Influence of ambient forced-air ventilation rate on potato storage wastage

1990 ◽  
Vol 33 (4) ◽  
pp. 433-440 ◽  
Author(s):  
P. Bertolini ◽  
A. Guarnieri
Keyword(s):  
Ventilation Rate ◽  
Potato Storage ◽  
Air Ventilation ◽  
Forced Air

scholarly journals Enhancing Air Quality for Embedded Hospital Germicidal Lamps

2021 ◽  
Vol 13 (4) ◽  
pp. 2389
Author(s):  
Jung-Shun Chen
Keyword(s):  
Air Quality ◽  
Hospital Staff ◽  
Ventilation Rate ◽  
Hospital Environment ◽  
Design Stage ◽  
Flow Noise ◽  
Air Ventilation ◽  
Air Disinfection ◽  
Type 3

The indoor air of a hospital is always full of bacteria and viruses due to patients with different diseases. These bacteria and viruses could be highly infectious to the people in the hospital irrespective of their health conditions, and could be hazardous to the patients, their care takers, and hospital staff. Thus, keeping a good hospital air quality is very essential to the operation of the hospital. This study aims at enhancing ventilation of the interior lighting of hospitals with germicidal capabilities. Air disinfection is accomplished by adding the specially designed disinfecting filters and fans to existing embedded lamps in the hospitals. The embedded lamp has a square shape of 601 mm in width and 112 mm in thickness. In the design stage, the air flow inside the embedded lamp with the added filters and fans was investigated by numerical simulation using a computational fluid dynamics (CFD) tool. Three designs, referred to as Types 1, 2, and 3, were evaluated using steady-state CFD flow simulations. The ventilation rate of the Type 1 design was about 251.9 CMH, and 348.3 CMH for the Type 2 design by increasing the fan outlet area. However, even though the ventilation was increased by 34%, the flow field of the Type 2 design was not uniform, resulting in flows being circulated around the side locations. Thus, the Type 3 design further treats this aspect by streamlining the outlet geometry and adding flow guiding vanes to reduce flow resistance and flow unsteadiness; the corresponding air ventilation rate reached 376.3 CMH. Hence, the Type 3 design was fabricated and tested. The test results confirm that the design not only has a higher ventilation rate but also operates under a smaller pressure drop, thus accomplishing the goal of providing good air quality in the hospital environment efficiently. Moreover, the associated flow noise is reduced by about 8 dBA. Hence, both an increase in the air ventilation rate and a reduction of noise are achieved simultaneously by the present method.

Thermal analysis of forced-air and thermosyphon cooling systems for the Inuvik airport expansion

1991 ◽  
Vol 28 (3) ◽  
pp. 399-409 ◽  
Author(s):  
L. B. Smith ◽  
J. P. Graham ◽  
J. F. Nixon ◽  
A. S. Washuta
Keyword(s):  
Thermal Analysis ◽  
Natural Convection ◽  
Key Words ◽  
Thermal Analyses ◽  
Cooling Systems ◽  
Air Ventilation ◽  
Forced Air ◽  
Department Of National Defence ◽  
Raft Foundations ◽  
National Defence

This paper presents a description of thermal analyses of forced-air ventilation and thermosyphon cooling systems, which were carried out in connection with the design of the concrete raft foundations that support hangars and other major structures to be constructed by the Department of National Defence adjacent to the existing airport near Inuvik, N.W.T. The cooling systems are required to prevent heat from the buildings from thawing the ice-rich permafrost present below the site. The analyses identified those parameters that have the most significant effect on the efficiency of each system. Based partially on the results of the analyses, it was decided to utilize air ventilation for cooling. The system is expected to perform satisfactorily under natural convection; however, the design includes a provision to install air blowers, if this should prove necessary in the future. A number of areas in which further research appears useful have been identified. Key words: permafrost, thermal analysis, raft foundation, hangar, ventilated slab, natural convection, thermosyphons.

First Canadian Geotechnical Colloquium: Foundation design approaches in permafrost areas

1978 ◽  
Vol 15 (1) ◽  
pp. 96-112 ◽  
Author(s):  
J. F. Nixon
Keyword(s):  
Influence Factors ◽  
Frozen Soil ◽  
Case Histories ◽  
Foundation Design ◽  
Large Structures ◽  
Theoretical Predictions ◽  
Air Ventilation ◽  
Insulation Thickness ◽  
Forced Air

The design of foundations in permafrost areas for large structures involves a knowledge of the thermal and mechanical properties of frozen soil. Recent creep data for frozen soils and ice are reviewed and some secondary (steady) creep relationships are established. A design approach for pile foundations in ice-rich permafrost is proposed and compared with available field case histories. The theory is found to provide reasonable predictions of pile settlements under load. It is suggested that the limitation of long-term pile settlements will control the design loadings.The thermal aspects of ventilated pad foundations are discussed and design curves are given for required pad and insulation thickness and ventilation capacity. Case histories indicate that in order to obtain the necessary ventilation capacity, forced air ventilation using electric fans is required for most practical situations.A settlement analysis for spread footings on permafrost is established and influence factors for settlement rate are given. Again it is apparent that allowable footing loads will be controlled by limiting long-term settlements, rather than by consideration of soil shear strength alone. Field data on the creep response of a tunnel in Fairbanks provide good correlation with theoretical predictions.

