The Impact of Hybrid Ventilation on Thermal and Energy Performance in Hot and Humid Weather

2011 ◽  
Vol 199-200 ◽  
pp. 1505-1508
Author(s):  
Jia Fang Song
Keyword(s):  
Thermal Comfort ◽  
Natural Ventilation ◽  
Energy Performance ◽  
Simulation Software ◽  
Comfort Level ◽  
Air Velocity ◽  
Output Performance ◽  
Hybrid Ventilation ◽  
The Impact ◽  
Full Height

In this paper, the simulation software was applied to evaluate a hybrid ventilated combined mechanical and naturally ventilated (atrium area to be naturally ventilated) building. In order to understand the impact of the usage of natural ventilation on thermal comfort in atrium, we utilized TAS to simulate the air temperature and air velocity distribution for the atrium. A modeled three-storey commercial office building was used as the main subject of this analysis. To determine the thermal comfort level of the central atrium, Parameters will be set in such a way that the full height windows will be 100% open. Results were tabularized to determine and analysis the output of the simulation. Recommendations will be then given based on the output performance of the building.

The Application of Computer Simulations on one Commercial Building to Improve Energy Performance

2010 ◽  
Vol 171-172 ◽  
pp. 364-367
Author(s):  
Jia Fang Song
Keyword(s):  
Thermal Comfort ◽  
Energy Demand ◽  
Natural Ventilation ◽  
Ventilation System ◽  
Energy Performance ◽  
Comfort Level ◽  
Commercial Building ◽  
Simulation Tools ◽  
Output Performance ◽  
Support Software

This paper introduces the application of the TAS simulation support software to determine the energy performance in between a full mechanical ventilated building than that of a hybrid ventilated-- combined mechanical and naturally ventilated (atrium area to be naturally ventilated) building. A modeled three-storey commercial office building will be used as the main subject of this analysis. To determine the thermal comfort level of the central atrium, Parameters will be set in such a way that the full height windows will be 100% open. Results will be then tabularized to determine and analysis the output of the simulation. Recommendations will be then given based on the output performance of the building. In Tropics, it’s very difficult to achieve better thermal comfort in a naturally ventilated building. With the help of these simulation tools we can find whether natural ventilation is possible in this tropical climate in terms of thermal comfort, ventilation system and energy demand.

scholarly journals INFLUENCE OF MASS ‘U’ FORM IN LINE UP FORMATION TOWARDS AIR MOVEMENT ON SUPPORTING THERMAL COMFORT IN OUTSIDE SPACE OF APARTMENT LANDMARK RESIDENCE, BANDUNG

2019 ◽  
Vol 3 (04) ◽  
pp. 398-413
Author(s):  
Gabriela Marcella ; Nancy Yusnita Nugroho
Keyword(s):  
Thermal Comfort ◽  
Wind Velocity ◽  
Outer Space ◽  
Thermal Conditions ◽  
Simulation Software ◽  
Comfort Level ◽  
Air Velocity ◽  
Air Movement ◽  
The Masses ◽  
Mass Form

Abstract- Indonesia with the characteristics of tropical climate requires control in design to achieve thermal comfort both in outside space and inside space. One of the factors that can affect thermal comfort is the pattern of air movement and air velocity. Landmark Residence Apartment is one of the new apartments in Bandung, with mass ‘U’ form in line up of new partially awakened. The newly constructed 'U' mass formation forms the characteristic of the two different masses, the space side in the closed A mass with the characteristic of the centered space as well as the side in the open mass B. this apartment become an object of research to determine the factors of order and mass form to the characteristics of air movement as well as thermal comfort in the outside space as a space of activities in residents. The method used in this research is descriptive-quantitative with simulation software Flow Design to know the air movement and measurement of thermal comfort factor at the point of population and sample which have been determined. This thermal factor will be analyzed using CET Nomogram method, so it generates thermal comfort level in outer space which will be associated with order and mass form of apartment. By using analysis of air movement patterns and CET Nomogram, it is seen that thermal comfort level in the outside space Landmark Residence apartment is more affected by wind velocity. The mass 'U' form with the back to wind direction will produce high wind velocity on the outside space of the building's side, while on the inner side of the 'U' form will form the shadow of the wind and the pattern of turbulence air movement affecting the achievement of different thermal conditions. The 'U' mass sequence lined up can also cause air movement on the inner side of closed A mass not getting enough air movement compared to open mass B with better airflow pattern. The pattern of air movement on the inner side of mass A can be at any time higher when the wind velocity enters the gap between the masses.  Key Words: apartment, outside space, mass ‘U’ form in line up, air movement, thermal comfort.

scholarly journals Numerical analysis of the impact of natural ventilation on the Indoor Air Quality and Thermal Comfort in a classroom

