scholarly journals Review on the HVAC System Modeling Types and the Shortcomings of Their Application

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Raad Z. Homod
Keyword(s):  
Large Scale ◽  
Energy Savings ◽  
Thermal Sensation ◽  
System Modeling ◽  
Thermal Inertia ◽  
Hvac System ◽  
Advantages And Disadvantages ◽  
Building Models ◽  
Hvac System Modeling ◽  
High Thermal Inertia

The modeling of the heating, ventilation, and air conditioning (HVAC) system is a prominent topic because of its relationship with energy savings and environmental, economical, and technological issues. The modeling of the HVAC system is concerned with the indoor thermal sensation, which is related to the modeling of building, air handling unit (AHU) equipments, and indoor thermal processes. Until now, many HVAC system modeling approaches are made available, and the techniques have become quite mature. But there are some shortcomings in application and integration methods for the different types of the HVAC model. The application and integration processes will act to accumulate the defective characteristics for both AHU equipments and building models such as nonlinear, pure lag time, high thermal inertia, uncertain disturbance factors, large-scale systems, and constraints. This paper shows types of the HVAC model and the advantages and disadvantages for each application of them, and it finds out that the gray-box type is the best one to represent the indoor thermal comfort. But its application fails at the integration method where its response deviated to unreal behavior.

scholarly journals A Review on Industrial Cooling System

2020 ◽  
Vol 6 (7) ◽  
pp. 1-4
Author(s):  
Shubham Shukla ◽  
Rajeev Arya ◽  
Nilesh Diwakar
Keyword(s):  
Air Conditioning ◽  
Energy Savings ◽  
Cooling System ◽  
Thermal Sensation ◽  
System Modeling ◽  
Thermal Processes ◽  
Hvac System ◽  
Air Conditioning System ◽  
Air Handling Unit ◽  
Hvac System Modeling

The modeling of the heating, ventilation, and air conditioning (HVAC) system is a prominent topic because of its relationship with energy savings and environmental, economic, and technological issues. The modeling of the HVAC system is concerned with the indoor thermal sensation, which is related to the modeling of building, air handling unit (AHU) equipment’s, and indoor thermal processes.  This paper shows the HVAC model and the Winter Air Conditioning System, Summer Air Conditioning System. Until now, many HVAC system modeling approaches are made available, and the techniques have become quite mature.

scholarly journals On the Energy Performance of an Innovative Green Roof in the Mediterranean Climate

Energies ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 5163
Author(s):  
Luca Evangelisti ◽  
Claudia Guattari ◽  
Gianluca Grazieschi ◽  
Marta Roncone ◽  
Francesco Asdrubali
Keyword(s):  
Urban Areas ◽  
Energy Savings ◽  
Thermal Inertia ◽  
Thermal Conditions ◽  
Noise Pollution ◽  
Green Roofs ◽  
Energy Performance ◽  
Thermal Insulating ◽  
Heating And Cooling ◽  
High Thermal Inertia

Green roofs have a thermal insulating effect known since ancient times. In the building sector, green roofs represent a sustainable passive solution to obtain energy savings, both during winter and summer. Moreover, they are a natural barrier against noise pollution, reducing sound reflections, and they contribute to clean air and biodiversity in urban areas. In this research, a roof-lawn system was studied through a long experimental campaign. Heat-flow meters, air and surface temperature sensors were used in two buildings characterized by different surrounding conditions, geometries and orientations. In both case studies, the thermal behaviors of the roof-lawn system were compared with the conventional roofs. In addition, a dynamic simulation model was created in order to quantify the effect of this green system on the heating and cooling energy demands. The roof-lawn showed a high thermal inertia, with no overheating during summer, and a high insulating capacity, involving energy savings during winter, and consequently better indoor thermal conditions.

scholarly journals Experimental Evaluation and Numerical Simulation of the Thermal Performance of a Green Roof

2020 ◽  
Vol 10 (5) ◽  
pp. 1767 ◽  
Author(s):  
Claudia Guattari ◽  
Luca Evangelisti ◽  
Francesco Asdrubali ◽  
Roberto De Lieto Vollaro
Keyword(s):  
Energy Savings ◽  
Thermal Inertia ◽  
Green Roofs ◽  
Energy Performance ◽  
High Energy ◽  
Active Systems ◽  
Building Models ◽  
Collateral Effect ◽  
Building Components ◽  
Energy Simulations

In the building sector, both passive and active systems are essential for achieving a high-energy performance. Considering passive solutions, green roofs represent a sustainable answer, allowing buildings to reach energy savings, and also reducing the collateral effect of the Urban Heat Island (UHI) phenomenon. In this study, a roof-lawn system was investigated by means of an extended measurement campaign, monitoring the heat transfer across the roof. Heat-flow meters and air- and surface-temperature probes were applied in a real building, in order to compare the performance of the roof-lawn system with a conventional roof. This experimental approach was followed to quantify the different thermal behaviors of the building components. Moreover, an equivalent thermal model of the roof-lawn system was studied, in order to obtain the equivalent thermal properties of the roof, useful for setting building models for yearly energy simulations. The roof-lawn system revealed its advantages, showing a higher thermal inertia with no overheating in summertime and a lower thermal transmittance with energy savings in wintertime, and, consequently, better indoor conditions for the occupants of the building.

Comparison of HVAC system modeling in EnergyPlus, DeST and DOE-2.1E

2013 ◽  
Vol 7 (1) ◽  
pp. 21-33 ◽  
Author(s):  
Xin Zhou ◽  
Tianzhen Hong ◽  
Da Yan
Keyword(s):  
System Modeling ◽  
Hvac System ◽  
Hvac System Modeling

Implantable neural interfaces

2018 ◽  
Author(s):  
Stefano Vassanelli
Keyword(s):  
Brain Function ◽  
Large Scale ◽  
Ionic Channels ◽  
Patch Clamp Technique ◽  
Advantages And Disadvantages ◽  
Optogenetic Stimulation ◽  
Physical Interfaces ◽  
The Brain

Establishing direct communication with the brain through physical interfaces is a fundamental strategy to investigate brain function. Starting with the patch-clamp technique in the seventies, neuroscience has moved from detailed characterization of ionic channels to the analysis of single neurons and, more recently, microcircuits in brain neuronal networks. Development of new biohybrid probes with electrodes for recording and stimulating neurons in the living animal is a natural consequence of this trend. The recent introduction of optogenetic stimulation and advanced high-resolution large-scale electrical recording approaches demonstrates this need. Brain implants for real-time neurophysiology are also opening new avenues for neuroprosthetics to restore brain function after injury or in neurological disorders. This chapter provides an overview on existing and emergent neurophysiology technologies with particular focus on those intended to interface neuronal microcircuits in vivo. Chemical, electrical, and optogenetic-based interfaces are presented, with an analysis of advantages and disadvantages of the different technical approaches.

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