Stirling engine ltd pdf

Also, to help you understand the different types of Stirling engines and how they work. The Stirling engine is a closed cycle heat engine. It is typically completely sealed from the outside environment and works on the expansion and compression of the gas typically air that's enclosed in the sealed engine. Fuel does not move through the engine like in a conventional internal combustion engine.

This means that there is no intake or exhaust. One side of the engine is heated and the other side is cooled. This causes the gas to go through cycles of expansion and compression.

This means it can produce motion by converting heat energy directly into kinetic energy or mechanical work. Remember no fuel goes through the motor because it is completely sealed from the outside. There are many types of Stirling engines. There are high pressure engines that are used commercially. There are restored low pressure engines that are used for display.

There are table top model engines built by hobbyists and students. You can find models or kits for almost all of the configurations of Stirling engines including LTD Low Temperature Differential engines.

An LTD can run on the heat of the palm of your hand. The Stirling is traditionally classified as an external combustion engine. Although, properly applied, any heat source will work to power a Stirling engine. This means that the heat source is not limited to combustion only. English Wikipedia user Andrew. Heat engines are typically accepted as Stirling engines. However, there are many types of heat engines or external combustion engines designed by many other inventors. Some of these use steam as a gaseous working fluid.

Others use high pressure water confined in a way to keep it from transitioning to steam. YK Times at en. Many Stirling engines have a gas pressure inside them that is nearly equal to the outside atmospheric pressure.

There is a fixed mass of gas, typically air, helium or hydrogen. When you heat the outside of the engine the gas expands and pushes the piston out. When you cool it, the gas compresses and the piston is pushed back in by the outside atmospheric pressure. This converts heat energy into mechanical energy or work. It relates a heat engine with a solar dish collector in order to produce electricity.

A second type of solar-powered Stirling engine was patented by NASA on August 3, which employed the use of solar energy in order to freely pump water from a river, lake, or stream.

This apparatus consists of a large dish aimed at the sun to reflect the rays into the focus point, which is located at the center of the dish as shown in figure 1 [3]. Solar energy is then collected in the form of heat to fuel a Stirling cycle engine, which operates by letting heat flow from a hot source to a cold sink in order to do work.

Typical operation is between and rpm depending on the temperature ratio. The controller requires an external power source for monitoring temperatures, starting the engine, and logging and displaying run data.

Today as a result of public concern about noise, air pollution and energy conservation there has in the recent years been increasing interest in Stirling engines micro combined heat and power units. Pictorial view of solar powered stirling engine 1. At that point, the heating part of the cylinder was placed. As the stirling engine is a closed cycle engine, cylinder is sealed with working fluids normally air, hydrogen or helium. It also consists of power piston which was tightly sealed and the displacer which is very loosely fitted so that air can move freely between the hot and cold sections of the engine.

Like most heat engines, stirling engine cycles through four main process: heating, expansion, cooling and compression [1]. This is accomplished by moving the gas back and forth between hot and cold end of the cylinder. As the hot end is in thermal contact with thermal energy from solar radiation and cold is in thermal contact with external heat sink.

So, when the gas is on the hot side, it is heated so it expands and vice versa. As a result, difference in temperature arises between two ends of cylinder or at the extremities space of displacer causing a corresponding change in gas pressure between them, which results in the motion of the displacer causing the gas to alternatively expand and compress. When the displacer is near the top of the cylinder, most of the gas is in the lower section and will be heated by the heat source and it expands.

Also, when the displacer is near the bottom of the large cylinder; most of the gas is in the upper section and will cooled and contract causing the pressure to decrease. In both the cases, the displacer just moves the air back and forth from the hot side to the cold side but does not operate the crankshaft and the engine [4].

In other words, the connecting rod to the displacer could be a string in this engine and it would still work. Figure 2. Schematic diagram of stirling engine operation While expanding the increase in the pressure forces the piston up, powering the flywheel. The turning of the flywheel then moves the displacer down. Also, while contracting the pressure decreases, which in turn moves the piston down, imparting more energy to the flywheel. Here, the power piston should ideally be 90 degrees out of phase with the displacer piston as shown in figure 2.

The greater the temperature difference between the hot and cold sources, the greater the thermal efficiency. The maximum theoretical efficiency is equivalent to that of the Carnot Cycle, but the efficiency of real engines is less than this value because of friction and other losses.

We worked several weeks to accomplish our project within our time and budget. Following strategic approaches are followed to achieve our goal. Figure 3. Flowchart of project methodology 2. It is transmitted in the form electromagnetic radiation and does not requires medium to propagate.

It usually varies by geographic location, time of day, season, local landscape, local whether of a place. We have been brainstorming on how to increase the horse power. This is a very interesting project. I have a suggestion for improving performance. Even if the fins were very small they would still greatly increase the amount of surface area in contact with the air and therefore the rate of heat transfer.

Simple fins could be manually machined without much difficulty. And if you have access to CNC equipment you could easily make much fancier and more effective ones even artistic looking fins. Whether they would help much on the hot side would depend I think on what kind of heat source it was designed to use.

I think one way to improve performance would be to include heat recuperator between the top and bottom of the cylinder.

This needs a high thermal gradiant and resistance to work. I think this could be implemented by wrapping fine copper wire around the edge of the displacer piston. Copper is a very good conductor. Wrapping the wire as a coil around the edge would provide high thermal resistance between the top and bottom edges of the piston.

I would wind the copper wire over a thin layer of glue and alongside a fine fishing line to achieve separation and even spacing. I would then unwind the fishing line. As the air flowed around the edges of the displacer piston, the air would transfer heat to and from the copper. The use of fine wire would minimise added weight. This addition should improve power and efficiency. Post by Hutch » Fri Jan 27, pm. Post by Aviator » Fri Jan 27, pm.

Post by Alfista » Fri Jan 27, pm. Post by Alfista » Tue Jan 31, pm. Post by Aviator » Wed Feb 01, am. Post by Alfista » Wed Feb 01, pm. Post by Aviator » Wed Feb 01, pm. Search Advanced search. Quick links. I am using Evacuated Tube Collectors to heat vegetable oil to Centigrade in a closed system.

I have not decided on my coolant yet, but it will either be water being pumped in copper pipes in a closed system through the bottom of my pond, or perhaps another liquid that has a very low boiling point, such as Alcohol or Acetone without pumping, but instead put inside a large, hollow heat sink. I have not decided between a beta or gamma type engine yet. I am getting a professor from my alma mater to help me with some of the more complex calculations.

Currently I have three current engine designs in mind as possibilities. The First, which seems the most practical is the Sunpulse Electric: The village at Tamera has a larger, 1. This design looks very efficient, but it also looks overly complicated and I have been unable to find the internal design of it anywhere other than a few poor diagrams. So, my question to all of you is which do you think I should build, and why?