scholarly journals ANALYSIS OF THE ENERGY, ECONOMIC AND ENVIRONMENTAL EFFICIENCY OF AIR CONDITIONING SYSTEMS WITH DIRECT AND INDIRECT EVAPORATIVE COOLING

2021 ◽  
Vol 2 (46) ◽  
pp. 16
Author(s):  
E. Dmytrochenkova
Keyword(s):  
Carbon Dioxide Emissions ◽  
Air Conditioning ◽  
Evaporative Cooling ◽  
Environmental Efficiency ◽  
Ecological Effect ◽  
Air Conditioner ◽  
Cooling Mode ◽  
Adiabatic Cooling ◽  
Indirect Evaporative Cooling ◽  
Air Conditioning Systems

The article is devoted to the analysis of energy, economic and environmental efficiency, which are achieved by using indirect adiabatic cooling of air in the central air conditioner instead of direct cooling. Two corresponding schematic diagrams of air conditioning systems are considered. As a result of the calculations, it was found that indirect adiabatic cooling of the air makes it possible to reduce the consumption of cold and electricity by 65%. The monetary equivalent of reducing energy consumption can reach UAH 14,760 for 4 months of operation of the air conditioning system in cooling mode. Also, the use of this mode of operation of climatic equipment makes it possible to obtain a certain environmental effect in the form of reducing carbon dioxide emissions at the level of 5.15 tons per season.Keywords: indirect evaporative cooling, refrigeration capacity, irrigation chamber, economic efficiency, ecological effect

scholarly journals Experimental Investigation of a Split Air Conditioning Using Condensate as Direct Evaporative Cooling

2021 ◽  
Vol 86 (1) ◽  
pp. 140-153
Author(s):  
Azridjal Aziz ◽  
Muhammad Rif’at Syahnan ◽  
Afdhal Kurniawan Mainil ◽  
Rahmat Iman Mainil
Keyword(s):  
Air Conditioning ◽  
Evaporative Cooling ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Cooling Load ◽  
Air Conditioner ◽  
Direct Evaporative Cooling ◽  
Compressor Power ◽  
Discharge Pressure ◽  
Air Conditioning Systems

Split air conditioning systems produce reasonable amount of condensate which is usually not utilized and thrown away to the environment. On the other hand, it consumes a lot of energy during operation. The aim of this study is to investigate the improvement of air conditioning systems performance utilizing condensate. A direct evaporative cooling using condensate is incorporated on a 0.74 ton-cooling capacity of split air conditioning to decrease the air temperature before entering the condenser. Performances of the split air conditioning with and without direct evaporative cooling are compared and presented in this paper. The results show that the use of direct evaporative cooling using condensate into the air before passing through the condenser reduces the compressor discharge pressure. The decrease of the condenser pressure led to 4.7% and 7% reduction of power consumption for air conditioner without cooling load and air conditioner with 2000 W cooling load, respectively. The cooling effect and coefficient of performance (COP) increase with the decrease of compressor power. The use of direct evaporative cooling with condensate into the air before entering the condensing system can enhance the system performance and protect the environment.

scholarly journals Central Air Conditioning Systems with Partial Indirect Evaporative Cooling and Utilization of Cold and Heat of Ventilation Emissions

2021 ◽  
pp. 35-41
Author(s):  
Mykhaylo Bozhenko ◽  
Tatiana Izhevska
Keyword(s):  
Energy Efficiency ◽  
Air Conditioning ◽  
Evaporative Cooling ◽  
Cold Season ◽  
Warm Period ◽  
Direct Flow ◽  
Recirculation Rate ◽  
Indirect Evaporative Cooling ◽  
Air Conditioning Systems ◽  
Flow Circuit

A promising trend in air conditioning systems is the use of indirect evaporative cooling, but in the classic version it is effective in dry and hot climates. For the need to maintain comfortable air parameters in public buildings, it is not possible to fully implement such a process in the conditions of Ukraine (the relative humidity of the outside air ranges from 63 to 75 %). The aim of the work is to increase the energy efficiency of air conditioning systems with standard equipment through partial evaporative cooling and use for cooling water in cooling towers of the air removed from the rooms during the warm season, and in the cold season - use of the exhaust air for preheating the supply air in heat exchanger. A corresponding system diagram was developed and computational studies of a direct-flow circuit and a circuit with recirculation were carried out for one of the educational buildings of the Igor Sikorsky Kyiv Polytechnic Institute. According to the results of calculating the direct-flow circuit in the warm period, the energy efficiency of indirect evaporative cooling was 23.5 %. The annual amount of recovered heat of ventilation emissions for this scheme in the cold period was 3731 GJ / year, and the economic effect - 1473185 UAH / year. For a circuit with recirculation during a warm period, the greatest effect of indirect evaporative cooling is achieved with a recirculation rate of 10 %, and for the overall decrease in the cooling capacity of the air conditioner during this period the greatest impact is not indirect evaporative cooling, but recirculation. In the cold season, the greatest utilization effect is also achieved with a 10 % recirculation rate.

