📗 Chapter 1 – PV Basics

🌤️ External Factors Influencing PV Systems

In this chapter, you’ll explore how external factors such as:

• Light color (yellow/white)
• Angle of incidence
• Light intensity
• Heat
• Pollution
• Shade

🌈 1.1 Light Color

In this section, you will find out how different light colors (wavelengths) affect the performance of a photovoltaic (PV) cell.

🔬 Experiment

Materials needed:

• Two lamps: LED and yellow light bulb
• PV modules (small or big)
• Multimeter
• Holder for PV panels

📝 Exercise

Task 1:
Which light source is less effective? Think about why and discuss with your neighbors.

Task 2:
Which curve is white light? Which one is yellow light? What fits to 1 and 2 in the graph?

Task 3:
Do the following statements refer to white or yellow light?

Statement 1:
This light contains all the colors. It has both high-energy and low-energy light.

– White Light

– Yellow Light

Statement 2:
This light, in the middle of the spectrum, has just the right energy and is absorbed efficiently by PV cells.

– White Light

– Yellow Light

📐 1.2 Angle of Incidence

This section explores how the angle (inclination) of a PV cell affects its power output.

🔬 Experiment

Materials needed:

• One lamp (yellow light bulb)
• PV modules (small or big)
• Multimeter
• Meter rule
• Holder for PV panels

📝 Exercise

Task 1:
Based on your observations, which position leads to the highest current and voltage? What is the corresponding angle of incidence?

Task 2:
What is the relationship between the angle of incidence and the current/voltage?

Task 3:
Derive the formula for inclination-induced losses based on the cosine law:

Task 4:
Assume the PV panel’s maximum power is P_max = 100kWh. The angle of incidence is 30°. Calculate the effective power output P_eff.

💡 1.3 Light Intensity

In this section, you will explore how the intensity of light affects the performance of a photovoltaic (PV) module.

🔬 Experiment

Materials needed:

• One lamp (yellow light bulb)
• PV modules (small or big)
• Multimeter
• Meter rule
• Holder for PV panels

📝 Exercise

Task 1:
What is the relationship between the distance of the lamp from the PV module and the generated current/voltage?

Task 2:
Discuss your answer with other groups and your teacher.

Task 3:
Fill in the blanks:

🔥 1.4 Impact of Heat on PV Module Performance

In this section, you will investigate how heating influences the performance of PV modules.

🔬 Experiment

Materials needed:

• One lamp (yellow light bulb)
• PV modules (small or big)
• Multimeter
• Meter rule
• Holder for PV panels

📝 Exercise

Task 1:
How does the performance of the PV module change when it is heated?
Discuss with your partner: What would be the best location in the world for installing PV systems?

Task 2:
What is the photoelectric effect? Fill in the missing terms in your worksheet using: Photon, Electron, Metal.

Task 3:
Match the following terms with their descriptions.

Task 4:
The statements below describe the PV power generation process. Number them in the correct order (1–5).

🧼 1.5 Impact of Pollution on PV Module Performance

In this section, you will explore how pollution affects the output of PV panels. Dirt, dust, or smog can block sunlight and reduce energy production.

🔬 Experiment

Materials needed:

• One lamp (yellow light bulb)
• PV modules (small or big)
• Multimeter
• Meter rule
• Holder for PV panels

📝 Exercise

Task 1:
How did the voltage and the current change? What effect did cleaning have on the panel’s performance?

Task 2:
What can be some strategies to keep PV panels functioning optimally?

🌑 1.6 Impact of Shadows on PV Module Performance

Shadows from trees, buildings, or clouds can significantly affect the power output of PV panels. This section explores just how impactful that can be.

🔬 Experiment

Materials needed:

• One lamp (yellow light bulb)
• PV modules (small or big)
• Multimeter
• Holder for PV panels

📝 Exercise

Task 1:
How did the voltage and the current change? What effect did shadows have on the performance?

Task 2:
What strategies could help avoid or reduce shading on PV panels?