scholarly journals Reducing patients’ exposures to asthma and allergy triggers in their homes: an evaluation of effectiveness of grades of forced air ventilation filters

2014 ◽  
Vol 51 (6) ◽  
pp. 585-594 ◽  
Author(s):  
Kathleen Ward Brown ◽  
Taeko Minegishi ◽  
Joseph G. Allen ◽  
John F. McCarthy ◽  
John D. Spengler ◽  
...  
Keyword(s):  
Air Ventilation ◽  
Asthma And Allergy ◽  
Forced Air

Simulation and Analysis of a Secondary HVAC System Using MATLAB/SIMULINK Platform

2004 ◽  
Author(s):  
Paulo Rogerio Novak ◽  
Nathan Mendes ◽  
Gustavo Henrique da Costa Oliveira
Keyword(s):  
Computer Code ◽  
Ventilation Rate ◽  
Secondary System ◽  
Matlab Simulink ◽  
Loop Control ◽  
Hygrothermal Behavior ◽  
Rate Effects ◽  
Air Ventilation ◽  
And Performance ◽  
Cooling Coil

In this paper, the mathematical model of a secondary system (fan-coil) of a HVAC equipment is described. This system was inserted into a computer code developed in Matlab/Simulink platform devoted to the analysis of buildings hygrothermal behavior and performance of closed-loop control systems. The model is presented in terms of state-space variables that represent the energy and mass balance for each component of the fan-coil. Results are presented in terms of a comparative analysis of the cooling coil temperature and external air ventilation rate effects on the room air psychrometrics state. Finally, the control system performance is presented for both temperature and relative humidity.

DEVELOPMENT OF ADAPTIVE VENTILATION IN MULTIFUNCTIONAL LARGE-SCALE SPACE OF PUBLIC BUILDINGS

2021 ◽  
pp. 19-29
Author(s):  
Виталий Владимирович Шичкин ◽  
Мария Николаевна Жерлыкина ◽  
Сергей Анатольевич Яременко ◽  
Сергей Анатольевич Соловьев
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Large Scale ◽  
Numerical Study ◽  
Ventilation System ◽  
Public Buildings ◽  
Air Conditioners ◽  
Advantages And Disadvantages ◽  
Air Ventilation ◽  
Forced Air

Проанализирована актуальность строительства объектов культурно-массового назначения. Описана целесообразность проектирования многофункциональных трансформируемых помещений для общественных зданий. Приведены достоинства и недостатки применения рециркуляции воздуха как способа энергосбережения. Акцентировано внимание на поддержании чистоты воздуха в помещении и способах борьбы с бактериями и вирусами в приточном воздухе. Предложена схема многозональной общеобменной вентиляции воздуха без рециркуляции с блокированием кондиционеров для взаимозаменяемости с целью обеспечения микроклимата в многофункциональных помещениях общественных зданий. Описана последовательность работы системы вентиляции в теплый и холодный период года. Разработана система рекуперации с промежуточным холодоносителем для теплого периода года. Приведено описание работы установки кондиционирования воздуха. На примере реально существующего объекта выполнено численное исследование режимов работы системы вентиляции с рекуперацией теплоты и холода для трансформируемого помещения. Построен график для определения граничных условий работы рекуператора исходя из соотношения между интенсивностью теплообмена за счёт конвекции и интенсивностью теплообмена за счёт теплопроводности. При различных наружных температурах воздуха и расчетных температурах уходящего воздуха построены графики определения оптимальных параметров температуры воздуха на входе в утилизатор при оптимальных значениях водяного эквивалента . Выявлены и описаны режимы работы кондиционеров с теплоутилизатором в теплый период года, работающих в составе многозональной общеобменной вентиляции воздуха с блокированием кондиционеров для взаимозаменяемости. В ходе численного исследования выявлено, что наибольшая энергоэффективность системы вентиляции с рекуператором будет достигнута при принятии в качестве оптимального значения водяного эквивалента W = 3. We analyzed the relevance of cultural facilities construction. As well, we described the expediency of designing multifunctional transformable spaces for public buildings. Moreover we presented advantages and disadvantages of using air recirculation as a method of energy saving. A special attention is focused on maintaining indoor air clean and on various ways of combatting bacteria and viruses in the intake air. We offered a scheme of multi-zone forced air ventilation without recirculation with blocking air conditioners for interchangeability in order to provide a microclimate in multifunctional spaces of public buildings. We described the sequence of operations in the ventilation system in warm and cold seasons. We also developed a recuperation system with an intermediate refrigerant for warm seasons. The article presents a detailed description of the air conditioning unit operation. We carried out a numerical study of the operating modes of the ventilation system with heat and cold recovery for transformable spaces on the example of a real-existing facility. We show a graph to determine the boundary conditions of the recuperator operation based on the ratio between the intensity of heat transfer due to convection and the intensity of heat transfer due to thermal conductivity. At various outside air temperatures and design temperatures of the outgoing air, we created some graphs for determining the optimal parameters of the air temperature at the inlet to the heat exchanger at the optimal values of the water equivalent. We identified and described several modes of operation of air conditioners with a heat exchanger in warm seasons, operating as part of a multi-zone forced air ventilation with blocking air conditioners for interchangeability. In the course of a numerical study, it was revealed that the highest energy efficiency of a ventilation system with a recuperator could be achieved when the water equivalent value W = 3 is taken as the optimal value.

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