The Potential of Sky Radiation for Humidity Control

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
Zachary Springer ◽  
M. Keith Sharp
Keyword(s):  
Storage Capacity ◽  
Volume Flow Rate ◽  
Dew Point ◽  
Weather Data ◽  
Cooling Load ◽  
Floor Area ◽  
Space Cooling ◽  
Latent Space ◽  
Mountain West ◽  
Cooling Loads

The potential of sky radiation (SR) to serve the latent space cooling loads was evaluated. Using ASHRAE standard 55 comfort limits (room temperature 22 °C, relative humidity 60%, and dew-point temperature 13.9 °C), condensation was the chosen mechanism for humidity reduction. Typical meteorological year (TMY3) weather data were used for eleven ASHRAE climate zones. Three values of load-to-radiator ratio (LRR) (infiltration/ventilation volume flow rate times the ratio of building floor area to radiator area) were evaluated: 0.35, 3.5, and 35 m/h. Three thermal storage cases were considered: 1. Annual cooling potential, 2. Diurnal storage, and 3. Minimum storage capacity to serve the entire annual load. Six SR temperatures Trad = 13.9 to −26.1 °C were tested. Even in the most challenging climates, annual SR potential exceeded the total sensible and latent cooling load, at least for the lowest LRR and the highest Trad. For diurnal storage, SR served less than 20% of the load in the hot and humid southeast, but the entire load in the mountain west. The minimum storage capacity to meet the entire annual load decreased with decreasing LRR and decreasing Trad. For the southeast, large capacity was required, but for Louisville, for instance, sufficient capacity was provided by 0.05 m3 of water per m2 of floor area for LRR = 0.35 m/h. These results demonstrate that for much of the U.S., sky radiation has the potential to serve the entire annual sensible and latent cooling load.

The Potential of Night Sky Radiation for Humidity Control

2015 ◽  
Author(s):  
Zachary Springer ◽  
M. Keith Sharp
Keyword(s):  
Storage Capacity ◽  
Volume Flow Rate ◽  
Ambient Air ◽  
Dew Point ◽  
Weather Data ◽  
Cooling Load ◽  
Floor Area ◽  
The Us ◽  
Night Sky ◽  
Mountain West

Ambient energy sources, including ambient air, ground and night sky, have potential for space cooling. The night sky offers the lowest temperature and, therefore, the greatest potential across most of the US. Compared to a previous analysis that considered only the sensible cooling load, the objective of this new project was to evaluate the potential of night-sky radiation (NSR) to also serve the latent cooling load. ASHRAE standard 55 was used to establish the comfort limits (22°C for room temperature and 60% relative humidity). Condensation was evaluated as the mechanism for humidity reduction, thus the dew-point temperature, 13.9°C, corresponding to the ASHRAE limits was the maximum target temperature for night-sky cooling. Typical meteorological year (TMY3) weather data was used for eleven locations representing ASHRAE climate zones. Building heat gain, infiltration/ventilation requirements and night-sky radiator size were characterized by a load-to-radiator ratio LRR defined as the infiltration/ventilation volume flow rate times the ratio of building floor area to radiator area. Three values of LRR were evaluated: 0.35, 3.5 and 35 m/hr. Three thermal storage cases were considered: 1. Annual NSR cooling potential (seasonal storage), 2. Diurnal storage, and 3. The minimum storage capacity to serve the entire annual load, as well as the effects of capacity less than the minimum. To evaluate the effect of night-sky radiator temperature on storage capacity, six NSR temperatures Trad = 13.9 to −26.1°C were tested. Results showed that even in Miami, FL (the most challenging climate evaluated), annual NSR potential exceeded the total sensible and latent cooling load, at least for the lowest LRR and highest Trad. For diurnal storage, NSR could serve less than 20% of the load in the hot and humid southeast, but the entire load in the mountain west. The minimum storage capacity to meet the entire annual load corresponds to the capacity required to bridge the span of time without NSR availability during which the largest cooling load occurs. This capacity decreases with decreasing LRR and decreasing Trad. For the southeast, large capacity is required, but for Louisville, for instance, sufficient capacity is provided by the equivalent of as little as 0.05 m of water over the floor area of the building for LRR = 0.35 m/hr. These results demonstrate that for much of the US, night-sky radiation has the potential to serve the entire annual sensible and latent cooling load.

