We have a crises in the delivery of clean energy across the UK. The experiance and knowledge through Thermmaltricity International Consultants is hear to help

As with the rest of the web site, I am re writing a lot of what I wrote over the past 10 yrs as had become outdated and irelitive to whats more important today.

The NEW information I will be providing over this year is about the cost of heating a cylinder of hot water (now estimated at £500 for a family of 4) and how to reduce this over the year.

For much more than just reducing HW costs, go to my other pages covering my multi fuel thermal store (ThermoSolar) that provides both heating and hot water.

 This page is focused on just the hot water side of a homes and business needs, which has been ignored until now.

By now the majority of home owners as well as businesses have been alerted to the increase gas and electricity prices as from 1st April 2022 due to many reasons, but accelerated by the Russian invasion of Ukraine.

This is the first of many designs that uses both flat plate collectors like AES made in Scotland or an imported one from Austria through a UK importer/distributor.

Having spent 5 yrs in Cyprus where 99% of solar thermal HW only systems are of a Thermo Siphon nature, I see no reason why this simple, no pump concept cannot be applied across the UK.

Let’s take this photo above as one of many of my examples I have installed over my 30 yrs since I began to invest in solar thermal.

Imagine this building as shown on top of a roof of a Spanish villa, is the inside of your loft

This is the first step, to be able to have the space in the loft, with standing room if possible and a boarded area over an area, where walls below can support the Pre Heat buffer Cylinder full of a water/glycol mix.

For the collector to work as a Thermo Siphon, the expanded hot water out of the collector on the top left has to be as close to the position of the top of the pre heat cylinder to work.

As the weight of the cooler water in the store feeds the bottom of the collector (bottom right hand side), the heated water rises as its heated up in the 1.8m2 collector copper exchanger behind the glass. With less water pressure at the top compared to the bottom, also helps the process.

Verticle Model

From top to bottom

A. Is the open 22mm water feed pipe plumbed into an F&E tank

B. Is the hot water in from a flat plate collector as the water heats up, then expands into the buffer

C. is one of 2 cold water feeds to the bottom part of the flat plate collector

D. Is the pre heated cold water out via a TMV, set at 30c, for a constant temperature back to the cold feed of your existing unvented cylinder

E. Is cold mains water diverted from your existing unvented cylinder located in the airing cupboard

F. Is 2nd of 2 cold water feeds to the bottom of the collector as well as a drain TEE off.

G. Is a vent pipe that bends over the F&E tank

Buffer tank overall dimensions with 50MM sprayed foam is 1,100mm x 475Mm diameter


Horizontal pre heat buffer cylinder This model is only if you do not have the height for a vertical model.

This design is less efficient in HW transfer due to the fact the bottom half could be cooler than the top half. But is still of a huge benefit on very long sunny days.

A. Cold mains water in, via a 2L expansion vessel

B. 22mm open vent and feed pipe to a F&E tank to be installed above

C. hot water in from solar collector

D. Pre heated cold water out to existing unvented cylinder cold feed in

F. Cold feed to bottom of solar collector

G. Drain valve

Buffer tank overall dimensions with 50MM sprayed foam is 1,100mm x 475Mm diameter

The two new low running cost solar thermal pre heat options, is for the thermal store to be separate to the flat plate collector outside on the roof, working as a thermo siphon system protected by a water/glycol fluid mix via the F&E tank.

The 2nd option is for the solar collector to work as a pumped system requiring a circulating pump and a solar controller with an added solar sensor pocket in the store.

Both options provide pre heated water at mains pressure to be supplied into your existing unvented cylinder or Combi Boiler through a temperature mixer valve (TMV). More details will be added, as I bring the components together along with installation info.


A re designed Polypropylene thermal store An alterntive to a stainless steel thermal store

This latest addition to my growing range of Thermal Stores manufactured by Harlequin Oil Tanks in Scotland is in the early stages of being re designed to except a new type of heat pipe tube collector, which shuts down at 85c to prevent over heating.

The flow and returns between the collector exchanger at the top of the tubes will be through the top of this vented 150-200L buffer cylinder.

No other back up will be included but is still offered as a thermo siphon as well as a pumped system, if the roof area is at a distance to where the buffer is located.