is oil heat more expenssive than gas heat?
85279
No, not right now.  Natural gas prices have almost doubled this winter season.
1168302
Price is a local issue depending on your utility companies. However, in tems of efficiency it's got to be electric as all of the heat in the element is converted to heat in the water and less is then lost to the surroundings through the wall of the kettle than getting a flame to externally heat the kettle. The combined cycle of the gas-electricity cycle means it would still probably be more efficient to convert the gas to electricity in an efficient electricity company generator station and then to use the resultant electricity in a home.\n\nThis can be shown quite easily- put your hand over an electric kettle and feel the excess heat being given off. Now try to do that over a gas kettle!
831873
Is it referring to the heat load calulation for air con
633790
Yes, but it is not a good idea. Stick to vegetable matter. The animal fat will cost more to render into usable fuel than anything else. Cooking grease and lard from bakeries and restaurants is used for fuel, again, heating fuel needs to burn a little cleaner than industrial applications. There is also the question of particulates in the oil clogging your burner and bacteria propagation.
846365
Thermal energy IS heat.
292127
Oil would evaporate slower.  The reason is not what it has in it to make it evaporate but rather the temperature at which a substance evaporates, and how much energy is needed to maintain that temperature while it evaporates.  Vinegar is much less dense than oil and evaporates at a lower temperature and therefore requires less energy to fully evaporate than the same volume of oil.
408961
It depends on the impurities in the gas and the temperature of the gas.  If you have high chlorides and thermal cycling, you may need alloy steel.\n\nFor a pure hydrocarbon stream at less than 60°C, carbon steel would be fine.
905654
Propane is higher.  It's because C3H8 has a higher density than CH4.  There's a formula in "Perry's Chemical Engineer's Handbook" that lets you estimate the heat value of a hydrocarbon fuel, based on its density, which I don't have available right now...however, the following should be useful:\n\nhttp://cta.ornl.gov/bedb/appendix_a/Heat_Content_for_Various_Fuels.xls
776432
I am a HVAC trainer in the USA, and as such I have to explain the difference between energy (heat is a form of energy) and temperature. For the most part, my students do not posses any college background, and so I do my best to explain this in layman terms. There are chapters written on this subject, and to do it justice here …. well here goes.\n\nHeat is a form of energy, as is electricity, natural & propane gas, coil, gasoline, etc. Temperature is a measurement of how densely heat energy is packed into a substance. The more heat energy there is in a substance, the more vigorous the atoms and molecules will move. If the motion is vigorous enough, the substance can change its state and assume new characteristics (ice is different from liquid water, which is different from steam). \n\nThe temperature of a given amount of substance will increase as heat energy is added to that substance, and temperature will decrease as heat energy is taken (provided the substance does not change state). If a substance is at a temperature where it will change state, examples: ice~water @ 32deg F., …. and water~steam @ 212deg F. (at one atmosphere pressure), than the addition or subtraction of heat energy will cause the substance to change state, and the temperature will not change until the substance has finished changing state  “Sensible heat” is a form of energy that causes a change in temperature, “latent heat” energy causes a change in state.\n\n”Specific heat value” is the amount of heat energy it takes to rise or lower the temperature of one pound of a substance one degree F.  For instance, if we take one pound of ice at 0deg F., and put 1/2 BTU into that pound of ice, the temperature of that pound of ice will go up one degree F, thus .5 is the specific heat value of ice. If we continue to put energy into that ice, the temperature will go up one degree F. for every 1/2 BTU of energy we put in until it reaches 32deg F., at which time the ice will be at a temperature where it will melt if additional energy is put into it. We will have to put an additional 144 BTU’s to that one pound of ice at 32deg F., to change it into liquid water at 32deg F. \n\nOnce we have liquid water, we will have to put 1 BTU into that pound of water to raise the temperature 1deg F., thus 1.00 is the specific heat value of liquid water (please note: the specific heat value of liquid water changes slightly as the water’s temperature changes, but for most calculations, the constant “1.00” can be used). \n\nWhen the water reaches 212deg F. at one atmosphere (pressure at sea level), the water will once again be at a temperature where it can change state. As heat energy is added the liquid water, it will turn into steam. The amount of heat needed to change one pound of liquid water at 212deg F. into one pound of steam at 212deg F. is ….. ready ….. here it comes ….. 970 BTU’s …. That deserves a “wow”. \n\nThe reason I made such a big deal out of the 970 BTU’s is because it’s important that HVAC technicians and mechanics understand the concept that it takes a lot more energy to change the state of a substance than it does to change the temperature one degree Fahrenheit (or for that matter, one degree Celsius).
1186504
A.   thermal efficiency=work done/total amount of heat taken= 3200/1.55x10^4= 0.206\n\nB.  heat discarded=heat taken-work done=15500-3200=12300 J\n \nC. Heat evolved= 15500 J\nthe mass of gasoline is heat/heat evolved per gm.\n=15500/46000\n= 0.3369\n\nD. power output = 63x 3200=201600 J
56608
gas is also a better recovery time
1136153
many materials absorb better at the infrared wavelengths than the shorter wavelengths so the absorbed energy is conserved as heat.  There are materials that absorb shorter wavelengths and convert the energy to heat, such as a microwave oven???  Water absorbs at that frequency (1-2 GHz) and the water molecule resonates.  The vibrational energy is re-emitted as heat due to a Stokes shift.\n\nThe shorter wavelengths are more energetic and more capable of depositing energy that might show up as heat but it depends on the absorption of the material itself.
30165
This really depends on what liquid versus what solid you are heating.  Some liquids are actually less heat conductive that solids.\n\nFor example,  if you have some oil and some aluminum then the aluminum is going to heat up faster than the oil would.
629048
i dont think so, when a gas condenses, it gives heat to the surrounding air
786406
No. It just wastes more gas, builds up carbon deposits in the cylinders quicker, and tends to make the engine an oil burner.  There are many possible reasons why his is faster, but worse than optimum combustion isn't one of them.
177848
It depends on exactly what you are after here. Is the intention to make the point that since entropy is a thermodynamic property of the system, if the entropy of state 1 is s1 and that of state 2 is s2, then the entropy difference is s2-s1, regardless of how one transits between the states? However, in any real process there is, if one considers both the system and the surroundings, always a net increase in entropy. Of course, reversible processes are ideal constructs. In this sense the irreversible process will have the higher entropy increase.
977702
It is just like going to the bottom of a swimming pool.  The deeper you go, the more weight of water is above you.  The atmosphere also behaves as a fluid, but it is a gas.  With gases, the greater the pressure, the closer the gas molecules are to each other which means the gas has more mass per unit volume at sea level than it does at higher elevations.  Temperature in gas is due to the energy of the collisions of the gas molecules with each other.  The greater the number of collisions, the higher the energy (heat).  When gas expands the thermal energy is distributed over a larger volume which relates to a decrease in temperature.  Compressing the gas (example: a cylinder and piston) will concentrate the energy in a smaller space, elevating the temperature.  Which is why diesel engines do not require spark plugs.