Assessing solar energy accessibility at high latitudes: A systematic review of urban spatial domains, metrics, and parameters.

This paper presents a systematic literature review of solar energy studies conducted in Nordic built environments to provide an overview of the current status of the research, identify the most common metrics and parameters at high latitudes, and identify research gaps. 55 publications are included in the review and categorized according to three main urban spatial domains: (i) outdoor, (ii) envelope, and (iii) indoor. In addition, a category for publications investigating more than one spatial domain (multi-domain) is included. The first part of the paper presents a publication analysis of keywords, history and methods, channels, citations, geographical distribution, and spatial domain coverage. In the second part, the main findings for each urban spatial domain are presented and discussed. The results show that the majority of the studies applied numerical methods in their workflow and the envelope is the most researched spatial domain, with studies focusing either on the potential exploitation of solar energy through active solar systems, or the prediction of indoor daylight conditions by using the façade as a proxy for the indoor domain. Among the main findings, urban density, building morphology, and orientation are the most utilized parameters, while solar irradiation and direct sunlight are the most common metrics. This review paper reveals significant research gaps in the field of solar accessibility in high-latitude Nordic built environments: (i) numerical studies that simultaneously address and interlink all three urban spatial domains are missing; (ii) deeper investigation of the outdoor domain is needed.