2019 ◽  
Vol 111 ◽  
pp. 01023 ◽  
Author(s):  
George-Mãdãlin Chitaru ◽  
Andrei Istrate ◽  
Tiberiu Catalina
Keyword(s):  
Numerical Simulation ◽  
Air Quality ◽  
Thermal Comfort ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Natural Ventilation ◽  
Simulation Software ◽  
Educational Institutions ◽  
Research School ◽  
The Impact

Indoor air quality (IAQ) inside educational institutions is an important topic in the field of building and health research. School absenteeism and educational performance have been linked to poor air quality inside classrooms. A numerical simulation software has been used to test 5 different scenarios of natural ventilation during summer and winter. CO2 levels, air relative humidity, operative temperature and PMV were used as indoor air quality and thermal comfort indicators. Results have shown high CO2 and humidity levels when all windows are closed, and a variable improvement when different natural ventilations strategies are employed. A detailed procedure for the numerical simulation has been presented.

scholarly journals The Impact of Air Well Geometry in a Malaysian Single Storey Terraced House

2019 ◽  
Vol 11 (20) ◽  
pp. 5730 ◽  
Author(s):  
Pau Chung Leng ◽  
Mohd Hamdan Ahmad ◽  
Dilshan Remaz Ossen ◽  
Gabriel H.T. Ling ◽  
Samsiah Abdullah ◽  
...  
Keyword(s):  
Thermal Comfort ◽  
Air Temperature ◽  
Natural Ventilation ◽  
Heat Dissipation ◽  
Air Velocity ◽  
Wet Bulb Globe Temperature ◽  
Ventilation Technique ◽  
Ventilation Performance ◽  
Globe Temperature ◽  
The Impact

In Malaysia, terraced housing hardly provides thermal comfort to the occupants. More often than not, mechanical cooling, which is an energy consuming component, contributes to outdoor heat dissipation that leads to an urban heat island effect. Alternatively, encouraging natural ventilation can eliminate heat from the indoor environment. Unfortunately, with static outdoor air conditioning and lack of windows in terraced houses, the conventional ventilation technique does not work well, even for houses with an air well. Hence, this research investigated ways to maximize natural ventilation in terraced housing by exploring the air well configurations. By adopting an existing single storey terraced house with an air well, located in Kuching, Sarawak, the existing indoor environmental conditions and thermal performance were investigated and monitored using scientific equipment, namely HOBO U12 air temperature and air humidity, the HOBO U12 anemometer and the Delta Ohm HD32.3 Wet Bulb Globe Temperature meter. For this parametric study, the DesignBuilder software was utilized. The field study illustrated that there is a need to improve indoor thermal comfort. Thus, the study further proposes improvement strategies to the existing case study house. The proposition was to turn the existing air well into a solar chimney taking into account advantages of constant and available solar radiation for stack ventilation. The results suggest that the enhanced air well was able to improve the indoor room air velocity and reduce air temperature. The enhanced air well with 3.5 m height, 1.0 m air gap width, 2.0 m length was able to induce higher air velocity. During the highest air temperature hour, the indoor air velocity in existing test room increased from 0.02 m/s in the existing condition to 0.29 m/s in the hottest day with 2.06 °C air temperature reduction. The findings revealed that the proposed air well could enhance the thermal and ventilation performance under the Malaysia tropical climate.

scholarly journals Experimental Data and Simulations of Performance and Thermal Comfort in a Typical Mediterranean House

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3311
Author(s):  
Víctor Pérez-Andreu ◽  
Carolina Aparicio-Fernández ◽  
José-Luis Vivancos ◽  
Javier Cárcel-Carrasco
Keyword(s):  
Energy Efficiency ◽  
Thermal Comfort ◽  
Energy Demand ◽  
Natural Ventilation ◽  
Thermal Characterization ◽  
Energy Performance ◽  
Building Stock ◽  
Energy Demands ◽  
Dwelling House ◽  
Account Standard

The number of buildings renovated following the introduction of European energy-efficiency policy represents a small number of buildings in Spain. So, the main Spanish building stock needs an urgent energy renovation. Using passive strategies is essential, and thermal characterization and predictive tests of the energy-efficiency improvements achieving acceptable levels of comfort for their users are urgently necessary. This study analyzes the energy performance and thermal comfort of the users in a typical Mediterranean dwelling house. A transient simulation has been used to acquire the scope of Spanish standards for its energy rehabilitation, taking into account standard comfort conditions. The work is based on thermal monitoring of the building and a numerical validated model developed in TRNSYS. Energy demands for different models have been calculated considering different passive constructive measures combined with real wind site conditions and the behavior of users related to natural ventilation. This methodology has given us the necessary information to decide the best solution in relation to energy demand and facility of implementation. The thermal comfort for different models is not directly related to energy demand and has allowed checking when and where the measures need to be done.

