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Energy  Engineering

BTU  Conversion  Factors
 Electricity
 Natural Gas*
 Fuel Oil
 Propane
 Purchased Steam
  3,412  BTU   / KWH
92,000  BTU   / CCF
138,700 BTU  / GAL
91,600  BTU   / GAL
     933  BTU    / LB

  *   Heat value of natural gas varies so there is a conversion
       factor applied the the LDC. The BTU per CCF varies from
      85,000 to 105,000 BTU / CCF      ( 10X for MCF )

  * Therm       =    100,000    BTUs 
  *  Dth           =   1,000,000  BTUs    (MMBTU)

EnergyStar THERMAL CONVERSION CHARTS

Note: EnergyStar Portfolio Managers use Energy Intensity Index (EUI) or kBTUs//SF

Energy conversion charts

This page offers a quick reference for energy conversion measures. 

1 cubic foot of natural gas         =     1,000 BTU
1 pound of coal                         =   12,000 BTU
1 gallon of propane                   =    91,600 BTU
1 gallon of gasoline                   =   125,000 BTU
1 gallon of fuel oil #2                 =  139,000 BTU
1 gallon of fuel oil #6                 =  150,000 BTU
1 kilowatt hour of electricity     =      3,412 BTU

 

 

1 Million
BTU

24 Million
BTU

91,600
BTU

125,000
BTU

139,000
BTU

150,000
BTU

3,412
BTU

Natural Gas
cu. ft.

1,000
cu. ft.

24,000
cu. ft.

91.6
cu. ft.

125
cu. ft.

139
cu. ft.

150
cu. ft.

3.412
cu. ft.

Coal
lb.

83.33
lb.

2,000
lb.

7.633
lb.

10.417
lb.

11.583
lb.

12.5
lb.

0.2843
lb.

Propane
gal.

10.917
gal.

262
gal.

1
gal.

1.365
gal.

1.517
gal.

1.638
gal.

0.0372
gal.

Gasoline
gal.

8
gal.

192
gal.

0.733
gal.

1
gal.

1.112
gal.

1.2
gal.

0.0273
gal.

Fuel Oil #2
gal.

7.194
gal.

172.662
gal.

0.659
gal.

0.899
gal.

1
gal.

1.079
gal.

0.0245
gal.

Fuel Oil #6
gal.

6.667
gal.

160
gal.

0.611
gal.

0.833
gal.

0.927
gal.

1
gal.

0.0227
gal.

Electricity
kWh

293.083
kWh

7,034
kWh

26.846
kWh

36.635
kWh

40.739
kWh

43.962
kWh

1
kWh

  .................................

STEAM BOILERS

Boiler loads, or the capacity of steam boilers, are often rated in boiler horsepowers, lbs of steam delivered per hour, or BTU.  Lbs Steam delivered per HourLarge boiler capacities are often given in lbs of steam evaporated per hour under specified steam conditions. 

BTU - British Thermal Units: Since the amount of steam delivered varies with temperature and pressure, a common expression of the boiler capacity is the heat transferred over time expressed as British Thermal Units per hour. A boilers capacity is usually expressed as kBtu/hour (1000 Btu/hour) and can be calculated as

 W = (hg - hf) m

  where
   W = boiler capacity (Btu/h)
   hg = enthalpy steam (Btu/lb)
   hf = enthalpy condensate (Btu/lb)
   m = steam evaporated (lb/h)

Boiler Horsepower - BHP.   The Boiler Horsepower (BHP) is the amount of energy required to produce 34.5 pounds of steam per hour at a pressure and temperature of 0 Psig and 212 ?F, with feedwater at 0 Psig and 212 F.  An BHP is equivalent to 33,475 BTU/Hr . It should be noted that a boiler horsepower is 13.1547 times a normal horsepower.

     Example 1  
    
Horsepower (hp) can be converted into lbs of steam by multiplying hp with 34.5.
    200 hp x 34.5 = 6,900 lbs of steam per hour

 

     Example 2 :
    
Lbs of steam can be converted to HP by dividing lbs steam per hour by 34.5
     5000 lbs of steam / 34.5 = 145 hp boiler
   


............................................................................

Energy Cost Per BTU - Calculations

..................................................................

Benchmarking:

BTUs Per Square Foot for various classes of buildings


TEM presentation on Energy Benchmarking at NFMT 2016

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LIGHTING  GLOSSARY

.............................................................................

HVAC  GLOSSARY

..............................................................................

Electrical Engineering - Introduction

..............................................................................

LIGHTING

What is white lighting?   July 2015

 

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INSULATION

Wall Assembly R-Value

Component R-value
Wall - Outside Air Film

0.17

Siding - Wood Bevel 0.80
Plywood Sheathing - 1/2" 0.63
3 1/2" Fiberglass Batt 11.00
1/2" Drywall 0.45
Inside Air Film 0.68
Total Wall Assembly R-Value 13.73

