Shifts in the hypothalamic temperature of rats acclimated to direct internal heat load with different schedules

Due to its significant role in improving indoor air quality, displacement ventilation system is widely adopted in current literature. This paper proposes a displacement ventilation system for room conditions with ceilings that are relatively low, internal heat load could be high, walls could be sunlit, and occupants doing the low physical activity. These conditions are prevalent in the Philippines, being a tropical country. Input parameters to the design process such as heat load, the height of the ceiling, comfort, and indoor air quality requirements were generated, and the main output parameters are the stratification height and ventilation airflow rate. To demonstrate the proposed displacement ventilation system, four cases were generated. Results show that the ventilation airflow rates obtained from the four cases were greater than the minimum outdoor air requirements for health in conference rooms and large assembly areas which are 17.5 and 3.5 liters/sec*person respectively, for smoking and no smoking rooms.

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A Comparison of the Relative Effectiveness of Fin Aspect Ratio Under Natural Convective Heat Transfer With Top Mounted Fins

Volume 9: Heat Transfer, Fluid Flows, and Thermal Systems, Parts A, B and C ◽

10.1115/imece2009-12364 ◽

2009 ◽

Author(s):

Anthony S. Pruszenski

Keyword(s):

Natural Convection ◽

Aspect Ratio ◽

Heat Load ◽

Relative Effectiveness ◽

Internal Heat ◽

Maximum Temperature ◽

Constant Heat ◽

Aspect Ratios ◽

Square Plate ◽

Base Width

Mechanical engineers often design fins on metal enclosures to dissipate an internal heat load using natural convection. This paper gives the results of a series of CFD (Computational Fluid Dynamics) studies, and, supporting calculations for the maximum temperature rise on a plate with a constant heat load of 100 watts applied to the bottom of the plate. Vertical fins are formed on the top surface of the plate. In this study, the horizontal dimensions and thickness of a square plate are held constant, while, the aspect ratio of the top surface fins are varied between studies. The aspect ratio is defined as the ratio of the height of the fin to the width of the base of the fin. The study compares aspect ratios from 1:1 to 40:1 with a constant base width. In addition, comparisons between 20:1 aspect ratio fins with the same height but with different fin counts due to changes in fin separation distances are compared. Closely spaced fins are not always the best solution for natural convection.

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Thermoregulation of juvenile grey seals, Halichoerus grypus, in air

Canadian Journal of Zoology ◽

10.1139/z96-025 ◽

1996 ◽

Vol 74 (2) ◽

pp. 201-208 ◽

Cited By ~ 13

Author(s):

Patrice Boily ◽

David M. Lavigne

Keyword(s):

Metabolic Rate ◽

Core Temperature ◽

Low Temperatures ◽

Heat Load ◽

Cold Water ◽

Internal Heat ◽

Ambient Air ◽

Halichoerus Grypus ◽

Metabolic Depression ◽

Air Temperatures

Metabolic rate, core temperature, and duration of sleep-related apnea events were monitored in three juvenile grey seals (Halichoerus grypus) aged 7–19 months (49–78 kg), at ambient air temperatures ranging from −18 °C to 35 °C. At low temperatures, only one seal increased its metabolic rate (at −18 °C), whereas at high temperatures (up to 35 °C) none of the three animals increased its metabolic rate. Nonetheless, seals usually became hyperthermic when they were subjected to air temperatures of 30 °C or higher. There was no indication that the duration of sleep-related apnea was greater at higher temperatures. The sleeping metabolic rate was significantly lower (20%) than the resting level. A metabolic depression associated with sleep may be advantageous at higher temperatures, reducing the internal heat load of the animal. These results suggest that cold-water adaptations of juvenile grey seals do not interfere with their ability to cope with higher air temperatures. Also, such animals should not be directly limited in their distribution by either high or low ambient air temperatures.

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ENERGY EFFICIENCY OF A VARIABLE SPEED OF THE CENTRALIZED AIR CONDITIONING SYSTEM USING PID CONTROLLER

Jurnal Teknologi ◽

10.11113/jt.v78.9586 ◽

2016 ◽

Vol 78 (8-4) ◽

Cited By ~ 2

Author(s):

Henry Nasution ◽

Afiq Aiman Dahlan ◽

Azhar Abdul Aziz ◽

Ulul Azmi ◽

Sumeru Sumeru ◽

...

Keyword(s):

Energy Consumption ◽

Thermal Comfort ◽

Pid Control ◽

Pid Controller ◽

Heat Load ◽

Air Conditioning ◽

Internal Heat ◽

Variable Speed ◽

Air Conditioning System ◽

Low Energy Consumption

PID control system for air-conditioning system in residence is presented in this manuscript. The control strategy is focused on low energy consumption and thermal comfort for indoor user. The algorithm is developed to control the compressor speed at an appropriate speed according to the temperature inside the controlled area using PID controller. Software is developed to measure and interface the system with controlling the system according to the algorithm. The temperature settings are 20, 22 and 24oC with internal heat load of 0 and 1000 Watt. The results obtained proved that the technique can lower the energy consumption and increased temperature control for better thermal comfort compared to on/off controller

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The Effect of Ambient Temperature on the Performance of Automotive Air-Conditioning System

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.819.221 ◽

2016 ◽

Vol 819 ◽

pp. 221-225 ◽

Cited By ~ 1

Author(s):

Hisamudin Mohd Yunus ◽

Henry Nasution ◽

Azhar Abdul Aziz ◽

Sumeru ◽

Afiq Aiman Dahlan

Keyword(s):

Ambient Temperature ◽

Heat Load ◽

Air Conditioning ◽

Engine Speed ◽

Internal Heat ◽

Experimental Period ◽

Coefficient Of Performance ◽

Air Conditioning System ◽

Automotive Air Conditioning ◽

Automotive Air Conditioning System

The automotive air conditioning is one of the important things to be discovered and analyses to maximize the coefficient of performance (COP). The effects of the global warming in a surrounding world give a big impact on performance of air conditioning system in the vehicle. The significant of these issues make the ambient temperature changing. The ambient temperature it’s different according to the type of the place. The different ambient temperature will effect on the performance of air conditioning system. This study will analysis the energy consumption, temperature distribution and COP at various ambient temperature (30, 35 and 40°C), internal heat load (0, 500,700 and 1000 W) and engine speed (1000, 1500 and 2000 rpm) using HFC-R134a as the refrigerant. Measurements were taken during the 30 minute experimental period for temperature set point which 21°C. The results showed that the performance of the automotive air conditioning system decreases when ambient temperature, internal heat load and compressor speed increased.

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