Solar Power system sizing

 

The label in the picture is the power parameters of machine motor. I was task to size a solar power system that can run 10 of this machine simultaneously for 10 hours.

To size these system, Let's recap the given parameters and calculate the unknown.

From the label information provided on your clutch motor, here are the summarized points regarding its rated running power and other electrical characteristics:

1. Rated Running Power:

   - The motor is rated at 1/3 horsepower (HP). To convert this into watts (since 1 HP equals approximately 746 watts):

   Power (W) = 1/3 x 746= 249watts.

2. Rated Voltage and Current:

   - The motor operates at a voltage of 220 volts

   - The normal operating current is between 1.71 to 2.16 amperes.

3. Surge Multiplier Factor:

   - The label does not specify the inrush (surge) current explicitly, only the typical running and potential starting currents. The inrush current for motors can typically be several times higher than the running current, but without specific data, an accurate multiplier cannot be calculated. If the starting current is indeed at the higher value indicated (2.16 A), and assuming the lower end as the running current (1.71 A), you could consider this as a tentative range.

   - However, for precise analysis or calculations, specific motor startup characteristics or manufacturer data would be necessary.

Therefore from what we are given, we simply calculate the surge multiplier factor as

Surge factor = 2.16A/1.71A = 1.26 ≈ 1.3

4. Peak Power:

   - Peak power usually refers to the maximum power output of the motor, often occurring during start-up due to higher current draw. To calculate a theoretical peak power using the higher current value:

   - Peak Power (W)= Voltage (V) x Peak Current (A)

   Peak Power (W)= 220 x 2.16 = 475.2watts.

5. Revolutions Per Minute (RPM):

   - The motor operates at 2850 RPM, indicating a high-speed operation typical of a 2-pole motor design.

6. Electrical Frequency and Phase:

   - Designed for a 50 Hz frequency and single-phase electrical supply, typical in residential and many commercial settings outside of North America.

From the machine label

Input voltage= 220V

Peak power = 475.2W

Rated power(Running power) = 249W

Surge factor = 2.16A/1.71A = 1.26 ≈ 1.3

Take:

Solar hour = 5 hours 

Usage Time= 10 hours 

Number of machines = 10

 1.Total Peak Power Requirement:

   - Each machine has a peak power consumption of approximately 475.2 watts (calculated as 220V x 2.16A).

   - For 10 machines, the total peak power requirement is 475.2W x 10 = 4752W 

 2. Total Daily Energy Requirement:

   - To find the energy needed for 10 hours of operation daily, use the nominal power (not the peak) since machines typically don't operate at peak power constantly:

   - Nominal power per machine: 249 watts.

   - Total for 10 machines: 249 x 10 = 2490W

   - Daily energy requirement: 2490W x 10 Hours = 24900 W = 24.9 kWh.

 3. Solar Panel Sizing:

   - Assuming about 5 hours of effective sunlight per day:

   - Required panel capacity to generate 24.9 kWh per day: 24900W / 5hours = 4980W or 4.98 kW.

   - Due to system inefficiencies typically found in PV systems due to temperature loss, wiring, and conversion inefficiencies. Usually, this efficiency is about 85%, so the calculation would look something like this:

                            Required panel capacity=5 hours×0.8524.9 kWh​≈5.84 kW

4. Battery Storage (Optional):

   - If full autonomy is needed, sizing the battery to store enough power to run the machines for 10 hours:

   - Battery capacity needs to store at least 24.9 kWh. Considering efficiency losses (e.g., 85% battery efficiency), the required capacity would be higher: 24.9/0.85 = 29.3kWh

Taking into account the DOD (Depth of Discharge) in this context we are using Lithium-ion battery. So let's assume 80% DOD.

Required Battery Capacity=0.85×0.824.9 kWh​≈36.6 kWh

 5. Inverter Sizing:

   - The inverter should be sized to handle the total peak load, which is 4752 watts.

