Chapter_4 Sustainable Energy Technologies (1)
Chapter Four: Solar System Components Sizing
Page 1: Introduction
Overview of Solar System components sizing for efficient energy generation and storage. The sizes of components significantly impact the overall performance and reliability of a solar power system.
Page 2: Sizing Steps Flowchart
Key Components:
Total Load (1): Essential for determining the energy needs of the system.
Inverter (2): Converts DC battery voltage into AC voltage for household use.
Array Configuration (3): Arrangement of solar panels to maximize exposure.
Batteries (4): Stores excess energy for usage during non-sunny periods.
Panels (5): Solar panels collect sunlight to generate electricity.
Charger (6): Regulates battery charging to prevent overcharging.
Page 3: Step 1 - Load Calculation
Importance:
Calculating the total energy required by the solar system is critical to ensure that the energy generated meets the needs of the house or facility. This includes assessing both immediate and projected future energy usage.
Lighting Calculation:
Total power required (W) = Number of bulbs × Power of each bulb (W)
Total energy required (Wh) = Total power required (W) × hours of use (h)
Page 4: Appliances Calculation
Fans:
Total power required (W) = Number of fans × Power of each fan (W)
Total energy required (Wh) = Total power required (W) × hours of use (h)
Fridges:
Total power required (W) = Number of fridges × Power of each fridge (W)
Total energy required (Wh) = Total power required (W) × hours of use (h)
Page 5: Additional Appliance Calculations
TVs:
Total power required (W) = Number of TVs × Power of each TV (W)
Total energy required (Wh) = Total power required (W) × hours of use (h)
Page 6: Aggregate Power Calculation
Total Power Requirement:
To get a comprehensive understanding of the energy needs, total power required should be calculated by adding the power requirements of all individual appliances:
Total power required (Wt) = Lighting (W) + Fans (W) + Fridges (W) + TVs (W) + Others (W)
Page 7: Total Energy Required Calculation
Aggregate Energy Required:
The total energy required is calculated to determine the energy contribution needed from the solar system:
Total Energy required (Et) = Lighting (Wh) + Fans (Wh) + Fridges (Wh) + TVs (Wh) + Others (Wh)
Page 8: Example Calculation
Load Calculation Example:
Lighting: Power: 3.75W, Quantity: 4, Total: 15W, Used: 8h, Energy: 120Wh
Hoover: Power: 600W, Quantity: 1, Used: 0.25h, Energy: 150Wh
Ceiling Fan: Power: 30W, Quantity: 2, Used: 7h, Energy: 420Wh
Total Power and Energy Calculation:
Total power: 2155W
Total energy required per day: 2625Wh
Page 9: Step 2 - Inverter Selection
Function of Inverter:
Converts DC battery voltage to AC voltage to supply power to the load, ensuring compatibility with household appliances. It is crucial that the inverter matches or exceeds the total load power to deal with power fluctuations.
Important Considerations:
Must handle peak power vs surge power of the load.
Page 10: Inverter Specifications
Characteristics:
Output voltage: Pure sinusoidal wave preferred for sensitive appliances.
Efficiency: Higher efficiency leads to better energy utilization.
Typical Issues: Inverters are often the most sophisticated component and can be prone to technical issues, requiring regular maintenance.
Page 11: Inverter Calculation Example
Total Load Power Required:
Total Load Power Required: 2155W
Safety Factor Application:
Safety Factor for sizing: 1.25 for all electrical devices to ensure reliability and mitigate risks of overload.
Efficiency Consideration:
Required Power = 2155W × 1.25 / 0.96 = 2835W
Recommended Inverter Size:
Recommended Inverter Size = 3000W, ensuring it accommodates peak loads during operation.
Page 12: Inverter Market Example
Specifications of a Market Example:
Rated output power: 3000W
Peak power: 4500VA
Output frequency: 50Hz
Page 13: Step 3 - Battery Selection
Purpose of Batteries:
Batteries are crucial for storing excess energy generated during sunny periods for use at night or during low sunlight conditions, ensuring a constant energy supply.
Important Terms:
Autonomy: Refers to the number of days the system can continuously supply power without solar recharging.
Page 14: Battery Characteristics
Key Aspects:
Efficiency: Loss rate during energy storage varies by type; lithium-ion batteries preferred due to higher efficiency and longevity.
Depth of Discharge (DoD): Percentage of total charge that the battery can discharge safely; lithium-ion batteries typically have 100% DoD, but it is advisable to leave 5% charge to enhance battery life.
