scholarly journals Spatial-Temporal Changes and Associated Determinants of Global Heating Degree Days

2021 ◽  
Vol 18 (12) ◽  
pp. 6186
Author(s):  
Yuanzheng Li ◽  
Jinyuan Li ◽  
Ao Xu ◽  
Zhizhi Feng ◽  
Chanjuan Hu ◽  
...  
Keyword(s):  
Thermal Environment ◽  
Winter Season ◽  
Climate Impact ◽  
Temporal Changes ◽  
Degree Days ◽  
Source Data ◽  
Nighttime Light ◽  
Winter Annual ◽  
Heating Degree Days ◽  
Pm2.5 Concentration

The heating degree days (HDDs) could indicate the climate impact on energy consumption and thermal environment conditions effectively during the winter season. Nevertheless, studies on the spatial-temporal changes in global HDDs and their determinants are scarce. This study used multi-source data and several methods to explore the rules of the spatial distribution of global HDDs and their interannual changes over the past 49 years and some critical determinants. The results show that global HDDs generally became larger in regions with higher latitudes and altitudes. Most global change rates of HDDs were negative (p < 0.10) and decreased to a greater extent in areas with higher latitudes. Most global HDDs showed sustainability trends in the future. Both the HDDs and their change rates were significantly partially correlated with latitude, altitude, mean albedo, and EVI during winter, annual mean PM2.5 concentration, and nighttime light intensity (p = 0.000). The HDDs and their change rates could be simulated well by the machine learning method. Their RMSEs were 564.08 °C * days and 3.59 °C * days * year−1, respectively. Our findings could support the scientific response to climate warming, the construction of living environments, sustainable development, etc.

Heating degree–days for arid regions

Energy ◽  
1998 ◽  
Vol 23 (12) ◽  
pp. 1089-1094 ◽  
Author(s):  
Zekai Şen ◽  
Mikdat Kadiogl̂u
Keyword(s):  
Arid Regions ◽  
Degree Days ◽  
Heating Degree Days

scholarly journals Interactions Between Chill-Hours and Degree-Days Affect Carpogenic Germination in Monilinia vaccinii-corymbosi

2001 ◽  
Vol 91 (1) ◽  
pp. 77-83 ◽  
Author(s):  
H. Scherm ◽  
A. T. Savelle ◽  
P. L. Pusey
Keyword(s):  
Laboratory Experiments ◽  
Field Experiments ◽  
Degree Days ◽  
Carpogenic Germination ◽  
Conditioning Period ◽  
Low Degree ◽  
Heating Degree Days ◽  
Relationship Of ◽  
High Degree ◽  
The Relationship

The relationship of cumulative chill-hours (hours with a mean temperature <7.2°C) and heating degree-days (base 7.2°C) to carpogenic germination of pseudosclerotia of Monilinia vaccinii-corymbosi, which causes mummy berry disease of blueberry, was investigated. In two laboratory experiments, pseudosclerotia collected from rabbiteye blueberry in Georgia were conditioned at 5 to 6°C for 26 to 1,378 h prior to placement in conditions favorable for germination and apothecium development. The number of chill-hours accumulated during the conditioning period affected the subsequent proportion of pseudosclerotia that germinated and produced apothecia, with the greatest incidence of carpogenic germination occurring after intermediate levels of chilling (≈700 chill-hours). The minimum chilling requirement for germination and apothecium production was considerably lower than that reported previously for pseudo-sclerotia from highbush blueberry in northern production regions. The rate of carpogenic germination was strongly affected by interactions between the accumulation of chill-hours and degree-days during the conditioning and germination periods; pseudosclerotia exposed to prolonged chilling periods, once transferred to suitable conditions, germinated and produced apothecia more rapidly (after fewer degree-days had accumulated) than those exposed to shorter chilling periods. Thus, pseudosclerotia of M. vaccinii-corymbosi are adapted to germinate carpogenically following cold winters (high chill-hours, low degree-days) as well as warm winters (low chill-hours, high degree-days). Results were validated in a combined field-laboratory experiment in which pseudosclerotia that had received various levels of natural chilling were allowed to germinate in controlled conditions in the laboratory, and in two field experiments in which pseudosclerotia were exposed to natural chilling and germination conditions. A simple model describing the timing of apothecium emergence in relation to cumulative chill-hours and degree-days was developed based on the experiments. The model should be useful for better timing of field scouting programs for apothecia to aid in management of primary infection by M. vaccinii-corymbosi.

Climate Change as a Driving Force on Urban Energy Consumption Patterns

2018 ◽  
pp. 7815-7830
Author(s):  
Mostafa Jafari ◽  
Pete Smith
Keyword(s):  
Energy Consumption ◽  
Pearson Correlation ◽  
Consumption Patterns ◽  
Time Slice ◽  
Degree Days ◽  
Urban Energy ◽  
Cooling Degree Days ◽  
Energy Consumption Patterns ◽  
Annual Total ◽  
Heating Degree Days

Heating Degree Days (HDD), in cases where temperatures are below 18°C, and Cooling Degree Days (CDD), in cases where temperatures are above 21°C, were used as energy consumption indices. During the last half century, mean annual temperatures have increased and as a consequence, CDD in the warm season have increased sharply. In the same time slice, HDD, even in the cool and cold season have declined steadily. The number of monthly and annual total HDD (mean= 1556) are much higher than CDD (mean=400) in the case study area and annual total HDD and CDD have a negative correlation (Pearson correlation = - 0.493; p = 0.001). The deceasing rate of HDD is limited and steady (R2= 0.062, p=0.099), but the increasing rate of CDD in the same time slice is sharp (R2=0.427, p=0.813). This shows that energy consumption patterns have increased sharply, and with available projection scenarios, is projected to increase more rapidly, leading to higher energy costs.

scholarly journals Energy conservation by retrofitting of dwellings

2019 ◽  
Vol 111 ◽  
pp. 03010
Author(s):  
Imrich Sánka ◽  
Dušan Petráš
Keyword(s):  
Large Scale ◽  
Thermal Environment ◽  
Winter Season ◽  
Residential Building ◽  
Indoor Environmental Quality ◽  
Air Exchange Rate ◽  
Energy Auditing ◽  
Before And After ◽  
The Impact

This article investigates the impact of energy renovation on the indoor environmental quality of apartment building during heating season. The study was performed in one residential building before and after its renovation. Energy auditing and classification of the selected building into energy classes were carried out. Additionally, evaluation of indoor air quality was performed using objective measurements and subjective survey. Thermal environment and concentration of CO2 was measured in bedrooms. Higher concentrations of CO2 was observed in the residential building after its renovation. The concentrations of CO2, in some cases exceeded the recommended maximum limits, especially after implementing of energy saving measures on the building. The average air exchange rate was visible higher before renovation of the building. The current study indicates that large-scale of renovations may reduce the quality of the indoor environment in many apartments, especially in the winter season.

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