Viridis Australasia?? 1

Transcription

1 Viridis Australasia?? 1

2 CBD Green Lease Green Star Operational Efficiency Regulatory BCA NABERS Driving transparency Fault Detection Maximise Building Value Success Voluntary Sub metering drivers 2

3 A NABERS rating of ZERO will not maximise the Building Value what went wrong? Current project cautionary tale New build, Finished PC Every Tenant DB has separate metering for light and power Sub meters are NABERS compliant and validated Commercial tower on track for NABERS rating of ZERO Green Star certification Most mechanical items are separately sub metered Mechanical system is efficient; building fabric is good; onsite PV Everything appears to be in place to achieve a NABERS rating of 5 Stars or better, but 3

4 Sub meter drivers and coverage Energy usage calculations electrical & thermal Meter validation Energy coverage Energy separation & metering Examples Summary 4

5 Meter Coverage CBD NABERS Base Bldg NABERS Whole Bldg NABERS Tenancy Green Lease Green Star BB Fault Detection BB Operating Efficiency Maximise Building Value Whole Bldg Base Building All Tenancies BB Large End Use BB End Uses BB Energy Exclusions Individual Tenancy Individual Tenancy Light & Power 5

6 Calculate energy usage from Single Utility Meter for Base Building (UMBB) Single meter for all BB energy use separate utility meter for tenant energy Simple calculation ( cost effective rating) Requires BB energy end uses to be hardwired and metered correctly according to NABERS rules BB energy use = UMBB Calculate energy usage from Utility Meter for Whole Building (UMWB) and tenant non utility meters Single meter for whole building energy use Non utility meters for tenancy energy Large BB energy uses are submetered, however not all BB energy uses sub metered cannot calculate BB energy use by summing submeters No meter for total tenancy usage Calculation involves subtracting tenant energy (exclusion) from whole building energy 1 data point Energy use = UMWB L1T1P L1T1L L1T2P L1T2L L2T1P L2T1L L2T2P L2T2L etc 41 data points for 10 storey building 6

7 Small End User Method Base Building For imports: less than 15% of building chilled water is imported Exclusions: Building exported to is less than 15% of rated building area; Design exported flow is less than 15% of max flow, or; Measured exported flow is less than 15% measured max flow For addition of chilled water into a rated space: For exclusion of chilled water from a rated space: Use flow meters or design parameters or another approved method to calculate percentage of chilled water, actual flow and maximum flows. Exclusions can be a maximum of 5% (calculation result when flow is 15% max) 7

8 Large End User Method Base Building Determine production method: Primary Production direct production of chilled water using elec or gas E.g. Use of a standard electric chiller to produce chilled water Secondary Production Use of by product of primary process to produce chilled water E.g. absorption chiller produces chilled water using waste heat from gasfired electricity generator 8

9 Calculation Details for primary production and energy transfer For an addition of energy (at any point in time) Transfer energy to be treated separately and 100% allocated to importer Determine % imported thermal energy vs total (true thermal energy) Apply this % total to raw energy inputs of entire production system as measured by sub meters this is the instantaneous energy demand to be allocated to the rated space. For an exclusion of energy (at any point in time): Transfer energy to be treated separately and 100% excluded from exporters energy Determine % exported thermal energy vs total (true thermal energy) Apply this % total to raw energy inputs of entire production system as measured by sub meters this is the instantaneous energy demand to be excluded from the rated space. 9

10 Final Calculation Step All calculations completed measure instantaneous demand (kw) and must be integrated over time to calculate energy consumption; 15 minutes is considered the maximum interval for recording instantaneous demand, except for very stable industrial systems where 30 minutes may be acceptable; 35,040 data records to be used for integration (4 x 24 x 365) (to calculate annual energy exclusion or apportionment) 10

11 Energy Balance Energy Inputs Electricity and gas Chillers Primary chilled water pumps Heat exchangers Cooling towers Condenser water pumps Energy Balance Energy Outputs Thermal energy from chillers (T, F, SH) Thermal energy for additions or exclusions (T, F, SH) Minimum approx 10 data points to determine instantaneous energy balance Approx minimum 350,000 data points (energy balance for 1 year) 11

12 Meters involved require validation Thermal Metering Measurement Standards Measurement system end to end accuracy incl. sensor, transmitter, cable losses, A/D conversion and cover expected reading range: Temperature: better than 3% Flow: better than 3% Integrated thermal meter: better than 5% Validation required if Non utility meter system includes: Electricity meter using current transformer (CT) A gas meter, or A Remote Meter Reading System 12

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14 BB energy if: it is required to ensure the office is safe, lit and comfortable to work in and it is not to service a special tenant need. Base Building Tenancy, Other External lighting Fire pumps Lifts AHUs Chillers Cooling Towers Tenant condenser water Amenities exhaust Tenant lighting Tenant controlled Supplementary AC for special tenant needs External signage Carpark ventilation & lighting Generator fuel gas, diesel Pumps chilled water, cold water, condenser water Tenant server room Tenant general power Amenities lighting and power Common area lighting & power lift lobby, foyer, plant room Fire stair pressurisation General exhaust Tenant generator fuel 14

15 Golden Rule for achieving an accurate rating that reflects the building performance: Understand the required Base Building energy coverage and design the energy architecture so that Base Building energy can be easily measured and all other energy can be easily excluded. Sounds simple, difficult to achieve in practice 15

16 Single tenant DB per level DB submetered DB also powering amenities M Tenant DB Amenities lighting and power Amenities lighting & power is BB energy end use All metered energy from DB must be included in BB rating Building may achieve worse rating Riser Tenant lighting and power 16

17 CHW Plant TM Commercial Tower Single chilled water system shared between commercial tower and non rateable space No thermal metering Shared chilled water system All chilled water system energy must be allocated to the commercial tower Since non rateable portion is relatively large, rating achieved may be zero TM Non rateable portion gaming, retail, public, 17

18 Good Practice: Understand required BB energy coverage Design energy system to separate BB energy from other energy Understand drivers for metering for your building design metering to achieve objectives Install sufficient sub meters to measure BB energy and exclude other energy (electrical and thermal) Give due consideration to sub metering requirements for shared systems Minimise number of meters required for accurate rating Validate meters prior to rating period Prove energy calculations for NABERS rating Consequence of Poor Practice: If energy separation is poor, Assessor may be required to allocate more energy to BB than it uses worse rating If metering is insufficient, energy that is not part of BB energy coverage may not be able to be excluded worse rating If large numbers of meters are required to calculate energy usage for the rating, rating cost will be high If meters are validated late in the rating period, some meters may turn out to be not operating correctly and the rating period must start again once the issues are corrected 18

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