Modeling Natural Light Availability in Skyscraper Farms

Michael Eaton,Timothy Shelford,Neil Mattson,Kale Harbick

doi:10.3390/agronomy11091684

Michael Eaton, Timothy Shelford + Show 2 more

Open Access

https://doi.org/10.3390/agronomy11091684

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Abstract

Lighting is a major component of energy consumption in controlled environment agriculture (CEA) operations. Skyscraper farms (multilevel production in buildings with transparent glazing) have been proposed as alternatives to greenhouse or plant factories (opaque warehouses) to increase space-use efficiency while accessing some natural light. However, there are no previous models on natural light availability and distribution in skyscraper farms. This study employed climate-based daylight modeling software and the Typical Meteorological Year (TMY) dataset to investigate the effects of building geometry and context shading on the availability and spatial distribution of natural light in skyscraper farms in Los Angeles (LA) and New York City (NYC). Electric energy consumption for supplemental lighting in 20-storey skyscraper farms to reach a daily light integral target was calculated using simulation results. Natural lighting in our baseline skyscraper farms without surrounding buildings provides 13% and 15% of the light required to meet a target of 17 mol·m−2·day−1. More elongated buildings may meet up to 27% of the lighting requirements with natural light. However, shading from surrounding buildings can reduce available natural light considerably; in the worst case, natural light only supplies 5% of the lighting requirements. Overall, skyscraper farms require between 4 to 11 times more input for lighting than greenhouses per crop canopy area in the same location. We conclude that the accessibility of natural light in skyscraper farms in dense urban settings provides little advantage over plant factories.

Highlights

Introduction and Literature ReviewThe growing global population has raised concerns over meeting food demand within a context of decreasing availability of agricultural land
Plant lighting is typically discussed in terms of photosynthetic photon flux density (PPFD) in units of μmol·s−1·m−2, which is the rate at which photons within the photosynthetically active radiation (PAR) band (400–700 nm) reach a unit area
In terms of photosynthetic light provided by the sun, the mean daily light integral (DLI) values on each level of the skyscraper farms in the skyscraper farm in a field (SIF) scenarios were significantly below the target level of 17 mol·m−2·day−1 (Table 1)

Summary

Introduction

The growing global population has raised concerns over meeting food demand within a context of decreasing availability of agricultural land This has sparked interest in alternatives to traditional agricultural production and supply chains. To provide high-nutrientdensity food for an increasingly urban population, controlled environment agriculture (CEA) is a frequently discussed strategy due to its high space-use efficiency and ability to be located near consumers, and the reliability of weather independent production [2]. Skyscraper farms have been proposed as alternatives to greenhouses and plant factories in an attempt to increase space-use efficiency while accessing some natural light as well as offsetting the environmental cost of transporting food into urban area [8,9]. The daily light integral (DLI) is the cumulative daily PAR in units of mol·m−2·day−1

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