In thermoelectric power generation, only about 40% of the energy in the fuel is converted into electricity. In other words, the power plant operates at about 40% efficiency. The remainder of the energy is converted to low-grade waste heat that must be removed to maintain the power plant’s efficiency. Most power plants use water from nearby rivers, lakes, or the ocean for cooling. The water may pass directly over tubes containing the plant’s heated condenser water, and then be returned, warmer, to the original source, or it may be evaporated to carry off the heat in water vapor. In areas with limited water or under drought conditions, dry-cooling systems use air to remove heat from the plant’s condenser water. However, present dry-cooling technology reduces the power plant’s efficiency and requires costly equipment. With water supplies becoming increasingly strained in many areas, economical dry-cooling approaches that do not reduce the efficiency of power plans are critically needed. Innovative methods to allow cooling below the daytime ambient air temperature and improve heat exchange between air and the plant’s recirculating condenser water will provide the keys to ensuring the continued efficiency of power generation while decreasing the burden on water supplies.
Project Innovation + Advantages:
Applied Research Associates (ARA) will design and fabricate a dry-cooling system that overcomes the inherent thermodynamic performance penalty of air-cooled systems, particularly under high ambient temperatures. ARA’s ACTIVE cooling technology uses a polymerization thermochemical cycle to provide supplemental cooling and cool storage that can work as a standalone system or be synchronized with air-cooled units to cool power plant condenser water. The cool storage will be completed in two stages. During the day, the cool storage is maintained near the ambient temperature, and then at night the remainder of cooling can be done using the low temperature nighttime air. The cool storage unit is then ready for plant condenser reuse the next day. This technology will provide power plant condensers with return water at the necessary temperature levels to maintain power production at their optimum thermal efficiency.
If successful, ARA’s ACTIVE technology will demonstrate a cost-effective means of using a thermochemical cycle to reject waste heat to the ambient air without consuming water.
Power plants could maintain energy efficiency by using ARA’s technology instead of water cooling when water use is restricted.
The team’s ACTIVE system can eliminate the need for local water resources for cooling and help conserve water for other uses.
By using a novel de-polymerization/re-polymerization cycle, the team’s ACTIVE technology has seven times the heat storage capacity of commonly used materials, helping to reduce the cost of its system.