A project to install a renewable energy heating system in a Dorset tearoom is to become a showcase for a proposed large-scale district heating scheme.
The under-floor system being planned at Upton Country Park in Poole will extract heat from a nearby duck pond.
Partners in the project want to use it to promote plans for a district system using heat drawn from Poole Harbour.
Poole Tidal Energy Partnership will invite tenders for the tearoom, with work expected to start in November.
The partnership, which includes Borough of Poole, Transition Town Poole, Bournemouth University and others, has been exploring ways to use the harbour as a source of energy.
Director Paul Cooling said: "We felt that trying to dive straight into the harbour would bring a lot of challenges, not just about the technology but also for the various interests in the harbour.
"If we could do a small-scale project, it would help people understand what we are trying to do, understand how the technology works and build investor confidence."
While water-sourced district heating is used in Scandinavia, Mr Cooling said the only large-scale project he had heard of in the UK was that of Kingston Heights in Surrey, which draws warmth from the River Thames to heat an apartment and office complex.
Poole Tidal Energy Partnership is already looking ahead to identify sites around the harbour that could benefit from district heating. Planning applications and tender invitations are expected to be finalised in the next few weeks.
The tearoom system, which will use heat pump technology, is hoped to be up and running by January or February 2015.