained due to problems previously mentioned. So the industry has been working to improve the economizers and their performance Some of the things the industry has implemented are; New drive configurations using gears New digital economizer with electronic feedback Low leak dampers on outdoor and return air New sensors with digital signals and error detection New control logic for integrated control Reliability Cycle Testing Factory run testing Outdoor cfm sensors New microprocessor based controllers Integrated displays and error detection 2 speed Economizers for reduced energy use Integration with energy recovery 37

38 Economizer Improvements New Configurations Blade Seals Leakage Testing Gear Drive Economizers Life Testing 38

39 19:27:32 19:28:50 19:30:08 19:31:26 19:32:45 19:34:03 19:35:21 19:36:39 19:37:56 19:39:13 19:40:30 19:41:48 19:43:05 19:44:23 19:45:40 19:46:57 19:48:15 19:49:32 19:50:50 19:52:06 19:53:24 19:54:41 19:55:59 19:57:17 19:58:35 19:59:53 20:01:11 20:02:28 20:03:46 20:05:04 20:06:22 20:07:40 20:08:57 20:10:15 20:11:33 20:12:50 20:14:07 20:15:25 20:16:42 20:17:59 20:19:17 20:20:34 20:21:51 20:23:08 Economizer Improvements Advanced controllers With integrated diagnostics New digital sensors Many new smart economizer controllers : 57 ambient, free cooling, Y1 then Y2, B stayed off due to SAT Low Cool SAT Setpoint = 60 High Cool SAT Setpoint = 50 SAT Min High = 55 SAT Min Low = ECONOCMD ECONOPOS OA_TEMP SAT_DISP COMP_A COMP_B Y1 Y New high limit control concepts New integrated control logic to eliminate damper cycling 39

40 Title 24 Economizer Commissioning California has also added new requirements for inspection and commissioning of economizers. There are two options; Field commissioning using a defined procedure Factory certification with some field setup commissioning 40

41 Title 24 Economizer Diagnostics In addition Title 24 has also added requirement for economizer diagnostics in 2014 Economizer Fault Detection and Diagnostics is a mandatory requirement for all newly installed air-cooled unitary direct-expansion units, with mechanical cooling capacity at AHRI conditions of greater than or equal to 54,000 Btu/hr, and equipped with an economizer. Where required, the Fault Detection and Diagnostics (FDD) system shall meet the requirements of 120.2(i)2 through 120.2(i)9, as described below. Air-cooled unitary direct expansion units include packaged, split-systems, heat pumps, and variable refrigerant flow (VRF), where the VRF capacity is defined by that of the condensing unit. The following temperature sensors shall be permanently installed to monitor system operation: outside air, supply air, and return air Temperature sensors shall have an accuracy of ±2 F over the range of 40 F to 80 F The controller shall have the capability of displaying the value of each sensor The controller shall provide system status by indicating the following conditions: Air temperature sensor failure/fault. Not economizing when it should. Economizing when it should not. Damper not modulating. Excess outdoor air. Controller shall have a manual operating mode. Fault detection reporting shall be available to service personnel 41

42 Industry Efficiency Options to Consider Over the past 10 years the industry has also adopted a tiered efficiency approach with ASHRAE 90.1 and Title 24 being the minimum, but then there are tier II and III option standards like EnergyStar, CEE, and FEMP which should be considered in school upgrades. The following is an example of the Carrier rooftop Tiered Product Line 42

43 Future Efficiency Improvement Options Historical Approach (Business as usual) - Full Load Improvements We are approaching Max-Tech on many products and significant improvements in base product full load efficiencies will be limited and often not cost effective We also face issues with the phase down of the HFC refrigerants that are used today, and will have to evolve to new lower GWP refrigerants that may not be as efficient, could be semi-flammable and could be more expensive to apply Alternate Approaches to Consider 1. Switch to new part load or annualized metrics like IPLV for chillers and IEER for rooftops, splits, and VRF 2. Hybrid system with rating approaches like AHRI guideline V 3. Subsystems approaches (focus of discussion today) 4. Whole Building System approaches (ASHRAE Building Energy Quotient) 5. Defined commissioning requirements to make sure equipment runs correctly 6. Integrated Fault Detection (FDD) 43