scholarly journals Sensitivity Analysis of Occupant Preferences on Energy Usage in Residential Buildings

2021 ◽  
Author(s):  
Kaleb Pattawi ◽  
Prateek Munankarmi ◽  
Michael Blonsky ◽  
Jeff Maguire ◽  
Sivasathya Pradha Balamurugan ◽  
...  
Keyword(s):  
Sensitivity Analysis ◽  
Thermal Comfort ◽  
Residential Buildings ◽  
Electricity Consumption ◽  
Cost Savings ◽  
The United States ◽  
Comfort Level ◽  
Electrical Grid ◽  
Home Energy Management ◽  
The Impact

Abstract Residential buildings, accounting for 37% of the total electricity consumption in the United States, are suitable for demand response (DR) programs to support effective and economical operation of the power system. A home energy management system (HEMS) enables residential buildings to participate in such programs, but it is also important for HEMS to account for occupant preferences to ensure occupant satisfaction. For example, people who prefer a higher thermal comfort level are likely to consume more energy. In this study, we used foresee™, a HEMS developed by the National Renewable Energy Lab (NREL), to perform a sensitivity analysis of occupant preferences with the following objectives: minimize utility cost, minimize carbon footprint, and maximize thermal comfort. To incorporate the preferences into the HEMS, the SMARTER method was used to derive a set of weighting factors for each objective. We performed week-long building energy simulations using a model of a home in Fort Collins, Colorado, where there is mandatory time-of-use electricity rate structure. The foresee™ HEMS was used to control the home with six different sets of occupant preferences. The study shows that occupant preferences can have a significant impact on energy consumption and is important to consider when modeling residential buildings. Results show that the HEMS could achieve energy reduction ranging from 3% to 21%, cost savings ranging from 5% to 24%, and carbon emission reduction ranging from 3% to 21%, while also maintaining a low thermal discomfort level ranging from 0.78 K-hour to 6.47 K-hour in a one-week period during winter. These outcomes quantify the impact of varying occupant preferences and will be useful in controlling the electrical grid and developing HEMS solutions.

Fluid Flow and Heat Transfer Induced by a Window Air Conditioner Unit and Associated Thermal Comfort

2005 ◽  
Author(s):  
Hamza Begdouri ◽  
Luis Rosario ◽  
Muhammad M. Rahman
Keyword(s):  
Thermal Comfort ◽  
Comfort Level ◽  
Cfd Modeling ◽  
Air Distribution ◽  
Air Conditioner ◽  
Surface Areas ◽  
Air Supply ◽  
Office Rooms ◽  
Inlet Angle ◽  
The Impact

This study considers airflow simulations to evaluate the impact of different window air-conditioner locations on the thermal comfort in an office rooms (OR). This paper compares the air distribution for an office room by using computational fluid dynamics (CFD) modeling. The air distribution was modeled for a typical office room window air conditioning unit, air supply from a high pressure on the top and the low pressure exhaust on the bottom considering the existing manufacturing ratios for surface areas. Calculations were done for steady-state conditions including an occupant and a light source. The discharge angle for the supply grill of the AC unit was varied from 20 to 40 degrees. The position of the air conditioner was also varied and studied at 60%, 75% and 90% of the total height of the room. In addition the location of the occupant within the office room was varied. Predictions of the air movement, room temperature, room relative humidity, comfort level, and distribution of contaminants within the office room are shown. Analysis of these simulations is discussed. The positions of the air-conditioner unit, the inlet angle and the occupant position in the office room have shown to have important impacts on air quality and thermal comfort. Results are in good agreement with available experimental data.

scholarly journals The Impact of Infiltration on Heating Systems Dimensioning in Estonian Climate

2020 ◽  
Vol 172 ◽  
pp. 05004
Author(s):  
Raimo Simson ◽  
Taaniel Rebane ◽  
Martin Kiil ◽  
Martin Thalfeldt ◽  
Jarek Kurnitski
Keyword(s):  
Air Temperature ◽  
Indoor Air ◽  
Energy Performance ◽  
Simulation Software ◽  
Heat Losses ◽  
Climatic Data ◽  
Heating Systems ◽  
Air Temperatures ◽  
The Impact ◽  
Calculation Models

