Krishpersad Manohar

University of the West Indies, St. Augustine | UWI · Department of Mechanical and Manufacturing Engineering

Aims: To estimate the available power that can be generated from wind on Oil and Gas production Platforms offshore Trinidad. Place and Duration of Study: Department of Mechanical and Manufacturing Engineering, Faculty of Engineering, University of the West Indies, St Augustine Campus. Data collected at a bpTT production platform offshore east coast...

In this study, the design requirements for a regional wave energy converter are identified from the analysis of 10 years of spectral data provided by nine buoys located across the Caribbean. It indicated that the average significant wave height and wave period in the Caribbean is 1.62 m and 5.91 s, respectively, while the average total theoretical...

This study conducted simulation and experimental analysis on a dual rotor horizontal axis wind turbine to determine the effect of rotor separation on its performance. An air study was conducted to optimize the turbine blades to a local climate of Trinidad, it was determined that a NACA 64-315 air foil would be the most optimum for the conditions. Q...

Thermoelectric devices use the Peltier effect which creates a heat flux between the junctions of two different types of materials. The thermoelectric module also referred to as a heat pump transfers heat from one side to the other when a DC current is applied. This study carried out the theoretical and experimental analysis of a thermoelectric air...

This study reviews the main barriers affecting wave energy harvesting globally by practitioners and developers and identified ways to circumnavigate the limitations experienced, in particular to Small Island Developing States (SIDS). Potential avenues for developers to exploit the available technology and allow them to evade barriers preventing adv...

The use of the hydraulic ram pump has been an attractive alternative in many areas in developing countries and rural areas that do not have or are located far from a reliable source of electricity. However, predicting the actual output delivery of the hydraulic ram pump poses many challenges due to the basic principle on which the hydraulic ram pum...

Many rural farming areas are located far from a reliable electricity supply; hence, obtaining a reliable source of water for crops and livestock can prove to be an expensive venture. A water pump operating on the water-hammer effect requires no external power source and can serve as an effective means of pumping water to a higher altitude once a re...

This study reviews wave energy and the design of various wave energy conversion systems, to assess the state of the industry, identify the limitations, challenges and barriers developers face and determine the applicability of it to the Caribbean region. The use of an energy dense and accessible renewable resource like wave energy in the Caribbean...

Many rural farming areas are located far from reliable electricity supply, hence, having a reliable source of water for crops and livestock can prove to be an expensive venture. A water pump operating on the water hammer effect requires no external power source and can serve as an effective means of pumping water to a higher altitude once a reliabl...

The study utilized the exhaust gas from a diesel engine to preheat water in the constructed shell and tube heat exchanger. The theoretical analysis of the heat exchanger was carried out using the Log Mean Temperature Difference (LMTD) method. The Volumetric flowrate of the water was manipulated using a valve and the resulting output temperature of...

A wind-powered reverse osmosis desalination system was proposed in order to assess the potential of the development of renewable energy powered water desalination in Trinidad. A simulation model for the prediction of the power delivered for a given value of wind speed was adopted. Based on the average wind speed data (3.5 m/s) and salinity of the f...

Nearly 80 percent of the global auto market is pushing toward a phase-out of petroleum cars and adoption of electric vehicles. If that comes to be, demand for gasoline and diesel would drop dramatically. This study carried out a survey on the adoption of electric vehicle in Trinidad and Tobago. An interview was conducted with several automobile ind...

The air we breathe is a mixture of gases and particulate solid and liquid matter. Some of these substances come from natural sources while others are caused by human activities such as our use of motor vehicles, domestic activities, industries and businesses. Air pollution occurs when the air contains substances in quantities that could harm the co...

One of the major challenges of the modern world in recent times has been how to effectively control the environmental pollution from the combustion of fossil fuels in internal combustion engines. In this study, the use of biodiesel (soybean methyl ester) as an alternative fuel in a four stroke, four cylinder diesel engine was explored and analyzed....

The use of conventional non-biodegradable building thermal insulation has resulted in environmental issues which prompted research to focus on the use of natural fibres in many regions. The thermal insulating properties of banana fibre was investigated and compared with conventional insulating materials to ascertain the use as building thermal insu...

One of the major challenges with the use of solar thermal energy is the intermittent nature. As such, present day research is geared towards energy storage systems in which thermal energy is stored during the day for later use. However, in many engineering applications there is a continuous steady demand for energy. Experiments were conducted using...

