scholarly journals The Impacts of a Building’s Thermal Mass on the Cooling Load of a Radiant System under Various Typical Climates

Energies ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1356 ◽  
Author(s):  
Rong Hu ◽  
Gang Liu ◽  
Jianlei Niu
Keyword(s):  
Weather Conditions ◽  
Thermal Mass ◽  
Cooling Load ◽  
Radiation Heat ◽  
Combined System ◽  
Indoor Temperature ◽  
External Wall ◽  
Cooling Surface ◽  
Concrete Layer ◽  
Energy Plus

Cooling load is difficult to predict for a radiant system, because the interaction between a building’s thermal mass and radiation heat gain has not been well defined in a zone with a cooling surface. This study aims to reveal the effect of thermal mass in an external wall on the transmission load in a space with an active cooling surface. We investigated the thermal performances in a typical office building under various weather conditions by dynamic simulation with Energy-Plus. It was found that the thermal mass in the inside concrete layer had positives in terms of indoor temperature performance and energy conservation. The peak cooling load of the hydronic system decreases 28% in the proper operating state, taking into account the effect of the thermal mass in an external wall. Compared to the performances in zones with equivalent convective air systems (CASs), the peak cooling load and the accumulated load of the combined system (radiant system coupled by fresh air system) are higher by 9%–11% and 3%–4%, respectively. The effect of thermal mass is evident in a transient season with mild weather, when the relative effects are about 45% and 60%, respectively, for a building with radiant systems and a building with equivalent CASs.

Adjustment of indoor temperature using internal thermal mass under different tropical weather conditions

2019 ◽  
Vol 26 (2) ◽  
pp. 115-127
Author(s):  
Surjamanto Wonorahardjo ◽  
Inge Sutjahja ◽  
Siti Aisyah Damiati ◽  
Daniel Kurnia
Keyword(s):  
Weather Conditions ◽  
Thermal Mass ◽  
Indoor Temperature ◽  
Tropical Weather

scholarly journals Online Implementation of a Soft Actor-Critic Agent to Enhance Indoor Temperature Control and Energy Efficiency in Buildings

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 997
Author(s):  
Davide Coraci ◽  
Silvio Brandi ◽  
Marco Savino Piscitelli ◽  
Alfonso Capozzoli
Keyword(s):  
Energy Consumption ◽  
Temperature Control ◽  
Weather Conditions ◽  
Heating System ◽  
Building Envelope ◽  
Indoor Temperature ◽  
Model Free ◽  
Occupancy Patterns ◽  
Online Implementation ◽  
Indoor Temperature Control

Recently, a growing interest has been observed in HVAC control systems based on Artificial Intelligence, to improve comfort conditions while avoiding unnecessary energy consumption. In this work, a model-free algorithm belonging to the Deep Reinforcement Learning (DRL) class, Soft Actor-Critic, was implemented to control the supply water temperature to radiant terminal units of a heating system serving an office building. The controller was trained online, and a preliminary sensitivity analysis on hyperparameters was performed to assess their influence on the agent performance. The DRL agent with the best performance was compared to a rule-based controller assumed as a baseline during a three-month heating season. The DRL controller outperformed the baseline after two weeks of deployment, with an overall performance improvement related to control of indoor temperature conditions. Moreover, the adaptability of the DRL agent was tested for various control scenarios, simulating changes of external weather conditions, indoor temperature setpoint, building envelope features and occupancy patterns. The agent dynamically deployed, despite a slight increase in energy consumption, led to an improvement of indoor temperature control, reducing the cumulative sum of temperature violations on average for all scenarios by 75% and 48% compared to the baseline and statically deployed agent respectively.

scholarly journals How Can Floor Covering Influence Buildings’ Demand Flexibility?

