Experimental cycle air cooling system for gas microturbine unit

Abstract

The article considers the Combustion Turbine Inlet Cooling (CTIC) system — an experimental system for cooling the cycle air entering the gas microturbine unit. This enables to save electrical power of the unit generated at the design level in the period of seasonal increase in air temperature. Cooling of the air at the inlet to the turbocharger of the unit occurs up to its design temperature (which is, according to the ISO standard, equal to 15˚С). The basis of the CTIC model is an industrial cooling system based on a vapor compression refrigeration unit with a cold accumulator. Water ice is used as a cold storage medium in the accumulator, while ice water is used as a medium cooling the cycle air (ice water is water at a temperature of 0.5˚С – 1˚С). The eff ect of cooling of cycle air is achieved by pumping ice water coming from the cold accumulator through an air-to-water heat exchanger installed at the inlet to the turbocharger. The purpose of the study was to determine the operating time of a cold accumulator, depending on the speed of the circulating water. The experiments were carried out on a model of a cooling system with a cold accumulator having a 200 kg ice storage and working with the Capstone C-30 microturbine. Maintaining the temperature of the cycle air at its design level is achieved using a frequency-controlled circulation pump and a digital measurement and control system with the LabVIEW software package. The results of the study show that the considered CTIC system, while discharging the cold accumulator, is able to maintain the required design temperature of the cycle air at 15°C for 6 hours, which is quite enough to cover the peak load of the working day. Technical and economic parameters of the plant are evaluated.