house sunnyhotwater.com
 
Solar Hot Water Math, Formulas and Conversions
graph button
LIVE System Performance Graphs
See our real-time data updated once a minute
120 - 50 = DELTA T 70F
Click HERE
for Solar Hot Water Math Calculations
worldvoyagers
Iwalani's Voyage Around the World
Weekly logs of Iwalani's three year circumnavigation written by Philip Shelton, Amy P. Wood and Stewart the Cat.

small wv book

The "World Voyagers" Book
A true story of the three year circumnavigation by Philip Shelton, Amy Wood and Stewart the cat. From designing and building a 42 foot wooden cutter "Iwalani" to sailing around the world— this is not a watered down, sugar coated tale, but a "no holds barred" account of just what it's like to live a "dream."

BTU (British Thermal Unit) Calculations

1 BTU=1 DEGREE FARENHEIT INCREASE IN ONE POUND OF WATER.

8.34 POUNDS IN ONE GALLON

BTU EXAMPLE:
Incoming water 50F outgoing water 120F 120 - 50 = DELTA T 70F
BTU's for 1 gallon of water is 70 (delta T) * 8.34 (pounds per gallon) = 583.8 BTU's
Flow Rate 2 Gallons per Minute
2 Gallons * 60 minutes = 120 Gallons per hour
120 Gallons * 583.8 BTU's per Gallon = 70,056 BTU's per Hour

Solar Constant (measured outside the earth's atmosphere by satellite) is about 1.3 kilowatts (1,366 watts) per square meter (kW/m²)
The maximum value is about 1 Kw (1,000 watts) per sq meter, measured at the earth's exposed surface, when the sun is directly overhead.

Solar Insolation Maximum sun energy (irradiance) reaching the surface of the earth over a given time period.

kWh (kiloWatt hour) to BTU examples:
1 kWh = 3,412 btu's (per square meter when the sun is directly overhead)
90,000 btu's x 0.00029307108 = 26.37 kWh

Correct Flow Rates for Evacuated Tube Collector

0.026 to 0.066 Gallons per Minute per Tube
0.1 to 0.25 Liters per Minute per Tube

Volume Equivalents

231 CUBIC INCHES PER GALLON

7.481 GALLONS PER CUBIC FOOT

1.02 GALLONS PER 100' OF ½" PIPE

2.29 GALLONS PER 100' OF ¾" PIPE

4.08 GALLONS PER 100' OF 1" PIPE

Energy Conversions

1 kWh (kilo watt hours) = 3412.1415 BTU's

1 BTU = 0.00029307108 kWh

Btu Content of Common Energy Units

  • 1 barrel (42 gallons) of crude oil = 5,800,000 Btu
  • 1 gallon of gasoline = 124,000 Btu (based on U.S. consumption, 2008)
  • 1 gallon of diesel fuel = 139,000 Btu
  • 1 gallon of heating oil = 139,000 Btu
  • 1 barrel of residual fuel oil = 6,287,000 Btu
  • 1 cubic foot of natural gas = 1,028 Btu (based on U.S. consumption, 2008)
  • 1 gallon of propane = 91,000 Btu
  • 1 short ton of coal = 19,988,000 Btu (based on U.S. consumption, 2008)
  • 1 kilowatthour of electricity = 3,412 Btu

Formulas

DELTA T = TEMPERATURE DIFFERENCE BETWEEN TWO VALUES (100F-90F = 10F DELTA T)

C TO F CONVERSION (C*1.8) + 32 = F

F TO C CONVERSION (F - 32.0) / 1.8 = C

LBS * 0.453592 = KILOGRAMS

KILOGRAMS * 2.204623 = POUNDS

GALLONS * 3.785412 = LITERS

LITERS * 0.264272 = GALLONS

QUARTS * 0.946353 = LITERS

LITERS * 1.056688 = QUARTS

 
Mouse Over the Image Above for a LARGER View of the SkyCam Picture
Updated Every 15 Minutes

iwalani2

Check the progress of Phil's Tundra Kit Plane

peterswood

Paintings, Artwork and Blog of Dr. Amy Peters Wood.

peterswood

Building the 65' schooner "Janet May"