Solarna toplana sa sezonskim spremnicima toplinske energije u gradu Zagrebu

Solar heating plants exist for many years, but they were not used for big district heating systems until lately. Today, implementation of this technology is more often than ever for big heating systems, especially in Denmark. Knowing that solar irradiation is more intense during the summer, and that heating demand is greater during the winter, it is necessary to store the heat in the seasonal storage. Near Zagreb, there is a solar heating plant project just being built, in Graz, where climate conditions are similar to the ones in Zagreb. Croatia has more solar insulation that Denmark and or Austria, so there is definitely potential for implementation of solar heating plants in Croatian energy system. Currently there is only one solar heating plant used in bigger heating system, and it is located in town called Vukovar. In first part of this paper there were proposed 2 solar heating plants that would cover approximately half of the heating demand in current district heating system of Zagreb. Also, there were proposed areas and locations to fit solar collector fields and seasonal heat storages. There are shown hourly shares of heat, defined by the energy source and amount of heat being accumulated in heat storages. Cost analysis was made to determine the investment cost for solar plants and to determine levelized cost of heat (LCOH). In comparison, it was analyzed what would be the cost of energy produced in gas combined heat and power (CHP) plants, that are being used mostly today for heat production in Zagreb and the rest of Croatia. In the second part, most populated areas around Zagreb were connected by the heating network. It was shown for which areas it is feasible to connect them to the existing district heating system and what would be the cost per unit of served heat. Routes for connection lines are also proposed. For the new, expanded heating system, there were created two scenarios – first one with proposed one big solar heating plant, that would cover all the demand from the mentioned system and the second scenario with many smaller solar heating plants that would be positioned in different locations around Zagreb. For the plants, there are proposed locations with needed area and also connecting lines to the rest of the system.