Global warming, rising Oil & Gas prices, demand for carbon fuels exceeding supply as the developing world industrialises, issues of Energy Security for the developed world.
The arguments for developing clean, renewable energy sources become more compelling by the day.
Solar Power offers the potential of unlimited clean energy. In the past the high cost of solar generated power has limited the scale of solar installations, but as carbon based fuel prices rise the economics for solar power becomes more attractive.
The OECD estimated that electricity supplied from solar power will increase by 60 fold in the next 25 years – before oil prices dramatically went above the $100 a barrel level in 2007.
Existing Solar Technologies
Thermal Concentrated Solar Power (CSP) is the most efficient, commercially proven solar technology. CSP applications use large parabolic mirrors focus the suns’ rays onto heat transfer tubes to produce heat which is then used to power a turbine electricity generator. Whilst highly efficient, CSP systems need to be very big to achieve economies of scale meaning the technology is only applicable for "utility scale" applications.
Photovoltaic Cell (PV) solar power units use flat panels of PV cells to convert sunlight directly to electricity. This technology is much more flexible and can be dimensioned to very small units. However the electricity produced is much more expensive than CSP produced power.
Microsharp approach to Solar Concentration
Microsharp Approach – Lower the cost solar concentration solutions
Microsharp is developing a range of solar concentrators utilising thin film lenses. These concentrators are much cheaper to manufacture and because they work at lower concentration ratios, require less precise, lower cost tracking devices. By this route we will make the benefits of concentration economically viable in much smaller unit sizes than was previously possible.
Our Technologies
Linear Fresnel Structures
A Linear, 1D Fresnel lens micro structure is applied to the underside of PMMA film.
The lens structure is engineered such that when the film is curved to a specific radius the lens concentrates the collimated sunlight into a line at a given focal point.
Point focussing Fresnel Lens Structures
2 dimensional Fresnel lenses cast from plastics are used in numerous Concentrated PV applications to focus sunlight on small areas of highly efficient PV materials, reducing the quantity of costly PV cells needed.
Thin film Fresnel lenses could be applied to this type of system, however large micro-structured lenses suffer significant efficiency losses towards their edges due to unwanted refractions.
To overcome this a "truncated cone" structure has been developed
Applications
CSP Thermal Electricity Generation
In a simple electricity generating system the thermal output is sent to an ORC Low temperature electricity generator.
ORC Generator works at circa 200c
Thermal storage can be so that the system can continue to provide power in periods of low sun or at night.
Alternatively system can be “grid connected” so that power generated simple augments grid electricity supply
CSP Thermal Air Conditioning
In hot climates around 70% of a buildings energy load is used providing air conditioning
Most solar power units first convert sun energy to electricity which is then used to power a conventional compressor driven air conditioning unit
The dual conversion process is inherently inefficient
With a Thermal CSP solar power plant, the thermal heat generated is used directly to power an Absorption Refrigeration unit
By using a more efficient CSP unit connected directly to an absorption refrigeration unit the total system efficiency can be increased by 50% as compared to a traditional PV / Compressor set up
CSP Thermal Trigeneration
Trigeneration is a comprehensive building energy supply system where a solar plant can provide the majority of a buildings energy needs highly efficiently by using the simplest energy conversion routes.
The thermal power produced is used to
Directly supply a buildings hot water needs
Provide Air conditioning via a thermal powered absorption refrigeration unit
Provide electricity via an ORC low temperature generator.
The implementation of such a system in a hotel designed to be inherently energy efficient provides the potential to design a totally “Carbon Neutral” building
Building Intergrated PV Concentrator
A linear Fresnel Concentration system can also be utilised to focus sunlight onto an array of PV cells.
This technology can be used to produce Concentrated PV panel units that can be integrated into building design in a similar way to standard, non concentrated PV panels
This design gives two advantages over traditional PV panels
The higher efficiency of concentration / Reduced PV cell cost
The lens concentrated system allows ambient light to pass through the unit providing natural light to the space below.
When used in conjunction with light filtering devices the system can actively manage the light and temperature conditions within a building, providing light shade / cooling in full sun conditions and more natural light and insulation in cooler periods
PV Concentrator System Utilising Truncated Cone Lens Structure
In this system a single truncated lens concentrates at circa 20 suns onto a high efficiency PV wafer.
100 such units are then mounted onto a tracked panel
System uses circa 1/20th of the Silicon wafer needed in an unconcentrated system, more than offsetting the cost of the concentration and tracking systems
