Sub-ambient Temperatures Research Articles

Rapid Synthesis of Elastomers and Thermosets with Tunable Thermomechanical Properties.

Rapid, solvent-free synthesis of poly(1,4-butadiene) in ambient conditions is demonstrated by frontal ring-opening metathesis polymerization (FROMP) of 1,5-cyclooctadiene (COD). Furthermore, cross-linked copolymers with a wide range of tunable properties are readily prepared by FROMP of mixtures of COD and dicyclopentadiene (DCPD). Specifically, glass transition temperature and tensile modulus are varied from -90 to 114 °C and 3.1 MPa to 1.9 GPa, respectively, by controlling the comonomer ratio. Copolymers with subambient glass transition temperature exhibit robust elastomeric behavior, with the ability to repeatedly recover from large elastic deformations. As a demonstration of the capability of this manufacturing strategy, gradient materials are fabricated in less than a minute with spatially controlled properties for multistage shape memory actuation. This simple yet powerful manufacturing strategy enables rapid synthesis of copolymers ranging from elastomers to thermosets with precise control over thermomechanical properties.

Heat transfer characteristics of plate heat exchanger using hybrid nanofluids: effect of nanoparticle mixture ratio

Energetic and exergetic analyses of the plate heat exchanger are experimentally performed using Al2O3–TiO2 hybrid nanofluid as a coolant for sub-ambient temperature application to study the effect of nanoparticle volume ratio at various nanofluid flow rates ranging 2.0–4.0 lpm and inlet temperatures ranging 10–25 °C. The Al2O3–TiO2 hybrid nanofluids of 0.1% total volume concentration with different Al2O3–TiO2 ratios (5:0, 4:1, 3:2, 2:3, 1:4 and 0:5) are used as a coolant. Effects of nanoparticle mixture ratio, flow rate and inlet temperature on the heat transfer rate, heat transfer coefficient, pump work, performance index, and second law efficiency are investigated. Correlations are proposed to predict the Nusselt number for DI water as well as hybrid nanofluid. A maximum enhancement of around 16.91% and 4.5% are observed for convective heat transfer coefficient and heat transfer rate with Al2O3 (5:0) hybrid nanofluid along with 0.013% enhancement (insignificant) in the pump work for TiO2 (0:5) hybrid nanofluid. The maximum reduction in exergetic efficiency of 4.01% is observed for TiO2 (0:5) hybrid nanofluid. The study shows that the energetic and exergetic performances decrease continuously with the increase of the TiO2 ratio in the mixture, yielding no optimum nanoparticle mixture ratio.

Bioinspired "Skin" with Cooperative Thermo-Optical Effect for Daytime Radiative Cooling.

Energy-saving cooling materials with strong operability are desirable for sustainable thermal management. Inspired by the cooperative thermo-optical effect in the fur of a polar bear, we develop a flexible, superhydrophobic, and reusable cooling "skin" by laminating a poly(dimethylsiloxane) film with a highly scattering polyethylene aerogel. Owing to its high porosity (97.9%) and tailored pore size of 3.8 ± 1.4 μm, it can achieve superior solar reflectance (R̅sun ∼ 0.96) and high transparency to irradiated thermal energy (τ̅PE,MIR ∼ 0.8) at a thickness of 2.7 mm. Combined with the low thermal conductivity (0.032 W m-1 K-1) of the aerogel, the cooling skin exerts midday sub-ambient temperature drops of 5-6 °C in a metropolitan environment, with an estimated limit of 14 °C under ideal service conditions. Our generalized bilayer approach can be easily applied to different types of emitters, bridging the gap between night-time and daytime radiative cooling and paving the way for more cost-effective and scalable cooling materials.

