scholarly journals A NARX model to Predict Cabin Air Temperature to Ameliorate HVAC Functionality

2021 ◽  
Author(s):  
Srikanth Kolachalama ◽  
Hafiz Malik
Keyword(s):  
Air Temperature ◽  
Air Conditioning ◽  
Signal To Noise Ratio ◽  
Fluid Pressure ◽  
Test Vehicle ◽  
Air Conditioning System ◽  
Multiple Datasets ◽  
Iterative Analysis ◽  
Optimal Set ◽  
Vehicular Technology

The vehicular technology has integrated many features in the system, which enhances the safety and comfort of the user. Among these features, heating, ventilation, and air conditioning (HVAC) is the only feature that maintains the set cabin air temperature (CAT). The user’s command drives the set CAT, and the thermostat provides feedback to the HVAC to maintain the set CAT. The CAT is increased by extracting the heat from the engine surface produced by the fuel combustion, whereas the CAT is reduced by the known processes of the air conditioning system (ACS). Therefore, the CAT driven by the user’s command may not be optimal, and estimating the optimal CAT is still unsolved. In this work, the user was allowed to input a range for CAT instead of a single value. Optimal HVAC criteria were defined, and the CAT was estimated by performing iterative analysis in the user-selected range satisfying the criteria. The HVAC criteria were defined based on two measurable parameters: air conditioning refrigerant fluid pressure (ACRFP) and engine surface temperature (EST) empirically defined as the vector CATOP. In this article, a NARX DL model by mapping the vehicle-level vectors (VLV) to predict the CATOP in real-time using field data obtained from a 2020 Cadillac CT5 test vehicle. Utilising the DL model, CATOP for future time steps were predicted by varying the CAT in the definite range and applying HVAC criteria. Thus, an optimal set CAT was estimated, corresponding to the optimal CATOP defined by the HVAC criteria. We performed the validation of the DL model for multiple datasets using traditional statistical techniques, namely, signal-to-noise ratio (SNR) values, first-order derivatives (FOD), and root-mean-square error (RMSE).

scholarly journals A NARX Model to Predict Cabin Air Temperature to Ameliorate HVAC Functionality

Vehicles ◽  
2021 ◽  
Vol 3 (4) ◽  
pp. 872-889
Author(s):  
Srikanth Kolachalama ◽  
Hafiz Malik
Keyword(s):  
Air Temperature ◽  
Air Conditioning ◽  
Signal To Noise Ratio ◽  
Fluid Pressure ◽  
Air Conditioning System ◽  
Multiple Datasets ◽  
New Process ◽  
Iterative Analysis ◽  
Optimal Set ◽  
Vehicular Technology

Vehicular technology has integrated many features in the system, which enhances the safety and comfort of the user. Among these features, heating, ventilation, and air conditioning (HVAC) is the only feature that maintains the set cabin air temperature (CAT). The user’s command drives the set CAT, and the thermostat provides feedback to the HVAC to maintain the set CAT. The CAT is increased by extracting the heat from the engine surface produced by the fuel combustion, whereas the CAT is reduced by the known processes of the air conditioning system (ACS). Therefore, the CAT driven by the user’s command may not be optimal, and estimating the optimal CAT is still unsolved. In this work, we propose a new process where the user can input a range for CAT instead of a single value. Optimal HVAC criteria were defined, and the CAT was estimated by performing iterative analysis in the user-selected range satisfying the criteria. The HVAC criteria were defined based on two measurable parameters: air conditioning refrigerant fluid pressure (ACRFP) and engine surface temperature (EST) empirically defined as the vector CATOP. In this article, a NARX DL model was used by mapping the vehicle-level vectors (VLV) to predict the CATOP in real-time using field data obtained from a 2020 Cadillac CT5 test vehicle. Utilising the DL model, CATOP for future time steps was predicted by varying the CAT in the definite range and applying HVAC criteria. Thus, an optimal set CAT was estimated, corresponding to the optimal CATOP defined by the HVAC criteria. We performed the validation of the DL model for multiple datasets using traditional statistical techniques, namely, signal-to-noise ratio (SNR) values, first-order derivatives (FOD), and root-mean-square error (RMSE).

Overall Optimization and Exergy Analysis of an Air Conditioning System Using a Series-Series Counterflow Arrangement of Water Chillers

2019 ◽  
Vol 27 (04) ◽  
pp. 1950034 ◽  
Author(s):  
Nguyen Minh Phu
Keyword(s):  
Air Conditioning ◽  
Exergy Analysis ◽  
Cooling Tower ◽  
Exergy Efficiency ◽  
Air Conditioning System ◽  
In Series ◽  
Main Components ◽  
Compressor Power ◽  
Cooling Coil ◽  
Optimal Set

When water chillers are arranged in series-series counterflow (SSCF), the compressor lift of each chiller is decreased in comparison with that of water chillers in parallel. This means that the compressor power of SSCF chillers is lower than that of parallel chillers. In this paper, models of the main components in an air conditioning system were developed and verified to predict the behaviors of the whole system with respect to SSCF chillers. The results showed that performance was maximized with three SSCF chillers when the system was operated with normal set points. The performance was further improved to 26% and decreased with the number of SSCF chillers when the system was operated with optimal set points. The SSCF chiller system also demonstrated higher exergy efficiency regardless of the number of SSCF chillers. The irreversibility of components in SSCF chillers was rather low. However, the irreversibility of the cooling tower and cooling coil was slightly higher and lower, respectively, than those in the parallel chiller system.

