Two main concerns exist within industrial forced draft air-cooled condensers (ACCs) in relation to concentrated solar power (CSP) plant performance. The first being that of excessive auxiliary power consumption. The second being underperformance during adverse atmospheric conditions i.e. peak atmospheric temperature levels or extreme windy conditions.
Within MinWaterCSP, an attempt is made to provide a cost and water effective solution to address both these concerns through custom designed high efficiency axial flow fans as well as the design and demonstration of a so-called directly integrated deluge cooled condenser cell. The former would reduce auxiliary power consumption in existing plants or enable the designer to reduce plant size for newly built systems through implementation of such fans. The latter would provide the plant operator with the option of introducing additional wet-cooling during adverse conditions, to either protect or control turbine power output and securing sufficient electricity on demand. This can be achieved while the water consumption would not exceed 10% of the amount consumed in wet-cooling towers. In addition, both the wet- and dry-cooling components are contained within one cooling system, attempting to reduce cooling plant size and capital cost, improving maintainability and driving down operational costs.
Although numerous analytical, numerical and lab-scale experimental analyses have been conducted for these technologies in the past, many questions on full scale system effects remain unanswered. Full scale testing is therefore of fundamental value. With this in mind, the full scale test facility at Stellenbosch was purposely designed and is presently being constructed and commissioned.
After commencing with the foundations in August 2017, the full scale test facility is nearing completion with some final fitment and commissioning to be completed in September 2018. The facility allows for the full scale testing of 24 ft diameter fans (of which the CSP fan, designed within the MinWaterCSP project will be the first) as well as isothermal testing of the novel directly integrated deluge condenser cell system. It is the only test facility of its kind globally.
Considering the present trajectory at which water use, effluent management and emissions regulations are becoming stricter, a growing drive towards higher and cost effective plant efficiency technologies should transpire. In addition to opening up new business and research opportunities, it is MinWaterCSP’s goal to bridge the cavity between academics and industry, in the present case, through full scale demonstration and testing of the abovementioned cooling technologies. Hopefully through such initiatives, tomorrow’s CSP plants would not only produce more clean electricity, but also do so more efficiently.
Figure 1: Schematic depicting the integration of a deluge condenser (wet) cell together with an ACC cell (Copyright: ENEXIO Management GmbH).
Figure 2: Full scale test facility nearly completed. Visible is the fan casing at the bottom as well as the deluge test section (opening at the top) (Copyright: ENEXIO Management GmbH, Kelvion Thermal Solutions (Pty) Ltd, Stellenbosch University).
Figure 3: A view inside the facility plenum chamber displaying the fan bridge, supporting the fan drive, gearbox, variable speed drive (VSD) and main power panel. The 24 ft CSP fan is mounted inside the fan casing and hanging from the outlet gearbox shaft. Numerous measurements can be taken for an envelope of air flow rates through the fan, controlled through a set of louvres at the outlet of the facility (Copyright: ENEXIO Management GmbH, Kelvion Thermal Solutions (Pty) Ltd, Stellenbosch University).
Figure 4: A frontal and internal view of the deluge condenser test section. Visible are sprayers at the top, a “dummy” tube bundle in the middle (inducing similar air flow losses and water flow distributions compared to an actual bundle) and the water collection system at the bottom from where the water is circulated back to the sprayers. Air flow, forced through the section by the 24 ft fan at the bottom, is controlled with a set of louvres at the outlet of the facility (Copyright: ENEXIO Management GmbH, Kelvion Thermal Solutions (Pty) Ltd, Stellenbosch University).
Authors:
Francois Louw, Kelvion Thermal Solutions
Albert Zapke, ENEXIO Management
Johan van der Spuy, Stellenbosch University
About Kelvion Thermal Solutions (Pty) Ltd
Kelvion Thermal Solutions (Pty) Ltd is an industrial cooling system supplier located in Johannesburg, South Africa. It is part of the Kelvion group of companies and provides cooling solutions to the petro-chemical and power industry.
With their experience and pioneering spirit in engineering, manufacturing and service, ENEXIO delivers state of the art solutions for power plants, water and wastewater applications – always inspired by their profound sense of responsibility for the overall management of resources and a clean environment. They deliver excellence and achieve customer satisfaction everywhere in the world. ENEXIO’s global network of employees works with an unceasing commitment to high quality, ecology and cost effective products and services.
About Stellenbosch University:
Stellenbosch University is known for its expertise in the research and analysis of large cooling systems (both wet- and dry-cooled). It already has extensive laboratory facilities available and the new full scale test facility will help to expand these capabilities. The facility is currently still in the design phase (the facility is being designed by Enexio) and significant progress has been made in obtaining the necessary university and municipal permissions for the building of the facility.
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