Investigation of Li-Ion Batteries for Fast Charging at Low Temperature

Fast-charging of Li-ion batteries has become a major interest, since it is seen as the strategy of choice to enable a wider adoption of electric vehicles (EVs) by bringing a realistic solution to long-range transit. However, very little is known about how repeated fast-charging affects the battery performances in the long term, and how winter temperatures, more extreme in northern countries such as Canada, may impact the fast charging ability of the battery. Optimization of both the chemistry and the manufacturing parameters are needed to develop EV batteries capable of sustaining repeated fast-charging.The work was carried out during a four years project at the National Research Council of Canada, with the overall objective to get a better understanding of the parameters affecting the ability of a Li-ion battery to charge at high rate and sustain repeated fast-charging, especially at low temperatures.A first set of experiments investigated the comparative fast charging performance of a number of 18650 format commercial cells at various temperatures. Figure 1 shows a table summarizing the ability of 11 of these cells to charge under different regimes at room temperature or -10 °C. Interestingly, the variability in the results seemed to be related to multiple parameters. Also, the capability rating for fast-charging was not the same at ambient, sub-ambient or sub-zero temperatures. Best contenders were repeatedly fast-charged for 300 cycles at various temperatures. Here again the results showed differences in how the cells are able to sustain repeated fast-charging. The cells were then disassembled for an in-depth post-mortem study of the failure modes due to fast-charging. A number of degradation mechanisms were revealed, including macroscopic deterioration of the electrodes at the core of the jelly-roll, aluminum current collector corrosion, exfoliation of graphite and formation of thick SEI films at the anode surface. Figure 2 shows example of results from the post-mortem analysis.In a second set of experiments, the fast-charging performance of selected components was comparatively investigated in laboratory cells, including various active materials, separators and electrolyte formulations. In an example of results to be presented, Figure 3 displays the fast-charging capability of several cathode materials in full cells at 23 and 0 °C. LFP and NCA seem to be the best choices for fast-charging Li-ion cells at ambient temperature whereas LCO shows the lowest performances for rates over C/3. However, LFP showed some limitations at 0 °C, whereas LCO happened to be the best performing cathode. These results clearly show that even if the graphite anode bears the most significant challenges relative to fast-charging, cathode materials should not be overlooked in the optimization of fast-charging capabilities.The third set of experiments, currently being carried out, studies the effects of electrode manufacturing parameters (loading, porosity, N/P ratio) using a pilot-scale pouch cell prototyping line, and supported by model simulations.The presentation will highlight the results of all three sets of experiments, including results from simulation, electrochemical testing and post-mortem analysis, in an attempt to give the audience a comprehensive guidance towards the chemistries and manufacturing parameters of Li-ion cells better suited for fast-charging. Figure 1

Acrylic membrane doped with Al2O3 nanoparticle resonators for zero-energy consuming radiative cooling

Passive daytime radiative cooling plays a significant role in various cooling operations, which helps reducing electricity consumption and decreasing electricity demand. This work presents a new double-layered radiative cooling structure composed of a transparent dipentaerythritol penta-hexa-acrylate (DPHA) top layer, modified using Al2O3 nanoparticles (NPs) as resonators, and a metallic Ag bottom layer (DPHA@Al2O3 NPs/Ag). The DPHA@Al2O3 NPs layer is prepared through a fast photopolymerization process. The prepared DPHA@Al2O3 NPs/Ag system exhibits a solar reflectivity of 0.9465 and long-wave infrared (the so-called atmospheric transparency window) emissivity of 0.9163. The computed radiative cooling power at 27 °C can reach up to 106.43 W m−2. A subambient temperature drop of 10.35 °C is measured from 13:00 to 16:00 p.m. in Seoul, Korea, when using the proposed material as radiative cooler. Since this structure can be applied on flexible substrate, this has far-reaching implications for future applications in wearable devices.

Dynamic simulation and control of Natural Gas Liquids recovery process

As Natural Gas Liquid (NGL) recovery process produces methane-rich gas from C2+ liquids at high pressure and sub-ambient temperature, it is important to implement robust process control schemes for ensuring operating integrity and process safety. The study aims to assess a range of control schemes and their dynamic characteristics for the NGL recovery process, and to determine the most appropriate and effective process control scheme. Equipment sizing have been made through steady state modeling and equipment-specific process design, with which dynamic model for the NGL process has been constructed. Dynamic responses and safety issues are investigated for each control scheme by changing feed flowrate and composition. Emergency scenarios occurred by malfunction or local control error have been addressed with dynamic model and the control scheme selected, for improving process operability and safety in practice. The systematic implementation of control structure with appropriate actions allows to enhance sustainability of NGL recovery processes by reducing unwanted waste generation and minimizing unnecessary energy usage.

