Stefan Gautsch of Buderus discusses the potential savings in fuel costs and carbon emissions with solar thermal installations.
In these times of economic uncertainty, businesses are looking with even greater scrutiny at investments and expenditure, many endeavouring to keep the latter to a minimum.
With interest rates at an all time low, does it make sense to put off investment in order to retain savings - especially if the investment will give you a return in the form of cost savings?
Whether savings are available or not, investing in a new heating and hot-water system to replace an existing one which is more than 10-15 years old will undoubtedly deliver significant savings in running costs, especially if fuel prices continue to rise.
Utilising renewable heating technology that works in conjunction with a condensing boiler system is proving to be a popular way of maximising efficiency and economy for many businesses and institutions.
In many commercial situations an investment in renewable energy generally means opting for solar thermal as the most practical solution.
Each solar system must be designed and accurately sized to take into account heat requirements
All renewables by their very nature tend to require space, either for ground works, storage or panels.
However, almost all commercial buildings have an accessible and largely unused roof area where a solar installation could be placed. Used together, solar and modern condensing boilers make an ideal partnership, combining free energy from the power of the sun, with a fuel-efficient boiler to satisfy any additional heat requirements.
A solar thermal system is primarily designed to meet hot-water requirements but in the right type of system can go some way to providing backup for the space heating within a building.
Under ideal conditions, a solar system can deliver up to 60% contribution to the domestic hot-water requirement over the year.
A high-efficiency or condensing boiler will be necessary to meet the majority of the heating load and to supplement the domestic hot-water provision during the darker winter months. It is not simply a case of replacing boilers with renewables.
Fundamentally, each solar system must be designed and accurately sized to take into account heat requirements, demand, and the insulation properties and fabrication of the building. After this there are basically three main reasons why solar should be considered for the heating and hot-water specification - ethics, independence and economics.
It is also a good idea to reduce our dependence on fossil fuels, which, as recent issues between Russia and Ukraine have shown, can leave us at the mercy of world supplies and wildly fluctuating market prices.
While economics is an important issue, we are increasingly finding that reducing carbon emissions is the key factor in the specification of solar systems. This must be an aim for every responsible business as we all have to play a part in protecting the environment for future generations. And the public-sector in particular is tasked by government to lead the way in lowering the carbon footprint of its buildings.
By referring to official records on weather patterns, it is possible to provide realistic assessments of estimated fuel usage and fuel savings from the installation of solar panels, either as a separate system for water heating or as part of a complete integrated heating and hot-water solution.
A roof covered in solar panels is also a visible way of demonstrating a real commitment to reducing fuel consumption and therefore reducing carbon emissions.
To achieve this result, however, it is vital that the system is correctly sized, controlled and commissioned. Accurate sizing requires a realistic assessment of the hot-water demand, which can be achieved by installing metering on a temporary basis.
To maximise carbon reduction, it is also important to avoid wasting the energy, which has been generated. This means ensuring the secondary thermal storage and circulation system is properly insulated and efficiently controlled. The fabric of the building is also an important factor here, and is often where the biggest heat losses can occur.
There is a tendency for solar installations to be oversized to be on the safe side but this is not efficient as heating the domestic water beyond the requirement is wasteful. It could be preferable in some cases to slightly reduce the output from the solar system and blend this with output from the boiler thereby boosting the temperature of the hot water to the required levels.
The overall efficiency of the system is down to the details of its design. The use of sophisticated controls for instance, coupled with other features such as flow regulators and low-flow taps in the domestic hot-water system, will all contribute to the savings. Provision of storage for the heat energy generated by the solar collectors is vital, and will help to ensure that reserves of heat are still available at times when levels of solar irradiation are lower, eg on cloudy days.
Maximising energy efficiency in order to effect carbon footprint and fuel cost savings requires accurate assessment of the needs and circumstances of each installation. It can be complex but help is at hand, and Buderus has a team of technical experts to assist where any advice may be required.