scholarly journals Outdoor Air Temperature Measurement: A Semi-Empirical Model to Characterize Shelter Performance

Climate ◽  
2019 ◽  
Vol 7 (2) ◽  
pp. 26
Author(s):  
Jérémy Bernard ◽  
Pascal Kéravec ◽  
Benjamin Morille ◽  
Erwan Bocher ◽  
Marjorie Musy ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Response Time ◽  
Air Temperature ◽  
Empirical Model ◽  
Regression Coefficient ◽  
Radiation Sensitivity ◽  
Temperature Sensors ◽  
Outdoor Air ◽  
The One ◽  
Semi Empirical

Shelters used to protect air temperature sensors from solar radiation induce a measurement error. This work presents a semi-empirical model based on meteorological variables to evaluate this error. The model equation is based on the analytical solution of a simplified energy balance performed on a naturally ventilated shelter. Two main physical error causes are identified from this equation: one is due to the shelter response time and the other is due to its solar radiation sensitivity. A shelter intercomparison measurement campaign performed by the World Meteorological Organization (WMO) is used to perform a non-linear regression of the model coefficients. The regression coefficient values obtained for each shelter are found to be consistent with their expected physical behavior. They are then used to simply classify shelters according to their response time and radiation sensitivity characteristics. Finally, the ability of the model to estimate the temperature error within a given shelter is assessed and compared to the one of two existing models (proposed by Cheng and by Nakamura). For low-response-time shelters, our results reduce the root mean square error by about 15% (0.07 K) on average when compared with other compensation schemes.

scholarly journals Métodos baseados em temperatura do ar para estimativa de radiação solar incidente diária no Estado do Rio de Janeiro

2020 ◽  
Vol 12 (6) ◽  
pp. 2325
Author(s):  
Desirre Santos Mazzarella ◽  
Henderson Silva Wanderley ◽  
José Francisco de Oliveira Júnior ◽  
Givanildo Gois ◽  
Gustavo Bastos Lyra
Keyword(s):  
Solar Radiation ◽  
Air Temperature ◽  
Rio De Janeiro ◽  
Input Parameter ◽  
Simulation Models ◽  
Empirical Methods ◽  
Thermal Amplitude ◽  
Using Data ◽  
The One ◽  
Atmospheric Transmissivity

A radiação solar global (Rs) é um parâmetro de entrada necessária para estimativa da evapotranspiração e em modelos de crescimento, desenvolvimento e simulação do rendimento das culturas. Em locais com ausência de dados de Rs, podem ser utilizados métodos empíricos em função dos extremos de temperatura do ar para sua estimativa. No estado do Rio de Janeiro, estudos sobre Rs com base em métodos empíricos são escassos. Portanto, o objetivo foi estimar Rs diária com base no método de Hargreaves-Samani (HS) por meio de dados da amplitude térmica diária de 11 estações meteorológicas automáticas na escala bianual (2013-2014). O desempenho do método HS com o coeficiente proposto por Hargreaves (1994) e calibrado por Allen (1995) foi avaliado com indicadores estatísticos. O coeficiente R² variou entre 0,30 a 0,85, seguido do índice d entre 0,58 a 0,95 e do índice c entre 0,32 a 0,87, classificados como “Péssimo” a “Ótimo”. O erro absoluto variou de -6,23 a 7,09 MJ m-2 d-1 e o RQME 2,98 entre 8,69 MJ m-2 d-1. Baseado nos resultados o coeficiente proposto por Hargreaves (1994) resulta em estimativas precisas em comparação ao calibrado por Allen (1995), com ressalva das estações costeiras.  Methods based on air temperature to estimate daily incident solar radiation in Rio de Janeiro State A B S T R A C TGlobal solar radiation (Rs) is a necessary input parameter for estimating evapotranspiration and in crop growth, development and simulation models. In places with no data of Rs, empirical methods may be used as a function of the extremes of air temperature for their estimation. In the state of Rio de Janeiro, studies on Rs based on empirical methods are scarce. Therefore, the objective was to estimate daily Rs based on the Hargreaves-Samani (HS) method using data from the daily thermal amplitude of 11 automatic meteorological stations on a biannual scale (2013-2014). The performance of the HS method with the coefficient proposed by Hargreaves (1994) and calibrated by Allen (1995) was evaluated with statistical indicators. The R² coefficient ranged from 0.3 to 0.85, followed by the d index between 0.58 to 0.95 and the c index between 0.32 to 0.87, classified as "Poor" to "Great." The médium erro ranged from -6.23 to 7.09 MJ m-2 d-1 and RMSE 2.98 to 8.69 MJ m-2 d-1. Based on the results, the coefficient proposed by Hargreaves (1994) results in more accurate estimates compared to the one calibrated by Allen (1995), with the exception of the coastal stations.Keywords: meteorological parameters, atmospheric transmissivity, thermal amplitude. 