📗 Chapter 2 – Connecting PV to a Load and MPP

In this chapter, you will learn about:

• PV panels in Series
• PV panels in Parallel
• Fixed load (Resistor)
• Changing load
• Local conditions and load changes

🔗 2.1 PV Panels in Series

In this section, you will understand the effect of connecting two PV cells in a series.

🔬 Experiment

Materials needed:

• One lamp (yellow light bulb)
• PV modules (small)
• Multimeter
• Various cables
• Holder for PV panels

📝 Exercise

Task 1:
Discuss with others in the room (maybe stand up and talk to different people in the class). What are the PROS and CONS of series connection?

🔗 2.2 PV Panels in Parallel

In this section, you will understand the effect of connecting two PV cells in parallel.

🔬 Experiment

Materials needed:

• One lamp (yellow light bulb)
• PV modules (small)
• Multimeter
• Various cables
• Holder for PV panels

📝 Exercise

When we say, “PVs are current sources”, we mean that PV systems primarily produce a steady flow of current, depending on the available sunlight. Unlike a battery with a fixed voltage, a PV system adjusts its output based on sunlight intensity.

Task 1:
What happens with the current on a sunny day?
What happens with the current on a cloudy day?

Task 2:
What are the PROS and CONS of parallel connection?

🧱 2.3 Fixed Load (Resistor)

In this section, you will understand how a resistor works when connected to a PV module.

🔬 Experiment

Materials needed:

• One lamp (yellow light bulb)
• PV modules (small or big)
• Multimeter
• Various cables
• Holder for PV panels
• Resistance (Potentiometer)

📝 Exercise

Task 1:
How did the voltage and current change when the resistor was connected?
Please draw a graph with the voltage (V) on the X-axis and the current (A) on the Y-axis.
Insert your measured values as points on the graph.
Example: Resistor P → (Voltage / Current)

🔄 2.4 Changing Load

This section explores how changing the resistance affects the PV system’s performance and the operating point on the V-I curve.

🔬 Experiment

Materials needed:

• One lamp (yellow light bulb)
• PV modules (small or big)
• Multimeter
• Various cables
• Holder for PV panels
• Resistance (Potentiometer)

Plot the new points P_new (U | I) in the graph you drew in the previous exercise!

📝 Exercise

Task 1:
Plot the different points you measured into a graph.
Connect the dots to form a curve. Can you find a Maximum?

🌍 2.5 Local Conditions and Load Changes

This section explores how different environmental conditions (e.g., light, temperature) influence the operating point of a PV system when the load is varied.

🔬 Experiment

Materials needed:

• One lamp (yellow light bulb)
• PV modules (small or big)
• Multimeter
• Various cables
• Holder for PV panels
• Resistance (Potentiometer)

📝 Exercise

Task 1:
Replot your curve from section 2.4 and add the new curve from this experiment.

Task 2:
What changed compared to before? What happened to the maximum? Please discuss with your seat neighbor.

📗 Chapter 3 – Connecting PV to a Load and MPP

🔋 3.1 MPPT – Maximum Power Point Tracking

❓ Nice to Know
Imagine you have a toy car with a PV cell on the roof that is powered only by sunlight.
You know that it gets its energy from the sun through small solar cells on its roof. For the car to go as fast as possible, it needs to get just the right amount of energy from the sun all the time. But the amount of sunlight hitting the solar cells changes all the time – sometimes it’s very sunny, sometimes it’s cloudy, and sometimes the sun is in a different position in the sky.


MPPT, or Maximum Power Point Tracking, is like a very smart friend who makes sure your solar car always gets the best possible amount of energy, no matter how the sun is shining.


This smart friend constantly watches and adjusts things to make sure the car always gets the maximum power it can use.

Repetition:
As we have learned before, there are changing Sunlight Conditions: The amount of sunlight hitting the solar cells keeps changing. When it’s sunny, the solar cells produce more energy, and when it’s cloudy, they produce less. The temperature also affects how well the solar cells work – they perform differently when it’s hot compared to when it’s cool.

🔬 Experiment

Connect the PV to the MPPT controller.

📝 Exercise

Task: What might be happening inside this MPPT controller? Please discuss this with your seat neighbor.

