Thermal Comfort Of Users Research Articles

Impact of Urban Green Spaces on Outdoor Thermal Comfort and Psychological Behavior of Users during the Hottest Period in Biskra City

Impact of Urban Green Spaces on Outdoor Thermal Comfort and Psychological Behavior of Users during the Hottest Period in Biskra City

Impact of Urban Green Spaces on Outdoor Thermal Comfort and Psychological Behavior of Users during the Hottest Period in Biskra City

Impact of Urban Green Spaces on Outdoor Thermal Comfort and Psychological Behavior of Users during the Hottest Period in Biskra City

The influence of envelopes in the thermal performance of residential buildings, from the perspective of bioclimatic architecture

Energy efficiency measures (EEMs) and their impact on the thermal performance of buildings as well as on the user's thermal comfort, have become the focus of several studies. Bioclimatic strategies can contribute to improving thermal performance while increasing indoor thermal comfort for users. This paper aims to verify the bioclimatic potential of two types of dwellings in three Brazilian cities. The first one is the baseline, with basic construction systems. The other includes EEMs. The method consists of the verification of bioclimatic potential by psychometric charts for indoor and outdoor conditions. The results show significant indoor discomfort caused by heat in both dwellings—thermal comfort conditions during more than 95% of annual hours in Manaus, and during 85% in São Paulo. Therefore, energy efficiency strategies such as shading, ventilation and HVAC systems are necessary to promote thermal comfort conditions in hot climates.

A spectrally-resolved method for evaluating the solar effect on user thermal comfort in the near-window zone

The effects of solar radiation play an important role in human thermal comfort. When predicting the shortwave solar thermal effect through windows on indoor occupants, the spectra of solar irradiance, window transmittance, and skin absorptance must be considered. This work proposes a spectrally-resolved method for predicting this effect on occupants facing windows in the near-window zone. The vertical and horizontal penetration of direct solar irradiance is also characterized. In this work, we quantify the differences in resultant thermal comfort estimations between the spectrally-resolved and conventional constant-value methods through a series of simulated conditions on different days of the year and at different times of day, as well as with various window orientations and sky conditions. Through numerical analysis, we investigate the effects of and interactions among the various parameters and demonstrate situations in which the spectrally-resolved method is necessary. By understanding the necessity of the spectrally-resolved method and the influence of variations in spectral and energy intensities, we are able to make preliminary judgments regarding when the spectrally-resolved method is essential to making relatively accurate predictions of indoor thermal comfort in the near-window zone. This research provides a new and fundamental numerical method that can be used to take the spectral characteristics of solar energy, windows, and human skin into account for more accurate user thermal comfort analyses in the near-window zone.

Simulation Method to Assess Thermal Comfort in Historical Buildings with High-Volume Interior Spaces—The Case of the Gothic Basilica of Sta. Maria del Mar in Barcelona

Concerns about the energy performance of heritage buildings have grown exponentially over the last decade. However, actions have been limited to reducing energy consumption and carbon emissions. Another perspective must be studied—the thermal comfort of users, for human welfare and health. The assessment of thermal comfort inside a historic building with a single, large volume interior space is not easy. The complexity increases if the building has high cultural protection and its envelope cannot be altered, to preserve its historical values. This paper focuses on this kind of building and describes a dynamic simulation method used to assess thermal comfort in the Gothic Basilica of Sta. Maria del Mar in Barcelona. The basilica’s interior thermal conditions are intense cold during the winter and extreme heat and sultriness during the summer. Several simulation scenarios were considered to highlight the failure to obtain thermal comfort for users through passive strategies during the summer period. When all the factors are considered, the only valid strategy is to introduce an active system. This must be minimized according to three criteria: reducing operational periods, considering just the air volume next to users and adjusting the level of comfort requirement.

Sustainable energy performance in Brazilian social housing: A proposal for a Sustainability Index in the energy life cycle considering climate change

The main goal of this research is the proposal of an integrated approach, considering sustainability indicators related to energy life cycle of the building, for evaluation of energy efficiency measures with adaptation to climate change in Brazilian social housing projects. A Sustainability Index in the Energy Life Cycle was proposed that includes indicators associated to environmental, energy, economic aspects and user thermal comfort. A case study applied in the city of São Paulo, considered a representative project of the sector and cases with energy efficiency adaptation measures for three climate scenarios, considering climate change. The integrated approach highlighted the importance of the initial selection of materials, considering their associated impacts as well as the thermal and energy performance of the building during its life time, and the importance of climate change for the operational phase of the building. With the Sustainability Index in the Energy Life Cycle, large reductions were obtained comparing cases with adaptation measures to current practice. Results of this research contribute to improve project’s decisions with the incorporation of a holistic approach for the projects that are being produced for the housing deficit, considering better energy performance and lower resource consumption for users and the country in the long term.

