Novel advances pump new life into solar thermal heating An EU-funded project demonstrated a new generation of combined heat pump and solar components that can greatly improve energy efficiency of homes, cutting energy bills more than 25 %. Energy © Michel Haller Solar thermal collectors are rapidly gaining ground in many European countries as a means to sustainably provide space heating and domestic hot water for buildings. However, future success requires compactly combining solar energy storage with heat pumps that provide heat all year round using ground source or ambient air in addition to the Sun. The EU-funded project MACSHEEP (New materials and control for a next generation of compact combined solar and heat pump systems with boosted energetic and exergetic performance) developed the requisite compact but combined renewable energy systems that enable superior performance at competitive prices. Some measures to boost performance and cost effectiveness were the use of heat pump and storage optimisation as well as low-cost materials. Scientists also developed information and communications technology for intelligent control of storage management, online monitoring and fault detection to enhance energetic performance and reliability. Researchers developed four heat pumps combined with solar thermal systems that use heat from the ground, air and Sun. The solutions suit houses that have low space heating demands and low network supply temperatures as well as refurbished houses with higher supply temperatures. Heat pumps have been designed for different target heat loads and different system concepts. Some of them use the newest generation of speed-controlled scroll compressors, an economiser cycle and a desuperheater for domestic hot water preparation. New breakthroughs in the development of solar collectors include selective paints for an unglazed metal collector and a new design of a glazed photovoltaic-thermal collector with polysiloxane gel as an encapsulation compound for the photovoltaic cells. This hybrid collector provides both heat and electricity simultaneously with the ground-source heat pump. The heat can be used directly for storage tank charging, and the electricity can be used to power both the solar heat pump system and an electric heater that charges the upper part of the storage system. The combined solar and heat pump systems will be an important part of the energy mix, supplying a large fraction of renewable energy to buildings. MACSHEEP mainly targeted single-family homes that account for a large part of the EU's primary energy consumption and that often have much room for energy efficiency gains. Keywords Solar thermal, heat pump, energy efficiency, space heating, hot water, MACSHEEP
