Thermal Comfort Analysis in Dormitory Room by Combined MVHR-Fan Coil

A one room mechanical ventilation with heat recovery (MVHR) unit was tested on experimental bedding for survival of house dust mites and Der p 1 allergen levels in simulated bedroom conditions (February‐April 1995). Its effectiveness was also tested in a real bedroom in daily use, during the mild and damp British winter from December 1994‐February 1995. Experimental beds were artificially contaminated with approximately 1000 mites and samples obtained, using sticky traps to collect mobile‐mites, at 4 weeks and 8 weeks incubation in ventilated and non‐ventilated rooms. A sample of the mite population was also taken from a single‐bed in daily use, before and after running the MVHR unit. Results were compared longitudinally as well as transversely with those from non‐ventilated rooms. The MVHR unit in the real bedroom was run at a trickle operation mode, approximately 0.75 air changes/h, but air exchange in the experimental bedroom was maintained at 3.5 air changes/h by operating at the boost level. Data on ...

A field study on adaptive thermal comfort in Spanish primary classrooms during summer season

Purpose – Concern of the deterioration of indoor environmental quality as a result of energy efficient building design strategies is growing. Apprehensions of the effect of airtight, super insulated envelopes, the reduction of infiltration, and the reliance on mechanical systems to provide adequate ventilation (air supply) is promoting emerging new research in this field. The purpose of this paper is to present the results of an indoor air quality (IAQ) and thermal comfort investigation in UK energy efficient homes, through a case study investigation. Design/methodology/approach – The case study dwellings consisted of a row of six new-build homes which utilize mechanical ventilation with heat recovery (MVHR) systems, are built to an average airtightness of 2m3/m2/hr at 50 Pascal’s, and constructed without a central heating system. Physical IAQ measurements and occupant interviews were conducted during the summer and winter months over a 24-hour period, to gain information on occupant activities, perception of the interior environment, building-related health and building use. Findings – The results suggest inadequate IAQ and perceived thermal comfort, insufficient use of purge ventilation, presence of fungal growth, significant variances in heating patterns, occurrence of sick building syndrome symptoms and issues with the MVHR system. Practical implications – The findings will provide relevant data on the applicability of airtight, mechanically ventilated homes in a UK climate, with particular reference to IAQ. Originality/value – IAQ data of this nature is essentially lacking, particularly in the UK context. The findings will aid the development of effective sustainable design strategies that are appropriate to localized climatic conditions and sensitive to the health of building occupants.

Advancing building bioclimatic design charts for the use of evaporative cooling in the composite climate of India

Purpose This study aims to provide a detailed spatiotemporal analysis of indoor thermal comfort by introducing a novel approach for reconstructing air temperature and air velocity fields. Design/methodology/approach Strategic deep neural networks and refined computational fluid dynamics (CFD) were employed to reconstruct the air temperature and air velocity fields across five cases with varying window configurations and air diffusers. The predicted mean vote (PMV) and predicted percentage of dissatisfied (PPD) metrics, calculated based on the simulated air temperature and air velocity, were used to assess thermal sensation. Findings The refined CFD simulation approach could reveal a nonuniform distribution of air temperature, while the proposed deep neural networks enable precise and rapid reconstruction of the global temperature and air velocity distribution using only limited measurement data as input and eliminating the need for case-specific model fine-tuning. The spatiotemporal analysis of thermal comfort profiles reveals a nonuniform distribution of thermal comfort within the case office rooms, with cooler areas observed in the central middle of the space. This nonuniform thermal comfort profile may be influenced by design features such as window configurations and air diffusers, with a higher temperature observed near the window facades and the top ceiling. Research limitations/implications The proposed reconstruction methods are scalable to real-world empirical cases with various configurations, enabling accurate and efficient indoor environment modeling, which can further facilitate the design and optimization of real-time heating, ventilation and air conditioning control systems. The simulated spatiotemporal thermal comfort profile can serve as a valuable reference for building managers in climate regulation and space allocation, promoting a comprehensive approach to enhancing energy efficiency while maintaining thermal comfort. Originality/value This research presents a novel approach for reconstructing air temperature fields using deep neural networks, which require minimal data volume and are independent of boundary conditions, coupled with a refined CFD method that reveals the spatiotemporal patterns of air temperature and air velocity rather than relying on statistical mean estimations. Together, these techniques enable more detailed, dynamic and accurate analyses of thermal comfort.

