July 02, 2007

Waste Heat Driven Hydraulic Engine

Waste Heat Driven Hydraulic Engine
Deluge, Inc. has developed a thermal hydraulic engine that is now ready for commercialization. The company has successfully completed long term field testing of the technology, and has obtained patents on the design in nearly 40 industrialized countries world wide.

The Natural Energy Engine™, requires no combustion, operates virtually silently, and generates no emissions. It operates by utilizing low level heat energy ~80°C suitable for many applications, from solar, geothermal, or any other heat source, including waste heat from existing processes.

The main components of the engine system are quite simple – a piston/cylinder and a heat transfer system. The cylinder contains a piston and a working fluid, and depending on the application may have a module to reposition the piston after each stroke. The heat transfer system comprises heat exchangers, a system to circulate the heat transfer fluid (typically water), and a simple circulation controller.

The key difference between a traditional combustion engine and the NE Engine is that the NE Engine relies on the transfer of heat to, and its subsequent removal from, a working fluid within the cylinder. As the working fluid is heated it expands, providing the pressure to drive the piston, and is subsequently cooled to complete the cycle.

The Company projects that engine configurations can easily be priced at 60-85% of power systems that produce equivalent output.

The NE Engine creates mechanical energy in a three step process:
Step 1: Heated water is collected – for many applications 80°C is suitable.

Step 2: The hot water enters a heat exchanger where the heat is transferred to a working fluid. The working fluid, typically liquefied CO2, has a very high coefficient of expansion, meaning that it expands and contracts significantly, based on its temperature, while remaining in a liquid state. As the working fluid is heated, it expands, pushing a piston in the engine’s cylinder.

Step 3: Cooling water – generally in the range of 100° F lower than the input water, with varying differentials depending on the application – then enters the heat exchanger causing the working fluid to contract, readying the piston for another stroke.
The back and forth movement of the piston creates mechanical energy directly from heat energy. This motion can be harnessed to operate a motor or to perform other work. Even lower temperatures and different differentials can be utilized, all of which attest to the versatility of the engine. A formula has been developed that establishes the ratio between the volume of the heat exchanger and the volume required to displace the piston for various fluids. This formula establishes design parameters for different horsepower systems.

In typical applications, due to the natural pressure of liquid CO2, the cylinder is constructed such that the CO2 working fluid is on one side of the piston and a pneumatic spring charged with nitrogen (N2) is on the other. Heating the working fluid results in increased pressure on the working fluid side of the piston. The hydraulic pressure of the working fluid must be high enough to overcome the starting torque (static friction) of the piston. When the pressure exceeds this point, the piston moves outward, compressing the pneumatic spring. After a predetermined time period, cooling water is sent through the heat exchanger. As the temperature decreases, the volume of the working fluid shrinks. The backpressure of the pneumatic spring helps push the piston back to its starting position.
Multiple piston engines have been built and operated. In two piston applications, the two pistons can be configured so that they offset each other in a single cylinder. As one piston extends, the other retracts. Between the pistons are two working chambers that allow the engine to do work, such as compressing gas, pressurizing water, or pumping hydraulic fluid through a hydraulic motor to turn a shaft. In four piston applications, heat exchanger assemblies timed to run at staggered intervals are utilized on each of the four cylinders. Valves that direct either the heated water or the cooling water to flow through the heat exchanger are timed using the four pistons. The four cylinders work in sequence continuously applying power to turn a rotating shaft for varying applications.
Sources of Efficiency and Economy
The fundamental design of the engine provides the basis for its efficiency and economy. First, the engine has an inherent efficiency because so little energy is dissipated in heat loss and noise generation. In an internal combustion engine, for example, much of the BTU energy in the gasoline is sent out the tailpipe as waste heat, but the NE Engine can actually recycle whatever heat is not used. In part, this is because the engine operates at low temperatures – the NE Engine uses heat differentials of approximately 100° Fahrenheit to produce usable power.
Additionally, the NE Engine is more efficient because so little energy is used for indirect motions. An internal combustion engine uses a significant fraction of its power to overcome friction and operate ancillary functions, such as valves, cooling circulation, and the like. Additionally, each cylinder in an internal combustion engine typically provides power only on every second or fourth stroke, while each stroke of the NE Engine is a power stroke.
Another efficiency advantage of the engine is in power transfer. Unlike an internal combustion engine, for example, there are no camshafts with their friction and power losses, no gearing, and no transmission. Of course, in applications where linear power must be converted to rotary power, traditional methods or even hydraulic converters can be used. Although the engine’s high torque typically makes gearing and transmissions unnecessary, gearing is one option to generate even more rapid – or slower – movement than the engine’s normal cycle.
The result is a highly efficient, virtually silent, direct drive engine that can easily be configured to use no traditional fuels and generate no pollution whatsoever.
In sum, the real economic advantage of the NE Engine is its lower operating cost and increased efficiency over competing gasoline, diesel or electric powered engines. Unlike conventional engines that require costly fossil fuel or electricity, the NE Engine fuel is simply low grade heat – something that can be supplied by a variety of sources including solar thermal, geothermal, ocean thermal, waste heat or small amounts of electricity or carbon-based fuels. The engine’s ability to effectively utilize low grade heat results in minimal fuel costs.
The NE Engine is inherently simple with few moving parts; therefore, is easier to manufacture and to maintain than conventional engines. Deluge’s technology creates an affordable alternative to the more technologically complex products currently available.
Product Features and Benefits
Overall features and benefits of NE Engine technology include the following:

