scholarly journals Evaluating the Effect of Different Base Temperatures to Calculate Degree-Days

2020 ◽  
Vol 24 (2) ◽  
pp. 364-372
Author(s):  
Xabat Oregi ◽  
Carlos Jimenez-Bescos
Keyword(s):  
Energy Consumption ◽  
Energy Demand ◽  
The Other ◽  
Base Temperature ◽  
Main Aspect ◽  
Degree Days ◽  
Northern Spain ◽  
Building Simulations ◽  
San Sebastian ◽  
Thermostat Temperature

AbstractDegree-days are used as a forecasting tool to predict energy demand and for normalizing energy consumption to be able to compare between different properties across different years. The base temperature is the main aspect to accurately calculate degree-days. The aim of this study was to evaluate the effect of different base temperatures and their impact on the correlation between energy consumption and degree-days. The base temperature was selected as the standard 15 °C for the region, the balance temperature calculated with dynamic building simulations and the thermostat temperature setting as collected by questionnaires. The methodology followed is based on the analysis of 20 properties located in the cities of Bilbao, San Sebastian and Vitoria in northern Spain. The properties are a combination of flats and houses, from different construction periods, tenancies, occupancy and sizes. This study had highlighted the effect and impact of selecting different base temperatures for the calculation of degree-days and the correlation between energy consumption and degree-days. While the use of the balance temperature as base temperature could generate very good correlation, they were not so dissimilar from using the standard 15 °C base temperature to justify the amount of extra work required to generate the balance temperature. The use of the thermostat setting as an indication of the base temperature was not as reliable as the other base temperature methods in generating a good correlation to explain the energy consumption on the 20 properties investigated in this study.

The Impact of Data Granularity of Indoor Temperature Measurements on the Calculation of Degree Days

2021 ◽  
Vol 25 (1) ◽  
pp. 1305-1316
Author(s):  
Xue Mei ◽  
Carlos Jimenez-Bescos
Keyword(s):  
Energy Consumption ◽  
Energy Demand ◽  
The United States ◽  
Base Temperature ◽  
Degree Days ◽  
Indoor Temperature ◽  
Consumption Data ◽  
Data Points ◽  
Data Granularity ◽  
The Impact

Abstract Degree-days are to normalise energy consumption data and furthermore can generate forecasting predictions for energy demand being used to compare between different properties across different location and years. The base temperature is the main factor to consider the accuracy of degree days. The aim of this study was to evaluate the impact of data granularity to understand its effect on a correlation between energy consumption and Degree Days. Degree Days were calculated using the standard 18.3 °C base temperature as taking in the United States of America and compare the Degree Days calculations against the calculation based on hourly, daily and monthly data for base temperature. The methodology followed is based on the analysis of 23 houses located in Texas, Austin. The properties under study are from different construction periods and with a variety of total floor areas. This study had demonstrated the effect of the granularity of the data collected to generate Degree Days and its impact on the correlation between energy consumption and degree-days for different base temperatures. While the higher correlations are achieved using a monthly granularity, this approach is not recommended due to the small number of data points and a much more preferred approach that should be taken is a daily approach, which would generate a much more reliable correlation. In this study, higher correlation values were achieved when using the standard 18.3 °C base temperature for the Degree Days calculations, 70 % correlation in daily approach versus 56.67 % using indoor temperature, showing better results across the board against the use of indoor temperature at all granularity levels.

Energy demand estimates in large Russian cities and its biometeorological characteristics

2020 ◽  
Author(s):  
Iya Belova ◽  
Liudmila Krivenok ◽  
Sergy Dokukin
Keyword(s):  
Energy Consumption ◽  
Comparative Analysis ◽  
Wind Speed ◽  
Ambient Temperature ◽  
Energy Demand ◽  
Public Spaces ◽  
Base Temperature ◽  
Comfort Zone ◽  
Russian Science ◽  
Temperature Range

