2 - DCV 12.12.13 - MAEEP - DCV 12.12.13_1.pdf · ASHRAE 62.1-2010 Written into the actual standard...
Transcript of 2 - DCV 12.12.13 - MAEEP - DCV 12.12.13_1.pdf · ASHRAE 62.1-2010 Written into the actual standard...
12/6/2013
1
Demand Controlled Ventilation (DCV)
Ryan R. Hoger, LEED [email protected]
Ryan R. Hoger, LEED [email protected]
Comfort Is More Than Just The Right Temperature…
Comfort = Temperature + Ventilation
Ventilation Control
12/6/2013
2
The same way it was in 1930.
With Fixed Ventilation!
How is ventilation provided in buildings today?
Ventilation Control
Minimum Ventilation Rates
12/6/2013
3
Inefficient!
Building codes require ventilation rates based on cfm/person: (typically 20 cfm/person)
Max Occupancy: 25 people = 500cfmActual Occupancy: 5 people = 500cfmActual Occupancy: 1 person = 500cfm
Fixed Ventilation
Fixed Ventilation In a Multi-Zone VAV BuildingTotal cfm = Max occupants X 20 cfm
There Is No Control!
Ventilation Control
12/6/2013
4
Temperature Control InA Multi-Zone VAV Building
• Measure In Each Zone• Control Based On Actual Load
What if we did the same thing with ventilation?
Temperature SensorTemperature + Ventilation Sensor
Delivers
The RIGHT Amount of Fresh Air,
To The RIGHT Place,
At The RIGHT Time…
Great Idea!
But How Does It Work?
12/6/2013
5
Indoor Air Quality
FIRST ALARM (TWA)
SECOND ALARM (STEL)
SENSOR LOCATION
RADIUS OF DETECTION
Temperature & Humidity N/A N/A N/A N/A
Carbon Dioxide (CO2) 800-1200 ppm 5000 ppm5 ft. above floor 20 ft.
Oxygen (O2)19.5%
(O2 depletion)22%
(O2 saturation)
CO2 Basics
• CO2 is NOT a contaminant, it is a colorless, odorless gas found naturally in the atmosphere– Outdoor levels are fairly constant at 400 +/- 25
ppm– Typical indoor levels 400 to 2,500 ppm– Not harmful unless concentrations reach 30,000
ppm • Carbon Monoxide (CO) and Carbon Dioxide are
NOT the Same
12/6/2013
6
People exhale CO2 at concentrations of 4% (40,000 ppm)
Normal room concentrations are in the range of 400 - 1200 ppm
As a gas, CO2 diffuses and equalizes rapidly throughout a room (like humidity)
CO2 Basics
• CO2 production by people is very predictable based on activity level
• Doubling the people in a room will double CO2production
CO2 and Ventilation Rates
12/6/2013
7
Actual Occupancy 25 people = 500cfmActual Occupancy 5 people = 100cfmActual Occupancy 1 person = 20cfm
Ventilation based on actual occupancy!
Ventilation Control
Zone Ventilation Control
12/6/2013
8
Research & Studies
• Numerous Studies Confirm that Correct Ventilation:• Increases Productivity• Improves Occupant/Customer Satisfaction • Helps Prevent Sick Building Syndrome Health
Affects
DOE/Lawrence Berkeley LabsIndoor Environment In Schools
Pupils’ Health & Performance In Regard To CO2 Concentrations
A significant correlation was found between decreased performance and high CO2 levels (lower ventilation rates).
Research & Studies
“Air Quality and Ventilation” ranked very high (#2 of 25) on the list
of tenant retention issues in a recent survey conducted by
Real Estate Information Systems.
• Numerous Studies Confirm that Correct Ventilation:• Increases Productivity• Improves Occupant/Customer Satisfaction • Helps Prevent Sick Building Syndrome Health
Affects
12/6/2013
9
Research & Studies
DOE/Lawrence Berkeley Labs Evaluation of
Sick Leave Statistics vs. Ventilation Rates
(3720 employees / 40 buildings):
Optimal ventilation reduces sick time costs. For every $1 spent on ventilation cost,
$2 are saved in sick time.
