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.

The Optimum Energy Saving Measures for Retrofitting Residential Buildings

2016 ◽  
Vol 41 (1) ◽  
pp. 88-92
Author(s):  
Rong-Yue Zheng ◽  
Jian Yao
Keyword(s):  
Energy Saving ◽  
Energy Savings ◽  
Residential Buildings ◽  
Thermal Conditions ◽  
High Energy ◽  
Cold Winter ◽  
Efficiency Measures ◽  
Optimum Energy ◽  
Potential Energy Saving ◽  
Selection Of

A large number of residential buildings in hot summer and cold winter zone of China are non-energy efficient with poor indoor thermal conditions. Retrofitting residential buildings with energy efficiency measures is thus important for residents. However, this work progressed slowly because practically applicable measures that not only have high energy savings but also improve indoor thermal performance have not been studied. Thus, this paper carried out a simulation study on the selection of suitable energy saving measures for residential buildings in hot summer and cold winter zone of China. Five potential energy saving options are considered and the energy, indoor thermal comfort and economic performance are compared. The results show that adding movable solar shades is the optimum option with all performance indices ranking first. Meanwhile, this measure is also the only acceptable energy saving solution for residents since its payback period is less than the lifespan of a building. As a conclusion, it is recommended to use movable solar shades as a first priority when retrofitting residential buildings.

Analysis for Energy Savings Potential and Economics of Combined Air-Conditioning System with Temperature and Humidity Decoupled Treatment

2011 ◽  
Vol 280 ◽  
pp. 71-75
Author(s):  
Zhong Chao Zhao ◽  
Dong Hui Zhang ◽  
Yu Ping Chen
Keyword(s):  
Energy Consumption ◽  
Energy Saving ◽  
Air Conditioning ◽  
Energy Savings ◽  
Operating Cost ◽  
Air Conditioning System ◽  
Operation Mechanism ◽  
Energy Saving Potential ◽  
Temperature And Humidity

In this paper, the operation mechanism of combined air-conditioning system with temperature and humidity decoupled treatment (CACSTHDT) was presented, and the energy saving potential and economics of CACSTHDT were primarily analyzed through compared with a traditional air-conditioning system. The results indicated that CACSTHDT could save up to 28.64% energy consumption in comparison with a traditional air-conditioning system. The operating cost in one summer only was 71.36% of that cost of traditional air-conditioning system.

A Fuzzy Logic Based on Theoptimal Energy Conservation with Human Satisfaction of the Inverter Air Conditioning System for Tropical Area

2012 ◽  
Vol 622-623 ◽  
pp. 122-129
Author(s):  
Chutima Plodprong ◽  
Worarat Patprakorn ◽  
Pornrapeepat Bhasaputra
Keyword(s):  
Fuzzy Logic ◽  
Energy Saving ◽  
Air Conditioning ◽  
Energy Savings ◽  
Comfort Zone ◽  
Air Conditioning System ◽  
Logic Control ◽  
Matlab Program ◽  
Tropical Area ◽  
Fan Speed

This research is study of the air conditioning by used fuzzy logic control to analysis. It will take into account the energy savings and the room temperature remained in range of comfort zone for the resident's satisfaction. To control % AC compressor and fan speed. The system was simulated and designed simulation model of fuzzy logic controlled on Matlab program to monitor energy consumption and temperature of the room. The results indicate that thermal comfort of the room together with energy saving can be obtained through fuzzy logic controlled .At a temperature setting of 25 °C and defined heat load in the room, the energy saving for the system is calculated to 30.77 % for fuzzy controllers when compared with on-off condition.

Energy Saving in a Heat Pump Air-Conditioning System Using Liquid Desiccant and Membrane Contactors

2011 ◽  
Author(s):  
Stefano Bergero ◽  
Anna Chiari
Keyword(s):  
Energy Saving ◽  
Heat Pump ◽  
Hybrid System ◽  
Air Conditioning ◽  
Energy Savings ◽  
Climatic Conditions ◽  
Operating Conditions ◽  
Membrane Contactor ◽  
Traditional System ◽  
Vapour Compression

It has been demonstrated in the literature that significant energy savings can be achieved in air-conditioning through the use of so-called hybrid systems, in which a chemical dehumidification system is combined with a vapour-compression heat pump. The advantage of such systems lies in the fact that the heat pump can operate at a higher evaporation temperature than that of a traditional system in which dehumidification is achieved through condensation, thereby achieving higher coefficients of performance. The hybrid system described in the present paper operates as follows: the air supplied to the conditioned ambient is simultaneously cooled and dehumidified in an air-solution membrane contactor. The LiCl solution is cooled by means of a vapour-compression heat pump using the refrigerant KLEA 410A. The solution is regenerated in another membrane contactor by exploiting the exhaust air and the heat rejected by the condenser. A study of the steady-state behaviour of the system in summer climatic conditions was carried out, on varying some significant operating parameters, such as the thermal efficiency of the heat exchangers, the outdoor temperature and the sensible load of the conditioned room. The performances of the hybrid system were compared with those of a traditional direct-expansion air-conditioning plant; the results of the simulations reveal that, in particular operating conditions, energy saving can exceed 50%.

