How Does A Hot Water System Work?

Hot water systems are a fundamental part of modern-day living, providing us with warm water for our daily needs, such as bathing, washing dishes, and doing laundry. However, many of us may not fully understand how these systems work, despite relying on them daily.

Essentially, hot water systems are devices designed to heat and store water for domestic use. There are various types of hot water systems available, which we will cover in this article. By understanding how these hot water units work, you can better appreciate their value and importance and take the necessary steps to keep them running efficiently.

The Working Mechanism of Various Hot Water Systems 

Hot water systems work on a simple principle of heating and storing water for later use. The system comprises a heat source, a heat exchanger or storage tank, and a thermostat to regulate the water temperature. In all hot water systems, the thermostat regulates the water temperature and switches off the heat source once the water reaches the desired temperature.

The hot water is then stored in an insulated tank or passes through a heat exchanger before being delivered to the taps or showers. Let's dive into the specifics of electric, gas and solar water system:

Electric hot water systems

Electric hot water systems use an electric heating element to heat the water stored in a tank. The heating element is usually located near the bottom of the tank and is powered by electricity from the mains.

When you switch on a hot water tap, cold water flows into the tank, displacing the hot water at the top and triggering a thermostat to turn on the heating element. The heating element heats the water, raising the temperature until it reaches the set temperature on the thermostat.

Once the water inside the unit reaches the set temperature, the thermostat switches off the heating element to conserve energy. As hot water is drawn from the tank, cold water flows to replace it, and the heating cycle starts again.

Electric hot water systems can come in two main types: storage and instantaneous hot water units. Electric storage heaters store hot water in a tank, while instant electric water heaters heat the water on demand as it flows through a heat exchanger.

Gas hot water systems

Gas hot water systems are a popular alternative to electric hot water systems in Australia, particularly in areas where natural gas is readily available. Gas hot water systems use natural gas or propane to heat the water stored in an insulated tank. The system comprises a gas burner located at the bottom of the tank, a thermostat to regulate the water temperature, and a flue to vent exhaust gases outside.

When the hot water tap is switched on, cold water enters the unit through a dip tube, displacing the hot water at the top. The gas burner then heats the cold water to the desired temperature, and the thermostat switches off the burner once the water reaches the set temperature.

Gas hot water systems come in various types: storage, instantaneous, and continuous flow systems. Storage systems store hot water inside an insulated tank, whereas instantaneous and continuous flow systems heat the water as it passes through a heat exchanger.‍‍‍

Instantaneous hot water systems are more energy-efficient than storage systems as they only heat the water when needed. In contrast, continuous flow systems can provide a constant hot water supply but may require a larger gas supply.

Solar hot water systems

Solar hot water systems use solar energy as the heat source. The collector panels, either flat plate or evacuated tube, absorb the sun's heat and transfer it to a heat transfer fluid, such as water or antifreeze. The heated fluid then passes through a heat exchanger or storage tank, heating the water.

A backup heating element, either electric or gas, is included to ensure hot water is available during periods of low sunlight. There are two specific types of solar water heaters: flat plate collectors and evacuated tube collectors.

Flat plate collectors

Flat plate collectors consist of a flat, rectangular box with a dark-coloured plate that absorbs the sun's heat. The plate is covered with a transparent layer, allowing the sun's rays to pass through and heat the water or a heat transfer fluid.

The heated fluid is pumped through a pipe into a storage tank, where it is stored until needed. The storage tank is usually located above the collectors to allow natural convection to circulate the hot water.

Evacuated tube collectors

Evacuated tube collectors use a series of vacuum-sealed glass tubes to absorb and retain heat. Each tube contains a heat pipe filled with a heat transfer fluid that boils when heated by the sun.

The steam rises to the top of the tube, transferring heat to the water in the storage tank. The process is more efficient than flat plate collectors as the vacuum-sealed tubes reduce heat loss, and the tubes can be tilted to capture sunlight at various angles.

Which Hot Water System Works the Best?

The best hot water system for your household depends on multiple factors, some of which include the total number of occupants, energy efficiency, installation cost, and ongoing maintenance requirements. Electric hot water systems are the most prevalent type in Australia, primarily due to their lower upfront cost.

They are suitable for small households with low hot water usage and do not require gas connections or flues. However, they can be more expensive to run in the long term, particularly during peak energy usage periods. Electric hot water systems also require a larger tank than gas or solar systems to store the same amount of hot water. Gas hot water systems are more energy-efficient than electric systems, making them a cost-effective option in the long run.

They can provide hot water even during a power outage, which is particularly important in areas with frequent blackouts. However, they can be more expensive to install initially and require regular maintenance to ensure safe and efficient operation. Gas hot water systems are also unsuitable for all households, particularly those without access to natural gas or propane.

Solar hot water systems are the most energy-efficient type, using renewable energy from the sun to heat the water. They are particularly suitable for households with high hot water usage and in areas with plenty of sunlight. However, they are the most expensive type to install and may require a backup heating source during periods of low sunlight. Solar hot water systems also require regular maintenance, mainly to ensure the efficiency of the solar collector panels.

Maintenance and Care of Your Hot Water System

Proper maintenance and care of your hot water system can extend its lifespan, improve efficiency, and prevent costly hot water replacements or repairs. Here are some tips for maintaining and caring for your hot water system:

• Regularly check the pressure relief valve: The pressure relief valve on your hot water system is designed to release excess pressure and prevent the tank from exploding. Make sure it is functioning correctly by checking it regularly.
• Drain the tank: Sediment could build up at the bottom of the tank, reducing its efficiency and lifespan. Drain the tank annually to remove any sediment buildup.
• Insulate the tank and pipes: Insulating the tank and pipes could help reduce heat loss, improve efficiency, and lower energy bills.
• Check for leaks: Regularly check for leaks in the tank and pipes, and have them repaired immediately if found.
• Maintain the ideal temperature: Setting the temperature too high can increase the risk of scalding and waste energy. Keep the temperature between 50-60 degrees Celsius.
• Consider regular servicing: A licensed plumber or installer can help identify and prevent potential issues before they become significant problems.

By following these tips, you can ensure the longevity and efficiency of your home's hot water system, save on energy bills, and prevent costly repairs or replacements.

Need Expert Help with Your Hot Water System?

While it's essential to understand how a hot water system works, it's equally important to seek professional help when it comes to hot water installation, maintenance, and repair. Hot water systems involve plumbing and electrical work, which can be dangerous if not carried out by a licensed professional.

A licensed plumber or installer can help you determine the best hot water system for your household, install it safely and efficiently, and provide ongoing maintenance and hot water repairs to ensure it functions correctly. They can also advise you on energy-efficient practices to reduce your hot water usage and lower your energy bills.