Thermal unit requirement of grape (Vitis vinifera L.) varieties under south western Punjab conditions

Weather components have significant impact on the phenology of fruit plants. In order to study the effect of heat, photothermal and heliothermal units on phenology of grapes, an experiment was conducted during 2016 and 2017 on eleven grape varieties. The weather based indices were used for characterizing the thermal response to various phenophases of different grape varieties. Based on the thermal response the eleven varieties were classified into early, mid and late maturing categories. The fruit ripening was differed by 7-9 days for early, 4-8 days for mid and 1-3 days for late ripening groups. For early, mid and late maturing varieties the accumulated range of growing degree days was 1303-1530, 1617-1712 and 1912-1959 °C day, photothermal unit was 15971-19032, 20201-21484 and 24255-24923°C day. Likewise, minimum heliothermal unit was required by early ripening varieties i.e., Himrod(9973 °C days) and Madeliene Anguvine (11235 °C days) but, maximum for long duration varieties like Black Muscat (15000 days) and Angur Early (14579 °C days). Maximum and minimum heat use efficiency was recorded by variety Perlette (1.57) and Black Muscat (0.96), respectively.

Heat Exchanger Design and Optimization

A heat exchanger is a unit operation used to transfer heat between two or more fluids at different temperatures. There are many different types of heat exchangers that are categorized based on different criteria, such as construction, flow arrangement, heat transfer mechanism, etc. Heat exchangers are optimized based on their applications. The most common criteria for optimization of heat exchangers are the minimum initial cost, minimum operation cost, maximum effectiveness, minimum pressure drop, minimum heat transfer area, minimum weight, or material. Using the data modeling, the optimization of a heat exchanger can be transformed into a constrained optimization problem and then solved by modern optimization algorithms. In this chapter, the thermal design and optimization of shell and tube heat exchangers are presented.

Entropic Balance Conditions and Optimization of Distillation Column System

The paper considers the limitation problem of the distillation column systems separating multicomponent mixtures with serial and parallel structures. The solution takes into account the irreversibility of processes. Using entropic balance conditions, the dependence of load on heat consumption is obtained for a binary distillation column. This dependence is parameterized through two characteristic coefficients–reversible efficiency and irreversibility factor. This dependence was used to solve problems of distribution of heat and raw material fluxes in parallel column structure and selection of optimal separation order in serial structure. The obtained results make it possible to estimate the minimum heat consumption for the separation of a given flow of raw materials, the maximum productivity, and efficiency of the system.

Thermosuperrepellency of a hot substrate caused by vapour percolation

Drop rebound after collision with a very hot substrate is usually attributed to the Leidenfrost effect, characterized by intensive film boiling in a thin vapour gap between the liquid and substrate. Similarly, drop impact onto a cold superhydrophobic substrate leads to a complete drop rebound, despite partial wetting of the substrate. Here we study the repellent properties of hot smooth hydrophilic substrates in the nucleate boiling, non-Leidenfrost regime and discover that the thermally induced repellency is associated with vapour percolation on the substrate. The wetting structure in the presence of the percolating vapour rivulets is analogous to the Cassie-Baxter wetting mode, which is a necessary condition for the repellency in the isothermal case. The theoretical predictions for the threshold temperature for vapour percolation agree well with the experimental data for drop rebound and correspond to the minimum heat flux when spray cooling.

Novel Bioactive Extraction and Nano-Encapsulation

An extraction technology works on the principle of two consecutive steps that involves mixture of solute with solvent and the movement of soluble compounds from the cell into the solvent and its consequent diffusion and extraction. The conventional extraction techniques are mostly based on the use of mild/high temperatures (50–90 °C) that can cause thermal degradation, are dependent on the mass transfer rate, being reflected on long extraction times, high costs, low extraction efficiency, with consequent low extraction yields. Due to these disadvantages, it is of interest to develop non-thermal extraction methods, such as microwave, ultrasounds, supercritical fluids (mostly using carbon dioxide, SC-CO2), and high hydrostatic pressure-assisted extractions which works on the phenomena of minimum heat exposure with reduced processing time, thereby minimizing the loss of bioactive compounds during extraction. Further, to improve the stability of these extracted compounds, nano-encapsulation is required. Nano-encapsulation is a process which forms a thin layer of protection against environmental degradation and retains the nutritional and functional qualities of bioactive compounds in nano-scale level capsules by employing fats, starches, dextrins, alginates, protein and lipid materials as encapsulation materials.