The Potential of Sky Radiation With Change in Design Parameters

2016 ◽  
Author(s):  
Adrienne M. Parsons ◽  
M. Keith Sharp
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Heat Pipe ◽  
New Orleans ◽  
Storage Capacity ◽  
Thermal Storage ◽  
Ambient Air ◽  
Dew Point ◽  
Cooling Load ◽  
Tank Wall

This study evaluated the building cooling capacity of sky radiation, which was previously identified to have the greatest cooling potential among common ambient sources for climates across the US. [Robinson, et al. 2013b]. A heat pipe augmented sky radiator system was simulated by a thermal network with nine nodes, representing a thin polyethylene cover, white (ZnO) painted radiator plate [Duffie & Beckman 2013], condenser and evaporator ends of the heat pipe, thermal storage fluid (water), tank wall, room, sky and ambient air. Heat transfer between nodes included solar flux and sky radiation to cover and plate, wind convection and radiation from cover to ambient, radiation from plate to ambient, natural convection and radiation from plate to cover, conduction from plate to condenser or, two-phase heat transfer from evaporator to condenser, natural convection from evaporator to water and from water to tank wall, natural convection and radiation from tank wall to room, and overall heat loss from room to ambient. Nodal temperatures were simultaneously solved as functions of time using Typical Meteorological Year (TMY3) weather data. Auxiliary cooling was applied as needed to limit room temperature to a maximum of 23.9°C. For this initial investigation, a moderate climate (Louisville, KY) was used to evaluate the effects of radiator orientation, thermal storage capacity and cooling load to radiator area ratio, LRR. Louisville and two challenging climates (Miami, FL and New Orleans, LA) were then used to evaluate five cover configurations — zero, one and two covers with unconstrained temperature, and zero and one cover with temperature limited to the dew point of ambient air to simulate condensation on the cover. Results were compared to a Louisville baseline with LRR = 10 W/m2K, horizontal radiator and one cover with constrained temperature, which provided an annual sky fraction (fraction of cooling load provided by sky radiation) of 0.861. A decrease to 0.857 was found for an increase in radiator slope to 20°, and a drop to 0.833 for 53° slope (latitude + 15°, a typical slope for solar heating). These drops were associated with increases in average radiator temperature by 0.2°C for 20° and 1.5°C for 53°. A 25% decrease in storage capacity caused a decrease in sky fraction to 0.854. Sky fractions were 0.727 and 0.963 for LRR of 20 and 5, respectively. Sky fractions for the baseline system in Miami and New Orleans were 0.505 and 0.603, respectively. In all three climates, performance was little affected by constraining the cover temperature and by adding a second cover. These results confirm the potential for passive cooling of buildings by radiation to the sky. Climate, LRR and thermal storage capacity had strong effects on performance, while the cover configuration did not. Radiator slope had a surprisingly small impact, considering that the view factor to the sky at 53° tilt is less than 0.5.

scholarly journals ANALYSIS OF ENERGY-EFFICIENT HOUSE LAYOUT DESIGN IN TROPICAL CLIMATE

2021 ◽  
Vol 47 (1) ◽  
pp. 11-18
Author(s):  
Aisyah Zakiah
Keyword(s):  
Energy Consumption ◽  
Energy Efficient ◽  
Residential Buildings ◽  
Weather Data ◽  
Cooling Load ◽  
City Development ◽  
Total Energy Consumption ◽  
Wall Area ◽  
Consumption Energy ◽  
Cooling Loads

Energy-efficient residential provision is an essential concern for the present and future city development. Currently, the residential buildings contribute approximately 37.5% to significant energy consumption and carbon emissions, which mainly used for cooling. This research aims to study the house layout arrangement to minimise cooling loads and further reduce energy consumption. Energy efficiency analysis is performed by comparing the cooling load and total energy consumption from variations of the hypothetical design of detached or semi-detached housing layouts commonly built in Indonesia. The calculation of cooling loads and energy consumption is performed by simulation in Energy Plus 8.4 with Jakarta weather data. The results show that the arrangement of the house layout may reduce the cooling load up to 24%. The total conditioned wall area that varies due to the variations of house layouts are found to affect the cooling loads.