scholarly journals Indoor Air Quality Enhancement Performance of Liquid Desiccant and Evaporative Cooling-Assisted Air Conditioning Systems

2019 ◽  
Vol 11 (4) ◽  
pp. 1036 ◽  
Author(s):  
Beom-Jun Kim ◽  
Junseok Park ◽  
Jae-Weon Jeong
Keyword(s):  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Reference System ◽  
Air Conditioning ◽  
Evaporative Cooling ◽  
Quality Enhancement ◽  
Liquid Desiccant ◽  
Air Conditioning Systems ◽  
Indoor Pm2.5

The main objective of this study is to investigate the indoor air quality enhancement performance of two different liquid desiccant and evaporative cooling-assisted air conditioning systems, such as the variable air volume (VAV) system with the desiccant-enhanced evaporative (DEVap) cooler, and the liquid desiccant system with an indirect and direct evaporative cooling-assisted 100% outdoor air system (LD-IDECOAS), compared with the conventional VAV system. The transient simulations of concentration variations of carbon dioxide (CO2), coarse particles, and fine particles (PM10 and PM2.5) in a model office space served by each system were performed using validated system models that were found in the literature. Based on the hourly thermal loads of the model space predicted by the TRNSYS 18 program, each air conditioning system was operated virtually using a commercial equation solver program (EES). The results indicated that the LD-IDECOAS provided the lowest annual indoor CO2 concentration among all the systems considered in this research, while the VAV system with DEVap cooler exceeded the threshold concentration (i.e., 1000 ppm) during the cooling season (i.e., July, August, and September). For the indoor particulate contaminant concentrations, both liquid desiccant and evaporative cooling-assisted air conditioning systems indicated lower indoor PM2.5 and PM10 concentrations compared with the reference system. The LD-IDECOAS and the VAV with a DEVap cooler demonstrated 33.3% and 23.5% lower annual accumulated indoor PM10 concentrations than the reference system, respectively. Similarly, the annual accumulated indoor PM2.5 concentration was reduced by 16% using the LD-IDECOAS and 17.1% using the VAV with DEVap cooler.

Preserving Passenger Comfort Through RWI Analysis

2012 ◽  
Author(s):  
Mark P. Colino ◽  
Elena B. Rosenstein
Keyword(s):  
Emergency Preparedness ◽  
Air Conditioning ◽  
Operating Pressure ◽  
Cooling Mode ◽  
Tunnel Ventilation ◽  
Passenger Comfort ◽  
Passenger Rail ◽  
Warmth Index ◽  
Emergency Events ◽  
Air Conditioning Systems

The air conditioning systems designed for passenger rail cars typically exchange heat with the outside air environment; when the trains operate within tunnels, the effectiveness of the air conditioning systems may diminish if the tunnel is too warm. Therefore, one of the traditional activation modes associated with rail tunnel ventilation systems is summertime cooling — for the purpose of maintaining onboard passenger comfort. However, summertime cooling modes can be problematic from the standpoints of fan operating pressure (i.e. an opposing air pressure is created whenever trains approach ventilation shafts), energy consumption and emergency preparedness (i.e. fans operating in the wrong direction when a fire is detected). In this paper, the thermal comfort of rail transportation passengers was studied in detail using the Relative Warmth Index (RWI) analyses to determine if the combination of: warm outdoor weather, the tunnel heat-sink effect, the rail coach design air temperature and typical commuting scenarios necessitated running the tunnel fans in a summertime cooling mode to preserve passenger comfort. If the summertime cooling mode could be eliminated, or even minimized, the tunnel ventilation usage/operating costs would be reduced, the fans would have a longer service life and the system would have greater overall availability for emergency events.

scholarly journals Energy Performance Comparison between Two Liquid Desiccant and Evaporative Cooling-Assisted Air Conditioning Systems

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 522
Author(s):  
Su Liu ◽  
Jae-Weon Jeong
Keyword(s):  
Energy Consumption ◽  
Air Conditioning ◽  
Evaporative Cooling ◽  
Dew Point ◽  
Outdoor Air ◽  
Liquid Desiccant ◽  
Energy Saving Potential ◽  
Evaporative Cooler ◽  
Air Conditioning Systems ◽  
Direct Evaporative Cooler