R-Value Table

Material R/
Inch
R/
Thickness
Insulation Materials
Fiberglass Batt 3.14  
Fiberglass Blown (attic) 2.20  
Fiberglass Blown (wall) 3.20  
Rock Wool Batt 3.14  
Rock Wool Blown (attic) 3.10  
Rock Wool Blown (wall) 3.03  
Cellulose Blown (attic) 3.13  
Cellulose Blown (wall) 3.70  
Vermiculite 2.13  
Autoclaved Aerated Concrete 3.90  
Urea Terpolymer Foam 4.48  
Rigid Fiberglass (> 4lb/ft3) 4.00  
Expanded Polystyrene (beadboard) 4.00  
Extruded Polystyrene 5.00  
Polyurethane (foamed-in-place) 6.25  
Polyisocyanurate (foil-faced) 7.20  
Construction Materials
Concrete Block 4"   0.80
Concrete Block 8"   1.11
Concrete Block 12"   1.28
Brick 4" common   0.80
Brick 4" face   0.44
Poured Concrete 0.08  
Soft Wood Lumber 1.25  
   2" nominal (1 1/2")   1.88
   2x4 (3 1/2")   4.38
   2x6 (5 1/2")   6.88
Cedar Logs and Lumber 1.33  
Sheathing Materials
Plywood 1.25  
   1/4"   0.31
   3/8"   0.47
   1/2"   0.63
   5/8"   0.77
   3/4"   0.94
Fiberboard 2.64  
   1/2"   1.32
   25/32"   2.06
Fiberglass (3/4")   3.00
   (1")   4.00
   (1 1/2")   6.00
Extruded Polystyrene (3/4")   3.75
   (1")   5.00
   (1 1/2")   7.50
Foil-faced Polyisocyanurate
   (3/4")
  5.40
   (1")   7.20
   (1 1/2")   10.80
Siding Materials
Hardboard (1/2")   0.34
Plywood (5/8")   0.77
   (3/4")   0.93
Wood Bevel Lapped   0.80
Aluminum, Steel, Vinyl
   (hollow backed)
  0.61
   (w/ 1/2" Insulating board)   1.80
Brick 4"   0.44
Interior Finish Materials
Gypsum Board (drywall 1/2")   0.45
   (5/8")   0.56
Paneling (3/8")   0.47
Flooring Materials
Plywood 1.25  
   (3/4")   0.93
Particle Board (underlayment) 1.31  
   (5/8")   0.82
Hardwood Flooring 0.91  
   (3/4")   0.68
Tile, Linoleum   0.05
Carpet (fibrous pad)   2.08
   (rubber pad)   1.23
Roofing Materials
Asphalt Shingles   0.44
Wood Shingles   0.97
Windows
Single Glass   0.91
   w/storm   2.00
Double insulating glass
   (3/16") air space
  1.61
   (1/4" air space)   1.69
   (1/2" air space)   2.04
   (3/4" air space)   2.38
   (1/2" w/ Low-E 0.20)   3.13
   (w/ suspended film)   2.77
   (w/ 2 suspended films)   3.85
   (w/ suspended film and low-E)   4.05
Triple insulating glass
   (1/4" air spaces)
  2.56
   (1/2" air spaces)   3.23
Addition for tight fitting drapes or shades, or closed blinds   0.29
Doors
Wood Hollow Core Flush 
   (1 3/4")
  2.17
   Solid Core Flush (1 3/4")   3.03
   Solid Core Flush (2 1/4")   3.70
   Panel Door w/ 7/16" Panels 
   (1 3/4")
  1.85
Storm Door (wood 50% glass)   1.25
   (metal)   1.00
Metal Insulating 
   (2" w/ urethane)
  15.00
Air Films
Interior Ceiling   0.61
Interior Wall   0.68
Exterior   0.17
Air Spaces
1/2" to 4" approximately   1.00

Air Infiltration  Estimation Table

Home Condition ACPH*
Existing Home
Old very leaky home 1.00
Old moderately leaky home .75
Average home .50
Fairly tight home .45
Tightened Home
Average Tightening to Old Very Leaky Home .75
Average Tightening of Old Moderately Leaky Home .60
Average Tightening to Average Home .45
Blower Door Assisted Professional Sealing Job
(This is what E-Star certified energy raters do.)
.35
Blower Door Assisted Professional Extreme Tightening
 (E-Star certified energy raters can do this.)
.25 **
* Air Changes Per Hour is the amount of air inside your home that is replaced by outside air every hour.
** You probably don't want to lower your ACPH below .35 ACPH without adding a mechanical ventilation system to your home to bring in enough fresh air to maintain a healthy living environment. It is difficult to get your house to this level without professional help.

 

Heating System Efficiency Table

The following table will give you a rough idea of your current heating system efficiency. The better the condition and the more preventive maintenance it has had, the higher the efficiency:

Heating System Type Efficiency
Natural Gas, Propane and Oil Furnaces & Boilers
  30 years + .50-.60
  15-30 years .60-.65
  10-15 years .65-.70
  Newer Boiler .75-.80
  Newer Induced Draft Furnace
   (has fan to blow exhaust up the chimney)
.78-82
  Newer Sealed Combustion
   (usually has a PVC air intake and exhaust)
  High Efficiency Boiler
.85-.92
  Newer Sealed Combustion (usually has a PVC air intake and exhaust)
  High Efficiency Furnace
.90-.97
Electric Resistance
  Baseboard, Electric Furnace, Ceiling Radiant 1.0
Heat Pumps
  Older Air-to-Air 1.5-1.8
  Newer Air-to-Air 2.0-2.2
  Water (Ground) Source 2.8-3.2

Air Conditioner

SEER Value Table

The following table will give you a rough idea of your current air conditioner SEER value:

Age and Condition SEER
20 years old - Not well maintained 6.0
20 years old - Well maintained 6.5
10-20 years old - Not well maintained 7.0
10-20 years old - Well maintained 8.0
5-10 years old - Not well maintained 7.5
5-10 years old - Well maintained 8.5
Less than 5 years old 9.0
Base AC units put in today 10.0
High Efficiency Unit * 14.0

 * New standard is SEER 13. Some mini split A/C claim SEER of 22


Window/Door  Air Leakage Table

The following table will give you a rough idea of your window/door leakage rate

Window Quality

cfm/ft

Loose Fit - No Weatherstripping

1.01

Average Fit - No Weatherstripping

0.35

Average Fit - With Weatherstripping

0.18

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