EFFECT OF CONTROL OPTIMIZATION OF CO2 TRANSCRITICAL SPLIT AIR CONDITIONER ON THERMAL COMFORT OF OCCUPANTS IN SINGLE ZONE ROOM

2014 ◽  
Vol 22 (01) ◽  
pp. 1450006 ◽  
Author(s):  
ASHISH KADAM ◽  
ATUL PADALKAR ◽  
S. MARTÍNEZ-BALLESTER
Keyword(s):  
Thermal Comfort ◽  
Thermal Environment ◽  
Energy Performance ◽  
Weather Data ◽  
Air Conditioner ◽  
Air Conditioners ◽  
Control Optimization ◽  
System A ◽  
Energy Environment ◽  
Thermal Comfort Model

Energy, environment and economics are considered as very vital parameters for the evaluation of an air conditioning system and associated indoor environment. The cooling performance of an air conditioner has an effect on the thermal comfort of occupants in the room. Transcritical CO 2 air conditioner (System B) with a control for gas cooler pressure has better energy performance than a transcritical CO 2 air conditioner (System A) without any control on the gas cooler pressure. An experimental technique is used for generating performance equations to define transcritical CO 2 air conditioners in the EnergyPlus program. EnergyPlus simulates combined model of a transcritical CO 2 air conditioner and room for known yearly weather data for an effect on thermal comfort in the room. Thermal comfort in the room is evaluated using the Fanger thermal comfort model and the Pierce two node model. The better energy performance of System B results in improved indoor room environment of the room. The total cooling of System B is 15.78–20.2% higher than that of System A. The Fanger thermal comfort model shows that 95% to 133% people are more dissatisfied with an indoor thermal environment during the morning and 85% to 127% people during the afternoon for a room coupled with System A vis-à-vis room with System B.

scholarly journals Optimal Air Conditioner Placement Using a Simple Thermal Environment Analysis Method for Continuous Large Spaces with Predominant Advection

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4663
Author(s):  
Tatsuhiro Yamamoto ◽  
Akihito Ozaki ◽  
Myonghyang Lee
Keyword(s):  
Air Conditioning ◽  
Thermal Environment ◽  
Fluid Dynamic ◽  
Optimal Placement ◽  
Air Conditioner ◽  
Analysis Method ◽  
Computational Fluid Dynamic Analysis ◽  
Environment Analysis ◽  
Air Conditioners ◽  
Energy Simulations

The number of houses with large, continuous spaces has increased recently. With improvements in insulation performance, it has become possible to efficiently air condition such spaces using a single air conditioner. However, the air conditioning efficiency depends on the placement of the air conditioner. The only way to determine the optimal placement of such air conditioners is to conduct an experiment or use computational fluid dynamic analysis. However, because the analysis is performed over a limited period, it is difficult to consider non-stationarity effects without using an energy simulation. Therefore, in this study, energy simulations and computational fluid dynamics analyses were coupled to develop a thermal environment analysis method that considers non-stationarity effects, and various air conditioner arrangements were investigated to demonstrate the applicability of the proposed method. The accuracy verification results generally followed the experimental results. A case study was conducted using the calculated boundary conditions, and the results showed that the placement of two air conditioners in the target experimental house could provide sufficient air conditioning during both winter and summer. Our results suggest that this method can be used to conduct preliminary studies if the necessary data are available during design or if an experimental house is used.

scholarly journals Personal Atmosphere: Estimation of Air Conditioner Parameters for Personalizing Thermal Comfort

2020 ◽  
Vol 10 (22) ◽  
pp. 8067
Author(s):  
Tomohiro Mashita ◽  
Tetsuya Kanayama ◽  
Photchara Ratsamee
Keyword(s):  
Machine Learning ◽  
Thermal Comfort ◽  
Air Temperature ◽  
Fine Tuning ◽  
Air Conditioner ◽  
Data Set ◽  
Air Conditioning System ◽  
Air Conditioners ◽  
Uniform Distributions ◽  
Machine Learning Model

