1. The University of Texas at Austin Spring 2012 Course: Field Measurements: Building Energy and IEQ CE 397 Instructor: Dr. Novoselac, Atila ECJ 9.236 Office (512) 475-8175 e-mail: atila@mail.utexas.edu http://www.ce.utexas.edu/prof/Novoselac Office Hours: Tuesday and Thursday 11:00 – 12:00 p.m.

2. Objectives Introduce the course –Motivation –Schedule –Evaluation –Logistics Describe other syllabus content Address any of your concerns

3. Introduce yourself Name? Grad/undergrad? Department? Your professional interest?

4. Motivation for taking this course Experimental part of your MS/PhD work Building commissioning Forensic engineering studies

5. 1.Gain an appreciation for field and laboratory measurements relevant to: building energy performance and indoor environmental quality. 2.Learn about measurement techniques, instrumentation and complexities associated with their use (including accuracy and interference issues). 3.Obtain hands-on experience (in lab and field) with a number of basic instruments used in field investigations of buildings. 4.Analyze data from field and laboratory measurements and assess performance of buildings and their components. Course Objectives

6. 1. Course introduction and lab and field work safety1 wk 2. Specifics of field and laboratory measurements 1 wk 3. Experimental error & quality control2 wks 4. Velocity, flow, and pressure measurements2 wks 5. Temperature, humidity, and heat and moisture flows 2 wks 6. Measurement of particulate matter 1 wk 7. Measurement of gaseous contaminants1 wk 8. Electric power measurement 1 wk 9. Signal processing and data acquisition 1 wk 10. Sample collection and analysis 2 wks Total 14 wks 6 Course Topics

7. There is no required textbook Instead Course notes Handouts Hard or electronic copies of reading materials –Book sections –Journal papers –Instrument manuals Textbook

8. Grading Midterm Test 20% Classroom Participation10% Homework Assignments 40% Final Project & Presentation30% 100%

9. Test (20%) In-class exam Based on: readings lectures assignments lab and field measurements 9

10. Participation (10%) Come to class and participate in measurements Let me know about class(es) you will miss Read assigned articles and contribute to discussion Submit homework assignments in time Participate as a team member Handle equipment properly

11. Homework Assignments (40%) Calculation assignments Measurement result processing Correlation development ….. 11

12. Final project (30%) Independent study related to your research topic or a forensic engineering problem Will include lab and field measurement results processing and analysis report writing presentation in class 12

13. Logistics Course website Class location and times PRC facilities Field trips/measurements Laboratory demonstrations Equipment Data analysis/record keeping Safety

14. Website http://www.caee.utexas.edu/prof/Novoselac/classes/CE397/ Class notes Electronic handouts Assignments Grades 14

15. 15 Class Location This classroom 50% of class time Pickle Research Center labs and UTest house 30% of class time Field events 20% of class time 33

16. PRC fasciitis 5 Laboratories in building: PRC 133 UTest house 16 133

17. Field measurement In the second part of the course A campus building Facade thermal lab at UT School of Architecture City of Austin fire department facilities Pecan Street Project test house Other residential and commercial buildings You are welcome to suggest a location 17

18. 18 Schedule I need your availability for classes in PRC Filed trips will be scheduled in advance - 10 to 15 days in advance 34

19. Lab and UTest house demonstrations Primarily me Other faculty BEE graduate students 19

20. 20 Equipment Equipment for field assignments should be organized at least a day before the assignment All students are responsible for checking equipment in and out and returning it to lab All equipment should be treated gently and any issues brought to my attention 36

21. Data analysis/record keeping Students are responsible for handling all the lab and filed work data You will need: Lab/field note books Flash drives for electronic data transfer Installed some of the equipment software on your computer 21

22. Safety Clothing Clothes that you don’t care about Nothing flowing No exposed skin except haands Close-toed shoes UT EH&S (Laboratory) Safety Training (by the end of the next week) http://www.utexas.edu/safety/ehs/lab/ http://www.utexas.edu/safety/ehs/train/oh101.html http://www.utexas.edu/safety/ehs/train/oh201.html

23. Other issues Course history Course work load Visiting lecturer Your questions ? 23

24. Introduction to lab and field work, examples Terminology Class Topics for today

25. Lab Measurement Strictly design experiments Focus on maintaining one group of parameter in a controlled environment to measure other Motivation: Mimic real environment for measuring certain phenomena Testing of product or technology Model development Validation ….. 25

26. Field Measurements Often the only way to document the real world Often conducted in conjunction with laboratory measurements Many phenomena can not be meaningfully modeled or reproduced in the laboratory

