Ads
related to: btu radiator size calculator square feetsmartholidayshopping.com has been visited by 1M+ users in the past month
Search results
Results From The WOW.Com Content Network
Measured in square feet, the reference standard for EDR is the mattress radiator [1] invented by Stephen J. Gold in the mid 19th century. One square foot of EDR is able to liberate 240 BTU per hour when surrounded by 70 °F (21 °C) air and filled with steam of approximately 215 °F (102 °C) temperature and 1 psi of pressure.
In the United States and Canada, the R-value that describes the performance of thermal insulation is typically quoted in square foot degree Fahrenheit hours per British thermal unit (ft 2 ⋅°F⋅h/Btu). For one square foot of the insulation, one Btu per hour of heat flows across the insulator for each degree of temperature difference across it.
Although the concept of U-value (or U-factor) is universal, U-values can be expressed in different units. In most countries, U-value is expressed in SI units, as watts per square metre-kelvin: W/(m 2 ⋅K) In the United States, U-value is expressed as British thermal units (Btu) per hour-square feet-degrees Fahrenheit: Btu/(h⋅ft 2 ⋅°F)
For premium support please call: 800-290-4726 more ways to reach us
kelvin square-metre per watt (K⋅m 2 /W or, equally, °C⋅m 2 /W), whereas the I-P (inch-pound) unit is degree Fahrenheit square-foot hour per British thermal unit (°F⋅ft 2 ⋅h/BTU). [13] For R-values there is no difference between U.S. and Imperial units, so the same I-P unit is used in both.
The radiant exitance (previously called radiant emittance), , has dimensions of energy flux (energy per unit time per unit area), and the SI units of measure are joules per second per square metre (J⋅s −1 ⋅m −2), or equivalently, watts per square metre (W⋅m −2). [2] The SI unit for absolute temperature, T, is the kelvin (K).