Air conditioners enable a comfortable environment for people in a variety of scenarios. However, in the case of a room with multiple people, the specific comfort for a particular person is highly dependent on their clothes, metabolism, preference, and so on, and the ideal conditions for each person in a room can conflict with each other. An ideal way to resolve these kinds of conflicts is an intelligent air conditioning system that can independently control air temperature and flow at different areas in a room and then produce thermal comfort for multiple users, which we define as the personal preference of air flow and temperature. In this paper, we propose Personal Atmosphere, a machine learning based method to obtain parameters of air conditioners which generate non-uniform distributions of air temperature and flow in a room. In this method, two dimensional air-temperature and -flow distributions in a room are used as input to a machine learning model. These inputs can be considered a summary of each user’s preference. Then the model outputs a parameter set for air conditioners in a given room. We utilized ResNet-50 as the model and generated a data set of air temperature and flow distributions using computational fluid dynamics (CFD) software. We then conducted evaluations with two rooms that have two and four air conditioners under the ceiling. We then confirmed that the estimated parameters of the air conditioners can generate air temperature and flow distributions close to those required in simulation. We also evaluated the performance of a ResNet-50 with fine tuning. This result shows that its learning time is significantly decreased, but performance is also decreased.

scholarly journals Study on energy loss and thermal environment through door open while air conditioner running

2019 ◽  
Vol 111 ◽  
pp. 06035
Author(s):  
Sihwan Lee
Keyword(s):  
Energy Consumption ◽  
Indoor Air ◽  
Room Temperature ◽  
Thermal Environment ◽  
Infiltration Rate ◽  
Operating Efficiency ◽  
Air Conditioner ◽  
Air Conditioners ◽  
Cooling Period ◽  
Closed State

While air conditioner is running, opening doors and windows is a great way to reduce operating efficiency and undermine the air conditioning system’s ability to bring the indoor to a comfortable temperature. The purpose of this study is to evaluate the heat loss and thermal environment through the door open while air conditioner running. To achieve this goal, using full-scale measurement with the commercial store during the cooling period, the infiltration rate, thermal environment and energy consumption of air conditioners with door opened and door closed state were measured. The measured results show that the infiltration rate at the door opened state was increased by about 21.3 times compared to the door closed state. When the set temperature of the air conditioner was 24 °C, the room temperature in the opening gate cooling was measured to be about 5 °C higher than the closing gate cooling. However, the energy consumption was measured approximately 12 kWh/day and there was no difference with door state. This means that the energy consumption is not increased if the indoor air temperature would not reach the set point temperature of air conditioner.

A Review of the Impact of Vegetation in Solar Control towards Enhanced Thermal Comfort and Energy Performance in Buildings

2019 ◽  
Vol 887 ◽  
pp. 428-434
Author(s):  
Dorcas A. Ayeni ◽  
Olaniyi O. Aluko ◽  
Morisade O. Adegbie
Keyword(s):  
Thermal Comfort ◽  
Adaptive Capacity ◽  
Thermal Environment ◽  
Thermal Conditions ◽  
Building Design ◽  
Energy Performance ◽  
Tropical Region ◽  
Indoor Climate ◽  
Solar Control ◽  
The Impact

Man requires a thermal environment that is within the range of his adaptive capacity and if this fluctuates outside the normal, a reaction is required beyond its adaptive capacity which results to health challenges. Therefore, the aim of building design in the tropical region is to minimize the heat gain indoors and enhance evaporative cooling of the occupants of the space so as to achieve thermal comfort. In most cases, the passive technologies are not adequate in moderating indoor climate for human comfort thereby relying on active energy technique to provide the needed comfort for the building users. The need for the use of vegetation as a panacea for achieving comfortable indoor thermal conditions in housing is recognised by architects globally. However, the practice by architects in Nigeria is still at the lower ebb. The thrust of this paper therefore is to examine the impact of vegetation in solar control reducing thermal discomfort in housing thereby enhancing the energy performance of the buildings. Using secondary data, the paper identifies the benefits of vegetation in and around buildings to include improvement of indoor air quality through the aesthetics quality of the environment and concludes that vegetation in and around building will in no small measure contributes to saving energy consumption.

scholarly journals The effects of building layouts and envelope on indoor thermal environment of Hui style traditional buildings in Wuyuan

