Utilizing solar energy is an effective method to decrease fossil energy consumption in marine field. Horizontally installed deck photovoltaic (PV) systems have been widely investigated to reduce navigation energy consumption on ocean-going ships. However, energy saving rate is unsatisfactory because of the low energy density of solar energy and the shadow caused by ship body. As for large amount of offshore small ships, it's even harder to utilize the existing technology since deck space is limited. In this paper, semi-transparent CdTe PV window system is proposed for offshore passenger ships without enough deck spaces but with large window area around ship cabin. Multidimensional PV windows can increase PV area and reduce heat gain inside the cabin, shadow effect caused by ship body is also avoided. Energy saving can be both achieved by electrical generation actively and cooling load reduction passively. Dynamic mathematical models of multidimensional PV window under moored and sailing conditions are established. Simulation results indicate that the daily electrical generation and average electrical efficiency are 0.74 kWh & 14.65% in moored condition and 0.83 kWh & 16.24% in sailing condition. Navigation leads to higher received solar radiation (18.2%), higher electrical generation (12.1%) and higher electrical efficiency (10.85%). Electricity created by PV window can support 6 h' continuous operation for auxiliary system on board. With PV windows, the average air temperature in cabin is decreased by 6.5 °C compared with ordinary windows. The average heat fluxes through four directions of PV windows are decreased by 75.44%, 73.64%, 47.52% and 75.33% compared with ordinary windows.