scholarly journals Comparative Analysis of Energy Use and Human Comfort by an Intelligent Control Model at the Change of Season

Energies ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 6023
Author(s):  
Sung Hoon Yoon ◽  
Jonghoon Ahn
Keyword(s):  
Thermal Comfort ◽  
Intelligent Control ◽  
Energy Use ◽  
Thermal Environment ◽  
Operating Time ◽  
Adaptive Controller ◽  
Indoor Thermal Comfort ◽  
Heating And Cooling ◽  
Proposed Model ◽  
Deterministic Control

For improving control methods in the thermal environment, various algorithms have been studied to satisfy the specific conditions required by the characteristics of building spaces and to reduce the energy consumed in operation. In this research, a network-based learning control equipped with an adaptive controller is proposed to investigate the control performance for supply air conditions with maintaining the levels of indoor thermal comfort. In order to examine its performance, the proposed model is compared to two different models in terms of the patterns of heating and cooling energy use and the characteristics of operational signals and overshoots. As a result, the energy efficiency of the proposed control has been slightly decreased due to the energy consumption increased by precise controls, but the thermal comfort has improved by about 10.7% more than a conventional thermostat and by about 19.8% more than a deterministic control, respectively. This result can contribute to the reduction of actual installation and maintenance costs by reducing the operating time of dampers and the energy use of heating coils without compromising indoor thermal comfort.

scholarly journals Importance of Behavioral Adjustments for Adaptive Thermal Comfort in a Condominium with HEMS System

2020 ◽  
Vol 15 (3) ◽  
pp. 163-170
Author(s):  
Rajan KC ◽  
Hom Bahadur Rijal ◽  
Masanori Shukuya ◽  
Kazui Yoshida
Keyword(s):  
Thermal Comfort ◽  
Air Temperature ◽  
Energy Use ◽  
Thermal Environment ◽  
Residential Buildings ◽  
Outdoor Environment ◽  
Adaptive Behaviors ◽  
Outdoor Air ◽  
Indoor Thermal Environment ◽  
Indoor Thermal Comfort

The energy use in residential dwellings has been increasing due to increasing use of modern electric appliances to make the lifestyle easier, entertaining and better. One of the major purposes of indoor energy use is for improving indoor thermal environment for adjusting thermal comfort. Along with the use of passive means like the use of mechanical devices, the occupants in any dwellings use active means such as the use of natural ventilation, window opening, and clothing adjustment. In fact, the use of active means when the outdoor environment is good enough might be more suitable to improve indoor thermal environment than the use of mechanical air conditioning units, which necessarily require electricity. Therefore, the people in developing countries like Nepal need to understand to what extent the occupants can use active means to manage their own indoor thermal comfort. The use of active means during good outdoor environment might be an effective way to manage increasing energy demand in the future. We have made a field survey on the occupants’ adaptive behaviors for thermal comfort in a Japanese condominium equipped with Home Energy Management System (HEMS). Online questionnaire survey was conducted in a condominium with 356 families from November 2015 to October 2016 to understand the occupants’ behaviors. The number of 17036 votes from 39 families was collected. The indoor air temperature, relative humidity and illuminance were measured at the interval of 2-10 minutes to know indoor thermal environmental conditions. The occupants were found using different active behaviors for thermal comfort adjustments even in rather harsh summer and winter. Around 80% of the occupants surveyed opened windows when the outdoor air temperature was 30⁰C in free running (FR) mode and the clothing insulation was 0.93 clo when the outdoor air temperature was 0⁰C. The result showed that the use of mechanical heating and cooling was not necessarily the first priority to improve indoor thermal environment. Our result along with other results in residential buildings showed that the adaptive behaviors of the occupants are one of the primary ways to adjust indoor thermal comfort. This fact is important in enhancing the energy saving building design.

scholarly journals Behavioural Adaptation for the Thermal Comfort and Energy Saving in Japanese Offices