2020 ◽  
Vol 194 ◽  
pp. 05013
Author(s):  
Xiaowei Hong ◽  
Guangjin Zhang ◽  
Yufeng Zhang
Keyword(s):  
Quantitative Analysis ◽  
Thermal Comfort ◽  
Air Temperature ◽  
Indoor Air ◽  
Thermal Environment ◽  
Field Investigation ◽  
Indoor Thermal Environment ◽  
Adaptive Thermal Comfort ◽  
Thermal Comfort Model

Indoor thermal environment of Hui style traditional houses is depended on surrounding environments, building layouts and envelope. Quantitative analysis of the effects of building layouts and envelope on indoor thermal environment is of great significance for preventions of traditional houses and design of new archaized houses. A field investigation was conducted on thirty-six traditional houses from nine villages in Wuyuan, and the typical buildings’ layout and envelope were determined. Four traditional buildings in different location in Wuyuan were selected for continual recording. The four buildings with four types of building layouts and envelope were analyzed by using local adaptive thermal comfort model, and the effects of building layouts and envelope of traditional buildings were clearly revealed. The most crucial way to improve indoor thermal environment in Hui style traditional buildings was raising the indoor air temperature.

scholarly journals Thermal and Vibration Comfort Analysis of a Nearly Zero-Energy Building in Poland

2018 ◽  
Vol 10 (10) ◽  
pp. 3774 ◽  
Author(s):  
Małgorzata Fedorczak-Cisak ◽  
Marcin Furtak ◽  
Jolanta Gintowt ◽  
Alicja Kowalska-Koczwara ◽  
Filip Pachla ◽  
...  
Keyword(s):  
Thermal Comfort ◽  
Thermal Environment ◽  
Building Design ◽  
Energy Performance ◽  
Zero Energy ◽  
Technical Requirements ◽  
Low Energy Buildings ◽  
Passive Houses ◽  
Construction Law ◽  
The Impact

Placing emphasis exclusively on minimizing energy consumption in low-energy buildings can adversely impact thermal comfort and vibrational comfort. Vibrational comfort is extremely important in building design, especially within mining or seismically active territories, and due to car transportation in city centers. In this article, a new approach to designing passive buildings and nearly zero-energy buildings (NZEBs) in Poland is proposed, which has a strong emphasis on the necessity of providing comfort of use in passive houses and NZEBs. Additionally, vibration comfort provisions in the design process are examined. The research gap that will be addressed by the research presented in this article is to extend the comfort conditions of passive buildings and NZEBs into the area of vibratory comfort. The second goal of the project is to determine the impact of solar control systems on the conditions of thermal comfort. The conclusions from the research will allow for the optimization of design assumptions for passive houses and NZEBs. The conclusions from the tests can serve as the basis for introducing appropriate construction law requirements in Poland. The results of the research, which are presented in the article, indicate that the technical requirements that are applicable in Poland ought to include requirements regarding the use of sun blinds in NZEBs and passive buildings (not only as recommendations). In particular, the use of apertures on the south side ought to be mandated. The article can also be the basis for introducing the requirements of vibration comfort to the PN–EN 15251:2012 “Indoor environmental input parameters for design and assessment of energy performance of buildings addressing indoor air quality, thermal environment, lighting and acoustics” standard, which is the basis for designing the parameters of the internal environment for buildings.

Study on Outdoor and Semi-Outdoor Thermal Comfort of College Campus in Central Taiwan

2014 ◽  
Vol 1030-1032 ◽  
pp. 624-628
Author(s):  
Wen Pei Sung ◽  
Shih Tai Hu ◽  
Yu Kuang Zhao ◽  
Lei Wei
Keyword(s):  
Thermal Comfort ◽  
Thermal Environment ◽  
Outdoor Environment ◽  
Outdoor Thermal Comfort ◽  
Small Island ◽  
Air Conditioner ◽  
Subtropical Zone ◽  
Outdoor Thermal Environment ◽  
Outdoor Comfort ◽  
Central Taiwan