Laboratory wind tunnel made it possible to observe from a stationary position and measure the aerodynamic forces and associated parameters in a controlled environment the behaviour of objects that would normally be moving through the air. A conventional non-return type wind tunnel with one closed working section was designed, constructed and calibr...

An environmental cost benefit analysis (ECBA) was used to determine the feasibility using solar photovoltaic (PV) as an alternative power source. The capital investment cost and the cost of externalities such NOx and CO2 emissions from a natural gas power generation process were valued. The environmental impact of treating waste water was valued ba...

Strut arms contribute significantly to the overall drag in VAWT and reduces the overall power output. Four low drag air foil cross section profiles suitable for strut arm construction were simulated and optimized using the XFOIL 1.0 program. The profile with the lowest simulated drag coefficient, UWI-1, was constructed and tested in an open-circuit...

One of the major challenges with the use of solar thermal energy is the intermittent nature. As such, present day research is geared towards energy storage systems in which thermal energy is stored during the day for later use. However, in many engineering applications there is a continuous steady demand for energy. Hence, this study is focused on...

This study shows the experimental comparison between a commercial vapor compression refrigerator and a laboratory built thermoelectric beverage cooler. Tests were carried out to determine the time taken for the temperature of 325 ml of water in a glass jar to be reduced from 32 o C to below 6 o C. The result shows that in the freezer compartment of...

This study analyzed theoretically the temperature distribution and energy storage ability of a simultaneous charging and discharging concrete bed Storage System. This was achieved by first modeled a single spherical shaped concrete which was used to represent a sequence of points along the axis of the beds. A one dimensional finite difference formu...

This study developed a mathematical model from consideration of the basic phenomena of heat transfer to predict the thermal behavior of a simultaneous charging, storage and discharging system during a heating cycle. A solution to the complex mathematical model was assumed in the form of a general equation for which the constants in the equation wer...

In remote and stand alone applications, the simple straight bladed Darrieus type vertical axis wind turbine is very practical due to its simple design and low cost of construction. It has the potential to compete effectively with the more widely used horizontal axis wind turbines. This project explores a Darrieus type vertical axis wind turbine, ad...

Predicting the thermal conductivity of loose-fill fibrous thermal insulation is a complex problem, when considering the combined conduction, convection, and radiation heat transfer within a scattering, emitting, and absorbing medium. A piecewise model for predicting the overall apparent thermal conductivity of large diameter opaque fibrous material...

The wind energy resource situation in Nigeria including the estimated potential, economic competitiveness, technical assessment, cost comparison of wind energy technologies with other energy technologies, available amount of the resource, and global wind energy utilization are presented in this paper. The status of the database is discussed, indica...

The thermo-physical properties of environmentally friendly biodegradable agricultural by-products, oil palm, coconut and sugarcane fiber, were investigated for use as potential building thermal insulation. Thermal conductivity measurements were conducted on 51 mm thick, 254 mm square test specimens in accordance with ASTM C518 where the apparent th...

The increasing negative effect on the environment necessitates the search for viable biodegradable renewable materials for use as building thermal insulation. This study investigates the potential for oil palm fibre as an environmentally friendly building thermal insulation. Thermal conductivity measurements at mean test temperatures of 20 o C, 25...

Accurate prediction of the effective thermal conductivity of loose fill fibrous building thermal insulation remains a challenging issue to date. Most researchers considered the complex problem of heat transfer across a fibrous material to be the sum of heat transfer due to air conduction, solid conduction and radiation for which general empirical r...

The solar thermal energy resource situation in Nigeria including the estimated potential and available amount of the resource, are presented in this paper. The status of the database is discussed, indicating its degree of adequacy and an identification of the gaps. The National Energy Policy Document states that "Nigeria lies within a high sunshine...

An experimental study on the thermal properties of iron filings and steel-fiber-reinforced concrete for solar/thermal energy storage application is presented in this report. It takes into account the results of measurements of thermal conductivity, thermal resistivity, thermal diffusivity and the results of compressive strength, density as well as...

An experimental study on the thermal and mechanical properties of steel-fiber-reinforced concrete for solar/thermal energy storage purposes is presented in this report. It takes into account the results of measurements of thermal conductivity, thermal resistivity, thermal diffusivity and the results of compressive strength as well as thermal energy...

AbstractA review of literature on heat transfer coefficients indicated very little work reportedfor cross-flow pipe arrangement at various angles of inclination. In this studyforced airflow at 1.1 m/s and 2.5 m/s across 2 steel pipes of diameters 0.034m and0.049m were examined with pipe orientation inclined at 30 and 60 degrees to thehorizontal pos...

