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The ideal tubular grate heater would be built like an ideal heat exchanger with as large a surface area as possible with material suitable to minimize the heaters thermal deterioration yet provide good thermal conductivity with a high airflow rate, similar to your home furnace. However the unique environment of a fireplace and the burning of ...
Also the copy is blurred up enough to give you the impression that maybe what it really means is 1.36 W −1 cm −1 K −1 and 78.6 Btu hr −1 ft −1 F −1 and a type-head that got overdue for its cleaning since the secretary had a tall heap of papers on her desk and if that is the case then the multilingual expression is perfectly ...
The therm (symbol, thm) is a non-SI unit of heat energy equal to 100,000 British thermal units (BTU), [1] and approximately 105 megajoules, 29.3 kilowatt-hours, 25,200 kilocalories and 25.2 thermies. One therm is the energy content of approximately 100 cubic feet (2.83 cubic metres) of natural gas at standard temperature and pressure .
The energy content (high or low heating value) of a volume of natural gas varies with the composition of the natural gas, which means there is no universal conversion factor for energy to volume. 1 cubic foot (28 litres) of average natural gas yields ≈ 1,030 Btu (between 1,010 Btu and 1,070 Btu, depending on quality, when burned)
In those contexts, the unit of heat capacity is 1 BTU/°R ≈ 1900 J/K. [5] The BTU was in fact defined so that the average heat capacity of one pound of water would be 1 BTU/°F. In this regard, with respect to mass, note conversion of 1 Btu/lb⋅°R ≈ 4,187 J/kg⋅K [ 6 ] and the calorie (below).
The contribution of the muscle to the specific heat of the body is approximately 47%, and the contribution of the fat and skin is approximately 24%. The specific heat of tissues range from ~0.7 kJ · kg−1 · °C−1 for tooth (enamel) to 4.2 kJ · kg−1 · °C−1 for eye (sclera). [13]
The heating value (or energy value or calorific value) of a substance, usually a fuel or food (see food energy), is the amount of heat released during the combustion of a specified amount of it. The calorific value is the total energy released as heat when a substance undergoes complete combustion with oxygen under standard conditions .
A notable example is diamond: at a temperature of around 100 K the thermal conductivity increases from 10,000 W·m −1 ·K −1 for natural type IIa diamond (98.9% 12 C), to 41,000 for 99.9% enriched synthetic diamond. A value of 200,000 is predicted for 99.999% 12 C at 80 K, assuming an otherwise pure crystal. [29]