Dynamic impact of climate on the performance of daytime radiative cooling materials

By strongly reflecting solar radiation and being highly emissive within the atmospheric window, daytime radiative coolers can achieve sub-ambient temperature under direct sunlight. Radiative cooling performance is strongly coupled to specific climatic conditions since cooling efficiency is strongly affected by ambient air temperature, wind speed, and solar and ambient radiation intensity. In this paper, using a well-validated thermal model, the cooling performance of three radiative cooling materials with varying optical properties was evaluated under three distinct and representative climates. This analysis permits us to better understand the sensitivity of daytime radiative cooling materials to different climatic conditions, present strategies for selecting the ideal spectral properties of materials and investigate how to enhance cooling performance under adverse climatic conditions. It is shown that radiative cooling materials have better performance in hot and arid climates. Most radiative cooling materials exhibit the greatest response to changes in ambient radiation. Higher ambient air temperatures correspond to larger sub-ambient temperature of the surfaces, but this change is lower than that of the corresponding air temperature. Furthermore, by coupling a special optical grating window onto the surface of a radiative cooler, cooling performance can be significantly enhanced by asymmetrically reflecting incoming radiation but permitting outgoing emission. While an ideal material that only emits in the atmospheric window wavelengths presents the best performance under a large range of solar radiation, ambient radiation, and air temperature, the broadband ideal emitter exhibits higher cooling potential when coupled with the optical grating window.

CO2/N2 separation performance of Pebax/MIL-101 and Pebax /NH2-MIL-101 mixed matrix membranes and intensification via sub-ambient operation

Membrane-cryogenic hybrid process has been considered as a potential alternative for standalone CO2 separation. In hybrid process, CO2 from flue gas could be initially concentrated via membrane, and then high concentration CO2 stream is cryogenic-separated via phase change in low energy consumption. However, the sub-ambient separation performance and mechanism of membrane has been less investigated. In this work, Pebax 1657/MIL-101 and Pebax 1657/NH2-MIL-101 mixed matrix membranes have been fabricated and tested at sub-ambient condition. SEM, FITR and XRD results indicated that –NH2 has been successfully grafted to MIL101. Experimental results indicated that operating Pebax/MIL-101 and Pebax/NH2-MIL-101 at sub-ambient temperature (−20 °C) could enhance CO2 selectivity to 89.4 and 95.6, which increased by 96.5% and 145.1% compared with that at ambient condition. It indicated that Pebax 1657/NH2-MIL-101 has the potential to be used as sub-ambient membrane in membrane-cryogenic hybrid CO2 capture processes.

Exergy analysis of plate heat exchanger with graphene alumina hybrid nanofluid: experimentation

The water-based hybrid nanofluid is proposed as a cooling agent in a corrugated counter-flow type plate heat exchanger aimed at sub-ambient temperature applications. For this purpose, an experimental investigation has been done with different working fluids. Fluids considered as a coolant are DI water, alumina nanofluid, and alumina-graphene hybrid nanofluid in 80:20 nanoparticle ratio by volume with a total volume concentration of 0.01% dispersed in DI water. Various exergy related performance factors like coolant outlet temperature, coolant exergy rate, irreversibility rate, non-dimensional exergy, and second law efficiency have been considered. The influence of coolant inlet temperature and flow rate on different parameters has been investigated. Coolant outlet temperature, coolant exergy rate, irreversibility rate and non-dimensional exergy augments by 2.5%, 4.8%, 7.5% and 3.5%, respectively. While the second law efficiency degrades using nanoparticles and increasing flow rate and decreases with the coolant inlet temperature.

Exergy analysis of plate heat exchanger with graphene alumina hybrid nanofluid: experimentation

The water-based hybrid nanofluid is proposed as a cooling agent in a corrugated counter-flow type plate heat exchanger aimed at sub-ambient temperature applications. For this purpose, an experimental investigation has been done with different working fluids. Fluids considered as a coolant are DI water, alumina nanofluid, and alumina-graphene hybrid nanofluid in 80:20 nanoparticle ratio by volume with a total volume concentration of 0.01% dispersed in DI water. Various exergy related performance factors like coolant outlet temperature, coolant exergy rate, irreversibility rate, non-dimensional exergy, and second law efficiency have been considered. The influence of coolant inlet temperature and flow rate on different parameters has been investigated. Coolant outlet temperature, coolant exergy rate, irreversibility rate and non-dimensional exergy augments by 2.5%, 4.8%, 7.5% and 3.5%, respectively. While the second law efficiency degrades using nanoparticles and increasing flow rate and decreases with the coolant inlet temperature.

