📚 Case Study: Designing a Solar-Powered Street Light | 太阳能路灯设计案例分析
In engineering, case studies are an excellent way to understand how theoretical knowledge is applied to solve real-world problems. In this article, we will walk through a practical case study of designing a solar-powered street light, exploring each stage of the engineering design process. This hands-on approach will help you see how different areas of engineering—such as structures, electronics, materials, and sustainability—come together in a single project.
在工程学中，案例分析是将理论知识应用于解决实际问题的绝佳方式。本文将带你完成一个太阳能路灯的设计实战案例，逐一探讨工程设计过程的各个阶段。这种实践方法将帮助你理解结构、电子、材料与可持续性等不同工程领域如何在一个项目中协同运作。
1. Introduction to the Case Study | 案例介绍
Our goal is to design a standalone solar-powered street light for a remote pathway that has no access to the electrical grid. The light must be reliable, cost-effective, and environmentally friendly. We will act as a team of engineers to define the problem, research possible solutions, develop a design, build a prototype, test it, and suggest improvements.
我们的目标是为一条未接入电网的偏远小径设计一款独立的太阳能路灯。该路灯必须可靠、经济且环保。我们将模拟工程师团队，定义问题、研究可行方案、进行设计、制作原型、测试并提出改进建议。
2. Identifying the Need | 识别需求
Before starting any design, we must identify why the product is needed. The pathway is currently dark at night, posing a safety hazard to pedestrians and cyclists. There is no nearby power line, making traditional grid-powered lighting impossible. A solar-powered solution can provide lighting without extensive wiring, using renewable energy. The key requirements are sufficient brightness, automatic on/off operation based on daylight, battery storage for overnight use, and weather-resistant construction.
在任何设计开始前，我们必须明确产品需求。这条小径夜间黑暗，对行人和骑车者造成安全隐患。附近没有电力线，传统的电网供电照明不可行。太阳能解决方案可利用可再生能源提供照明，无需大量布线。关键要求包括足够的亮度、根据日光自动开关、夜间使用的电池储能以及耐候结构。
3. Research and Background | 研究背景
We research existing solar street lights, photovoltaic (PV) panels, LED lighting technology, and battery types. We find that monocrystalline solar panels offer high efficiency, LEDs are energy-efficient and long-lasting, and lithium-ion batteries provide good energy density and lifespan. We also study the local climate: average daily sunlight hours and temperature ranges, which affect solar panel output and battery performance.
我们研究了现有的太阳能路灯、光伏板、LED照明技术和电池类型。研究发现，单晶硅太阳能板效率高，LED节能且寿命长，锂离子电池能量密度高且使用寿命长。我们还研究了当地气候：日均日照时数和温度范围，这些会影响太阳能板的输出和电池性能。
4. Design Specifications | 设计规格
Based on the need and research, we create a design specification. This includes: light output of at least 800 lumens, automatic dusk-to-dawn operation, battery capacity to provide 10 hours of light per night, solar panel power rating of 20 W, operating temperature range -10°C to 50°C, pole height of 4 metres, and an IP65 weatherproof rating. These specifications give clear targets for our design.
根据需求和研究，我们制定了设计规格。包括：光输出至少800流明，夜间自动运行，电池容量支持每晚10小时照明，太阳能板额定功率20瓦，工作温度范围-10°C至50°C，灯杆高度4米，IP65防护等级。这些规格为设计提供了明确的目标。
5. Generating Design Ideas | 构思设计方案
Our team brainstorms several concepts. One idea is a lantern-style light fixed to a pole with a separate solar panel on top. Another is an integrated unit where the panel, battery, and light are all in one compact housing. We sketch each concept, considering ease of installation, cost, and aesthetics. We select the integrated design because it simplifies wiring and assembly, while still meeting the specifications.
我们团队构思了几种方案。一种是固定在灯杆上的灯笼式灯具，太阳能板置于顶部；另一种是将电池、灯和太阳能板集成在一个紧凑外壳中的一体化设计。我们绘制了每种方案的草图，考虑安装便利性、成本和美观性。最终选择了一体化设计，因为它简化了布线和组装，同时满足规格要求。
6. Selecting Materials | 材料选择
Material choice is critical for durability. The pole will be made from galvanised steel to resist corrosion. The light housing will be aluminium with a powder coating for weather protection. The transparent cover for the LED will be tempered glass, which is strong and allows maximum light transmission. The solar panel frame will be anodised aluminium, and all fasteners will be stainless steel. We consider cost, strength, and environmental impact.
