Are you considering solar hot water for your home but aren’t sure where to start? You’re in luck! A solar hot water system is one of the most effective ways to reduce your energy bills. Solar hot water systems are becoming increasingly popular in Australia as a way to save on energy costs. But how do they work?
Solar hot water systems work by using the sun’s energy to heat water in a tank. The sun’s energy is captured by solar panels, which are generally installed on the roof of a house. This heated water is then stored in an insulated tank, ready for use when needed.
In this post, we’ll take a look at how a solar hot water system works and how you can benefit from using one. This blog will also outline the different types of solar hot water systems so that you can make an informed decision about which one is right for you.
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How Does a Solar Hot Water System Work?
Solar hot water systems typically consist of a solar collector, a storage tank, and a backup system. Solar collectors are usually installed on the roof and work by absorbing the sun’s rays and converting them into heat. This heat is then transferred to the water in the storage tank, usually located inside the home.
The heated water is then used for household tasks like showering, doing laundry, and washing dishes. Solar hot water systems rely on solar panels, this type of system is often used in warm climates where there is an abundant amount of sunlight.
In Australia, solar hot water systems are a popular choice for domestic hot water. They are efficient and can save you money on your energy bills.
One common concern about solar hot water systems is that they might run out of hot water on cloudy days or during the winter months when the sun’s rays are weaker. However, most solar hot water systems are designed with a backup system that uses electricity or gas to heat the water when needed. As a result, homeowners can enjoy a continuous supply of hot water, even when the sun isn’t shining.
The backup system kicks in when there is not enough sun to heat the water in the storage tank. The most common type of backup system is a solar hot water booster switch, which uses electricity to heat the water. Gas-powered boosters are also available, but they are not as common.
Passive vs Active Solar Hot Water Systems
There are two main types of solar hot water systems: active and passive. Active solar hot water systems have pumps and controllers that circulate the fluid in the system and so are more expensive to purchase and install.
Passive solar hot water systems rely on gravity and natural convection to circulate the fluid, making them more economical. Pumped systems are a type of active system. Learn more about these types of hot water systems below.
Active Solar Hot Water Systems
Active solar hot water (ASHW) systems use pumps to circulate the fluid in the system, and also have controllers to regulate the pump and ensure that the temperature in the tank remains constant.
The most common type of active system is the direct circulation system, which circulates water from the tank through the collector and back again. The advantage of this type of system is that it can be used in colder climates where the sun may not shine as much.
Another type of active system is the indirect circulation system, which circulates a heat-transfer fluid through the collector and then passes it through a heat exchanger to heat the water in the storage tank. This type of system is more efficient than direct circulation systems but can be more expensive to install.
Passive Solar Hot Water Systems
Passive solar hot water (PSHW) systems rely on natural thermosiphoning to circulate fluid in the system.They rely on convection currents created by differences in temperature to circulate hot water as necessary.
There are two types of thermosiphoning systems: integral collector-storage (ICS) units and batch solar water heaters.
ICS units usually look like a conventional box-shaped solar water heater, with an insulated storage tank inside an outer shell. Batch solar water heaters have a cylindrical storage tank outside the box, with a collector around it.
Both types rely on gravity to circulate fluids and they can be used in any climate. However, they are less efficient than active systems and can take longer to heat up in cold weather. As the most common type of solar hot water system, it’s the one used when comparing solar hot water and gas heating systems.
Pumped Solar Hot Water Systems
Pumped solar hot water (PSHW) systems are a type of active system where pumps circulate fluids, but they also have additional features to increase their efficiency.
One type of PSHW system is called a drainback system, which includes a reservoir filled with non-toxic glycol that acts as a heat-transfer fluid. When sunlight hits the collectors, it warms up the glycol, which circulates through pipes to a heat exchanger where it transfers its heat to water in the storage tank. The glycol drains back into the reservoir when there is no sunlight, so there is no risk of it freezing and damaging the collectors or pipes.
Another type of PSHW system is called the antifreeze system, which uses propylene glycol as a heat-transfer fluid. Propylene glycol does not freeze as easily as water, so it can be circulated even in very cold weather without damaging the system.
