Thermal Comfort Control Research Articles

ENERGY EFFICIENCY OF A VARIABLE SPEED OF THE CENTRALIZED AIR CONDITIONING SYSTEM USING PID CONTROLLER

PID control system for air-conditioning system in residence is presented in this manuscript. The control strategy is focused on low energy consumption and thermal comfort for indoor user. The algorithm is developed to control the compressor speed at an appropriate speed according to the temperature inside the controlled area using PID controller. Software is developed to measure and interface the system with controlling the system according to the algorithm. The temperature settings are 20, 22 and 24oC with internal heat load of 0 and 1000 Watt. The results obtained proved that the technique can lower the energy consumption and increased temperature control for better thermal comfort compared to on/off controller

BLACK BOX MODELLING THE THERMAL BEHAVIOUR OF IHOUSE USING AUTO REGRESSIVE AND MOVING AVERAGE (ARMA) MODEL

Modelling and simulation of the dynamic thermal behaviour of a building is important to test any proposed thermal comfort control system and strategy in the building. A simulation model can be obtained by using either the white box, grey box or black box modelling method. This research focuses on the usage of auto regressive and moving average (ARMA) model, a type of black box model that represents the dynamic thermal behaviour of iHouse testbed and uses real recorded data from the testbed and limited knowledge regarding the physical characteristics of the testbed. The performance of the ARMA model developed in this research is compared with the performance of House Thermal Simulator, a previously developed model, based on grey box modelling. Results obtained shows that ARMA model works better than House Thermal Simulator in some aspects.

The Effect of the Gravity Loading Countermeasure Skinsuit Upon Movement and Strength.

Carvil, PA, Attias, J, Evetts, SN, Waldie, JM, and Green, DA. The effect of the gravity loading countermeasure skinsuit upon movement and strength. J Strength Cond Res 31(1): 154-161, 2017-Effective countermeasures against musculoskeletal deconditioning induced by microgravity and disuse are required. A simple alternative to provision of artificial gravity by centrifugation is compressive axial loading. The Russian "Pingvin" suit was the first wearable suit to apply this concept using bungee cords tethered around the shoulders and feet. However, poor loading characteristics and severe thermal and movement discomfort were reported. The gravity loading countermeasure skinsuit (GLCS) uses a bidirectional weave to generate staged axial loading from shoulders to feet, better mimicking how Earth's gravity induces progressive loading head to foot. The Mk III GLCS's loading was evaluated and tolerability assessed during maximal joint motion, ambulation, and selected strength exercises. Eight subjects (5 male and 3 female; 28 ± 3 years; 179 ± 0.1 cm and 74.8 ± 2.9 kg), having given written informed consent, had an Mk III GLCS individually tailored. Axial loading imparted, body height, joint range of motion (ROM), ambulation, and strength tests (12 repetition maximum) were performed in the GLCS and gym attire, with subjective (rating of perceived exertion, thermal comfort, movement discomfort and body control) ratings recorded throughout. Gravity loading countermeasure skinsuit provided significant axial loading when standing but significantly reduced knee (-13°), spinal (-28°) and shoulder flexion/extension ROM (-34°/-13°), in addition to Sit and Reach (-12.8 cm). No thermal issues were reported but there was an increase in subjective discomfort. Gravity loading countermeasure skinsuit did not significantly impede strength exercise, with the exception of shoulder press. The GLCS (Mk III) demonstrates potential as a countermeasure by providing tolerable, static axial loading. Furthermore, it may serve as an elasticlike strength exercise adjunct, which may have utility as a rehabilitation modality after further design refinement.

Deducing the classification rules for thermal comfort controls using optimal method

This study investigates the feasibility of using a rule set of human thermal sensation index to control a heating ventilation and air conditioning (HVAC) system in order to achieve a desired thermal comfort level and energy savings. A novel approach based on an optimization method is developed to deduce the rules of learning human thermal comfort. In contrast to conventional thermal comfort levels, the proposed approach explains the linguistic rules in an “If … Then” form, in which proposed thermal comfort levels do not require an iterative solution and can be easily adjusted, depending on the specific thermal sensation of occupants. Results of this study demonstrate that the proposed thermal comfort control mechanism can also be implemented to achieve thermal comfort, energy savings, and reduce computational costs.

스마트 쾌적 알고리즘을 적용한 실내 쾌적 제어에 대한 연구

Thermal comfort is one of the fundamental aspects of indoor environmental quality and it is strongly related to occupant satisfaction and energy used in building. In this paper, we proposes smart comfort algorithm that save energy and provide a pleasant and comfortable environment for workers by the indoor comfort conditions(Predictive Mean Vote) detection and controlling the temperature and humidity, air flow. Simulation results, heating and cooling control of the thermal comfort control can be compared with the existing general air conditioners reduces the power of 0.5kW and indoor comfort can be maintained. Also, It showed a 49.2% improvement in the light by lighting control algorithm.

