Direct Contact Flue Gas Economizer

Schendt Engineering Corp. was the prime consultant for this project with Structural, and Electrical sub-consultants to provided full design services. The first phase of the project involved performing a feasibility study to determine the initial cost along with the annual savings to determine the simple payback. The key to the success of the project was the renovation and addition to the El Pomar Sports Center which was designed for low temperature hot water heating to utilize the heat recovered by the economizer. This facility also has an indoor poor that is heater year around thereby allowing heat the recovered heat to be utilized year around. The heat recovery economizer system consisted of the direct contact flue gas economizer, induced draft fan, plate and frame heat exchanger, grey water pump and low temperature hot water pump. The induced draft fan and pumps were provided with variable frequency drives. Each generator required two motorized high temperature dampers, one for the stack and one for the interconnection breaching to the economizer. The economizer, heat exchanger, piping, valves and accessories in contact with the grey water were constructed of type 316 stainless steel. The low temperature hot water piping and components were constructed of standard carbon steel components. Distribution piping included installation of low temperature hot water and chilled water from the central plant to El Pomar. The low temperature hot water piping consisted of a direct bury cased piping system and the chilled water piping consisted of direct bury HDPE piping system. The project also involved installation of a new plate and frame heat exchanger to heat the pool, domestic hot water heat exchangers/storage tanks to preheat domestic hot water and secondary low temperature hot water pumps in El Pomar. The economizer controls consisted of a microprocessor based PLC with touchscreen interface. This system was integrated to the campus building automation system. The controls for the equipment in El Pomar were connected to the building automation system in El Pomar. The construction cost for this project was $800,000.