Environmentally-conscious farm cuts carbon emissions and costs with heat pump
20th April 2023
Cronkshaw Fold Farm: Project Overview
Dot McCarthy, the 33-year-old manager of Cronkshaw Fold Farm, buzzes with progressive ideas. Dot’s Lancastrian hill farm became the subject of international attention after one of her “fun” initiatives, hiring out goats for Zoom meetings during Covid lockdowns, became a runaway success.
Dot has also opened “quirky and ethical” holiday accommodations on the farm - including a treehouse - which became the subject of a BBC1 documentary which was later bought by Amazon Prime. Dot’s initiatives all have a shared goal - to raise funds to invest in renewable power technologies to reduce the farm’s carbon footprint.
The traditional business of Cronkshaw Fold, which was passed to Dot from her mother, is the farming of poultry, goats and sheep. The farm also has an organic kitchen garden, manages broadleaved woodland, and keeps honey bees. But the real hive of activity here is the study centre, which is visited by thousands of schoolchildren every year, as well as by students on veterinary and agricultural courses. Subjects covered by the study centre include sustainability and climate change, both very close to Dot’s heart.
Ground source heat pump for heating home and water
Dot originally hoped to take the farm off-grid by installing a wind turbine, but this was refused planning permission. Moving to Plan B, she had solar photovoltaic panels and Tesla Powerwalls installed to generate and store electricity on site. These power the study centre, holiday lodges, and the six-bedroom farmhouse which is home to three generations of Dot’s family. To keep the large farmhouse warm and provide plentiful hot water through bitter Lancastrian winters, Dot chose another clean energy source, a ground source heat pump (GSHP).
GSHPs can operate as a standalone unit or in conjunction with a complementary heating system. GSHPs use only a small amount of electricity and work well all year round because the under-surface ground from which they extract natural heat remains at a fairly constant temperature. GSHPs can also provide a cooling function during spells of hot weather by transferring heat energy from the home into the cooler ground.
The GSHP specified for this task was a 27-kilowatt version of the Viessmann Vitocal 350-G. This is a highly-advanced, high temperature heat pump for larger residential, light commercial and light industrial properties that offers convenient DHW heating. With flow temperatures of up to 70°C, thanks to its EVI compressor, the 350-G is ideal for modernisation projects with radiator heating systems. Dot was happy with this recommendation as her previous, extensive online research had convinced her of the calibre of Viessmann’s heating and cooling solutions.
The Vitocal 350-G, plus a Viessmann buffer vessel and domestic hot water cylinder, are located in a small, converted plant room attached the farmhouse. Geothermal collectors had to be buried in hilly ground which ascended steeply over a distance of 200 metres from the farmhouse. The length of the pipes needed is determined by pipe diameter, pump performance, heat pump flow rate, and the type of ground collector.
The Vitocal 350-G has a highly-efficient Coefficient of Performance (CoP) of 5.0, meaning it generates more than five times the usable heat from one kilowatt hour of electricity. The result is a consistently and comfortably warm farmhouse; zero carbon emissions, because what little electricity the heat pump needs is provided by solar panels and batteries; and financial savings, compared to the previous oil-fired boiler, of £4,000 to £5,000 per year – and this was before the invasion of Ukraine sent oil prices skyrocketing. Which means the Vitocal 350-G has provided everything Dot McCarthy hoped for - environmentally and economically.