scholarly journals Evaluation of natural gas saving measures in public educational institutions

2020 ◽  
Vol 6 (2) ◽  
pp. 88-96
Author(s):  
Volodymyr Pashkevich ◽  
◽  
Yuriy Furdas ◽  
Volodymyr Craiovsky ◽  
Vasyl Zhelykh
Keyword(s):  
Air Temperature ◽  
Indoor Air ◽  
Temperature Regime ◽  
Educational Institutions ◽  
Outdoor Air ◽  
Air Temperatures ◽  
Mode Of Operation ◽  
Boiler Room ◽  
Gas Consumption ◽  
Heat Loads

The article analyzes the data of gas consumption for the heating periods and confirms that for the actual outdoor air temperatures there is a decrease in gas consumption. Necessary heat loads and gas consumption were determined to ensure the required indoor air temperature in the premises of the educational buildings with the proposed mode of gas savings by lowering the indoor air temperature, the so-called economical mode of operation of the boiler room. The theoretical economy of gas from lowering the temperature regime is determined. To increase the accuracy of the experiment, the comparison of the amount of gas consumed was performed in terms of working and non-working periods of the day. Based on these studies, it should be noted that the actual plot can be used to determine the actual gas savings in real conditions.

scholarly journals The Effect of Supply and Outdoor Air Temperature on The Enthalpy and Temperature Exchange Efficiency of a Paper Heat Exchanger

2021 ◽  
Vol 335 ◽  
pp. 03015
Author(s):  
Teoh Zhi Heng ◽  
Abudulkareem Sh. Mahdi Al-Obaidi ◽  
Chin Wai Meng ◽  
Kenny James Ling Neng Hui
Keyword(s):  
Heat Exchanger ◽  
Air Temperature ◽  
Indoor Air ◽  
Numerical Models ◽  
Outdoor Air ◽  
Iso Standard ◽  
Air Temperatures ◽  
Temperature Exchange ◽  
Main Component ◽  
Complex Cases

Heat Recovery Ventilator (VHR) is widely used nowadays as it is capable to maintain high Indoor Air Quality (IAQ) while minimizing the energy loss of indoor air through air-to-air heat exchanger principle. The main component that enables VHR to perform air-to-air heat exchange is known as Paper Heat Exchanger (PP-HEX). Hence, the objective of this research is to study and analyse the performance of a PP-HEX under different return and outdoor air temperatures as well as their effect on both enthalpy and temperature exchange efficiency. Moreover, some numerical models of VHR have been developed to optimize some complex cases and the numerical models are meant to reduce the physical experiments to analyze or improve complex cases in the future. To the best of the authors knowledge, there is no experimental data available from any sources to validate the numerical models. To address this issue, two different supplies of PP-HEX are tested with an actual VHR, and both PP-HEXs will be referred to as PP-HEX-A and PP-HEX-B due to confidentiality. Furthermore, the testing is conducted in a temperature-controlled testing laboratory and the testing conditions are set according to the ISO standard. The preliminary testing results show that the temperature exchange efficiency and enthalpy exchange efficiency of the PP-HEXs have the same trends while the outdoor air temperature is fixed and varying the temperature of indoor air. In contrary, the temperature exchange efficiency and enthalpy exchange efficiency of the PP-HEXs have the same trends while the indoor air temperature is fixed and varying the temperature of outdoor air as well. With the default voltage supplies (240V) to VHR and the setup conditions (according to the ISO Standard) of return air to be 27°C and outdoor air to be 35°C, the testing results show that PP-HEX-A has a temperature exchange efficiency and enthalpy exchange efficiency with a range of (37.97 – 40.28) % and (30.77 – 57.81) % respectively. While PP-HEX-B has a temperature exchange efficiency and enthalpy exchange efficiency with a range of (35.29 – 42.5) % and (39.6 – 55.93) % respectively.

