Energy Benefit Analysis of Liquid Desiccant-Assisted Dedicated Outdoor Air System with Organic Rankine Cycle as a Central Ventilation System in Apartment Buildings

Abstract

This thesis is to investigate the energy benefit of a liquid desiccant-assisted dedicated outdoor air system (LDADOAS) proposed in this research. The LDADOAS consists of a liquid desiccant system, indirect evaporative cooler and heating coil. An organic Rankine cycle (ORC) which is a type of combined heat and power system was considered as a regeneration heat source. The waste heat energy released from the ORC was used for regeneration of the weak liquid desiccant solution in the proposed system. The LDADOAS was considered as a centralized ventilation system of a high-rise apartment building. The power generation capacity of ORC was based on the public electricity demand of the model apartment building. Energy performance of the proposed system was compared with two different types of existing dedicated outdoor air systems by detailed energy simulation. The reference ventilation systems dehumidifies with an enthalpy wheel and desiccant wheel. The result showed that the proposed system saved annual primary energy consumption compared with reference dedicated outdoor air systems considered in this study (i.e., 30% of case 1, 50.4% of case 2) because most of regeneration heat required for the desiccant system was supplied by the waste heat from the ORC. The proposed system shows lowest energy consumption compared with reference systems and highest system COP value in the desiccant peak design-day.