scholarly journals MODERN APPROACHES TO FORMATION HYDRAULIC MODES OF COOLING SUPPLY SYSTEMS

2021 ◽  
Vol 30 (1) ◽  
pp. 126-131
Author(s):  
V. Dzhedzhula ◽  
Keyword(s):  
Air Conditioning ◽  
Optimal Operation ◽  
Public Facility ◽  
Water Cooling ◽  
Refrigeration System ◽  
Cooling Systems ◽  
Hydraulic Regime ◽  
Significant Difference ◽  
Save Energy ◽  
Air Conditioning Systems

In modern conditions, the practice of building multi-storey office buildings, shopping centers and catering establishments where the installation of air conditioning systems is necessary is becoming widespread. In addition to regulatory requirements, the need for air conditioning systems is dictated by market conditions: a building in which optimal microclimatic conditions are created has significant competitive advantages in terms of renting, selling and operating compared to a building without ventilation and air conditioning systems. The main approaches to the installation of air conditioning systems are as follows: central air conditioning combined with ventilation and air heating; the use of local closers where the coolant is water - climate beams, fan coils; use of freon local systems - local and multizonal. Given the frequent inconsistency of planning and operational decisions of these buildings, due to the fact that different tenants may have different needs for the installation of air conditioning systems, different heat surpluses and other hazards, the installation of water cooling systems is one of the best solutions. within the limits of modernization of the system in accordance with the new operational features. Water cooling systems require the creation of an optimal hydraulic regime, which will not only allow optimal operation of refrigeration equipment, but also save energy. A significant difference in the formation of the hydraulic environment with constant and variable mode has formed the objectives of the study and confirms their relevance. The article considers the approaches to the formation of hydraulic modes of the refrigeration system. The results of the research were implemented during the construction of a real public facility. On the example of this object, the economic indicators of the formation of different hydraulic modes of the refrigeration system are determined. The use of the correct schemes for the formation of hydraulic modes of water cooling systems will significantly increase the energy efficiency of the process of forming the internal microclimate of these premises.

Thermal Energy Requirements of Air-Conditioning Systems

1971 ◽  
Vol 93 (2) ◽  
pp. 172-176
Author(s):  
M. E. Lackey
Keyword(s):  
Thermal Energy ◽  
Air Conditioning ◽  
Waste Heat ◽  
Energy Requirements ◽  
Absorption Refrigeration ◽  
Refrigeration System ◽  
Fast Breeder Reactors ◽  
Breeder Reactors ◽  
Absorption Refrigeration System ◽  
Air Conditioning Systems

The thermal energy requirements for air conditioning by compressive and absorption methods were determined for light-water, thermal-breeder, and fast-breeder reactors. The energy required to produce a ton-hour of refrigeration varied from 5100 Btu to 13,100 Btu by absorption and from 5600 to 8800 Btu by compression. The amount of waste heat dissipated to the environment at the reactor site as a consequence of producing a ton-hour of air conditioning ranged from an increase of 21,000 Btu for the electric-motor-driven refrigeration system to a decrease of 6000 Btu for the absorption refrigeration system.

The study of solar absorption air-conditioning systems

2005 ◽  
Vol 16 (4) ◽  
pp. 59-66 ◽  
Author(s):  
V Mittal ◽  
KS Kasana ◽  
NS Thakur
Keyword(s):  
Air Conditioning ◽  
Lithium Bromide ◽  
Cooling Systems ◽  
Solar Absorption ◽  
Air Conditioning System ◽  
Heating And Cooling ◽  
Absorption Cooling ◽  
Solar Powered ◽  
Solar Absorption Cooling ◽  
Air Conditioning Systems

An air-conditioning system utilizing solar energy would generally be more efficient, cost wise, if it was used to provide both heating and cooling requirements in the building it serves. Various solar powered heating systems have been tested extensively, but solar powered air conditioning systems have received very little attention. Solar powered absorption cooling systems can serve both heating and cooling requirements in the building it serves. Many researchers have studied the solar absorption air conditioning system in order to make it economically and technically viable. But still, much more research in this area is needed. This paper will help many researchers working in this area and provide them with fundamental knowledge on absorption systems, and a detailed review on the past efforts in the field of solar absorption cooling systems with the absorption pair of lithium-bromide and water. This knowledge will help them to start the parametric study in order to investigate the influence of key parameters on the overall system performance.