Thermal influence of sunshine and clothing on men walking in humid heat

1962 ◽  
Vol 17 (2) ◽  
pp. 311-316 ◽  
Author(s):  
F. N. Craig ◽  
E. G. Cummings
Keyword(s):  
Body Temperature ◽  
Temperature Gradient ◽  
Air Temperature ◽  
Indoor Air ◽  
Physiological Strain ◽  
Mean Body Temperature ◽  
Clothing Insulation ◽  
Air Temperatures ◽  
Rate Of Increase ◽  
Thermal Influence

For two men walking on a treadmill and wearing two layers of permeable clothing, the same physiological strain measured by the rate of increase in mean body temperature could be produced a) next to a building outdoors in the sunshine with an average air temperature of 85 F and humidity of 20 mm Hg and b) indoors with the same humidity and an air temperature 10 F higher. Under these conditions, the underwear was mainly wet with sweat and the outer layer was mainly dry. In comparable indoor tests on a third subject, the temperature of the underwear approached equilibrium 1 or 2 F lower than the temperature of the skin at air temperatures of 85 and 115 F. The error in calculating clothing insulation introduced by assuming the clothing to be dry is determined by the size and direction of the temperature gradient between skin and air. Adding 10 F to the indoor air temperature does not duplicate all the effects of sunshine. Submitted on September 15, 1961

scholarly journals Comparative thermal performance of static sunshade and brick cavity wall for energy efficient building envelope in composite climate

2014 ◽  
Vol 18 (3) ◽  
pp. 925-934 ◽  
Author(s):  
Meghana Charde ◽  
Sourabh Bhati ◽  
Ayushman Kheterpal ◽  
Rajiv Gupta
Keyword(s):  
Energy Consumption ◽  
Air Temperature ◽  
Indoor Air ◽  
Energy Efficient ◽  
Building Envelope ◽  
Combined Effect ◽  
Cavity Wall ◽  
Outdoor Air ◽  
Reduce Energy Consumption ◽  
Energy Efficient Building

Energy efficient building technologies can reduce energy consumption in buildings. In present paper effect of designed static sunshade, brick cavity wall with brick projections and their combined effect on indoor air temperature has been analyzed by constructing three test rooms each of habitable dimensions (3.0 m ? 4.0 m ? 3.0 m) and studying hourly temperatures on typical days for one month in summer and winter each. The three rooms have also been simulated using a software and the results have been compared with the experimental results. Designed static sunshade increased indoor air temperature in winter while proposed brick cavity wall with brick projections lowered it in summer. Combined effect of building elements lowered indoor air temperature in summer and increased it in winter as compared to outdoor air temperature. It is thus useful for energy conservation in buildings in composite climate.

scholarly journals The Impact of Infiltration on Heating Systems Dimensioning in Estonian Climate

2020 ◽  
Vol 172 ◽  
pp. 05004
Author(s):  
Raimo Simson ◽  
Taaniel Rebane ◽  
Martin Kiil ◽  
Martin Thalfeldt ◽  
Jarek Kurnitski
Keyword(s):  
Air Temperature ◽  
Indoor Air ◽  
Energy Performance ◽  
Simulation Software ◽  
Heat Losses ◽  
Climatic Data ◽  
Heating Systems ◽  
Air Temperatures ◽  
The Impact ◽  
Calculation Models

In this study we analysed the climatic conditions for infiltration estimation, different calculation methods and infiltration impact on heat load for heating systems dimensioning. To determine the wind conditions at low air temperatures of the coastal- and inland climatic zones in Estonia, 42 years of climatic data for Tallinn and Tartu were investigated. Calculation models with detailed air leakages were constructed of a single and two-storey detached house using dynamic simulation software IDA ICE. Simulations were carried out with the constructed calculation models, simulating various wind and sheltering conditions to determine the heating load of the buildings under measured wind conditions at the design external air temperatures. The simulation results were compared with results calculated with European Standard EN 12831:2017, methodology given in the Estonian regulation for calculating energy performance of buildings and with simulations using the default settings in IDA ICE based on the ASHRAE design day conditions. The percentage of heat losses caused by infiltration was found as 13-16% of all heat losses for the studied buildings. Simulations with historical climate periods showed that even in windy weather conditions the heating system dimensioned by the methods analysed may not be able to provide the required indoor air temperature. Analysis using the coldest and windiest periods showed that when systems are dimensioned by the studied methods, the highest decline in indoor air temperature occurs on the windiest day and not on the coldest day. The impact of high wind speeds and low sheltering conditions resulted up to 50% of all heat losses.

