scholarly journals A Mathematical Tightening of Instantaneous Indoor and Outdoor Dry-Bulb and Wet-Bulb Temperature Tolerances

Energies ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1436
Author(s):  
Xinhao Hu ◽  
Zhongbin Zhang ◽  
Dandan Cai
Keyword(s):  
Energy Efficiency ◽  
Working Conditions ◽  
Information Criterion ◽  
Cooling Capacity ◽  
National Standard ◽  
Performance Tests ◽  
Air Conditioner ◽  
Chinese Room ◽  
Energy Efficiency Evaluation ◽  
Indoor And Outdoor

To reduce the inaccuracy in energy efficiency evaluation, indoor and outdoor dry-bulb and wet-bulb temperature (D&WBT) tolerances in the currently enacted Chinese room air conditioner (RAC) national standard were tightened into narrower intervals in this investigation. Characteristics of cooling capacity (CC) and energy efficiency ratio (EER) changing with D&WBTs were analyzed based on performance tests. AICc (corrected Akaike Information Criterion) was applied to determine the best fitted 3D curve equations of CC and EER to find the intervals of gradient extrema of CC and EER. The corresponding intervals of indoor and outdoor D&WBTs were concluded as the tightened D&WBT tolerances. For illustration, based on the performance tests of 154 working conditions, the instantaneous indoor and outdoor D&WBT tolerances in nominal refrigerating working conditions were respectively tightened from the original ±0.5/±0.3 °C into ±0.3/±0.2 °C (indoor tolerances) and ±0.4/±0.3 °C (outdoor tolerances). EER variation rate thus decreased from 2.11% to 1.03% (indoor) and 2.11% to 1.25% (outdoor).

scholarly journals Performance of Air Conditioning Unit under Constant Outdoor Wet-Bulb Temperature and Varied Dry-Bulb Temperature

2021 ◽  
Vol 39 (5) ◽  
pp. 1483-1490
Author(s):  
Andriyanto Setyawan ◽  
Susilawati Susilawati ◽  
Tandi Sutandi ◽  
Hafid Najmudin
Keyword(s):  
Energy Efficiency ◽  
Air Temperature ◽  
Air Conditioning ◽  
Cooling Capacity ◽  
Air Conditioner ◽  
Outdoor Air ◽  
Efficiency Ratio ◽  
Liquid Line ◽  
Discharge Temperature ◽  
Line Temperature

An experiment has been carried out for examining the performance of an air conditioning unit under constant outdoor wet-bulb temperature and varied dry-bulb temperature. During the experiment, the wet-bulb temperature of the compartment for outdoor unit was maintained at 22℃ and the dry-bulb temperature was varied from 24℃ to 36℃. The increase of outdoor air temperature results in the increase of supply air temperature, discharge temperature, suction temperature, and liquid line temperature. These cause the degradation of the air conditioner performance. An increase of power consumption by 1.4% and decrease of cooling capacity by 0.8% were observed for each 1℃ increase of outdoor air temperature. As a result, the energy efficiency ratio drops by 2% for each 1℃ increase of outdoor air temperature.

scholarly journals Energy Efficiency Study, Comparing, Commercial Grade Propane/Butane Blend; Refrigerant Grade Propane and Chlorodifluoromethane (CHClF2), Investigated in a Psychrometric Chamber

2018 ◽  
Vol 1 (2) ◽  
Author(s):  
Z. Zakaria ◽  
D. Veerasamy ◽  
J. H. Koh
Keyword(s):  
Energy Efficiency ◽  
Cooling Capacity ◽  
Air Conditioner ◽  
Liquefied Petroleum Gas ◽  
Air Conditioners ◽  
Commercial Grade ◽  
Propane Butane

The current use of hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs) as refrigerants will be phaseout and phasedown. Hydrocarbon (HC) refrigerants were introduced as potential replacements. These refrigerant grade hydrocarbons namely propane (R 290) and isobutane (R 600a) were on sale at premium prices. As Malaysia has capabilities to produce LPG, a study was conducted to find out the suitability of commercial liquefied petroleum gas (LPG) to be used as refrigerant. This study compares the efficiencies and cooling capacities of commercial grade LPG to refrigerant grade propane (C3H8) and chlorodifluoromethane (CHClF2) (R 22) in a split unit air conditioner installed in a psychrometric chamber. Results of experiments indicated that the commercial blends in the ratio of 80% propane and 20% butane provided the highest efficiency, but had the lowest cooling capacities; in contrast, the imported refrigerant grade propane despite value being purer, was not reflected in term of its efficiency; recorded the lowest. CHClF2 provided the highest efficiency and cooling capacity. LPG has the potential to replace R22 in split air conditioners despite losing 10 % in cooling capacities but instead gained 2.6% in energy efficiencies. 

