scholarly journals 1D analysis of cool down simulation of vehicle HVAC system

2020 ◽  
pp. 99-99
Author(s):  
Gokhan Sevilgen ◽  
Halil Bayram ◽  
Muhsin Kilic
Keyword(s):  
Energy Consumption ◽  
Air Temperature ◽  
Thermal Performance ◽  
Thermal Conditions ◽  
Hvac System ◽  
Maximum Increase ◽  
Vehicle Cabin ◽  
1D Model ◽  
R 134A ◽  
Air Conditioning Systems

In this paper, a detailed combined 1D model of Heating, Ventilation and Air Conditioning systems of a vehicle were developed by using the LMS Imagine Lab Amesim software package. The numerical simulations were considered for soaking and cool down analysis under different environmental conditions. The thermal performance of different refrigerants as R-134a and R-1234yf were evaluated in terms of thermal performance and energy consumption. According to the soaking simulation results, the cabin air temperature values ranged from 49?C to 57?C in general. The maximum increase in cabin air temperature value was about 22?C obtained for 1000 15 W/m2 solar load. The total time until reaching the steady-state conditions for a target temperature value (23.5?C) was different for all simulations. The total time was calculated as 910 seconds for 1000 W/m2 solar load by using R134a refrigerant loop. The results also showed that although the thermal performance of R-134a was slightly better, R-1234yf can be used due to its environmental properties with acceptable performance. The calculated COP values during cooldown analysis were ranged from 1.71 to 4.52 in general. The minimum value was obtained for the cases which had a maximum solar load and higher cabin interior temperature values. The calculated temperature data for soaking and cool down analysis were in good agreement with the reference data presented in this study. These numerical results are very important for reducing the thermal load of the vehicle cabin considering energy consumption of the HVAC system for different thermal conditions.

scholarly journals Mitigation Strategies for Overheating and High Carbon Dioxide Concentration within Institutional Buildings: A Case Study in Toronto, Canada

Buildings ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 124 ◽  
Author(s):  
Claire Tam ◽  
Yuqing Zhao ◽  
Zaiyi Liao ◽  
Lian Zhao
Keyword(s):  
Carbon Dioxide ◽  
Air Quality ◽  
Indoor Air Quality ◽  
Air Temperature ◽  
Indoor Air ◽  
Indoor Environment ◽  
Thermal Conditions ◽  
Co2 Concentration ◽  
Hvac System

Indoor air quality and thermal conditions are important considerations when designing indoor spaces to ensure occupant health, satisfaction, and productivity. Carbon dioxide (CO2) concentration and indoor air temperature are two measurable parameters to assess air quality and thermal conditions within a space. Occupants are progressively affected by the indoor environment as the time spent indoors prolongs. Specifically, there is an interest in carrying out investigations on the indoor environment through surveying existing Heating, Ventilation, Air Conditioning (HVAC) system operations in classrooms. Indoor air temperature and CO2 concentration in multiple lecture halls in Toronto, Canada were monitored; observations consistently show high indoor air temperature (overheating) and high CO2 concentration. One classroom is chosen as a representative case study for this paper. The results verify a strong correlation between the number of occupants and the increase in air temperature and CO2 concentration. Building Energy Simulation (BES) is used to investigate the causes of discomfort in the classroom, and to identify methods for regulating the temperature and CO2 concentration. This paper proposes retro-commissioning strategies that could be implemented in institutional buildings; specifically, the increase of outdoor airflow rate and the addition of occupancy-based pre-active HVAC system control. The proposed retrofit cases reduce the measured overheating in the classrooms by 2-3 °C (indoor temperature should be below 23 °C) and maintain CO2 concentration under 900 ppm (the CO2 threshold is 1000 ppm), showing promising improvements to a classroom’s thermal condition and indoor air quality.

scholarly journals Influence of detailing the climate model on the calculation of energy consumption

2020 ◽  
Vol 164 ◽  
pp. 02008
Author(s):  
Elena Malyavina ◽  
Olga Malikova ◽  
Luong Van Pham
Keyword(s):  
Energy Consumption ◽  
Relative Humidity ◽  
Air Temperature ◽  
Climate Model ◽  
Cooling System ◽  
Climatic Data ◽  
Outdoor Air ◽  
Direct Measurements ◽  
Air Conditioning Systems ◽  
Parameter Values