2019 ◽  
Vol 15 (2) ◽  
pp. 14-25
Author(s):  
Hom B. Rijal ◽  
Michael A. Humphreys ◽  
J. Fergus Nicol
Keyword(s):  
Thermal Comfort ◽  
Energy Use ◽  
Thermal Environment ◽  
Office Buildings ◽  
Behavioural Adaptation ◽  
Indoor Thermal Environment ◽  
Heating And Cooling ◽  
Adaptive Thermal Comfort ◽  
Window Opening ◽  
Behavioural Adaptations

Office workers use a variety of adaptive opportunities to regulate their indoor thermal environment. The behavioural adaptations such as window opening, clothing adjustments, and use of heating/cooling are important factors for adaptive thermal comfort. It is well-known that they are the most important contributors in the adaptive thermal comfort model. Thus, if we understand the behavioural adaptation properly, we can explain the mechanism of the adaptive model. The indoor thermal environment is often adjusted using the air conditioning in Japanese office buildings to improve thermal comfort and productivity. Thus, it is necessary to conduct research on the behavioural adaptation in the offices because the occupant behavior is different from behaviour in dwellings. In order to record the seasonal differences in behavioural adaptation and to develop an adaptive algorithm for Japanese offices, we measured temperatures in 11 office buildings and conducted the thermal comfort and occupant behaviour survey for over a year. We collected 4,660 samples from about 1,350 people. The proportion of ‘open window’ in the free running mode (neither heating nor cooling being used) is significantly higher than that of the air conditioned mode. The behavioural adaptation is related to the outdoor air temperature. The behavioural adaptations such as window-opening, heating and cooling use predicted by regression analysis are in good agreement with the measured data. These findings can be applied to building thermal simulation to predict the behavioural adaptation and energy use in office buildings.

scholarly journals Improvement of the Performance Balance between Thermal Comfort and Energy Use for a Building Space in the Mid-Spring Season

2020 ◽  
Vol 12 (22) ◽  
pp. 9667
Author(s):  
Jonghoon Ahn
Keyword(s):  
Energy Consumption ◽  
Thermal Comfort ◽  
Energy Use ◽  
Learning Algorithm ◽  
Adaptive Controller ◽  
Comfort Level ◽  
Adaptive Model ◽  
Comfort Levels ◽  
Proposed Model ◽  
High Consistency

In thermal controls in buildings, recent statistical and data-driven approaches to optimize supply air conditions have been examined in association with several types of building spaces and patterns of energy consumption. However, many strategies may have some problems where high-control precision may increase energy use, or low energy use in systems may decrease indoor thermal quality. This study investigates a neural network algorithm with an adaptive model on how to control the supply air conditions reflecting learned data. During the process, the adaptive model complements the signals from the network to independently maintain the comfort level within setting ranges. Although the proposed model effectively optimizes energy consumption and supply air conditions, it achieves quite improved comfort levels about 14% more efficient than comparison models. Consequently, it is confirmed that a network and learning algorithm equipped with an adaptive controller properly responds to users’ comfort levels and system’s energy consumption in a single space. The improved performance in space levels can be significant in places where many spaces are systematically connected, and in places which require a high consistency of indoor thermal comfort. Another advantage of the proposed model is that it properly reduces an increase in energy consumption despite an intensive strategy is utilized to improve thermal comfort.

scholarly journals Impacts on Indoor Thermal Comfort and Heating Energy Use in Hellenic Dwellings from Occupant Behavioral Reactions

2021 ◽  
Vol 11 (14) ◽  
pp. 6254
Author(s):  
Elena G. Dascalaki ◽  
Constantinos A. Balaras
Keyword(s):  
Thermal Comfort ◽  
Energy Use ◽  
Energy Savings ◽  
Local Heating ◽  
Economic Recession ◽  
Heating System ◽  
Building Stock ◽  
Heating Systems ◽  
Indoor Thermal Comfort ◽  
Energy Audits