44 Hybrid Systems The concept for a hybrid system approach is to take two or more technologies and combine them together utilizing some type of combined rating. During the annual operation each hybrid technology is used where it delivers the most benefit Some examples are; Airside economizer Hydronic economizer Free Cooling refrigerant cycles Integrated Heat Recovery Integrated Exhaust Air Energy Recovery Dual fuel heat pumps Thermal Storage Energy storage Desiccant systems Evaporative pre-cooling condensers Evaporative outdoor air coolers, direct and indirect Desuperheaters and integrated hot water heaters Solar assisted units 44

45 AAHX Example Combined Efficiency Exhaust Blower Return Air Plenum Balance of Unitary Air Conditioner ERV Unitary Air Conditioner ERV Recovered Energy Efficiency Ratio RTU Energy Efficiency Ratio RER Net conditioningrecovered by ERV Total electricalpower consumedby ERV RER Net conditioningcapacity of RTU Office Code Document Code 0 EER Total electric power by RTU EER CEF = Combined Efficiency Factor Example: Rooftop + ERV = System CEF (30 ton system) EER & RER = CEF 12.0 & = System EER for a 30 ton total system 45

46 EER or CEF Efficiency Comparison (ERV Example) Example shows how over the operating range a hybrid unit like an ERV/Rooftop can have further improvements at non standard rating conditions. This is also true for hybrid options like evaporative cooling Base Rooftop Unit EnergyX Model: Rooftop ERV Location: Tampa, FL Tampa, FL Altitude (ft) 0.0 ft 0.0 ft CFM Ext static press: 0.75" 0.75" Ventilation Air: 50% or less (economizer) 50% OA (1750 cfm) CEF vs Application EER Combined Rating Improvement Base Unit Application EER EnergyX System CEF Full load Rating Point Outdoor Air Temp (deg F) 46

47 Regulated Buidling Energy Use vs ASHRAE Average ASHRAE Requirements Possible Future Roadmap - Systems Commercial HVAC Efficiency Requirements 110% 100% 90% ASHRAE 90.1 Building Target 80% 70% MaxTech Limit Full Load Efficiency 60% 50% 40% Equipment Level Limit 30% 20% 10% Possible Path to nearly Net Zero Buildings Systems Approach & Renewable Energy 0% Year Chart is an estimate of possible future regulations to achieve Near Net Zero by 2034 based on studies done by Carrier on technical limits of HVAC equipment 47

48 Chilled Water System Example (Current) Current ASHRAE 90.1 Regulations (Prescriptive Approach) HP/GPM Full Load & IPLV Component Efficiency Requirements No Requirements Prescriptive Requirements HP/GPM Full Load & IPLV Maximum Fan Power CO2 Chart prepared by Richard Lord 48

49 Chilled Water System Example (Proposed) Proposed Systems Approach System Level Climate Zone Efficiency Requirements Annualized HVAC System Efficiency (annualized) Overall Efficiency Minimum Set by climate zone and building type and then component efficiencies can be traded off to meet the overall targets Maximum Fan Power CO2 Chart prepared by Richard Lord 49

50 HVAC Systems Concept The HVAC systems concept would involve the following; User would select from one of the 15 ASHRAE 90.1 Benchmark buildings closest to the proposed building (may need more building types). ASHRAE 90.1 committee would define the baseline system using industry reasonable best practices and this then would be the baseline HVAC System efficiency. This would include HVAC efficiencies as well as all components in the system (i.e.. Cooling towers, pumps, economizer, etc.) User would then run proposed system using the system computer tool (hourly) using the selected benchmark building, and weather data from one of ASHRAE climate zones benchmark cities. If the proposed HVAC system uses less power then the benchmark system then the system could be used. Key to the approach is that all annualized power of the complete system is considered User would be allowed to trade off all aspects of the system as long as the annualized energy use was equal to or less. (i.e.. Chiller efficiency, cooling tower approach, pumping power, economizers, energy recovery, fan power, etc) Goal is to start off with equal performance to the prescriptive approach 50

51 Questions 51