The repeatability of outdoor air temperature and enthalpy combinations in a construction area is a necessary initial information for calculating the energy consumption of air conditioning systems. The most convenient form of presenting climatic data in such calculations is the probabilistic-statistical model, which constitutes a Table, the cells of which show the probabilistic repeatability of the outdoor air temperature and relative humidity. The parameter values given on the vertical and horizontal scales, that form the cell boundaries, can be taken with larger or smaller increments. The paper that served as the basis for this article, provides verification of the initial climatic model detailing experimentally under full-scale conditions in the city of Hanoi (Vietnam). The criterion for the appropriate model detailing was the deviation of the energy consumption estimates of the room cooling system, got experimentally and by calculation. Moreover, the calculations were performed not only on two climate probabilistic and statistical models, but also on the data of direct measurements of the outdoor air temperature and relative humidity with an accuracy of 0.1 for temperature and up to 2 % for relative humidity.

Challenges and Issues of IoT Application in Heating Ventilating Air Conditioning Systems

2021 ◽  
pp. 171-193
Author(s):  
Kapilan N. ◽  
Vidhya P.
Keyword(s):  
Energy Consumption ◽  
Human Interaction ◽  
Security And Privacy ◽  
Hvac System ◽  
System Components ◽  
Iot Platforms ◽  
Commercial Applications ◽  
Air Conditioning Systems ◽  
Diverse Data ◽  
The Internet Of Things

The internet of things (IoT) is a system consisting of computing, mechanical, and electronic devices, which are having ability to transfer data in network without human interaction. The sensors used in IoT collect and transfer the data to the cloud, which is further processed using software to perform an action. The IoT is one of the fastest growing industries, and in recent years, it is most widely used in HVAC systems in residential and commercial applications to reduce the energy consumption as building consumes by approximately 40% of total energy. The IoT reduces the energy consumption of the building by optimizing the process variables of HVAC system components, increases life of system components, enhances the comfort of the occupants, and provides remote control of the system. However, there are challenges in data security and privacy, and also there is a lack of IoT platforms specifically oriented towards the proper processing, management, and analysis of such large and diverse data.

LOW GLOBAL WARMING REFRIGERANTS FOR RESIDENTIAL AIR CONDITIONING APPLICATIONS

2014 ◽  
Vol 22 (02) ◽  
pp. 1440005 ◽  
Author(s):  
MARK SPATZ ◽  
SAMUEL YANA MOTTA ◽  
CHRISTOPHER SEETON ◽  
YONGMING NIU
Keyword(s):  
Global Warming ◽  
Thermal Properties ◽  
Environmental Impact ◽  
Thermal Performance ◽  
Global Warming Potential ◽  
Air Conditioning ◽  
Flammability Characteristics ◽  
R 134A ◽  
Residential Air Conditioning ◽  
Air Conditioning Systems

Due to the growing global concerns around the use of refrigerants with relatively high global warming potential, new refrigerants with the positive attributes of both high thermal performance and low environmental impact are currently in development by Honeywell. These new refrigerants exhibit promising performance when compared with refrigerants currently used in stationary AC systems such as those that use R-410A, R-407C, and R-134a, for example. These new refrigerants also show significantly lower flammability characteristics than the much more flammable hydrocarbons. Replacements of common HFC refrigerants such as R-410A and R-407C are discussed for residential air conditioning applications. Thermal properties as well as experimental results in representative air conditioning systems are presented, showing the benefits of using these new refrigerants.

APPLICATION OF HYDROCARBON BASED REFRIGERANTS FOR AIR CONDITIONING IN INDONESIA

2011 ◽  
Vol 19 (04) ◽  
pp. 303-309 ◽  
Author(s):  
ARI D. PASEK ◽  
ARYADI SUWONO
Keyword(s):  
Global Warming ◽  
Energy Consumption ◽  
Air Conditioning ◽  
Performance Test ◽  
Saturation Pressure ◽  
Electrical Energy ◽  
Electrical Energy Consumption ◽  
Refrigerant Mixture ◽  
R 134A ◽  
Air Conditioning Systems