scholarly journals Errors of Naturally Ventilated Air Temperature Measurements in a Spatial Observation Network

2008 ◽  
Vol 25 (11) ◽  
pp. 2145-2151 ◽  
Author(s):  
Matthias Mauder ◽  
R. L. Desjardins ◽  
Zhiling Gao ◽  
Ronald van Haarlem
Keyword(s):  
Solar Radiation ◽  
Air Temperature ◽  
Agricultural Land ◽  
Sensible Heat Flux ◽  
Temperature Sensors ◽  
Radiative Heating ◽  
Temperature Measurements ◽  
Observation Network ◽  
Temporal Averaging ◽  
Radiation Shields

Abstract A spatial network of 25 air temperature sensors was deployed over an area of 3.5 km × 3.5 km of agricultural land, aiming to calculate the sensible heat flux by spatial averaging instead of temporal averaging. Since temperature sensors in naturally ventilated solar radiation shields were used for these measurements, a correction for radiative heating had to be applied. In this study, the approach of Anderson and Baumgartner was adapted to the cube-shaped HOBO solar radiation shields. This semiempirical correction depends on the shield’s area normal to the sun in addition to solar radiation and wind speed. The required correction coefficients, which can be universally applied for this type of shield, were obtained through comparison with fan-aspirated temperature measurements at one site. The root-mean-square error of the HOBO temperature measurements was reduced from 0.49° to 0.15°C after applying this radiation correction.

scholarly journals Solar radiation exposure of shielded air temperature sensors and measurement error evaluation in an urban environment: a preliminary study in Florence, Italy

2009 ◽  
Vol 3 (1) ◽  
pp. 9-12 ◽  
Author(s):  
M. Petralli ◽  
L. Massetti ◽  
S. Orlandini
Keyword(s):  
Solar Radiation ◽  
Radiation Exposure ◽  
Air Temperature ◽  
Urban Areas ◽  
Thermal Conditions ◽  
Surface Characteristics ◽  
Temperature Sensors ◽  
Island Effect ◽  
Synoptic Conditions ◽  
Solar Radiation Exposure

Abstract. Particularly in summer, thermal conditions in urban areas are influenced by solar radiation and human health can be strongly affected by the higher temperature regime increased by the Urban Heat Island effect (UHI). Many studies have been carried out to estimate the temperature distribution in urban areas and some of these use or are based on data collected by meteorological instruments placed within the cities. At microscale, temperature collected by sensors can be influenced by the underlying surface characteristics and the closeness to warm surfaces. The aim of this study is to investigate how different exposure to solar radiation can affect air temperature measurement in streets and gardens. The study was carried out on two different areas in Florence during summer 2007. Shielded air temperature sensors were placed in a street of a high density built-up area and in a green area. Each area was monitored by two sensors, sited in different solar radiation exposure: one in a sunny area and the other in a shaded one. A preliminary data analysis showed a difference in every site between the air temperature values collected by the two sensors especially from the morning to the afternoon. The relationship between air temperature differences and synoptic meteorological conditions were also analyzed. In conclusion, the solar radiation exposure of a monitoring station is an important parameter that must be considered both during the instruments siting and the analysis of data collected by sensors previously placed. The result of this study shows that during particular synoptic conditions, data collected by the two sensors of the same area can be different.

scholarly journals A New Method to Determine the Annual Energy Output of Liquid-Based Solar Collectors

Energies ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 4586 ◽  
Author(s):  
Zukowski ◽  
Radzajewska
Keyword(s):  
Solar Radiation ◽  
Air Temperature ◽  
Hot Water ◽  
Energy Output ◽  
Total Solar Radiation ◽  
Energy Yield ◽  
Solar Collectors ◽  
Solar Panels ◽  
Outdoor Air ◽  
Solar Thermal Collectors

One of the most effective ways to reduce greenhouse gas emissions is the widespread use of solar panels. A new approach to estimating the annual energy output ESC of liquid-based solar thermal collectors is presented in this paper. The main parameters of the surrounding environment that affect the energy yield from solar water heating (SWH) systems are total solar radiation ES and outdoor air temperature θO. Here, two functions are developed that allow the specification of the ESC value based on these two previously determined factors. The article presents the subsequent stages that led to the development of this method. In the first step, the computer model of a solar domestic hot water (SDHW) system was built in the EnergyPlus environment. An object of the modeling procedure was the real solar installation located at Bialystok University of Technology. The database containing the annual energy output of the solar collectors, total solar radiation, and outdoor air temperature was developed based on the results of simulations made for 24 Polish cities. Then, the multiple regression method (implemented in Statistica v.13.1) was used to correlate these variables. Two contour graphs were also developed to determine the energy yield from solar collectors.

