SlurryStore – Experimental and numerical investigations of ice slurry storages

• Forschungsstelle: BFE
• Projektnummer: SI/502063

Kurzbeschreibung (Englisch)

The increasing use of power electronics and the growth of decentralized power generation, storage systems and flexible loads require a further focus on impacts on the power grid and their assessment. For a techni-cally correct and cost-efficient operation of the distribution grids, it is of major importance to understand the influence of different grid variants and loading conditions on the grid stability and the power quality. Due to the complex correlations and the boundary conditions in terms of availa-bility and quality, considering changing topology states, it is difficult to optimise electricity grids economically. Therefore, measurements will be performed in various low voltage grids to analyse the effects on compli-ance with EN 50160 when systems are operated beyond the limits of current rules that grid operators apply when assessing connection appli-cations. The economic potential of different grid construction methods will be compared, and a generic monitoring concept will be developed.

Publikationen / Ergebnisse (Englisch)

Solar-ice systems are becoming popular in Switzerland. However, state-of-the-art solar-ice systems have some disadvantages such as a usually higher cost compared to Ground Source Heat Pumps (GSHP) if the same performance is desired. Therefore, research is still needed to bring robust solar-ice systems to the market with comparable cost and higher efficiency compared to GSHP solutions. A feasibility study carried out in the project Slurry-HP undertaken by SPF (Carbonell et al., 2017) has shown that solar-ice systems based on the ice slurry heat pump using the supercooling approach have a high potential for cost reduction, while having a high energetic efficiency, especially for ice storage volumes of at least 1m3 per MWh of yearly heating demand, which corresponds well to ice storage volumes used today for multi-family buildings. Moreover, an ice slurry storage would allow to use existing rooms of the building efficiently since any shape and room size could store slurries if properly distributed. The supercooling ice slurry method is a concept for ice slurry production that does not rely on moving parts. It is based on supercooling water with a heat exchanger, the so-called supercooler, which allows one to supercool a liquid to a metastable state. This liquid is then pumped to the crystallizer where it undergoes nucleation to form an ice slurry mixture that is stored in the ice slurry tank. An important variable here is the degree of supercooling, defined as the freezing temperature minus the supercooled liquid temperature. This concept allows one to completely eliminate the heat exchangers from the ice storage and it also eliminates the efficiency lost by an insulating ice layer growing on the cooled surface. The solar ice slurry system is expected to have an installation cost reduction of 10 % respect to traditional solar-ice systems with ice-on-coil heat
exchangers.

Zugehörige Dokumente

• Annual Report [PDF] 5'861 kB