1. Objectives Summarize Electric Power Measurement
Learn about CO and CO2 measurement and instrumentation
Discuss next week field measurements

2. Portable (Field) power meter and data logger

3. Single phase two wire

4. Single phase three wire

5. Three phase four wire

6. Electric power meters Large variety: + power meter with data logger
Inexpensive power meter
Power meter with power supply

7. Overview of CO2 and CO Why make these measurements in the field?
Some background information
Types of devices for each (overview)
Pros and cons of devices (including accuracy)

8. CO2 - Standards & Guidelines
OSHA: 5,000 ppm (8-hr average)
ASHRAE ( ): Cindoor – Coutdoor < 700 ppm
U.S. Navy (subs) 6,000 – 10,000 ppm
Observations in medical literature (Clark, 1996)
1, min (fatigue, lack of concentration, short. breath)
1,200 ppm long-term (calcium deposition in tissues)
> 2,500 ppm symptoms of oxygen deprivation in children
> 60,000 ppm (6%); possible narcosis / death (within minutes)

9. Carbon Dioxide (CO2) Metabolic generation rate
Ventilation requirements
ASHRAE Standard 62.1

10. Metabolic Generation Rate
ASTM D6245
Also ASHRAE Fundamentals Ch. 8 (2005)
AD = 1.8 for adult, for kids
RQ = 0.83 when M = 1 met
RQ = 1 when M = 5 met 10

11. ASHRAE Standard

12. CO2: Measurement Techniques
Non-dispersive infrared (NDIR) = most common
Electrochemical (reduce CO2 / generate current)
Photoacoustic (CO2 absorbs / T up to P pulse)
Potentiometric (CO2 to solution – changes pH)
Gas chromatography w/ MS or TCD
High sensitivity
High cost

13. Non-dispersive infrared (NDIR)
Measures the infrared light absorbed by carbon dioxide as it passes through a flow-through IR absorption cell
Possible interference from other ionic species
- Interferences from other IR-absorbing gases are minimized by use of a highly wavelength-specific detector
Issues:
…..

14. CO2: NDIR Detection See ASHRAE PDS IV
Absorption of IR light (CO2 peak 4.3 µm)
IR light source passed through narrow band filter
Higher CO2 = greater IR absorption
Interferences: H2O, CO, CH4 (absorp 4 – 7 µm)
Accuracy = 50 to 100 ppm up to 10,000 ppm
Hold calibration a long time ???
Cost: expensive for HVAC industry , affordable for Field work

15. Electrochemical
CO2 diffuses into the sensor through a porous membrane to the working electrode where it is case electrochemical reaction. This reaction results in an electric current that passes through the external circuit. the counter electrode is a reduction.
Advantages/disadvantages:
Can be very inexpensive
Drifting,….

16. Carbon Monoxide (CO) Major sources Standards Cigarette smoke
Incomplete bringing in HVAC and Cooking systems
Car exhaust ….
Standards
9 ppm (8-hour average) - NAAQS
35 ppm (1-hour average) – NAAQS
50 ppm – STEL/TWA – OSHA
400 ppm (15 minutes) - ACGIH
1,500 ppm (30 min) – IDLH (OSHA)

17. Example: Cooking – Natural Gas

18. Measurement of Carbon Monoxide
Electrochemical (common for hand held or home)
Two electrodes
Oxidize CO to CO2 – current generated
Biomimetic (gel cell)
Synthetic hemoglobin – darkens in presence of CO
Semiconductor (wires of tin dioxide / ceramic base)
CO reduces resistance
High CO
Non-Dispersive Infrared Detection (NDIR)
Used for emissions testing
Absorption band

19. Instruments for CO andCO2 that you will use
HOBO U12 (datalogger)
Telaire 7001 CO2 analyzer (NDIR)
HOBO CO Analyzer (electrochemical)
Specs:

20. Lab exercises - next week
PRC on Tuesday
preparation
Field
Wednesday or Thursday 20