Upgrade of ice storage system in congress centre

Abstract

Storage of various forms of energy is a relevant topic in last decades. The ability to store energy that is produced at a time when we have a surplus of a particular source and use it at a time when energy needs are greater is crucial. We can store energy as electricity or as thermal energy (heat and cold). In this paper, we will take a closer look at latent cold storage with ice bank technology. Ice bank technology exploits latent heat in the liquid-solid phase change of water. Of all the cold storage technologies available, ice storage is the most popular in recent decades due to its high latent heat, especially when available space is limited. Cold in ice banks is produced at night, when electricity is cheaper, and is used to cover cooling needs especially at peak hours during the day. In Slovenia, the technology of ice banks has already been applied several times. Among other buildings, this technology is also used in buildings such as the Opera and Ballet, the Crystal Palace, and the Congress centre Cankarjev dom. This Congress centre has a system with nine ice banks with a total nominal capacity of 405 kWh per ice bank, for its cooling needs. The transition to ice bank technology has allowed them to cut by 41 % the power of their refrigeration units, while saving money is achieved since ice is produced at night time with lower prices. The article presents the three phases of the system: Energy for cooling of a system without ice banks, a system with ice banks and saved energy with this technology and an analysis of the upgrade of this system with PV modules. The simulations were done with the Trnsys program. Indicative savings with the application of ice banks and additional upgrades with PV modules are presented. The payback periods are also analysed.