scholarly journals Hygrothermal study of dwelling submitted to passive cooling

2018 ◽  
Vol 22 (6 Part A) ◽  
pp. 2597-2604
Author(s):  
Razika Kharchi ◽  
Khaled Imessad
Keyword(s):  
Relative Humidity ◽  
Thermal Comfort ◽  
Air Conditioning ◽  
Natural Ventilation ◽  
Energy Savings ◽  
Pilot Project ◽  
Passive Cooling ◽  
Free Cooling ◽  
Air Conditioning Systems ◽  
Good Agreement

A significant portion of energy consumed in buildings is due to energy usage by heating, ventilation, and air conditioning systems. Free cooling is a good option for energy savings in the systems. In recent years, scientists, engineers, and architects designed successful and innovative buildings which use passive cooling techniques, such as natural ventilation. The house studied in the present work, is a pilot project undertaken jointly by the Centre for Development of Renewable Energies (CDER) and the National Centre for Studies and Research of the integrated building (CNERIB) in the framework of the MED-ENEC project (Mediterranean Energy Efficiency in Construction structure). The house under consideration has a surface area of 65 m2 and is located in the region of Algiers which characterized by a Mediterranean climate with relatively mild winters and a hot and humid summer. The aim of this work is to study the thermal comfort inside the house in summer without air conditioning systems, only ventilation is considered. The aim of this work is to study the effect of natural ventilation on both thermal and hygrometric comfort inside the house during the summer period. Numerical simulation is made using the TRNSYS software and the results obtained are in good agreement with measured values. The prototype home is designed in a way that natural ventilation allows thermal comfort which induced energy saving from air conditioning. The mean temperature measured in the interior of the house is 26?C. The relative humidity reaches about 70% in August. Thermal comfort is related to relative humidity that are the essential parameters of the feeling of comfort. Humidity is an important parameter in thermal comfort, it is why we can conclude that we have reached a relatively good hygrothermal comfort.

scholarly journals Analysis of the Energy Use in the Mexican Residential Sector by Using Two Approaches Regarding the Behavior of the Occupants

2018 ◽  
Vol 8 (11) ◽  
pp. 2136 ◽  
Author(s):  
Ivan Oropeza-Perez ◽  
Astrid Petzold-Rodriguez
Keyword(s):  
Sensitivity Analysis ◽  
Energy Saving ◽  
Air Conditioning ◽  
Energy Use ◽  
Energy Savings ◽  
Integrated Approach ◽  
Low Energy ◽  
Energy Devices ◽  
Residential Sector ◽  
Reliable Basis

An analysis of the energy use in the Mexican residential sector is carried out. To achieve this, two approaches are taken into account. The first one is the usage of low-energy devices, and the second one is the decrease of their time of use. These two approaches are considered in the calculation method with random values of power and time of usage. The energy activities are divided into air-conditioning, illumination & appliances, and refrigeration. After total annual use is validated with the actual values of energy use in 2015, a sensitivity analysis of the approaches used separately and together is carried out in order to determine the potential of energy saving. Thereby, it is found that the most influential parameter for energy saving is the extensive acquisition of more efficient technologies of illumination & appliances, followed by the decrease of use of the same illumination & appliances. Furthermore, with an integrated approach that takes into account both the use of efficient devices and the reduction of their use for the three energy activities, a maximum of 19.67 TWh is calculated in 2015 for the Mexican residential sector. This approach is therefore expected to have a reliable basis for the development and improvement of policies that help to drive energy savings in an extensive manner in Mexico.

scholarly journals LoBEMS—IoT for Building and Energy Management Systems

Electronics ◽  
2019 ◽  
Vol 8 (7) ◽  
pp. 763 ◽  
Author(s):  
Bruno Mataloto ◽  
Joao C. Ferreira ◽  
Nuno Cruz
Keyword(s):  
Energy Saving ◽  
Energy Management ◽  
Management System ◽  
Air Conditioning ◽  
Energy Savings ◽  
Environmental Data ◽  
Energy Management System ◽  
Energy Monitoring ◽  
Multiple Systems ◽  
Layered Architecture