Four reaction beds (glass, Plexiglas, concrete and metal) exposed to solar (UV) light and coated with titanium dioxide were used for testing the degradation of Dichloroacetic Acid (DCA) in water, with concentrations of 130 ppmv, 390 ppmv and 650 ppmv. The glass-bed reactor showed the highest photonic efficiency followed by Plexiglas, concrete and m...

Energy is one commodity on which the provision of goods and services depend. Its availability and consumption rate is an economic index to measure the development of any community. In Nigeria, there is a limitation to power supply from the National grid which has adversely affected the economic and social development of the populace. This really ne...

The review of heat transfer in packed beds has been carried out with the emphasis on both experimental and theoretical techniques. It is observed that the two major modes of heat transfer, namely, conduction between the particles in the bed and convection between the flowing fluid and the particles, interact with each other. Also, in the designing...

Conjugate numerical solution of laminar forced convection for cross-flow over a cylinder with external longitudinal fins of finite thickness has been carried out. The rate of heat transfer from the fins increases and that from the free area of the cylinder marginally decreases with an increase in thickness, length, and number of fins. The rate of h...

This article reports a study on the numerical solution of simultaneous free convection inside empty freezer enclosures with four vertical surfaces as cold isothermal and conduction in the insulation around six faces of the enclosure. The air in the enclosure comes down along the four vertical cold surfaces and rises through a smaller volume away fr...

Conjugate numerical solution of laminar free convection about a horizontal cylinder with external longitudinal fins of finite thickness has been carried out. Fins alone contribute very small to the total heat transfer but they greatly influence the heat transfer from the uncovered area of the cylinder. Among the various fin parameters, thickness ha...

Wind energy is one of the fastest growing alternative energy resources being taped into worldwide. Vertical axis Darrieus ‘H’ type lift turbines have the potential to compete effectively with the more widely used conventional horizontal axis wind turbines. However, a disadvantage is when the rotor is stationary, no net rotational force arises, even...

This study investigates the potential of naturally occurring biodegradable fibers for use as building thermal insulation. The use of biodegradable building thermal insulation would alleviate the environmental problems presently associated with the disposal of currently used man-made non-biodegradable thermal insulations. The apparent thermal conduc...

Free convection cooling of a heated surface, generating heat at a uniform rate, housed in a three dimensional rectangular enclosure has been studied numerically. The effects of height, width of the enclosure and those of the heated surface have been investigated. Nusselt number increases with enclosure height and width but the rate of increase depe...

Low-cost thermal insulations produced as a byproduct of the sugarcane industry are becoming an affordable means of achieving some measure of thermal comfort in buildings located in developing countries. Environmental concerns about solid waste provide additional motivation for the use of sugarcane fiber as a thermal insulation. Naturally occurring...

Three thermal probes were constructed in accordance with ASTM D 5334 and calibrated using heat-flow metre data. The temperature-time response of the thermal probes for determining apparent thermal conductivity X under transient state conditions was logged at 1 s intervals. The instrumentation used reduced the determinate error associated with volta...

Apparent thermal conductivity, Λ, measurements were conducted on sugarcane and coconut fiber specimens using LaserComp “FOX 304” and Holometrix “Rapid-k” heat-flow meters. Both heat-flow meters were built and operated in accordance with ASTM C 518. The Λ measurements for sugarcane and coconut fiber were investigated over the density ranges 70 to 12...

Cost is one of the major factors to be considered when choosing a thermal insulator. Design engineers continuously strive to provide the best at the lowest possible cost. In the tropics climatic conditions are essentially hot and humid and a cause for daily discomfort. To some extent, air-conditioning of buildings has solved this problem. The major...

The thermal conductivity variation of "sharp sand" with moisture and grain size was investigated using a thermal probe method. The probe used for testing was built in accordance with ASTM D 5334 and calibrated using heat-flow meter data. Calibration tests demonstrated repeatability ± 3.5% for a 95% confidence of the dT/ d ln t slope. Experiments we...

Solar security lights are realistic solutions for tropical countries that are blessed with yearlong high intensity solar insolation. Installing a standalone solar security light is relatively simple and does not require much maintenance. In this study, a solar powered light-emitting diode (LED) security light system was designed with a single axis...

From : Dept. of Mechanical Engineering, Faculty of Engineering. Supervisor : G.S. Kochhar. Thesis (Ph. D.)--University of the West Indies, St. Augustine, Trinidad, 1998. Bibliography : l. 152-165.