Varun Goel

Heat transfer and friction characteristics of an equilateral triangular solar air heater duct using inclined continuous ribs as roughness element on the absorber plate

An experimental study has been carried out to determine the effect on the heat transfer and friction characteristics of an equilateral triangular solar air heater duct using inclined continuous ribs as roughness element on the absorber plate. The experimental study encompasses the range of Reynolds numbers from 5600 to 28,000, relative roughness height (e/Dh) 0.021–0.043, relative roughness pitch (p/e) 8–16 and angle of attack (α ) 30–60°. The duct has an aspect ratio (W/H) of 1.15. The effect of flow parameters and roughness parameters on heat transfer and friction factor is discussed. The thermohydraulic performance parameter has been determined for the given range of flow parameters and roughness parameters.

Solar Air Heaters with Thermal Heat Storages

Solar energy can be converted into different forms of energy, either to thermal energy or to electrical energy. Solar energy is converted directly into electrical power by photovoltaic modules, while solar collector converts solar energy into thermal energy. Solar collector works by absorbing the direct solar radiation and converting it into thermal energy, which can be stored in the form of sensible heat or latent heat or a combination of sensible and latent heats. A theoretical study has been carried out to rate the various thermal energy storage commonly used in solar air heaters. During the investigations rock bed storages have been found to be low type thermal heat storage, while phase change materials have been found to be high heat thermal storages. Besides this, a few other heat storing materials have been studied and discussed for lower to higher ratings in terms of thermal performance purposely for solar heaters.

A Technical Note on Fabrication and Thermal Performance Studies of a Solar Pond Model

A solar pond has been fabricated to analyze the thermal behavior of it, in the climatic conditions of Moradabad, Uttar Pradesh. Sodium chloride (NaCl) has been used to form a salt gradient for better performance, and a dark-colored (blackened) rigid surface bottom with 1 mm irregularities has been considered for trapping the heat in a good amount. A solar pond with a surface area of 2.56 m2 and a depth of 1 m has been filled with salty water of various densities to form three salty water zones (upper convective, nonconvective, and heat storage). A few investigations have been carried out to evaluate the thermal efficiencies of three different zones of the solar pond. An attempt is also made to improve the thermal performance of the salt gradient solar pond.

Effects of dual biofuel approach for total elimination of diesel on injection system by reciprocatory friction monitor

Biodiesel is a promising fuel which shows potential and gradually received attention as a best alternate feedstock for diesel engine. Previous investigations have shown that use of double biofuels in a diesel engine can be a promising aspect for complete elimination of diesel from compression ignition engines which will decrease our dependency on fossil fuels. The tribological performance of injection system is primarily based on the lubricity characteristics of the fuel. So, it is imperative to a more diversified research about the impact of using double biofuels in engine. In the present investigation, different biodiesel-oil blends were investigated using the ASTM D6079 by the reciprocatory friction monitor. The effect of temperature variation on lubricity characteristics was also studied. The biodiesel-oil blends shows improvement in results as compared to diesel. Biodiesel is prone to oxidation due to availability of unsaturation in their moieties. The effects of oxidation on lubricity characteristics were also studied. It was also found that the operating conditions collectively affected the lubricity characteristics of tested feedstocks.

Water Footprints of Hydropower Projects

As the world is shifting towards renewable energy power generation it becomes important to explore the correct picture of renewable energy technologies. Today every nation is ramping up investments in power sector and trying to increase its installed capacity of power generation through renewable energy due to benefits like less greenhouse gas emissions, less environmental impacts etc. associated with it. But at the same time it is being observed that it is important to assess the renewable energy technologies to find out their real environmental impacts. Among all renewable energy sources, hydropower is becoming the most popular and promising source throughout the world. The power generation through hydropower is solely depends on the availability of water resources so formation of large dams and reservoirs are associated with establishment of a hydropower plant. The effects of climate change affect the water resources throughout the world as well. Large scale reservoirs can be found as key players for low carbon and sustainable society in future. Consequently, it becomes important to assess the consumption of water from hydropower generation in terms of water footprints. This chapter reviews the estimation of water footprints of hydropower plants through different methodologies and come out to the conclusion that there is still requirement of an effective methodology for water footprints calculation of hydropower projects.

Effects of VOCs on Human Health

With broad commutability of pollutants, air pollution is a complicated issue that intimidates directly to human health and our environment. Various indoor and outdoor air pollution comprises of regulated and unregulated emissions. Volatile organic compounds (VOCs) are one of them which are carcinogenic and lead to photochemical reactions. Emissions of VOCs are directly associated with large number of industrial processes, emission through transportation, and various indoor and outdoor sources. Due to deleterious effect of different VOCs emitted from transportation, chemical industrial plants and from indoor on the environment make their eviction mandatory or at least degrade them under the limit set by environmental norms. So, it has turned a burning topic to diminish air pollutants and set a norm for volatile emissions. This study focuses on the major sources of carbonyl and aromatic compounds in indoor and outdoor environment. Some remedial processes like photocatalytic oxidation, plasma decomposition, chemisorption, and catalytic oxidation have been described in this study through which decomposition of these contaminants can be achieved. This chapter contains a deep study on health effects from the carbonyl and aromatic compounds.

Solar Food Processing and Cooking Methodologies

In this study, a theoretical analysis of food processing (e.g., solar drying), worldwide cooking pattern, and cooking methods by using the solar energy has been reviewed. Solar food processing method is applied as direct absorption, air heater, and a combination of direct and indirect drying by solar radiation. Therefore, this process is one of the most accessible and hence the most widespread processing technologies. Traditional solar drying involves keeping products in the direct sunlight. Solar drying and cooking processes take place at different temperatures and timescales, and it depends on the nature of the food or substance. The amount of solar energy that reaches to the system and design parameters determines the performance of food processing and cooking systems. The time duration of drying and cooking depends on the temperature of heated air and environment. The temperature distributions, mass, and ingredient of food have an important role in the performance of dryers and cooker boxes. For a better understanding of the system parameters, the concept of solar food processing has been discussed thermodynamically. Energy saving by using solar systems has also been discussed.

Life Cycle Assessment of an Academic Building: A Case Study

Abstract With the advent of human population the need for energy consumption is growing every second. Due to these growing demands, energy production has reached to unprecedented levels. These in turn lead to great losses to environment in the form of various pollutants. With Kyoto protocol target obligations, quantification along with the reduction in greenhouse gas (GHG) emissions at the national level is an urgent requirement. Buildings are also one of the major sources of energy consumption and contributors of GHG emissions throughout their life cycle. Various studies based on life cycle assessment (LCA) have been carried out to assess the consumption of energy and environmental impacts allied with buildings. The present chapter deals with LCA of an academic building located at hilly terrain to quantify energy consumption along with GHG emissions. The obtained results are also compared with another LCA study to see the effects of location and climate change on energy consumption and GHG emissions.

Computational Study of Various Longitudinal Fin Profiles

In this paper, a computational study of longitudinal fins of different profiles has been carried out. For this purpose, various fin profiles have been modeled in CATIA and the further simulations were carried out in ANSYS Fluent. The present research is focused on the performance parameters of fins such as temperature distribution, fin effectiveness, and fin efficiency for different fin geometries. The values obtained from the CFD software have been compared with the theoretical values to validate the results. Also an attempt has been made to compare the weight and cost associated so as to develop a strong basis for the selection of fins.