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3658
Author(s):  
Hyeunguk Ahn ◽  
Jingjing Liu ◽  
Donghun Kim ◽  
Rongxin Yin ◽  
Tianzhen Hong ◽  
...  
Keyword(s):  
Demand Response ◽  
Radiant Heat ◽  
Response Strategy ◽  
Sensitivity Analyses ◽  
Thermal Mass ◽  
Cooling Load ◽  
Floor Covering ◽  
Load Shifting ◽  
Concrete Floor ◽  
Floor Surface

Although the thermal mass of floors in buildings has been demonstrated to help shift cooling load, there is still a lack of information about how floor covering can influence the floor’s load shifting capability and buildings’ demand flexibility. To fill this gap, we estimated demand flexibility based on the daily peak cooling load reduction for different floor configurations and regions, using EnergyPlus simulations. As a demand response strategy, we used precooling and global temperature adjustment. The result demonstrated an adverse impact of floor covering on the building’s demand flexibility. Specifically, under the same demand response strategy, the daily peak cooling load reductions were up to 20–34% for a concrete floor whereas they were only 17–29% for a carpet-covered concrete floor. This is because floor covering hinders convective coupling between the concrete floor surface and the zone air and reduces radiative heat transfer between the concrete floor surface and the surrounding environment. In hot climates such as Phoenix, floor covering almost negated the concrete floor’s load shifting capability and yielded low demand flexibility as a wood floor, representing low thermal mass. Sensitivity analyses showed that floor covering’s effects can be more profound with a larger carpet-covered area, a greater temperature adjustment depth, or a higher radiant heat gain. With this effect ignored for a given building, its demand flexibility would be overestimated, which could prevent grid operators from obtaining sufficient demand flexibility to maintain a grid. Our findings also imply that for more efficient grid-interactive buildings, a traditional standard for floor design could be modified with increasing renewable penetration.

The Effects of Window Film on the Performance of Window System

2014 ◽  
Vol 525 ◽  
pp. 408-411
Author(s):  
Min Seon Jang ◽  
Gyeong Seok Choi ◽  
Jae Sik Kang ◽  
Yumin Kim
Keyword(s):  
Energy Consumption ◽  
Cooling Load ◽  
Indoor Temperature ◽  
Heating And Cooling ◽  
Window System ◽  
Window Systems ◽  
Clear Glass ◽  
Window Film ◽  
And Performance ◽  
Heating And Cooling Load

Window film is generally attached the glazing in buildings to improve the thermal performance of the window system by addressing a range of problems such as indoor temperature rise, indoor temperature imbalance, degraded heating and cooling load due to excessive influx of solar radiation. To evaluate the performance of window films, window films are attached to 3mm or 6mm clear glass. However, window films are generally used on existing window systems for reducing the annual energy consumption. Therefore it is necessary to evaluate the performance of window films depending on the performance of glazing such as clear double glazing or low-e double glazing. Thus the purpose of this study is to analyze the performance of window systems when window film is attached. As a result, in the case of applying window films for reducing the SHGC of buildings, it is necessary to select window films suitable for the configuration and performance of the glazing to be installed, considering the SHGC of the entire glazing system.

Thermal performance of silica aerogel-filled double-layer glazing in a subtropical climate

2021 ◽  
Vol 11 (6) ◽  
pp. 974-981
Author(s):  
Yajun Lv ◽  
Yiming Qin ◽  
Julian Wang ◽  
Kui Yin ◽  
Huanchun Huang ◽  
...  
Keyword(s):  
Double Layer ◽  
Silica Aerogel ◽  
Energy Efficient ◽  
Air Conditioning ◽  
Weather Conditions ◽  
Research Topic ◽  
Outdoor Environment ◽  
Subtropical Climate ◽  
Cooling Load ◽  
Space Cooling

Heat gain through glazing is a major source of the space cooling load in subtropical cooling-dominant climates. Application of energy-efficient glazing systems can significantly reduce the energy consumption of air conditioning in summer. Thus, it has become a popular research topic. In this study, a sample of silica aerogel glazing was developed and prepared. Two identical insulated boxes were then constructed; one faÇade was equipped with the aerogel glazing sample and the other was prepared with a conventional double-layer glazing. An onsite measurement of the boxes’ internal thermal properties was then conducted. The two boxes were placed within the same outdoor environment. The temperature, humidity, and enthalpy values were calculated with the boxes facing different orientations and in a variety of weather conditions. The performance of the silica aerogel glazing was then evaluated by both experimental and theoretical analysis. The results of this study will provide a basis for aerogel glass building application guidelines.

scholarly journals Indoor Temperature Validation of Low-Income Detached Dwellings under Tropical Weather Conditions

