Types of Domestic Hot Water Systems

Hot water systems deliver a continuous supply of hot water for domestic use at sinks, showers, baths and other fixtures. They are most commonly tank based and use electricity to heat the water. Some systems use solar power to heat the water and a few newer designs also recover waste heat from other processes such as cooling or geothermal energy.

Most of the systems surveyed used a gas storage system (28%), followed by an electric instantaneous system (15%), and an electric boosted solar system (16%). Other types of domestic hot water systems were found in 3% of dwellings.

The cheapest and most common of the systems is the electric storage hot water system. This system uses an element to heat the water and stores it in an insulated tank, which is then supplied to outlets such as sinks and showers. This system typically consumes the most electricity and is less efficient than other types of hot water systems, but can still offer significant savings over other types of electric systems.

Alternatively, electric instantaneous hot water systems do not store any water but heat the water directly from the mains. These systems are typically smaller, more efficient than the storage system, but require an electrical connection and can be more expensive to run. Some modern gas systems use heat pump technology to deliver high efficiency and a low carbon footprint. Heat pumps are more expensive to purchase than traditional gas systems but can significantly reduce your energy bill.

Solar thermal hot water systems are usually a combination of the storage and instantaneous systems. They use solar collectors to heat the water and a small amount of electrical energy to operate the fan and control valves when required. Solar thermal systems are very effective at reducing electricity usage for hot water but they do not offer the freeze protection of traditional storage systems and have difficulty heating water during cloudy or overcast conditions.

Combined heat and power or cogeneration for domestic hot water has been under investigation in some countries. These systems use a small generator to generate electricity and recover the waste heat (typically more than 70%) to both heat the house through hydronics and make domestic hot water. This type of system can provide significant savings over conventional energy use and can offer a good return on investment in homes that cannot be feasibly insulated.

Another alternative to forced air systems is radiant floor heating. Boiler systems circulate water through pipes to plastic tubing in the floors of rooms in the home. This type of heating has many benefits including reduced energy consumption, higher comfort levels and improved air quality as there is no ducting to transport dust and allergens throughout the home. In addition, boiler systems do not produce the air movement that forced air systems do, which can be beneficial in some cases for people with respiratory issues. However, this system is more costly to install and maintain than forced air.

source https://flowlinkplumbing.wordpress.com/2024/08/09/types-of-domestic-hot-water-systems/