scholarly journals Microbiome in an Office Building Using a Cooling Trench as an Outdoor Air Duct

2019 ◽  
Vol 111 ◽  
pp. 06045
Author(s):  
Mizuki Niimura ◽  
U Yanagi
Keyword(s):  
Relative Humidity ◽  
Energy Saving ◽  
Air Temperature ◽  
Indoor Air ◽  
Principal Coordinate Analysis ◽  
Office Building ◽  
Metagenomic Analysis ◽  
Outdoor Air ◽  
Energy Saving Technique ◽  
Building Cooling

Subterranean temperature at a depth of 10 m is almost equal to the average outdoor air temperature of the same area. Therefore, if a building cooling trench is used as an outdoor air duct, outdoor air can be cooled in summer and warmed in winter. This energy-saving technique is often used in Japan. However, since the relative humidity in a cooling trench is high, microbe numbers tend to increase in summer. The present study sought to characterize the microbiome status in the cooling trench of such an office building in Japan. Specifically, we performed a metagenomic analysis in which we analyzed DNA directly upon collection from the environment, without intervening cultivation. The results showed the presence of bacteria of the genera Pseudomonas, Lactobacillus, Nesterenkonia, Staphylococcus, Deinococcus, Acinetobacter, Enhydorobacter, and Corynebacterium. Bacteria of the genera Nesterenkonia, Deinococcus, Enhydorobacter, and Corynebacterium predominated on the surface of the trench. Notably, bacteria of the genus Nesterenkonia constituted >50% of the organisms on the surface of the downstream end of the cooling trench. Principal coordinate analysis was used to compare bacterial inhabitants of outdoor air, indoor air from 2nd- and 3rdfloor offices, and the region downstream of the cooling trench. The results suggested that the microbiome of air in this cooling trench influenced indoor air within the building.

scholarly journals Identifying the influence of dams and ponds on the thermal regime at regional scale: The case of Loire catchment

2020 ◽  
Author(s):  
Hanieh Seyedhashemi ◽  
Florentina Moatar ◽  
Jean-Philippe Vidal ◽  
Aurélien Beaufort ◽  
André Chandesris ◽  
...  
Keyword(s):  
Time Series ◽  
Air Temperature ◽  
Temperature Regime ◽  
Thermal Regime ◽  
Regional Scale ◽  
Stream Temperature ◽  
Annual Peak ◽  
Air Temperatures ◽  
Catchment Areas ◽  
Anthropogenic Structures

