A technique for Quantifying the Reduction of Solar Radiation due to Cloud and Tree Cover

Loveday, Jane; Loveday, Grant; Byrne, Josh; Ong, Boon-lay; Newman, Peter

doi:10.1016/j.proeng.2017.04.199

Cited by 3 publications

(5 citation statements)

References 13 publications

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“…The temperature difference measured between a matt-black-painted iButton and a glossy-whitepainted iButton (TB − TW), is thus projected to be consistent over the solar spectrum. This was observed in a study by [41], where TB − TW was found to have a linear relationship with the SR measured using a pyranometer. A reference pair of iButtons were used facing upwards to measure the incident SR.…”

Section: Instrumentationsupporting

confidence: 65%

“…DiR is the ratio of the reflected radiations based on the incident radiant energy to the iButtons being linearly proportional to T B − T W , [41]. This can also be written as a ratio of albedos (Equation (2)):…”

Section: Albedo Found Using Wpp As a Reference-approachmentioning

confidence: 99%

“…Before a comparison between the temperatures of the reference and the LE iButton pairs could be made, the temperature data needed to be converted into a radiation flux or radiant exitance. This is because the calibration of reference iButtons undertaken by [41] found there was a non-zero intercept in the linear regression. The SR from the weather station from 09:10 to 15:40 on 21 January 2019 was used to calibrate the reference iButtons using a linear regression, giving two coefficients equivalent to the slope and intercept of the data.…”

Section: Albedo Found Using Direct Incident Solar Radiation As a Refementioning

confidence: 99%

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Modified iButtons: A Low-Cost Instrument to Measure the Albedo of Landscape Elements

Loveday

Loveday²,

Byrne

et al. 2019

Sustainability

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Urban infill can lead to increased urban air and surface temperatures. Landscape elements (LEs) which can maintain cooler surface temperatures also reduce night-time re-emission of heat; however, reflected solar radiation (albedo) from these LEs during the day potentially increases heat loads on nearby objects, pedestrians or buildings. Albedo is traditionally measured using two pyranometers, however their expense can be prohibitive for researchers and landscape professionals. A low cost albedometer was developed consisting of a pair of black- and white-painted temperature sensors (Thermochron® iButtons). The albedos of 14 LEs typically found in suburban landscapes in Perth, Western Australia, were measured. Three approaches were tested: The first two used white-painted polystyrene (WPP) as a reference (one taking view factors into account, and one ignoring the albedo of the background material), whilst the third approach used upwards-facing iButtons as a reference, similar to conventional pyranometer methods. The WPP approaches controlled for weather effects, providing a consistent albedo over a longer daytime period than recommended by the standard ASTM-E1918-16. Measured albedos were similar to literature values. This instrument could be used as an alternative to more expensive pyranometers and could assist landscape professionals to design for, and manage, urban heat.

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Section: Instrumentationsupporting

confidence: 65%

Section: Albedo Found Using Wpp As a Reference-approachmentioning

confidence: 99%

Section: Albedo Found Using Direct Incident Solar Radiation As a Refementioning

confidence: 99%

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Modified iButtons: A Low-Cost Instrument to Measure the Albedo of Landscape Elements

Loveday

Loveday²,

Byrne

et al. 2019

Sustainability

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show abstract

“…Small wireless temperature sensors called Themochron iButtons (Maxim Integrated, San Jose, CA, USA) [42], capable of logging data over long time periods, were used as low-cost radiometers by painting one surface with matt black paint [45]. These painted sensors measure 17 mm in diameter and are 6 mm high (Figure 3a).…”

Section: Study Design Phase 1 (Small Les)mentioning

confidence: 99%

“…It will also respond to convected heat from the LE, although this depends on its proximity to the LE and the strength of the wind currents. Each LE had a black painted iButton mounted in a polystyrene block (described in [45]), suspended 0.2 m above it, protruding 0.15 m towards the centre of the LE from the middle of one edge of the LE (Figure 3b). The top side of the polystyrene was covered in aluminium foil to reduce solar heat gain to the iButton.…”

Section: Study Design Phase 1 (Small Les)mentioning

confidence: 99%

Radiosity from Individual Urban Landscape Elements Measured Using a Modified Low-Cost Temperature Sensor

Loveday

Loveday²,

Byrne

et al. 2020

Urban Science

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Loss of green space in our suburban environment is contributing to increased urban heat. The material properties of surface treatments or landscape elements (LEs) are a determining factor in the amount, timing, and type of radiation present in the local environment. Landscape designers can use this information to better design for urban heat management, as emitted and reflected radiation (radiosity) from LEs can affect pedestrians via heat stress and glare and affect energy usage in buildings and houses if the landscape sky view factor is low. Low-cost black painted iButton temperature sensors were successfully used as radiometers to concurrently measure the daytime radiosity from 19 LEs samples located on an oval in the warm temperate climate of Perth, (Australia). Normalisation against gloss white paint on polystyrene removed the effect of varying weather conditions. Each LE had the same normalised average radiosity (DRav) between seasons (within ±5%), meaning the relative radiosity of new LEs can be measured on any day. White and lighter coloured LEs had the highest DRav and would have the most detrimental effect on nearby objects. Plants and moist LEs had the least DRav and would be most beneficial for managing local daytime urban heat. Measuring relative radiosity with iButtons presents a new way to examine the effect of LEs on the urban environment.

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A spectrally-resolved method for evaluating the solar effect on user thermal comfort in the near-window zone

Wang

2021

Building and Environment

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A technique for Quantifying the Reduction of Solar Radiation due to Cloud and Tree Cover

Cited by 3 publications

References 13 publications

Modified iButtons: A Low-Cost Instrument to Measure the Albedo of Landscape Elements

Modified iButtons: A Low-Cost Instrument to Measure the Albedo of Landscape Elements

Radiosity from Individual Urban Landscape Elements Measured Using a Modified Low-Cost Temperature Sensor

A spectrally-resolved method for evaluating the solar effect on user thermal comfort in the near-window zone

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