Thermodynamic analysis of design and part-load operation of a novel waste heat recovery unit

Abstract

Organic Rankine Cycle (ORC) thermodynamic optimization is of critical importance while developing new plants. Optimization procedures may be imed at the highest efficiency as well as cost or sizing minimization. Optimization process is generally carried out for plant nominal rating. At the same time, part-load operation has to be carefully considered in case of waste heat recovery from flue gases coming from internal combustion engines or gas turbines. Gas mass flow and temperature variations are specific to this application, significantly influencing ORC plant performance. Secure prediction of part-load operation is of particular importance for assessment of plant power output, providing stability and safety and utilizing proper control strategy. In this paper design and off-design cycle simulation model is proposed. Off-design performance of the ORC cycle recovering waste heat from gas turbine unit installed at gas compressor station is considered. Major factors affecting system performance are outlined.

Efficiency of using heat pumps with various refrigerants in real steam turbine power units with PT-80 and T-250 turbines

“…Because of the constant level of HP power the specific fuel consumption for the production of heat energy is constant for each option of HP (simple HP, HP with RHE, HP with RHE and SC) and refrigerants (R12, R22, R134a) and are 104.12 g/(kW•h) and 117.91 g/(kW•h) for power units with PT-80 and T-250 turbines, respectively. The economic effect of modernization of the heating system (heating of the return network water) was calculated based on the ratio of the proceeds from the operation of the heat pump unit (heat supply) and the corresponding costs of electricity for the compressor's motor (an increase of own needs means an increase of specific fuel consumption for the production of electric energy) [25][26][27][28][29]. Computations were made using energy tariffs (heat and electricity) for PJSC "TGK-1" in 2019 (formula 4).…”