This report briefly summarizes the current state of the HLRB II project h005y which focuses on the interactive simulation and local assessment of indoor thermal comfort. The research group therefore develops a Computational Steering Environment (CSE) which consists of a parallel CFD kernel, a fast 3D mesh generator and a virtual reality-based visualization and steering component. The numerical method is based on a lattice Boltzmann algorithm with extensions for simulations of turbulent convective flows. Utilizing high-performance supercomputing facilities, the CSE allows for modifying both the geometric model and the boundary conditions during runtime coupled with the immediate update of results. This is made possible by a space-tree based partitioning algorithm that facilitates the meshing of arbitrarily shaped, complex facet models in a matter of just a few seconds computing time. Ongoing developments address the integration of a radiation solver, a human thermoregulation model and a local thermal comfort model.

Indoor air quality and thermal comfort studies of an under-floor air-conditioning system in the tropics

The ventilation heat loss in a typical unimproved UK dwelling is approximately equal to the conduction loss; therefore draught-proofing measures should form part of any energy refurbishment package.This will improve the building's air permeability but risks incurring additional energy costs associated with the need to provide controlled ventilation to maintain indoor air quality.This paper aims to determine the point at which the air permeability of the building improves the energy performance by enough to justify the increase in energy associated with the installation of mechanical ventilation with heat recovery (MVHR).A 1930's style semi-detached house, representative of a large proportion of solid wall dwellings in the UK, has been improved by a package of measures including MVHR.The building air tightness plays a critical role in reducing the building energy consumption and CO 2 emissions.

ABSTRACTDespite growing concerns about overheating, a lack of evidence exists on the scale of the problem, particularly in contemporary UK housing. This paper presents the results of a meta-analysis of indoor temperatures in selected low-energy housing. Temperature data recorded at five-minute intervals in 60 dwellings across 19 demonstration projects (2012–14) were collated and analysed to investigate the prevalence of overheating. Findings evidence high summertime temperatures, with 27% of living rooms exceeding 28°C during August. Based on the Chartered Institution of Building Services Engineers (CIBSE) threshold of 5% annual occupied hours > 25°C, 57% of bedrooms and 75% of living rooms were classified as having overheated. Overall, 30% of living rooms exceeded the adaptive comfort threshold of > 3% occupied hours ΔT ≥ 1 K. The results suggest a fundamental relationship between ventilation and indoor temperatures. The higher minimum and average summertime temperatures observed in mechanical ventilation with heat recovery (MVHR) homes (p < 0.05) and lower temperature range (p < 0.001) suggest the need for greater attention to adequate summertime ventilation provision in airtight homes. The results demonstrate a high prevalence of overheating in exemplary housing, indicating the need for greater efforts to ensure the effective implementation of strategies to minimize overheating and improve ventilation in low-energy homes.

This study has focused on evaluating the financial potential of wastewater and geothermal heat recovery systems in a multi-family building. The recovered heat was used to improve the performance of mechanical ventilation with heat recovery (MVHR) system during the coldest days in central Sweden. The main issue, which was targeted with these solutions, was to reduce frost formation in the system and hence increase its thermal efficiency. By looking at the life cycle cost over a lifespan of 20 years, the observed systems were being evaluated economically. Furthermore, statistical analyses were carried-out to counter the uncertainty that comes with the calculation. It was found that the studied wastewater systems have a high possibility of generating savings in this period, while the one fed by geothermal energy is less likely to compensate for its high initial cost. All designed systems however, managed to reduce operational cost by 35-45% due to lower energy usage.

