High-efficiency heat pump
Initial high costs and a long payback period because of insufficient efficiency have previously limited use of heat pump technology. This problem was investigated by the 'Development of high efficiency Stirling heat pump' (EFFIHEAT)(opens in new window) project, which is designing ground-source heat pump (GHP) technology capable of dramatic energy savings. Widespread application of EFFIHEAT GHP technology can result in EUR 0.03 billion potential annual savings. The new cost-efficient geothermal heat pump technology was based on a novel Stirling engine design operating in inverse cycle with 25 % higher performance coefficient. Scientists developed a Stirling oscillating heat pump based on a free-swinging piston electrical machine. They optimised pistons, displacers and heat exchangers to maximise heat transfer and minimise leakage. The novelty of the design makes it a more reliable product than conventional ones, with less maintenance and a long lifespan. A thermo dynamical model was designed to receive feedback about the entire system dynamics. Researchers developed a dynamical operation control system — an innovative software–hardware kit — to control the overall performance of the electrical machine. To increase Stirling heat machine performance, a sandwich-type cylindrical and a woven wire mesh regenerator were developed, acting as internal heat exchangers. A novel composite high-performance material for regenerators based on polymer foils doped with ceramic nano- or micro-particles was produced. The EFFIHEAT heat pump prototype was integrated and tested. For evaluating the achieved results, a survey was carried out and a business case validation was conducted as well. Both revealed that the EFFIHEAT Stirling heat pump technology meets user expectations. The GHP developed should deliver major energy savings in buildings through improved energy conversion with more efficient technology. This will help meet EU targets for reducing energy consumption and carbon dioxide emissions.