A Double-Layers Energy Efficiency Evaluation Method of Central Air-Conditioning System

2013 ◽  
Vol 860-863 ◽  
pp. 1666-1669
Author(s):  
Bing Wen Wang ◽  
Yuan Yuan Liu ◽  
Shan Shan Shi ◽  
Gan Zhou ◽  
Shuang Hu Wang
Keyword(s):  
Energy Efficiency ◽  
Air Conditioning ◽  
Evaluation Method ◽  
High Energy ◽  
National Standard ◽  
Double Layers ◽  
Efficiency Evaluation ◽  
Air Conditioning System ◽  
Central Air Conditioning ◽  
Energy Efficiency Evaluation

It is necessary to monitor and optimize work status of central air-conditioning system (CACS) due to its high energy consumption. According to national standard, this paper designed a practical energy-efficiency evaluation method with double-layers structure. The upper-layer indicator reflects the whole energy efficiency of CACS. The lower-layer indicators reflect the energy efficiency of each subsystem of CACS, such as refrigeration system, chilled water system and terminal system. Using this double-layers evaluation system, the managers of CACS can not only observe the whole energy efficiency level but also find out the weak point of the system.

scholarly journals Developing a Cold Accumulator with a Capsule Bed Containing Water as a Phase-Change Material

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2703
Author(s):  
Robert Sekret ◽  
Przemysław Starzec
Keyword(s):  
Energy Efficiency ◽  
Heat Pump ◽  
Cold Storage ◽  
Cooling Capacity ◽  
Cooling Power ◽  
Storage Process ◽  
Water Ice ◽  
Measurement Results ◽  
Mathematical Relationships ◽  
Change Material

The paper presents the investigation of a prototype cold accumulator using water–ice latent heat for the cold storage process. The concept of the cold accumulator was based on a 200-L-capacity cylindrical storage tank in which spherical capsules filled with water were placed. Beds of polypropylene capsules with diameters of 80 mm, 70 mm, and 60 mm were used in the tests. The cold accumulator operated with a water–air heat pump. Based on the test results, the following parameters were calculated: the cooling capacity, cooling power, energy efficiency of the cold storage, and energy efficiency ratio (EER) of the accumulator. The obtained measurement results were described with mathematical relationships (allowing for measurement error) using criterial numbers and the developed “Research Stand Factor Number” (RSFN) index. It has been found that, for the prototype cold accumulator under investigation, the maximum values of the cooling capacity (17 kWh or 85.3 kWh per cubic meter of the accumulator), energy efficiency (0.99), and EER (4.8) occur for an RSFN of 144·10−4. The optimal conditions for the operation of the prototype cold accumulator were the closest to laboratory tests conducted for a bed with capsules with a diameter of 70 mm and a mass flow of the water–glycol mixture flowing between the accumulator and the heat pump of 0.084 kg/s. During the tests, no significant problems with the operation of the prototype cold accumulator were found.

scholarly journals Energy efficiency evaluation of oil producing economies in Africa: DEA, malmquist and multiple regression approaches

2021 ◽  
Vol 2 ◽  
pp. 100025
Author(s):  
Mark Awe Tachega ◽  
Xilong Yao ◽  
Yang Liu ◽  
Dulal Ahmed ◽  
Hui Li ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Multiple Regression ◽  
Efficiency Evaluation ◽  
Energy Efficiency Evaluation

ENERGY EFFICIENCY EVALUATION FOR A “GREEN” POWER GENERATION PROCESS WITH MINIMUM EFFORT ON CARBON DIOXIDE CAPTURE AND STORAGE

2012 ◽  
Vol 199 (12) ◽  
pp. 1642-1651 ◽  
Author(s):  
Suttichai Assabumrungrat ◽  
Janewit Phromprasit ◽  
Siriporn Boonkrue ◽  
Worapon Kiatkittipong ◽  
Wisitsree Wiyaratn ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Power Generation ◽  
Energy Efficiency ◽  
Carbon Dioxide Capture ◽  
Efficiency Evaluation ◽  
Generation Process ◽  
Green Power ◽  
Energy Efficiency Evaluation ◽  
And Storage

Design of Hybrid Mobile Service Robot

2012 ◽  
Vol 245 ◽  
pp. 255-260 ◽  
Author(s):  
Rudolf Jánoš ◽  
Mikuláš Hajduk ◽  
Ján Semjon ◽  
Ľuboslava Šidlovská
Keyword(s):  
Energy Efficiency ◽  
High Mobility ◽  
Outdoor Environment ◽  
Service Robot ◽  
Mobile Service ◽  
Mobile Platforms ◽  
Hybrid Platform ◽  
Moving Platform ◽  
Mobile Service Robot ◽  
Indoor And Outdoor

Wheels and legs are two widely accepted methodology used to move the moving platform to the ground. Wheels are human inventions, the rolls in a straight country excel in energy efficiency and speed of movement. Hybrid platform for integrating the benefits of legs and wheels with high mobility of both seems to be the "future" of mobile platforms for indoor and outdoor environment. This paper describes the design leg-wheel chassis for service robot.

Sign in / Sign up

Export Citation Format

Share Document