Method for optimal design of pipes for low-energy district heating, with focus on heat losses

被引:159
作者
Dalla Rosa, A. [1 ]
Li, H. [1 ]
Svendsen, S. [1 ]
机构
[1] Tech Univ Denmark, Dept Civil Engn, DK-2800 Lyngby, Denmark
关键词
District heating; Low energy; Heat loss; Steady-state simulation; Thermal conductivity; Finite-element method; SYSTEMS;
D O I
10.1016/j.energy.2011.01.024
中图分类号
O414.1 [热力学];
学科分类号
摘要
The synergy between highly energy-efficient buildings and low-energy district heating (DH) systems is a promising concept for the optimal integration of energy-saving policies and energy supply systems based on renewable energy (RE). Network transmission and distribution heat loss is one of the key factors in the optimal design of low-energy DH systems. Various pipe configurations are considered in this paper: flexible pre-insulated twin pipes with symmetrical or asymmetrical insulation, double pipes, and triple pipes. These technologies represent potential energy-efficient and cost-effective solutions for DH networks in low-heat density areas. We start with a review of theories and methods for steady-state heat loss calculation. Next, the article shows how detailed calculations with 2D-modeling of pipes can be carried out by means of computer software based on the finite element method (FEM). The model was validated by comparison with experimental measurements, analytical formulas, and data from the literature. We took into account the influence of the temperature-dependent conductivity coefficient of polyurethane insulation foam, which enabled us to achieve a high degree of accuracy. We also showed the influence of the soil temperature throughout the year. Finally, the article describes proposals for the optimal design of pipes for low-energy applications and presents methods for decreasing heat losses. (C) 2011 Elsevier Ltd. All rights reserved.
引用
收藏
页码:2407 / 2418
页数:12
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