<p>To estimate the energy amount needed to heat indoor living and public spaces, the heating degree day (HDD) parameter is applied. This is the most common climatic indicator of energy consumption for the building heating, which is calculated for a certain period of the year by summing the absolute deviations of the average daily ambient temperature from the selected base temperature. However, human biometeorological sensitivity is based not only on the ambient temperature, but on a combination of temperature, humidity, and wind speed.</p><p>We have conducted a comparative analysis of the climatic and biometeorological characteristics of the regions including the largest Russian cities. For the effective ambient temperature range of 17.2 to 21.7⁰C (comfort zone), we have calculated changes in the comfort zone for Moscow, St. Petersburg, Krasnodar, Novosibirsk, and Vladivostok according to data from 1959 to the present. Despite all climate differences between regions with selected cities, allowance for wind speed leads to a decrease in the number of days with temperature within the comfort zone.</p><p>This study supported by Russian Science Foundation (project No 16-17-00114).</p>

A method to estimate the heating and cooling degree-days for different climatic zones of Saudi Arabia

2016 ◽  
Vol 38 (3) ◽  
pp. 327-350 ◽  
Author(s):  
Madhavi Indraganti ◽  
Djamel Boussaa
Keyword(s):  
Saudi Arabia ◽  
Energy Consumption ◽  
Regression Models ◽  
Outdoor Environment ◽  
Base Temperature ◽  
Degree Days ◽  
Climatic Zones ◽  
Heating And Cooling ◽  
Cooling Degree Days ◽  
Heating Degree Days

Saudi Arabia’s energy consumption is increasing astronomically. Saudi Building Code prescribes a fixed base temperature of 18.3℃ to estimate the heating degree-days and cooling degree-days. Using historical meteorological data (2005–2014), this article presents the heating degree-days and cooling degree-days estimated for the representative cities in all the five inhabited climatic zones of Saudi Arabia. We used the base temperatures of 14℃, 16℃ and 18℃ for heating degree-days, and 18℃, 20℃, 22℃, 24℃ and 28℃ for cooling degree-days for Dhahran, Guriat, Jeddah, Khamis Mushait and Riyadh cities. We developed multiple regression models for heating degree-days and cooling degree-days at various base temperatures for these zones. Degree-days for other cities in similar climates with limited input data can be computed with these. Lowering of base temperature by 2 K from 18℃ reduced the heating degree-days by 33–65%. At 14℃ of base temperature, the heating requirement reduced by 60–95%. Elevating the base temperature by 2 K from 18℃ lowered the cooling degree-days by 16–38%. At 28℃ of base temperature cooling can be completely eliminated in Khamis Mushait, and reduced by 65–92% in other cities. This observation merits rethinking about use of appropriate base temperatures that properly link the outdoor environment to reduce the energy consumption. Practical application: Using historical data, we developed regression models for predicting heating and cooling degree-days for five cities of Saudi Arabia in various climate zones without the historic data. Using these, we can estimate the changes in heating/cooling load due to the variation in base temperatures. For example, lowering base temperature by 2–4 K from 18℃ reduces the HDDs by 33–95% and elevating the base temperature by 2–4 K from 18℃ lowered the CDDs by 16–68%.

scholarly journals Building energy analysis of an industrial hall based on dynamic simulations

2018 ◽  
Vol 9 (2) ◽  
pp. 145-151
Author(s):  
D. Szagri ◽  
B. Nagy
Keyword(s):  
Energy Consumption ◽  
Reinforced Concrete ◽  
Energy Demand ◽  
Industrial Building ◽  
Dynamic Simulations ◽  
Steel Fibre Reinforced Concrete ◽  
Roof Structure ◽  
Building Simulations ◽  
Coupled Heat And Moisture ◽  
Heating Energy Demand

The aim of the paper is primarily to evaluate the heating energy demand of an industrial hall. In the study, we have made multidimensional dynamic whole building simulations for describing coupled heat and moisture behaviour and energy consumption of the building with different internal loads and compared to the calculated energy consumption of the building according to the Hungarian and Austrian regulations. The walls and roof structure of the industrial building were made with insulated panel systems, the plinth wall was built with monolithic reinforced concrete with 12 cm of XPS insulation. The floor is made of steel fibre reinforced concrete, where 10 cm XPS perimeter insulation was applied. After the calculations, we insulated the floor on the whole surface with 10 cm XPS and investigated the modified structure’s heating energy demand too. In the paper, we analyse the energy consumption of the original and modified industrial building according to the monthly and seasonal calculations and the whole building dynamic simulations and evaluated the differences. Furthermore, we assessed the effect of internal loads, thermal bridges on the simulations.

