Lake House Hotel Utilises Solar and Ground Source Heating

The Lake House Hotel has no reservations about Vaillant renewable ground source energy solutions.

Solar panels and a ground source heat pump from Vaillant have been installed in one of the UK’s most innovative heating projects at the luxurious Lake House boutique hotel, near Windermere, recently featured on ITV’s The Lakes.

Drawing heat from the natural Knipe Tarn, a 10kW Vaillant geoTHERM heat pump is believed to be the first to be installed in the UK without first draining the lake. It now provides underfloor heating for the hotel, while five Vaillant auroTHERM exclusive vacuum tube solar panels preheat water which is fed into a bespoke tank in tank domestic hot water system, reducing energy bills further.

Using Knipe Tarn to provide a heat source was the brainchild of architect Ben Cunliffe, whose family owns and runs The Lake House, but it was left to Mick Lloyd, Director of Lancaster-based installer Wheildons, and renewables experts from manufacturer Vaillant to design a heating system and devise a scheme for the installation.

Mick Lloyd, Director of Wheildons, said, “We worked very closely with Vaillant throughout this project as it presented some interesting challenges. Combining our knowledge we came up with some very satisfactory solutions. Lakes are a good source of energy for heat pumps, in my opinion better than a horizontal layout and almost as good as a borehole. Knipe Tarn is around 5m deep, which is a good depth for a lake heat pump application. The installation has successfully provided heat during its first winter and has provided the cosy environment needed for the guests of this luxury hotel.”

Normally when heat pumps are installed in lakes, the lake is either purpose built for the installation or drained to allow the heat pump collectors to be secured to the bottom of the lake, then filled; however, at Knipe it wasn’t possible to drain the lake. The Lake House uses water from Knipe Tarn for bathing and drinking water, first cleaning and processing it through a filtration plant. This meant that installation of the collectors had to be achieved without churning up the water or disturbing the lake bed. Using divers was not an option either due to the risks of contamination and churn.

Vaillant’s Mark Barson and Wheildons’s Mick Lloyd worked together to find a solution. They devised a galvanised steel framework in four parts; 200m of collector was coiled and fastened onto each, then the framework was floated out to the chosen location in the lake, with weights tied to each section to make it sink. The floatation devices were then cut loose to allow the framework with the collection coils to settle onto the bottom of the lake in the desired location.

Two lengths of 50m were left free on two of the collector frames to bring ashore to connect with a 4 part manifold which was installed underground on the lake shore, accessed via a manhole. Two larger pipes then lead from the manifold up to the house, buried in a specially constructed trench under the front lawn, and are connected to the Vaillant 10kW geoTHERM heat pump, which is installed in the underground storage room and laundry beneath the main house. This system gives a COP of approximately 4:1 and provides underfloor heating for all the hotel’s luxury suites and common areas.

Two lengths of 50m were left free on two of the collector frames to bring ashore to connect with a 4 part manifold which was installed underground on the lake shore, accessed via a manhole. Two larger pipes then lead from the manifold up to the house, buried in a specially constructed trench under the front lawn, and are connected to the Vaillant 10kW geoTHERM heat pump, which is installed in the underground storage room and laundry beneath the main house. This system gives a COP of approximately 4:1 and provides underfloor heating for all the hotel’s luxury suites and common areas.

Domestic hot water for the Lake House is provided by a bespoke tank in tank installation designed by Wheildons for the purpose. This also heats a small network of towel rails in all the en suites. The cold water that feeds into this is pre-heated first by a Vaillant solar system. Five Vaillant auroTHERM exclusive vacuum tube solar panels, installed on the roof by Wheildons, preheat water and feed it into a 350L store.

The incoming water to the tank in tank system can often be as hot as 40ºC, making a significant contribution towards reducing running costs.