scholarly journals A radiative cooling structural material

Science ◽  
2019 ◽  
Vol 364 (6442) ◽  
pp. 760-763 ◽  
Author(s):  
Tian Li ◽  
Yao Zhai ◽  
Shuaiming He ◽  
Wentao Gan ◽  
Zhiyuan Wei ◽  
...  
Keyword(s):  
Structural Material ◽  
Air Conditioning ◽  
Energy Savings ◽  
Cellulose Nanofibers ◽  
Mid Infrared ◽  
Natural Wood ◽  
Infrared Wavelengths ◽  
Potential Impact ◽  
Dry Climates ◽  
Cooling Methods

Reducing human reliance on energy-inefficient cooling methods such as air conditioning would have a large impact on the global energy landscape. By a process of complete delignification and densification of wood, we developed a structural material with a mechanical strength of 404.3 megapascals, more than eight times that of natural wood. The cellulose nanofibers in our engineered material backscatter solar radiation and emit strongly in mid-infrared wavelengths, resulting in continuous subambient cooling during both day and night. We model the potential impact of our cooling wood and find energy savings between 20 and 60%, which is most pronounced in hot and dry climates.

scholarly journals Water Extraction from Air by Refrigeration—Experimental Results from an Integrated System Application

2018 ◽  
Vol 8 (11) ◽  
pp. 2262 ◽  
Author(s):  
Lucia Cattani ◽  
Anna Magrini ◽  
Paolo Cattani
Keyword(s):  
Drinking Water ◽  
Air Conditioning ◽  
Energy Savings ◽  
Integrated Design ◽  
Developed Countries ◽  
Integrated System ◽  
Domestic Water ◽  
Community Needs ◽  
Dry Climates ◽  
Air Conditioning Systems

Water is an indispensable resource for life. Several technologies have been studied and used in the past to extract water from the ground, the air or the sea. The technologies vary depending on community needs and resources. In developed countries, air conditioning systems are widespread, and the use of condensed water from air conditioning systems is of potential interest. In hot and dry climates, in arid regions where refrigeration processes represent a basic need for indoor comfort, advantages of an integrated design of HVAC (Heating, Ventilation and Air Conditioning) systems optimized for water production rather than for air treatment could be evaluated. In the current work, a real application, which embodies savings of both energy and drinking water, is presented. It represents an evolution of a previously studied integrated system to simultaneously provide air conditioning and water to a hotel. The main target of this system is to meet drinking water requirements and, secondly, to provide domestic water heating and primary air for a non-conditioned zone. Main features of the integrated system are outlined, the needs of the hotel are described, and calculations of water and energy savings are presented. Moreover, a simulation tool was developed with the aim to evaluate possible water savings in a one-year period and to improve the efficiency of the system. A method to verify the effectiveness of the integrated system is also described.

Assessment of the accuracy of scaling methods for radiance simulations at far and mid infrared wavelengths

2021 ◽  
pp. 107739
Author(s):  
Michele Martinazzo ◽  
Davide Magurno ◽  
William Cossich ◽  
Carmine Serio ◽  
Guido Masiello ◽  
...  
Keyword(s):  
Mid Infrared ◽  
Scaling Methods ◽  
Infrared Wavelengths

scholarly journals Proposal to Refine Solar Radiation of Typical Meteorological Year Database and Evaluation on the Influence of Air-Conditioning Load

Atmosphere ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 524
Author(s):  
Jihui Yuan ◽  
Kazuo Emura ◽  
Craig Farnham
Keyword(s):  
Solar Radiation ◽  
Air Conditioning ◽  
Energy Savings ◽  
Energy Resource ◽  
Global Solar Radiation ◽  
Resource Assessment ◽  
Weather Data ◽  
Diffuse Solar Radiation ◽  
Chinese Standard ◽  
The Impact

The Typical meteorological year (TMY) database is often used to calculate air-conditioning loads, and it directly affects the building energy savings design. Among four kinds of TMY databases in China—including Chinese Typical Year Weather (CTYW), International Weather for Energy Calculations (IWEC), Solar Wind Energy Resource Assessment (SWERA) and Chinese Standard Weather Data (CSWD)—only CSWD is measures solar radiation, and it is most used in China. However, the solar radiation of CSWD is a measured daily value, and its hourly value is separated by models. It is found that the cloud ratio (diffuse solar radiation divided by global solar radiation) of CSWD is not realistic in months of May, June and July while compared to the other sets of TMY databases. In order to obtain a more accurate cloud ratio of CSWD for air-conditioning load calculation, this study aims to propose a method of refining the cloud ratio of CSWD in Shanghai, China, using observed solar radiation and the Perez model which is a separation model of high accuracy. In addition, the impact of cloud ratio on air-conditioning load has also been discussed in this paper. It is shown that the cloud ratio can yield a significant impact on the air conditioning load.

