A feasibility and performance assessment of a low temperature district heating system - A North Japanese case study

摘要

This paper presents a high spatial resolution based method for design and operation of a low temperature district heating system and evaluates its feasibility and energy and exergy performance through case comparison. Selected case area is existing district in North Japan. The district heating system design and operation follows a bottom-up approach. The study scope takes into account the demand side, distribution and supply side where biomass CHP (combined heat and power) plant is selected as main supply source. Radiating floor heating system model is used to estimate building temperature requirement. Results indicate that low temperature heating is infeasible for non-residential buildings in North Japan at high loads. Improving building insulation decreases heating quality demand considerably. Low temperature district heating performs better than medium temperature, especially in terms of exergy efficiency, however requires a bit larger pipe diameter indicating cost trade-off between installation and operation cost. Implementing cascade configuration based on quality level of building energy demand results in highest system performance. Lower network temperature provides least net primary energy consumption primarily due to higher electricity generation of CHP plant. This transcends to favourable system exergy efficiency of low temperature operation due to high quality of electricity, increasing the exergy of the product. (C) 2015 Elsevier Ltd. All rights reserved.