scholarly journals Empirical Models for Estimating Global Solar Radiation over the Ashanti Region of Ghana

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Emmanuel Quansah ◽  
Leonard K. Amekudzi ◽  
Kwasi Preko ◽  
Jeffrey Aryee ◽  
Osei R. Boakye ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Air Temperature ◽  
Empirical Model ◽  
Global Solar Radiation ◽  
Temperature Measurements ◽  
Coefficient Of Determination ◽  
Temperature Dependent ◽  
Tropical Regions ◽  
Ashanti Region ◽  
Sunshine Hours

The performances of both sunshine and air temperature dependent models for the estimation of global solar radiation (GSR) over Ghana and other tropical regions were evaluated and a comparison assessment of the models was carried out using measured GSR at Owabi (6°45′0′′N, 1°43′0′′W) in the Ashanti region of Ghana. Furthermore, an empirical model which also uses sunshine hours and air temperature measurements from the study site and its environs was proposed. The results showed that all the models could predict very well the pattern of the measured monthly daily mean GSR for the entire period of the study. However, most of the selected models overestimated the measured GSR, except in April and November, where the empirical model using air temperature measurements underestimated the measured GSR. Nevertheless, a very good agreement was found between the measured radiations and the proposed models with a coefficient of determination within the range 0.88–0.96. The results revealed that the proposed models using sunshine hours and air temperature had the smallest values of MBE, MPE, and RMSE of −0.0102, 0.0585, and 0.0338 and −0.2973, 1.7075, and 0.9859, respectively.

scholarly journals Prediction of Tomato Yield on the Basis of Solar Radiation Before Anthesis under Warm Greenhouse Conditions

HortScience ◽  
2009 ◽  
Vol 44 (7) ◽  
pp. 1874-1878 ◽  
Author(s):  
Tadahisa Higashide
Keyword(s):  
Solar Radiation ◽  
Solanum Lycopersicum ◽  
Air Temperature ◽  
Fruit Weight ◽  
Data Sets ◽  
Fruit Number ◽  
Tomato Yield ◽  
Before And After ◽  
Greenhouse Cultivation ◽  
The One

Effects of solar radiation and temperature in different periods before and after anthesis on yield of tomato (Solanum lycopersicum) in summer greenhouse cultivation were investigated. Fluctuations in yield were caused mainly by the variation in fruit number rather than fruit weight. The number of harvested fruit and the yield of plants grown in summer and fall were significantly and positively correlated with solar radiation during the days before anthesis. Although the fruit number and yield were also significantly correlated with air temperature before anthesis, the correlations were weaker than the correlations with solar radiation. There was no significant correlation between the air temperature in the periods encompassing 3 weeks before harvesting and the fruit number and yield. Therefore, fluctuations in fruit number and yield could be predicted by a model based on the solar radiation from 10 to 4 days before anthesis. Validation based on data sets independent of the one used to develop this model showed good correlations between observed and predicted results for plants grown in summer and fall. Thus, solar radiation before anthesis was one of the important factors in prediction of tomato yield under warm greenhouse conditions.

scholarly journals A semi-empirical model for estimating surface solar radiation from satellite data

2013 ◽  
Author(s):  
Serm Janjai ◽  
Somjet Pattarapanitchai ◽  
Rungrat Wattan ◽  
Itsara Masiri ◽  
Sumaman Buntoung ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Satellite Data ◽  
Empirical Model ◽  
Surface Solar Radiation ◽  
Semi Empirical

Simulation of the internal temperature in the Passol Laboratory, University of Debrecen

2012 ◽  
Vol 3 (1) ◽  
pp. 63-73 ◽  
Author(s):  
I. Csáky ◽  
F. Kalmár
Keyword(s):  
Temperature Variation ◽  
Air Temperature ◽  
Indoor Air ◽  
Storage Capacity ◽  
Building Structures ◽  
Internal Temperature ◽  
The One ◽  
Heavy Structure ◽  
East West ◽  
Made In

Abstract Nowadays the facades of newly built buildings have significant glazed surfaces. The solar gains in these buildings can produce discomfort caused by direct solar radiation on the one hand and by the higher indoor air temperature on the other hand. The amplitude of the indoor air temperature variation depends on the glazed area, orientation of the facade and heat storage capacity of the building. This paper presents the results of a simulation, which were made in the Passol Laboratory of University of Debrecen in order to define the internal temperature variation. The simulation proved that the highest amplitudes of the internal temperature are obtained for East orientation of the facade. The upper acceptable limit of the internal air temperature is exceeded for each analyzed orientation: North, South, East, West. Comparing different building structures, according to the obtained results, in case of the heavy structure more cooling hours are obtained, but the energy consumption for cooling is lower.

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