This work presents the efforts on optimizing energy consumption by deploying an energy management system using the current IoT component/system/platform integration trends through a layered architecture. LoBEMS (LoRa Building and Energy Management System), the proposed platform, was built with the mindset of proving a common platform that would integrate multiple vendor locked-in systems together with custom sensor devices, providing critical data in order to improve overall building efficiency. The actions that led to the energy savings were implemented with a ruleset that would control the already installed air conditioning and lighting control systems. This approach was validated in a kindergarten school during a three-year period, resulting in a publicly available dataset that is useful for future and related research. The sensors that feed environmental data to the custom energy management system are composed by a set of battery operated sensors tied to a System on Chip with a LoRa communication interface. These sensors acquire environmental data such as temperature, humidity, luminosity, air quality but also motion. An already existing energy monitoring solution was also integrated. This flexible approach can easily be deployed to any building facility, including buildings with existing solutions, without requiring any remote automation facilities. The platform includes data visualization templates that create an overall dashboard, allowing management to identify actions that lead to savings using a set of pre-defined actions or even a manual mode if desired. The integration of the multiple systems (air-conditioning, lighting and energy monitoring) is a key differentiator of the proposed solution, especially when the top energy consumers for modern buildings are cooling and heating systems. As an outcome, the evaluation of the proposed platform resulted in a 20% energy saving based on these combined energy saving actions.

scholarly journals Carbon and Water Footprint of Energy Saving Options for the Air Conditioning of Electric Cabins at Industrial Sites

Energies ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3627 ◽  
Author(s):  
Santin ◽  
Chinese ◽  
Saro ◽  
De Angelis ◽  
Zugliano
Keyword(s):  
Energy Saving ◽  
Carbon Footprint ◽  
Energy Demand ◽  
Air Conditioning ◽  
Alternative Energy ◽  
Heat Dissipation ◽  
Water Footprint ◽  
Waste Heat ◽  
Cooling Towers ◽  
Free Cooling

Modern electric and electronic equipment in energy-intensive industries, including electric steelmaking plants, are often housed in outdoor cabins. In a similar manner as data centres, such installations must be air conditioned to remove excess heat and to avoid damage to electric components. Cooling systems generally display a water–energy nexus behaviour, mainly depending on associated heat dissipation systems. Hence, it is desirable to identify configurations achieving both water and energy savings for such installations. This paper compares two alternative energy-saving configurations for air conditioning electric cabins at steelmaking sites—that is, an absorption cooling based system exploiting industrial waste heat, and an airside free-cooling-based system—against the traditional configuration. All systems were combined with either dry coolers or cooling towers for heat dissipation. We calculated water and carbon footprint indicators, primary energy demand and economic indicators by building a TRNSYS simulation model of the systems and applying it to 16 worldwide ASHRAE climate zones. In nearly all conditions, waste-heat recovery-based solutions were found to outperform both the baseline and the proposed free-cooling solution regarding energy demand and carbon footprint. When cooling towers were used, free cooling was a better option in terms water footprint in cold climates.

Installation Design and Energy Conservation Analysis of Floor Radiant Cooling/Heating System with Solar Energy

2012 ◽  
Vol 594-597 ◽  
pp. 2146-2153 ◽  
Author(s):  
Qi Fen Li ◽  
Tao Li ◽  
Wei Dong Sun ◽  
Zhi Tian Zhou ◽  
Cui Cui Pan ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Energy Saving ◽  
Air Conditioning ◽  
Energy Savings ◽  
Heating System ◽  
High Energy ◽  
Primary Energy ◽  
Energy Saving Potential ◽  
Radiant Cooling ◽  
New Energy

How to reduce the energy consumption of air conditioning, to use new energy such as solar appropriately, and to achieve energy savings, are the problems must be treated in HVAC industry. Because of the high energy consumption of traditional air-conditioning and the need for reduction of emission, an air conditioning system (utilizing solar dehumidifying applied to heating/cooling radiant floor) is designed and installed in this paper. At the same time, as an example, the energy saving potential of system is analyzed. This type of heating/cooling radiant floor system is worth promoted if solve the dehumidification properly. By separating to deal with heat and moisture can reduce the energy-cost of traditional air-conditioning, and to achieve purposes of primary energy saving.

Thermal Comfort Characteristics Analysis of Induced Radiation Units

2013 ◽  
Vol 316-317 ◽  
pp. 1101-1105
Author(s):  
Ming Ming Sun ◽  
Jian Fa Zhong ◽  
Wei Jun Wu ◽  
Jian Liu ◽  
Zhi Yi Wang
Keyword(s):  
Temperature Distribution ◽  
Thermal Comfort ◽  
Energy Saving ◽  
Evaluation System ◽  
Air Conditioning ◽  
Air Conditioning System ◽  
Energy Saving Potential ◽  
Air Supply ◽  
Characteristics Analysis ◽  
Data Collation

Induces the operating principle of the induced radiation unit and studies the uniformity of indoor temperature distribution in the space and time, comfort and dewing condensation based on the PMV-PPD thermal comfort evaluation system. Through data collation and results analysis, obtains thermal comfort superiority and energy-saving potential of the reduced radiation air conditioning. The results show that the temperature distribution in the room stalled by the reduced radiation units is uniform, without sense of temperature difference and ventilation, providing an ultra-comfortable environment and that the indoor setting temperature can be up to 27°C on the premise of meeting comfort requirement. At the same time, air supply of low temperature can be achieved without condensation, reflecting the energy-saving potential of the system. These provide a reference for design of the induced radiation air conditioning system and further study.

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