When social practices produce space and create passive cooling systems in hot arid region

Practice social of people is the key to produce space and give a possibility to maintain thermal comfort and energy efficiency. The main objective of this research is to adapt the traditional strategies in the architecture actual, to achieved a thermal comfort and improve on reducing cooling load through the using of vernacular gait. Today, it is necessary to practice these systems in the current or conventional architecture of household. The study is especially for arid cities namely the region of Saoura, in the hot and dry climatic zone in Algeria, considered for this study. Two main factors is considered such as design and urban where taken into account in order to select the appropriate and specific passive cooling strategy. The results show that the passive cooling strategy of courtyard would be appropriate for arid regions, however a high thermal mass would be suitable for construction. In conclusion, this work made it possible to choose a suitable passive cooling strategy for all types of construction in hot and dry climates. Finally, this paper puts forward a set of recommendations to improve the passive design of future buildings in hot and arid climates.

Experimental study of a natural convection flow in a cubic enclosure with a partially heated inner block

In many industrial contexts, buoyancy driven flows are the only cooling strategy in case of breakdown of the forced convection cooling system. In order to study those flows in a simplified configuration, a buoyancy-driven flow is generated inside a cubic enclosure by a partially heated block (Ra = 1.4 × 109). The flow is studied experimentally in the vertical median plane, in the part of the enclosure where the flow is generated i.e. close to the heated side of the block. Velocity fields, mean profiles and RMS statistics are analyzed. The results show the presence of boundary layer flows with a central zone nearly at rest and stratified. RMS velocities are intensified with elevation.

Visualization Of Thermal Distribution During Machining of Dental Implants

Dental implants used are usually metallic. One of the most widely used materials for the same is Titanium-based alloy like Ti-6Al-4V, which suffers difficulty processing and machining due to its thermo-physical properties. The thermo-physical property of the material plays a significant role in the biocompatibility and safety to use them as dental implants. Due to its hardness and difficult-to-machine characteristics, a large amount of heat gets generated while machining, creating dimensional error. Hence before assembly of parts, they must be processed so that stress deformation of the assembly due to heat can be avoided. During machining of Ti-6Al-4V, the cooling strategy needs prior information on the thermal field, and hence, the distribution of temperature in the material is an essential domain to study. To understand the thermal distribution in the material during machining, 3-dimensional heat diffusion equations have been solved using a Finite Difference scheme coupled with the Liebmann method to generate the thermal distribution in the material. An efficient parallelized code for the same has been written in MATLAB and utilized in this numerical study. This study reveals the variation of the temperature gradient with time and space, all along with the three orthogonal directions, which will be helpful for the scientists, engineers, and surgeons to ascertain the sustainability [1, 2], suitability, and longevity of the implants.

Evaluation of different cooling management strategies for lactating Holstein × Gir dairy cows

Heat stress negatively impacts production, reproduction, and health of ruminants and strategies to alleviate these losses are warranted. Therefore, 4 experiments evaluated different cooling strategies on vaginal temperature (VT) of Holstein × Gir cows. Experiment 1 compared different amounts of water (2- or 4-L) over a 1-hour period from 1000 to 1100 h and 1600 to 1700 h. Experiment 2 evaluated the effects of sprinkling duration (in hours; 1- or 2-H), whereas Exp. 3 evaluated the effects of water amount (4- or 8-L) applied for 1- or 2-H. Lastly, the effects of a cooling strategy on specific hours of the day, starting at either 0700 (T-1) or 1100 h (T-2; Exp. 4), were evaluated. In all experiments, 12 Holstein × Gir cows were used in a 2 × 2 Latin Square Design containing 2 periods of 6 days each. Temperature and humidity index (THI) were recorded hourly and VT was recorded every 10-min throughout the experiments. As expected, an hour effect was observed for THI (P < 0.0001), which peaked early in the afternoon. In Exp. 1, a treatment × hour interaction was observed (P < 0.0001) for VT, as animals assigned to receive 4-L had a reduced VT at 1100, 1600, 1700, and 2300 h (P ≤ 0.03). During the cooling applications, cows receiving 4-L for 1 hour had a reduced VT from 60 to 150 minutes (P ≤ 0.04). In Exp. 2, a treatment × hour interaction was observed (P < 0.0001) for VT, as animals assigned to receive 4-L of water for 2-H had a reduced VT at 1200 h (P = 0.05). Moreover, during the cooling process, VT was reduced for 2-H cows from 140 to 170 min after the beginning of the cooling process (P ≤ 0.05). In Exp. 3, animals assigned to receive 4-L+2H had a reduced VT at 1200, 1700, 1800, and 1900 h (P < 0.001). A treatment × hour interaction was observed (P < 0.0001), as VT was reduced for 4-L+2-H cows from 130 to 180 min after the beginning of the cooling process (P ≤ 0.05). In Exp. 4, by the time when the first cooling cycle of T-1 was applied (0700 h), T-1 cows consistently had (P ≤ 0.05) a reduced VT up to the hottest hours and greatest THI of the day (1400 and 1500 h). This pattern was maintained until the end of the last cooling cycle, whereas T-2 cows had a reduced VT. In summary, 4 L of water over a 5-min cycle for a period of 2 hours twice a day maintained VT of Holstein × Gir cows at lower levels. Moreover, the hour at which the first cooling cycle starts also should be considered when evaluating the efficacy of a cooling strategy for an entire day.

