Examination of Efficient Operation Method of ATES System by Comparison Operation with WTES System of Existent Heat Storage System

Aquifer thermal energy storage (ATES) system is widely used mainly in Europe and USA. In this paper, we examined the efficient operation method of ATES by comparing it with the water thermal energy storage (WTES) system of an existent thermal energy storage (TES) system using simulation. This study uses three aquifers: pumping wells, thermal storage wells, and reducing wells. The initial temperature is 19.1 °C groundwater from the surrounding area. ATES systems use the same operating methods as WTES systems to reduce heat storage efficiency and increase energy consumption. The operation that combines the ATES system with the pre-cooling/pre-heating coil can be used for air conditioning operation even if the heat storage diffuses or the pumping temperature changes. The aquifer heat storage system was used for the pre-cooling/pre-heating coil, and the cooling power consumption was reduced by 20%. The heating operation could not maintain heat for a long time due to the influence of groundwater flowing in from the surroundings. Therefore, it is recommended to use the stored heat as soon as possible. When energy saving is important by introducing a pre-cooling/pre-heating coil, the operation is performed by storing heat at a low temperature close to geothermal heat and also using groundwater heat. In addition, if the reduction of peak power in the daytime is important, it is appropriate to operate so that the heat stored in the pre-cooling/pre-heating coil is used up as much as possible. As a result, it was found that it is effective to operate the ATES system in combination with a pre-cooling/pre-heating coil. In cooling operation, ATES-C1-7 was the lowest at coefficient of performance (COP) 2.4 and ATES-C2-14 was the highest at COP 3.7. In heating operation, ATES-H1-45 was the lowest at COP1.2, and in other cases, it was about the same at COP2.4-2.8. In terms of energy efficiency, the heating operation ATES-H1-45 had a low energy efficiency of 4.1 for energy efficiency ratio (EER) and 3.9 for seasonal energy efficiency ratio (SEER). In other cases, the energy efficiency was 8.2–12.4 for EER and 8.7–15.3 for SEER.

Analysis of Deformation and Stresses of a Lightweight Floor System (LFS) under Thermal Action

The lightweight floor system (LFS) with a heating coil is one of many types of radiant heating systems. It differs from most of the others, as it has a much higher thermal efficiency at low flow temperature. To verify whether adhesive mortars can safely connect the ceramic floor with the insulating substrate, the deformations and stresses values of all light system layers under thermal action should be checked and compared to their maximum strengths. For this purpose, an LFS test field was conducted using the strain gauges and digital measurement techniques, and floor displacements and deformations were determined. The results obtained from the tests were confirmed by finite element method calculations. It was also found that the stress of each floor component was much lower than their strength. This proves that the LFS with a heating coil, without metal lamellas, meets the safety regulation for use. The results of the analysis can be useful in the design of heated/cooled LFSs.

Nominal Operating Envelope of Pod and Pen Style Electronic Cigarettes

Many Electronic Nicotine Delivery Systems (ENDS) employ integrated sensors to detect user puffing behavior and activate the heating coil to initiate aerosol generation. The minimum puff flow rate and duration at which the ENDS device begins to generate aerosol are important parameters in quantifying the viable operating envelope of the device and are essential to formulating a design of experiments for comprehensive emissions characterization. An accurate and unbiased method for quantifying the flow condition operating envelope of ENDS is needed to quantify product characteristics across research laboratories. This study reports an accurate, unbiased method for measuring the minimum and maximum aerosolization puff flow rate and duration of seven pod-style, four pen-style and two disposable ENDS. The minimum aerosolization flow rate ranged from 2.5 to 23 (mL/s) and the minimum aerosolization duration ranged from 0.5 to 1.0 (s) across the ENDS studied. The maximum aerosolization flow rate was defined to be when the onset of liquid aspiration was evident, at flow rates ranging from 50 to 88 (mL/s). Results are presented which provide preliminary estimates for the effective maximum aerosolization flow rate and duration envelope of each ENDS. The variation in operating envelope observed between ENDS products of differing design by various manufacturers has implications for development of standardized emissions testing protocols and data reporting required for regulatory approval of new products.

Grid-Scale Ternary-Pumped Thermal Electricity Storage for Flexible Operation of Nuclear Power Generation under High Penetration of Renewable Energy Sources

In this work, the integration of a grid-scale ternary-Pumped Thermal Electricity Storage (t-PTES) with a nuclear power generation to enhance operation flexibility is assessed using physics-based models and digital real time simulation. A part of the electricity from the nuclear power generation is delivered to the grid, and the balance is used to power a heat pump that can be augmented by an auxiliary resistive load element to increase the charging rate of the thermal storage. This increases the thermal potential between hot and cold thermal stores (usually solid materials or molten salts inside large storage tanks). The thermal energy is transformed back into electricity by reversing the heat pump cycle. Different transient scenarios including startup, shutdown, and power change for grid-connected operation are simulated to determine the behavior of the hybrid nuclear-t-PTES system operating under variable loads that constitute a departure from conventional, baseload nuclear plant operation schemes. Ternary refers to the three modes operation: (i) heat pump (including heating coil), (ii) heat engine, and (iii) simultaneous operation of heat pump (including heating coil) and heat engine during changeover from pumping to generation or vice-versa. The controllability of t-PTES in the short timescales as a dynamic load is used to demonstrate operational flexibility of hybrid nuclear plants for flexible operation through advanced load management. The integration of t-PTES into nuclear power systems enhances the system flexibility and is an enabler for high penetration of renewable energy resources.

JUUL ‘new technology’ pods exhibit greater electrical power and nicotine output than previous devices

In 2019, JUUL Labs began marketing in the European Union ‘new technology’ pods that incorporated a new wick that it claimed provided ‘more satisfaction’. In this study, we compared design and materials of construction, electrical characteristics, liquid composition and nicotine and carbonyl emissions of new technology JUUL pods to their predecessors. Consistent with manufacturer’s claims, we found that the new pods incorporated a different wicking material. However, we also found that the new pod design resulted in 50% greater nicotine emissions per puff than its predecessor, despite exhibiting unchanged liquid composition, device geometry and heating coil resistance. We found that when connected to the new technology pods, the JUUL power unit delivered a more consistent voltage to the heating coil. This behaviour suggests that the new coil-wick system resulted in better surface contact between the liquid and the temperature-regulated heating coil. Total carbonyl emissions did not differ across pod generations. That nicotine yields can be greatly altered with a simple substitution of wick material underscores the fragility of regulatory approaches that centre on product design rather than product performance specifications.