Sustainable Green Building

Green building refers to a structure and employing a method that's environmentally accountable and resource economical throughout a building’s life cycle. Since buildings consume nearly five hundredth of the world's total energy, inexperienced buildings, on the other hand, consume a minimum quantity of energy with the utilization of energy economical materials. Hence, location of inexperienced buildings within the close proximity would produce an inexperienced zone and supply a far healthier setting with minimum heat island result. In India there are 2 primary rating systems for inexperienced buildings: GRIHA (green rating for integrated surround assessment), LEED (leadership in energy and setting design). Green buildings compared to standard buildings appear specifically similar and conjointly within the building use, however disagree within the operational savings and considerations for human comfort and indoor and atmosphere. inexperienced buildings get pleasure from the advantages of saving 40-50% energy by reducing greenhouse gas emissions into the atmosphere; it conjointly saves concerning 20-30% of water by victimization rain gathering or gray apply techniques. It conjointly reduces VMT (vehicle miles travelled) by selecting the placement near conveyance and conveniences that helps in reduction of petrol consumption. However, on the opposite hand, inexperienced buildings face several barriers just like the high initial investment needed for construction, split incentives.

Smoldering and Flaming of Disc Wood Particles Under External Radiation: Autoignition and Size Effect

Wildfires are global issues that cause severe damages to the society and environment. Wood particles and firebrands are the most common fuels in wildfires, but the size effect on the flaming and smoldering ignitions as well as the subsequent burning behavior is still poorly understood. In this work, a well-controlled experiment was performed to investigate smoldering and flaming ignitions of stationary disc-shaped wood particles with different diameters (25–60 mm) and thicknesses (15–25 mm) under varying radiant heat flux. The ignition difficulty, in terms of the minimum heat flux, increases from smoldering ignition to piloted flaming ignition and then to flaming autoignition. As the sample thickness increases, the minimum heat flux, ignition temperature, and burning duration for flaming autoignition all increase, while the peak burning flux decreases, but they are insensitive to the sample diameter. During ignition and burning processes, the disc particle is deformed due to the interaction between chemical reactions and thermomechanical stresses, especially for smoldering. The characteristic thickness of the smoldering front on wood is also found to be 10–15 mm. This study sheds light on the size effect on the ignition of wood particles by wildfire radiation and helps understand the interaction between flaming and smoldering wildfires.

Influence of Atomization Characteristics on Lean Blow-Out Limits in a Gas Turbine Combustor

In order to investigate the effects of atomization characteristics on the lean blow-out (LBO) performance, an experimental study was carried out on the spray and the combustion. The LBO limits and the outlet temperature near the LBO condition of different atomizers were measured in a single dome rectangular model combustor with a dual-radial and a dual-axial swirl cup, respectively. In the combustor, the spray analysis was performed on different atomizers (without combustion) at the LBO condition. The Malvern particle size analyzer was used to measure the Sauter Mean Diameter (SMD), and the laser sheet was used to take spray images. First of all, the spray pattern determines the minimum heat release required to maintain the combustion, which corresponds to the ideal LBO fuel/air ratio (FAR), which is the maximum potential for the lean combustion. Secondly, the matching of the spray SMD, the droplet size spatial distribution and the droplet initial velocity with the flow field determines the ratio of the completely burned fuel to the total fuel ejected from the atomizer, which determines the extent to which the combustor exerts its lean combustion potential. In addition, the numerical simulation of the flow field of the combustor with two structures was carried out, which provided an important basis for the theoretical analysis of this paper.

Control Process Modelling of Thermodynamic Systems Containing a Thermal Energy Storage Tank

The article content constitutes the answer to a growing interest of a heat-flow processes automatisation applied into detached houses heating sector. The paper contains a brief description of a usage of the PID and fuzzy controllers. The methods of the controller’s setting selections (e.g. Ziegler-Nichols method), which are alternative to the classical ones, have been also presented within the paper. The optimization of the controllers’ settings for the executive systems of a thermodynamic cycle is also available in the paper. It was carried out based on the minimum heat flux increase time in the condenser unit of a heat storage tank. For this purpose the Simplex Neldera- Meada algorithm was used. In the article, the results of the changeable work of the thermal energy storage tank have also been presented. The analysis was carried out in the Matlab Simulink environment.