PERPINDAHAN PANAS HYBRID PHOTOVOLTAIC DAN THERMOELEKTRIC GENERATOR DENGAN HOT MIRROR

Heat transfer is the transfer of energy from one area to another due to the temperature difference between these areas. Wasted heat energy can be converted into electricity using (TEG) between the hot and cold sides. If the temperature difference is more significant, the efficiency may increase along with the operating temperature of the TEG-type material. So in this study, the author will calculate the heat transfer that occurs in Photovoltaic (PV), Thermoelectric Generator (TEG), and Hot Mirrors by utilizing thermal energy light produced from Muxindo LED bulbs with 10 Watt, 15 Watt, and 20 Watt power. The results of this study indicate that by using 10, 15, and 20 Watt LED bulbs for free convection heat transfer, the power generated from each point increases because it passes through several obstacles from objects that experience a decrease in temperature to PV and TEG, with the characteristics of the displacement. The movement of molecules from the medium importance follows convection heat at every point of transfer in the intermediate substance. The most significant power generated from radiant heat transfer is about 0.1873 Watt. It occurs on the surface of the fresnel lens using a 20 Watt LED bulb with the characteristic that the radiation propagates in a straight line and does not require an intermediate medium to transfer heat from one substance to another. The most significant conduction heat transfer power, 0.2453 Watt, occurs in Fresnel Lens using a 20 Watt LED bulb with heat transfer characteristics in solid objects.

Designing & Analysis of Supercapacitor Hybrid Battery System with Regenerative Braking

This work implements the help of a super capacitor hybridized with a battery pack to power a motor to work an electric bike. The supercapacitor of specification is built in combination with the battery pack to work in pair at instances where more load in needed. For example in situations like accelerating, decelerating, and climbing a slope. The supercapacitor is recharged while in motion using two different technologies: 1. Regenerative Braking and 2. Generator incorporated into wheel hub. Regenerative braking is an energy recovery mechanism that slows down a moving vehicle or object by converting its kinetic energy into a form that can be either used immediately or stored until needed. In this mechanism, the electric traction motor uses the vehicle's momentum to recover energy that would otherwise be lost to the brake discs as heat. This contrasts with conventional braking systems, where the excess kinetic energy is converted to unwanted and wasted heat due to friction in the brakes, or with dynamic brakes, where the energy is recovered by using electric motors as generators but is immediately dissipated as heat in resistors. In addition to improving the overall efficiency of the vehicle, regeneration can significantly extend the life of the braking system as the mechanical parts will not wear out very quickly. The system uses Faradays Law of Electromagnetic Induction to induce an EMF and generate voltage by passing a current carrying conductor through a rotating magnetic field. Using this implementation, it has been noted that the battery life has been increased significantly and the total range of the bike has also increased considerably. Keywords: Batteries, Battery pack, Supercapacitor, Hybrid power system, Dynamo mechanism

Sustainable Self-Cooling Framework for Cooling Computer Chip Hotspots Using Thermoelectric Modules

The heat generation from recent advanced computer chips is increasing rapidly. This creates a challenge in cooling the chips while maintaining their temperatures below the threshold values. Another challenge is that the heat generation in the chip is not uniform where some chip components generate more heat than other components. This would create a large temperature gradient across the chip, resulting in inducing thermal stresses inside the chip that may lead to a high probability to damage the chip. The locations in the chip with heat rates that correspond to high heat fluxes are known as hotspots. This research study focuses on using thermoelectric modules (TEMs) for cooling chip hotspots of different heat fluxes. When a TEM is used for cooling a chip hotspot, it is called a thermoelectric cooler (TEC), which requires electrical power. Additionally, when a TEM is used for converting a chip’s wasted heat to electrical power, it is called a thermoelectric generator (TEG). In this study, the TEMs are used for cooling the hotspots of computer chips, and a TEC is attached to the hotspot to reduce its temperature to an acceptable value. On the other hand, the other cold surfaces of the chip are attached to TEGs for harvesting electrical power from the chip’s wasted heat. Thereafter, this harvested electrical power (HEP) is then used to run the TEC attached to the hotspot. Since no external electrical power is needed for cooling the hotspot to an acceptable temperature, this technique is called a sustainable self-cooling framework (SSCF). In this paper, the operation principles of the SSCF to cool the hotspot, subjected to different operating conditions, are discussed. As well, considerations are given to investigate the effect of the TEM geometrical parameters, such as the P-/N-leg height and spacing between the legs in both operations of the TEC mode and TEG mode on the SSCF performance.

On the Design of an ORC Axial Turbine Based Expander Working As a Mechanical Driver in Gas Compressor Stations

In this work, the feasibility of increasing the capacity of a natural gas compressor station by means of an Organic Rankine Cycle (ORC) is studied. In the proposed configuration, the ORC recovers natural gas compressor drivers’ wasted heat and converts it into mechanical energy. Thus, as innovative approach, the ORC generated mechanical power will be used to drag an additional gas compressor. A case study representative of a medium-size on-shore facility is taken as reference. The mechanical drivers’ arrangement is composed of four recuperated GTs of PGT5 R type (three units continuously operating and one used as back-up) and two smaller engines of Solar Saturn 20 type. Assuming the actual operation of the station, the addition of an ORC, as bottomer cycle, is designed to recover the exhaust heat from the three PGT5 R running units. According to the Authors’ preliminary investigations and state of the art MW-size parameters, a regenerative sub-critical ORC cycle is selected. Therminol 66 and Hexamethyldisiloxane (MM) are chosen as intermediate and working fluids, respectively. The design ORC key cycle parameters are identified: about 2700 hp (2 MW) of capacity could be added to drive a compressor. For a comprehensive investigation, ORC off-design operating range is explored too assuming one out of three topper cycle units out of service. Since a direct coupling of the ORC driver and the gas compressor is expected, thus excluding the use of gearboxes to avoid losses, an ORC axial turbine based expander is designed that accommodates variable speed operation. The referred design includes mean-line calculations and three-dimensional computational fluid dynamics (CFD) based numerical simulations at design and off design point conditions.