Electrical energy consumption in air conditioning systems reaches 60% to 70% of the total electric energy consumption in buildings. Therefore, saving electrical energy consumption in air conditioning systems would have a significant impact on the national electrical energy consumption. Currently, the air conditioning sectors were having a dilemma on finding the alternative substitutes for CFC and HCFC refrigerants which are proven to cause destruction of the ozone layer and contribute to the effects of global warming. This paper will discuss the problems faced by an Article 5 country similar to Indonesia in phasing-out HCFC especially in air conditioning and refrigeration sectors. This paper will also discuss the possibility to use hydrocarbon-based refrigerants, which have zero ozone depletion potential (ODP) and low global warming potential (GWP), in air conditioning sectors. Some results of field applications of this refrigerant will be reported, and in general it can be concluded that the air conditioning retrofitted with hydrocarbon refrigerant consumes 10%–20% less electrical energy. Mixture of R-290 and R-134a was also investigated. R-134a is used to reduce the flammability of R-290 and to make the saturation pressure close to R-22. The results show that at composition of 0.6 R-290/0.4 R-134a mole fractions, the mixture behave as an azeotrope refrigerant mixture and can be used for R-22 replacement. At this composition, lower flammability limit (LEL) is 3693%, which is higher than pure R-290. Hence, the refrigerant mixture can be classified as less flammable A2 class refrigerant. The performance test shows that the refrigerant mixture can be used as a drop-in refrigerant in the R-22 machine. The measurement of refrigeration capacity and compressor input work at the same chilled water temperature shows that the calculated COP of the refrigerant mixture is better than R-22's but lower than R-290's.

scholarly journals Comparative Analysis of Energy Consumption, Indoor Thermal–Hygrometric Conditions, and Air Quality for HVAC, LDAC, and RDAC Systems Used in Operating Rooms

2020 ◽  
Vol 10 (11) ◽  
pp. 3721
Author(s):  
Tsung-Yi Chien ◽  
Ching-Chieh Liang ◽  
Feng-Jen Wu ◽  
Chi-Tsung Chen ◽  
Ting-Hsin Pan ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Air Quality ◽  
Air Conditioning ◽  
Operating Rooms ◽  
Conventional Heating ◽  
Hvac System ◽  
Total Energy Consumption ◽  
System A ◽  
Air Conditioning Systems ◽  
Daily Total

As controlling temperature and humidity is crucial for maintaining comfort and preventing microbial growth, operating rooms (ORs) are the most energy-intensive areas in hospitals. We aimed to evaluate the energy consumption of three dehumidification air conditioning systems used in ORs and their corresponding air quality for ORs at rest. This study selected three ORs using a conventional heating, ventilation, and air conditioning (HVAC) system; a liquid desiccant air conditioning (LDAC) system; and a rotary desiccant air conditioning (RDAC) system, respectively. The indoor thermal–hygrometric conditions, air quality, and energy consumption of the ORs were monitored in this study. The median levels of relative humidity (RH) were 66.7% in the OR using the conventional HVAC system, 60.8% in the OR using the LDAC system, and 60.5% in the OR using the RDAC system. The median daily total energy consumption of the RDAC system (10.1 kWh/m2) and LDAC system (11.8 kWh/m2) were 28.12% and 16.54% lower, respectively, than that of the conventional HVAC system (14.1 kWh/m2). The PM≥0.5 levels and airborne bacterial concentrations in the ORs met the ISO 14644-1 Class 7 standard and China’s GB50333-2013 standard, respectively. The RDAC system was clearly superior to the LDAC and conventional HVAC systems in terms of energy consumption.

scholarly journals Impact of Air Conditioning Systems on the Outdoor Thermal Environment during Summer in Berlin, Germany

2020 ◽  
Vol 17 (13) ◽  
pp. 4645 ◽  
Author(s):  
Luxi Jin ◽  
Sebastian Schubert ◽  
Mohamed Hefny Salim ◽  
Christoph Schneider
Keyword(s):  
Energy Consumption ◽  
Air Temperature ◽  
Air Conditioning ◽  
Waste Heat ◽  
Surface Air Temperature ◽  
Anthropogenic Heat ◽  
Reference Scenario ◽  
Indoor Temperature ◽  
Near Surface ◽  
Air Conditioning Systems

