Prefeasibility study on cool storage systems

From the overview undertaken it was realized that cool storage systems have already been commercialized in the USA and in few countries in Europe. In the USA they were, however, mainly applied to air conditioning systems. Cool was stored in the form of both sensible and latent heat. In Europe the trend was to use cool storage in connection with commercial refrigerating cycles which were based mainly on storing the cool. Cool storage in Finland has considerable potential particularly for continuous operation cycles which operate with smaller refrigerating units thus implying less investment costs for both the refrigerating and cool storing systems. This is, in addition to the savings, due to producing part of day-time energy with night tariff. On the other hand, intermittent operation in which all the cool is produced during the night and used in the day-time is not cost effective in Finland. The third alternative studied was to provide existing refrigerating units with a cool storage system. This alternative was cost-effective only if the cool was stored in the form of latent heat in suitable eutectic solutions. Technically it is possible to store nature cool and to use it in improving the performance of the refrigerating cycle, in resulting substantial energy savings. Several systems and solutions exist that benefit from natural outdoor cool. A comprehensive cost-effectiveness study should, however, be undertaken on these systems and solutions. Among the points which need further development and investigation are the combined storage of heat and cool, cool storage systems for the domestic sector and the use of optimal storing media and reservoirs for a given cooling temperature.