Improvement of ship energy system has been required for better fuel oil economy and environmental sustainability. The authors proposed a concept of heat recovery system from exhaust gas, connected to diesel engine. Core device of the system is circulating fluidized bed (CFB) heat exchanger which has function of desulfurization. In this report, adjustment of the system was evaluated, speculating factors to familiarize the system: initial building cost, demand quantity of heat or electrical energy, and cooperation of auxiliary devices like air conditioner or SCR, and so on. And the authors proposed group of "One-through Type" system and "Circulation Type" system. The "One-through Type" system is to cooperate auxiliary heat devices, whose heat source is steam once used for electric generation. The "Circulation Type" system is built to focus on electric generation, to add condenser.In analysis of the "One-through Type" connected to 1400kW 4-stroke marine engine, maximum electrical output of "One-through Type A" system, consisting of the CFB and one of steam-turbine generator, was 2.81%of main engine power in 75% load. And "One-through Type B" system, consisting of the CFB, superheater and two of the generators, was up to 8.23%.