Climate ◽  
2019 ◽  
Vol 7 (8) ◽  
pp. 96 ◽  
Author(s):  
R. Alexis Barrientos-González ◽  
Ricardo E. Vega-Azamar ◽  
Julio C. Cruz-Argüello ◽  
Norma A. Oropeza-García ◽  
Maritza Chan-Juárez ◽  
...  
Keyword(s):  
Case Studies ◽  
Low Income ◽  
Residential Buildings ◽  
Electricity Consumption ◽  
Environmental Parameters ◽  
Weather Conditions ◽  
Environmental Data ◽  
Mean Bias Error ◽  
Bias Error ◽  
Indoor Temperature

Urban territorial expansion generated in the last decades has brought a series of consequences, such as the variation between urban and suburban weather conditions affecting indoor temperature and increasing electricity consumption derived from the use of cooling systems. Current approaches of simulation models in residential buildings use indoor environmental data for carrying out validations to propose hygrothermal comfort alternatives for the mitigation of the effects of the external environmental conditions on the interior spaces of dwellings. In this work, an hourly evaluation of both indoor and outdoor environmental parameters of two case studies in a tropical climate was carried out, by means of a whole-building simulation approach tool during a week representative of the warmest period of the year. The integration of the collected environmental data in the theoretical model allowed us to reduce the error range of the estimated indoor temperature with results in normalized mean bias error between 7.10% and −0.74% and in coefficient of variation of the root mean square error between 16.72% and 2.62%, in the different indoor zones of the case studies. At the same time, the energy assessment showed a difference of 33% in Case 1 and −217% in Case 2 for final electricity consumption.

scholarly journals Thermal Behavior and Measures to Prevent Condensation of a Newly Developed External Wall Panel

2019 ◽  
Vol 11 (3) ◽  
pp. 912 ◽  
Author(s):  
Goopyo Hong ◽  
Suk-Won Lee ◽  
Ji-Yeon Kang ◽  
Hyung-Geun Kim
Keyword(s):  
Surface Temperature ◽  
Thermal Performance ◽  
Simulation Analysis ◽  
Thermal Characteristics ◽  
Weather Conditions ◽  
Building Envelope ◽  
Unsteady State ◽  
Wall Panel ◽  
External Wall ◽  
Thermal Transmittance

An external wall panel (EWP) as a novel alternative to provide spatial flexibility and improve the performance of external walls was developed. The purpose of this study was to analyze the thermal performance of this EWP. A simulation analysis was carried out to scrutinize whether it was vulnerable to condensation, considering South Korea’s weather conditions, and find countermeasures to prevent this. Results indicated that the indoor surface temperature with the measures of added insulation materials and an inserted thermal-breaker was over 16.5 °C and that these methods could prevent condensation. In addition, this study assessed unsteady-state thermal characteristics, linear thermal transmittance, and the effective thermal transmittance of EWP. Effective thermal transmittance was estimated in consideration of the heat transmittance of EWP and the linear thermal transmittance of its slabs and its connection parts. The thermal characteristics of the building envelope are needed to analyze effective thermal transmittance and linear thermal transmittance-associated thermal bridges.

scholarly journals When social practices produce space and create passive cooling systems in hot arid region

2022 ◽  
Vol 27 ◽  
pp. 932-944
Author(s):  
Ibtissame Benoudjafer
Keyword(s):  
Thermal Comfort ◽  
Arid Regions ◽  
Passive Cooling ◽  
Thermal Mass ◽  
Cooling Load ◽  
Cooling Systems ◽  
Cooling Strategy ◽  
Main Factors ◽  
Dry Climates ◽  
Passive Cooling Systems

Abstract. Practice social of people is the key to produce space and give a possibility to maintain thermal comfort and energy efficiency. The main objective of this research is to adapt the traditional strategies in the architecture actual, to achieved a thermal comfort and improve on reducing cooling load through the using of vernacular gait. Today, it is necessary to practice these systems in the current or conventional architecture of household. The study is especially for arid cities namely the region of Saoura, in the hot and dry climatic zone in Algeria, considered for this study. Two main factors is considered such as design and urban where taken into account in order to select the appropriate and specific passive cooling strategy. The results show that the passive cooling strategy of courtyard would be appropriate for arid regions, however a high thermal mass would be suitable for construction. In conclusion, this work made it possible to choose a suitable passive cooling strategy for all types of construction in hot and dry climates. Finally, this paper puts forward a set of recommendations to improve the passive design of future buildings in hot and arid climates.  

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