Thermal energy stores

- reduces the need to buy more fossil fuels

- helps renewable heating systems work more efficiently

- combine with a secondary heating source

Thermal stores or thermal energy storage are used to store and manage renewable heat until it is needed.

Heated water is usually stored in a large, well insulated tank/ cylinder often called a buffer or accumulator tank.

Usually thermal stores contain on or more heat exchangers often in the form of internal coiled pipes or external flat-plate heat exchangers, sometimes thermal stores may also include an electric heating element, such as an immersion heater.

A purpose-built thermal store can take inputs from several different technologies if it has been designed and sized to work with the different technologies, it could store heat from a biomass boiler, solar heating system or a heat pump.

Thermal Stores can provide:

• Both space heating and mains pressure hot water
• Only space heating only (which may be the case with a heat pump system)
• Only hot water only (common in the case of a solar water heating system)

You can use the full potential of a thermal store when you use it to store and manage several different heat inputs and outputs, you could let it use your excess solar heat for space heating and act as a preheat heat pump to supply your hot water.

Benefits of a Thermal Store

Types of Thermal Stores

Thermal stores can work with an individual renewable energy source or can work with a combination of different renewable heating technologies. They can also be used to store renewable energy  from a convention boiler or an immersion heater. 

They work excellently with wood-fuelled biomass boiler, heat pumps, wind energy and solar water heating systems.

Like most things there are several different thermal stores available on the market designed to suit different technologies better. Here's a highlight of some of the Thermal Stores available. 

Thermal stores work very well with solar water heating systems as you can use the solar thermal heat to heat up space inside you home, as well as heating water. When it is a sunny day, a solar thermal array may harvest far more heat than you demand, combine this with a thermal store than you can put that excess energy to good use in the future.

Thermal stores can also be designed to prioritise solar thermal heat above any other sources of heat. So when it is a sunny day you can set the thermal store so no other heat source will come on.

Thermal Stores for wood-fuelled heating

Thermal stores are extremely important for the efficiency of biomass heating systems, technology like log burners, which are designed to burn logs at high levels of efficiency, rather than small quantities throughout the day. A thermal store helps reduce the time between lighting the boiler/ stove and the demand for hot water by storing the hot water for use later.

Thermal stores designed to be compatible with log burners/ wood-fuelled heating systems normally provide heating for space as well as domestic hot water, so they tend to be quite large. Thermal stores which are specifically designed for wood-fuelled energy are often referred as accumulators or buffer tanks. They typically hold between 500 to 5,000 litres of water and are able to store hot water for days if properly insulated.

The size of the thermal store you go with for a wood-fuelled heating system will depend on a few factors, the most important one is what type of wood will be used? A pellet boiler can be paired easily with a smaller thermal store, it can work quite quickly with the changes in heat demand. Whereas a log boiler designed to burn logs in batches will require a larger thermal store to store all the heat from the log burner.

Combining technologies

Thermal stores allow you to link up several different sources of heating systems, you could have a wood burning pellet/ log stove and a solar water heating system. This is particularly a beneficial combination, it will provide you with hot water in the summer without having too light the stove.

Costs

Thermal stores such as hot water cylinders are found in millions of homes, but the cost of connecting it to renewable sources can range from a few hundred pounds to over a thousand, depending on how many inputs you’re looking for, and how they will be controlled. If you are interested in having your own thermal store it will definitely be worth having us take a look and show you your options, you can contact us here.