CEE 243: Week 8 Benchmarking

Transcription

1 : Week 8 Benchmarking

2 Cross sectional benchmarking compares a building to other similar buildings / 2

3 Heating energy for an academic building is plotted on the y-axis in therms/sf-yr Each bar represents total heating energy for the prior 12-month period C: The horizontal line indicates the benchmark performance for similar buildings 3

4 Longitudinal benchmarking compares a building to itself. Is LEED Astray? 121 LEED buildings (Turner and Frankel 2008)

5 Malmo, Sweden: Actual energy much worse than Predicted Source: Sustainable City of Tomorrow CEE 243 5

6 Malmo, Sweden: Actual energy much worse than Predicted Source: Sustainable City of Tomorrow CEE 243 6

7 Building in Ireland: simulated and measured performance 7

8 Y2E2 energy cost comparison (designer) Scott Gould, Stanford Facilities 8

9 Y2E2 Assessment of performance given Functional intent and processes to do so: Q5 Week 8 - Tuesday

10 Focus of attention 10

11 Diagram to focus attention? 11

12 Clear focus of attention 12

13 Clear focus of attention 13

14 Sequence of Operations rule "(Use when daytime outside air temperature exceeded 75ºF) Daily, during unoccupied hours, the windows shall be opened to pre-cool the space in preparation for the next day. This will allow cool thermal mass storage in the space to offset some of the heat load developed during the day. The night purge space temperature setpoint shall be 65ºF (adj). After hours, if the outdoor air temperature drops below 65ºF (adj) and the space temperature is above 65ºF (adj), the windows shall be opened. The windows shall remain open until the space temperature reaches 63ºF (adj). At this point the windows shall close. If the space temperature rises above 65ºF (adj), the windows shall be opened again. When the space temperature reaches 63ºF (adj) the windows shall be closed. This sequence is to be repeated until the space no longer climbs above 65ºF (adj) or until the building is occupied" 14

15 Operationalized rules "(Use when daytime outside air temperature exceeded 75ºF) Daily, during unoccupied hours, the windows shall be opened to pre-cool the space in preparation for the next day. This will allow cool thermal mass storage in the space to offset some of the heat load developed during the day. The night purge space temperature setpoint shall be 65ºF (adj). After hours, if the outdoor air temperature drops below 65ºF (adj) and the space temperature is above 65ºF (adj), the windows shall be opened. 15

16 2:SEQUENCE OF OPERATIONS AND IF THEN RULES TCWS-SystemSupply Temperature Reset If the dewpoint of the outside air rises above 58 F (adj.) for a period of 5 minutes (adj.) the tempered chilled water supply set point shall be reset to stay 2 F above the dew point. If the outside air dew point drops below 58 F (adj.) for a period of 5 minutes (adj.) the tempered chilled water supply setpoint shall revert back to normal control. Rule 1: === Clause 1:If outside air dew point temp (1095) > 53 degrees for 5 minutes, Clause 2: Then the tempered chilled water set point (1195) shall reset to Dew Point temperature (1095) degrees Rule 2: Clause 1: If outside air dew point (1095) < 53 degrees for 5 minutes, Clause 2: Then the tempered chilled water set point (1195) shall reset to 55 degree setpoint Reference: to see if it is having an effect: tempered chilled water supply temp

17 Data associated with operationalized rule 17

18 (more detailed) data associated with operationalized rule 18

19 Data associated with operationalized rule 19

20 Data associated with operationalized rule Ways to highlight Features Implications? 20

21 Data associated with operationalized rule Ways to highlight features, implications? 21

22 Example of Irregular Missing Data - Lost Packets Tim Troxell explained that the occasional missing values I observed are related to the protocols for sending data through the system easily visible in a carpet plot pivot table to align the time stamps; rules that flagged the missing data and kept them from distorting results. 22

23 Point rule and conformance 23

24 Point rule and conformance 1. Parameter normal operating condition Is the supply temp reported in the operating range? 60 and above = green arrow, rising = yellow arrow normal Below =55 red arrow possible issue 24

25 Point rule and conformance 25

26 Simple conditional clause and conformance 26

27 Simple conditional clause and conformance 27

28 More complex conditional clause and conformance 28

29 More complex conditional clause and conformance 29

30 More complex conditional clause and conformance 30

31 More complex conditional clause and conformance 31

32 More complex conditional clause and conformance 32

33 OBVIOUS POTENTIAL CAUSES OF ABNORMALITIES One abnormality is that the supply temp for the tempered chilled water system occasionally drops to 32 degrees appears to be a sensor error mode data does not show any system anomalies, in spite of widely fluctuating values. 33

34 POTENTIAL CAUSES OF ABNORMALITIES rules I selected are very simple-- but there is actually a big leap between a conceptually basic rule and verifying that rule with detailed data. lack of specifics in the Sequence of Operations about how long the system takes to react, by how much and for how long the supply temp might need to exceed the set point, etc., makes it difficult to see whether the system performs as intended. 34