GateCycle Software is described as 'GateCycle plant performance monitoring software predicts design and off-design performance of combined cycle plants, fossil boiler plants, nuclear power plants, cogeneration systems, combined heat-and-power plants, advanced gas turbine cycles and many other energy systems'. There are six alternatives to GateCycle Software for Windows, Linux and Mac. The best alternative is Engineering Equation Solver. It's not free, so if you're looking for a free alternative, you could try engineeringsuite. Other great apps like GateCycle Software are Aspen Plus (Paid), EBSILONProfessional (Paid), TRNSYS (Paid) and Thermoflow (Paid).
Aspen Plus is a market-leading process modeling environment for conceptual design, optimization, and performance monitoring for the chemical, polymer, specialty chemical, metals and minerals, and coal power industries.
TRNSYS is a transient systems simulation program with a modular structure. It recognizes a system description language in which the user specifies the components that constitute the system and the manner in which they are connected.
Thermoflow suite is complete, integrated platform for conceptualising, designing, optimizing, and modeling power plant systems, with detailed physical component models, preliminary engineering, cost estimates and economic analysis.
Program that solves numerically algebraic systems of non-linear, and linear, equations. It also includes a database of thermodynamical properties for many substances and a symbolic mathematical program to perform mathematical operations.