Numerical Study of the Performance of a Double-Insulated Barbecue Oven: Implication for Energy Savings and Thermal Comfort

This work is devoted to a numerical study of the performance of a double insulated barbecue oven using terracotta bricks and plywood. The numerical methodology is based on the nodal method and the heat transfer equations have been established by performing an energy balance on each node. The equations obtained were then discretized using an implicit finite difference scheme and solved by the Gauss algorithm. The numerical results validated by the experiment show that this double insulation considerably reduces the energy losses through the walls of the oven. However, the addition of plywood does not significantly change the energy savings compared to simple terracotta insulation but does drop the external wall temperatures. Thus, for 4 cm of thickness of terracotta bricks and 1 cm of plywood, the energy savings (compared to the non-insulated oven) are of the order of 70% and the temperature of the outer walls of the oven does not exceed not 60°C, which ensures better thermal comfort for users.

Comparative analysis of user comfort and thermal performance of six types of vernacular dwellings as the first step towards climate resilient, sustainable and bioclimatic architecture in western sub-Saharan Africa

The purpose of this study is to assess thermal comfort conditions in vernacular dwellings in western sub-Saharan Africa. The paper identifies six vernacular and low-tech building typologies specific for selected countries. Comparative analysis of user comfort and thermal performance of case studies, representative for each typology was carried out, as the first step towards climate resilient, sustainable and bioclimatic architecture in the region of the investigation. The measurements of temperature, relative humidity, indoor air quality and daylighting as well as the user satisfaction survey were performed in February 2019 and repeated in August 2019. It was determined that during the hot and dry season, the indoor temperatures of 26–30 °C were achieved in traditional dwellings (Typologies I-IV) and accepted by 60–70% of inhabitants, while in ‘modern houses’ (Typology VL2 and VI) the level of user thermal comfort was significantly lower (only 20% felt comfortable). During the colder wet season 90% of users felt comfortable in vernacular dwellings and only 50% in ‘modern houses’. High levels of CO2 concentrations were detected in dwellings with tight envelopes (1800–1900 ppm) due to the lack of adequate ventilation. In pursue of solution various air exchange rates were examined to check how they comply with the user thermal comfort perception. It was found that the optimal ventilation should provide the air exchange rate of 0.5 VR/h which allows to fulfil minimal demands of ISO and ASHRAE standards. The study established the baselines for sustainable, bioclimatic, affordable housing model for western sub-Saharan Africa.

Optimal battery utilization for energy management and load scheduling in smart residence under demand response scheme

Smart residences that could optimally integrate the actions of all their components are essential in the smart grid architecture. This paper proposes a mixed-integer linear programming (MILP) based model of a single residence that optimally operates the residential appliances and manages the energy received from the Distributed Energy Resources (DERs) apart from the utility grid according to the day-head Time of Use prices. To achieve this, an Energy Management and Load Scheduling System (EMLSS) has been incorporated into the residence. Further, the user thermal comfort was maintained by optimally operating the air conditioner in coordination with a dehumidifier to keep the indoor temperature and relative humidity within the desired limits. For observing the EMLSS’s operation under the intermittent weather conditions, the simulation of the MILP model was conducted for 26 different days of the year. Using these days’ results, an annual study was conducted whose results were input into the Rainflow Cycle Counting algorithm for assessing the capacity degradation of the residential Battery Energy Storage System (BESS) until its End of Life (EoL). The energy expenditure evaluation conducted until the BESS’s EoL, confirmed the effectiveness of the EMLSS in reducing the replacement costs of the old BESS battery. • Residential expenditure over multiple years evaluated until the battery’s End of Life. • Capacity degradation of the battery assessed using Rainflow Cycle Counting algorithm. • EMLSS optimally manages the DERs and loads in a single residence. • EMLSS found effective in reducing the replacement costs of the old BESS battery.