Occupant feedback based model predictive control for thermal comfort and energy optimization: A chamber experimental evaluation

In current centralized building climate control, occupants do not have much opportunity to intervene the automated control system. This study explores the benefit of using thermal comfort feedback from occupants in the model predictive control (MPC) design based on a novel dynamic thermal sensation (DTS) model. This DTS model based MPC was evaluated in chamber experiments. A hierarchical structure for thermal control was adopted in the chamber experiments. At the high level, an MPC controller calculates the optimal supply air temperature of the chamber heating, ventilation, and air conditioning (HVAC) system, using the feedback of occupants’ votes on thermal sensation. At the low level, the actual supply air temperature is controlled by the chiller/heater using a PI control to achieve the optimal set point. This DTS-based MPC was also compared to an MPC designed based on the Predicted Mean Vote (PMV) model for thermal sensation. The experiment results demonstrated that the DTS-based MPC using occupant feedback allows significant energy saving while maintaining occupant thermal comfort compared to the PMV-based MPC.

Thermal Response of Different Body Parts: The Fingertip as Control Sensor for Personalized Heating

The need for individual comfort led to the development of personalized HVAC systems. These systems have positive impact on human thermal comfort and allow to achieve energy reductions due to more effective localized energy use. However, the process control of these personalized conditionings systems is still rather traditional and not really optimal. A novel approach to process control of the personalized HVAC systems by using the human body as a sensor in the control loop. The skin temperature of specific body parts play a prominent role in thermal comfort, particularly in cool environments. A proof-of-the-concept study showed the potential of such a process control concept. In this paper the results of several experiments, focussing on the behaviour of especially the fingers are compared and discussed. This showed the fingers to be most suited to monitor and to use as an indicator for the thermal comfort control of personalized heating systems.

High Dynamic Range Imaging system for Energy Optimization in Daylight - Artificial Light Integrated Scheme

This paper explains High Dynamic Range Imaging (HDRI) technology for the control and optimization of visual comfort, thermal comfort and energy consumption in daylight-artificial light integrated scheme. The objective of this work is to incorporate image sensors, Wi-Fi and ZigBee to make an economical solution for reducing energy consumption while improving visual comfort levels. The camera based fuzzy model presented determines the position of blinds ensuring visual and thermal comfort by reducing glare and maintaining uniformity. MATLAB – SIMULINK technical computing and visualizing environment is used to obtain the complete system including making HDR images, calibration of camera, formulation of control algorithm for artificial light and window blind control as well as to analyse the quality aspects of daylight-artificial light integrated scheme.

Fuzzy logic-based advanced on–off control for thermal comfort in residential buildings

Abstract In this paper, an advanced on–off control method based on fuzzy logic is proposed for maintaining thermal comfort in residential buildings. Due to the time-lag of the control systems and the late building thermal response, an anticipative control mechanism is required to reduce energy loss and thermal discomfort. The proposed controller is implemented based on an on–off controller combined with a fuzzy algorithm. On–off control was chosen over other conventional control methods because of its structural simplicity. However, because conventional on–off control has a fixed operating range and a limited ability for improvements in control performance, fuzzy theory can be applied to overcome these limitations. Furthermore, a fuzzy-based solar energy compensation algorithm can be applied to the proposed controller to compensate for the energy gained from solar radiation according to the time of day. Simulations were conducted to compare the proposed controller with a conventional on–off controller under identical external conditions such as outdoor temperature and solar energy; these simulations were carried out by using a previously reported thermal analysis program that was modified to consider such external conditions. In addition, experiments were conducted in a residential building called Green Home Plus, in which hydronic radiant floor heating is used; in these experiments, the proposed system performed better than a system employing conventional on–off control methods.

실내 온열환경 쾌적 제어를 위한 단순 PMV 회귀모델의 적용에 관한 시뮬레이션 연구

The PMV regression analysis was conducted for this model based on a database of the PMV variables. PMV regression model simplification was completed through sensitivity and data analysis. The simplified PMV regression model`s and Fanger PMV model was confirmed through MAE and RMSE. And the EMS in EnergyPlus was used to establish a simplified PMV regression analysis-based thermal comfort control. Also, the thermal comfort controls based on simplified PMV model and the Fanger PMV model were applied to the building model, it was confirmed that both controls met the thermal comfort range in more than 90% of cases during the air conditioning period.

The CPS-Based Simulation of Indoor Thermal Comfort Control with Energy Saving

Thanks to the advances of computer science, communication technology and control technology, more and more complicated cyber-physical systems (CPSs) are created to provide services in the field of smart building, traffic transportation, industry automation et al. Modeling and simulation has become an import part of the design, test and validation processes for such complicated systems. In this paper, the authors propose a CPS-based simulation method for the indoor thermal comfort control problem. Their method is based on multi-agent technology. Different human models are analyzed based on comfort and energy cost to show the effectiveness of simulation and potential of energy saving.

