Cost-effective energy storage is a critical enabler for the large-scale deployment of renewable electricity. Significant resources have been directed toward developing cost-effective energy storage, with research and development efforts dominated...
The thermal masses of components influence the performance of many adsorption heat pump systems. However, typically when experimental adsorption systems are reported, data on thermal mass are missing or incomplete. This work provides original measurements of the thermal masses for experimental sorption heat exchanger hardware. Much of this hardware was previously reported in the literature, but without detailed thermal mass data. The data reported in this work are the first values reported in the literature to thoroughly account for all thermal masses, including heat transfer fluid. The impact of thermal mass on system performance is also discussed, with detailed calculation left for future work. The degree to which heat transfer fluid contributes to overall effective thermal mass is also discussed, with detailed calculation left for future work. This work provides a framework for future reporting of experimental thermal masses. The utilization of this framework will enrich the data available for model validation and provide a more thorough accounting of adsorption heat pumps.
Electric clothes dryers in the US consume about 6% of residential electricity consumption. Available electric clothes dryers today are either based on electric resistance (low-cost but energy-inefficient) or vapor compression (energyefficient but high-cost). Thermoelectric dryers have the potential to alleviate the disadvantages of both through a lowcost, energy-efficient solution. This paper presents experimental results and steady state simulation of a prototype thermoelectric dryer. A thermoelectric model is coupled with a psychrometric dryer system model to design the experimental prototype. The results from the prototype are used to calibrate the model and identify important parameters that affect performance, such as relative humidity of air leaving the drum.
In this work, a novel Ground-Level Integrated Diverse Energy Storage (GLIDES) system which can store energy via input of electricity or heat and deliver dispatchable electricity is presented [1]. The proposed system is low-cost and hybridizes compressed air and pumped-storage approaches that will allow for the off-peak storage of intermittent renewable energy for use during peak times. A detailed control-volume energy analysis of the system is carried out, yielding a set of coupled differential equations which are discretized using a finite difference scheme and used to model the transient response during charging and discharging. The energy analysis includes coupled heat transfer and pressure drop analysis used to predict system losses for more accurate round trip efficiency (RTE) calculations and specific energy density (ED) predictions. Preliminary analysis of the current prototype indicates an electric-to-electric RTEE of 66% (corresponding to shaft-to-shaft mechanical RTEM of 78%) and ED of 2.5 MJ/m3 of air, given initial air volume and pressure of 2 m3 and 70 bar. The electric power output ranges from a max of 2.5 kW to a min of 1.2 kW and the output current ranges from a max of approximately 21 amps to approximately 10 amps at 120 V, 60 Hz dispatchable electricity, over a period of approximately 50 minutes. Additionally, it is shown that heat transfer enhancement to the point of a 5-fold increase in air heat transfer rates results in a near 5% improvement in RTEE (70% considering all component losses). Additional component efficiency improvements and efficiency gains due to system scale-up could see higher achievable RTEs.
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