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Quick Guide for Sizing Off-Grid Solar Power System

Quick Guide for Sizing Off-Grid Solar Power System

Dr. Hedaya Mahmood Alasooly

halassouli@outlook.com

While every precaution has been taken in the preparation of this book, the publisher assumes no responsibility for errors or omissions, or for damages resulting from the use of the information contained herein.

Written by Dr. Hedaya Mahmood Alasooly

1. Introduction:

1. Introduction:

Solar power converts energy from the sun into electricity through the use of solar panels. A solar panel is a photovoltaic (PV) module that converts sunlight into direct current (DC) energy. This energy then flows into an inverter, converting it into alternating current (AC) energy that can be used to power homes, businesses, and even entire cities.

The three main types of solar power systems are: On-grid - also known as a grid-tie solar system. Off-grid - also known as a stand-alone power system. Hybrid - Solar system with battery storage with grid-connection.

This guide will provide different examples to calculate the size of Solar Panel, Battery and Inverter of Off-Grid Solar Power System. The report consists from the following parts:

Types of solar power system:
Example 1: Simple calculations for Off-Grid solar power system
Example 2: Simple calculation about solar panel
Example 3: Calculations of solar power system for Off Grid system
Example 4: Design of Off Grid solar system
Example 5: How to size Off-Grid PV system batteries
Example 6: How to size a Grid-Tie solar system
Example 7: Guide to designing Off-Grid and hybrid solar systems
Example 8: How to size your Off-Grid solar power system
Example of solar multi-function inverter/charger
References

2. Types of solar power system:

2. Types of solar power system:

a) Types of solar power system:

1. There are three types of solar power systems: On Grid, Off Grid and Hybrid Solar system.

2. Solar panels converts solar energy or sunlight to or DC power using what is known as photovoltaic effect.

3. The dc power can be stored on battery or converted by solar inverter into ac power which can be then used to run home appliances. Depending on the type of system, solar energy can either be fed into electricity grid for credits or stored into variety of different battery storage systems.

4. Let’s first describe the common components used by all three types before going into more details about the off-grid system and how it works and how to size it

b) On-grid solar system:

1. The following is the general diagram showing on-grid system components. This type of solar system is the most common one. It is connected to the home to the traditional electricity utility grid. This type of solar power system does not include any storage battery.

2. The solar power generated by the solar panels is continuously consumed by the appliances. In case the solar power system generating more power than the home is consuming, the access power can be sold back to the utility company under the scheme known as net metering.

3. When the solar system is not producing sufficient power, the balance power required by the appliances is drawn by the utility grid . This type of solar system requires few panels, wiring, boxes, disconnectors and inverter. The advantage of on-grid system is that they are much cheaper since they are less equipment than other types of solar power. This means lower initial cost. Also the operating cost of on-grid system is very low since solar panels have 20 to 25 years life span. Moreover the absence of batteries means lower maintenance works.

4. The setback of this type of solar power system is that when the sun goes down, you are able to use any of the energy that the solar panels produced.

c) Off-grid solar system:

1. Off-grid solar power system as the name suggests is completely independent solar power system with energy storage not connected to the main utility grid

2. The solar panels are the only source of energy in an off-grid solar power system. Off grid solar power system are ideal for remote rural areas or applications where other power sources are either un available or impractical

3. Off grid solar power system can be either ac-based systems in which case it includes inverter that convers the energy stored in batteries to ac power and feeds it to the ac appliances, or dc-based systems that are cheaper as they don’t need inverter but the power can only fed to dc appliances. This type of system is more expansive because it is bigger since its connected to electric grid. Thus requires more solar panels and batteries. One of the best things about this type of solar power system is that you don’t depend on the utility company. Another benefit when everyone else has the electricity your home will still have the power. This is very important to people with health conditions that require electronic devices or prefigurated medicines. More over because you are producing more electricity, you don’t have to pay bills to utility company. 4. On the other hand these systems come with some disadvantages. Higher initial cost. If you don’t have connection with utility company, you will need backup battery when there is no sun. Adding this source of backup battery will increase your costs. Also if the weather is cloudy or rainy for few days you may run out of stored electricity.

d) Hybrid solar power system:

1. Hybrid solar power system is a solar power system with energy that is similar to on-grid solar power system that comes with energy storage system in the form of battery backup

2. In the last couple of years this type of solar power system is becoming very popular even though it is very expansive . When solar energy production exceeds the demands, the excess solar power is utilized to charge batteries and stored for later use. When the production is lesser than the demand, the stored energy from the batteries is used to make short fall

3. The hybrid system consist from the PV arrays, the charge controller, a battery and inverter.

3.Example 1: Simple calculations for Off-Grid solar power system :

1. All these three types of solar power systems have their advantages and disadvantages. Customers can accordingly choose the type of solar power system that meets their electricity demands. After we covered the basics of the three system types , we will go in deep through the off-grid system. Let’s build solar power system to understand the role of each component.

2. Solar panels are definitely the first component. Simple explanation about solar panels working principles. Solar panels comprise of PV panels that comprise from many smaller units called photovoltaic cells. Photovoltaic cells simply convert sunlight to electricity. Solar cells contain material such as silicon that absorbs light energy. The energy knocks electrons loose so they can flow freely and produce a different in electrical potential or voltage. The flow of electrons or negative charges creates electric current. Solar cells have positive and negative contacts like in a battery. If the contacts are connected with conductive wire current flows from negative to positive contact. Since we are dealing with off-grid systems then the only source of energy is coming from sun so we need batteries to store this energy and be able to use it during night and cloudy days.

3. Connecting the panels directly to the batteries cause unlimited charging which they damage or explode the batteries. Off course we don’t want this to happen because the batteries are the most expansive components in this system. To avoid overcharging issues a charge controller should be installed between the panels and batteries. The role of charge controller is to protect by stopping the energy supply from PV panels to batteries when they are fully charged

4. As we previously said current produced by the PV panels is DC current. Charge controllers come also with DC outlet to supply loads that run with DC operating current.

5. Now we want to use the energy stored in batteries to power home loads like TV, lamps and so on.

6. But most home appliances operate on ac current and so we need

Impressum

Verlag: BookRix GmbH & Co. KG

Tag der Veröffentlichung: 08.11.2024
ISBN: 978-3-7554-8031-0

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