scholarly journals AUDIT ENERGI PADA SEBUAH HOTEL

2012 ◽  
Vol 16 (3) ◽  
pp. 131
Author(s):  
Didik Ariwibowo
Keyword(s):  
Energy Consumption ◽  
Air Conditioning ◽  
Energy Savings ◽  
Electric Energy ◽  
Electrical Energy ◽  
Hot Water ◽  
Electrical Energy Consumption ◽  
Energy Audit ◽  
Electric Energy Consumption ◽  
Pumping System

Didik Ariwibowo, in this paper explain that energy audit activities conducted through several phases, namely: the initial audit, detailed audit, analysis of energy savings opportunities, and the proposed energy savings. Total energy consumed consists of electrical energy, fuel, and materials in this case is water. Electrical energy consumption data obtained from payment of electricity accounts for a year while consumption of fuel and water obtained from the payment of material procurement. From the calculation data, IKE hotels accounted for 420.867 kWh/m2.tahun, while the IKE standards for the hotel is 300 kWh/m2.tahun. Thus, IKE hotel included categorized wasteful in energy usage. The largest energy consumption on electric energy consumption. Largest electric energy consumption is on the air conditioning (AC-air conditioning) that is equal to 71.3%, and lighting and electrical equipment at 27.28%, and hot water supply system by 4.44%. Electrical energy consumption in AC looks very big. Ministry of Energy and Mineral Resources of the statutes, the profile of energy use by air conditioning at the hotel by 48.5%. With these considerations in the AC target for audit detail as the next phase of activity. The results of a detailed audit analysis to find an air conditioning system energy savings opportunities in pumping systems. Recommendations on these savings is the integration of automation on the pumping system and fan coil units (FCU). The principle of energy conservation in the pumping system is by installing variable speed drives (VSD) pump drive motor to adjust speed according to load on the FCU. Load variations FCU provide input on the VSD pumps to match. Adaptation is predicted pump can save electricity consumption up to 65.7%. Keywords: energy audit, IKE, AC

Design of a heat recovery unit using exhaust gases for energy savings in an absorption air conditioning unit

2021 ◽  
pp. 117031
Author(s):  
Mostafa El-Shafie ◽  
M. Khalil Bassiouny ◽  
Shinji Kambara ◽  
Samy M. El-Behery ◽  
A.A. Hussien
Keyword(s):  
Air Conditioning ◽  
Heat Recovery ◽  
Energy Savings ◽  
Exhaust Gases ◽  
Recovery Unit

Thermal performance assessment of cool roofs on supermarkets through case analysis in 13 cities

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Juan Carlos Ríos-Fernández
Keyword(s):  
Energy Consumption ◽  
Air Conditioning ◽  
Energy Savings ◽  
Real Data ◽  
Research Approach ◽  
Environmental Implications ◽  
Content Type ◽  
Cool Roof ◽  
Increase Energy Efficiency ◽  
Cool Roofs

PurposeThis paper aims to study the use of cool roof technology to avoid unnecessary energy consumption in supermarkets. This will allow to reduce and even cancel the heat absorbed by the roofs, transferring it to the buildings and thus, creating more sustainable cities.Design/methodology/approachThirteen real supermarkets with cool roofs were analysed in Australia, Canada, the USA and Spain. An analysis of so many supermarkets located in different parts of the world with different climatic zones has allowed an inductive analysis, obtaining real data of energy consumption associated with the air conditioning installations for a year with and without implementing the cool roof technology.FindingsThe paper provides insights on how the use of cool roof managed to reduce the need for energy for heating, ventilating and air conditioning by between 3.5 and 38%. Additionally, this technology reduces the annual generation of carbon dioxide (CO2) emissions per square meter of supermarket up to 2.7 kgCO2/m2. It could be an economical technology to apply in new and old buildings with a period of average economic recovery of four years.Research limitations/implicationsBecause of the chosen research approach, the research results may be generalisable. Therefore, researchers are encouraged to test proposals in construction with other uses.Practical implicationsThe paper includes economic and environmental implications for the development of cool roof technology and smooths the way for its implementation to increase energy efficiency in commercial buildings.Originality/valueThis paper is an innovative contribution to the application of cool roof technology as a source of energy savings in commercial construction through the analysis of supermarkets located in different countries with different climate zones. This will help other researchers to advance in this field and facilitate the implementation of the technology.

scholarly journals THERMAL COMFORT AND ENERGY SOLUTIONS FOR A BETTER RESIDENTIAL ENVIRONMENT IN MALAYSIA

2015 ◽  
Vol 13 (5) ◽  
Author(s):  
Noor Aziah Mohd Ariffin
Keyword(s):  
Thermal Comfort ◽  
Air Conditioning ◽  
Energy Savings ◽  
Energy Performance ◽  
Data Monitoring ◽  
Medium Density ◽  
Design Strategies ◽  
Residential Energy ◽  
Passive Design ◽  
Design Systems

In hot-humid Malaysia, there are around five million units of housing. Among these, the medium-density terraced are the most built. However, little emphasis was given to designing for thermal comfort and energy efficiency. Consequently, air-conditioning is ubiquitous with ever-rising residential energy consumption. This paper studied passive design systems to improve living conditions and conserve energy through orientation and insulation parameters for terraced housing. Utilizing a triangulation of methods to correlate between thermal comfort and energy performance, findings from the questionnaire survey, data monitoring and computer simulation contended that with the passive design strategies minimum thermal comfort is attainable and energy savings predicted.

