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    Free Energy: Waiting for the Giant Pumpkin


    This is a product that really is going to make a big splash. It is an example of excellence in engineering and innovation. Based on an innovative Rankine cycle engine, the Cogen technology produces clean and cost effective heating and electricity from a low temperature solar thermal system.

    COGEN-CUTAWAY-HOT-AND-COLDIncorporated into Cogen’s home energy system, the product provides households with 1 kW of electricity and 8.8 kW of heating from free solar energy.  Founded in 2000, Cogen Micro systems is an Australian based developer of solar thermal heating and power generation products that help our customers meet their heating, hot water and electricity needs.

    How it works

    The solar energy system uses evacuated tube collectors to capture thermal energy from the sun. This heat powers an Organic Rankine Cycle (ORC) heat engine which drives an alternator to produce electricity. Hot water is generated as a by-product.  The ORC engine is a new design which has less moving parts and is cheaper and simpler to manufacture than conventional ORC engines These solar systems will generate 1 kW of electricity, as well as provide hot water and space heating for the household.  The systems are modular and can be readily expanded to 20kWe for larger power and hot water requirements. The technology is well placed to service a niche within the mCHP market which will require a broad portfolio of technology and product mix to meet the needs of various customer segments. By integrating heating, hot water and electricity, the Cogen home energy system is cost competitive with network provided energy and provides a much lower carbon footprint. .

    What is Cogeneration?

    Most electricity is generated by large central power stations using big steam turbines which spin alternators that produce the alternating current (AC) electricity. The steam is produced in a large boiler fired by coal, oil, natural gas or a nuclear reaction. Only 30-40% of the thermal energy is converted to electricity. The rest is lost as heat. This is typically lost to the atmosphere using a cooling tower, or warms up the local river, lake or sea water from which the cooling water is drawn. About 8% of the electricity produced is lost in transporting over the grid. With the exception of nuclear power, the amount of greenhouse gases produced to produce all this heat which is wasted is enormous.

    What if every house was equipped with its own small power station? Then the heat produced as a by-product of the generation of electricity would heat your home rather than being wasted to the enviroment.  You would not need to burn or use additional fuel to keep your house warm.  Energy savings of 35%  is quite achievable, as the picture above shows. So are the reductions in greenhouse gas emissions – in fact a household can save several tonnes of CO2 in a year. This process is called co-generation. The name refers to the combined generation of two useful things at simultaneously, heat and electricity. It is sometimes also called Combined Heat and Power (CHP). This process has been used in industry for decades, where heat is required for factory processes and the electricity powers the machines. Household size systems (less than 10kW electrical, and more typically 1-3kW electrical) are called micro cogeneration or micro CHP systems.

    The Engine

    The core of the technology is a unique organic Rankine cycle (ORC) heat engine.  The engine is a reciprocating type, optimised for small (<20kW) applications.  It is highly innovative and is protected by several patents.  The innovations provide:

    • mechanical simplicity for low cost and durability,
    • 65% of Carnot efficiency
    • electronic control for optimum efficiency at all operating states,
    • Virtually vibration free and silent.


    The electronic control of vital engine parameters allows the operating parameters of the engine to be reconfigured on the fly, providing optimum efficiency under varying heat and load conditions.  The technology has been proven in extensive testing and is now being developed for production.  The first product to be released is the solar electricity, heating and hot water system.  Other micro CHP and waste heat recovery products will follow.

    24 Hour Solar

    What is not discussed on the companies website is the ability to store hot water to be be used after hours for electrical generation. With efficient well insulated storage tanks you can capture and store solar energy on demand. By adding additional panels and expanding the storage there is no need for battery storage. Fro remote power applications this may be a very cost effective way rather than burning diesel in gen sets.

    Source: http://www.cogenmicro.com/index.php?select=24

    Electric School Buses, Wind Power and Rural Communities
    Free Energy: Waiting for the Giant Pumpkin