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This numerical study evaluates and compares four different flexibility and storage options in building energy systems (batteries, fuel switch, water tanks, and thermal building mass) in terms of potential improvements in load scheduling and energy efficiency. Using a generic modern office building with concrete core conditioning as an example, two different supply concepts (one based on a heat pump, one based on a CHP unit) are considered. A novel hybrid control concept is applied which is designed to be compatible with state-of-the-art controllers implemented in the field. The results show that batteries are the most technically attractive options in terms of grid support, efficiency and ease of implementation. Fuel switch is comparably straightforward to implement, but provides significant benefits only for the considered CHP system. Water tanks with a capacity of about two full operation hours offer nearly the same flexibility as much larger tanks, but negatively influence the efficiency of heat pump systems. The thermal building mass can be used effectively and efficiently for thermal storage, particularly in the heating season, but this is technically challenging to realize. It is shown that current electricity prices do not offer sufficient variations to stimulate grid-supportive operation. [ABSTRACT FROM AUTHOR]

A new method for assessing the grid interaction of a building’s electricity consumption and generation is presented. It consists of the Grid Support Coefficients GSC abs and GSC rel . GSC abs “weights” the electricity consumption profile with a time-resolved reference quantity which expresses the availability of electricity in the public grid (here: stock electricity price, residual load, cumulative energy consumption or fraction of wind and PV in the electricity mix). GSC rel relates GSC abs to the worst and best achievable values on a scale of −100 to 100 in order to increase the comparability of the results. The new evaluation method is applied to analyze the electricity consumption and/or production of 52 different energy supply systems in buildings, where detailed monitoring data are available. These examples include twelve heat pumps or chillers in office buildings, 38 heat pumps in residential buildings and two combined heat and power units (CHP) in multi-family buildings, all located in Germany. The in-depth analysis shows that the analyzed present-day buildings predominantly consume electricity at times with a low or average electricity availability. Optimal scheduling of all heat pumps could flatten the residual load significantly. In order to achieve this, thermal storages several times larger than the ones currently installed would be required. [ABSTRACT FROM AUTHOR]