Theoretical analysis of heat and mass transfer processes in an evaporative cooling system with zeolite desiccant powered by solar energy

2018 ◽  
Author(s):  
◽  
Amged Al Ezzi
Keyword(s):  
Water Vapor ◽  
Flat Plate ◽  
Air Temperature ◽  
Air Conditioning ◽  
Cooling System ◽  
Evaporative Cooling ◽  
Air Conditioning System ◽  
Coating Method ◽  
Evaporative Cooler ◽  
Desiccant Material

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Concerns about energy sources depletion and environmental pollution issues have been raised and is a top priority of the global community. Refrigeration machines have been received the major of attention because of their energy consumption and pollution. Different from traditional cooling strategies, desiccant cooling technology (DCT) has been emergent as a promising alternative giving the fact that the economic-ecological air conditioning system is not restricted to hot and dry climates only. In the current experimental study, an advancement solar assisted desiccant cooling system (SADCS) is presented. The advantage is to use only a fraction of the energy of typical compressor-based cooling systems. The advancements have taken place into the dehumidification, evaporator, and regeneration sections. The role of appropriate choosing of the desiccant material type on the adsorption process has been presented, and a Faujasite (FAU) 13X zeolite is utilized in the dehumidification stage. A novel monolayer coating method has conducted. The new coating method has insured no external water vapor condensation ruins the desiccant material during relative humidity working range (20-97) %. Moreover, the new coating method allows to increase the performance of the adsorption and desorption processes, respectively. By giving the coming air stream the ability to pass through and surround the zeolite beads, accessibility to adsorb and desorb water vapor molecules is easier as more rooms are available. That clearly has been stated as 6450 g of zeolite holds 684 g of water in full saturation status within 37 minutes and regenerates by less than 120 [degree]C air temperature within 66 minutes. In the evaporative cooling section, an effective small compact evaporative cooler (CEC) system dealing only with product flow is introduced. The new CEC is utilized direct and indirect evaporation of water mechanisms combined in cross channels to cool air. Dropping air temperature by (5-7) [degree]C has recorded without desiccant stage. Supplying the required regeneration energy from a green energy source was essential in this study. For this purpose, an innovative flat plate double-mesh air solar collector has designed and carried out. In the new collector, a double copper mesh frames were fixing within a double Plexiglas covers flat plate collector. Experimental results show a good consistent with the mathematical model. With an average 0.71 solar fraction and 80 [degree]C exit air temperature, the collector presents 0.73 as thermal efficiency. As the improvements of the desiccant air-conditioning system turns out globally recognized by the progress in different research outcomes, designs, setting up and evaluation methods, it is expected that the system will be one of the most important alternative systems for the maintenance of human's environment comfort and air quality when considering the reduced dependence on conventional energy usage. Present work and results provide a reference data sets related to real adsorption dehumidification process and show that the advancement SADCS has a great potential in the future of the evaporative cooler systems.

scholarly journals Climate Compensation and Indoor Temperature Optimal Measuring Point Energy Saving Control in VAV Air-Conditioning System

Energies ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 4398 ◽  
Author(s):  
Xiuying Yan ◽  
Cong Liu ◽  
Meili Li ◽  
Ating Hou ◽  
Kaixing Fan ◽  
...  
Keyword(s):  
Energy Saving ◽  
Air Temperature ◽  
Control Strategy ◽  
Air Conditioning ◽  
Compensation Scheme ◽  
Indoor Temperature ◽  
Air Conditioning System ◽  
Measuring Point ◽  
Temperature Measuring ◽  
Environment Control

Temperature measuring point is the key to room environment control. Temperature measuring points and climate changes are directly related to the room control effect. It is of great theoretical and practical significance to study the temperature measuring points and control strategy based on climate compensation. In this study, first, the climate compensation concept in a heating system was introduced into a variable air volume (VAV) air-conditioning system. The heating load was modeled as a function of supply air temperature by analyzing the heat exchange. Based on each control link of subsystems, a climate compensation scheme is proposed to determine the optimal set-point of the supply air temperature. At the same time, a layout of multiple temperature measuring points of an air-conditioned room was studied. Furthermore, the optimal indoor temperature measuring point was determined using an adaptive weighted fusion method. Finally, simulation results show that the proposed method has better control effects on indoor temperature adjustment compared with the traditional method. The optimal supply air temperature in summer and winter was determined according to the proposed climate compensation scheme, and the supply air temperature was controlled using an improved single-neuron adaptive control strategy. Experimental results show that the maximum energy saving can reach up to 35.5% in winter and 6.1% in summer.

Numerical simulation and mock-up experimental measurement of the air conditioning system for the 3 GeV Taiwan Photon Source electron storage ring

2010 ◽  
Vol 1 (MEDSI-6) ◽  
Author(s):  
J. C. Chang ◽  
Z. D. Tsai ◽  
C. Y. Liu ◽  
Y. C. Chung ◽  
J. R. Chen
Keyword(s):  
Numerical Simulation ◽  
Flow Pattern ◽  
Air Temperature ◽  
Storage Ring ◽  
Air Conditioning ◽  
Air Conditioning System ◽  
Utility System ◽  
The One ◽  
Radiation Research ◽  
Photon Source

National Synchrotron Radiation Research Center, Taiwan, is currently constructing the civil buildings and utility system of the Taiwan Photon Source. The air conditioning (AC) system of the storage ring tunnel was designed based on those of existing Taiwan Light Source and some international advanced accelerators. To predict the air temperature variation and flow pattern in tunnel more precisely, we applied 3D computational fluid dynamics scheme and built up a one-cell mock-up equipped with AC system. In the 3D numerical model, effects of magnets of the booster and the storage ring, girders, cable trays, front ends and the supplied air wind duct are all taken into account. The temperature variations and flow pattern were shown through the numerical simulation. Measured air temperature data in the one-cell mock-up were also collected.

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