Find a Back Boilers
If you are looking for an excellent source of alternative energy, then a back boiler is just what you need. It is often used to supplement conventional heating systems in homes and small businesses where demand is greater than the amount of fuel used by a central heating system. A back boiler is commonly found in solar panel installations because they use this extra energy, which would otherwise be wasted, to warm various parts of the home that a conventional boiler would generally heat. In straightforward terms, it works on the principle that if two heat exchangers are in operation (one low-temperature heat sink and one high-temperature heat source), the combination can be more efficient than either one alone. Often you will find that if you have a renewable energy source such as solar panels installed, you do not have enough excess to run your central heating system efficiently, so installing a back boiler allows you to put this 'extra' energy to good use.
https://www.backboilers.co.uk/