Floating hotel draws energy for heating from harbour waters

Project Overview

Bristol has declared that it “wants to become the UK’s first city for sustainable energy, leading the way towards smart energy efficiency, affordable warmth and 100% renewables.” In recognition of its wide-ranging initiatives reflecting this aim, the city was nominated European Green Capital of the Year in 2015.

At the same time, in Bristol’s famous docks a Dutch barge was being converted into a floating hotel and its owner was determined to adopt an environmentally-friendly source of heating. This resulted in the installation of a new technology which was the first of its kind in the UK.

The Viessmann Solution

Kyle Blue is a 105-foot-long 1920’s barge moored in Princes Wharf, Bristol, close to the world’s first great luxury liner, the steamship S.S. Great Britain. After serving as a restaurant boat, Kyle Blue had been empty for many years when local businessman Martin Jefferies decided to convert it into a floating hotel with 30 beds, nine bedrooms, two large public areas, and a large kitchen.

The boat’s heating was previously provided via an oil-fuelled system from a diesel engine but the Harbour Master didn’t want oil in the wharf and Martin already had the idea of using a heat pump to extract warmth from the harbour water.

Meticulous research lead Martin, a former engineer, to conclude that Viessmann would be the best company to deliver his vision. When he contacted Viessmann specialist contractors Earth Source Energy, they confirmed that latent heat from the harbour water could be used to provide space heating and hot water to Kyle Blue.

This would be made possible by a submersible heat exchanger, never before installed in the UK, connected to a Viessmann Vitocal ground source heat pump. To confirm this was feasible, calculations were made for the harbour’s annual average water temperature, temperature depths, and current flows.

Mark Schofield, managing director of Earth Source Energy, remembers: “Knowing the heat source and flow rates for the harbour was key to fitting the right system. Viessmannn’s ready-made schematics and hydraulic diagrams gave us extra support. Viessmann is our brand of choice across all heating technologies because they provide the right product for the right system without compromise.”

When heat is required for Kyle Blue, a brine pump switches on the submerged collector system in the harbour so that it absorbs heat from the water. This is fed into the Vitocal 300-G ground source heat pump, whose scroll compressor upgrades it to high-grade heat for space-heating or hot water. Any excess heat not needed to meet demand is stored for use later, in a 750-litre Viessmann Vitocell 300 buffer vessel and two 300-litre Vitocell 300-B domestic hot water cylinders. To ensure hygiene standards, an anti-legionella cycle is performed by the system every day.

Sustainable, economical and quiet

Combining Viessmann’s heat pump with the first heat exchanger of its kind to be fitted in the UK has given both Kyle Blue’s owner and Bristol’s Harbour Master exactly what they wanted: oil-free, environmentally friendly technology capable of meeting the heating and hot water demands of a 30-bed hotel. This solution is also much quieter than the boat’s previous heating system and more economical to run.

Viessmann’s heat pump technology also has the advantage of being eligible for payments from the government’s Renewable Heat Incentive (RHI) scheme, and this is bringing in £4,000 per year. The combination of energy savings and RHI income will mean that the system will pay for itself within four years - and in the years afterwards it will continue to provide the boathotel’s guest rooms, public rooms and kitchen with space heating and hot water at virtually no cost and with zero emissions.