University of Maryland (UMD)

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.

The University of Maryland (UMD) and its partners will utilize UMD’s expertise in additive manufacturing (3D printing) and thermal engineering to develop novel, polymer-based, air-cooled heat exchangers for use in indirect dry-cooling systems. The innovation leverages UMD’s proprietary, cross media heat exchanger concept in which a low-cost, high-conductivity medium, such as aluminum, is encapsulated as a fiber in a polymeric material to facilitate more effective heat dissipation. To realize the innovative heat exchanger design, the team will develop an advanced, multi-head, composite 3D printer. The heat exchanger modules will be arranged in uniform rows with large spacing between the rows, which optimizes heat transfer while allowing for easier cleaning and maintenance. In addition to the system’s advanced cooling capacities, the heat exchangers will also be low-cost, low-weight, and resistant to corrosion. Ideally, UMD’s technology will be used in conjunction with a direct contact steam condenser in order to provide power plant cooling with performance comparable to evaporative, or wet-cooling, systems. UMD estimates that additive manufacturing could enable transformational heat exchanger designs with high performance at low cost, including the potential for onsite manufacturing of the heat exchanger, which could save additional transportation and installation costs.

If successful, UMD and its partners’ innovative heat exchanger design will lower the cost of air-cooled systems without reducing the efficiency of power plant cooling.