A comparative study of sustainable industrial heat supply based on economic and thermodynamic factors

Abstract

Three different process types of heat supply for industrial production processes requiring low temperature heat at 140°C are analyzed and compared with each other. The thermodynamic and economic efficiency of a gas turbine process with a heat recovery boiler (GT), a gas and steam turbine combined cycle process with a back-pressure turbine (GT-CC) and a high temperature heat pump (HTHP) system recovering waste heat from humid exhaust air between 90°C and 50°C are assessed based on energy flows, exergy flows and costs of heat provided as 4 bar (abs) saturated steam. The economic analysis bases on the comparison of the consumption-related costs of heat, the capital-related costs of heat and the operation-related costs of heat. The payback-times are calculated for different HTHP investment cost levels (1000 EUR/kWQ, 750 EUR/kWQ, 500 EUR/kWQ and 250 EUR/kWQ). To evaluate the effects of fluctuating energy costs, a sensitivity analysis with varying gas and electricity prices has been carried out.

Keywords

• heat pump
• gas turbine
• combined heat and power
• pulp and paper industry
• wärmepumpe
• gasturbine
• kraft-wärme-kopplung
• papierindustrie