Những lưu ý khi lắp đặt hệ thống điện năng lượng mặt trời

1. Demand for electricity (kWh) and desired rate of savings?

To understand the economics of installing a solar power system, it is important that you determine how much electricity you consume in a year. Simply check the electricity bill for each month to determine the average usage demand. Usually, sunny months will yield more than rainy months. A suitable PV system has a high ratio of power generation to cut power consumption.

Tip: Before the Ministry of Finance approves the power purchase agreement scheduled for the end of 2018, it is advisable to prioritize investment in solar power if you need to use a lot during the day. As for customers who have demand but use a lot at night, they should consider investing with a permissible budget, and investing with PV output about 70% of the electricity demand.

Balance load demand and output from PV for economic efficiency.

An efficient solar cell system will balance the amount of electricity generated by PV and the load consumed.

2. Determine the available area space

To determine how many solar panels you can use, it is important to know that your roof space has enough space and capacity to build. Based on the size of your house, draw a plan of your roof on a piece of paper, determining the specific direction. If you want to be more technical, you can use the free Google SketchUp tool or the AutoCAD program. Or contact a professional consultant for accurate and reasonable calculations.

Tip: Normally 1kWp solar cell needs 7-8m2 of ground area including maintenance space, distance between rows. The panels will be installed to the South to optimize output ...

Analyze the distance and direction of shadow between panels and other objects.

3. Calculate how much energy the solar battery system can generate

You can refer to the NREL (US National Renewable Energy Laboratory) Website for solar radiation data statistics from which to calculate yield estimates. You can also use PV Watts's solar calculator or use specialized software like PVSYST (let your professional do the math) for a 12-month relative output forecast.

Tip: for the area of Ho Chi Minh City 1kWp solar cell system, if properly installed, will generate an average of 4-4.5 kWh / day. Balance the amount of electricity generated from the PV system and use up this amount of electricity is optimal.

The chart for calculating solar power output of each month of a system of 3.3kWp

4. Shade and yield issues

If there are obstacles like trees or buildings in the vicinity of your roof that could shade, you need to be careful. Shadows can reduce your system's output and can also damage solar cells. Shadows, even small places on the panel, will also affect performance not only that panel but also a series of serial batteries. You can use specialized software to analyze detailed gloss, layout distance of panels.

Tip: find out and ask the installer to clearly analyze the shading problem and the reduction to determine the system's efficiency.

Calculate the right angle and distance to get the best performance with specialized software.

Careful placement of shade even a small angle also reduces power output.

5. Choose the appropriate solar panels

There are hundreds of different solar panels on the market, determining which one (poly / mono / perc / Twin / double glass…) is the perfect fit for you can get complicated. Please note, solar panel selection should be in accordance with inverter output voltage and current rating. Other differences, such as coloration and financial limit, may also be a factor.

Tip: should consider choosing a reputable manufacturer in Tier 1, warranty period, panel performance, price. Most solar projects in Vietnam choose Poly, Perc, or Mono.

6. Select the inverter technology

Similar to choosing solar panels, choosing an inverter out of the many available is not easy. Consider suitable technology such as series inverter / central inverter / DC optimized inverter. To choose a suitable inverter, it is necessary to consider the purpose of the investment plan (need high performance?, Safety monitoring solution?, Good cost?, Origin brand?! ...).

Tip: consider the following: Quality & Reliability / Service & Support / Assurances / Features, Features / Monitoring System / Price.

Some brands of solar inverter can consider

7. Select the mounting mechanical bracket accessory system

Remember that 10% to 25% of the total cost will be the mechanical accessory frame system. Pay attention and take your time to decide which shelf system is best suited for your budget and for your roof. The system will last at least 20 years and it is one of the main components as it protects both the roof and the solar panels. A small mistake can damage the roof or injure people or property.

Aluminum frame type installed on tile roof

Aluminum frame type installed on the roof

8. PV power cable supplies, indispensable components

Some projects do not focus on choosing specialized DC power cables for solar power systems. This issue is very important, you should consider because PV DC cabling will be subjected to very high voltages eg 280 - 510V and currents up to 10A with high discharge potential. On the other hand, DC cable that will be installed outdoors for 25 years must be resistant to UV rays, heat, and oxidation for good electrical contact ...

Tip: Use dedicated DC cable 2 layers XLPE withstand 1000V / 1500V DC, meet IEC standards, TUV or UL certification. In addition, use T4, MC4 connector for connecting points, the connection boxes must use fireproof type, note not to connect unused cables with electrical tape, so use specialized high voltage terminals.

Notes on installation

The electrical specifications of the 3KW inverter that PV cable needs to meet.

9. Select contractor, construction consultant

Professional contractor will provide you with many optimal solutions to suit your needs. Accompanying a long-standing reputable contractor, there will be proper technical installation, safety, warranty and maintenance services that will help customers feel secure when investing in a high-value solar power system.

Note: solar panels are very durable and carry high loads. However, it should be noted that when moving installation, it should not exert strong force such as stepping on the middle of the panel, which may result in cracks in the cell that cannot be observed by the naked eye.

Tip: consider the above items to consult contractor information to choose the right solution. With solar power systems not only solar panels, inverters but a system that needs optimal balance (BOS) will be highly appreciated.

10. "Cloud" technology solar power monitoring system

Energy efficiency as a core component of Industry 4.0. Good monitoring system platform will monitor PV performance, report interactive power output graphs, visual charts. Instant failure diagnosis and early warning, remote configuration over the network. Integrate comprehensive reporting and analysis tools system with automatic reporting scheduling option. Easy decentralization and high security. The system operates throughout the life of the system.