Design of Supervisory Model Predictive Control for Building HVAC System With Consideration of Peak-Load Shaving and Thermal Comfort

This paper proposes a design of a supervisory model predictive controller for a heating-ventilation-air-conditioning (HVAC) control system. The control objective is to minimize the operating cost and take into account of electrical load shaving and thermal comfort of users. To ensure that thermal comfort is well regulated, we utilize the Predicted Mean Vote (PMV) as an indicator and determine an acceptable bound of a desired set-point temperature. The control design consists of two layers, namely, a supervisory control (SC) layer and a model predictive control (MPC) layer. For the SC layer, we explore a configuration for the SC layer including the choice of predesign controller, the analysis of steady-state response, and the analysis of the possible range of the set-point temperature. We incorporate the effect of set-point temperature, air velocity, outside air temperature, heat load inside zone onto the HVAC electrical power. Then, we search for an optimal profile of the set-point temperature that minimizes a weighted sum of a total operating cost (TOC) and a thermal comfort cost (TCC). Moreover, exploration of trade-off between TOC and TCC helps us to achieve both control objectives efficiently. For the MPC layer, we formulate the control design with the objective of tracking the optimal set-point temperature and minimizing the control inputs. We apply the proposed control design to a complex dynamical model of HVAC system with volumetric flow rate, electrical power of heat exchanger, and removed moisture as control variables. When the allowable PMV of the zone is specified within 0.5, the TOC of the proposed supervisory MPC is reduced by 12.46% compared with that of the nominal operation. The maximum electricity demand of HVAC system is reduced by 13.43% and the electrical power profile is smoothly shaved under the proposed control scheme. Furthermore, the zone relative humidity is well regulated which corresponds to the assumption in the supervisory control.

Optimal Dispatching of Distribution Network Considering System Flexibility and User Thermal Comfort

To solve the problem that the uncertainty of distributed generation output seriously affects the safe and stable operation of distribution network, heat load, as a potential flexibility resource, can improve flexibility and eliminate system fluctuation without increasing new equipment. Therefore, an optimal dispatching model of the distribution network is proposed in this paper to improve the system flexibility while ensuring human comfort and operation economy. Firstly, the virtual energy storage model and human thermal comfort model of electric water heater (EWH) and air conditioning (AC) load are established. Secondly, a flexibility evaluation method is proposed based on the virtual energy storage of heat load. Furthermore, to decrease comprehensive operation cost and increase system flexibility, a two-stage distributed robust optimal dispatching model, which considers three kinds of flexible resources of EWH, AC and gas turbine (GT) is constructed. Then, the norm is used to constrain the uncertainty probability of wind turbine and photovoltaic output, and the column and constraints generation (C&CG) algorithm is used to solve the model. Finally, a simulation is given to verify the effectiveness of the proposed method in improving the flexibility of distribution network.

Optimal scheduling method based on building virtual energy storage equivalent battery

In this paper, an optimal scheduling method based on building virtual energy storage equivalent battery is proposed. Firstly, the thermal load prediction model is built based on the thermodynamic model, and then the equivalent battery model of virtual energy storage is established by combining with inverter air conditioning system model. Then, with the goal of minimizing the user’s electricity cost, considering the constraints of energy storage state and charging and discharging power of equivalent battery model, an optimal scheduling method of building virtual energy storage equivalent battery is constructed. The results show that the proposed method can predict the building thermal load, update the building virtual energy storage equivalent battery parameters, formulate the corresponding optimal scheduling strategy, and reduce the electricity cost of users for heating on the premise of ensuring the thermal comfort of users.

Design Guidelines for Thermal Comfort and Energy Consumption of Triple Glazed Fluidic Windows on Building Level

AbstractThere has been a growing trend for buildings with large glazing size. As a trade‐off, this comes with enhanced solar heat input and/or reduced thermal insulation. Several approaches are being followed to reduce the energy consumption in these buildings, including the prolific field of smart windows. In a previous report, a fluidic window device for thermal harvesting and air‐conditioning was introduced. Using this example, the impact of a building's window‐to‐wall ratio on the triple glazed fluidic window's energy consumption and user thermal comfort is evaluated, providing design guidelines for large‐scale implementation of such smart windows with real‐world buildings. The analysis shows that the proposed window design reduces the primary energy demand as compared to using a conventional air‐conditioning system. Building simulation results indicate that the system enables satisfying thermal comfort for buildings with different window‐to‐wall ratios. Although a higher window‐to‐wall ratio improves the heat pump efficiency, it requires more heating and cooling energy. On‐device photovoltaic modules may be used for changing this relationship. In this case, the proposed device may become self‐sufficient once the transfer efficiency is high enough. It is argued that similar considerations should be applied to other types of smart window technologies.

