Most solar thermal systems have a separate antifreeze filled loop for protection against freezing and require a new tank
fitted with a heat exchanger. When retrofitting, a perfectly good tank (usually copper) needs to be replaced. Soltropy Ltd
has developed an innovative solution that allows a domestic water supply to be heated directly without the secondary fluid
cycle. This increases the efficiency of the system and reduces capital and installation costs by allowing the system to
freeze but cause no damage; this is achieved by incorporating a compressible tube within an outer copper pipe. When the
system freezes the compressible tube takes up the expansion due to the ice and prevents pressure build up. As part of this
project the thermal connection between the header pipe and the heat pipe in the evacuated tube will modularised, allowing
a standard copper pipe to be used as the header with single units clamping over the pipe. This will reduce costs further as
the modular connector can be mass produced. In addition the control system will be optimised, simplified and modularised.
Tests at Heriot-Watt University to date have shown that the Soltropy system behaves differently from an "old style" system
and therefore requires different control strategies.

Potential Impact:
One of the primary beneficiaries of the project will be Soltropy Limited. This project has the potential to significantly impact
the profitability of Soltropy Ltd.; by developing a low cost solar thermal system the commercial market for their product and
services will increase substantially. The project will up-skill one Research Associate and give them experience in technoeconomic
modelling, solar thermal devices and control electronics. This will directly increase the RAs employability directly
following the completion of the project.
The proposed project will reduce the cost of solar thermal technology for domestic and small industrial consumers. Since
approximately 70 per cent of energy used in UK households is for space or water heating, the benefits of reducing the cost
of heat from renewable energy sources therefore will significantly reduce fuel poverty and carbon dioxide emissions and
help to mitigate climate change.
The renewable energy technology industry is currently heavily reliant on government incentive schemes such as the RHI
(Renewable Heat Incentive) and more broadly the solar photovoltaic industry benefits from the Feed-In Tariff (FIT).
Reducing the cost of converting energy from renewable sources will make these technologies competitive in the energy
marketplace. Therefore the benefit to society in financial terms will be significant as incentives can be reduced and
eventually eliminated.
Finally, there is significant potential to impact future research in this area. This is discussed in greater detail in the
"Academic Beneficiaries" section, where a new approach to the research is proposed. This project will employ a Techno-
Economic approach to the design of a renewable energy conversion device and demonstrate how the cost of renewable
energy can be reduced. The potential impact of this project to have a legacy for research and development of renewable
energy technology could be profound and long-lasting.