Assessing thermal comfort and energy efficiency in tropical African offices using the adaptive approach

Purpose – The purpose of this paper is to adduce the most appropriate thermal comfort assessment method for determining human thermal comfort and energy efficient temperature control in office buildings in tropical West Africa. Design/methodology/approach – This paper examines the Adaptive Thermal Comfort Standard, from its research evolution to its contemporary use as an environmental design assessment Standard. It compares the adaptive component of ASHRAE Standard 55 and the European CEN/EN 15251. It begins by reviewing relevant literature and then produces a comparative analysis of the two standards, before suggesting the most appropriate Adaptive Thermal Comfort Standard for use in assessing conditions in tropical climate conditions. The suggested Standard was then used to analyse data collected from the author's pilot research into thermal conditions, in five office buildings situated in the city of Enugu, South Eastern Nigeria. Findings – The paper provides insight as to why the ASHRAE adaptive model is more suitable for thermal comfort assessment of office buildings in the tropical West African climate. This was demonstrated by using the ASHRAE Thermal Comfort Standard to assess comfort conditions from pilot research study data collected on Nigerian office buildings by the author. Originality/value – The paper compares the adaptive component of ASHRAE Standard 55 with CEN/EN 15251, and their different benefits for use in tropical climates. It suggested the need for further research studies and application of the ASHRAE Adaptive Thermal Comfort Standard in the tropical West African climate.

Parametric study on the performance of green residential buildings in China

The parametric study of the indoor environment of green buildings focuses on the quantitative and qualitative improvement of residential building construction in China and the achievement of indoor thermal comfort at a low level of energy use. This study examines the effect of the adaptive thermal comfort of indoor environment control in hot summer and cold winter (HSCW) zones. This work is based on a field study of the regional thermal assessment of two typical cases, the results of which are compared with simulated results of various scenarios of “energy efficiency” strategy and “healthy housing” environmental control. First, the simulated results show that the adaptive thermal comfort of indoor environment control is actually balanced in terms of occupancy, comfort, and energy efficiency. Second, adaptive thermal comfort control can save more energy for heating or cooling than other current healthy housing environmental controls in China׳s HSCW zone. Moreover, a large proportion of energy use is based on the subjective thermal comfort demand of occupants in any building type. Third, the building shape coefficient cannot dominate energy savings. The ratio of the superficial area of a building to the actual indoor floor area has a significant positive correlation with and affects the efficiency of building thermal performance.

Model Predictive Control of thermal comfort as a benchmark for controller performance

Abstract Assessing controller performance in normal operation needs reproducible conditions and comparison with the best possible result. Tests in emulation are reproducible. Model Predictive Control (MPC) gives the best possible performance when the future inputs and the model of the process are known. When the benchmark is used for building energy management, the cost function of MPC becomes a linear programming problem with constraints given by the comfort. In emulation, the model of the building used in MPC may be obtained by gray-box parameter identification, using signals which excite all the modes of the complete model. The proposed benchmark was used to test a PID and a scheduled start PID-based energy management system. During the test periods, the MPC benchmark always outperformed the PID controllers. It reduced the occupants' discomfort by up to 97%, the energy consumption by up to 18%, and the number of on–off cycles of heat pump by up to 78%.

A room simulation tool for thermal comfort control in a bioclimatic building: A real example of use with an optimal controller

SummaryA key objective in the European Union climate and energy package for 2020 is the reduction of energy consumption. Buildings are responsible for more that one third of global energy consumption, where heating, ventilation, and air conditioning systems account for more than half of it. In extreme climates, the existing passive measures of bioclimatic buildings are not enough at time to maintain a suitable users’ thermal comfort. However, this thermal comfort must be reached reducing the energy spent by the heating, ventilation, and air conditioning system of the building. Control systems, and more specifically model predictive control, are a suitable way to find a trade‐off between users’ thermal comfort and energy saving. Simulation tools are essential for the efficient and automated testing and validation of these control strategies. This paper presents a simulation tool of an office room from a bioclimatic building, namely, the CDdI‐CIESOL‐ARFRISOL building, to test advanced control strategies against a simulation model, to evaluate them, in terms of users comfort and energy consumption, and to validate them, considering the real room itself. Details about the simulation tool are given, together with the evaluation of its goodness through a real test using a nonlinear model predictive control in an office room of that building. Copyright © 2014 John Wiley & Sons, Ltd.