In an effort to reduce the operational cost of their dwellings, occupants may even have to sacrifice their indoor thermal comfort conditions. Following the economic recession in Greece over recent years, homeowners have been forced to adapt their practices by shortening heating hours, lowering the indoor thermostat settings, isolating spaces that are not heated or even turning off their central heating system and using alternative local heating systems. This paper presents the results from over 100 occupant surveys using questionnaires and walk-through energy audits in Hellenic households that documented how occupants operated the heating systems in their dwellings and the resulting indoor thermal comfort conditions and actual energy use. The results indicate that the perceived winter thermal comfort conditions were satisfactory in only half of the dwellings, since the actual operating space heating periods averaged only 5 h (compared with the assumed 18 h in standard conditions), while less than half heated their entire dwellings and only a fifth maintained an indoor setpoint temperature of 20 °C, corresponding to standard comfort conditions. Mainstream energy conservation measures include system maintenance, switching to more efficient systems, reducing heat losses and installing controls. This information is then used to derive empirical adaptation factors for bridging the gap between the calculated and actual energy use, making more realistic estimates of the expected energy savings following building renovations, setting prudent targets for energy efficiency and developing effective plans toward a decarbonized building stock.

scholarly journals Energy-saving potential of intermittent heating system: Influence of composite phase change wall and optimization strategy

2020 ◽  
pp. 014459872096921
Author(s):  
Yanru Li ◽  
Enshen Long ◽  
Lili Zhang ◽  
Xiangyu Dong ◽  
Suo Wang
Keyword(s):  
Energy Consumption ◽  
Thermal Comfort ◽  
Phase Change ◽  
Air Temperature ◽  
Indoor Air ◽  
Thermal Environment ◽  
Optimization Strategy ◽  
Indoor Thermal Environment ◽  
Indoor Thermal Comfort ◽  
Intermittent Heating

In the Yangtze River zone of China, the heating operation in buildings is mainly part-time and part-space, which could affect the indoor thermal comfort while making the thermal process of building envelope different. This paper proposed to integrate phase change material (PCM) to building walls to increase the indoor thermal comfort and attenuate the temperature fluctuations during intermittent heating. The aim of this study is to investigate the influence of this kind of composite phase change wall (composite-PCW) on the indoor thermal environment and energy consumption of intermittent heating, and further develop an optimization strategy of intermittent heating operation by using EnergyPlus simulation. Results show that the indoor air temperature of the building with the composite-PCW was 2–3°C higher than the building with the reference wall (normal foamed concrete wall) during the heating-off process. Moreover, the indoor air temperature was higher than 18°C and the mean radiation temperature was above 20°C in the first 1 h after stopping heating. Under the optimized operation condition of turning off the heating device 1 h in advance, the heat release process of the composite-PCW to the indoor environment could maintain the indoor thermal environment within the comfortable range effectively. The composite-PCW could decrease 4.74% of the yearly heating energy consumption compared with the reference wall. The optimization described can provide useful information and guidance for the energy saving of intermittently heated buildings.

scholarly journals Optimization of Window Design for Daylight and Thermal Comfort in Cold Climate Conditions

Energies ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 8013
Author(s):  
Tony-Andreas Arntsen ◽  
Bozena Dorota Hrynyszyn
Keyword(s):  
Thermal Comfort ◽  
Energy Demand ◽  
National Level ◽  
Cold Climate ◽  
Alternative Methods ◽  
Indoor Thermal Comfort ◽  
Heating And Cooling ◽  
Overall Performance ◽  
European Standards ◽  
Window Design