材料选择对耐用性至关重要。灯杆采用镀锌钢，可防腐蚀。灯具外壳采用铝材并粉末喷涂，以抵御天气影响。LED的透明罩采用钢化玻璃，强度高且透光性好。太阳能板边框采用阳极氧化铝，所有紧固件用不锈钢。我们考虑了成本、强度和环境影响。
7. Structural Design | 结构设计
The structure must withstand wind loads and its own weight. We perform simple calculations to check the bending stress on the pole. The cross-section is a circular hollow section with an outer diameter of 60 mm and wall thickness 3 mm. Wind force is estimated using the formula F = 0.5 × ρ × v² × A, where ρ is air density (1.2 kg/m³), v is wind speed (30 m/s as a design maximum), and A is the projected area. The resulting bending moment is below the yield strength of steel, so the design is safe.
结构必须承受风荷载和自身重量。我们进行了简单计算，检查灯杆的弯曲应力。横截面为圆形空心管，外径60毫米，壁厚3毫米。风荷载估计使用公式 F = 0.5 × ρ × v² × A，其中ρ为空气密度（1.2 千克/立方米），v为风速（设计最大值30 米/秒），A为投影面积。得出的弯矩低于钢材屈服强度，因此设计安全。
8. Electrical Circuit Design | 电路设计
The circuit consists of a solar panel, charge controller, battery, LED driver, and LED array. The charge controller prevents overcharging and deep discharge of the battery. The LED driver provides a constant current. We calculate the required battery capacity: Power consumption of LED = 10 W, for 10 hours gives 100 Wh. With a 12 V system, the required battery capacity is 100 Wh ÷ 12 V = 8.33 Ah. We choose a 12 V, 10 Ah lithium-ion battery for a safety margin. The solar panel must recharge the battery during the day; with 5 peak sun hours, a 20 W panel can generate 100 Wh, which matches the daily usage.
电路由太阳能板、充电控制器、电池、LED驱动器和LED阵列组成。充电控制器防止电池过充和过放。LED驱动器提供恒定电流。我们计算所需电池容量：LED功耗10 W，工作10小时需100 Wh。使用12 V系统，所需电池容量为100 Wh ÷ 12 V = 8.33 Ah。我们选择12 V 10 Ah锂离子电池以留有余量。太阳能板需在白天为电池充电；按5个峰值日照时数，20 W太阳能板可产生100 Wh，与日常用量匹配。
9. Testing and Evaluation | 测试与评估
We built a prototype and conducted tests. The light intensity was measured at 1 metre distance, recording 850 lumens. The automatic sensor switched the light on at dusk and off at dawn correctly. The battery lasted 11 hours on a full charge, exceeding the target. We also tested water resistance by spraying water from different angles; no ingress was observed. However, we found that in winter with only 3 hours of sun, the battery did not fully charge. The test results compared to specifications are shown in the table below.
| Specification | Target | Result |
|---|---|---|
| Light Output (lumens) | ≥800 | 850 |
| Night Operation (hours) | 10 | 11 |
| Water Ingress Protection | IP65 | Pass |
我们制作了原型并进行测试。在1米距离测量光强度，记录为850流明。自动传感器在黄昏正确开灯，黎明关灯。电池满电持续11小时，超过目标。我们还通过不同角度喷水测试防水性能，未发现进水。但发现冬季日照仅3小时时，电池无法充满。测试结果与规格对比如下表所示。
10. Improvements and Conclusion | 改进与总结
Based on test results, we recommend using a larger solar panel (30 W) or a more efficient charge controller to capture more energy in low light. We could also add a motion sensor to dim the light when no one is present, saving energy. This case study demonstrates the iterative nature of engineering design: from identifying needs to testing and refining the solution. Through this hands-on exercise, you have seen how core principles of WJEC Engineering are applied in a real-world project.
根据测试结果，我们建议使用更大功率的太阳能板（30 W）或更高效的充电控制器，以便在弱光下捕获更多能量。还可以增加运动传感器，无人时调暗灯光以节省能源。本案例展示了工程设计的迭代性：从识别需求到测试与改进解决方案。通过这个实战练习，你了解了WJEC工程学的核心原理如何应用于实际项目。
Published by TutorHao | Engineering Revision Series | aleveler.com
更多咨询请联系16621398022（同微信）
屏轩国际教育cambridge primary/secondary checkpoint, cat4, ukiset,ukcat,igcse,alevel,PAT,STEP,MAT, ibdp,ap,ssat,sat,sat2课程辅导，国外大学本科硕士研究生博士课程论文辅导