Circular economy plays a central role in cities on a strategical level. However, concrete circularity plans and actions remain rare. This paper examines how a city district could target circularity with transportation, energy and food solutions. The analysis is performed for an existing case district in a planning phase. The aim is to provide real concrete examples. Firstly, technological alternatives and their energy and carbon emissions are analyzed numerically. Secondly, service solutions for each technology are suggested. Thirdly, relevant regulations are framed.

In the analyzed district, high-level circulation of urban streams is unlikely to occur. Almost carbon-free transportation is possible, resulting in extensive increase in local electricity demand. Locally produced biogas would contribute about 20 % of the gas demand of the most advanced transportation scenario. None of the several energy production alternatives would lead to local energy self-sufficiency. Waste heat recovery from a data center and a wastewater treatment plant could supply 58 % of the heat demand. 6 % of the food consumed could be produced locally.

The paper highlights the importance of considering interlinkages between different streams and sectors, revealing the complexity of a circular city. The analysis demonstrates that circularity in this district is possible, but requires multidisciplinary analysis.

循环经济在战略层面上在城市中发挥着核心作用。但是，具体的循环计划和行动仍然很少。本文研究了市区如何以交通，能源和食品解决方案为目标的循环性。在计划阶段对现有案例区域执行分析。目的是提供真实的具体示例。首先，对替代技术及其能源和碳排放进行了数值分析。其次，针对每种技术提出了服务解决方案。第三，制定相关法规。

在所分析的区域中，不太可能发生城市河流的高水平环流。几乎无碳的运输是可能的，从而导致当地电力需求的大量增加。在最先进的运输方案中，本地生产的沼气将占天然气需求的20％左右。几种能源生产替代方案都不会导致当地能源自给自足。从数据中心和废水处理厂回收的余热可以满足58％的热量需求。消耗的食物的6％可在当地生产。

本文强调了考虑不同流域和部门之间的相互联系的重要性，揭示了圆形城市的复杂性。分析表明，该地区的循环性是可能的，但需要多学科分析。