The role and benefits of solar water heating in the energy demands of low-income dwellings in Brazil
The role and benefits of solar water heating in the energy demands of low-income dwellings in Brazil
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DOI：
10.1016/j.enconman.2010.06.021
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发表时间：
2010-12
影响因子：
10.4
通讯作者：
H. Naspolini;H. Militão;R. Rüther
中科院分区：
文献类型：
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作者：
H. Naspolini;H. Militão;R. Rüther
在巴西，广泛使用电动淋浴头为家庭消费提供热水，导致负荷曲线在傍晚达到峰值，给发电、输电和配电设施带来了相当大的负担。平均而言，超过73%的巴西家庭使用这些3-8kW的电阻淋浴喷头。在巴西南部一些气候较为温和的地区，大部分巴西人口都集中在那里，90%以上的住宅建筑都有电动淋浴。对于住宅消费者来说，虽然这些大功率加热设备是成本最低的投资选择，但它们会导致高运行能源成本。此外，由于它们的负荷率非常低（通常低于2%），这些大功率淋浴喷头中的每一个都导致电力部门在基础设施方面的高投资成本回报相当低。特别是在低收入住宅中，电淋浴喷头是目前为止最高的电力负荷，在每月能源账单中占相当大的一部分。另一方面，巴西是世界上阳光最充足的国家之一，太阳能热水技术已经证明了巨大的经济效益和短的投资回收期。然而，由于其相对较高的初始投资成本，家用太阳能热水器主要用于高收入家庭。在这项工作中，我们展示了低收入家庭典型家用太阳能热水系统的低成本版本的潜力，在这种系统中，通常安装在热水箱内的电阻被可变功率电淋浴头所取代。这种设计避免了使用电力作为整个锅炉体积的辅助加热，因为只有通过淋浴喷头的水可能被电阻加热。这种系统配置是一种市售的低成本太阳能热水器。一个案例研究提出了具有统计代表性的一组低收入住宅与太阳能热水系统在Florianópolis -巴西。我们的结果表明，所获得的经济是相当可观的，无论是在能源消耗（千瓦时）和高峰需求（千瓦）的减少。与太阳能热水技术的高收入典型用户相比，这些经济对低收入人口和有关公用事业都代表着相对较高的利益。我们的研究结果还表明，避免的电力成本（对配电公用事业公司的好处）可能比避免的能源成本（对最终用户的好处）更大。在能源受限的高峰时段，公用事业公司可能会从能够将这些能源出售给其他支付更高电价的消费者中受益。
In Brazil the widespread use of electrical showerheads for providing hot water for domestic consumption contributes to a load curve that peaks in the early evening, imposing a considerable burden to generation, transmission, and distribution utilities. On average, over 73% of Brazilian households use these 3–8kW electrical resistance showerheads. In some of the more temperate climate regions in the south of the country, where most of the Brazilian population is concentrated, electrical showers are present in over 90% of residential buildings. For the residential consumer, while these high-power heating devices are the least-cost investment alternative, they lead to high running energy costs. Furthermore, due to their very low load factor (typically below 2%), each of these high-power showerheads results in considerably low return on the high investment costs in terms of infrastructure for the electricity sector. Particularly in low-income dwellings, electrical showerheads represent by far the highest electrical loads, resulting in a considerable component in the monthly energy bill. On the other hand, Brazil is one of the sunniest countries in the world, and solar water heating technologies have demonstrated large financial benefits and short payback times. Due to their comparatively higher initial investment costs, however, domestic solar water heaters are used mostly in higher income residences. In this work we present the potential of a low-cost version of the typical domestic solar water heating system for low-income dwellings, where the electrical resistance, which is normally installed inside the hot water tank, is replaced by a variable power electrical showerhead. This design avoids the use of electrical power as auxiliary heating for the whole of the boiler volume, since only the water which passes through the showerhead might be heated by the electrical resistance. This system configuration is a commercially available low-cost solar water heater option. A case-study is presented for a statistically representative group of low-income dwellings with solar water heating systems in Florianópolis – Brazil. Our results show that the economies obtained are considerable, both in terms of energy consumption (kWh) and peak demand (kW) reduction. When compared with higher income typical users of solar water heating technologies, these economies represent a relatively higher benefit, both for the low-income population, as well as for the utilities involved. Our results also show that the avoided power costs, a benefit for the distribution utility company, might be more substantial than the avoided energy costs, a benefit for the end user. In the energy constrained on-peak hours period, the utility company might benefit from being able to sell this energy to other higher paying tariff consumers.