Window design affects the overall performance of a building. It is important to include window design during the initial stages of a project since it influences the performance of daylight and thermal comfort as well as the energy demand for heating and cooling. The Norwegian building code facilitates two alternative methods for achieving a sufficient daylight, and only guidelines for adequate indoor thermal comfort. In this study, a typical Norwegian residential building was modeled to investigate whether the criteria and methods facilitate consistent and good performance through different scenario changes and furthermore, how the national regulations compare to European standards. A better insulated and more air-tight building has usually a lower annual heating demand, with only a marginal decrease in the daylight performance when the window design is unchanged. A more air-tight construction increases the risk of overheating, even in cold climates. This study confirms that a revision of the window design improves the overall performance of a building, which highlights the importance of proper window design. The pursuit of lower energy demand should not be at the expense of indoor thermal comfort considering the anticipated future weather conditions. This study indicates that criteria for thermal comfort and daylight, if clearly defined, can affect the energy demand for heating and cooling, as well as the indoor climate positively, and should be taken into account at the national level. A comparison between the national regulations and the European standards was made, and this study found that the results are not consistent.

scholarly journals Performance Analyses of Temperature Controls by a Network-Based Learning Controller for an Indoor Space in a Cold Area

2020 ◽  
Vol 12 (20) ◽  
pp. 8515 ◽  
Author(s):  
Jonghoon Ahn
Keyword(s):  
Energy Consumption ◽  
Thermal Comfort ◽  
Energy Use ◽  
Fuzzy Logic Controller ◽  
Sustainable Use ◽  
Adaptive Controller ◽  
Comfort Level ◽  
Effective Control ◽  
Control Precision ◽  
Neural Network Controller

For the sustainable use of building spaces, various methods have been studied to satisfy specific conditions required by the characteristics of space types and the energy use in operation. However, several effective control approaches adopting the latest statistical tools may have problems such as higher control precision increases energy consumption, or lower energy consumption decreases their control precision. This study proposes an optimized model to reach the indoor set-point temperature by controlling the amount of heating supply air and its temperature and investigates the efficiency of an adaptive controller to maintain indoor thermal comfort within setting ranges. In the consistency of the comfort level, the fuzzy logic controller was found to be 1.76% and the artificial neural network controller to be 17.83%, respectively, more efficient than the conventional thermostat. In addition, for energy use efficiency, both of the controllers were confirmed to be over 3.0% more efficient. Consequently, the network-based controller with the adaptive controller checking comfort levels effectively works to improve both energy efficiency and thermal comfort. This improvement can be significant in places such as commercial high-rises, large hospitals, and data centers where many spaces are intensively woven with appropriate thermal environments to maintain users’ workability.

Quantitative investigations on setting parameters of air conditioning (air-supply speed and temperature) in ventilated cooling rooms

2019 ◽  
Vol 30 (1) ◽  
pp. 99-113 ◽  
Author(s):  
Haofu Chen ◽  
Zhuangbo Feng ◽  
Shi-Jie Cao
Keyword(s):  
Thermal Comfort ◽  
Air Conditioning ◽  
Thermal Environment ◽  
Inertial Force ◽  
Index Formula ◽  
Design Parameters ◽  
Dimensionless Number ◽  
Indoor Thermal Environment ◽  
Indoor Thermal Comfort ◽  
Air Supply

Rational and scientific design of indoor air conditioning is essential. In the design of Heating, Ventilating and Air Conditioning system, air-supply speed (ventilation rate) and air-supply temperature are the two most important parameters. In the current study, numerical simulations and experimental measurements were adopted to investigate the influences of ventilation mode, air-supply velocity and air-supply temperature on indoor thermal comfort as well as building energy consumption in summer. Different ventilation modes (up supply and down exit, ceiling supply and ceiling exit) were considered in modelling. Based on the simulation and experimental results, dimensionless index [Formula: see text] is proposed, which represents the ratio of buoyancy weighting force to inertial force. This index can be used as a pre-evaluation index of indoor thermal comfort in preliminary design of air conditioning. It is an indicator to judge the working conditions in cooling-ventilated rooms. When [Formula: see text], the settlement and diffusion effects of indoor airflow reach a good level, which means that the parameter setting could provide a comfortable indoor thermal environment. The dimensionless number [Formula: see text] is a theoretically based tool in the pre-evaluation of indoor thermal environment, providing guidance for setting of ventilation design parameters.

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