TRNSYS is an extremely flexible, graphically based software environment used to simulate the behaviour of energy transient systems and energy building simulation (including LEED energy modelling). The vast majority of simulations are focused on assessing the performance of thermal and electrical energy systems. Simulate also the geothermal heat pump systems, coupled airflow modelling, energy system research, technology assessment, power plants, hydrogen fuel cell, wind and PV systems, system calibration. This book represent the TESS libraries including in TRNSYS and has more than 250 components. Each of the component libraries comes with a TRNSYS Model File (_.tmf) to use in the Simulation Studio interface, source code and an example TRNSYS Project (_.tpf) that demonstrates typical uses of the component models found in that library. TESS Libraries represent the best of in-house types at TESS (Thermal Energy System Specialists).