• Numerous Studies Confirm that Correct Ventilation:• Increases Productivity• Improves Occupant/Customer Satisfaction • Helps Prevent Sick Building Syndrome Health
Affects
nChart compares ventilation usage throughout typical day using purple to represent “demand controlled” and green to represent “constant”nDifference between equates to significant savings
DCV Savings
Federal Energy Management Program Study
12/6/2013
10
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Office Retail Restaurant School
Research FindingsDemand Control Ventilation
Energy required, DCV control applied
HUGE Savings
Energy wasted - no DCV
SCHOOL$6,910
Annual Savings15 mo. ROI
THEATRE$11,530
Annual Savings8 mo. ROI
SCHOOL$20,051
Annual Savings18 mo. ROI
THEATRE$17,603
Annual Savings7 mo. ROI
RETAIL$18,729
Annual Savings5 mo. ROI
OFFICES$7,112
Annual Savings12 mo. ROI
OFFICES$3,448
Annual Savings15 mo. ROI
Examples of Potential Energy Savings and ROI
12/6/2013
11
FEMP Study• 4 CO2 sensors per floor– Energy Model
$81,293 annually$3,000 per floor$0.22/ft2
– Actual saving for 6 months was $133,805
Application
Ratin
g
Application
Ratin
g
Application
Ratin
g
Correctional facilities Specialty shops Hospitals and medical Cells A Barber and beauty B Patient rooms BDining halls (Note 2) B Reducing salons B Medical procedure CGuard stations C Florists B Operating rooms C
Dry cleaners and laundries Clothiers B Recovery and ICU BCommercial laundry B Furniture B Autopsy rooms CCommercial dry-cleaner C Hardw are B Physical therapy AStorage and pickup B Supermarkets B Lobbies and w aiting areas ACoin-operated laundries A Pet shops C Hotels, resorts and Coin-operated dry C Sports and amusement Bedrooms B
Education and schools Spectator areas A Lobbies AClassrooms A Industrial facilities Conference rooms ALaboratories (Note 4) B Heavy manufacturing C Meeting rooms ATraining shops B Light manufacturing B Ballrooms and assembly AMusic rooms A Materials storage C Gambling casino BLibraries A Training facilities C Game rooms ALocker rooms C Painting and finishing C Ice arenas AAuditoriums A Food and meat processing C Sw imming pools CSmoking lounges (Note 3) B Office buildings A Gymnasiums A
Food and beverage service Retail stores Ballrooms and discos ADining rooms (Note 2) B Sales floors A Bow ling alleys ACafeterias (Note 2) B Dressing rooms A Theaters ABars, cocktail lounges B Malls and arcades A TransportationKitchens C Shipping and receiving C Waiting rooms A
Garages, repair and service C Warehouses C Platforms A
Rating Legend: A Recommended B Possible (Note 1) C Not Recommended
Determine if CO2 Control is Appropriate
12/6/2013
12
Control Setpoints
.