This study investigates the effect of anthropogenic heat emissions from air conditioning systems (AC) on air temperature and AC energy consumption in Berlin, Germany. We conduct simulations applying the model system CCLM/DCEP-BEM, a coupled system of the mesoscale climate model COSMO-CLM (CCLM) and the urban Double Canyon Effect Parameterization scheme with a building energy model (DCEP-BEM), for a summer period of 2018. The DCEP-BEM model is designed to explicitly compute the anthropogenic heat emissions from urban buildings and the heat flux transfer between buildings and the atmosphere. We investigate two locations where the AC outdoor units are installed: either on the wall of a building (VerAC) or on the rooftop of a building (HorAC). AC waste heat emissions considerably increase the near-surface air temperature. Compared to a reference scenario without AC systems, the VerAC scenario with a target indoor temperature of 22 ∘ C results in a temperature increase of up to 0.6 K . The increase is more pronounced during the night and for urban areas. The effect of HorAC on air temperature is overall smaller than in VerAC. With the target indoor temperature of 22 ∘ C , an urban site’s daily average AC energy consumption per floor area of a room is 9.1 W   m 2 , which is 35% more than that of a suburban site. This energy-saving results from the urban heat island effect and different building parameters between both sits. The maximum AC energy consumption occurs in the afternoon. When the target indoor temperature rises, the AC energy consumption decreases at a rate of about 16% per 2 K change in indoor temperature. The nighttime near-surface temperature in VerAC scenarios shows a declining trend ( 0.06 K per 2 K change) with increasing target indoor temperature. This feature is not obvious in HorAC scenarios which further confirms that HorAC has a smaller impact on near-surface air temperature.

scholarly journals Air Quality and Comfort Characterisation within an Electric Vehicle Cabin in Heating and Cooling Operations

Sensors ◽  
2022 ◽  
Vol 22 (2) ◽  
pp. 543
Author(s):  
Luigi Russi ◽  
Paolo Guidorzi ◽  
Beatrice Pulvirenti ◽  
Davide Aguiari ◽  
Giovanni Pau ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Air Quality ◽  
Electric Vehicle ◽  
Low Cost ◽  
Hvac System ◽  
Vehicle Cabin ◽  
Heating And Cooling ◽  
Cost System ◽  
Pollutant Concentrations ◽  
Comfort Parameters

This work is aimed at the experimental characterisation of air quality and thermal profile within an electric vehicle cabin, measuring at the same time the HVAC system energy consumption. Pollutant concentrations in the vehicle cabin are measured by means of a low-cost system of sensors. The effects of the HVAC system configuration, such as fresh-air and recirculation mode, on cabin air quality, are discussed. It is shown that the PM concentrations observed in recirculation mode are lower than those in fresh-air mode, while VOC concentrations are generally higher in recirculation than in fresh-air mode. The energy consumption is compared in different configurations of the HVAC system. The novelty of this work is the combined measurement of important comfort parameters such as air temperature distribution and air quality within the vehicle, together with the real time energy consumption of the HVAC system. A wider concept of comfort is enabled, based on the use of low-cost sensors in the automotive field.

scholarly journals Fast prediction for multi-parameters (concentration, temperature and humidity) of indoor environment towards the online control of HVAC system

2020 ◽  
Author(s):  
Hao-Cheng Zhu ◽  
Chen Ren ◽  
Shi-Jie Cao
Keyword(s):  
Energy Consumption ◽  
Air Temperature ◽  
Control Strategies ◽  
Ventilation Rate ◽  
Hvac Systems ◽  
Hvac System ◽  
Contribution Ratio ◽  
Temperature And Humidity ◽  
Fast Prediction ◽  
Low Dimensional

Abstract Heating, ventilation and air conditioning (HVAC) systems are the most energy-consuming building implements for the improvement of indoor environmental quality (IEQ). We have developed the optimal control strategies for HVAC system to respectively achieve the optimal selections of ventilation rate and supplied air temperature with consideration of energy conservation, through the fast prediction methods by using low-dimensional linear ventilation model (LLVM) based artificial neural network (ANN) and low-dimensional linear temperature model (LLTM) based contribution ratio of indoor climate (CRI(T)). To be continued for integrated control of multi-parameters, we further developed the fast prediction model for indoor humidity by using low-dimensional linear humidity model (LLHM) and contribution ratio of indoor humidity (CRI(H)), and thermal sensation index (TS) for assessment. CFD was used to construct the prediction database for CO2, temperature and humidity. Low-dimensional linear models (LLM), including LLVM, LLTM and LLHM, were adopted to expand database for the sake of data storage reduction. Then, coupling with ANN, CRI(T) and CRI(H), the distributions of indoor CO2 concentration, temperature, and humidity were rapidly predicted on the basis of LLVM-based ANN, LLTM-based CRI(T) and LLHM-based CRI(H), respectively. Finally, according to the self-defined indices (i.e., EV, ET, EH), the optimal balancing between IEQ (indicated by CO2 concentration, PMV and TS) and energy consumption (indicated by ventilation rate, supplied air temperature and humidity) were synthetically evaluated. The total HVAC energy consumption could be reduced by 35% on the strength of current control strategies. This work can further contribute to development of the intelligent online control for HVAC systems.

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