scholarly journals Retrofitting Inefficient Rooftop Air-Conditioning Units Reduces U.S. Navy Energy Use (Fact Sheet)

2014 ◽  
Author(s):  
Not Given Author
2018 ◽  
Vol 40 (2) ◽  
pp. 220-236 ◽  
Author(s):  
Irfan Ahmad Gondal

This study presents an innovative concept of a compact integrated solar-thermoelectric module that can form part of the building envelope. The heating/cooling modes use the photovoltaic electrical current to power the heat pump. The experimental analysis was carried out and the results of coefficient of performance were in the range 0.5–1 and 2.6–5 for cooling and heating functions, respectively. The study demonstrates that thermoelectric cooler can effectively be used for heating, ventilation, and air conditioning applications by integrating with solar panels especially in cooling applications. The system is environmentally friendly and can contribute in the implementation of zero energy buildings concept. Practical application: In order to help address the challenge of climate change and associated environmental effects, there is continuous demand for new technologies and applications that can be readily integrated into day-to-day life as a means of reducing anthropogenic impact. Heating, ventilation, and air conditioning, as one of the largest energy consumers in buildings, is the focus of many researchers seeking to reduce building energy use and environmental impact. This article proposes using facades and windows that have an integrated modules of solar photovoltaic cells and thermoelectric devices that are able to work together to achieve heating and cooling effects as required by the building without requiring any external operational power.


2020 ◽  
Vol 15 (7) ◽  
pp. 075006 ◽  
Author(s):  
Vincent Viguié ◽  
Aude Lemonsu ◽  
Stéphane Hallegatte ◽  
Anne-Lise Beaulant ◽  
Colette Marchadier ◽  
...  

Author(s):  
Milton Meckler

What does remain a growing concern for many users of Data Centers is their continuing availability following the explosive growth of internet services in recent years, The recent maximizing of Data Center IT virtualization investments has resulted in improving the consolidation of prior (under utilized) server and cabling resources resulting in higher overall facility utilization and IT capacity. It has also resulted in excessive levels of equipment heat release, e.g. high energy (i.e. blade type) servers and telecommunication equipment, that challenge central and distributed air conditioning systems delivering air via raised floor or overhead to rack mounted servers arranged in alternate facing cold and hot isles (in some cases reaching 30 kW/rack or 300 W/ft2) and returning via end of isle or separated room CRAC units, which are often found to fight each other, contributing to excessive energy use. Under those circumstances, hybrid, indirect liquid cooling facilities are often required to augment above referenced air conditioning systems in order to prevent overheating and degradation of mission critical IT equipment to maintain rack mounted subject rack mounted server equipment to continue to operate available within ASHRAE TC 9.9 prescribed task psychometric limits and IT manufacturers specifications, beyond which their operational reliability cannot be assured. Recent interest in new web-based software and secure cloud computing is expected to further accelerate the growth of Data Centers which according to a recent study, the estimated number of U.S. Data Centers in 2006 consumed approximately 61 billion kWh of electricity. Computer servers and supporting power infrastructure for the Internet are estimated to represent 1.5% of all electricity generated which along with aggregated IT and communications, including PC’s in current use have also been estimated to emit 2% of global carbon emissions. Therefore the projected eco-footprint of Data Centers into the future has now become a matter of growing concern. Accordingly our paper will focus on how best to improve the energy utilization of fossil fuels that are used to power Data Centers, the energy efficiency of related auxiliary cooling and power infrastructures, so as to reduce their eco-footprint and GHG emissions to sustainable levels as soon as possible. To this end, we plan to demonstrate significant comparative savings in annual energy use and reduction in associated annual GHG emissions by employing a on-site cogeneration system (in lieu of current reliance on remote electric power generation systems), introducing use of energy efficient outside air (OSA) desiccant assisted pre-conditioners to maintain either Class1, Class 2 and NEBS indoor air dew-points, as needed, when operated with modified existing (sensible only cooling and distributed air conditioning and chiller systems) thereby eliminating need for CRAC integral unit humidity controls while achieving a estimated 60 to 80% (virtualized) reduction in the number servers within a existing (hypothetical post-consolidation) 3.5 MW demand Data Center located in southeastern (and/or southern) U.S., coastal Puerto Rico, or Brazil characterized by three (3) representative microclimates ranging from moderate to high seasonal outside air (OSA) coincident design humidity and temperature.


2019 ◽  
Vol 11 (15) ◽  
pp. 4180 ◽  
Author(s):  
Carolina Rodriguez ◽  
María Coronado ◽  
Marta D’Alessandro ◽  
Juan Medina

Thermal comfort in the built environment is one of the most defining parameters influencing energy use, environmental quality, and occupant satisfaction. Unfortunately, there is a lack of research in this area within developing countries, which are becoming increasingly urbanised and where mechanical air conditioning demands are rising. Many of these countries are adopting thermal comfort standards such as the ASHRAE Standard 55, the EN 15251, and the ISO 7730 to regulate the use of air-conditioning; even when these standards have been widely criticised for their inadequacy within geographical regions different to the ones that they were designed for. Research suggests the need to confirm these models through further post-occupancy studies and fieldwork. Deficiencies in data collection and methodologies are thought to require particular attention to develop algorithms that can predict thermal comfort levels accurately. Comprehensive strategies considering interrelated psychological, physiological and social factors are needed. This manuscript highlights gaps of research, specifically within tropical developing countries, through the analysis of Colombia as a case study. It emphasises the importance of standardised fieldwork data and gives examples of alternative collection systems. This aims to contribute to the understanding of occupant´s adaptive behaviours and their impact on the mitigation of climate change.


2014 ◽  
Vol 6 (4) ◽  
pp. 207-238 ◽  
Author(s):  
Lucas W. Davis ◽  
Alan Fuchs ◽  
Paul Gertler

This paper evaluates a large-scale appliance replacement program in Mexico that from 2009 to 2012 helped 1.9 million households replace their old refrigerators and air conditioners with energy-efficient models. Using household-level billing records from  the universe of Mexican residential customers, we find that refrigerator replacement reduces electricity consumption by 8 percent, about one-quarter of what was predicted by ex ante analyses. Moreover, we find that air conditioning replacement actually increases electricity consumption. Overall, we find that the program is an expensive way to reduce externalities from energy use, reducing carbon dioxide emissions at a program cost of over $500 per ton. (JEL L68, L94, O12, O13, Q41, Q54)


EDIS ◽  
2009 ◽  
Vol 2009 (3) ◽  
Author(s):  
Marian Marinescu ◽  
Todd Bush

FOR-207, a 4-page illustrated fact sheet by Marian Marinescu and Todd Bush, is part of the Wood to Energy series. It introduces the use of wood pellets as a renewable energy source — current and new feedstock sources, feasibility, and research needs. Includes references. Published by the UF School of Forest Resources and Conservation, February 2009.


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