Condensation Induced Shock in Thermal/Fluid Systems

2012 ◽  
Author(s):  
Amir Jokar ◽  
Erik W. Christiansen
Keyword(s):  
Shock Waves ◽  
Phase Change ◽  
Air Conditioning ◽  
Industrial Applications ◽  
Governing Equations ◽  
Cooling Systems ◽  
Heating And Cooling ◽  
Fluid Systems ◽  
Air Conditioning Systems ◽  
Effective Life

Phase-change through condensation and evaporation processes takes place in many daily-use heating and cooling systems. However, if these processes experience uncontrolled pressure and temperature conditions, shock waves may be generated. Depending on the strength and conditions of the generated waves, they can decrease the effective life of equipment or even cause devastating destruction. Cavitation and water hammer phenomena are examples of flow issues that are well understood and reported in thermal/fluid systems, although not many studies have been published in open literature on condensation-induced shock (CIS) with the applications in refrigeration and air conditioning systems. This study reviews the limited literature on this topic, analyze the complex CIS phenomenon, derives and solves the governing equations, presents the results of typical conditions that may happen in different residential and industrial applications, and provides ways to avoid devastating incidents that may occur as a result of this phenomena.

Comparison of the Straight Adiabatic Capillary Tube Expansion Devices Used in Refrigeration Systems Operating With Refrigerants R134a and R1234yf

2016 ◽  
Vol 8 (2) ◽  
Author(s):  
S. S. Harish Kruthiventi ◽  
G. Venkatarathnam
Keyword(s):  
Speed Of Sound ◽  
Air Conditioning ◽  
Phase State ◽  
Capillary Tube ◽  
Phase Speed ◽  
Refrigeration System ◽  
Two Phase ◽  
Minimum Diameter ◽  
Air Conditioning Systems ◽  
Tube Expansion

Capillary tube expansion devices are used extensively in small refrigeration and unitary air conditioning systems. R1234yf is likely to replace R134a in the next few years in many small refrigeration systems worldwide because of the new environmental regulations being proposed. In this paper, we compare the length and diameter of capillary tube required when R134a and R1234yf are used in a typical small refrigeration system. The minimum diameter of the capillary tube required has been estimated using the speed of sound of the refrigerant leaving the capillary tube in the two-phase state. The two-phase speed of sound routine developed by us can be used with both pure fluids and mixtures.

scholarly journals Design of an adiabatic air conditioning package system

2022 ◽  
Vol 13 ◽  
pp. 8
Author(s):  
Sachin Sunil Mothiravally ◽  
Sachidananda Hassan Krishanmurthy
Keyword(s):  
Thermal Analysis ◽  
Energy Consumption ◽  
Return On Investment ◽  
Air Conditioning ◽  
Energy Savings ◽  
Coefficient Of Performance ◽  
Cooling Systems ◽  
Air Conditioning System ◽  
Adiabatic Cooling ◽  
Save Energy

Air conditioning plays a significant role to maintain a cool atmosphere in warm conditions, However, the power consumed by the machine is higher. The commercial prevailing cooling systems are required to operate ventilation and cooling systems in buildings and in turn consumes more power. These systems apart from consuming electricity it also adds to the CO2 emissions to our environment. These energy consumption and CO2 emissions can be decreased by the assistance of energy effective frameworks to the prevailing air conditioning system. The study was conducted on a package unit of 414.2 kW by measuring the relative humidity, dry bulb, and wet bulb temperature to investigate the effect of indirect evaporative cooling on the systems COP. Also, the modelling of the package unit was done using Creo software and the analysis was carried out using ANSYS considering the flow and thermal analysis for different components of the package units. From this analysis it can be observed that by implementing the adiabatic cooling in package unit it is possible to save energy consumption. From the results it can be concluded that energy efficiency was more and the return on investment is high. Also, coefficient of performance of this machine is high and consumes less electricity and the expected energy savings is 20%.

scholarly journals Progressive Development and Challenges Faced by Solar Rotary Desiccant-Based Air-Conditioning Systems: A Review

Processes ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 1785
Author(s):  
Ranjan Pratap Singh ◽  
Ranadip K. Das
Keyword(s):  
Solar Energy ◽  
Air Conditioning ◽  
Energy Use ◽  
Operating Cost ◽  
Electrical Energy ◽  
Low Grade ◽  
Vapor Compression ◽  
Cooling Systems ◽  
Ongoing Research ◽  
Air Conditioning Systems

A rotary desiccant-based air-conditioning system is a heat-driven hybrid system which combines different technologies such as desiccant dehumidification, evaporative cooling, refrigeration, and regeneration. This system has an opportunity to utilize low-grade thermal energy obtained from the sun or other sources. In this paper, the basic principles and recent research developments related to rotary desiccant-based cooling systems are recalled and their applications and importance are summarized. It is shown that with novel system configurations and new desiccant materials, there is great potential for improving the performance and consistency of rotary desiccant systems; at the same time, the use of solar energy for regeneration purposes can minimize the operating cost to a great extent. Some examples are presented to demonstrate how rotary desiccant air conditioning can be a promising solution for replacing traditional vapor-compression air-conditioning systems. Recent advances and ongoing research related to solar-powered hybrid rotary desiccant cooling systems are also summarized. The hybrid systems make use of a vapor-compression system in order to have better operational flexibility. These systems, although they consume electrical energy, use solar energy as the principal source of energy, and hence, significant savings of premium energy can be obtained compared to conventional vapor-compression systems. However, further research and development are required in order to realize the sustainable operation of solar rotary desiccant air-conditioning systems, as solar energy is not steady. Reductions in capital cost and size, along with improvements in efficiency and reliability of the system is still needed for it to become a player in the market of air conditioning.