This study investigated the annual energy saving potential and system performance of two different evaporative cooling-based liquid desiccant and evaporative cooling-assisted air conditioning systems. One system used an indirect and direct evaporative cooler with a two-stage package to match the target supply air point. The other was equipped with a single-stage, packaged dew-point evaporative cooler that used a portion of the process air, which had been dehumidified in advance. Systems installed with the two evaporative coolers were compared to determine which one was more energy efficient and which one could provide better thermal comfort for building occupants in a given climate zone, using detailed simulation data. The detailed energy consumption data of these two systems were estimated using an engineering equation solver with each component model. The results showed that the liquid desiccant and dew-point evaporative-cooler-assisted 100% outdoor air system (LDEOAS) resulted in approximately 34% more annual primary energy consumption than that of the liquid desiccant and the indirect and direct evaporative-cooler-assisted 100% outdoor air system (LDIDECOAS). However, the LDEOAS could provide drier and cooler supply air, compared with the LDIDECOAS. In conclusion, LDIDECOAS has a higher energy saving potential than LDEOAS, with an acceptable level of thermal comfort.

Experimental Investigation on a Grid-Connected Photovoltaic Air Conditioning System

2014 ◽  
Vol 672-674 ◽  
pp. 54-60 ◽  
Author(s):  
Ting Xiang Jin ◽  
Xiao Feng Xu
Keyword(s):  
Solar Energy ◽  
Energy Demand ◽  
Air Conditioning ◽  
Experimental Result ◽  
Stable Operation ◽  
Air Conditioner ◽  
Renewable Energy Consumption ◽  
Air Conditioning System ◽  
New Energy ◽  
Air Conditioning Systems

As coal, oil, natural gas and other non-renewable energy consumption and increasing energy demand, the utilization of solar energy as a new energy is greatly enhanced. In this work, a grid connected photovoltaic solar air conditioning system is designed, mainly comprised of solar panel, controller, inverter, room air conditioner and other parts. Air conditioning systems rely mainly on solar photovoltaic power; achieve the effect of energy conservation and environmental protection. The experimental result indicates that the system can achieve stable operation and the utilization of solar energy driving air conditioning system to save electricity. This air conditioning system is compared with the ordinary air conditioning system, SEER can increase 10.6 ~ 29.4%, HSPF can increase 6.25 ~ 18.5%.

scholarly journals Feasibility study for the use of variable air volume systems for office buildings

2021 ◽  
Vol 36 ◽  
pp. 62-79
Author(s):  
A. Moskvitina ◽  
M.  Shyshyna ◽  
M. Korchminskyi
Keyword(s):  
Greenhouse Gas Emissions ◽  
Greenhouse Gas ◽  
Carbon Dioxide Emissions ◽  
Air Conditioning ◽  
Office Buildings ◽  
Operating Costs ◽  
Gas Emissions ◽  
Variable Air Volume ◽  
Air Volume ◽  
Air Conditioning Systems

The main factor contributing to greenhouse gas emissions is the building up of the surrounding area. Studies have shown that buildings globally consume 30-40 % of energy use and release 40-50 % of global carbon dioxide emissions. Among all systems in houses, heating, ventilation and air conditioning (HVAC) systems are by far the most energy intensive. They consume approximately 50 % of the total energy demand of buildings. However, the systems are some of the most important systems in today's buildings. The number of these systems that are being installed has increased dramatically over the past few years. This is mainly due to the increasing demands for thermal energy, comfort and climate change. This paper presents a feasibility and ecology study between two ventilation or air-conditioning systems: constant air volume (CAV) and variable air volume (VAV). One of the purposes of this work is to determine the energy costs for each of the systems. An air conditioning system that saves operating costs usually requires a large initial investment. In this case, engineers must decide whether it is worth paying the additional upfront costs for a system that has lower operating costs. Despite the low attractiveness from the point of view of the investor, the VAV systems reduce the amount of greenhouse gas emissions and the amount of energy resources for servicing the commercial sector. Such system have less metal consumption. Thus, the cost of metal processing is also reduced. The results of this study can contribute to the future selection of ventilation systems, as well as contribute to the design and improvement of the systems under study. Energy saving is one of the main reasons why VAV systems are very popular today for the design of ventilation and air conditioning systems for office buildings and in many industries abroad. With these systems, the volume of transported air is reduced as soon as the operating load falls below the maximum projected load. The calculation of emissions of harmful substances into the environment was made while ensuring the operation of CAV and VAV systems.

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