Hot water storage tank

An efficiently insulated tank can retain stored heat for days, reducing fuel costs.

[1] Hot water tanks may have a built-in gas or oil burner system, electric immersion heaters.

The most typical, in the domestic context, is a fossil-fuel burner, electric immersion elements, or a district heating scheme.

[citation needed] Where access to the inner tank is a priority (in cases of particularly aggressive minerals or oxygen levels in the local water supply) the PUF can be applied in encapsulated form, allowing the removal of insulation layer for regular integrity checks and if required, repairs to the water tank.

This technology is now making it possible to store thermal energy is small to medium-sized systems for weeks without any significant heat losses.

Because conventional hot water storage tanks can be expected to leak every 5 to 15 years, high-quality installations will include, and most US building/plumbing codes now require, a shallow metal or plastic pan to collect the seepage when it occurs.

Calm, undisturbed water is a relatively poor heat conductor when compared to glass, bricks and soil.

In this case there must not be vertical metal plates or tubes as they would conduct heat through the water layers, defeating the purpose of stratification.

This drop in temperature causes the thermostat to switch on the electric heating element at the bottom of the tank.

If the thermostats in such a system are reversed - warm feed from the top, hot from the center - it may not only affect the energy efficiency of the system, feeding scalding water to a domestic hot water outlet may be dangerous, or if directed to warm-feed washers damage them beyond repair.

On the other hand, water stored below 60 degrees Celsius can permit the growth of bacteria, such as those that cause Legionnaire's disease, which is a particular danger to those with compromised immune systems.

Two red paralleled hot water storage tanks connected to a wood-fuelled furnace .
A hot water storage tank where one of the heat sources is solar heating A, that is sent into the hot water storage tank via a smaller pump B (circle with triangle) and the heat exchanger spiral in the hot water storage tank. The other spiral C can be used for a e.g. oil-fired boiler or a wood burner. At D the hot water gets out and domestic cold water is sent back at the bottom at E.
A hot water storage tank where one of the heat sources is solar heating . Almost the same example as above, but in a domestic habitat.