P.570 Effects of ginseng and ginsenosides on mutant huntingtin aggregation, cellular apoptosis, mitochondrial dysfunction and motor impairment of Huntington's disease model

The phase behavior of binary mixtures of non-crystallizable racemic poly (d, l-lactic acid) (PDLLA) and the mosquito-repellent/drug N,N-diethyl-3-methylbenzamide (DEET) was analyzed with respect to the effect of the polymer molar mass on the liquid-liquid (L–L) phase separation characteristics, by cloud-point measurements and differential scanning calorimetry. The PDLLA/DEET system shows a subambient upper critical solution temperature (UCST), with the critical temperature decreasing and critical polymer concentration increasing with decreasing molar mass of PDLLA. The obtained L–L phase separation curves were used to estimate the temperature-dependence of the interaction parameter, confirming that the enhanced miscibility of the system components in case of low molar mass PDLLA is due to increased entropy of mixing.

Roles of surfactant and polymer in drug release from spray-dried hybrid nanocrystal-amorphous solid dispersions (HyNASDs)

We prepared hybrid nanocrystal–amorphous solid dispersions (HyNASDs) to enhance the dissolution of a poorly soluble drug, griseofulvin (GF), and elucidated the roles of a surfactant, sodium dodecyl sulfate (SDS), and two polymers, HPC and Soluplus. Wet-milled suspensions containing 1:1 to 1:5 GF:polymer mass ratios, with and without SDS, were spray-dried. HyNASD formation was confirmed via DSC, XRPD, and Raman spectroscopy. In dissolution tests, due to its sub-ambient glass transition temperature, poor miscibility with GF, its inability to inhibit GF recrystallization, HPC provided HyNASDs with low supersaturation capability (≤50%) even at the highest loading (1:5) with/without SDS. Contrarily, owing to its stronger intermolecular interactions–miscibility with GF, and its kinetic solubilization–inhibition of GF recrystallization observed in desupersaturation tests, Soluplus, with SDS, in HyNASDs achieved remarkably high supersaturation (>250%). SDS provided enhanced wettability, allowing for fast supersaturation from Soluplus-based HyNASDs (~300% within 20 min), while higher Soluplus loading led to higher supersaturation.

Water activated healing of thiolene boronic ester coatings

A vinyl phenyl boronic ester (VPBE) was synthesised and cured with pentaerythritol tetrakis(3-mercaptoptopionate) (PTMP) and 3,6-dioxa-1,8-octanedithiol (DODT) to produce boronic ester polymer networks. The reversible nature of the boronic ester linkage in water provides an opportunity to investigate their intrinsic healing for a variety of crosslink densities and healing conditions. The boronic ester networks prepared here, all had sub-ambient glass transition temperatures (Tg) and therefore enhanced molecular mobility at room temperature and above. Intrinsic healing of the different networks is investigated after making scratches on the polymer surface and observing behaviour in humid environments, underwater and a hot dry environment. Underwater healing, as measured by the reduction in the size of the scratch, is extemely efficient and completely healed any surface scratches. This is compared with room temperature healing in moist environments where healing efficiency is more than 60% after 6 h. In a hot dry environment, no healing is observed. The healing mechanism is investigated using 3D profilometry, optical microscopy and fourier transform infrared spectroscopy (FTIR) which revealed that scratches become wider at the scratch rim, but more shallow over time. It is propsed that the presence of moisture at the base of the scratch facilitates a zipping up effect as the surface comes together to re-esterify.

Preliminary study of passive radiative cooling under Singapore's tropical climate

Sub-ambient cooling can be achieved through radiative coolers that selectively emit radiation within the atmospheric window (8–13 μm) to outer space and suppress absorption/emission of other wavelengths. This study explores the feasibility of adopting radiative cooling in the hot and humid climate of Singapore through both numerical and experimental approaches. A theoretical simulation based on the heat transfer balance is first proposed to obtain the cooling power of the radiative cooler considering different solar spectral irradiance and total water vapor column. The larger solar irradiance in Singapore, especially within the ultraviolet and visible light spectrum where the absorbance of the material is relatively high, could counteract its cooling effects. Moreover, the increased atmospheric radiation induced by higher humidity and temperatures in Singapore could worsen cooling performances of the radiative material. Next, experimental investigations were conducted by measuring the steady-state temperatures of two radiative coolers (photonic radiative cooler and enhanced specular reflector film) under three typical weather conditions in Singapore, namely clear, partly cloudy and cloudy skies. While both radiative coolers were unable to achieve daytime cooling performance on a clear day, the enhanced specular reflector (ESR) film with higher solar reflectance can reach sub-ambient temperatures on a cloudy day. When it comes to night-time, the steady-state temperature of the photonic radiative cooler and ESR film was about 3.5 °C and 5 °C lower than ambient, respectively.