🛠️ 3.2 Controlling the MPPT

🔬 Experiment

Try to control the MPPT controller manually, as the load is changed.

📝 Exercise

• Task 1: What do you notice? How can the MPP direction be estimated? Discuss with your seat neighbor.
• Task 2: How can the MPP be tracked automatically? Switch the MPPT to automatic mode and observe.
• Task 3: What can you observe?
• Task 4: Switch the controller to pure PWM mode. Do you notice anything?

⚖️ 3.3 PWM vs. MPPT

📝 Exercise

Task: Which is better in your opinion: PWM or MPPT? Please consider both the benefits of each application and the costs.

🔍 Chapter 4 – Application: Analyzing Energy Consumption Profiles of Household Appliances

📘 In this exercise, you will learn about:

• Visualizing energy consumption profiles of household appliances
• Data analysis using Pivot Tables
• Analyzing different usage modes for specific appliances
• Calculating energy consumption and associated costs
• Evaluating photovoltaic (PV) system options for residential use

Materials you will need for this task:

• Excel file named “Exercise_Appliances”
• Computer with Excel software (Excel)

🔧 Task 1: Visualizing Energy Consumption Profiles of Household Appliances

📋 Initial Descriptions:

In this part you are given brief descriptions of the energy consumption profiles of four different household appliances. In the next section, you will be asked to create charts using Excel that visualize the actual energy consumption profiles of these devices. Then you will match the descriptions with the corresponding visuals. Here are the basic descriptions:

Washing Machine (WM):

• Multiple Peaks over the duration of operation
• High peaks during washing/heating cycles
• Relatively lower peaks for spinning cycles towards the end

Dishwasher (DW):

• Multiple Peaks over the duration of operation
• Peak level values of the spikes are generally close to each other

Kettle (K):

• Rapid and high spike in power usage
• Consistent power level during operation

Hair Dryer (HD):

• Rapid and high spike in power usage
• Depending on the operation mode it can have different peak values (The peak is lower than Kettle for the example)
• Consistent power level during operation

📊 Data Analysis and Visualization:

• Open the Excel file named Exercise_Appliances and navigate to the sheet named Task 1. Here you will find the combined datasets for the energy consumption profiles of 4 household appliances mentioned above.
• They are labeled as HA1 (HouseholdAppliance1), HA2, HA3, and HA4 in a random order.
• Your task is to perform a Pivot Table Analysis to generate charts for each appliance.
• After creating the PivotTable charts, discuss and match the labels with the correct appliance names. Fill your answers in the boxes below.

🧪 Task 2: Analyzing Different Usage Modes for the Kettle

📋 Initial Descriptions:

For Task 2 and Task 3, we will focus on a single appliance — the Kettle. Now navigate to the sheet named “Task 2” in the Excel file (Exercise_Appliances).

📊 Data Analysis and Visualization:

• Open the sheet named Task 2. You will find datasets for different usage modes of the Kettle.
• Six different usage modes are labeled ModeA to ModeF, representing amounts of water from 2 to 7 cups, in random order.
  Note: 1 cup = 250 ml of water.
• Create two Pivot Tables:
  • One for visualizing the energy consumption profiles of each mode
  • Another for calculating the total energy consumption of each mode

📈 Energy Consumption Profiles:

Please identify how many cups of water were used for each mode (from 2 to 7 cups).

⚡ Total Energy Consumption:

Please fill in the total energy (in kWh) consumed by each mode (rounded to three decimal places).

🏠 Task 3: Practical Examples – Kettle

For the following exercises we will use the same Kettle and its data.

👪 Assumption:

Three user groups in different households use the same kettle. Their usage habits differ as follows:

• Household 1: Adds exactly 2 cups of excess water per use (if possible).
• Household 2: Adds exactly 1 cup of excess water per use (if possible).
• Household 3: Adds exactly the desired amount of water (no excess).

