Active Cooling Thermally Induced Vapor-Polymerization Effect (ACTIVE)

The conceptual ACTIVE skid is relatively small and simple in design.

Challenge

One of the major challenges for dry-cooling systems is the performance penalty imposed by air cooling when ambient temperatures are high. The performance penalty is the result of higher temperature cooling water returning to the condenser, raising condenser saturation pressure and lowering turbine output. The main objective of ACTIVE is to develop a disruptive dry cooling technology that enables high thermal-to-electric energy conversion efficiency during high ambient temperature excursions and with zero water loss.

The technical goal is to develop, design, fabricate, and demonstrate a 500 kWh ACTIVE prototype for power plant supplemental cooling and cold storage that meets the Advanced Research Projects Agency-Energy (ARPA-E) Advanced Research in Dry cooling (ARID) program performance and cost metrics.  

Solution

The ACTIVE system provides a solution to one of the principal challenges for power plant dry cooling. While there are other competing or emerging technologies that can provide thermal storage capacity, none can potentially meet ARID’s performance and cost targets. ACTIVE is an innovative approach that uses a depolymerization / polymerization cycle. It provides supplemental cooling and cold energy storage that can work as standalone system or synchronized with air-cooled units in order to cool below the ambient dry bulb temperature and preserve the power plant energy conversion efficiency. 

ARA’s SMART-Energy (SMART-E) group is conducting detailed analyses, including thermodynamic and kinetic analysis, DCU (depolymerization cooling unit) and PHU (polymerization heating unit) operational characteristics analysis, leading to DCU and PHU heat duty and design. The project focuses on developing an integrated supplemental cooling/cold energy storage system by first designing and then testing the DCU and PHU in benchtop scale. To mitigate the risks, SMART-E engineers employed computational fluid dynamics (CFD) modeling of chemical reactions combined with experimental data to design a compact and thermally efficient endothermic and exothermic chemical reactor / heat exchanger.  

By validating the design and obtaining design parameters for scaling up the units, the SMART-E group will then design, fabricate, and test a 50kW (500kWh) prototype. A focus from the start is the importance of turning this ARPA-E funded design concept into a commercially manufactured product. The SMART-E group will also place crucial emphasis on conducting a detailed cost analysis at each task level in order to ensure tech-to-market viability.

Impact

The interdependency between water and energy, commonly known as the water-energy nexus, has many facets, but perhaps none is so easily described as the use of water in the generation of electricity. The U.S. electric power industry has relied primarily on water cooling technologies to remove low-grade heat from thermoelectric power plants. These technologies include cooling towers and spray ponds, which dissipate a substantial amount of water into the atmosphere via evaporation. It is anticipated that within a 20-year time horizon, a combination of environmental concerns, increased water demand due to population growth, and the impacts of climate change will significantly constrain the available water supply that can be allocated to power plant cooling. It is also anticipated that smaller scale distributed electric power generation will continue to penetrate the market, including in regions where water cooling for low-grade heat removal is not feasible.

ARA is developing transformative new power plant cooling technology that will enable high thermal-to-electric energy conversion efficiency with zero net water dissipation to the atmosphere. With climate changes and fear of droughts around the world, ACTIVE will ensure the United States maintains a technological lead in developing and deploying advanced energy technologies and open new global markets for American products.

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