Effect of Thermal Storage on the Cooling Capacity of Ambient Sources

2014 ◽  
Author(s):  
Brian S. Robinson ◽  
M. Keith Sharp
Keyword(s):  
Storage Capacity ◽  
Thermal Storage ◽  
Ambient Air ◽  
Cooling Capacity ◽  
Ground Temperature ◽  
Cooling Load ◽  
Space Cooling ◽  
Wide Range ◽  
Sky Temperature ◽  
Night Sky

Ambient sources, including ambient air at dry-bulb and wet-bulb temperature, ground temperature and night sky temperature, were evaluated for their potential to provide space cooling in locations across the U.S. While ground temperature is constant beyond a certain depth, the other sources have fluctuating temperatures, which present intermittent potentials for cooling. Simultaneously, cooling demands also fluctuate with outdoor temperature. Thermal storage can bridge intervals of time during which cooling is needed in the building, but ambient source temperature is too high to provide cooling. The duration of these intervals and the thermal storage capacity required to meet cooling needs based on ambient source potential prior to the interval were quantified for all eleven climate zones across the continental U.S using TMY3 weather data. The thermal storage capacity required to meet the entire annual cooling load is dictated by the span of time without ambient source cooling potential that has the greatest ratio of cooling load to ambient source cooling potential prior to the interval. This maximum thermal storage capacity, normalized by building overall loss coefficient, (this ratio has units of time) was one day or less for night sky temperature for all but the three warmest climates. This ratio was one day or less for wet-bulb temperature for four locations, and for dry-bulb temperature for only two locations. Ground temperature provided continuous cooling potential in all but the three warmest climates, where ground temperature was warmer than the indoor comfort temperature. Because the maximum thermal storage capacity was determined in most climates by uncommon and infrequent coincidence of high cooling demand and low ambient source cooling potential, smaller thermal storage provided substantial cooling capacity in most cases. For instance, ten percent of the maximum supplied 99% of the cooling load for the dry-bulb ambient air source in Albuquerque, and 0.1% of the maximum served over 90% of the cooling load with night sky radiation in New Orleans and Phoenix. While considerable development of hardware and control algorithms to utilize ambient sources for space cooling has occurred, this study shows the potential of these sources to further reduce demands for conventional energy for space cooling across a wide range of climates.

scholarly journals Towards Sustainable Energy Retrofitting, a Simulation for Potential Energy Use Reduction in Residential Buildings in Palestine

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3876
Author(s):  
Sameh Monna ◽  
Adel Juaidi ◽  
Ramez Abdallah ◽  
Aiman Albatayneh ◽  
Patrick Dutournie ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Energy Use ◽  
Energy Savings ◽  
Residential Buildings ◽  
Residential Building ◽  
Simulation Models ◽  
Water Heating ◽  
Heating And Cooling ◽  
Space Cooling ◽  
Cooling Loads

Since buildings are one of the major contributors to global warming, efforts should be intensified to make them more energy-efficient, particularly existing buildings. This research intends to analyze the energy savings from a suggested retrofitting program using energy simulation for typical existing residential buildings. For the assessment of the energy retrofitting program using computer simulation, the most commonly utilized residential building types were selected. The energy consumption of those selected residential buildings was assessed, and a baseline for evaluating energy retrofitting was established. Three levels of retrofitting programs were implemented. These levels were ordered by cost, with the first level being the least costly and the third level is the most expensive. The simulation models were created for two different types of buildings in three different climatic zones in Palestine. The findings suggest that water heating, space heating, space cooling, and electric lighting are the highest energy consumers in ordinary houses. Level one measures resulted in a 19–24 percent decrease in energy consumption due to reduced heating and cooling loads. The use of a combination of levels one and two resulted in a decrease of energy consumption for heating, cooling, and lighting by 50–57%. The use of the three levels resulted in a decrease of 71–80% in total energy usage for heating, cooling, lighting, water heating, and air conditioning.

scholarly journals A Typical Meteorological Year Generation Based on NASA Satellite Imagery (GEOS-I) for Sokoto, Nigeria

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Olayinka S. Ohunakin ◽  
Muyiwa S. Adaramola ◽  
Olanrewaju M. Oyewola ◽  
Richard L. Fagbenle ◽  
Fidelis I. Abam
Keyword(s):  
Energy Systems ◽  
Building Energy ◽  
Global Solar Radiation ◽  
Dew Point ◽  
Weather Data ◽  
Maximum Temperature ◽  
Building Energy Simulation ◽  
Dew Point Temperature ◽  
Northwest Region

Computer simulation of buildings and solar energy systems are being used increasingly in energy assessments and design. This paper evaluates the typical meteorological year (TMY) for Sokoto, northwest region, Nigeria, using 23-year hourly weather data including global solar radiation, dew point temperature, mean temperature, maximum temperature, minimum temperature, relative humidity, and wind speed. Filkenstein-Schafer statistical method was utilized for the creation of a TMY for the site. The persistence of mean dry bulb temperature and daily global horizontal radiation on the five candidate months were evaluated. TMY predictions were compared with the 23-year long-term average values and are found to have close agreement and can be used in building energy simulation for comparative energy efficiency study.

