A 150Kw Integrated Solar Combined Cycle (ISCC) Power Plant

Abstract

With the soaring price of oil and the global push toward reduction in carbon emissions, renewable energy is treated by many as a solution to the economic and environmental cost of consumption of fossil fuels. With the power plant reviewed in this paper use of Solar and Bio-fuels will be attained. During the day power needs can be met with Solar energy and when that energy supply is not adequate can use bio-fuels or fuel of choice (gaseous or liquid). If there is a need for use only with Solar energy (i.e. peak power demand) can shut down and restart when desired. Due to the size of the unit, start up is not a long labor intensive task and can be accomplished within the hour. The 150 Kw Integrated Solar Combined Cycle (ISCC) power plant is for commercial and residential use. The unit will produce 150 Kw electrical power output to customer with Solar Thermal Energy (STE). Solar Thermal energy is attained from parabolic trough concentrator(s). Working fluid in the STE system is Syltherm 800 (Silicone Heat Transfer Fluid) is acceptable use from –40F to 750 F. This fluid is heated and passes through a heat exchanger to transfer energy to the closed rankine cycle (where the liquid is changed to vapor stage. Steady state analysis performed on the rankine cycle, with ammonia / water mixture (50/50) used NIST standard reference database 23 for the thermodynamic and transport properties REFPROP [1]. A unique feature with the combined cycle unit, is the rankine cycle turbine wheel is directly attached to the power producing gas turbine spool, thus share a common high speed permanent magnet alternator assembly. The core gas turbine engine used in the combined cycle is a two spool, high pressure ratio (11:1) simple cycle microturbine with cycle efficiency of 20%, at 70Kw output electrical power (sea level standard day). The latter is defined as model TMA 70SC. In addition to the gas turbine engine and rankine turbine stage, the combined cycle incorporates a gas turbine waste heat boiler, economizer, condenser and economizer fluid preheater. The combined cycle unit, without thermal energy, will produce 145Kw (sea level standard day) with an electrical output efficiency of 40%. The gas turbine exhaust to atmosphere will be less than 240 F. The ISCC unit power producing spool / rotor will operate at 100% N regardless of gas turbine power demand. Whereas, spool number one will vary with gas turbine power demand. When the available solar thermal energy decreases the gas turbine fuel flow will increase to maintain electrical power, pending day conditions. The ISCC power plant, can be used for main power plants in [stand alone] communities, business, industrial or distributed energy (D.E.). Also, will provide electrical power to the customer at lower rate than traditional power companies.