Case Study: Solar Thermal - Solar Water Heating - for Hairdressers.

Solar Thermal Energy, more commonly called Solar Hot Water is one of commonest ways people move into the use of renewable energy. Not only has it got one of the clearest cost benefits for domestic use, it is even more appropriate for commercial use where hot water is routinely required.

We were approached by a hairdressing salon that wanted to know if a solar hot water system could lead to real energy and thus cost savings or whether it was a high cost way of having green PR. The key statement was that it had to have a real cost benefit!

Looking at the ongoing requirements for hot water in the salon, we were able to identify very quickly that the need for hot water was effectively constant and that the main period of use was generally within the peak period of solar energy.

This gave us significant advantages over a domestic system where the hot water generated during the day has to be stored for use in the evening. Once the hot water tank is full, the rest of the solar heating is wasted as the system is set to shut down.

So we looked at the optimum system:

• During the peak (for sun) summer period, the panels would generate near enough all the hot water requirements.
• We planned for solar power being used almost exclusively during May, June and July.
• There was a drop off in trade during August which meant that the reduced amount of solar heating might mean that August was an exclusive solar heating month.
• A traditional heating system would still be needed to maintain hot water heating during the lower levels of solar energy during the rest of the year.
• When the solar heating system wasn't able to provide all the heat, it was at least going to keep working to provide pre-heating. This meant that we woudl look very carefully at the hot water settings to ensure the heat that the solar panels provided wasn't lost.
• The last, but equally important considerations were the roof area, how many panels could be fitted and the amount the salon was prepared to invest.

The system that satisfied all requirements - including roof space and price - was a 4 panel system with a 150 litre hot water cylinder.

The hot water cylinder was about 1/2 the size of that recommended for a similarly configured domestic system, however it was considered that it would also suffice should additional roof panels be added.

• 4 x CU210 Sammler flat thermal panels 
• flat roof mounting 'A frame'
  
• Resol controller including temperature sensors etc
• Solar Pumping Station - the system controller that includes a digital differential temperature controller, circulation pump, valves, gauges, filling & draining valve, all pre-assembled with pre-formed insulation jacket
• 150 litre dual coil horizontal hot water tank with electrical immersion back up.
• Stainless steel ready insulated flexi pipe