<p>Human activities and natural processes are the main drivers of the spatio-temporal variability of thermal regime. Despite a few local studies on the thermal regime variability, regional assessments are scarce in the scientific literature. However, regional assessments allow tracing systematic human-induced changes emerging from some types of anthropogenic structures like dams or ponds and identifying the locations of highly influenced reaches.</p><p>In the current study, we propose a framework to detect the influence of dams and ponds on stream temperature. We use observational data from 526 evenly distributed hourly stream temperature stations in the Loire River catchment, France (110,000 km<sup>2</sup>). The data consist of unbalanced time series of natural and altered thermal regimes that contain at least 80 summer days from 2000–2018. By comparing time series of observed stream temperature and air temperature, we define five indicators to distinguish different patterns of thermal regime. Three of them are based on weekly stream-air temperature linear regressions (slope; intercept; and coefficient of determination). The remaining two indicators compare monthly air and stream temperature regime: 1) the proportion of times stream temperature is greater than air temperature from March–October (“frequency”), and 2) the lag time between the annual peak in air temperature and annual peak in stream temperature (“shift”).</p><p>K-means clustering partitioned stations into three clusters: 1) pond-like, 2) dam-like 3) and natural, with 164, 37, and 316 stations, respectively. Supporting this cluster analysis, 93% of stations in pond-like cluster have upstream ponds, and 55% of stations in dam-like cluster have upstream large dams. Pond-like stations have the greatest slope between weekly stream and air temperatures (slope = 0.4) and have stream temperatures greater than air temperatures more frequently (68%) than other clusters. In contrast, dam-like stations have the lowest correlations between weekly stream and air temperatures (mean R<sup>2</sup>=0.3, compared to 0.7 for the other two clusters). Dam-like stations also exhibit the largest shifts in stream thermal regime relative to air temperature (mean shift = 30 days). Impounded runoff index (IRI), the ratio of reservoir volume to annual discharge, best explaines variability within the dam-like cluster. For pond-like stations, catchment areas and mean upstream ponded surface area best explain the within-cluster variability, particularly for the frequency indicator, although this relationship is sensitive to interannual air temperature regime.</p><p>These findings support modelers in quantifying the downstream impacts of different types of anthropogenic structures and managers in surveying and monitoring stream networks through identification of critical reaches.</p>

Skin folds and Merino breeding. 5. Variations in scrotal, testis, and rectal temperatures as affected by site of measurement, acclimatization to heat and degree of skin fold

1968 ◽  
Vol 8 (31) ◽  
pp. 125 ◽  
Author(s):  
DG Fowler
Keyword(s):  
High Temperatures ◽  
Air Temperature ◽  
Heat Tolerance ◽  
Temperature Regime ◽  
Low Temperatures ◽  
Air Temperatures ◽  
Skin Fold ◽  
Fold Type

In Merino rams, subcutaneous temperature in the scrotum declined from the inguinal border to the distal tip and from posterior to anterior. Testicular temperature was similar at several sites in both testes. Of the total increase in scrotal and testicular temperatures that occurred when rams were heated, the proportional hourly increases were similar at each air temperature above 30�C irrespective of the air temperature regime (stepwise increasing or stepwise decreasing air temperatures) or fold type of the ram. The response of rams depended markedly on the air temperature regime. When air temperatures were decreasing, rams were less able to withstand high temperatures and more able to withstand low temperatures. When air temperatures were increasing the reverse was true. The differences between Folds Plus and Folds Minus rams also depended markedly on the ail temperature regime. In general Folds Minus rams had lower rectal temperatures than Folds Plus rams, but could express their ability to maintain lower subcutaneous scrotal temperatures than Folds Plus rams only after they had gained a degree of acclimatization to heat. Folds Plus rams had higher food intakes than Folds Minus rams which may be a factor in their reduced heat tolerance.

Optimization of Data Center Room Layout to Minimize Rack Inlet Air Temperature

2006 ◽  
Vol 128 (4) ◽  
pp. 380-387 ◽  
Author(s):  
Siddharth Bhopte ◽  
Dereje Agonafer ◽  
Roger Schmidt ◽  
Bahgat Sammakia
Keyword(s):  
Air Temperature ◽  
Data Center ◽  
Floor Tile ◽  
Optimization Approach ◽  
Wrong Decision ◽  
Air Temperatures ◽  
Entire Height ◽  
Ceiling Height ◽  
Facility Manager ◽  
Heat Loads

In a typical raised floor data center with alternating hot and cold aisles, air enters the front of each rack over the entire height of the rack. Since the heat loads of data processing equipment continue to increase at a rapid rate, it is a challenge to maintain the temperature of all the racks within the stated requirement. A facility manager has discretion in deciding the data center room layout, but a wrong decision will eventually lead to equipment failure. There are many complex decisions to be made early in the design as the data center evolves. Challenges occur such as optimizing the raised floor plenum, floor tile placement, minimizing the data center local hot spots, etc. These adjustments in configuration affect rack inlet air temperatures, which is one of the important keys to effective thermal management. In this paper, a raised floor data center with 12kW racks is considered. There are four rows of racks with alternating hot and cold aisle arrangement. Each row has six racks installed. Two air-conditioning units supply chilled air to the data center through the pressurized plenum. Effect of plenum depth, floor tile placement, and ceiling height on the rack inlet air temperature is discussed. Plots will be presented over the defined range. A multivariable approach to optimize data center room layout to minimize the rack inlet air temperature is proposed. Significant improvement over the initial model is shown by using a multivariable design optimization approach.

