Harnessing Solar Energy for Efficient Heating
A Ground Source Heat Pump Solution in Marden, Kent.
When we were approached by a customer seeking an efficient heating solution for three separate dwellings on their farm in Marden, Kent, we knew this project would require a tailored approach. The challenge was to design a heating system that could effectively serve multiple properties while maximizing the benefits of an existing solar farm on the site.
Maximising Solar Potential
The customer had already invested in a solar farm, installed by a company that supplied and installed the equipment in exchange for the Renewable Heating Incentives (RHI). Under this arrangement, the customer could purchase electricity generated by the solar farm at a rate of 6 pence per unit. With this in mind, our task was to develop a heating solution that would seamlessly integrate with the solar farm, providing reliable, energy-efficient heating across the farm’s three distinct properties.
Planning and Installation
The farm consisted of three main buildings: the ‘Farmhouse,’ where the customer resides, the ‘Oast House,’ which is rented out for residential use, and the ‘Barn,’ used as office space. To ensure optimal performance and efficiency, we began by conducting a comprehensive assessment of the existing heating systems in all three buildings. Based on our findings, we implemented various upgrades and recommended simple insulation improvements to enhance overall energy efficiency.
To accommodate the new heating system, we designed a timber-framed plant room built to our specifications. This plant room would house all the necessary heating and hot water equipment. Central to the system was the installation of a 45kW Thermia Mega M three-phase Ground Source Heat Pump. This powerful unit was selected for its ability to efficiently serve all three properties while making the best use of the solar farm’s electricity.
Each property was individually metered for heating and hot water usage, allowing for precise monitoring and billing. We also installed pre-insulated pipework to ensure minimal heat loss during distribution.
Impressive Results from the Heat Pump Installation
The performance of the Ground Source Heat Pump has exceeded expectations. During the summer months, the heat pump has been able to generate an average of 3.5 units of heat for every 1 unit of electricity consumed. This efficiency means that the system can provide 100% of the hot water needed across all three properties using minimal electricity.
In the winter months, the system’s efficiency increases even further. The heat pump produces over 4 units of heat for every 1 unit of electricity used, delivering both heating and hot water at a fraction of the cost compared to conventional systems. For comparison, a standard immersion heater typically returns only one unit of heat for every unit of electricity used, highlighting the significant energy savings achieved through this installation.
Client Feedback
"Our pump is rated at 45 KWth, this means our Tier 1 ceiling is 45 x 1314 = 59,130 (please check this before publishing)
The input electricity of the scheme September - September was 21,383 KWh.
Output was 68,830 plus 13,124 (hot gas) = 81,954.
Less input electricity 81,954 – 21,383 = 60,571 KWh of generated sustainable heat.
We do get paid on everything that comes out of the main output meter though, so we are actually paid for whole 81k KWh. However, the cap comes down at 59130 units, and the Tier 2 payments are much less generous. I think that this means we will earn about £6k/pa [index linked] for 20 years. Less maintenance and repairs, and also less electricity costs, this is a modest but useful return on our investment.
To us, it is important that it is index-linked. So this is effectively a government bond – a safe form of saving.
The other thing is that we are currently charging our tenants for heat and hot water as metered via the system. We have just raised this price from 5p to 6p, which we still think represents good value for money. The hot water supplied, we work out what it has cost to heat, and allocate that cost based on how much each has consumed.
As the heat pump is used to sell heat to our customers, we were able to recover the VAT, as our business is registered as a farming/ power generation company. As you are aware, we benefit from cheaper electricity costs from our solar array."
