The feasibility analysis for the concept of low temperature district heating network with cascade utilization of heat between networks

Recently, low temperature district heating networks (LTDH) have received attention in district heating and cooling market due to their benefits in terms of efficiency, greenhouse gas reduction, flexibility to use renewable energy sources and economic benefits. In this work, physical and techno-economical aspects of the new concept of cascade types with high temperature district heating (HTDH) return is utilized to supply heat at low temperature networks. The HTDH return water temperature is around 45oC and supply of LTDH can be set around 60oC. The return water temperature of HTDH return line at 45oC can be raised to 60oC with the help of heat pump. A detailed study of major components, network design, pressure drop, heat loss and power consumption was performed to formulate an annual, hourly, based energy simulation to assess the techno-economic feasibility of the systems for different types of customers (residential & commercial) The economics were also analysed in terms of internal rate of return (IRR) and the results show that IRR for residential buildings varies from 14 ~ 17%. In order for the successful realization of the proposed system in the market new sustainable systems encouragement in government level is desired to be provided in the form of renewable energy target/certificates or CO2 reduction incentives especially at the initial stage of the commercialization of the model.