Analysis of UK domestic building retrofit scenarios based on the E.ON Retrofit Research House using energetic hygrothermics simulation – Energy efficiency, indoor air quality, occupant comfort, and mould growth potential

This study focuses on enhancing indoor air quality and thermal comfort in indoor swimming pool facilities through the investigation of ventilation system configurations. Creating a comfortable and healthy environment in these facilities is crucial for the well-being of occupants and overall operational efficiency. The performance of the ventilation system significantly influences user comfort, energy consumption, and air quality. This research aims to analyze the impact of different ventilation system configurations on indoor air quality and thermal comfort parameters using computational fluid dynamics (CFD) simulations.To achieve the research objectives, CFD simulations were conducted using ANSYS Fluent ®, a widely used commercial CFD package. The simulations involved solving the governing equations for continuity, momentum, energy, and species transport, along with employing the k-epsilon turbulence closure model. A high-resolution mesh with over 5.6 million elements accurately captured the flow regimes and related phenomena.The study investigated various aspects of ventilation system configurations, including the placement and design of inlets and outlets, airflow rates, and distribution patterns. Evaluations were made based on key performance indicators such as indoor air quality parameters, thermal comfort indices, and energy efficiency metrics. Comparisons were made between different configurations to identify the most effective strategies for enhancing indoor air quality and thermal comfort.The findings of the study demonstrate the importance of ventilation system design in achieving optimal indoor air quality and thermal comfort in indoor swimming pool facilities. The results indicate that specific configuration choices, such as the use of circular inlets in the ceiling for improved spectator comfort and rectangular inlets in the side walls for better performance in the swimming pool area, can significantly impact thermal conditions and air distribution. Additionally, the study emphasizes the need for appropriate inlet grille height to ensure adequate air mixing and thermal comfort.The outcomes of this research provide valuable insights for architects, engineers, and facility managers involved in the design, construction, and operation of indoor swimming pool facilities. By understanding the impact of different ventilation system configurations, stakeholders can make informed decisions to optimize indoor air quality, thermal comfort, and energy efficiency. Ultimately, this research contributes to the development of sustainable and comfortable indoor swimming pool environments that cater to the needs of occupants and enhance their overall experience.

Local thermal comfort and draught rate has been studied widely. There has been more meaningful research performed in controlled boundary condition situations than in actual work environments involving occupants. Thermal comfort conditions in office buildings in Estonia have been barely investigated in the past. In this paper, the results of thermal comfort and draught rate assessment in five office buildings in Tallinn are presented and discussed. Studied office landscapes vary in heating, ventilation and cooling system parameters, room units, and elements. All sample buildings were less than six years old, equipped with dedicated outdoor air ventilation system and room conditioning units. The on-site measurements consisted of thermal comfort and draught rate assessment with indoor climate questionnaire. The purpose of the survey is to assess the correspondence between heating, ventilation and cooling system design, and the actual situation. Results show, whether and in what extent the standard-based criteria for thermal comfort is suitable for actual usage of the occupants. Preferring one room conditioning unit type or system may not guarantee better thermal environment without draught. Although some heating, ventilation and cooling systems observed in this study should create the prerequisites for ensuring more comfort, results show that this is not the case for all buildings in this study.

This work seeks to analyze the thermal comfort of the occupants in a large building of Commerce and Services, integrating measures of assessment and energy efficiency promotion. The building is still in the construction phase and at its conclusion, will correspond to a supermarket located in the Central region of Portugal. For the evaluation of thermal comfort, Fanger’s methodology was used, where the Predicted Mean Vote (PMV) and Predicted Percentage of Dissatisfied (PPD) were calculated based on a detailed analysis of the environmental variables. These are essential to obtain, namely, mean air velocity, mean radiant temperature, mean air temperature and relative humidity. The other crucial variables are the metabolic rate and the thermal clothing resistance. The simulations necessary for the thermal comfort assessment were performed in ANSYS Fluent, in order to minimize the energy consumption in the cold thermal zone of the building, the sales area with frozen and chilled food, by means of reducing the inflow of air, without compromising thermal Comfort. The final results showed that the reduction of the amount of air to be inflated did not compromise the thermal comfort of the occupants. The Computational Fluid Dynamics (CFD) methodology allowed the creation of comfort maps, albeit for a single zone due to computational limitations. According to the results, the most comfortable zone was located right below the air insufflation with the summer being a more comfortable season. In winter, the main problem detected was the cold located near the floor.

Analysis of thermal comfort and indoor air flow characteristics for a residential building room under generalized window opening position at the adjacent walls