📘 Scenario 1

Each household uses the kettle 10 times a day. Actual needed amounts per day:

• 2 times: 3 cups
• 5 times: 4 cups
• 3 times: 5 cups

🧮 Exercise 1.1: Monthly Energy Consumption

Calculate the monthly total energy consumption (in kWh) of each household:

💡 Exercise 1.2: Monthly Electric Bill

Using the electricity pricing info, calculate the electric bill for each household (in GHp):

• 0–30 kWh → 63.4792 GHp/kWh
• 31–300 kWh → 140.5722 GHp/kWh
• > 301 kWh → 185.7432 GHp/kWh

Assume base household consumption (excluding kettle) = 260 kWh/month

📘 Scenario 2

Daily kettle usage per household:

• Household 1: 9 times
• Household 2: 10 times
• Household 3: 12 times

Needed amounts:

• 5 times: 5 Cups
• Remaining times: 4 Cups

🧮 Exercise 2.1: Monthly Energy Consumption

Calculate the monthly energy consumption of each household:

💡 Exercise 2.2: Monthly Electric Bill

Calculate the electric bill (GHp) for each household:

💨 Task 4: Practical Examples – Hair Dryer

Your task is to use Pivot Table Analysis to generate charts for a hair dryer’s different operation modes and total energy consumption. This is the same hair dryer from Task 1.

📈 1. Energy Consumption Profiles

Use the chart below to assign labels to each mode. The hair dryer has:

• 3 different heat settings: High, Medium, Low
• 2 different fan speed settings: High, Low

This makes 6 possible configurations. All modes run for ~120 seconds, so duration isn’t a key factor in total energy use.

⚡ 2. Total Energy Consumption

Please enter the energy consumed (rounded to 3 decimal places) for each configuration:

👥 3. Daily Use Scenarios

Two households use the hair dryer 3 times daily with different usage habits:

Household 1:

• 4 min – High Heat, High Speed
• 2 min – High Heat, Low Speed
• 2 min – Medium Heat, Low Speed

Household 2:

• 2 min – Medium Heat, High Speed
• 6 min – Medium Heat, Low Speed

🔋 Task 5: Evaluating the PV System Options for Residential Use

📚 Background Information

1. PV System Capacity

A 10 kW PV system can provide up to 10 kW of power under optimal conditions (ideal sunlight, angle, temperature). If your devices need more power than the system can provide, this can lead to underperformance or shutdowns.

2. Energy Production Estimates

Assuming 4–6 hours of peak sunlight per day:

• 10 kW × 4 hours = 40 kWh/day (lower estimate)
• 10 kW × 6 hours = 60 kWh/day (higher estimate)

3. Managing Power Consumption

• Battery Storage: Stores excess energy for later use.
• Grid Connection: Covers demand when solar energy isn’t enough.

Demand Side Management Strategies:

• Stagger high-power appliance usage
• Use energy-efficient appliances
• Implement smart home tech for better control and distribution

1. Comparison of Two Households with/without Demand Side Management (DSM)

Create charts with the provided dataset (12:00–14:00) and compare:

Household with DSM

Household without DSM

Fill in the peak consumption values and discuss possible implications of these peaks.

2. PV System Options (Ideal Conditions)

• System A: 3 kW – $4,000
• System B: 5 kW – $6,000
• System C: 10 kW – $10,000

Assume the non-DSM household peaks at 9999 W and consumes ~400 kWh monthly.

Exchange rate: 1 USD = 15.36 GH₵ = 1536 GHp

2.1 Energy Production and Cost Savings

Accra average sunlight: 6h 30min daily (~2377 hours/year)

• Lower estimate: 4h 30min/day
• Higher estimate: 8h/day

Use these to calculate monthly energy production and cost savings using Ghana’s electricity prices from Task 3.

2.2 Investment Cost and Payback Period

Calculate how long it would take each system to pay for itself based on monthly savings.

Then recommend the best option for each household based on their usage profile.

3. PV System Options (Real-Life Conditions)

Assume 75% efficiency due to real-world factors. Recalculate energy production and cost savings as above.

3.1 Energy Production and Cost Savings

• Use 75% of ideal daily output
• Repeat monthly calculations

3.2 Investment Cost and Payback Period

Repeat payback calculations under realistic efficiency. Decide which system is most suitable for each household.