Page 15: Battery Capacity Explained
Capacity (Ah):
Indicates how much current a battery can provide at a specific rate for a certain duration; is essential for planning the required battery bank size.
Page 16: Total System Efficiency
System Efficiency Calculation:
Total system efficiency is the multiplication of individual component efficiencies, calculated as: Total system efficiency = Charge Controller × Inverter × Connection × Panel × Battery DoD.
Example:
98% × 95% × 97% × 95% × 95% = 81.5% efficiency.
Page 17: Battery Bank Energy Calculation
Purpose:
Calculate the total energy required to determine the battery bank capacity needed for specified autonomy days.
Example Calculation:
Battery Bank Energy = Total energy required × Desired number of autonomy days / Overall Efficiency. For example: 2625 Wh × 2 days / 0.815 ≈ 6442 Wh.
Page 18: Capacity Based on Voltage
Battery Bank Capacity Calculation:
With given voltage levels (12V and 24V):
12V: 536.8Ah required
24V: 268.4Ah required
Page 19: Determining Number of Batteries
Calculation:
The number of batteries is determined based on individual battery capacity (e.g., 100Ah, 125Ah, etc.) using the total Ah required to ensure sufficient energy storage.
Page 20: No. of Batteries Required
Battery Count Calculated:
For 125Ah: 5 batteries needed
For 200Ah: 3 batteries needed
For 250Ah: 2 batteries needed
Page 21: Step 4 - Solar Array Selection
Energy Requirement:
6442Wh needed for solar array size calculation.
Considerations:
Sunshine hours (estimated 2.5 in winter) and other environmental factors.
Heat effects resulting in approximately 12% reduction in output.
Page 22: Solar Array Power Calculation
Solar Array Power Formula:
Total Solar Array Power = Total Energy Required / (hours of sunshine * Heat Effect).
Result Example:
2928.2W necessary for solar array generation.
Page 23: Panel Count Calculation
Standard Panel Sizes:
150W, 200W or 250W panels may be used; calculations show needing 12 panels based on power requirements.
Page 24: Panel Specifications
Example Panel Specs:
Maximum Power: 250W
General dimensions and weight information provided for sizing and structural concerns.
Page 25: Temperature Rise Calculation
Importance:
To assess Voc (open-circuit voltage) at cold temperatures for ensuring compatibility with the charge controller.
Page 26: Charge Controller Selection Criteria
Focus on Input Voltage:
Prevent potential damage from high voltage by selecting compatible charge controllers with specifications that exceed the expected operational range.
Page 27: Charge Controller Specifications
Voltage and Features:
Ensure that the Voc does not exceed controller specifications to maintain operational safety and efficiency.
Page 28: Series Connection of Panels
Determining Panel Connections:
Based on calculated Voc derived from cold weather conditions, series connections may drastically change voltage output and compatibility.
Page 29: Step 6 - Solar Array Configuration
Final Configuration Plan:
Two strings of 6 panels in series planned for optimal voltage output and total array specifications.
Page 30: Final Array Layout
Configuration Details:
Provide array voltage and current specifications to ensure operator clarity and operational guidance.
Page 31: Connecting Panels
Electrical Connections:
Can be series or parallel to balance voltage and amperage per design needs. Understanding application types is critical for system integrity.
Page 32: Series Connection Explanation
Effects:
Voltage increases while current remains the same; this is key for maximizing voltage output under certain conditions.
Page 33: Series Connection Variation
Further Considerations:
Variations in series connection with different ratings, particularly focusing on voltage calculations that need special attention.
Page 34: Parallel Connection Explained
Effects:
Voltage remains constant while current increases with the addition of more panels, useful for systems relying on consistent output power.
Page 35: Parallel Connection Variations
Same Description:
Detailing how parallel connections maintain voltage while increasing total available current based on battery and load considerations.
Page 36: I-V Curve Characteristics
Graphical Representation:
Provides insight into the power outputs in both series and parallel arrangements of panels; essential for understanding efficiency trends.
Page 37: PV Panel Specifications
Detailed Specifications:
Provided for a specific panel type including power ratings, temperature coefficients, and efficiency metrics crucial for sourcing decisions.
Page 38: Solar System Sizing Summary
Components Summary:
Comprehensive overview encapsulating load power and energy calculations along with ratings for Battery, Inverter, Solar Array, and Charge Controller to foster informed decision-making.
Page 39: Questions
Review:
Encouragement to prepare questions for review, ensuring solid understanding and readiness regarding sizing components and the overall solar system configuration.