Taiwan is a small island. Some of college campuses are very tiny with large hard pavement to cause un-comfortable outdoor environment. Most of faculty and students like to stay at classroom and use air-conditioner to establish comfort thermal environment. Thus, the outdoor and semi-outdoor thermal equipments are used to detect the parameters of weather. The test and analysis results show that hard pavements cause the un-comfortable outdoor comfort. Mean Radiant Temperatures of grass in summer is higher than the other pavement because that grass pavement is lack of moisture to causes bad outdoor thermal comfort. Therefore, the fine outdoor and semi-outdoor thermal comfort environment should consider the permeable pavement and grass with suitable moisture to cause better outdoor thermal environment and large arbores should be planted widely in campus to establish a better semi-outdoor thermal temperature in campus of the subtropical zone.

scholarly journals Coupling a Building Energy Simulation Tool with a Microclimate Model to Assess the Impact of cool Pavements on the Building’s Energy Performance. Application in a Dense Residential Area

2019 ◽  
Vol 11 (9) ◽  
pp. 2519 ◽  
Author(s):  
Tsoka ◽  
Tsikaloudaki ◽  
Theodosiou
Keyword(s):  
Urban Areas ◽  
Energy Demand ◽  
Thermal Environment ◽  
Energy Performance ◽  
Computational Method ◽  
Weather Data ◽  
Building Unit ◽  
Heating And Cooling ◽  
Data Generator ◽  
The Impact

Replacing conventional pavements with the corresponding high albedo ones constitutes a well-known technique to improve outdoor thermal environment of modern cites. Since most of the existing studies assess the impact of the high albedo pavements at the pedestrian’s height and with respect to thermal comfort, this study aims to examine the effect of the application of highly reflective pavements on the heating and cooling energy needs of a building unit, located inside a dense urban area. Aiming at a higher accuracy of the energy performance simulations, an integrated computational method between ENVI-met model, Meteonorm weather data generator and Energy Plus software is established, to consider the site-specific microclimatic characteristics of the urban areas. The analysis is performed both for the design and the aged albedo values as significant changes may occur due to aging process. The analysis revealed that the application of cool materials on the ground surfaces only marginally affects the energy performance of the examined building unit, both for the design and the aged albedo value; changes on the annual heating and cooling energy demand, for both albedo scenarios did not exceed 1.5% revealing the limited potential of cool pavements regarding the improvement of the energy performance of urban building units.

scholarly journals Research on Indoor Thermal Comfort and Age of Air in Qilou Street Shop under Mechanical Ventilation Scheme: A Case Study of Nanning Traditional Block in Southern China

2021 ◽  
Vol 13 (7) ◽  
pp. 4037
Author(s):  
Xianfeng Huang ◽  
Chen Qu
Keyword(s):  
Mechanical Ventilation ◽  
Air Quality ◽  
Thermal Comfort ◽  
Thermal Environment ◽  
Southern China ◽  
Air Conditioner ◽  
Indoor Thermal Environment ◽  
Indoor Thermal Comfort ◽  
Circulation Mode ◽  
Ventilation Scheme

In hot summers, air conditioning (AC) and mechanical ventilation (such as fans) are used as cooling modes that strongly influence the resultant indoor environment, like thermal comfort and air quality in the shops of a Nanning arcade street (qilou). The air circulation mode in shops greatly affects the indoor thermal environment and level of air freshness. The approaches for effectively improving the indoor thermal comfort and air quality are developed in qilou street shops with air-conditioner in a humid and hot region in southern China. Consequently, the purpose of this study is to assess different ventilation schemes in order to identify the best one. By using two indices, i.e., the predicted mean vote (PMV) and the age of air (AoA), in situ measurement and numerical simulation are conducted to investigate humans’ thermal comfort in extreme summer. Then, the indoor thermal comfort and AoA levels in summer under three different ventilation schemes (upper-inlet–upper-outlet, upper-inlet–bottom-outlet, and side-inlet–side-outlet) are comparatively analyzed through numerical computations of the indoor thermal environment. The results show that the upper-inlet–upper-outlet mode of the AC ventilation scheme led to the creation of a favorable air quality and comfortable thermal environment inside the shop, which will help designers understand the influence of the ventilation scheme on the indoor thermal comfort and health environment.

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