Numerical simulation and study of thermal characteristics of a lightweight floor heating system

The use of underfloor heating systems is an effective way to achieve thermal comfort for users in energy-efficient buildings. There are two kinds of such systems: traditional and dry-assembled. The first type is researched more deeply than the second one. The paper presents theoretical studies of the thermotechnical parameters of a water underfloor dry-assembled heating system. The design of the underfloor dry-assembled heating system, considered in the work, consists of a heat insulation (expanded polystyrene), on which the pipes of the heating system are located, in contact with an aluminum heat distribution plate. The system is covered with floor finishing. The calculation for a stationary operating mode of the floor heating system was carried out on the basis of a system of equations for momentum and energy. The model was validated using the results of experimental studies. The calculation results cause some overestimation of the experimental data, possibly, beecause of deviations in thermotechnical characteristics of materials. But the simulation model correctly estimates the behaviour of the system at change of its parameters. The paper concludes that this configuration of the underfloor heating system can be used in heating systems for residential and non-residential premises. The aluminum heat distribution plate significantly affects the heat transfer processes in the system. Due to the plate, the heat flux is made uniform in the plane of the floor surface, which has a positive effect on heat distribution and reduces thermal tension in the finish coating. The use of ceramic tiles increases the overall heat exchange efficiency of the system with the room air. An increase in the thickness of the expanded polystyrene board increases the value of the heat flux from the surface of the heated floor. An increase in the flow rate and temperature of the heat carrier also cause an increase in the density of heat flux from the floor surface.

User Thermal Comfort in Historic Buildings: Evaluation of the Potential of Thermal Mass, Orientation, Evaporative Cooling and Ventilation

The study investigated the level of thermal comfort in historical buildings located at a relatively high altitude in the Arabian Desert of Saudi Arabia. The study focused on the impact of the use of thermal mass and orientation on the level of thermal performance at Shubra and Boqri Palaces. Qualitative and quantitative analyses were used in this study, including a questionnaire interview with architecture experts living at the relatively high altitude of Taif city, to obtain data and information from local experts. The computer software TAS EDSL was used along with on-site equipment, such as thermal imaging cameras and data loggers, to observe the physical conditions of the building in terms of its thermal performance. The study revealed that the experts’ age and years of experience were important aspects while collecting data from them during the survey. The use of thermal mass had a slight impact on the indoor air temperature as well as the energy consumption, but it helped in providing thermal comfort. Use of ventilation can improve thermal comfort level. Evaporative cooling technique has a considerable impact on reducing indoor air temperature with 4 °C drop, improving the thermal comfort sensation level. The novelty of this work is that, it links the outcomes of qualitative results of experts with field monitoring as well as computer modelling. This can contribute as method to accurately collect data in similar case studies.

Can we learn from heritage buildings to achieve nearly zero energy building and thermal comfort? A case study in a hot climate

ABSTRACT Heritage buildings were built in a period when energy equipment for cooling and heating did not exist. This research focuses on the way in which we could benefit from such constructions to impact today's buildings and society. The investigation will consider a number of elements such as thermal mass, day-lighting and thermal comfort in comparison with a new simulated building which has the same design as the Heritage one. The research was conducted using the energy simulation tool TAS EDSL and on site measurement. In addition to that, an advanced thermal imaging camera was used in the study of physical characteristics of the building. The study revealed that applying methods of Heritage buildings to modern buildings, such as the use of thermal mass and natural ventilation, can have a considerable impact on energy consumption and thermal comfort for users. It can reduce indoor temperature up to 5°C. It was also found that the use of natural ventilation is linked to indoor thermal comfort. Large area of glazing is recommended to be used in such region when it is applied in the proper way.

Time-Scale Economic Dispatch of Electricity-Heat Integrated System Based on Users’ Thermal Comfort

The electricity-heat integrated system can realize the cascade utilization of energy and the coordination and complementarity between multiple energy sources. In this paper, considering the thermal comfort of users, taking into account the difference in dynamic characteristics of electric and heating networks and the response of users’ demands, a dispatch model is constructed. In this model, taking into account the difference in the time scale of electric and thermal dispatching, optimization of the system can be improved by properly extending the thermal balance cycle of the combined heat and power (CHP) unit. Based on the time-of-use electricity prices and heat prices to obtain the optimal energy purchase cost, a user demand response strategy is adopted. Therefore, a minimum economic cost on the energy supply side and a minimum energy purchase cost on the demand side are considered as a bilevel optimization strategy for the operation of the system. Finally, using an IEEE 30 nodes power network and a 31 nodes heating network to form an electricity-heat integrated system, the simulation results show that the optimal thermal balance cycle can maximize the economic benefits on the premise of meeting the users’ thermal comfort and the demand response can effectively realize the wind curtailment and improve the system economy.