Heat Pipes Heat Exchanger for HVAC Applications

With increasing global demands for energy (especially in developing countries), energy production will increase, the wasted energy will increase, and the emission and pollution will increase also. That makes the researchers focus on recovering the wasted heat and enhancing the recovery devices to improve the energy-saving amount. Heat pipe technology is one of the promising methods of transfer heat efficiently between two species. There are three common types of heat pipe; conventional heat pipe, thermosyphon, and oscillating heat pipe. Each type contains three sections: evaporator, adiabatic, and condenser section. The heat pipe as a heat exchanger was investigated and experimentally used by many authors to recover the wasted energy in many engineering applications.

Si and SiGe Nanowire for Micro-Thermoelectric Generator: A Review of the Current State of the Art

In our environment, the large availability of wasted heat has motivated the search for methods to harvest heat. As a reliable way to supply energy, SiGe has been used for thermoelectric generators (TEGs) in space missions for decades. Recently, micro-thermoelectric generators (μTEG) have been shown to be a promising way to supply energy for the Internet of Things (IoT) by using daily waste heat. Combining the predominant CMOS compatibility with high electric conductivity and low thermal conductivity performance, Si nanowire and SiGe nanowire have been a candidate for μTEG. This review gives a comprehensive introduction of the Si, SiGe nanowires, and their possibility for μTEG. The basic thermoelectric principles, materials, structures, fabrication, measurements, and applications are discussed in depth.

Thermodynamic Concepts on Efficiency of Aircraft Engines

Along with the development of engine technology to be able to produce maximum efficiency in aircraft jet engines, various modifications were made to the machine tools. Modifications are made by taking into account four main factors, namely: maximum power output, reduced engine weight, low fuel consumption and maximum aircraft payload. This research uses a meta-analysis method, namely the analysis of several research results in line with what has been done previously regarding the efficiency of aircraft jet engines. The thermodynamic concept related to the heat engine which implements the brayton cycle that maximum efficiency can be done by reducing wasted heat energy and maximizing the work produced. From this concept, several attempts to maximize aircraft efficiency, such as modification of design that have a significant impact on weight reduction, fuel barrier design with low fan pressure, high bypass design ratio are also carried out in an effort to reduce aircraft noise levels. Aircraft noise levels can also be minimized by modifying the nozzle and ejector on the engine.

Optimal Load Allocation of Compressors Drivers Taking Advantage of Organic Rankine Cycle As WHR Solution

Natural gas demand is projected to continue growing in the long-run and the gas distribution networks are intended to expand with it. The gas compression, along the pipeline, is usually performed in centrifugal compressors driven by gas turbines. In a typical installation, a significant portion of primary energy introduced with natural gas is discharged into the atmosphere with gas turbine exhaust gases, as wasted heat. Since the important investment of the last years, it is of major interest to study solutions for compressor stations, in order to reduce the primary energy consumption and the operative costs. A promising way to enhance the process efficiency, achieving the aforementioned goals, involves recovering compressors drivers wasted heat and converting it into mechanical or electrical energy through an Organic Rankine Cycle (ORC). In this study, the feasibility of adding additional compressor capacity inside the station, with the help of an ORC, as waste heat recovery technology, is studied. In particular, the Authors propose a procedure to identify the bottomer cycle optimal size and to re-define the optimal distribution of driver’s loads inside the station. The strategy consists in the resolution of a minimum constrained problem, such as the loads are re-allocated between gas turbines and ORC, in order to minimize the fuel consumption of the station. Constraints of the problem are the load balance of the system and the regulation limits of each units. The objectives are: (i) to identify the optimal sizes for ORC and electric motor driven compressor to be installed; (ii) to redefine the optimal distribution of the loads based on an annual operating profile of compressors; (iii) to quantify the environmental savings in terms of CO2 avoided compared to the original set-up of the facility; (iv) to assess the economic feasibility in the presence of additional aspects, as, for example, a carbon tax. A typical interstate gas compressor station, with about 24 MW of mechanical drivers installed is taken as case study. Results of the study show that, for the investigated case study, the optimal ORC size turns out to be close to 5.3 MW, which correspond to an additional compressor power consumption of 4.8 MW that can be provided to the ORC driven compressor. Thus, resulting ORC design allows to produce — via an electric motor generator, connecting the ORC and the user — the 18 % of the yearly station mechanical energy demand. A reduction of 22 % of CO2 emissions, compared to the original arrangement is achieved. The economic feasibility of the proposed solution turns out to be very dependent on the natural gas cost and on the carbon tax, if applied. As expected, higher prices lead to higher avoided costs, thus to higher saving and lower payback periods (4 years), whilst low gas prices and no carbon tax can increase the payback period up to 20 years.