Energetic Efficiency - A New Tool, Methodology of Integrate Design for Buildings' Openings

2014 ◽  
Vol 875-877 ◽  
pp. 1812-1821
Author(s):  
Aurea Lucia Georgi Vendramin ◽  
Carlos Itsuo Yamamoto ◽  
Samuel N. Souza Melegari
Keyword(s):  
Energy Consumption ◽  
Architectural Design ◽  
Energy Performance ◽  
Design Tool ◽  
Energetic Efficiency ◽  
Base Temperature ◽  
Climatic Data ◽  
Degree Days ◽  
Total Heat Loss ◽  
Cooling Degree Days

The Residential sector in Brazil is responsible for 26% of energy consumption for illumination, refrigeration and heating, because of this there is a necessity to project in a correct way the openings and choose better materials for construction, targeting the energy rationalization. This article describes the development of a new model that uses a method where openings are represented by single glass and double glass. The model is based on a healthy balance equations purely theoretical and empirical data. Simplified equations are derived through a synthesis of the measured data obtained from meteorological stations, as well as the literature. The implementation of the model in a design tool integrated naturally lit buildings is discussed in this article, to better punctuate the requirements of comfort and energy efficiency in architecture and engineering. Assumes significant importance in studies of heatstroke buildings, aiming to guide the professionals through the process of architectural design, preliminary study and detail of construction elements. It was used a method of degree-days for an assessment of the energy performance of a building showed that the design of the architectural design should always be considered the materials used and the size of the openings. The energy performance was obtained through the model, considering the location of the building in the city of Curitiba, Foz do Iguaçu, Londrina and Cascavel - PR. Obtained climatic data of these locations and in a second step, it was obtained the coefficient of total heat loss in the building pre-established so evaluating the thermal comfort and energy performance. It was observed that heating degree days in winter are of 77.78 to Curitiba the base temperature of 14 ° C and cooling degree days in winter 30.17. For Curitiba lower air exchange, the lower the energy consumption for heating and thus the higher the intake, the greater exchange of air. This means that the more openings in buildings in Curitiba, and are installed to the east side, they may be higher because the glass added to the geometry of architectural spaces will cause the environment conserve energy.

scholarly journals Batch Reverse Osmosis Desalination Modeling under a Time-Dependent Pressure Profile

Membranes ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 173
Author(s):  
Abdeljalil Chougradi ◽  
François Zaviska ◽  
Ahmed Abed ◽  
Jérôme Harmand ◽  
Jamal-Eddine Jellal ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Reverse Osmosis ◽  
Specific Energy ◽  
Energy Demand ◽  
Specific Energy Consumption ◽  
Pressure Profile ◽  
Recovery Ratio ◽  
Feed Concentration ◽  
Energetic Performance ◽  
Feed Volume

As world demand for clean water increases, reverse osmosis (RO) desalination has emerged as an attractive solution. Continuous RO is the most used desalination technology today. However, a new generation of configurations, working in unsteady-state feed concentration and pressure, have gained more attention recently, including the batch RO process. Our work presents a mathematical modeling for batch RO that offers the possibility of monitoring all variables of the process, including specific energy consumption, as a function of time and the recovery ratio. Validation is achieved by comparison with data from the experimental set-up and an existing model in the literature. Energetic comparison with continuous RO processes confirms that batch RO can be more energy efficient than can continuous RO, especially at a higher recovery ratio. It used, at recovery, 31% less energy for seawater and 19% less energy for brackish water. Modeling also proves that the batch RO process does not have to function under constant flux to deliver good energetic performance. In fact, under a linear pressure profile, batch RO can still deliver better energetic performance than can a continuous configuration. The parameters analysis shows that salinity, pump and energy recovery devices efficiencies are directly linked to the energy demand. While increasing feed volume has a limited effect after a certain volume due to dilution, it also shows, interestingly, a recovery ratio interval in which feed volume does not affect specific energy consumption.

scholarly journals Study on the Variable-Temperature Drying Process of Corn Drying in an Industrial Corn-Drying System Equipped with a Self-Adaptive Control Heat Exchanger

2021 ◽  
Vol 11 (6) ◽  
pp. 2772
Author(s):  
Bin Li ◽  
Zhiheng Zeng ◽  
Xuefeng Zhang ◽  
Ye Zhang
Keyword(s):  
Adaptive Control ◽  
Energy Consumption ◽  
Heat Loss ◽  
Thermal Performance ◽  
Variable Temperature ◽  
The Other ◽  
Drying Process ◽  
Drying Kinetic ◽  
Drying System ◽  
Self Adaptive