Performance analysis of light shelves in providing visual and thermal comfort and energy savings in residential buildings

Using light shelves (LSs) is one of the passive-enhancement methods for energy saving and providing better thermal comfort conditions of the building users. The goal of this research is to create a consistent daylight environment that improves the visual and thermal comfort of users in buildings. Comfort effects on the four fronts of a building (in the Pars residential complex of Mashhad city in Iran as a case study) are investigated. Five types of LSs are suggested for improving the building’s thermal and visual conditions. Then, the illuminance analysis is performed for the building with and without the LSs. Horizontal and vertical LSs are considered in building to enhance visual quality and uniformity of daylight in the building space. According to the highest and lowest light intensity in the investigated spaces, the LS that provides optimal visual conditions for space is selected. Then, the role of optimum LS in thermal comfort and energy indicators (heating, cooling, and electricity) has been investigated and compared with the base situation. Analyzing the results reveals that using the optimal LS causes an annual average improvement of 18%, 11%, and 7% in the demand for heating, cooling, and electricity, respectively, of the building throughout the year.

Effects of future climate change on the preservation of artworks, thermal comfort and energy consumption in historic buildings

Climate change will affect the indoor temperature of historic buildings, impacting the preservation of artworks and the thermal comfort of users, and possibly leading to increased energy consumption. These buildings generate more emissions than new buildings and in most European countries, preservation principles take precedence over energy efficiency and the reduction of emissions. This research is a key topic for the mitigation of climate change and proposes a method for assessing the impact of climate change on the preservation of artworks, thermal comfort, and energy consumption. An experimental method was followed, combining analytical formulations, on-site measurements, and Heating, Ventilation and Air Conditioning systems in order to identify the adequate hygrothermal parameters for historic buildings. The climate change scenario predicted for 2050 was based on projected temperature variation. The case studies were Baroque churches, historic buildings located in the south of Europe. Data obtained from a monitoring campaign carried out in these churches was used to validate dynamic simulation models. The churches analysed showed an increase in cooling demand and a decrease in heating demand. Furthermore, in order to ensure human comfort and the preservation of artworks, it was necessary to implement active systems in operation for 12-hour periods. These results suggest an energy overconsumption, as the energy consumption for human comfort and artwork preservation was 50% higher than the energy consumption of active systems for the preservation of valuable historic objects. In addition, the annual energy consumption decreases for future scenarios for 2050 in the case of artwork preservation and thermal comfort, but increases by almost 15% for the preservation of works of art due to higher level relative humidity. Before historic buildings can be adapted, it is essential to understand the influence of the future climate on their design, construction, and environmental conditions.

Estudo de Torre de Vento: Ensaio em Túnel de Vento em Edificações Residenciais

A adoção da ventilação natural em substituição à ventilação mecânica pode contribuir para a redução do consumo de energia elétrica das residências. Dentre as soluções possíveis está a utilização de torres de vento, solução arquitetônica original milenar do povo persa, para o condicionamento de ambientes internos, reduzindo o consumo de energia com ganhos significativos no quesito do conforto térmico. As torres de vento aplicadas às edificações podem funcionar como consequência da diferença de pressão do vento que incide na fachada ou devido à variação de temperatura: o ar frio entra por uma abertura, refrigerando o interior do local e empurrando o ar quente para fora do edifício. O desenvolvimento do trabalho foi dividido nas seguintes etapas metodológicas: 1) determinação dos modelos reduzidos, 2) definição dos parâmetros de ensaio, 3) programação de sensores e 4) ensaio em túnel de vento. Os resultados obtidos no túnel de vento permitiram avaliar a melhor configuração de torre de vento para cada caso, visando reduzir a temperatura interna dos ambientes. Além disso, foi possível concluir que a variação de temperatura de 0,5°C alcançada pode contribuir para a redução de consumo de energia elétrica e ao mesmo tempo preservar ou ampliar o conforto térmico dos usuários.