The SWS-HEATING project will develop an innovative seasonal thermal energy storage (STES) unit with a novel storage material and creative configuration, i.e. a sorbent material embedded in a compact multi-modular sorption STES unit. This will allow to store and shift the harvested solar energy available abundantly during the summer to the less sunny and colder winter period thus covering a large fraction of heating and domestic hot water demand in buildings. The targeted benefit of this next generation solar heating technology is to reach and overcome a solar fraction of 60% in central/north Europe, reaching 80% in the sunnier south of Europe, with a compact and high-performing STES system at low cost, realising solar active houses throughout EU.
The SWS-heating system is based on a multi-modular sorption seasonal thermal energy storage (STES) unit, using novel sorbent materials of Selective Water Sorbents (SWS) family characterised by superior heat storage density compared to the state of the art, making it possible to drastically decrease the storage volume with negligible thermal losses. These materials are employed in a sorption module with dedicated heat exchangers. Solar heat is provided to the storage modules by high efficiency evacuated tube solar thermal collectors to supply domestic hot water (DHW) up to 60 °C. Higher temperature solar heat (at temperatures above 90 °C) will be used mainly to charge the seasonal storage unit during summer, allowing to store the heat for several months, bridging the summer-winter period. This way a maximised use of solar input heat throughout the year is ensured.
During winter, the stored heat will preferentially be used for space heating, and a backup heater will operate only when all stored heat has been fully discharged to cover the heat demand.
The adsorber/desorber HEX with the SWS-material embedded inside is the core component of the SWS-STES sorption module. Until now, HEXs used in adsorption machines have been developed mainly for other applications (e.g. automobile, air-conditioning). Dedicated plate HEXs will be developed in order to outperform the standard finned flat tube HEX, widely employed in adsorption appliances so far. The most effective configuration will be developed in terms of achievable specific heating power, coefficient of Performance (COP) value, dynamic behaviour and maximised lifetime. The overall aim is to reach high TES density, as well as to improve heat and mass transfer effectiveness leading to high power density (~90 kW/m3) as well as reduced component volume and cost.
The evaporator and condenser HEXs are the other two key components of the SWS-STES configuration, having a crucial role for reaching high performance and decrease its volume. As for the adsorber, the use of plate HEXs for these components is anticipated to enhance the performance of adsorption heat utilization appliances.
Project homepage: www.swsheating.eu