Carnot battery: Simulation and design of a reversible heat pump-organic Rankine cycle pilot plant

Eppinger, Bernd; Steger, Daniel; Regensburger, Christoph; Karl, Jürgen; Schlücker, Eberhard

doi:10.1016/j.apenergy.2021.116650

Cited by 49 publications

(13 citation statements)

References 23 publications

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“…For a clearer and more uniform presentation of the results, reference conditions for the simulation are chosen, which refer to the working machines of the PTES, i.e., the HP (see Table 1), the sensitive thermal storage (see Table 2) and the ORC (see Table 3). The reference case is a direct result of the optimizations of the former studies presented by Eppinger et al in 2020 [24] and the design goals of Eppinger et al in 2021 [33]. Quantities of the high-pressure side of both cycles (condensation temperature in the HP process, sub-cooling temperature in the HP process) are initial values and are calculated during the simulation to fit the chosen pinch point temperatures in both cycles.…”

Section: Reference Casementioning

confidence: 99%

Simulation of the Part Load Behavior of Combined Heat Pump-Organic Rankine Cycle Systems

et al. 2021

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Pumped Thermal Energy Storages (PTES) are suitable for bridging temporary energy shortages, which may occur due to the utilization of renewable energy sources. A combined heat pump (HP)-Organic Rankine Cycle (ORC) system with suitable thermal storage offers a favorable way to store energy for small to medium sized applications. To address the aspect of flexibility, the part load behavior of a combined HP-ORC system, both having R1233zd(E) (Trans-1-chloro-3,3,3-trifluoropropene) as working fluid and being connected through a water filled sensible thermal energy storage, is investigated using a MATLAB code with integration of the fluid database REFPROP. The influence on the isentropic efficiency of the working machines and therefore the power to power efficiency (P2P) of the complete system is shown by variation of the mass flow and a temperature drop in the thermal storage. Further machine-specific parameters such as volumetric efficiency and internal leakage efficiency are also considered. The results show the performance characteristics of the PTES as a function of the load. While the drop in storage temperature has only slight effects on the P2P efficiency, the reduction in mass flow contributes to the biggest decrease in the efficiency. Furthermore, a simulation for dynamic load analysis of a small energy grid in a settlement is conducted to show the course of energy demand, supplied energy by photovoltaic (PV) systems, as well as the PTES performance indicators throughout an entire year. It is shown that the use of PTES is particularly useful in the period between winter and summer time, when demand and supplied photovoltaic energy are approximately equal.

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Section: Reference Casementioning

confidence: 99%

Simulation of the Part Load Behavior of Combined Heat Pump-Organic Rankine Cycle Systems

et al. 2021

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“…The working fluid is R1233zd(E) as it is advantageous in terms of safety and performance [4]. An overview of the pilot plant is shown in [11] and therefore it is not presented here in detail. The experiment is divided into two sections: first, the loading of a thermal storage is operated (HP mode); hereafter, the unloading procedure (ORC mode) takes place.…”

Section: Experimental Set-upmentioning

confidence: 99%

Heat Exchangers in Carnot Batteries: Condensation and Evaporation in a Reversible Device

et al. 2021

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The combined heat pump–organic Rankine cycle is a thermal–electrical storage concept which allows the reversible use of components in both operation modes (loading and unloading the storage). This saves in terms of investment costs but also creates challenges during design and operation. A heat exchanger is an expensive component destined to be used for the reversible purposes of a heat pump condenser and an organic Rankine cycle evaporator. In this study, the operation of such an apparatus was evaluated based on an analytical model, experimental data and thermal imaging. This study shows that the model can predict the filling of the apparatus distinguished by liquid, vapour and the two-phase region. The thermal imaging supports the model and gives the location of the regions. Connecting both methods, a valid statement about the current condition of the heat exchanger is possible. Due to very small pinch points, the apparatus is not efficiently used in the investigated modes. Extending the pinch to 2 K can already save up to 46.1% of the heat exchange area. The quality of the heat transfer in the evaporator (q˙ORC = 10.9 kW/m2) is clearly higher than in the condenser (q˙HP = 6.1 kW/m2).

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“…To establish a low-carbon society, dependence on fossil fuel should be avoided. To reduce the use of fossil fuel, the new processes such as unused heat recovery, 1,2) promotion of renewable energy utilization, [3][4][5][6][7] and improvement in various process efficiencies have been required. In these processes, the key technology is heat exchanger.…”

Section: Introductionmentioning

confidence: 99%

Long-term Experiment of Hot Spring Heat Recovery Using Rotary Heat Exchanger by Controlling Precipitation

Maruoka

Yamamoto

Endo³

et al. 2022

ISIJ Int.

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To establish a low-carbon society, it is necessary to break away from dependence on fossil fuels, and the utilization of geothermal energy/waste heat is one of the key methods. When using geothermal energy, the rate of heat transfer decreases with time due to the precipitation of scale on the heat transfer surface, and periodic maintenance is required. Therefore, the running cost of utilizing geothermal energy is high. We focused on a rotary heat exchanger consisting of a rotating cylinder as the heat transfer wall and a fixed blade attached to the rotating cylinder for scraping the heat transfer surface. In this study, the heat recovery characteristic from chloride hot spring was experimentally evaluated. The results showed that scale formation on the heat transfer surface could be suppressed and the heat transfer characteristics could be maintained for one month.

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Carnot battery: Simulation and design of a reversible heat pump-organic Rankine cycle pilot plant

Cited by 49 publications

References 23 publications

Simulation of the Part Load Behavior of Combined Heat Pump-Organic Rankine Cycle Systems

Simulation of the Part Load Behavior of Combined Heat Pump-Organic Rankine Cycle Systems

Heat Exchangers in Carnot Batteries: Condensation and Evaporation in a Reversible Device

Long-term Experiment of Hot Spring Heat Recovery Using Rotary Heat Exchanger by Controlling Precipitation

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