   - Choose an inverter that can manage at least this load plus a margin for safety and efficiency, typically 10-20% more: 4752 x 1.15 ≈ 5467W

6. Considerations for Installation

Recommendation For those in USA

• Number of Panels: 11 minimum (If we are using 565-watt Half-Cell Solar Panels)
  • This count is based on the required capacity of 5.84 kW, utilizing the higher wattage panels to achieve the necessary power output efficiently.
• Recommended Panel: Consider high-efficiency 565-watt panels from manufacturers like LG or Trina Solar. These panels are known for their high performance and durability, which will be beneficial in maximizing the energy capture from available sunlight.
• Inverter: A suitable inverter to manage this setup could be the SMA Sunny Tripower 6.0-US or SolarEdge SE5000H-US. These inverters are capable of efficiently handling the output from the solar panels and providing stable power delivery.
• Battery Storage: With a required capacity of approximately 36.6 kWh, considering 80% depth of discharge (DoD) and an efficiency rate of 85%, using three Tesla Powerwall units (each offering around 13.5 kWh) will comfortably meet and slightly exceed this storage requirement.
• Mounting System: A robust mounting system is recommended to support the high-wattage panels, possibly with adjustable tilt to maximize solar exposure throughout the year.
• System Monitoring and Management: Implementing a system that includes advanced monitoring capabilities will help in optimizing the performance of your solar setup. Inverters from SMA or SolarEdge come with integrated monitoring systems that allow for real-time tracking of energy production and usage.

RECOMMENDATION FOR AFRICA

  Tailoring a solar power system for use in Africa involves considering several key factors such as the high solar irradiance available in many parts of the continent, potential challenges in terms of infrastructure, local availability of components, and the need for systems that are robust and require minimal maintenance. Here’s how you might approach the design and component selection for such conditions:

 Recommendations for Solar Power System in Africa

1. Solar Panels

- Choice of Panels: Due to the high solar irradiance available in most parts of Africa, solar panels with high heat tolerance and efficiency are ideal. Consider using high-wattage panels like those from Canadian Solar, Jinko Solar, or Trina Solar, which offer durability and excellent performance under high temperatures.

- Panel Installation: Implement installations with a tilt that maximizes sun exposure year-round. Adjustable mounts can be advantageous during different seasons if practical.

2. Inverters

- Robust Inverters: Choose inverters that are known for their durability and ability to handle unstable grid conditions if grid-tied systems are considered. SMA and Victron Energy inverters are well-regarded for their robust performance and ability to function in off-grid settings as well.

- Hybrid Options: In regions with intermittent grid access, hybrid inverters that can manage solar, battery storage, and grid interaction seamlessly are recommended. Good choices include the SMA Flexible Storage System or products from Schneider Electric.

3. Battery Storage

- High Durability Batteries: Lithium-ion batteries are recommended due to their long lifespan, efficiency, and depth of discharge. Tesla Powerwall or LG Chem are excellent options; however, if cost or availability is an issue, consider lead-acid batteries that are more affordable and widely available, though they offer a shorter lifespan and lower efficiency.

- Sufficient Capacity: Ensure battery capacity is adequate to store solar energy during sunny hours for use at night, especially in areas with no grid access.

4. Mounting Systems

- Durable Mounting: Use mounting systems designed to withstand harsh weather conditions such as high winds and extreme temperatures. Stainless steel or anodized aluminium components are preferable for their resistance to corrosion.

5. System Monitoring and Management

- Remote Monitoring: Choose systems that offer remote monitoring capabilities to allow for easy management and troubleshooting without needing on-site visits, which can be crucial in remote areas.

6. Installation and Maintenance

- Professional Installation: Use qualified professionals for installation to ensure systems are correctly set up for optimal performance.

- Regular Maintenance: Plan for regular maintenance checks, especially in dusty environments where panel cleaning can significantly impact performance.

7. Local Considerations

- Local Availability and Support: Opt for equipment that has local support for easier maintenance and parts replacement.

- Cultural and Economic Factors: Consider scalable systems that can be expanded as needed, especially important in developing regions where initial investment might need to be minimal.

 General Recommendations

- Safety and Compliance: Follow international and local safety standards for installation and operation.

- Educational Outreach: Educate users on the operation and maintenance of systems to ensure longevity and effectiveness.

By incorporating these tailored recommendations, you can design a solar power system well-suited for African environments, balancing cost, efficiency, and durability, while considering the specific logistical and climatic challenges faced in the region.