16:00
Session 5C: Waste Heat - ICEs
Chair: Stéphane Watts
16:00
20 mins
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Experimental Investigation of a Low Pressure Steam Rankine Cycle for Waste Heat Utilization of Internal Combustion Engines
Christoph Laux, Andreas Gotter, Matthias Neef
Abstract: High heat losses via exhaust gas and coolant in internal combustion engines (ICE) are the basis for numerous investigations regarding downstream processes for power generation. The most promising concepts are Organic Rankine Cycles (ORC) and Steam Rankine Cycles (SRC).
In previous work of the Center of Innovative Energy Systems, Düsseldorf (Germany), the technical and economic feasibility of a low pressure SRC has been investigated and the advantages in comparison to organic Rankine cycles are highlighted. A distinctive feature of the cycle is the use of the ICE coolant heat for evaporation, which limits the cycles maximum steam pressure to values below atmospheric pressure. This work presents first results of a test rig with data reconciliation according to DIN 2048 to validate the simulation results and design calculations.
As a basis for the experimental investigations, a gas fired CHP plant was selected. The design of the test rig is optimized for the operation in the laboratory, where the coolant heat is emulated by a tempering device and the exhaust heat of the CHP plant is emulated by a gas burner. With the designed test rig, it is possible to control the volume flow and the temperatures of the coolant and exhaust gas, so that different load conditions of the gas fired CHP plant can be investigated. For initial tests, the turbine in the SRC is replaced by a throttle to achieve the pressure drop of the turbine.
The experimental results show, that the exhaust and coolant heat of a 36 kWel CHP plant can be emulated and the performance expectations of the cycle can be met in stable steady-state conditions. Based on the measurement results and the turbine design calculations an electric power output of the cycle of 3.8 kW will be possible, which results in a cycle efficiency of about 6.5 % and an increase of the electrical power output of the CHP plant of about 10 %. The results show that the plant concept is technically feasible and, with further optimization, also represents an alternative to ORC plants in terms of increasing the efficiency of a cogeneration plant.
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16:20
20 mins
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Gas Turbine Design and Matching Research of Waste Heat Recovery System for Marine Diesel Engine
Jiewei Peng, Zijan Zhang, Zhichao Gu, Peijun Qin
Abstract: With the emphasis on energy and environmental protection, energy-conservation and emission-reduction become vital issues for industrial development. Moreover, with the development of legislations on marine environment, the marine diesel engine has become a focus of energy saving and emission reduction for ships. For low-speed diesel engines under high load, waste heat from exhaust gas can be recovered by the compact and efficient gas turbine.
In this paper, the matching design research between low speed diesel engine and gas turbine is carried out. To balance efficiency and compactness, the impeller was adjusted and generated by ANSYS BLADEGEN, based on 1D thermodynamic design. And the 1D calculation is similar to the CFX simulation result: the total-static efficiency is 73.8% compare to 76.7%.
Moreover, the flow separation was happened at the impeller suction side and created vortex which is mainly due to the high incidence angle. The non-design operating point simulation of the turbine shows though the pressure ratio increase will cause the efficiency decline a little, the total shaft power rises.
In sum, this paper worked out a power turbine suitable for a low-speed diesel engine according to the turbine character matching design and simulation, which provides foundation to the construction of a steady operation waste heat recovery system for marine diesel engine.
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16:40
20 mins
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Research on Transient Response Character Analysis of ORC Waste Heat Recovery System for Marine Diesel Engine
Jiangnan Liu, Zijian Zhang, Jingfen Li, Zhichao Gu, Jinyong Feng
Abstract: Nowadays, maintaining the wholesomeness of the oceans, protectingthe marine environment have become common norms for all the people in the world to abide by, and a collective mission for all mankind to undertake. The EEDI and EEOI index had already been stated by IMO and phased on due course so as to reduce the CO2 emission. Decreasing the emission from Marine diesel engine as the main power of the civil ships is the main key to achieve the purpose of reducing pollution.
Organic Rankine Cycle, which have been proved to be one of the most efficient low temperature waste heat recycle system for power generation by now, can utilize the
xhausted gas from diesel engine to drive the power generator and thus lower the EEDI along with increasing the fuel efficiency. However, the steady output of the ORC waste heat recycle system have long been disturbed by the unstable working condition of diesel engine coursed by the mutable sailing environment.
This thesis had investigated the heat sources character of different type of diesel engine and their several working conditions, therefore, established the system model of ORC waste heat recovery system for marine diesel engine and researched the working condition of the cycle system which influenced by internal and external disturb. Then, the thesis worked on the transient response character effected by factors such as thermal inertia、evaporating pressure、evaporating temperature at multi time scale. Results how: the higher the load of the diesel engine, the more stable of the energy generated; the
larger the thermal inertia, the dully system response. Eventually, with various system response character summarized, the thesis provides support data for the control system to improve the adaptability of the ORC waste heat recycle system applying to the vessel.
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17:00
20 mins
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Theoretical Analysis of an ORC-VCR Based Air Conditioning System by Heat Recovery of Jacket Coolant
Youcai Liang, Zhibin Yu
Abstract: Waste heat recovery of engine has been taken as a most potential way to reduce the fuel consumption of vehicles. The thermal energy contained in jacket water is usually ignored due to its low temperature. In this paper, a combined cycle based on an organic Rankine cycle (ORC) integrated with a vapour compression cycle (VCC) has been proposed to produce cooling for vehicle cabin by heat recovery of engine jacket water. In this system, the power generated in ORC is used to drive the VCC compressor. R134a was used as refrigerant in refrigeration cycle, different ORC working fluids were studied and compared. The results suggest that the concept is thermodynamically feasible and the heat contained in jacket water is sufficient for ORC-VCC system to provide enough cooling for a coach more than 40 seats, which could significantly enhance the performance depending on part-load of the engine. However, possible challenges during transient operations as well as issues related to scalability and reliability require further investigation.
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