Project ALIGHT will undertake a feasibility study of the development of new, innovative technologies for a range of small energy systems with much greater commercial and carbon-saving potential than can be achieved with incumbent technologies. The systems are: micro-turbine generators (<100 kWe), waste heat to power systems and heat pumps using supercritical CO2 (SCCO2) as the working fluid, and absorption coolers. They have many potentially very large markets: decentralised power, CHP and tri-generation; off-grid power systems such as generators for isolated mobile phone towers; bottoming power cycles for solid oxide fuel cells; heat pumps to replace gas boilers in domestic and commercial buildings; commercial and industrial cooling; cooling for refrigerated transport and electric vehicles, and many others. These systems share two crucial characteristics: they depend on two or more heat exchangers; and the size, weight, cost and low effectiveness of the heat exchanger technologies presently used severely limits their cost effectiveness and commercial viability in their potentially very large markets. The project focuses on the technical and financial feasibility of designing new, much smaller, lighter heat exchangers for these systems, enabled by metal Additive Manufacturing (AM) or 3-D printing technology, and integrating them into single AM builds Recent experience in designing and building AM heat exchangers for high value, low volume aerospace and F1 applications shows that 40-80% reductions in size and weight can be achieved. However, the systems' lower value, higher volume target markets need even small, lighter, cheaper and more effective heat exchangers. So the project's specific focus is on assessing new, innovative AM heat transfer surfaces and architectures to provide additional 40-60% size/weight improvements over the present state of the AM art.