Retrofitting low-cost heating ventilation and air-conditioning systems for energy management in buildings

2019 ◽  
Vol 236 ◽  
pp. 648-661 ◽  
Author(s):  
Syed Aftab Rashid ◽  
Zeeshan Haider ◽  
S.M. Chapal Hossain ◽  
Kashan Memon ◽  
Fazil Panhwar ◽  
...  
Keyword(s):  
Energy Management ◽  
Air Conditioning ◽  
Low Cost ◽  
Air Conditioning Systems

Significance of Temperature and Humidity Control for Agricultural Products Storage: Overview of Conventional and Advanced Options

2019 ◽  
Vol 15 (10) ◽  
Author(s):  
Muhammad Hamid Mahmood ◽  
Muhammad Sultan ◽  
Takahiko Miyazaki
Keyword(s):  
Air Conditioning ◽  
Low Cost ◽  
Freezing Temperature ◽  
Storage Life ◽  
Agricultural Products ◽  
Ambient Conditions ◽  
Humidity Control ◽  
Temperature And Humidity ◽  
Air Conditioning Systems ◽  
Term Storage

AbstractThe agricultural products are perishable in nature and possesses short shelf/storage life under ambient conditions. The temperature and humidity control systems are required to enhance to storage life of the products with optimum quality, quantity and nutritive attributes. In this regard, the significance of air-conditioning in storage application is highlighted along with the conventional storage options. The implications of compressor-based refrigeration and air-conditioning systems regarding low-cost and energy efficient air-conditioning systems are discussed in detailed. It is concluded that thermally driven air-conditioning systems can be used on top priority for the short-term storage of fresh agricultural products. Moreover, the long-term storage of products at freezing temperature can be made through hybrid systems instead of standalone conventional compressor based vapor compression refrigeration and/or air-conditioning systems. Finally, the air-conditioning systems are proposed for the optimum storage of different categorize of the food products.

scholarly journals Reducing Virus Transmission from Heating, Ventilation, and Air Conditioning Systems of Urban Subways

2021 ◽  
Author(s):  
Ata Nazari ◽  
Jiarong Hong ◽  
Farzad Taghizadeh-Hesary ◽  
Farhad Taghizadeh-Hesary
Keyword(s):  
Air Conditioning ◽  
Low Cost ◽  
Infected Individual ◽  
Virus Transmission ◽  
Mean Value ◽  
Hvac System ◽  
Transit System ◽  
Encounter Probability ◽  
Flow Effects ◽  
Air Conditioning Systems

Abstract Transmission via virus-carrying aerosols inside enclosed spaces is an important transmission mode for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), as supported by growing evidence. The urban subway is one of the most commonly used enclosed spaces. The subway is a utilitarian and low-cost transit system in today’s society. However, studies are yet to demonstrate patterns of viral transmission in subway heating, ventilation, and air conditioning (HVAC) systems. To fill this gap, we performed a computational investigation of the airflow (and the associated aerosol transmission) in an urban subway cabin equipped with an HVAC system. We employed a transport equation for aerosol concentration, which was added to the basic buoyant solver to resolve aerosol transmission inside the subway cabin. This was achieved by considering the thermal, turbulence, and induced ventilation flow effects. Using the aerosol encounter probability over sampling lines crossing the passenger breathing zones, we can detect the highest infection risk zones inside the urban subway under different settings. We proposed a novel HVAC system that can impede aerosol spread, both vertically and horizontally, inside the cabin. In the conventional model, the maximum aerosol encounter probability from an infected individual breathing near the fresh-air ducts was equal to 15%. This decreased to 0.36% in the proposed HVAC model. Overall, using the proposed HVAC system for urban subways decreased the mean value of the aerosol encounter probability by approximately 79% compared to that for the conventional system.

Thermal Analysis of Low-Cost Dwellings in Mexico Using Greenroofs

2011 ◽  
Author(s):  
Mari´a G. Alpuche ◽  
Irene Marincic ◽  
Jose´ M. Ochoa ◽  
Hugo C. Moreno ◽  
Paloma Giottonini
Keyword(s):  
Energy Consumption ◽  
Air Conditioning ◽  
Low Cost ◽  
Concrete Block ◽  
Building Envelope ◽  
Air Cooling ◽  
Design Strategies ◽  
Cooling Systems ◽  
Air Conditioning Systems ◽  
Electricity Energy Consumption

According to the National Energy Balance (1), the electricity consumption in the residential and commercial sector represents thirty-three percent of the total consumed in the country. Most of the energy is consumed during the summer, when it is necessary to use air conditioning to maintain comfort conditions inside buildings. This aspect takes relevance in warm-dry climates, where a deficient design of building envelope and a wrong location of windows can increase the thermal loads producing an extra load to air conditioning systems and high costs by electricity energy consumption. For this reason, adequate design strategies and thermodynamic concepts have to be applied in order to make dwellings comfortable. Two dwellings are simulated and analyzed, the first one is made of regional materials like traditional concrete block walls, reinforced concrete roofs and economic finishes, the second one is proposed with a green roof and insulation in walls. The heat gains through the different constructive elements have been obtained, to analyze their impact on global thermal comfort and the electricity energy consumption of air cooling systems. Also, an exergy analysis has been applied to analyze exergy efficiency of air cooling systems and the influence that the building envelope can have in them with the proposed changes. The minimum exergy expenditure of air conditioning systems required to achieve comfort conditions inside dwellings could be a useful benchmark for the comparison of various dwelling designs.

ANALYSIS OF COMPETING VARIANTS OF AIR CONDITIONING SYSTEMS WITHOUT AIR EXTRACTION FROM ENGINES AT THE STAGE OF PASSENGER AIRCRAFT ONBOARD SYSTEMS CONCEPTUAL DESIGN

2019 ◽  
Vol 6 (3) ◽  
pp. 80-85
Author(s):  
Denis Igorevich Smagin ◽  
Konstantin Igorevich Starostin ◽  
Roman Sergeevich Savelyev ◽  
Anatoly Anatolyevich Satin ◽  
Anastasiya Romanovna Neveshkina ◽  
...  
Keyword(s):  
Conceptual Design ◽  
Air Conditioning ◽  
Research University ◽  
Cooling System ◽  
Fuel Efficiency ◽  
Air Cooling ◽  
Moscow Aviation Institute ◽  
Air Conditioning System ◽  
Low Efficiency ◽  
Air Conditioning Systems

One of the ways to achieve safety and comfort is to improve on-board air conditioning systems.The use of air cooling machine determines the air pressure high level at the point of selection from the aircraft engine compressor. Because of the aircraft operation in different modes and especially in the modes of small gas engines, deliberately high stages of selection have to be used for ensuring proper operation of the refrigeration machine in the modes of the aircraft small gas engines. Into force of this, most modes of aircraft operation have to throttle the pressure of the selected stage of selection, which, together with the low efficiency of the air cycle cooling system, makes the currently used air conditioning systems energy inefficient.A key feature of the architecture without air extraction from the main engines compressors is the use of electric drive compressors as a source of compressed air.A comparative analysis of competing variants of on-board air conditioning system without air extraction from engines for longrange aircraft projects was performed at the Moscow Aviation Institute (National Research University).The article deals with the main approaches to the decision-making process on the appearance of a promising aircraft on-board air conditioning system at the stage of its conceptual design and formulated the basic requirements for the structure of a complex criterion at different life cycle stages.The level of technical and technological risk, together with a larger installation weight, will require significant costs for development, testing, debugging and subsequent implementation, but at the same time on-board air conditioning system scheme without air extraction from the engines will achieve a significant increase in fuel efficiency at the level of the entire aircraft.

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