Advanced Exergoeconomic Analysis of Organic Rankine Cycle Waste Heat Recovery System of a Marine Power Plant

Abstract

In this paper, superheated and saturated vapor ORCs commonly utilized as waste heat recovery systems of a marine power plant are investigated. First, a parametric study with different organic fluids has been carried out by applying conventional exergy and exergoeconomic analyses to the system considered in order to identify the best possible operating conditions and also to evaluate the findings of conventional exergy-based analyses. Then, advanced exergy and exergoeconomic analyses have been performed on ORCs by splitting exergy destruction rates, exergy destruction costs and investment costs of components and overall system to identify avoidable parts of costs and exergy destructions. Finally, decision criteria were suggested on the selection of more appropriate system depending on the results of the analysis.

Evaluating the Cost-Benefit of a Waste Heat Recovery Energy System With Exergoeconomics

“…Exergy is the available work potential of a system while it interacts with its environment (Cengel and Boles, 2015) as shown in Figure 1 (Bejan et al, 1996;Koroglu, 2018). This approach shows the quality of the energy and each j stream has its exergy with respect to the reference environment as (Bejan et al, 1996): Each system or process that includes exergy streams, requires the balance of the exergy streams with respect to the fuel-product approach as ( Koroglu and Sogut, 2017):…”

“…The efficiency of an energy system could be increased in several different ways. However, waste heat recovery (WHR) is a proven and available technology to harness excess energy, which is dissipated from the different heat sources of an energy system, mainly the exhaust due to having relatively high temperature and thus energy potential (T. Koroglu and Sogut, 2017). It has a potential to improve the system by 20% (Mahmoudi, Fazli and Morad, 2018;Sprouse III and Depcik, 2013).…”

“…Shu et al investigated an ORC WHR system that is designed based on four weeks of data of a ship and applied thermal and economic analyses (Shu, Liu, Tian, Wang and Jing, 2017). Koroglu and Sogut applied exergy and exergoeconomic analyses to two conceptual WHR ORCs with different working fluids and resulted that saturated ORC is a better solution with R141b as working fluid in the light of the analyses (T. Koroglu and Sogut, 2017).…”

“…The assumptions about the system are like 30 years of lifetime, 6% of the investment cost is the operation and maintenance costs, yearly working hours are 6720 h (T. Koroglu and Sogut, 2017), as the beginning of September 2018 the price of the fuel is 450 $/t ("Current price development oil and gas -DNV GL," n.d.), and 15% of the interest rate. The exhaust gases are assumed that they behave as air at 1 bar pressure.…”

Waste Heat and Water Recovery System Optimization for Flue Gas in Thermal Power Plants

“…The heating curves of ORCs can be better matched to the temperature profiles of waste heat sources, resulting in higher cycle efficiencies and higher thermal power recovery ratios than steam bottoming cycles [13]. Over the years, the ORC has been applied to waste heat recovery from different heat sources [14,15] which have also included automobile engines [16] and power plant flue gas. Koc et al [17] analyzed a geothermal ORC from an energy and economical point of view.…”