The existing HVAC system on board Landing Platform Docks (LPD)s, has been designed to operate in mild tropical environmental conditions such as the Mediterranean. This means that when the ship operates in extreme hot climates such as the Arabian Gulf and the Red sea region, the HVAC system is over loaded and cannot maintain the required design conditions. This results in uncomfortable and difficult working conditions for the ship’s occupants, and causes problems with equipment overheating, and overloading of cooling plants. In order to assess options for improving the HVAC system, an environmental model that is capable of dynamically simulating the environment inside the ship is created. The model takes into account weather data based on ship location and time, ship structure and insulation, sun location and shading effects, internal heat gains from equipment and people, and the performance of the HVAC systems; which includes chillers, cooling coils, heaters, controllers, etc. The environmental model is used to assess options for improving the HVAC system to accommodate extreme tropical conditions. The model also forms an environmental baseline for the ship that can be used for assessing the impact of any change in the operational profile of the ship.