Performance Enhancement of Solar Air Conditioners Using Hybrid Heat Rejection System

2019 ◽  
Author(s):  
Abdul Ahad Iqbal ◽  
Ali Al-Alili
Keyword(s):  
Air Conditioning ◽  
Cooling System ◽  
Vapor Compression ◽  
Summer Period ◽  
Cooling Systems ◽  
Hybrid Cooling ◽  
Vapor Compression Cooling ◽  
Air Conditioning Systems ◽  
Sorption Systems ◽  
Dry Cooling

Abstract The performance of air conditioning systems is highly dependent on the environmental conditions of the high pressure side, where heat is rejected to the environment. Air conditioning systems utilize dry cooling systems which often don’t provide adequate cooling during peak cooling periods, or wet cooling systems which consume a lot of water. In this study, a novel hybrid cooling system that can provide both wet and dry cooling was modelled in TRNSYS, and used to provide cooling to closed sorption air conditioning systems. The performance of these systems with the hybrid cooling system was compared to the performance of a standard vapor compression cooling system being cooled by a dry cooling system. The COPsol of the vapor compression cooling system exhibited a decrease of almost 26% during the summer period, whereas the COPsol of the sorption systems increased by around 30%. Similarly, the cooling capacity of the vapor compression cooling system dropped by almost 5%, and for the sorption systems, it increased by around 20% during the summer period.

scholarly journals Solar hybrid air conditioning system to use in Iraq to save energy

2019 ◽  
Vol 124 ◽  
pp. 01024
Author(s):  
Y. V. Vankov ◽  
A. K. Al–Okbi ◽  
M. H. Hasanen
Keyword(s):  
Air Conditioning ◽  
Power Plants ◽  
Cooling System ◽  
Renewable Energy Sources ◽  
Electricity Consumption ◽  
Air Conditioners ◽  
Reduce Electricity Consumption ◽  
Central Air Conditioning ◽  
Save Energy ◽  
Air Conditioning Systems

The energy saving issues are becoming necessary worldwide, as excessive consumption of energy leads to the consumption of a larger amount of fuel, increases environmental pollution and negatively affects the ozone layer. In Iraq, in particular, the demand for central air conditioning systems and home air conditioners with high electrical capacity has become increasingly clear in the recent years. Air conditioning systems within residential and public buildings, as well as government facilities became a necessity for good internal comfort, which was driven by desertification, high temperature, air pollution and increased population, resulting in increased consumption of electric power and pressing of power plants. Aiming at usage of renewable energy sources, the proposed system uses solar collectors as auxiliary solar thermal compressors and integrate them with air conditioning systems. The proposed solution will increase the cooling system efficiency, reduce electricity consumption and pollution.

scholarly journals The Significance of the Adaptive Thermal Comfort Limits on the Air-Conditioning Loads in a Temperate Climate

2019 ◽  
Vol 11 (2) ◽  
pp. 328 ◽  
Author(s):  
Aiman Albatayneh ◽  
Dariusz Alterman ◽  
Adrian Page ◽  
Behdad Moghtaderi
Keyword(s):  
Thermal Comfort ◽  
Air Conditioning ◽  
Temperate Climate ◽  
Heating And Cooling ◽  
Air Temperatures ◽  
Adaptive Thermal Comfort ◽  
Save Energy ◽  
One Year ◽  
Air Conditioning Systems ◽  
Thermal Comfort Model

The building industry is regarded a major contributor to climate change as energy consumption from buildings accounts for 40% of the total energy. The types of thermal comfort models used to predict the heating and cooling loads are critical to save energy in operative buildings and reduce greenhouse gas emissions (GHG). In this research, the internal air temperatures were recorded for over one year under the free floating mode with no heating or cooling, then the number of hours required for heating or cooling were calculated based on fixed sets of operative temperatures (18 °C–24 °C) and the adaptive thermal comfort model to estimate the number of hours per year required for cooling and heating to sustain the occupants’ thermal comfort for four full-scale housing test modules at the campus of the University of Newcastle, Australia. The adaptive thermal comfort model significantly reduced the time necessary for mechanical cooling and heating by more than half when compared with the constant thermostat setting used by the air-conditioning systems installed on the site. It was found that the air-conditioning system with operational temperature setups using the adaptive thermal comfort model at 80% acceptability limits required almost half the operating energy when compared with fixed sets of operating temperatures. This can be achieved by applying a broader range of acceptable temperature limits and using techniques that require minimal energy to sustain the occupants’ thermal comfort.

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