Waste Heat Recovery Industrial Workshop - June 27, 2017 

If you are serious about minimizing losses on a steam plant utilizing natural gas, the only sensible way is to use the combined cycle (CC) system, reaching overall efficiencies above 61% General Electric aero derivative gasturbines have an efficiency over 42%. They are coupled with a bottoming exhaust gas fed simple cycle steam plant having an efficiency of about 35%. 42 + 0.35 (100 - 42) = 62.3 The economies are much better, when the operational costs ( maintenance, operation, repair) are considered. Do we still drive Stanley Steamer cars? The supply of NG is increasing. The option of coal gasification is also realized (CGCC), Abundant fuel for hundreds of years of cheap energy is there. There are still abundant opportunities to improve gasturbines using high temperature CMC's (ceramic matrix composites) further raising the CC thermal efficiencies and vastly improving long term reliability. Environmental concerns are minimized when considering the clean exhaust gases, which consists of N2 and 2 H2O molecules for every CO2 molecule , at efficiencies approaching 70% ( still way below the limiting Carnot efficiency) this approach is by far the most reasonable.

Really great lecture~! Helpful for me, thanks for sharing👏

In order for a civilization, such as ours, to become energy independent, it would be necessary to have complete control over waste heat. This would require the ability to harness waste heat and convert it into a usable form of energy. Most likely this is not possible using convention methods of heat differential and sensible heat transfer technologies bound by thermodynamic laws. But some laws can be circumvented if not outright broken when consideration of latent heat of vaporization is taken into account. Water for example, has a very high latent heat of vaporization around 940 BTU per pound. This amount of energy can be absorbed through a phase change without any change in sensible heat. This however renders the use of heat exhangers ineffective, as the temperature differential remains zero, even though a substantial amount of heat energy has been absobed during this phase change. In order to extract this heat of vaporization, concentration of latent heat of vaporization must take place, and no heat exchange method can be used to achieve this. It must be a spontaneous transfer to a lower state of entropy resulting in this ability to extract waste heat. And this can be achieved by saturation of air with water. Air has an affinity for water and can be spontaneaously saturated to a high 90-95 % relative humidty. This causes the absoption of large amounts of sensible heat to be converting into latent heat of vaporization (phase change). The temperature of the water reservoir has now decreased by the 940 BTU per pound of evaporated water and cools this reservoir. The sensible heat of the liquid water decreased. The latent heat of the water vapor and air mixture has been increased by the same 940 BTU per pound +/- the actual sensible heat of the liquid water reservoir. Now this latent heat must be converted into sensible heat through compression of the air/water vapor mixture. Compression of high energy gases into a confined space causes latent heat to be converted into sensible heat during this process. This mixture when compressed to as little as 2 to 3 times atmosphric pressures can be converted into kinetic energy in a supersonic nozzle. We have now been able to achieve a 60-70 % conversion of the sensible heat and pressure energy in the converging diverging nozzle into a supersonic flow of kinetic energy. This would allow a pure impulse style turbine (reaction turbine is ineffective) to absorb the kinetic high energy flow of air and condensate into mechanical and subsequently electrical energy. Similar to a heat pump, high COP levels can be achieved at very low waste heat levels of 70 F and up. in this example we have an open cycle system similar to a brayton cycle where the heat sync and source are in fact the same reservoir and no heat exhangers are used to convey the transfer of heat. But a phase change was used to absorb and then concentrate a small amount of "waste" heat into high differential sensible heat with only sufficient compression to achieve the ability of supersonic expansion (2X atmospheric pressure at the throat of a CV/DV nozzle). 100 years ago we made a choice to go high pressure, low speed, laminar flow, reactionary turbines...... This was a mistake.

Is there a waste heat recovery in air conditioning systems? If yes what are the possible applications to convert the waste heat into usable energy?

😴 good lecture to help with sleeping

Very insightful😊

B t most of the boilers that We have installed has minimum efficiency of 90% with out economizer. I don't know why you have mentioned only 75% efficiency on your presentation.

How is it possible these methods were not applied when designing these plants? Oh right yea, back then gasoline was cheaper than air

can i gotb PPT of this workshop