RETRACTED: Generic method for creating waterborne coatings with sub-ambient daytime cooling–Part II: Cooling effect under real working conditions and key physical properties

Abstract Current sub-ambient daytime radiative cooling (SDRC) designs are generally evaluated in a well-insulated apparatus to suppress heat convection and conduction with the surrounding environment. In a companion study, we experimentally demonstrated that serial waterborne coatings, which combined particle scattering, sunlight-excited fluorescence, and mid-infrared broadband radiation, exhibited pronounced SDRC effects on various substrates installed on a well-designed rooftop setup under different climatic conditions. In this study, we experimentally show that the coating with yellow-green fluorescence (termed as the FR coating) can achieve meaningful SDRC under real working conditions. When applied to a concrete scale-model building, the FR coating showed a significant SDRC effect compared with other substrates installed on the rooftop cooling device and an assembled corrugated steel house. The average decrease in sub-ambient temperature under direct sunlight was 10.1 ± 1.4 °C with a maximum value of 12.4 °C under a peak solar intensity of 999 W/m2. Moreover, during the coldest day in winter, the maximum sub-ambient temperature reduction during the midday hours was 5.3 °C. The maximum difference between the lowest temperatures of the coated and uncoated scale-model buildings’ room interiors was 1.5–1.6 °C. Therefore, excessive heating energy consumption in the winter might be completely compensated for or exceeded by the cooling energy savings in the summer in areas that require both heating and cooling depending on the season. Additionally, the coating possesses excellent weather and salt spray resistance, self-cleaning capabilities, and excellent visible appearance, which are essential for practical applications.

High-performance subambient radiative cooling enabled by optically selective and thermally insulating polyethylene aerogel.

Recent progress in passive radiative cooling technologies has substantially improved cooling performance under direct sunlight. Yet, experimental demonstrations of daytime radiative cooling still severely underperform in comparison with the theoretical potential due to considerable solar absorption and poor thermal insulation at the emitter. In this work, we developed polyethylene aerogel (PEA)-a solar-reflecting (92.2% solar weighted reflectance at 6 mm thick), infrared-transparent (79.9% transmittance between 8 and 13 μm at 6 mm thick), and low-thermal-conductivity (k PEA = 28 mW/mK) material that can be integrated with existing emitters to address these challenges. Using an experimental setup that includes the custom-fabricated PEA, we demonstrate a daytime ambient temperature cooling power of 96 W/m2 and passive cooling up to 13°C below ambient temperature around solar noon. This work could greatly improve the performance of existing passive radiative coolers for air conditioning and portable refrigeration applications.

RETRACTED: Generic method for creating waterborne coatings with sub-ambient daytime cooling–part I: Optical properties and rooftop cooling effect measurements

Abstract The conventional way to fabricate current sub-ambient daytime radiative cooling (SDRC) systems is to maximally suppress the cooler's solar absorption and substantially improve its selective emissivity only in the atmospheric transparency window. This greatly limits the selection of materials and their practical applications. In this paper, an alternative method, which combines sunlight-triggered fluorescent cooling, particle scattering, and broadband infrared radiation, was presented for creating serial eco-friendly coatings with the SDRC effect with conventional cost-effective building materials. The presence of conventional fluorescent pigments in the coating composition increased the effective direct-normal solar reflectance via sunlight-excited fluorescent emissions to the level required for SDRC. When applied to various substrates, the serial coatings exhibited distinct SDRC effects under direct and strong sunlight in typical temperate monsoon climate regions such as Beijing. The observed sub-ambient temperature reduction of the coating with yellow–green fluorescence over an aluminium plate was 3.5 °C under a peak solar intensity of 996 W/m2, yielding a cooling power of 45.7 W/m2 under a peak solar intensity of 981 W/m2. Compared with the conventional cool white coatings, the large-scale application of the coating to urban surfaces is predicted to reduce a city's air temperature by approximately 1 °C and thereby decrease the Heat Island Intensity. Additionally, the method proposed in this paper was generic and expanded the SDRC design paradigm, thereby promoting SDRC as a viable energy-efficient technology.