To realize energy-saving and efficient industrial grain drying, the present work studied the variable-temperature drying process of corn drying in a novel industrial corn-drying system with a heat recycling and self-adaptive control function. The drying kinetics, thermal performance, heat-loss characteristics and the heat-recycling performance of the drying system under different allocations between flue gas and hot air were investigated, and the optimized drying process was proposed and compared with two constant drying processes. The results showed that the optimized drying process exhibited better drying kinetic and thermal performance than the two constant drying processes. More specifically, the total heat loss, total energy consumption and specific energy consumption of the optimized drying process were ascertained to be 36,132.85 MJ, 48,803.99 MJ and 7290.27 kJ/kg, respectively, which were lower than those of the other two processes. On the other hand, the thermal efficiency of the drying chamber for the optimized drying process was ascertained to be varied within the range of 6.81–41.71%. Overall, the validation results showed that the optimized drying process can significantly improve the drying performance of the drying system.

scholarly journals Design and Fabrication of a Novel Window-Type Convection Device

2020 ◽  
Vol 11 (1) ◽  
pp. 267
Author(s):  
Han-Tang Lin ◽  
Yunn-Horng Guu ◽  
Wei-Hsuan Hsu
Keyword(s):  
Energy Consumption ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Energy Demand ◽  
Air Entrainment ◽  
Wind Speeds ◽  
Digit Series ◽  
Slit Size ◽  
Deflector Plate

Global warming, climate change, and ever-increasing energy demand are among the pressing challenges currently facing humanity. Particularly, indoor air conditioning, a major source of energy consumption, requires immediate improvement to prevent energy crises. In this study, various airfoil profiles were applied to create a window-type convection device that entrains air to improve convection between indoor and outdoor airflows and adjust the indoor temperature. How the geometric structure of the convection device affects its air entrainment performance was investigated on the basis of various airfoil profiles and outlet slit sizes of the airflow multiplier. The airfoil profiles were designed according to the 4-digit series developed by the National Advisory Committee for Aeronautics. The results revealed that airfoil thickness, airfoil camber, and air outlet slit size affected the mass flow rate of the convection device. Overall, the mass flow rate at the outlet of the convection device was more than 10 times greater than at the inlet, demonstrating the potential of the device to improve air convection. To validate these simulated results, the wind-deflector plate was processed using the NACA4424 airfoil with a 1.2 mm slit, and various operating voltages were applied to the convection device to measure the resulting wind speeds and calculate the corresponding mass flow rates. The experimental and simulated results were similar, with a mean error of <7%, indicating that the airfoil-shaped wind-deflector plate substantially improved air entrainment of the convection device to the goal of reduced energy consumption and carbon emissions.

scholarly journals Heating and Cooling Degree-Days Climate Change Projections for Portugal

Atmosphere ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 715
Author(s):  
Cristina Andrade ◽  
Sandra Mourato ◽  
João Ramos
Keyword(s):  
Climate Change ◽  
High Resolution ◽  
Thermal Comfort ◽  
Energy Demand ◽  
Residential Buildings ◽  
Degree Days ◽  
Climate Change Projections ◽  
Heating And Cooling ◽  
Cooling Degree Days ◽  
Heating Energy Demand

Climate change is expected to influence cooling and heating energy demand of residential buildings and affect overall thermal comfort. Towards this end, the heating (HDD) and cooling (CDD) degree-days along with HDD + CDD were computed from an ensemble of seven high-resolution bias-corrected simulations attained from EURO-CORDEX under two Representative Concentration Pathways (RCP4.5 and RCP8.5). These three indicators were analyzed for 1971–2000 (from E-OBS) and 2011–2040, and 2041–2070, under both RCPs. Results predict a decrease in HDDs most significant under RCP8.5. Conversely, it is projected an increase of CDD values for both scenarios. The decrease in HDDs is projected to be higher than the increase in CDDs hinting to an increase in the energy demand to cool internal environments in Portugal. Statistically significant linear CDD trends were only found for 2041–2070 under RCP4.5. Towards 2070, higher(lower) CDD (HDD and HDD + CDD) anomaly amplitudes are depicted, mainly under RCP8.5. Within the five NUTS II

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