Denise Rooney
We are on a mission to make our company as sustainable as it possibly can be – powering our low carbon future. We have been running on 100% renewable electricity for many years. Last summer we filled our roof with solar PV panels, which have been performing well. Since August we’ve generated over 10 MWh. During most of our office hours, we are producing more electricity than we require to run the building.
Our oil heating system was the next obvious step. The existing system was an oil boiler, and it seemed like an air-source heat pump would be a great way to reduce our carbon emissions. THE GOAL: to make us net-negative for CO2 (at least for our daily operations).
The incentive here was both to improve our environmental performance and to make better use of the solar power we generate, as we do not get paid much for exporting it to the grid.
While our local area can get pretty cold, modern air source heat pumps can operate effectively down to low outside temperatures. Of course, we chose the coldest week of the year to do the installation with outside temperatures of -10 °C, but it was well up to the challenge.
In the short run, ground-source pumps would have been more efficient (and would have enabled larger RHI payments). They would be more expensive to install and more difficult to maintain due to the limited amount of land surrounding our headquarters.
We already had underfloor heating on the lower floor, perfectly suited for a heat pump. Several radiators on the upper floor needed to be upgraded, but this was done with minimal disruption.
The Final System
The final system actually gives us more space inside the building, as the main unit is now outside.
Cheaper than the current oil price
We’re already averaging a COP of around 3.4 (1 unit of electricity gives us 3.4 units of heat). It’s already looking cheaper than the current oil price.
That’s before you work out the benefit of us generating ‘free’ solar energy. Today is a partially cloudy day in late February, and we still generated over 50 KWh. The system never dropped below 2 KW between 9:30 a.m. and 4 p.m., so the vast majority of the electric requirements for heating will have come from the panels.