Structure and magnetic properties of milled maraging steel powders

We demonstrate that high-energy ball milling of gas-atomized maraging steel powder followed by suitable thermal-treatment produces nanocrystalline maraging steel powders having improved magnetic properties, compared to the gas-atomized powders. Milling for five to eighthours formed powders comprised of, primarily, nanocrystalline martensite. The saturation magnetization (MS) of the milled powders ranged between ~164 Am2/kg and ~169 Am2/kg, while the intrinsic coercivity (HCI) ranged between ~4.9kA/m and ~6.7kA/m. At sub-ambient temperatures, from 60K to 390K, both MS and HCI decremented with the increment in temperature. The thermomagnetic behavior of the milled powders was somewhat reversible. At supra-ambient temperatures (500K–900K), both MS and HCI monotonically decreased with the increase in temperature. The thermally treated powders constituted nanocrystalline martensite and exhibited increment (by ~6%) in MS and decrement (~nearly halved) in HCI compared to the milled powder, i.e., the powders exhibited improvement in soft-magnetic properties.

Tailoring Low-Temperature Performance of a Lithium-Ion Battery via Rational Designing Interphase on an Anode.

Performances of lithium-ion batteries at subambient temperatures are extremely restricted by the resistive interphases originated from electrolyte decomposition, especially on the anode surface. This work reports a novel strategy that an anode interphase of low impedance is constructed by applying an electrolyte additive dimethyl sulfite (DMS). Electrochemical measurements indicate that the as-constructed interphase provides graphite/LiNi0.5Co0.2Mn0.3O2 pouch cells with excellent low-temperature performance, outperforming the interphase constructed by 1,3,2-dioxathiolane 2,2-dioxide (DTD), a common commercially used electrolyte additive. Spectral characterizations in combination with theoretical calculations demonstrate that the improved performance is attributed to the unique molecular structure of DMS, which presents appropriate reduction activity and constructs the more stable and ionically conductive anode interphase due to the weaker combination of its reduction product with lithium ions than DTD. This rational design of interphases via an additive structure has been proven to be a low cost but rather an effective approach to tailor the performances of lithium-ion batteries.

Roof-integrated radiative air-cooling system to achieve cooler attic for building energy saving

The building attic usually subjects to substantial solar heat gain and has much higher temperature compared to the conditioned living space during the day, especially in summer and in hot areas. Reducing attic temperature can reduce cooling energy consumption in buildings. However, conventional techniques such as cool roof or attic ventilation, suffer from either heating penalty in winter or limited attic temperature reduction. In this work, a new roof-integrated radiative air-cooling system is introduced, which couples radiative sky cooling with attic ventilation to reduce attic temperature. A radiative air cooler with 1.08 m2 surface area is constructed using a recently developed daytime radiative sky cooling metamaterial [Zhai et al., Science 355, pp. 1062–1066, 2017]. Experimental tests show that sub-ambient air cooling is achieved throughout 24-h day-and-night cycle in a summer day with clear sky conditions. Depending on air flow rates, measured sub-ambient temperature reductions of air are 5–8 °C at night and 3–5 °C at noon under direct sunlight, respectively. An in-house model is first developed for the radiative air-cooling system, the model is then coupled with EnergyPlus to study annual energy saving of buildings. The performance of the radiative air-cooling system is compared with three reference systems: shingle roof, attic ventilation, and cool roof. Results show that for a single-family house, attic temperature can be substantially reduced by 15.5–21.0 °C, varying with attic insulation level, compared to shingle roof on typical summer days. Compared to a shingle roof (solar reflectance 0.25, thermal emittance 0.9) residential building with attic insulations of R-30 (RSI-5.28), R-10 (RSI-1.76), and R-0.8 (RSI-0.14), the roof-integrated radiative air-cooling system can achieve annual cooling energy savings of 0.4–1.5 kWh/m2 (4.6–18.8%), 1.2–3.6 kWh/m2 (10.2–41.4%), and 3.7–11.8 kWh/m2 (26.5–76.1%) respectively.