The following pages will cover all my personal experiance gained since 1991 until 2017 related to solar water heating
On returning to the UK in 1998, with the SUNDA agency and later on establishing Powertech Solar Ltd as the exclusive UK importer/distributor of the Apricus and Suntech solar heat pipe brands ( also exported into Europe as well as supplied direct to UK installer companies) the majority of our sales/installations was as a split pumped system for domestic hot water only or solar central heating with our Thermal Stores.
This picture is of a social housing project in Cornwall
This is a typical solar hot water only system seen across Cyprus and Israel with the option at a higher cost, for the hot and cold water tank located in the basement or garage.During my 5 months in Cyprus, there were always water shortages, so this resulted in large cold water tanks also installed on the roof as well as on the ground, but needed a pump. But in Israel, the solar water tanks made of steel and glass lined were designed to except cold water at mains pressure.
This 20 x 30 tube collector installation on the roof of a care home in Sussex/UK, was plumbed into the two 1500 Liter open vented thermal stores made from copper sheet and foam blown spray insulation.
After 5 yrs of flat plate collector experiences in Cyprus, from seeing how they were assembled and installed, I decided that China made evacuated tube heat pipe collectors had an edge over flat plate throughout the year
For me, the future for solar heated water was much more than just heating a tank of water for washing, when it was proven that evacuated tube heat pipe collectors performed well during winter months 30% higher than flat plate collectors, which can never deliver these temperatures over the winter months
The majority of failed solar water heating (SWH) systems was caused by lime scale due to the same potable water being in the water tank and the flat plate collector.
these countries used bore holes and resorvoirs for there water which
has heavy lime deposits.
As the cold water heats up in the copper exchanger thermal collector, the lime starts to coat the internal part of the 12mm copper tube behind the glass. Within 2 yrs the potable water flow through the collectors had almost stoped flowing.
As much as I came up with a solution to solve this issue through a water conditioner, the local cyprus SWH industry was not interested as there survival was replacing collectors on a regular basis.
For those with a swimming pool, a larger solar thermal heat pipe array is the perfect choice, that provides both space heating support and hot water throughout the winter, with the excess heated water to heat the swimming pool, through a 3 way zone valve.
The solar heated thermal store water of 300 liter is circulated through a pool stainless steel tube heat exchanger linked to the pool filter/pump equipment.
The Thermal store is backed up with a gas boiler, if on over cast days, there is not enough solar heat gain
For the domestic hot water, a back up to solar needs to be from a oil/gas boiler. The store water temperature never falls below 25-30c, unlike a unvented cylinder
This was one of 20 new homes being built by a British property developer in 2003, who asked me to supply mains pressure compact thermo-siphon systems with evacuated tubes.
The cold water is pumped from a cold water storage tank located in the garden to the solar pressure tank on the roof. An expansion vessel was also included to limit the water pressure in the solar tank when nobody draws any hot water from the solar system at the height of the hot summer.
All such systems have to allow for the solar heated water to expand by 10% of the volume in the hot water tank, or risk the stainless steel tank splitting open or exploding if the expansion/pressure release valve fails
The majority of my knowledge and on hands solar water heating installation experience started in Cyprus from 1993, after selling my luxury bathroom/kitchen and property refurbishment business in 1991.
My research in solar water heating collectors started 1991 after I designed an alternative to a pressurized hot water tank, we called a Multi Fuel Thermal Store, made of copper sheet and foam sprayed insulation. After working with a copper smith to produce my design, i started to make some early sales, but as soon as the mains cold water temperature dropped to below 8c the thermal store was found to under perform.
The full details of thermal stores can be found under another link.
My decision to set up a new business in Cyprus came about after taking a much needed holiday in 1992, followed by two more visits and finding a British person married to a Cypriot working as a plumber. In 1993, I packed and shipped a 40ft container of a varied mixed range of products to be unloaded into a rented shop in Pathos.
I had planned to be there for 6 weeks setting up the showroom with my own solar collector on the flat roof, with a imported batch water heater with glass tubes on the front of the shop after building an extension to the shop front that represented a UK pitched roof. In those days, there was no digital camera, only film type, which is why I have no early pictures to show, until 2 yrs later.