Applications and Utility
There are lots of ways that solar thermal energy can be used. The most common application is to heat water for washing and cleaning.
This can be on domestic, commercial and industrial scales, with public buildings, businesses and home owners cited as being in the best position to maximise the opportunities available. Hotels, hospitals, educational buildings, offices and factories are all typically looking to make savings to their running costs and often have very large demands for hot water provision.
We have extensive experience in providing solutions for projects of this kind and due to the modular way in which the Lazer2 collector can be increased in number to suit energy demand characteristics; it is ideally suited to cater for both the smaller domestic installations as well as large scale commercial projects.
Other suitable applications include heating swimming pools and other large volumes of water such as for industrial processes.
The LaZer2 collector can be utilised in many ways. Typically it is used to
indirectly heat a stored water volume in a vessel via an internal coil, or it i s
used to heat the secondary water volume via a heat exchanger. In some
instances it is used to heat a heat storage medium/volume which in turn
has further exchanges to either heat exchangers or extraction coils.
Phase heating of different volumes of water is also possible depending on the application priorities and this is often referred to as pre-heating or buffering.
A typical solar hot water heating system consists of an indirect hot water cylinder, with internal heat exchange coils fitted for each of the heating circuits, as can be seen here in this diagram.
An alternative is to have a pre-heating/
pre-feeding arrangement, whereby two vessels are installed in tandem.
In this arrangement the flow of water passes through both cylinders, with heat input occurring in each in turn before going to the outlets (taps/showers).
An example of how this can be achieved is shown here. Heating swimming pool s with the LaZer2 solar thermal system offers huge savings on energy costs compared with conventional fuels used to do this, and so these systems can achieve very short payback periods.
The typically seasonal use of
swimming pools in northern Europe makes pool
heating a very suitable application for this technology.
A layout showing the pool pumping and filtration
equipment required for all swimming pools, coupled
with an inline solar heat exchanger and a conventional inline boiler heat exchanger can be seen here.
The setting on the boiler system in this example would ensure the desired comfort level is reached whenever owner/user wishes to take a swim.
The LaZer2 solar thermal system is able to utilise
all available solar yield to heat the pool water and satisfy the boiler temperature control thermostat. This
set up allows the heat input from the sun to be used to off-load the work otherwise done by the boiler,
and to prevent additional heat from the boiler from being required for the majority of the time.
The LaZer2 system is versatile and can be used for all sorts of purposes. Heat stored for other purposes is common and bespoke service systems can be designed to lower running costs and offset CO2 for many different client demands and objectives (Heat). Heat stores are popular for many reasons but they are not ideally suited for providing the best performance for a standard hot water system. Advantages they do have include hydraulic separation and multi utility flexibility.
Although some clients wish to use solar thermal technology to provide space heating, this application is not well suited to the characteristics of solar thermal technology.
This is partly due to the nature of solar gains being most abundant during the low demand periods for space heating.
The ability to achieve some benefit by contribution towards space heating is easily achievable, however as a viable space heating energy source any solar thermal system would have to be dramatically over sized to satisfy demand during the coldest and darkest winter months, and would therefore be in a constant state of over production during the bright summer and shoulder months.
This strategy of over
sizing a system does not make financial sense, and so unless sufficient demand exists to constructively
utilise the energy available from the system, the additional outlay required for the purchase, installation
and maintenance of an oversized and incompatible system is not advocated.
Where a logical sizing justification exists, it may then, in addition create opportunity to utilise the energy available in alternative but similarly effective ways.
For example; we often encourage our clients to incorporate the capacity to heat domestic hot water when designing a system for heating a swimming pool, as this is a very sensible additional utilisation for the energy that will be available from the solar system.
Typically we look to allocate between 55-85 litres of dedicated stored water to be heated by each m= of LaZer2 collector aperture, each day in an indirect hot water cylinder.
This ratio is capable of producing
between 55-85% of the HW demand anticipated in a domestic
dwelling, depending on the inhabitant’s usage patterns. Although
variations in usage and weather conditions will account for variations in
system performance, the LaZer2 Collector and solar system is capable
of making the most effective use of the solar energy available at any
given time.
It is important to appreciate the capabilities and limitations of a well designed solar system.
Due to our modern expectations and the level of comfort we have become used too, the majority of solar thermal systems are connected to heat water with all available solar energy, whilst a secondary energy source is incorporated to ensure the desired temperature and recovery periods we have become used too are maintained. Solar thermal systems are designed to be super efficient, whilst traditional heat sources generally prioritise effectiveness over efficiency.
As these traditional water heating systems are capable of heating water in a very short period of time and on demand, the heating characteristics of a well designed solar system is sometimes miss perceived as ineffective, immediately following a peak demand period or over night when solar gain is not available.
Many traditional water heating systems have raised expectations by the almost instant release of energy from primarily nuclear power or fossil fuels allowing water to be heated instantly on demand. Quality solar thermal systems take into to account the duration of light energy available and the demand for hot water throughout the year and so are sized to achieve the desired quantity of water heating with the minimal of equipment outlay.
Should an increase or decrease in the hot water demand occur the perceived effectiveness of the solar system can often be affected.
Depending on the priorities set by the client, and using the LaZer2 collector, we can tailor a system to best suit needs of the buildings end users.
Also by working closely with mechanical and electrical consultants we regularly find the right balance between ensuring a building service provision is achieved with the minimal use of conventional fuel sources, thus maximising the utility of free, environmentally friendly solar energy.