In this study we analysed the climatic conditions for infiltration estimation, different calculation methods and infiltration impact on heat load for heating systems dimensioning. To determine the wind conditions at low air temperatures of the coastal- and inland climatic zones in Estonia, 42 years of climatic data for Tallinn and Tartu were investigated. Calculation models with detailed air leakages were constructed of a single and two-storey detached house using dynamic simulation software IDA ICE. Simulations were carried out with the constructed calculation models, simulating various wind and sheltering conditions to determine the heating load of the buildings under measured wind conditions at the design external air temperatures. The simulation results were compared with results calculated with European Standard EN 12831:2017, methodology given in the Estonian regulation for calculating energy performance of buildings and with simulations using the default settings in IDA ICE based on the ASHRAE design day conditions. The percentage of heat losses caused by infiltration was found as 13-16% of all heat losses for the studied buildings. Simulations with historical climate periods showed that even in windy weather conditions the heating system dimensioned by the methods analysed may not be able to provide the required indoor air temperature. Analysis using the coldest and windiest periods showed that when systems are dimensioned by the studied methods, the highest decline in indoor air temperature occurs on the windiest day and not on the coldest day. The impact of high wind speeds and low sheltering conditions resulted up to 50% of all heat losses.

Applying the Passivhaus standard to a terraced house in a hot and humid tropical climate – Evaluation of comfort and energy performance

2020 ◽  
Vol 41 (3) ◽  
pp. 247-260
Author(s):  
Roy Candra Sigalingging ◽  
David Chow ◽  
Steve Sharples
Keyword(s):  
Relative Humidity ◽  
Thermal Comfort ◽  
Air Conditioning ◽  
Best Practice ◽  
Natural Ventilation ◽  
Tropical Climate ◽  
Energy Performance ◽  
Tropical Region ◽  
Humid Tropical Climate ◽  
Air Temperatures

In a hot and humid tropical climate, natural ventilation brings high levels of moisture into dwellings that, together with occupant activity, can result in very elevated internal relative humidity levels. Coupling these high relative humidities with high internal air temperatures creates occupant thermal discomfort, which is typically ameliorated in the tropics using energy-intensive air conditioning systems. This paper has investigated the potential benefits for thermal comfort and energy usage of applying the German Passivhaus standard to tropical dwellings. By creating a super insulated and air-tight envelope, the Passivhaus standard reduces fabric heat transfer, controls air infiltration and provides low-energy comfort. Applying this approach to a tropical terraced house might be effective but could, potentially, have an adverse impact on mechanical cooling demand. This study took an actual terraced property in Jakarta, Indonesia and thermally modelled its performance as insulation and airtightness levels were incrementally improved up to the Passivhaus standard. Field measurements in the dwelling of air temperature and relative humidity were used to validate the thermal model of the existing house. The validated model then tested the feasibility of meeting the Passivhaus energy standard for cooling in the modified tropical house. Simulation allowed the effects of air conditioning (AC) and dehumidifiers on thermal comfort and cooling loads to be investigated. The research develop the Passivhaus building model that had the floor insulation removed to let the ground floor act as a thermal sink and potentially provide radiant cooling. Analysis revealed that the building’s predicted air temperatures were affected in a beneficial way by having the Passivhaus without floor insulation. Practical application: Cooling in hot and humid tropical region is an energy-intensive approach. Design approaches that can bring comfort and save energy for the occupant are essential. The success of Passivhaus standard in mild climate might be transferable to bring comfort in tropical housing. Best practice can be developed by analysing the Passivhaus building performance in hot and humid tropical region.

Numerical analysis of local thermal comfort in a plan office under natural ventilation

2019 ◽  
Vol 29 (7) ◽  
pp. 972-986 ◽  
Author(s):  
Xiang Deng ◽  
Zijing Tan
Keyword(s):  
Thermal Comfort ◽  
Natural Ventilation ◽  
Meteorological Data ◽  
Ventilation System ◽  
Comfort Level ◽  
Open Plan ◽  
Computational Fluid Dynamics Cfd ◽  
Internal Volume ◽  
Local Thermal Comfort ◽  
Primary Focus

The utilisation of automatic controlled natural wind in office buildings to maintain indoor thermal comfort has gained wide attention in recent years. Generally, it is not necessary to ensure that the whole internal volume of a building with large open spaces meets thermal comfort requirements. Primary focus should be on occupied areas. Accordingly, the local thermal comfort in an open-plan office with automatic controlled natural ventilation system was investigated numerically and experimentally. A computational fluid dynamics (CFD)-based method was presented for indoor environment and thermal comfort prediction. Long-term in situ measurement was conducted during summer and transition seasons. The meteorological data were collected by a mini weather station located on the roof of the target building. Meanwhile, indoor air velocity, temperature, turbulence intensity and wall temperatures were recorded locally. Three thermal comfort indices, i.e. thermal stratification represented by percentage dissatisfied (PD), the extended predicted mean vote (PMVe) and draught rate were employed to evaluate the thermal comfort level of the interested areas during natural ventilation period. The numerical results revealed a risk of local thermal dissatisfaction under low outdoor temperature and strong windy conditions.

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