Thermal performance of silica aerogel-filled double-layer glazing in a subtropical climate

2021 ◽  
Vol 11 (6) ◽  
pp. 974-981
Author(s):  
Yajun Lv ◽  
Yiming Qin ◽  
Julian Wang ◽  
Kui Yin ◽  
Huanchun Huang ◽  
...  
Keyword(s):  
Double Layer ◽  
Silica Aerogel ◽  
Energy Efficient ◽  
Air Conditioning ◽  
Weather Conditions ◽  
Research Topic ◽  
Outdoor Environment ◽  
Subtropical Climate ◽  
Cooling Load ◽  
Space Cooling

Heat gain through glazing is a major source of the space cooling load in subtropical cooling-dominant climates. Application of energy-efficient glazing systems can significantly reduce the energy consumption of air conditioning in summer. Thus, it has become a popular research topic. In this study, a sample of silica aerogel glazing was developed and prepared. Two identical insulated boxes were then constructed; one faÇade was equipped with the aerogel glazing sample and the other was prepared with a conventional double-layer glazing. An onsite measurement of the boxes’ internal thermal properties was then conducted. The two boxes were placed within the same outdoor environment. The temperature, humidity, and enthalpy values were calculated with the boxes facing different orientations and in a variety of weather conditions. The performance of the silica aerogel glazing was then evaluated by both experimental and theoretical analysis. The results of this study will provide a basis for aerogel glass building application guidelines.

scholarly journals A NILM method for cooling load disaggregation based on artificial neural network

2019 ◽  
Vol 111 ◽  
pp. 05020 ◽  
Author(s):  
Ziwei Xiao ◽  
Jiaqi Yuan ◽  
Wenjie Gang ◽  
Chong Zhang ◽  
Xinhua Xu
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Energy Management ◽  
Residential Buildings ◽  
Building Energy ◽  
Cooling Load ◽  
Building Energy Management ◽  
Load Disaggregation ◽  
Artificial Neural ◽  
Cooling Loads

The demand of building energy management has increased due to high energy saving potentials. Load monitor and disaggregation can provide useful information for building energy management systems with detailed and individual loads of the building, so corresponding energy efficient measures can be taken to reduce the energy consumption of buildings. The technique is investigated widely in residential buildings known as Non-Intrusive Load Monitoring (NILM). However, relevant studies are not sufficient for non-residential buildings, especially for the cooling loads. This paper proposes a NILM method for cooling load disaggregation using artificial neural network. The cooling load is disaggregated into four categories: building envelope load, occupant load, equipment load and fresh air load. Two approaches are used to realize the load disaggregation: one is based on the Fourier transfer of the cooling loads, the other takes the cooling load, dry-bulb temperature and humidity of outdoor air, and time as inputs. By implementing the methods in a metro station, the performance of the proposed method can be obtained. Results show that both approaches can realize the load disaggregation accurately, with a RMSE less than 11.2. The second approach is recommended with a higher accuracy.

Prediction and Analysis of Building Energy Efficiency Using Artificial Neural Network and Design of Experiments

2016 ◽  
Vol 819 ◽  
pp. 541-545 ◽  
Author(s):  
Sholahudin ◽  
Azimil Gani Alam ◽  
Chang In Baek ◽  
Hwataik Han
Keyword(s):  
Neural Network ◽  
Energy Efficient ◽  
Residential Buildings ◽  
Building Energy ◽  
Cooling Load ◽  
Simulation Data ◽  
Heating And Cooling ◽  
Heating Load ◽  
Input Variables ◽  
Cooling Loads

Energy consumption of buildings is increasing steadily and occupying approximately 30-40% of total energy use. It is important to predict heating and cooling loads of a building in the initial stage of design to find out optimal solutions among various design options, as well as in the operating stage after the building has been completed for energy efficient operation. In this paper, an artificial neural network model has been developed to predict heating and cooling loads of a building based on simulation data for building energy performance. The input variables include relative compactness, surface area, wall area, roof area, overall height, orientation, glazing area, and glazing area distribution of a building, and the output variables include heating load (HL) and cooling load (CL) of the building. The simulation data used for training are the data published in the literature for various 768 residential buildings. ANNs have a merit in estimating output values for given input values satisfactorily, but it has a limitation in acquiring the effects of input variables individually. In order to analyze the effects of the variables, we used a method for design of experiment and conducted ANOVA analysis. The sensitivities of individual variables have been investigated and the most energy efficient solution has been estimated under given conditions. Discussions are included in the paper regarding the variables affecting heating load and cooling load significantly and the effects on heating and cooling loads of residential buildings.

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