Energy Minimisation in a Protected Cropping Facility Using Multi-Temperature Acquisition Points and Control of Ventilation Settings

Energy management in protected cropping is critical due to the high cost of energy use in high-tech greenhouse facilities. The main purpose of this research was to investigate the optimal strategy to reduce cooling energy consumption, by regulating the settings (opening/closing) of either vents or curtains during the day, at the protected cropping facility at Western Sydney University. We measured daily changes in air temperature and energy consumption under four treatments (open/closed combinations of vents and shade screens) and developed an optimal cooling strategy for energy management using multi-temperature acquisition points at different heights within a greenhouse compartment. The optimal treatment (vents open/curtains closed) reduced energy load at the rooftop, thereby maintaining a desirable plant canopy temperature profile, and reducing cooling energy. Daily energy consumption was lowest for vents open/curtains closed (70.5 kWh) and highest for vents closed/curtains open (121 kWh). It was also found that delaying the operation of opening and closing of vents and curtains until the plant canopy temperature reached 25 °C reduced cooling energy consumption and decreased heating energy consumption in the morning (e.g., 08:00 to 10:00). The estimated savings of 1.83 kWh per 1 °C cooling between the optimal (vents open/curtains closed) and least optimal (vents closed/curtains open) conditions had the potential for significant energy savings at 494 kWh per °C over a crop cycle of nine months in warm weather conditions. However, selection of the optimal cooling strategy utilising control of vents and curtains must also account for the impact from other greenhouse environmental factors, including light, humidity, and CO2 concentration, which may be crop specific.

Increasing the safety against scuffing of additive manufactured gear wheels by internal cooling channels

The layer-by-layer principle of the additive manufacturing (AM) technology of Laser-Powder-Bed-Fusion (LPBF) creates new opportunities in the design and manufacturing of efficient gear components. For example, integrating a cooling system can increase the safety against scuffing or reduce the amount of required lubrication and thus the splashing losses. Quenched and tempered steels or case-hardened steels are commonly used in the fabrication of gear components. However, the availability of these alloys for LPBF processing is still limited. The development of suitable LPBF metal gears (with a Gear Research Centre (FZG) type A geometry) out of quenched and tempered 30CrNiMo8 steel with internal cooling channels shows the possibility of significantly increasing the safety factor against scuffing. This work includes the development of a suitable cooling strategy, material development, the setup of a suitable test infrastructure and the analysis of the LPBF gears tested for scuffing.

Analysis of in-vessel accident progression in VVER1000 NPP during SBO accident with external reactor vessel cooling method

In this study, the MELCOR v1.8.6 code was utilized to perform an analysis of the in-vessel accident progression in VVER1000 reactor during the Station Black-Out (SBO) accident with and without external reactor vessel cooling (ERVC) strategy. The analysis presented the predictions of the main phenomena during the accident such as failure of fuel cladding, collapse of lower core support plate, relocation of core debris to lower plenum and mass of debris components in lower plenum, and provided comparisons between two cases in term of main parameters such as integrity time of reactor and structure components of molten pool. These parameters are very important inputs for further research on the application of external vessel cooling strategy for VVER1000 reactor.