EVALUATION OF USER COMFORT IN TUNNEL FORMWORK HOUSING AREAS: Izmir as a Case Study

Houses are spaces where we spend most of our lives, meeting our accommodation needs and reflecting us and our personality. The tunnel formwork systems are effective in house production. They appeal to the people in different social status varying from high-incomers to low-incomers from the city center to the peripheries of city. Based on such determination, the satisfaction of house user set forth the main line of work. For this purpose, six parameters have been ascertained to determine the user’s comfort, by interrogating the comfort of interior space in the houses: The thermal comfort, visual comfort, acoustic comfort, humidity and moisture control and design quality. With the purpose of interrogating the user’s satisfaction, four mass housing areas constructed with tunnel formwork system in İzmir have been investigated. These are: Gaziemir Emlak Bankası Houses, TOKI Uzundere Houses, Mavişehir Stage I and Mavişehir Soyak Houses. After providing general information about all these mass houses, the surveys applied to the users have been evaluated.

The control of human thermal comfort by the smart clothing

Generally, human thermal comfort depends on combinations of clothing structure and chemical nature of fibers, external conditions and factors related to wearer. Thermal comfort of a clothing system is associated with thermal balance of body and its thermoregulatory responses to the dynamic interactions with the clothing and the environment, and can be quantified in terms of Met and Clo units. One of the important functions of clothing is to provide adequate thermal comfort for wellness and high performance. To do this research, clothing with an integrated human microclimate regulating electrical system has been developed. The clothing contains: Peltier elements, which provide cooling effect; electronic control system with heat sensor – thermistor, which controls the optimal operating parameters, and energy source. The aim of experiments is to verify, how the cooling system, integrated in the clothes, influences indicators of the human microclimate. For this reason, the experiments of wearing by the appropriate operating conditions are carried out by measuring temperature changes in different locations in space between the body and clothes during activities. The analysis of experimental results reveals the system's operational efficiency as well as the negative impact of non-evaporative materials on the possibility of vapour removal through the garment surface.

Study of a Micro Thermal Environment of a Personal Air-Conditioning

In a highly developed living, people are always looking for a comfortable indoor environment with minimum energy use. Regional air conditioning mechanism (RACM) can create a personal thermal comfort control in a workroom which can contribute to save air-conditioning energy. In this study, we analyze the airflow circulation cell of the RACM with varied inlet port opening and inlet port position dimensions using the computational fluid dynamics (CFD) technique. We created a RACM, two workstations, lightings, and a cabinet in a 3-dimensional room. The fluid was assumed to be Newtonian, unsteady, and incompressible. A Bossinesq approximation was determined in order to consider the buoyancy effect. We examined the effects of the inlet port opening and inlet port position on airflow circulation establishing process. Air temperatures along the various midline of the occupied zone were predicted and compared for a range of inlet port opening and inlet port position by using nondimensional form. We also showed the occupied zone temperature at various planes in the workroom. Results will indicate the suitable inlet port opening and inlet port position for maintaining individual satisfied occupants’ requirements and improving energy saving potential.

Thermal Comfort Control Based on a Simplified Predicted Mean Vote index

Temperature restriction in indoor environment is a simple way of saving energy; however, it may cause discomforts to the people in such an indoor environment. The discomfort is aggravated when the environments of different rooms cannot be controlled individually. Furthermore, the discomfort is intensified during the intermittent seasons. Thermal comfort is estimated by the Predicted Mean Vote (PMV) model based on six parameters. This is a complex procedure and has limitations because a number of measurement indices have to be known. Hence, we analyzed the major variables of PMV and simplified the parameters in order to implement the model without incurring additional cost or installing equipment such as sensors. In addition, we compared the simplified PMV control with a control based on room temperature. The simplified PMV control realizes 7.0% more thermal comfort and 5.6% more energy reduction than those achieved by room temperature control, especially in the intermittent operation period.

Indoor Human Thermal Comfort Optimal Control with Desiccant Wheel Cooling System

Human thermal comfort is an important concern in the energy management of commercial buildings. Human thermal comfort research focuses mostly on the temperature control or the humidity control while based on human thermal comfort index control is ignored. In this paper, an optimal human thermal comfort control model (OHTCM) for a desiccant wheel cooling system is presented for the dehumidification and cooling of a commercial building in summer seasons. The OHTCM has two objectives. The first objective of the OHTCM is to minimize the predicted percentage of dissatisfied (PPD) which is the human thermal comfort index, and the second objective is to minimize the power consumption of the desiccant wheel cooling system. Model predictive control (MPC) strategy has the ability to handle constraints, being able to use simple models and to change controls dynamically in terms of temperature, humidity and air velocity changes, which makes it very practical to use in indoor human thermal comfort control problem. Therefore, MPC strategy is applied to implement the optimal operation of the desiccant wheel cooling system during working hours of the commercial building. To illustrate the practical applications of the MPC strategy, the optimization of the desiccant wheel cooling system in a commercial building of South Africa is studied.