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Thermal Stores

You cannot make full use of solar, wood or a heat pump without somewhere to put the heat.

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Hot water storage systems

The hub of a multi‑source system

We have been designing, installing and supplying unique, high‑spec thermal stores for over fifteen years — for the public, for the trade, and for our own renewable heating projects.

Hot‑water storage systems, also known as accumulator tanks or buffer tanks, sit at the heart of our work. You simply cannot make full use of the heat generated by solar thermal, wood heating or heat pumps without a correctly sized, high‑quality store.

We design, import, supply and install tanks from 35 litres to 200,000 litres — covering everything from a wee shepherd’s hut to large industrial buildings and district‑heating schemes. Whatever the scale, the principle is the same: stable heat storage, efficient control, and long‑term reliability.

Its job is simple — capture heat efficiently, store it safely, deliver it reliably. But achieving that takes careful engineering, correct sizing and the right internal configuration.

Heat input strategy

A store will take heat from almost anything

System design begins by identifying which inputs you need. Each has different flow temperatures, output profiles and control requirements.

Core design principles

Seven things that decide whether it works

  • Heat input strategy

    What is feeding it

    Each source has different flow temperatures, output profiles and control requirements. The store must be configured so every one can contribute efficiently without interfering with the others.

  • Coils & exchangers

    Where they sit matters

    Solar coils must sit low in the tank to harvest cooler water; boiler‑stove coils sit high to capture combustion heat; heat pumps need large surface‑area coils for low‑temperature efficiency. Correct placement is what produces stratification — hot at the top, cool at the bottom — which the whole system depends on.

  • Correct sizing

    From 35 litres to 200,000

    Volume follows heat‑source output, the number of sources, hot‑water demand, space‑heating load, the building itself, and how long the store should hold usable heat.

  • Multi‑source integration

    A thermal battery

    A house with an oil boiler, solar thermal and a boiler stove can run all three into one store. It absorbs heat from each and distributes it as required — removing the separate cylinder, simplifying pipework, improving efficiency and leaving room for sources added later.

  • Hot water delivery

    A coil, or a plate

    A DHW coil inside the store suits domestic systems where simplicity and reliability matter. An external plate heat exchanger suits high‑flow properties and commercial sites. Either way, the traditional hot‑water cylinder goes.

  • Controls & logic

    A store is only as good as its control

    Each source has to fire at the right time, prioritise correctly, avoid conflicting with the others, protect the store from overheating, maximise stratification and hold a stable hot‑water temperature.

  • Applications

    Hut to industrial estate

    Multi‑source homes, rural and off‑grid buildings, district heating, biomass, solar thermal, heat pumps, boiler stoves, commercial and industrial sites. From a wee shepherd’s hut to a 200,000 litre accumulator, the principles do not change.

Red Swiss Solartank stores lined up in the workshop
Red Swiss Solartank stores lined up in the workshop

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A stainless steel store in the workshop, ready to go out

Off‑the‑shelf

UK and European manufactured

Copper, stainless steel or carbon steel, offering:

  • Cost‑effective solutions
  • Versatile configurations
  • Hundreds of size, shape and coil options
  • Reliable performance, domestic and commercial

Ideal for standard installations, where conventional sizing and coil arrangements suit the job.

A bare copper store strapped to its pallet before installation

Custom

What we are best known for

Manufactured in copper, stainless steel, carbon steel or hybrid combinations, and built to suit the shape, insulation, pressure and heat‑exchange requirements of the project.

Custom stores allow complete freedom to design exactly what a project requires — no compromise on shape, size, coil layout or insulation.

Custom options

Everything that can be varied

  • Shapes

    • Tall and slim
    • Squat
    • Oval
    • Rectangular
    • Cube tanks

  • Insulation

    • Factory‑fitted jackets
    • Detachable on‑site insulation
    • Foam‑filled on site
    • 50mm to 300mm thick

  • Pressure

    • Vented
    • Pressurised
    • Hybrid systems via heat exchangers

  • Heat exchangers

    • Extra‑long coils for maximum transfer
    • Solar thermal coils
    • Heat‑pump coils
    • DHW coils
    • Section‑separating coils for multi‑zone systems

  • Electrical inputs

    • Immersion heaters for PV or turbine input
    • Direct‑electric DHW
    • Direct‑electric wet heating

  • Specialist heat‑pump stores

    • 32‑metre, ¾‑inch finned copper DHW coils
    • Larger options available

Components & accessories

The parts that go around the tank

  • DTC controllers

    Differential temperature control

    They monitor temperature differences across the system and activate pumps or valves at exactly the right moment — managing gas and oil boilers, solar thermal, heat pumps and boiler‑stove pumps, and protecting equipment from overheating or poor circulation.

  • Loading valves

    Return‑temperature protection

    For biomass boilers and boiler stoves: they maintain ideal combustion temperatures, prevent condensation damage, improve efficiency and extend boiler life. Available with integrated pump groups or standalone.

  • Insulation

    Where the losses actually are

    Extra jackets, detachable on‑site insulation, and injection foam applied on site, from 50mm to 300mm. These upgrades significantly reduce heat loss and improve the efficiency of the whole system.

  • Plate heat exchangers

    45kW to 2000kW

    Stainless steel, for hot‑water production, separating system zones, linking vented and pressurised circuits, and high‑flow commercial DHW. Commonly paired with our stores to deliver powerful, hygienic performance.

From a wee shepherd’s hut to a 200,000 litre accumulator.

We design, import, supply and install thermal stores across the UK — domestic, commercial and industrial.

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