It is a waste!

The table below illustrates the possible earnings which can be generated when using a Pressure Amplifier (PA) in a TRC (Thermal Recovery Cycle) system.

The below example is for a 50 MW power plant pilot project.

External heat source specific energy consumption: Qe: 49.700 kW
Overall electrical power output: Yel: 15.000 kW
Overall electrical power output efficiency: nel: 30 %
External heat source exhaust gas flow: Ge: 21,0 Kg/s
Recuperator hotside-in stagnation temperature: T0e2: 960 K
Recuperator hotside-out stagnation temperature: T0e1: 916 K
Air massflow through recuperator: Gr: 0,7 Kg/s
Recuperator coldside-in stagnation temperature: T01L: 367 K
Recuperator colside-out stagnation temperature: T02: 720 K
Isochoric stagnation pressure inside recuperator: P02: 257.817 N/m^2
Waste heat available for recuperation: Yr: 3.752.221 J/s
RVU power performance: Yt: 128.479 J/s
Recuperator efficiency: nr: 0,75 -
Waste heat isochoric recovery efficiency: nc: 0,02 -
Piping heat transmission loss efficiency: np: 0,95 -
Generator and electrical installation efficiency: ng: 0,90 -
Overall waste heat recovery efficiency: ne: 0,01 -
Electrical power produced from waste heat: Yg: 119 kW
Additional electrical power output performance: np: 1 %
Overall electrical power output: Yelt: 15.119 kW
Overall electrical output efficiency: nelt: 30 %
Power plant operational hours per year: hy: 8.000 h
Market price (Germany) per kWh (approximate): c: 0,12 EUR
Additionally kWh available per year: kWh: 955.881 kWh
Additional cost benefit income per year (approximately): in: 114.706 EUR/year

It is possible to save EUR 114.706 from waste heat alone (before return on installation costs, deductions and maintenance). The Return on Investment was, in this case, calculated to be realistic within 18 to 24 months after installation.

You may notice that, in this business case, we are dealing with only 1% extra generated power output. Looking at the thermal figures, the benefit from recovering all the waste heat would be an extra 6.680.050 kWh per year, giving an annual brutto income of approximately EUR 800.000.