Estate for years. An estate for years is one which is to continue for a definite period fixed in advance by. agreement between landlord and tenant. The name is somewhat misleading because the period may be for less. than a year, measured in specific days, weeks, or months. Estate from period to period. An estate from period to period (or periodic tenancy) is one which continues for. periods of time (typically year-to-year, month-to-month, or week-to-week) as designated by landlord and tenant. in their agreement. The most common periodic tenancy is the month-to-month tenancy.
You will still require 8.34 BTU to raise the temperature of a gallon of water one degree F. 1  I say approximately because the weight of water varies slightly with its temperature. 2  Water is at its densest at 4 degrees Celsius (39 degrees F). 3  A gallon of water at temperatures above and below that value will weigh less.
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/mÂ²) 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.