scholarly journals Evaluation of thermal comfort conditions in a classroom equipped with radiant cooling systems and subjected to uniform convective environment

2011 ◽  
Vol 35 (3) ◽  
pp. 1292-1305 ◽  
Author(s):  
Eusébio Z.E. Conceição ◽  
Ma Manuela J.R. Lúcio
Keyword(s):  
Thermal Comfort ◽  
Cooling Systems ◽  
Radiant Cooling

scholarly journals EVALUATION OF THE RADIANT COOLING CEILING PANELS WITH A REVERSIBLE HEAT PUMP

2021 ◽  
Vol 2021 (6) ◽  
pp. 5317-5321
Author(s):  
MIROSLAV RIMAR ◽  
◽  
MARCEL FEDAK ◽  
ANDRII KULIKOV ◽  
OLHA KULIKOVA ◽  
...  
Keyword(s):  
Thermal Comfort ◽  
Present Article ◽  
Heat Pump ◽  
Time Management ◽  
Thermal Conditions ◽  
Climatic Conditions ◽  
Cooling Systems ◽  
Suitable Alternative ◽  
Radiant Cooling ◽  
Conventional Cooling

Thermal comfort is one of the basic prerequisites for appropriate operating of the building. Ensuring thermal comfort in the summer means creating suitable thermal conditions in the interior. The present article evaluates the operation of radiant ceiling cooling, which is a suitable alternative for conventional cooling systems. Experimental cooling systems using a reversible heat pump as a source of chilled water were analyzed. The presented results indicate the ability of the system to ensure the required interior temperature under suitable climatic conditions using appropriate time management and sufficient accumulation. The required temperature is 24.51 °C and the deviation does not exceed ± 0.5K.

An Assessment of Thermal Comfort for Thermoelectric-Based Radiant Cooling Systems: A Numerical Investigation

2021 ◽  
Author(s):  
Mohadeseh Seyednezhad ◽  
Hamidreza Najafi
Keyword(s):  
Thermal Comfort ◽  
Test Chamber ◽  
Comfort Level ◽  
Dew Point ◽  
Mean Radiant Temperature ◽  
Spherical Object ◽  
Cooling Systems ◽  
Modeling And Analysis ◽  
Radiant Cooling ◽  
Radiant Temperature

Abstract Studying various innovative cooling/heating technologies as alternatives to vapor-compression refrigeration cycles has received growing attention over the last few years. Thermoelectric (TE) systems are among the promising emerging technologies in this category. In the present paper, numerical modeling and analysis is performed using COMSOL Multiphysics to assess the performance of a thermoelectric (TE)-based radiant cooling ceiling panel on the thermal comfort in a test chamber. The system consists of a rectangular test chamber (∼ 1.2 m × 1.2 m × 1.5 m) with a ceiling panel fabricated on the center of the ceiling (0.6 m × 0.6 m × 0.002 m). Four TE modules are installed on the backside of the ceiling panel producing a cooling effect to maintain the ceiling temperature at the desired level. The lowered temperature of the ceiling panel allows heat exchange through radiation and convection. A spherical object is used to model a globe thermometer (GT) and capture the mean radiant temperature inside of the chamber. The variation of mean radiant temperature and operative temperature versus time are assessed under natural convection, and the comfort level is evaluated using the PMV method based on ASHRAE Standard 55. Design challenges, such as temperature limitation to the dew point temperature, among others, will be discussed. The result of this study provides insights regarding the expected thermal comfort from TE-based radiant cooling systems under various conditions.

Thermal environment and thermal comfort built by decoupled radiant cooling units with low radiant cooling temperature

2021 ◽  
Vol 206 ◽  
pp. 108342
Author(s):  
Yuying Liang ◽  
Nan Zhang ◽  
Huijun Wu ◽  
Xinhua Xu ◽  
Ke Du ◽  
...  
Keyword(s):  
Thermal Comfort ◽  
Thermal Environment ◽  
Cooling Temperature ◽  
Radiant Cooling

Design Range of Indoor Relative Humidity in Radiant Cooling Environment

2011 ◽  
Vol 243-249 ◽  
pp. 4905-4908
Author(s):  
Xue Min Sui ◽  
Xu Zhang ◽  
Guang Hui Han
Keyword(s):  
Relative Humidity ◽  
Thermal Comfort ◽  
Mean Radiant Temperature ◽  
Design Standards ◽  
Human Thermal Comfort ◽  
Radiant Cooling ◽  
Climate Parameter ◽  
Radiant Temperature ◽  
Thermal Comfort Model ◽  
The Impact

Relative humidity is an important micro-climate parameter in radiant cooling environment. Based on the human thermal comfort model, this paper studied the effect on PMV index of relative humidity, and studied the relationship of low mean radiant temperature and relative humidity, drew the appropriate design range of indoor relative humidity for radiant cooling systems.The results show that high relative humidity can compensate for the impact on thermal comfort of low mean radiant temperature, on the premise of achieving the same thermal comfort requirements. However, because of the limited compensation range of relative humidity, together with the constraints for it due to anti-condensation of radiant terminal devices, the design range of relative humidity should not be improved, and it can still use the traditional air-conditioning design standards.

scholarly journals Thermal Comfort and Energy Analysis of a Hybrid Cooling System by Coupling Natural Ventilation with Radiant and Indirect Evaporative Cooling

Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7825
Author(s):  
Pradeep Shakya ◽  
Gimson Ng ◽  
Xiaoli Zhou ◽  
Yew Wah Wong ◽  
Swapnil Dubey ◽  
...  
Keyword(s):  
Thermal Comfort ◽  
Hybrid System ◽  
Natural Ventilation ◽  
Cooling System ◽  
Evaporative Cooling ◽  
Supply System ◽  
Hybrid Cooling ◽  
Air Supply ◽  
Radiant Cooling ◽  
Indirect Evaporative Cooling

A hybrid cooling system which combines natural ventilation with a radiant cooling system for a hot and humid climate was studied. Indirect evaporative cooling was used to produce chilled water at temperatures slightly higher than the dew point. With this hybrid system, the condensation issue on the panel surface of a chilled ceiling was overcome. A computational fluid dynamics (CFD) model was employed to determine the cooling load and the parameters required for thermal comfort analysis for this hybrid system in an office-sized, well-insulated test room. Upon closer investigation, it was found that the thermal comfort by the hybrid system was acceptable only in limited outdoor conditions. Therefore, the hybrid system with a secondary fresh air supply system was suggested. Furthermore, the energy consumptions of conventional all-air, radiant cooling, and hybrid systems including the secondary air supply system were compared under similar thermal comfort conditions. The predicted results indicated that the hybrid system saves up to 77% and 61% of primary energy when compared with all-air and radiant cooling systems, respectively, while maintaining similar thermal comfort.

scholarly journals Analysis of the Methodologic Assumptions of the NOM-020-ENER-2011—Mexican Residential Building Standard

Environments ◽  
2018 ◽  
Vol 5 (11) ◽  
pp. 118 ◽  
Author(s):  
Ignacio Martin-Dominguez ◽  
Norma Rodriguez-Muñoz ◽  
Claudia Romero-Perez ◽  
Mario Najera-Trejo ◽  
Naghelli Ortega-Avila
Keyword(s):  
Thermal Comfort ◽  
Low Income ◽  
Energy Use ◽  
Housing Stock ◽  
Residential Buildings ◽  
Residential Building ◽  
Cooling Systems ◽  
Increasing Demand ◽  
The Many ◽  
Air Conditioning Systems

In Mexico, residents of low income housing mainly achieve thermal comfort through mechanical ventilation and electrical air conditioning systems. Though government and private efforts have risen to meet an increasing demand for social housing, the average construction quality and thermal comfort of new housing stock has decreased over the years. Various programs and regulations have been implemented to address these concerns, including the 2011 residential building standard NOM-020-ENER-2011. This standard attempts to limit heat gains in residential buildings, in order to reduce the energy consumption required from cooling systems, and was intended to be applied throughout Mexico. NOM-020-ENER-2011, however, divides the country into just four climatic zones and only considers the energy use of cooling systems, disregarding heating costs. The recommendations of this policy are thus inadequate for the many regions in Mexico that have mild to moderate winters. This study discusses the assumptions and calculations that underlie NOM-020-ENER-2011, identifying several problems and recommending specific changes to the standard that would lead to greater comfort and lower energy use throughout Mexico.

scholarly journals Analysis of the Effect of Using External Venetian Blinds on the Thermal Comfort of Users of Highly Glazed Office Rooms in a Transition Season of Temperate Climate—Case Study

Energies ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 81 ◽  
Author(s):  
Małgorzata Fedorczak-Cisak ◽  
Katarzyna Nowak ◽  
Marcin Furtak
Keyword(s):  
Energy Consumption ◽  
Thermal Comfort ◽  
Ambient Air ◽  
Temperate Climate ◽  
Cooling Systems ◽  
Clothing Insulation ◽  
Transition Season ◽  
Venetian Blinds ◽  
Research Task ◽  
Office Rooms

Improving the energy efficiency of buildings is among the most urgent social development tasks due to the scale of energy consumption in this industry. At the same time, it is essential to meet high requirements for indoor environmental quality and thermal comfort. The issue of overheating is most often analysed in summer but it also occurs in transition seasons, when the cooling systems do not operate. The paper attempts to evaluate the effectiveness of external mobile shading elements on the microclimate of rooms with large glazed areas in the transition season. Passive solutions, such as shading elements, which limit the increase of indoor temperature, do not always allow the acquisition and maintenance of comfortable solutions for the duration of the season, as demonstrated by the authors. Temporary cooling of the rooms may be necessary to maintain comfortable conditions for the users, or other solutions should be devised to improve comfort (e.g., reduction of clothing insulation characteristics). The novelty of the study consists in the analysis of comfort in a “nearly zero energy consumption” building (NZEB) during a period not analyzed by other scientists. This is a transition period during which heating/cooling systems do not operate. The research task set by the authors involved the assessment of the possibility to reduce office space overheating in the transition season (spring) by using external shading equipment in rooms with large glazed areas. An additional research task aimed at checking the extent to which user behaviour, such as reduction in clothing insulation characteristics, can improve comfort in overheated rooms. The results of the tests reveal that the difference in the ambient air temperature between a room with external venetian blinds and an identical room with no venetian blinds in the transition season, i.e., from 27 March to 6 April 2017, ranged from 12.3 to 2.1 °C. The use of a shading system (external venetian blinds positioned at an angle of 45°) reduced the number of discomfort hours by 92% (during working hours) compared to the room without external venetian blinds. A reduction in the thermal insulation of the clothes worn by people working in the room with no venetian blinds helped to reduce the number of discomfort hours by 31%.

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