PENGARUH PANJANG KONDENSOR TERHADAP KINERJA TERMAL THERMOSYPHON

Cooling is an important activity in maintaining a large temperature of a component, both mechanical components and electronic components. Component temperature which is maintained from overheating will avoid damage. The cooling process is carried out by moving the heat produced by a component through a heat exchanger. One effective heat exchanger is Thermosyphon. This tool is able to move a number of heat through a very small surface area. Thermosyphon is a pipe that contains a working fluid, consisting of three parts, namely the evaporator section, the adiabatic section and the condenser section. The evaporator has the function of absorbing heat from the heat source and heat is released in the condenser. The process of heat absorption and release of heat is carried out by the working fluid in the pipe, when the fluid is in the heated evaporator it will evaporate towards the condenser the heat is released. The fluid which is finally from the condenser returns to the evaporator. This study aims to determine the thermal performance of the thermosyphon as a heat exchanger with condenser length variations. Thermosyphon is designed with a condenser length variation of 44 cm, 66 cm, 88 cm, 110 cm and 132 cm running with variation temperature. The results showed that, the highest thermal resistance at the shortest condenser length at 400C (140C / W) and the lowest at the longest condenser length at 1200C (10C / W). At all temperatures, all variations in the length of the condenser will increase the output power and heat flux. At the same condenser length, the higher the temperature, the greater the heat flux and output power. The process of this experiment is most effective at the length of the condenser 1.25 (132 cm) from the length of the evaporator length, because after that the value of thermal resistance and output power will experience a permanent tendency.

Thermodynamic Cycle Concepts for High-Efficiency Power Plants. Part B: Prosumer and Distributed Power Industry

An analysis was carried out for different thermodynamic cycles of power plants with air turbines. A new modification of a gas turbine cycle with the combustion chamber at the turbine outlet has been described in the paper. A special air by-pass system of the combustor was applied, and in this way, the efficiency of the turbine cycle was increased by a few points. The proposed cycle equipped with an effective heat exchanger could have an efficiency higher than a classical gas turbine cycle with a regenerator. Appropriate cycle and turbine calculations were performed for micro power plants with turbine output in the range of 10–50 kW. The best arrangements achieved very high values of overall cycle efficiency, 35%–39%. Such turbines could also work in cogeneration and trigeneration arrangements, using various fuels such as liquids, gaseous fuels, wastes, coal, or biogas. Innovative technology in connection with ecology and the failure-free operation of the power plant strongly suggests the application of such devices at relatively small generating units (e.g., “prosumers” such as home farms and individual enterprises), assuring their independence from the main energy providers. Such solutions are in agreement with the politics of sustainable development.