It was fantastic to receive the feedback from a customer who incorporated a thermal store in their energy scheme. With the south facing bungalow and according to Met-Office data, the property in Pen Llŷn receives as much sunshine as Cornwall, so the homeowner maximised the solar benefits.
BACKGROUND
The twelve-year-old 4kW solar system had performed well and demonstrated the benefit of free energy from the sun particularly during the summer diverting excess power to the immersion heater to give free domestic hot water. With the increase in oil and electricity costs, the homeowner decided to expand their solar system to generate additional power and benefits.
SOLUTION
The solution came in the way of investment in an upgrade comprising a further 4.5kW Solar Edge PV, a Tesla 13.5kWh ac battery, a McDonald Water Storage 1,000 litre thermal store, with two 3kW immersion heaters operated by Myenergi EDDI power diverters.
The thermal store loses approximately 2°C overnight, so an insulated cabinet will be constructed to minimise heat losses.
The system is designed to utilise the power of the sun to primarily provide free electricity and secondarily provide free heating and domestic hot water (DHW) and was commissioned at the start of September and works automatically with the existing 12kW condensing boiler as backup on cloudy days.
When it came to the functionality, during September it reached 84°C on solar only but we had only occasional demand for heat on cool evenings, the expected winter operating temperature is 60°C – 65°C with solar contributing to base load during sunny periods. Our bungalow only requires a maximum flow temperature of 60°C at 0°C outside as it has oversized radiators.
Monday 16 October started cloudy then hazy sunshine 10°C east wind 18 – 25mph overnight falling to 8°C, the morning 11°C with wind increasing to 25 – 35mph from the south-east. The battery was fully charged at 13:00 and the thermal store had reached 62°C at 17:00 via the Myenergi EDDI power divertors, the boiler cutting in for 10 mins to take it to 63°C.
Excepting 40% of the grid power for the 8.5kW electric shower, the system has provided electricity and heating to 22°C during the evening from 18:00 – 21:30 and in the morning 21°C from 07:00 to 09:30 the thermal store falling to 52°C thus giving us free electricity and heating from the previous day’s sunshine.
TESTIMONIAL
Roy M., Homeowner
“Results from September to November indicate that during the summer we will be free of energy charges, the above scenario is where we will benefit during the spring and autumn. The battery fully recharges even on cloudy days.
The thermal store opens up the possibility of using an air source heat pump on an EV overnight charging tariff of 9p/kWh (e.g., Octopus Go) so heat is provided at 2.5-3p/kWh.”
Wayne Hyde
Marketing and Project Manager
Having been in the cylinder industry for nearly 20 years, in both product and marketing roles, I have extensive knowledge of all aspects of hot water storage, from domestic through to commercial applications, including vented, unvented and thermal store solutions.