Types of Solar Hot Water Systems
There are three main types of solar hot water systems on the market today: flat plate, evacuated tube, and integrated collector storage. Let’s take a closer look at each one.
Flat Plate Solar Hot Water Systems
Flat plate solar hot water systems have been around the longest and are the most common type of system in Australia. They consist of a metal box (the collector) which is usually installed on the roof.
Inside the box is a dark metal plate that absorbs heat from the sun. Water circulates around the plate, absorbing heat as it goes. The heated water is then stored in a tank, ready for use.
Evacuated Tube Solar Hot Water Systems
Evacuated tube solar hot water systems work in a similar way to flat plate systems, but they are more efficient due to the design of the collector. The collector consists of a series of tubes, each of which has a vacuum inside (hence the name “evacuated”).
This vacuum creates an insulating barrier which prevents heat loss, meaning that more heat is transferred to the water passing through the tubes.
Integrated Collector Storage Solar Hot Water Systems
Integrated collector storage (ICS) solar hot water systems are a hybrid between flat plate and evacuated tube systems. Like flat plate systems, they have a metal box collector which is installed on the roof.
However, instead of a single metal plate, the box contains a series of tubes (hence the name “integrated collector”). ICS systems are more efficient than flat plate systems but not quite as efficient as evacuated tube systems.
There are many benefits to using a solar hot water system. If you’re looking for ways to save money on your energy costs, help the environment, and increase the value of your home, a solar hot water system is definitely worth considering.
If you’re considering getting a solar hot water system, make sure to do your research to find the right type of system for your home and needs. When making your decision, be sure to consider factors such as your climate (solar hot water works best in sunny climates), your budget, and your energy needs.
For more information about solar hot water, check out our other blog posts or contact us today!
Why Should I Get a Solar Hot Water System?
A solar hot water system can save you money on your energy bills and help reduce your carbon footprint. In Australia, around 15% of a household’s energy usage comes from heating water. Installing a solar hot water system can therefore make a big difference to your energy bills.
Solar hot water systems can also reduce your carbon emissions as they rely on renewable energy from the sun, rather than fossil fuels such as gas or electricity.
Do Solar Hot Water Systems Still Work on Cloudy Days?
Yes, solar hot water systems work on cloudy days, but cloud cover will reduce the amount of solar radiation that reaches the earth’s surface, making it more difficult for solar panels to absorb heat. As a result, solar hot water systems may not be able to heat water as quickly on cloudy days.
Additionally, cloud cover can also cause the temperature of the water in the storage tank to fluctuate more than on clear days. However, despite these challenges, solar hot water systems can still provide an efficient and eco-friendly way to heat water on cloudy days.
Do Solar Hot Water Systems Still Work in Winter?
Yes, solar hot water systems can still work in winter, though they may not be as effective as in summer. This is because solar hot water systems rely on sunlight to heat the water, and in winter the sun is not as strong.
However, most solar hot water systems are designed with this in mind and have a backup system, such as a gas or electric booster switch that kicks in when the sun isn’t shining as brightly. So while you may not get quite as much hot water from your system in winter, it should still work effectively.
Does Solar Hot Water Run Out?
Solar hot water systems are designed to store hot water so that you can have a continuous supply, even when the sun isn’t shining. So, whether it’s a cloudy day or a cold winter night, you can be confident that your solar hot water system will continue to provide you with hot water.
This article is published in good faith and for general informational purposes only. JFK Electrical does not make any warranties about the ongoing completeness and reliability of this information. Always seek personalised advice on solar energy to ensure any recommendations suit your property and scenario.
John Lyons, the owner of JFK Electrical Solar & Air, started his career in the electrical industry in 1997. With years of experience gained in the industry across multiple continents, he relocated to Australia and decided to specialise in solar and air conditioning. After deciding he wanted to be closer to his family, John began his own local electrical business in Mandurah, using his extensive knowledge and training in the industry. At JFK, John’s number one goal is to provide tailored solutions to his customers. And thanks to his experience and commitment to his customers, JFK Electrical is now one of the most trusted local businesses in Mandurah for solar and electrical services.