| GEM | Green Energy Model | CCS | Carbon Captures Storage |
| GDP | Gross Domestic Product | ηfurn. | Efficiency of fired heater (dimensionless) |
| S | Surface heat loss in kCal/hr m2 | NHV | Net heating value of fuel kCal/kg |
| Ts | Hot surface temperature in ˚C | ηb | Boiler efficiency in % |
| Ta | Ambient temperature in ˚C | r1 | Radius of pipe m |
| Hs | Total heat loss kCal/hr | r2 | Radius of pipe after insulation m |
| β | The mass percentage of the pollutant in monoxides form | L | Pipe length m |
| ϕ | The molar mass ratio of the oxidized to the non-oxidized form of the pollutant | x | Insulation thickness m |
| TTFT | Flame temperature ≈ 1800˚C | Mpol | Rate of pollutants released kg/h |
| TSTACK | Stack temperature ≈ 160˚C | Qfuel | Actual rate of combusted fuelkCal/h |
| CCU | Carbon Captures Utilization | Qproc. | Estimated rate of combusted fuel kCal/h |
| O.C. | Annual Operating Cost $/y |
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