scholarly journals Simulation of energy impact of an energy recovery ventilator in Northern housing

2021 ◽  
Vol 246 ◽  
pp. 10005
Author(s):  
Jing Li ◽  
Radu Zmeureanu ◽  
Hua Ge
Keyword(s):  
Air Temperature ◽  
Indoor Air ◽  
Energy Recovery ◽  
Energy Use ◽  
Energy Savings ◽  
Airflow Rate ◽  
Outdoor Air ◽  
Energy Impact ◽  
Core Energy ◽  
Air Intake

The single core Energy Recovery Ventilator (ERV) used in this study is equipped with defrost control that recirculates the exhaust indoor air, while keeps the outdoor air intake damper closed. This defrost strategy has the disadvantage of reducing the outdoor air supplied to the house, which may affect the indoor air quality. First, this paper presents new correlation-based models of supply air temperature T2 after the energy recovery core during normal and defrost operation modes based on laboratory experimental data. A pre-heating coil heats the supply air from T2 to indoor air temperature. Second, a house in Montreal (4356 HDD) is simulated as a reference using TRNSYS program. Since the program cannot simulate the operation under defrost mode, the new models are connected in TRNSYS using equation boxes. The energy use of houses at three locations in northern Canada with HDD of 8798 (Inuvik), 8888 (Kuujjuaq) and 12208 (Resolute), are also simulated, without and with ERV unit. The seasonal energy used for heating the house and pre-heating the supply air is compared with results from Montreal. Compared to the case without heat recovery, the ERV unit leads to energy savings: 24% (Montreal), 26% (Inuvik), 27% (Kuujjuaq), and 27% (Resolute). Compared to the minimum standard requirements, the outdoor airflow rate due to defrost is reduced by 4.7% (223 hours) in Montreal, 19% (1043 hours) in Inuvik, 13% (701 hours) in Kuujjuaq, and 24% (1379 hours) in Resolute.

scholarly journals Redesigning space layout by considering thermal comfort and prevention of COVID-19 transmission in campus building

2021 ◽  
Vol 881 (1) ◽  
pp. 012017
Author(s):  
Wenny Arminda ◽  
Widi Dwi Satria ◽  
Maqbul Kamaruddin ◽  
M. Shoful Ulum
Keyword(s):  
Air Temperature ◽  
Indoor Air ◽  
Disease Transmission ◽  
Teaching And Learning ◽  
Human Movement ◽  
Physical Contact ◽  
Concept Design ◽  
West Side ◽  
Air Temperatures ◽  
East West

Abstract Lecture building is one of the important facilities in supporting the success of the teaching and learning process. The lecture room should be thermally comfortable and has a low risk of disease transmission. In adapting to the Covid-19 pandemic, attention to prevent disease transmission is necessary to the safety of students and lecturers while staying on campus. This study aims to propose a new concept design related to the arrangement of indoor layouts that minimize the crowds and reducing indoor air temperatures due to exposure to solar radiation on the east-west side of the building. The research was conducted by observing human movement patterns and measuring indoor air temperature and surface façade temperature adjacent to the outside environment. The results obtained that the average indoor air temperature was in the range between 28.8 - 33.2 °C, with a surface temperature on the east-west side, reaching 39.1 °C. The new design proposed the concept of one-way access by separating vertical and horizontal circulation, additional corridors, and rearranging the layout of lecture rooms to distinguish in-out access to minimize contact physical contact between building users.

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