400
600
800
1,000
1,200
1,400
1,600
1,800
2,000
2,200
2,400
30 cfm/person25 cfm/person
20 cfm/person
15 cfm/person
10 cfm/person
8 cfm/person
6 cfm/person
5 cfm/personUnacceptable
Very Poor
Poor
Under Ventilated
Marginal
Ideal
Over Ventilated
Typical OutsideLevels
2,600
Vent
ilatio
n R
ate
Condition OfIndoor Air
Need ToIncrease
Outside AirVentilation
OpportunityTo Save Energy
By ReducingVentilation
Insi
de C
O2C
once
ntra
tion
(ppm
)
CO2 Control Point Depends on:• Outdoor CO2 Level (typically 450 ppm)• Required cfm/person ventilation rate
If OA CO2 is 400 ppm:20 cfm/person = 930 ppm CO215 cfm/person = 1,100 ppm CO210 cfm/person = 1,450 ppm CO2
• Proof of Compliance
Using CO2-based ventilation control ensures compliance to codes and standards
Benefits of Ventilation Control
Now Allowed by Most Mechanical Codes
International Mechanical Code (IMC)
Local Codes
ASHRAE Standard 62.1
12/6/2013
13
ASHRAE 62.1-2010
Written into the actual standard since ASHRAE
62-2004
Now Allowed by Most Codes
Commentary To The International Mechanical Code (IMC)Section 403.3.1
“The intent of this section is to allow the rate of ventilation tomodulate in proportion to the number of occupants. This canresult in significant energy savings. Current technology can permitthe design of ventilation systems that are capable of detecting theoccupant load of the space and automatically adjusting theventilation rate accordingly.
For example, carbon dioxide (CO2) detectors can be used to sensethe level of CO2 concentrations which are indicative of the numberof occupants. People emit predictable quantities of CO2 for anygiven activity, and this knowledge can be used to estimate theoccupant load in a space.”
Was written into the actual code for IMC 2006
Now Allowed by Most Mechanical Codes
12/6/2013
14
• Proof of Compliance
Also required in green codes such as ASHRAE 189.1, IgCC, and LEED
Benefits of Ventilation Control
Now Required by Most Energy Codes
International Energy Conservation Code (IECC)
Local Codes
ASHRAE Standard 90.1
ASHRAE 90.1-2007
This language is the same for IECC 2009
which is required by law in most states
IECC 2012 requires DCV at 25 people per
1000 ft2
DCV Now Required by Most Codes
12/6/2013
15
Why Now?
• Digital Control Systems– Integration of ventilation control
• Increased Ventilation Rates (ASHRAE/IMC)
• Increasing Energy Costs• Required by Energy Codes• Decreasing Sensor Costs (First & Life
Cycle) & Increased Sensor Reliability
Sensor Cost• Control system integration• Sensor technology and
integration (CO2 + Temp)• Volume increases
1992 1997 2003
$1500
$500 Installed CostPer Point
12/6/2013
16
Sensor Reliability• 15 Year design life• Non-interactive,
selective to CO2 only• Stable - lifetime
calibration
Self Calibration of a CO2 Detector
• Automatic Baseline Calibration (ABC Logic)
• Self calibrating algorithm
• Considers lowest CO2
level every 24 hrs
• Looks at long term changes in baseline
• Applies a correction factor for calibration
Slight Long Term Sensor Drift Calculated Over Number Of DaysTEMA Corrected Baseline
1000
900
800
700
600
500
400
300Days
Indo
or C
O2
Con
cent
ratio
n
12/6/2013
17
Self Calibration of a CO2Detector
0
100
200
300
400
500
600
700
800
2000/12/2914:58'08
2000/12/3007:38'08
2000/12/3100:18'08
2000/12/3116:58'08
2001/01/0109:38'08
2001/01/0202:18'08
2001/01/0218:58'08
2001/01/0311:38'08
2001/01/0404:18'08
PPM
Sensor 1Sensor 2Sensor 3
Sensor Reliability
200
300
400
500
600
700
800
900
1000
1100
1200
1300
1400
12/27 12/28 12/29 12/30 12/31 1/1 1/2 1/3 1/4 1/5 1/6 1/7 1/8 1/9 1/10 1/11
Day
CO
2 C
once
ntra
tion
(ppm
)
1 2 3 4 5 6 7 8 9 11 12 13 14 1510
