Techno-economic analysis of solar options for a block-heating system

Journal article, 2018

An innovative small solar district heating system with one central heating plant and four solar substations has been built in Vallda Heberg, Sweden, to supply a new housing area with passive houses. The target solar fraction was 40% and the total system design, including heat distribution in the buildings, was based on previous experience and aimed to be simple and cost-effective. The main aim of this study was to determine whether the system can be designed in a more effective manner by change of distribution system and load density. TRNSYS models were calibrated against measured data and then used to predict the energy performance. Results indicate that lower distribution heat losses can be obtained by change to a novel distribution concept with lower operating temperatures, while potentially reducing cost. Increases in heat density cause reduced distribution losses and boiler supplied heat demand, with only minor effects on solar system yield.