ABSTRACT

Current solar thermal systems used in Nepal are mostly for domestic hot water heating. Meanwhile, there is a growing need for space heating. A solar heating system can be configured to provide heat for both space heating and domestic hot water, leading to a solar combisystem. Research on residential solar combisystems in the Nepalean context barely exists in literature. This paper intends to propose, model and optimize a solar combisystem for typical single-family houses in Nepal. The optimization problem is formulated to have life-cycle cost as the objective function and a total of 11 variables, which are related to the sizing of combisystem components and the insulation thickness of building envelope. The number of hours not satisfying the thermostat heating set point is treated as the constraint. TRNSYS is used for modeling the solar combisystem. Particle Swarm optimization and the Hooke-Jeeves algorithm implemented in GenOpt are sequentially applied to solve the optimization problem. The results show that the optimization is effective to reduce the life-cycle cost by 66% for the Terai region and 77% for the Hilli region. The findings have demonstrated the importance of building envelope insulation to spread the use of solar combisystems in Nepal.

摘要

尼泊尔目前使用的太阳能热系统主要用于家庭热水加热。与此同时，对空间供暖的需求也在不断增长。太阳能加热系统可以配置为为空间加热和生活热水提供热量，从而形成太阳能组合系统。文献中几乎不存在关于尼泊尔背景下住宅太阳能组合系统的研究。本文旨在为尼泊尔典型的单户住宅提出、建模和优化太阳能组合系统。优化问题被制定为以生命周期成本为目标函数，共有 11 个变量，这些变量与组合系统组件的尺寸和建筑围护结构的绝缘厚度有关。不满足恒温器加热设定点的小时数被视为约束。TRNSYS 用于对太阳能组合系统进行建模。粒子群优化和在 GenOpt 中实现的 Hooke-Jeeves 算法依次应用于解决优化问题。结果表明，优化可有效降低 Terai 地区 66% 和 Hilli 地区 77% 的生命周期成本。研究结果证明了建筑围护结构绝缘对于在尼泊尔推广太阳能组合系统的重要性。