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

Portable (Field) power meter and data logger

Single phase two wire

Single phase three wire

Three phase four wire

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

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)

CO2 - Standards & Guidelines OSHA: 5,000 ppm (8-hr average) ASHRAE (62-1999): Cindoor – Coutdoor < 700 ppm U.S. Navy (subs) 6,000 – 10,000 ppm Observations in medical literature (Clark, 1996) 1,200 ppm @ 15 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)

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

Metabolic Generation Rate ASTM D6245 Also ASHRAE Fundamentals Ch. 8 (2005) AD = 1.8 for adult, 0.8 - 1.4 for kids RQ = 0.83 when M = 1 met RQ = 1 when M = 5 met 10

ASHRAE Standard 62.1-2007

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

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: …..

CO2: NDIR Detection See ASHRAE PDS IV Absorption of IR light (CO2 peak absorb @ 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

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,….

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)

Example: Cooking – Natural Gas

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

Instruments for CO andCO2 that you will use HOBO U12 (datalogger) Telaire 7001 CO2 analyzer (NDIR) HOBO CO Analyzer (electrochemical) Specs: http://onsetcomp.com/products/sensors/tel-7001 http://onsetcomp.com/products/data-loggers/h11-001

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