Proven Technology:
The engine is based on recognized, proven, understandable technology of modest complexity.
Flexible Design:
The engine is designed so that it can be fabricated using existing off-the-shelf components and machined parts from existing fabrication plants, enabling access to a diverse source of parts vendors around the world, resulting in competitive pricing.
Simple Maintenance:
Training is of a mechanical nature, and does not require expensive high tech testing equipment, allowing for a broad range of skilled individuals who can be made field ready in a relatively short period of time.
The engine has a robust design for long functional life, and easy repair and maintenance.
Independent Power:
Self-contained products can easily be configured that work well “off the grid” in remote locations.
Multiple Fuel Options:
Multiple fuel sources include solar thermal, geothermal, ocean thermal, natural gas, propane, waste heat and others, allowing for flexibility in choosing the most cost effective and available energy and backup energy source options.
Low capital cost:
The Company projects that engine configurations can easily be priced at some 60-85% of power systems that produce equivalent output.
Low operating costs:
Depending on configurations, operating costs can easily range from 25-75% of power systems that produce equivalent output, and can actually be as little as 4% (a 96% reduction in costs) – which can justify replacement due to the quick payback.
Pollution free:
The engines create no environmental waste, are inherently safe to operate, and produce no noise. They can be configured to be entirely “green” and pollution free.
Cost Efficiencies with Size:
As engines are built in larger sizes, a dramatic decrease in cost will occur when approaching the 200 horsepower range. As with many technologies, projections beyond that range will continue to reduce the cost per horsepower.
Above All.........Operating cost is claimed to be 4-15% of the conventional engines. What more you can expect from any R&D developemnt..........
Your reactions........?????

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Anonymous said...

how long would the CO2 charge last under normal operating conditions? I've used gas springs before, and even without forced thermal expansion and contraction from applied temperature cycling, they only last a couple years or a couple hundred cycles before they loose their charge.

profmaster said...

I dont have direct experience on this. However I doubt that any depletion in working fluid is allowable. You can consider sealed cylinders.

Ravinder said...

Dupont Hydro is a leading manufacturer and supplier ofhydraulic cylinders, hydraulic cylinder rods, tubes, jacks, power packs and repairs."/>

Ravinder said...

Dupont Hydro is a leading manufacturer and supplier of hydraulic cylinders, hydraulic cylinder rods, tubes, jacks, power packs and repairs.

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