Reversible Heat Pump–Organic Rankine Cycle Systems for the Storage of Renewable Electricity

Abstract

Storage of electricity from fluctuating renewable energy sources has become one of the predominant challenges in future energy systems. A novel system comprises the combination of a heat pump and an Organic Rankine Cycle (ORC) with a simple hot water storage tank. The heat pump upgrades low temperature heat with excess power. The upgraded heat can drive an Organic Rankine Process using the heat pump in reverse operation mode. This approach allows a comparably efficient storage of excess electricity. Waste heat sources usually do not qualify for electricity production even with ORC processes due to low temperatures. Upgrading the temperature of the waste heat by means of excess electricity makes the use of an ORC feasible in order to recover the electricity input. Thermodynamic cycle simulations with IPSEpro software outline that the process provides power-to-power efficiencies in a range of 50% for small-scale applications based on commercially available heat pump components. The isentropic efficiency of compressors/expanders plays a crucial role on the system performance. Applications of the proposed cycle in the megawatt range with more efficient turbines and dynamic compressors will therefore increase the power-to-power efficiency to above 70%.

Energy Consumption Optimization through Dynamic Simulations for an Intelligent Energy Management of a BIPV Building

“…Thus, for this purpose, the modeling process incorporates and explores the interaction of the thermal and electrical elements in the building. Similar work focusing on the modeling process and optimization of HVAC systems and energy consumption can be found in [26], [27], [28], [29], and [30].…”

Multi-Criteria Economic Analysis of a Pumped Thermal Electricity Storage (PTES) With Thermal Integration

“…The resulting layout has been already investigated from the thermodynamic point of view in previous studies (Frate et al, 2020), and it can be considered as a standard for TI-PTES systems based on organic fluids. More advanced architectures may be found in literature (as in Staub et al, 2018;Dumont et al, 2019), but here only the standard one is investigated for the sake of simplicity. The investigated TI-PTES layout is reported in Figure 1.…”

“…Several authors investigated the TI-PTES performance with different operating fluids, often using the same fluid for both HT-VCHP and ORC. TI-PTES performance with R365mfc is investigated in Staub et al (2018), butene in Jockenhöfer et al (2018) and Steinmann et al (2019), and R1233zd(E) and R1234yf in Dumont et al (2019). An extensive comparison between 17 fluids is performed in Frate et al (2017a), and R1233zd(E) was found to be the one with the highest efficiency among those with low GWP.…”

“…In Kim et al (2013), nearly isothermal compression and expansion are introduced by means of liquid piston compressors and expanders. Several different thermal storage technologies can be found in the literature: one-tank thermocline sensible heat storage (Staub et al, 2018), two-tanks sensible heat storage (Frate et al, 2020), several-tanks in series sensible heat storage (Morandin et al, 2012a,b), hybrid sensible/latent heat storage (Jockenhöfer et al, 2018;Steinmann et al, 2019), purely latent heat storage (Frate et al, 2017a), and underground geothermal heat storage (Ayachi et al, 2016).…”

“…A detailed mapping of TI-PTES performance was performed by Dumont et al (2019), and several other authors investigated the TI potentiality (e.g., Jockenhöfer et al, 2018;Staub et al, 2018;Steinmann et al, 2019).…”