What can be done to get a change from BTU to joule. If I'm not mistaken, the kilojoule and the BTU are almost the same value. So there should only be a minor difference in the amounts shown, yes?
Euric ----- Original Message ----- From: <[EMAIL PROTECTED]> To: "U.S. Metric Association" <[EMAIL PROTECTED]> Sent: Wednesday, 2004-05-19 16:34 Subject: [USMA:29874] kWh for gas > 2004 May 19 > RE 29846 > e-mail 29846 reports that gas is billed in kWh in the UK. > This is bad news. In the US kWh is restricted to electricity only. > I quote from SI 10-2002 American National Standard for Use of the > International System of Units (SI). > 3.4.5.1 Energy > The kilowatthour is widely used as a measure of > electrical energy, but this unit shall not be > introduced into any new fields. > > The unit to use is kilojoule or sometimes megajoule. > > Note that gas energy is billed for its higher heating value. That is > the energy delivered if all the water vapor is condensed to get out > the heat of vaporization. Residential furnaces do not condense. If > they did the metal parts would corrode. > > The 2001 ASHRAE Handbook Fundamentals lists the energy of several > substances on page 18.3 > methane higher heating value 55.533 MJ/kg > lower heating value 49.997 MJ/kg > so as you compare the cost to heat a house with gas or electricity > you get only 90% of the gas heat billed. > > In Colorado gas is billed in therms. The PUC and the gas company > do a good job of measuring the energy. Both make audits of the > energy content, correcting for temperature and barometric pressure. > Both audits use a gas chromatograph to measure how much of each > substance is in the gas. The gas is measured each month giving a > variable "Therm Multiplier" listed on the bill. For April the > Therm Multiplier was 0.8446 which is multiplied by the number of > cubic feet shown by the meter. > > This was started 7 years ago because a mountain resident said he > was being cheated because gas was delivered at low pressure. He > was right so the PUC said to correct for density. > > The billing is technically correct but they do not use joule. > The FERC writes all its rules in BTU so Colorado uses BTU (from > which therm is derived). > > Robert Bushnell PhD PE > >