27. 27 Example of Lab Work: Convection Correlation Development Heat transfer at floor in a room with displacement ventilation Q=A·h· ΔT h=f( air velocity, temperature difference, geometry ) V or ACH T surf -T air or Tsurf-Tsupply Room dimensions

28. 28 Convection Correlation Development Experimental Design q [W/m 2 ] T air Flow rate [ACH] Air velocity h=f(T surf -T air_local ) h=f(ACH) Measured permeates: - Heat flux - Surface temperature - Air temperature - Supply air temperature - Flow rate - Air velocity

29. 29 Test room: - Strict energy and mass balance - Steady state condition Instrumentation: Heat flux (power meter) Temperatures (thermistors) Flow (pressure based flow station) Velocity (hot wire) Data acquisition Convection Correlation Development Instrumentation: Velocity sensors Thermistors Floor Air

30. 30 Convection Correlation Development Sensitivity analysis results: Effect of temperature Effect of flow rate Q=A·h_ temp_based ·(T surf -T air_local ) Q=A·h_ flow_based ·(T surf -T supply_air ) Convection correlation expressed as a function of volume flow rate is stronger than correlation expressed as a function of temperature

31. 31 Convection Correlation Development Results In our cases we had turbulent flow h ~ velocity 0.8 ~ ACH 0.8 Function fitting: least square method

32. 32 Example of Field Work: Energy Implications of Filters Does using a better filter increase energy use? Conventional wisdom: Yes For smaller buildings: Maybe not Flow, fan energy, system energy, SHR, AC capacity All DECREASE 15

33. 33 Experimental Design Why can’t this study be done in a laboratory? Monthly measurements in 17 buildings over the course of a year with different filters installed Additional measurements in test house 16

34. 34 Instrumentation Power draw Fan and compressor Pressure drop Filter and coil Temp. and RH Capacity Fan flow Duct leakage Major issue?

37. 37 Summary Fieldwork is very messy Confounding variables and outliers Need large sample sizes Expensive and time consuming 20

38. Terminology What is the difference between accuracy and precision? Note that these terms are often confused and conflated with other terms Accuracy – “Capability of an instrument to indicate the true value of a measured quantity.” Precision – “Repeatability of measurements of the same quantity under the same conditions; not a measure of absolute accuracy” Precision not often reported Reference ASHRAE Guideline 2

39. Terminology Example of accuracy and precision: High accuracy, low precision Low accuracy, High precision Good measurement result is both: accurate and precise

40. Some Comments about Instrument Accuracy Manufacturers are almost always optimistic Make the difference between accuracy defined for full scale and reading Instrument 1: Accuracy: ±1.5% of full scale Repeatability: ±0.5% of full scale Instrument 2: Accuracy: ±1.5 % of reading (limited in certain range) Repeatability: ±0.5% What is Repeatability ?

41. Some Comments about Instrument Accuracy Accuracy is rarely constant over Range Assume frequent calibration Requires standard Calibrate over range of interest Don’t use complicated calibration curves Anything other than linear requires justification Consider arrangement with multiple sensors

42. 42 Other things that you should care about Sensitivity Sensitivity of the sensor is defined as the slope of the output characteristic curve Thermistors Resistor Temperature range Which one is more sensitive?

43. Other things that you should care about Response time Can be defined for other % values Standard definition

44. Other things that you should care about Response time Hobo U12 internal temperature sensor Response time in airflow of 1m/s (2.2mph) 6 minutes, typical to 90% Telaire 7001 CO 2 sensor <60 seconds to 90% of step change How do you use these values?

45. 45 Other things that you should care about Hysteresis Sensor should follow the changes of the mesured parameter regardless of which direction the change is made; hysteresis is the measure of this property How this affects the instrument accuracy?

46. Other things that you should care about Resolution the smallest detectable incremental change of input parameter that can be detected in the output signal Hobo U12 internal relative humidity sensor 0.03% RH Telaire 7001 CO 2 sensor ±1 ppm How do you use these values? Note that resolution can be limited by data logger

47. Other things that you should care about Range and detection limit How do you use these values? Note that you are often trading off range and resolution and/or accuracy Example: Measuring CO 2 with Telaire 7001 CO 2 sensor

48. 48 Other things that you should care about Example: In our test house we use CO 2 as tracer gas We use Telaire 7001 CO 2 sensor for concentration measurement What is the range accuracy and detection limit? http://www.microdaq.com/telaire/index.php

49. (Some) Real World Concerns First and operating cost Ease of use Safety Durability Flexibility Reliability Power requirements Environmental requirements/conditions