Parameter Design of Coupled Thermoelectric Conversion Auxiliary Peak Shaving System for Condensing Unit

Abstract

[Introduction] In order to meet the demand for new energy power grid connection, the deep peak-shaving heat supply transformation of the original extraction and condensing cogeneration unit has become one of the important ways. Existing thermoelectric conversion devices, including thermoelectric pumps and electric boilers, provide a possible way to assist thermal power units in peak shaving. [Method] Taking a 350 MW extraction condensing unit as an example, an optimization model for peak shaving parameters assisted by a thermoelectric conversion device was established, and the influence of thermoelectric conversion equipment parameters on the deep peak shaving performance was analyzed. Secondly, the peak shaving depths of two typical thermoelectric conversion systems of electric heat pump and thermal storage electric boiler under different device capacities and different heat release rates were compared, respectively. Finally, the coal consumption rate and pollutant emission level of the 300 MW coal-fired unit were introduced, the energy-saving benefit of the system was pointed out, and the optimal parameters of the thermoelectric conversion device were given. [Result] The results show that when the thermal power of the electric heat pump is 100 MW and the heat release rate is also 100 MW, the peak shaving depth of the unit reaches the maximum value, which is about 73 MW. When the electric power of the regenerative electric boiler is 45 MW, and the heat release rate is 100 MW, the peak-shaving depth of the unit reaches the maximum value of 70.05 MW. The heat storage capacity of the regenerative electric boiler increases slightly within 24 h, and the net heat storage value is 967.5 kWh. [Conclusion] Power and heat release rate are important parameters to measure the peak shaving capacity of auxiliary units of thermoelectric conversion devices, and there must be a certain degree of matching between the two. Flexible matching of the type and parameters of the thermoelectric conversion device for different scenarios can greatly improve the peak shaving depth of the unit.

Keywords

• combined heat and power generation
• thermoelectric conversion device
• heat storage capacity
• exothermic rate
• the depth of the load