Self Calibration Over 14 Days
12/6/2013
18
Long Term Sensor Stability
0250500750
10001250150017502000
1
365
729
1093
TIME (DAYS)
PPM
(CO
2)
Test Gas: 980 ppm CO2 in Nitrogen
Stat, Econ, and DCV Energy Savings
12/6/2013
19
Vehicle Demand Controlled Ventilation
Up to 80% fan energy reduction!!!Parking garagesLoading docksVehicle bays
– Fire stations– Car dealershipsBus terminals
Case Study – Parking Garage
Ventilation fans ran 24/7– 1.5M kWh annually– $242,000 annually
Installed– 41 CO sensors– 8 VFDs
$160,000 install cost90% reduction in fan energy
– Saved 1.35M kWh annually– Saved $217,800 annually– Simply payback of 9 months
12/6/2013
20
Alarm Setpoints
Time weighted average (TWA):Concentration levels that nearly all workers can be exposed to, during an 8 hour workday or 40 hour workweek, without suffering adverse affects
Short-term exposure limit (STEL):Maximum concentration to which workers can be exposed for a period of 15 continuous minutes
Ceiling concentration level (CCL):Exposure limit that should not be exceeded even momentarily
Toxic Gases
Standards
EXPOSURE LIMITS– OSHA PEL - Occupational Safety and Health
Administration (OSHA) permissible exposure limit (PEL) for CO is 50 PPM as an 8-hour time-weighted average (TWA) concentration [29 CFR Table Z-1]
– NIOSH REL - National Institute for Occupational Safety and Health (NIOSH) has established a recommended exposure limit (REL) for CO of 35 PPM as an 8-hour TWA and 200 PPM as a ceiling [NIOSH 1992]
– American Conference of Governmental Industrial Hygienists (ACGIH) has assigned CO a threshold limit value (TLV) of 25 PPM as a TWA for a normal 8-hour workday and a 40-hour workweek [ACGIH 1994, p. 15]
12/6/2013
21
CO – Carbon Monoxide GasA colorless, odorless, and tasteless gas. It is the product of the incomplete combustion of carbon compounds. Carbon monoxide is a major industrial gas with many applications in bulk chemical manufacturing.Carbon monoxide is a toxic gas
– TWA (8 hour): 25 ppm (2007 ACGIH)– Common type of poisoning– Attaches to hemoglobin more readily than
oxygen, impairing the ability to transport oxygenSymptoms of exposure include:
– Headaches– Flu-like effects– Toxicity of central nervous system and heart
(larger exposures)
NO2 – Nitrogen Dioxide
Reddish-brown gas (above 70°F) with a pungent, acrid odorResult of incomplete combustionReacts with water to form Nitric AcidExposure routes – inhalation, ingestion, skin and/or eye contact.Symptoms – irritation of the eyes, nose, & throat. Decreased pulmonary function, chronic bronchitis, breathing difficulty, & chest painTarget Organs – Eyes, respiratory system, cardiovascular system
12/6/2013
22
State of Gases in Ambient Air
The density of the gas determines where gas can be detected
At ceiling level:Lighter than air
At breathing level:Equivalent to air
At floor level:Heavier than air
Be Strategic About Locating Sensors
12/6/2013
23
Determining the Number of Sensors
The radius of operation of units defines the quantity of transmitters used within specific applications
*Sources of gas must be mobile
This determination is particular to each manufacturer.
Gas Radius of detection Area covered
CO*, NO2* 50 ft 10,000 ft2
Others 20 ft 1,600 ft2
Indoor Parking Garages
FIRST ALARM (TWA)
SECOND ALARM (STEL)
SENSOR LOCATION
RADIUS OF DETECTION
Carbon Monoxide (CO) 25 ppm 200 ppm 5 ft. above floor
50 ft.Nitrogen Dioxide
(NO2)0.72 ppm 2 ppm 1 ft. below ceiling
12/6/2013
24
Zoning
ZONE 1
ZONE 2
ZONE 3ZONE 1
ZONE 2
ZONE 3
Reduces energy costs• Average/compare gas levels• Control relay activation
Use energy only as needed, where needed!
Energy Savings Estimation Tools