Secon: Solar water heating systems

As concern over climate change grows people throughout Europe and beyond are looking toward renewable energy technologies to meet an increasing proportion of their energy , requirements. Over 160 countries have made a commitment to reduce greenhouse gas emissions and the UK government is committed to securing 10% of energy requirements from renewable sources by 2010.

There are two ways in which solar radiation can be harnessed:

Solar thermal collectors typically comprise of 3 types:

• Unglazed plastic collectors used for swimming pool applications where the temperature requirements are lower than for domestic hot water production.

• Flat plate collectors containing a specially treated absorber plate to maximise solar gain. The collector is glazed with either solar glass or plastic and is highly insulated to minimise heat losses.

• Evacuated tube collectors in which the absorber plate is enclosed in an evacuated glass tube. These collectors can operate at higher temperatures due to the vacuum insulation and are usually more expensive.

Systems are Straight forward to install, reliable and durable. The collectors work during overcast days when there is no direct sunlight. Heat from the sun is transferred to water contained within the collector and circulated to a special solar cylinder where it can be topped up to a useable temperature when required by a conventional boiler or immersion heater.

Differential temperature controllers

A differential temperature controller constantly monitors the temperature in the solar collector and compares it with the temperature in the cylinder. When the collector is hotter (typically 4 deg C) than the cylinder the controller switches on the circulating pump and heat is transferred. Resol have produced a range of differential temperature controllers since 1977 and are now the largest manufacturer in Europe, offering the most comprehensive range of solar control equipment available anywhere.

The market place

It is thought that over 50,000 systems are currently in use in the UK and the market is entering a period of sustained growth with an increasing number of local authorities, housing associations, architects and builders specifying solar thermal systems. This in addition to the increasing number of private individuals, estimated at over 3000, having systems installed each year. The European market is expected to grow at around 20- 25% annually over the next 5 years although some form of incentive or legislation is still seen to be required before the UK gathers the same momentum. Secon is UK distributor of Resol whose products are widely used throughout mainland Europe and the UK. In addition to differential temperature controllers Secon also supplies" the FlowCon solar group which contains all the major solar primary circuit components including the controller in a pre- wired, pre-insulated package. Installation of the FlowCon requires minimum effort and ensures optimum system performance.