Kerr nonlinearity and multi-photon absorption in germanium at mid-infrared wavelengths

2017 ◽  
Vol 111 (9) ◽  
pp. 091902 ◽  
Author(s):  
B.-U. Sohn ◽  
C. Monmeyran ◽  
L. C. Kimerling ◽  
A. M. Agarwal ◽  
D. T. H. Tan
Keyword(s):  
Kerr Nonlinearity ◽  
Photon Absorption ◽  
Mid Infrared ◽  
Infrared Wavelengths

The Analysis of Modifications in Cooling Systems for High-Performance Data Centers. A Case Study

2017 ◽  
Author(s):  
Artur Rusowicz ◽  
Adam Ruciński ◽  
Rafał Laskowski
Keyword(s):  
Air Conditioning ◽  
High Performance ◽  
Energy Savings ◽  
Cooling System ◽  
Capital Expenditure ◽  
Cooling Power ◽  
Power Demand ◽  
Excessive Heat ◽  
Refrigeration Equipment ◽  
Payback Time

One of main issues concerning server room operation is appropriate cooling of electronic modules to prevent excessive heat generation resulting in their damage. Since high cooling powers are required, precision air conditioning systems are used that are specially designed for cooling server and equipment rooms, server cabinets, etc. These devices require very large energy supplies. The paper proposes an upgrade of a cooling system for three server rooms in which refrigeration equipment with a cooling power of 1.873 MW is installed. The average actual cooling power demand is 890 kW, and some units work as a standby. Thir-eight direct-evaporation air-conditioning cabinets are installed. The refrigerant is R407C. The devices have been operated for 14 years; therefore, the refrigeration equipment should be replaced with modern units. The paper compares three approaches: replacing the units with similar ones based on newer technology, introducing contained aisle configurations of rack cabinets and units based on newer technology with additional EconoPhase modules. The application of free cooling was not analyzed since mounting additional heat exchangers was impossible (due to the lack of space and limited roof loading capacity). The paper provides capital and operating costs of the solutions. The introduction of up-to-date units and replacing condensers resulted in lowering the electric power demand by 16%. The simple payback time (SPBT) of this solution is 18.8 years. The energy savings achieved through the second solution (contained aisle configurations of rack cabinets) amount to 37.8%, with SPBT equal to 8.38 years. Variant III, consisting in using modern units with additional EconoPhase modules, significantly improves energy savings (48.3%) but it requires large capital expenditure, with simple payback time of 12.1 years.

scholarly journals Investigation of Separated Two-Phase Thermosiphon Loop for Relieving the Air-Conditioning Loading in Datacenter

Energies ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 105 ◽  
Author(s):  
Hafiz Daraghmeh ◽  
Mohammed Sulaiman ◽  
Kai-Shing Yang ◽  
Chi-Chuan Wang
Keyword(s):  
Temperature Distribution ◽  
Energy Saving ◽  
Air Conditioning ◽  
Energy Savings ◽  
Filling Ratio ◽  
Two Phase ◽  
System Pressure ◽  
Optimum Energy ◽  
Free Cooling ◽  
R 134A

This study investigates the feasibility of using R-134a filled separated two-phase thermosiphon loop (STPTL) as a free cooling technique in datacenters. Two data center racks one of them is attached with fin and tube thermosiphon were cooled by CRAC unit (computer room air conditioning unit) individually. Thermosiphon can help to partially eliminate the compressor loading of the CRAC; thus, energy saving potential of thermosiphon loop was investigated. The condenser is a water-cooled design and perfluoroalkoxy pipes were used as adiabatic riser/downcomer for easier installation and mobile capability. Tests were conducted with filling ratio ranging from 0 to 90%. The test results indicate that the energy saving increases with the rise of filling ratio and an optimum energy savings of 38.7% can be achieved at filling ratios of 70%, a further increase of filling ratio leads to a reduction in energy saving. At a low filling ratio like 10%, the evaporator starves for refrigerant and a very uneven air temperature distribution occurring at the exit of data rack. The uneven temperature distribution is relieved considerably when the evaporator is fully flooded. It is also found that the energy saving is in line with the rise of system pressure. Overfilling of the evaporator may lead to a decline of system pressure. A lower thermal resistance occurs at high filling ratios and higher ambient temperature.

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