Richard Prince, Business Development Director at Advance Appliances, provides an insight into Thermal Stores and looks at how they differ from standard cylinders.
Q. How does a Thermal Store Work?
A Thermal Store works by taking the energy within the cylinder and passing it through an internal coil or heat exchanger to provide mains pressure hot water and water for space heating. A typical store temperature for a Thermal Store would be around 75-80°C, this means that an instantaneous potable hot water supply can be achieved via the coil or heat exchanger without requirements for safety relief valves because of the small volumes of water being heated.
Q. What is the difference between a Thermal Store and a standard hot water cylinder?
A Thermal Store works very differently to a standard vented or unvented cylinder, in those types the water heated within the cylinder is the water which will be supplied to your potable hot water outlets and then replaced with cold potable water from your mains supply. Within a Thermal Store you heat the body of water within the cylinder and use the energy within that water to provide instantaneous potable hot water via an internal coil or heat exchanger.
A Thermal Store can also provide space heating, either via an internal coil or heat exchanger or by using the body of stored water directly in the heating system, this gives the ability to create either an open vented or sealed type heating system.
Q. Does a Thermal Store require a heat source from renewables or can they work with all kinds of heat source?
A Thermal Store is probably the most versatile when it comes to heat inputs, conventional heat sources such as a gas boiler or an electric source such as PV solar can be connected without issue and will perform as normal, however on top of this you can utilise almost any additional heat source.
Thermal Store cylinders can accept heat input from solid fuel systems such as log burners and stoves, solar power from either solar thermal or solar photovoltaic, Oil and LPG Boilers and biomass systems to name a few of options available on the market.
Q. Are there any limitations on the number of points of use (taps, baths, etc…) from a Thermal Store?
As a Thermal Store offers instantaneous hot water to taps and showers they can provide hot water for multiple outlets at any one time providing maximum comfort to homeowners. Manufacturers will provide a sizing calculator on their websites and specification sheets to help size the correct cylinder for the property, this is based on the number of outlets within the property and also the number of occupants.
Q. What kind of flow rates will I get from a Thermal Store?
As a Thermal Store works on mains pressure to provide instantaneous hot water flow rates can be very high in comparison to alternative solutions. Manufacturers will take into account the size of internal coil or heat exchanger and advise an optimum flow rate for the specific model, this generally sits at around 3 bar and 25lpm in line with an unvented cylinder performance. Like any mains pressure system, flow rates are dependant on incoming mains flow.
Q. Is any servicing required?
Servicing of any water heater is required to ensure that the system is working efficiently and within safe working parameters. Manufacturers will generally require an annual service and inspection of the cylinder in line with their warranty. Servicing and maintenance should also be carried out using manufacturers genuine spare parts, as a Thermal Store works under different parameters to a standard vented or unvented cylinder the components used will have different temperature controls and settings.
If you are to replace controls with lower temperature controls you will affect the performance of your Thermal Store. Service intervals and logs are generally found within the back of the manufacturers installation guide and should be kept with the cylinder.
Q. What kind of warranties are available?
Like all cylinders a Thermal Store can be built with different processes and materials and carry a manufacturer’s warranty to suit this, typically a Thermal Store warranty will be between five and 25 years which is standard practice across all cylinder types that we see on the market today.
