Fluid Solar will bring renewable solar thermal energy and low impact living spaces to one third of the worlds population in thirty years.



Hot Water Turbine


Solar heated hot water is converted to very low pressure saturated steam in a boiler operating at an ultra-low pressure and low-temperature range - even down to less than atmospheric pressure or <100C - up to 15 Bar or 200C, and passed through a unique axial flow multistage turbine. The turbine is very like a modern jet engine, with multiple stages (5-10 stages), using a pressure drop at each stage, to extract mechanical power from steam produced from stored solar heated water.

Importantly, at each stage, the motive steam stays above the critical steam condensation zone that would permit droplet formation to quickly damage the turbine blades.  Unwanted steam condensation leads to rapid blade erosion by water droplets and must be avoided at all costs. The Fluid Solar turbine achieves this critical design requirement by limiting energy extraction at each stage to engineered, pre-determined limits. The construction of multiple stages in a cost-effective manner in a small scale turbine allows Fluid Solar turbines to compete commercially with much larger existing turbine power plants. The capacity of our industry partners to manufacture all the parts with high precision, required for multi-stage axial flow turbines and at a sufficiently low cost to complete with existing technologies, places Fluid Solar in a very select position, worldwide.

The nirvana of distributed, cheap, dispatchable solar powered grid electric power is finally within reach utilising the Fluid Solar turbine.

Large volumes of water can be heated year-round by the Fluid Solar patented concentrated solar thermal power (CSP) system that tracks the sun through the day and through the seasons, without requiring the use of moving parts (See Thermal Panel). Thermal energy collection is boosted year round with the patented Fluid Solar concentrating panels. Energy can be stored cheaply and on any scale in Fluid Solar hot water tanks (See Thermal Storage), for hours or days. Typical hot water energy storage costs are <10% of the cost of equivalent electrical batteries. If required, large volume storage tanks permit massive quantities of solar thermal energy to be stored cheaply, for later use.

The Fluid Solar low-pressure steam turbine converts some of this thermal energy into electricity than can meet base load electrical grid demands (See base load substitution).

This is the hybrid thermal and electrical generation technology that can replace nuclear or fossil fuel-fired electricity generation, at comparable or lower cost. Conventional photovoltaic (PV) cells cannot meet on-demand electricity grid requirements outside the hours of usable sunlight. Current battery technology remains too expensive to compete commercially with fossil fuel-fired electricity power generation. Disposal, toxicity and fire risk remain important barriers to widespread fossil fuel substitution with electrical battery technology.

The rooftop area on conventional single and multi-story buildings is simply not sufficient to collect enough energy with PV cells that typically operate within a range of 6-12% efficiency, to provide for the heating, cooling and air conditioning demands of that building over a 24-hour cycle through the seasons. Even if electric battery prices are substantially reduced, a rooftop PV-based energy collection system is simply too small, to meet the demands, even of an efficient building. If PV cells are remotely located, substantial additional costs of grid distribution can double the real cost of PV based power and transmission losses of up to 30% render remote PV energy collection and battery storage even less commercially attractive. Consumers are faced with the unpleasant choice of lower living standards or higher energy consumption costs.

In contrast, the Fluid Solar thermal collector efficiency of more than 50% means that a moderate fraction of the rooftop area is sufficient to collect and store all thermal energy demands for heating and cooling in a well-designed Fluid Solar building. Fluid Solar House is proof that the roof top area is sufficient to collect the water, heat and PV electrical demands to power a building year-round while meeting the prescribed comfort standards for the occupants.

These three issues; low PV efficiency, high battery costs and grid distribution inefficiencies; represent a major technological impasse; preventing large-scale phasing out of fossil and nuclear powered electrical power generation. Fluid Solar Thermal technology permits large-scale, cost-effective collection, and storage of solar thermal energy for later use, on demand or at night, permitting off grid or “thin grid” functionality for occupied buildings on any scale.
Distributed collection of energy using Fluid Solar Thermal technology, stored as hot water and used "on location" can greatly reduce demand for grid power by making buildings largely energy self-sufficient, or even net energy exporters to the grid. It is estimated that Fluid Solar House has the capacity to contribute up to 7,000,000 km of electric car travel by delivering surplus daytime energy to cars parked at the building, over a 20-year energy cycle.

The modular nature of the solar thermal collectors, hot tank storage and Fluid Solar turbine operation for "on demand" power generation would permit extensive solar thermal farms to be sited alongside and under the vast existing grid networks crossing a nation or a continent, utilising land currently reserved for the overhead high tension grid connectors. Linear "solar thermal farms" could add electrical power "on demand" to existing grid infrastructure, replacing fossil fuel power generation and maximising the return to the community of the massive investment in grid infrastructure to date. Rainwater collected as runoff from the same land as would be occupied by solar thermal arrays is sufficient to permit cost effective discharge of the low-temperature thermal waste water energy back to ambient by indirect "mini cooling tower" technology also developed by Fluid Solar. All these technologies are currently being installed as working large scale prototypes, at Fluid Solar House in Adelaide, South Australia.

Developed for generation of electrical energy from stored solar thermal batteries, the Fluid Solar turbine is suited for decentralised solar plants and waste heat recovery. Being operable at input temperatures below 100°C, the unit can effectively utilise excess process heat that would otherwise be wasted or increase the utility of non-concentrating solar thermal arrays.

Renewable fuel cycles based on the burning of waste organic materials or plantation timber represent a further major potential application of the Fluid Solar turbine. Burning of cultivated cellulose simply returns captured CO2 to the atmosphere, with no additional greenhouse burden. Wooden materials represent a valuable store of solar energy in some areas of the world. The unique low-pressure, low-temperature capability of the Fluid Solar turbine means that low-tech wood fired boiler technology would permit local generation of electrical power to remote communities, with a local power cycle not dependent on fossil fuel or long-distance transport networks. 

Operational method

The Fluid Solar patented super low-pressure multi-stage axial flow turbine developed by the design team at Intex Holdings, is designed to operate in a partial vacuum with input steam temperatures as low as 80C with an effective operating range between 100 and 200 degrees Celsius. The output from the turbine is condensed by a patent pending direct contact condenser system designed to operate with condenser pressure as low as -13.3psig (1.4 psia, or a saturated water temperature of around 45 degrees Celsius).

Design and manufacturing 

The turbine has been designed with 5- 10 stages depending factors such as steam pressure and available steam flow.

The individual rotors and stators are manufactured as single units to reduce the cost complexity of manufacture and assembly. The design of the housing ensures leak free operation in a partial vacuum and precision alignment of each stage. The turbine is unique, with a wider operation range including ultra-low pressure operation, that is simply not possible with single stage designs.

The turbine has specifically been built with low-cost materials in order to minimise manufacturing cost and complexity. The gearbox incorporates an oil pump integrated into output shaft for maximum reliability, rolling element bearings, optional water cooling systems with low friction seal assembly. The condenser design allows for operation at near vacuum pressures, with an integrated water lubricated bushing process for the turbine shaft.

The lightweight package has a space requirement of 1mW x 0.7mL x 2.6mH.

Detailed specifications are available on request.